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+The Project Gutenberg eBook, Aviation Engines, by Victor Wilfred Pagé
+
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever. You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+
+
+
+Title: Aviation Engines
+ Design--Construction--Operation and Repair
+
+
+Author: Victor Wilfred Pagé
+
+
+
+Release Date: December 2, 2011 [eBook #38187]
+
+Language: English
+
+Character set encoding: ISO-646-US (US-ASCII)
+
+
+***START OF THE PROJECT GUTENBERG EBOOK AVIATION ENGINES***
+
+
+E-text prepared by Juliet Sutherland, Harry Lamé, and the Online
+Distributed Proofreading Team (http://www.pgdp.net)
+
+
+
+Note: Project Gutenberg also has an HTML version of this
+ file which includes the original illustrations.
+ See 38187-h.htm or 38187-h.zip:
+ (http://www.gutenberg.org/files/38187/38187-h/38187-h.htm)
+ or
+ (http://www.gutenberg.org/files/38187/38187-h.zip)
+
+
+ +-----------------------------------------------------------------+
+ | TRANSCRIBER'S NOTES |
+ | |
+ | Transcription used for this e-text: |
+ | Italic text in the original work is transcribed between |
+ | underscores, as in _text_; |
+ | Bold face text in the original work is transcribed between |
+ | equal signs, as in =text=; |
+ | Bold face underlined text in the original work is transcribed |
+ | between tildes, as in ~text~; |
+ | Super- and subscripts in the original work are transcribed as |
+ | ^{text} and _{text}, respectively; |
+ | Greek characters have been transcribed as [alpha], [beta], |
+ | etc.; |
+ | The oe-ligature in Phoenix has been transcribed as oe. |
+ | |
+ | Some in-line multi-line formulas have been transcribed as |
+ | single-line formulas, where necessary with brackets added. |
+ | |
+ | Some table headings have been replaced by legends [A], [B], etc;|
+ | these are listed directly above the relevant tables. |
+ | |
+ | More extensive Transcriber's Notes may be found at the end of |
+ | this text. |
+ +-----------------------------------------------------------------+
+
+
+
+
+
+AVIATION ENGINES
+
+Design--Construction--Operation and Repair
+
+by
+
+FIRST LIEUT. VICTOR W. PAGE, A. S. S. C., U. S. R.
+
+
+ * * * * *
+
+
+~JUST PUBLISHED~
+
+
+=AVIATION ENGINES. Their Design, Construction, Operation and Repair.=
+
+ By Lieut. VICTOR W. PAGE, Aviation Section, S.C.U.S.R.
+
+ A practical work containing valuable instructions for aviation
+ students, mechanicians, squadron engineering officers and all
+ interested in the construction and upkeep of airplane power
+ plants. 576 octavo pages. 250 illustrations. Price $3.00.
+
+
+=AVIATION CHART, or the Location of Airplane Power Plant Troubles Made
+Easy.=
+
+ By Lieut. VICTOR W. PAGE, A.S., S.C.U.S.R.
+
+ A large chart outlining all parts of a typical airplane power
+ plant, showing the points where trouble is apt to occur and
+ suggesting remedies for the common defects. Intended especially
+ for aviators and aviation mechanics on school and field duty.
+ Price 50 cents.
+
+
+=GLOSSARY OF AVIATION TERMS.=
+
+ Compiled by Lieuts. VICTOR W. PAGE, A.S., S.C.U.S.R. and PAUL
+ MONTARIOL of the French Flying Corps on duty at Signal Corps
+ Aviation School, Mineola, L. I.
+
+ A complete glossary of practically all terms used in aviation,
+ having lists in both French and English, with equivalents in
+ either language. A very valuable book for all who are about to
+ leave for duty overseas. Price, cloth, $1.00.
+
+
+=THE NORMAN W. HENLEY PUBLISHING COMPANY=
+
+2 WEST 45TH ST., NEW YORK
+
+ * * * * *
+
+
+[Illustration: Part Sectional View of Hall-Scott Airplane Motor, Showing
+Principal Parts.]
+
+
+ * * * * *
+
+CENSORED
+
+This Book Entitled
+
+AVIATION ENGINES
+
+By LIEUT. VICTOR W. PAGE
+
+has been censored by the United States Government, and pages and
+parts of pages have been omitted by special instructions from
+Washington.
+
+The book has been passed by THE COMMITTEE ON PUBLIC INFORMATION
+and is as complete as we can furnish it, and we so advise the
+purchaser of it.
+
+THE NORMAN W. HENLEY PUBLISHING COMPANY
+
+
+ * * * * *
+
+
+AVIATION ENGINES
+
+Design--Construction--Operation and Repair
+
+A Complete, Practical Treatise Outlining Clearly
+the Elements of Internal Combustion Engineering
+with Special Reference to the Design, Construction,
+Operation and Repair of Airplane Power
+Plants; Also the Auxiliary Engine Systems, Such
+as Lubrication, Carburetion, Ignition and Cooling.
+
+It Includes Complete Instructions for Engine
+Repairing and Systematic Location of Troubles,
+Tool Equipment and Use of Tools, Also Outlines
+the Latest Mechanical Processes.
+
+by
+
+FIRST LIEUT. VICTOR W. PAGE, A. S. S. C., U. S. R.
+
+Assistant Engineering Officer, Signal Corps Aviation School,
+Mineola, L. I.
+
+Author of "The Modern Gasoline Automobile," Etc.
+
+[Illustration]
+
+Contains Valuable Instructions for All Aviation Students,
+Mechanicians, Squadron Engineering Officers and All Interested in
+the Construction and Upkeep of Airplane Power Plants.
+
+
+
+
+
+
+
+New York
+The Norman W. Henley Publishing Company
+2 West 45th Street
+1917
+
+Copyrighted, 1917
+By
+The Norman W. Henley Publishing Co.
+
+Printed in U. S. A.
+
+All Illustrations in This Book Have Been
+Specially Made by the Publishers, and Their
+Use, Without Permission, Is Strictly Prohibited
+
+Composition, Electrotyping and Presswork
+by the Publishers Printing Co., New York
+
+
+
+
+PREFACE
+
+
+In presenting this treatise on "Aviation Engines," the writer realizes
+that the rapidly developing art makes it difficult to outline all latest
+forms or describe all current engineering practice. This exposition has
+been prepared primarily for instruction purposes and is adapted for men
+in the Aviation Section, Signal Corps, and students who wish to become
+aviators or aviation mechanicians. Every effort has been made to have
+the engineering information accurate, but owing to the diversity of
+authorities consulted and use of data translated from foreign language
+periodicals, it is expected that some slight errors will be present. The
+writer wishes to acknowledge his indebtedness to such firms as the
+Curtiss Aeroplane and Motor Co., Hall-Scott Company, Thomas-Morse
+Aircraft Corporation and General Vehicle Company for photographs and
+helpful descriptive matter. Special attention has been paid to
+instructions on tool equipment, use of tools, trouble "shooting" and
+engine repairs, as it is on these points that the average aviation
+student is weakest. Only such theoretical consideration of
+thermo-dynamics as was deemed absolutely necessary to secure a proper
+understanding of engine action after consulting several instructors is
+included, the writer's efforts having been confined to the preparation
+of a practical series of instructions that would be of the greatest
+value to those who need a diversified knowledge of internal-combustion
+engine operation and repair, and who must acquire it quickly. The
+engines described and illustrated are all practical forms that have been
+fitted to airplanes capable of making flights and may be considered
+fairly representative of the present state of the art.
+
+VICTOR W. PAGE,
+
+_1st Lieut. A. S. S. C., U. S. R_.
+
+MINEOLA, L. I.,
+
+October, 1917.
+
+
+
+
+CONTENTS
+
+
+ PAGES
+ CHAPTER I
+
+ Brief Consideration of Aircraft Types--Essential Requirements of
+ Aerial Motors--Aviation Engines Must Be Light--Factors Influencing
+ Power Needed--Why Explosive Motors Are Best--Historical--Main
+ Types of Internal Combustion Engines 17-36
+
+ CHAPTER II
+
+ Operating Principles of Two- and Four-Stroke Engines--Four-cycle
+ Action--Two-cycle Action--Comparing Two- and Four-cycle Types--
+ Theory of Gas and Gasoline Engine--Early Gas-Engine Forms--
+ Isothermal Law--Adiabatic Law--Temperature Computations--Heat and
+ Its Work--Conversion of Heat to Power--Requisites for Best Power
+ Effect 37-59
+
+ CHAPTER III
+
+ Efficiency of Internal Combustion Engines--Various Measures of
+ Efficiency--Temperatures and Pressures--Factors Governing Economy
+ --Losses in Wall Cooling--Value of Indicator Cards--Compression in
+ Explosive Motors--Factors Limiting Compression--Causes of Heat
+ Losses and Inefficiency--Heat Losses to Cooling Water 60-79
+
+ CHAPTER IV
+
+ Engine Parts and Functions--Why Multiple Cylinder Engines Are Best
+ --Describing Sequence of Operations--Simple Engines--Four and Six
+ Cylinder Vertical Tandem Engines--Eight and Twelve Cylinder V
+ Engines--Radial Cylinder Arrangement--Rotary Cylinder Forms 80-109
+
+ CHAPTER V
+
+ Properties of Liquid Fuels--Distillates of Crude Petroleum--
+ Principles of Carburetion Outlined--Air Needed to Burn Gasoline--
+ What a Carburetor Should Do--Liquid Fuel Storage and Supply--
+ Vacuum Fuel Feed--Early Vaporizer Forms--Development of Float Feed
+ Carburetor--Maybach's Early Design--Concentric Float and Jet Type
+ --Schebler Carburetor--Claudel Carburetor--Stewart Metering Pin
+ Type--Multiple Nozzle Vaporizers--Two-Stage Carburetor--Master
+ Multiple Jet Type--Compound Nozzle Zenith Carburetor--Utility of
+ Gasoline Strainers--Intake Manifold Design and Construction--
+ Compensating for Various Atmospheric Conditions--How High
+ Altitude Affects Power--The Diesel System--Notes on Carburetor
+ Installation--Notes on Carburetor Adjustment 110-154
+
+ CHAPTER VI
+
+ Early Ignition Systems--Electrical Ignition Best--Fundamentals of
+ Magnetism Outlined--Forms of Magneto--Zones of Magnetic Influence
+ --How Magnets are Made--Electricity and Magnetism Related--Basic
+ Principles of Magneto Action--Essential Parts of Magneto and
+ Functions--Transformer Coil Systems--True High Tension Type--The
+ Berling Magneto--Timing and Care--The Dixie Magneto--Spark-Plug
+ Design and Application--Two-Spark Ignition--Special Airplane
+ Plug 155-200
+
+ CHAPTER VII
+
+ Why Lubrication Is Necessary--Friction Defined--Theory of
+ Lubrication--Derivation of Lubricants--Properties of Cylinder Oils
+ --Factors Influencing Lubrication System Selection--Gnome Type
+ Engines Use Castor Oil--Hall-Scott Lubrication System--Oil Supply
+ by Constant Level Splash System--Dry Crank-Case System Best for
+ Airplane Engines--Why Cooling Systems Are Necessary--Cooling
+ Systems Generally Applied--Cooling by Positive Pump Circulation--
+ Thermo-Syphon System--Direct Air-Cooling Methods--Air-Cooled
+ Engine Design Considerations 201-232
+
+ CHAPTER VIII
+
+ Methods of Cylinder Construction--Block Castings--Influence on
+ Crank-Shaft Design--Combustion Chamber Design--Bore and Stroke
+ Ratio--Meaning of Piston Speed--Advantage of Off-Set Cylinders--
+ Valve Location of Vital Import--Valve Installation Practice--Valve
+ Design and Construction--Valve Operation--Methods of Driving
+ Cam-Shaft--Valve Springs--Valve Timing--Blowing Back--Lead Given
+ Exhaust Valve--Exhaust Closing, Inlet Opening--Closing the
+ Inlet Valve--Time of Ignition--How an Engine is Timed--Gnome
+ "Monosoupape" Valve Timing--Springless Valves--Four Valves per
+ Cylinder 233-286
+
+ CHAPTER IX
+
+ Constructional Details of Pistons--Aluminum Cylinders and Pistons
+ --Piston Ring Construction--Leak Proof Piston Rings--Keeping Oil
+ Out of Combustion Chamber--Connecting Rod Forms--Connecting Rods
+ for Vee Engines--Cam-Shaft and Crank-Shaft Designs--Ball Bearing
+ Crank-Shafts--Engine Base Construction 287-323
+
+ CHAPTER X
+
+ Power Plant Installation--Curtiss OX-2 Engine Mounting and
+ Operating Rules--Standard S. A. E. Engine Bed Dimensions--
+ Hall-Scott Engine Installation and Operation--Fuel System Rules
+ --Ignition System--Water System--Preparations to Start Engine--
+ Mounting Radial and Rotary Engines--Practical Hints to Locate
+ Engine Troubles--All Engine Troubles Summarized--Location of
+ Engine Troubles Made Easy 324-375
+
+ CHAPTER XI
+
+ Tools for Adjusting and Erecting--Forms of Wrenches--Use and Care
+ of Files--Split Pin Removal and Installation--Complete Chisel Set
+ --Drilling Machines--Drills, Reamers, Taps and Dies--Measuring
+ Tools--Micrometer Calipers and Their Use--Typical Tool Outfits
+ --Special Hall-Scott Tools--Overhauling Airplane Engines--Taking
+ Engine Down--Defects in Cylinders--Carbon Deposits, Cause and
+ Prevention--Use of Carbon Scrapers--Burning Out Carbon with
+ Oxygen --Repairing Scored Cylinders--Valve Removal and Inspection
+ --Reseating and Truing Valves--Valve Grinding Processes--
+ Depreciation in Valve Operating System--Piston Troubles--Piston
+ Ring Manipulation--Fitting Piston Rings--Wrist-Pin Wear--
+ Inspection and Refitting of Engine Bearings--Scraping Brasses to
+ Fit--Fitting Connecting Rods--Testing for Bearing Parallelism--
+ Cam-Shafts and Timing Gears--Precautions in Reassembling Parts 376-456
+
+ CHAPTER XII
+
+ Aviation Engine Types--Division in Classes--Anzani Engines--Canton
+ and Unne Engine--Construction of Gnome Engines--"Monosoupape"
+ Gnome--German "Gnome" Type--Le Rhone Engine--Renault Air-Cooled
+ Engine--Simplex Model "A" Hispano-Suiza--Curtiss Aviation Motors--
+ Thomas-Morse Model 88 Engine--Duesenberg Engine--Aeromarine
+ Six-Cylinder--Wisconsin Aviation Engines--Hall-Scott Engines--
+ Mercedes Motor--Benz Motor--Austro-Daimler Engine--Sunbeam-Coatalen
+ --Indicating and Measuring Instruments--Air Starting Systems--
+ Electric Starting--Battery Ignition 457-571
+
+ INDEX 573
+
+ LIST OF ILLUSTRATIONS
+
+
+
+
+AVIATION ENGINES
+
+DESIGN--CONSTRUCTION--REPAIR
+
+
+
+
+CHAPTER I
+
+ Brief Consideration of Aircraft Types--Essential Requirements of
+ Aerial Motors--Aviation Engines Must Be Light--Factors
+ Influencing Power Needed--Why Explosive Motors Are Best--
+ Historical--Main Types of Internal Combustion Engines.
+
+
+BRIEF CONSIDERATION OF AIRCRAFT TYPES
+
+The conquest of the air is one of the most stupendous achievements of
+the ages. Human flight opens the sky to man as a new road, and because
+it is a road free of all obstructions and leads everywhere, affording
+the shortest distance to any place, it offers to man the prospect of
+unlimited freedom. The aircraft promises to span continents like
+railroads, to bridge seas like ships, to go over mountains and forests
+like birds, and to quicken and simplify the problems of transportation.
+While the actual conquest of the air is an accomplishment just being
+realized in our days, the idea and yearning to conquer the air are old,
+possibly as old as intellect itself. The myths of different races tell
+of winged gods and flying men, and show that for ages to fly was the
+highest conception of the sublime. No other agent is more responsible
+for sustained flight than the internal combustion motor, and it was only
+when this form of prime mover had been fully developed that it was
+possible for man to leave the ground and alight at will, not depending
+upon the caprices of the winds or lifting power of gases as with the
+balloon. It is safe to say that the solution of the problem of flight
+would have been attained many years ago if the proper source of power
+had been available as all the essential elements of the modern
+aeroplane and dirigible balloon, other than the power plant, were known
+to early philosophers and scientists.
+
+Aeronautics is divided into two fundamentally different
+branches--aviatics and aerostatics. The first comprises all types of
+aeroplanes and heavier than air flying machines such as the helicopters,
+kites, etc.; the second includes dirigible balloons, passive balloons
+and all craft which rise in the air by utilizing the lifting force of
+gases. Aeroplanes are the only practical form of heavier-than-air
+machines, as the helicopters (machines intended to be lifted directly
+into the air by propellers, without the sustaining effect of planes),
+and ornithopters, or flapping wing types, have not been thoroughly
+developed, and in fact, there are so many serious mechanical problems to
+be solved before either of these types of air craft will function
+properly that experts express grave doubts regarding the practicability
+of either. Aeroplanes are divided into two main types--monoplanes or
+single surface forms, and bi-planes or machines having two sets of
+lifting surfaces, one suspended over the other. A third type, the
+triplane, is not very widely used.
+
+Dirigible balloons are divided into three classes: the rigid, the
+semi-rigid, and the non-rigid. The rigid has a frame or skeleton of
+either wood or metal inside of the bag, to stiffen it; the semi-rigid is
+reinforced by a wire net and metal attachments; while the non-rigid is
+just a bag filled with gas. The aeroplane, more than the dirigible and
+balloon, stands as the emblem of the conquest of the air. Two reasons
+for this are that power flight is a real conquest of the air, a real
+victory over the battling elements; secondly, because the aeroplane, or
+any flying machine that may follow, brings air travel within the reach
+of everybody. In practical development, the dirigible may be the
+steamship of the air, which will render invaluable services of a certain
+kind, and the aeroplane will be the automobile of the air, to be used by
+the multitude, perhaps for as many purposes as the automobile is now
+being used.
+
+
+ESSENTIAL REQUIREMENTS OF AERIAL MOTORS
+
+One of the marked features of aircraft development has been the effect
+it has had upon the refinement and perfection of the internal combustion
+motor. Without question gasoline-motors intended for aircraft are the
+nearest to perfection of any other type yet evolved. Because of the
+peculiar demands imposed upon the aeronautical motor it must possess all
+the features of reliability, economy and efficiency now present with
+automobile or marine engines and then must have distinctive points of
+its own. Owing to the unstable nature of the medium through which it is
+operated and the fact that heavier-than-air machines can maintain flight
+only as long as the power plant is functioning properly, an airship
+motor must be more reliable than any used on either land or water. While
+a few pounds of metal more or less makes practically no difference in a
+marine motor and has very little effect upon the speed or hill-climbing
+ability of an automobile, an airship motor must be as light as it is
+possible to make it because every pound counts, whether the motor is to
+be fitted into an aeroplane or in a dirigible balloon.
+
+Airship motors, as a rule, must operate constantly at high speeds in
+order to obtain a maximum power delivery with a minimum piston
+displacement. In automobiles, or motor boats, motors are not required to
+run constantly at their maximum speed. Most aircraft motors must
+function for extended periods at speed as nearly the maximum as
+possible. Another thing that militates against the aircraft motor is the
+more or less unsteady foundation to which it is attached. The
+necessarily light framework of the aeroplane makes it hard for a motor
+to perform at maximum efficiency on account of the vibration of its
+foundation while the craft is in flight. Marine and motor car engines,
+while not placed on foundations as firm as those provided for stationary
+power plants, are installed on bases of much more stability than the
+light structure of an aeroplane. The aircraft motor, therefore, must be
+balanced to a nicety and must run steadily under the most unfavorable
+conditions.
+
+
+AERIAL MOTORS MUST BE LIGHT
+
+The capacity of light motors designed for aerial work per unit of mass
+is surprising to those not fully conversant with the possibilities that
+a thorough knowledge of proportions of parts and the use of special
+metals developed by the automobile industry make possible. Activity in
+the development of light motors has been more pronounced in France than
+in any other country. Some of these motors have been complicated types
+made light by the skillful proportioning of parts, others are of the
+refined simpler form modified from current automobile practice. There is
+a tendency to depart from the freakish or unconventional construction
+and to adhere more closely to standard forms because it is necessary to
+have the parts of such size that every quality making for reliability,
+efficiency and endurance are incorporated in the design. Aeroplane
+motors range from two cylinders to forms having fourteen and sixteen
+cylinders and the arrangement of these members varies from the
+conventional vertical tandem and opposed placing to the V form or the
+more unusual radial motors having either fixed or rotary cylinders. The
+weight has been reduced so it is possible to obtain a complete power
+plant of the revolving cylinder air-cooled type that will not weigh more
+than three pounds per actual horse-power and in some cases less than
+this.
+
+If we give brief consideration to the requirements of the aviator it
+will be evident that one of the most important is securing maximum power
+with minimum mass, and it is desirable to conserve all of the good
+qualities existing in standard automobile motors. These are certainty of
+operation, good mechanical balance and uniform delivery of
+power--fundamental conditions which must be attained before a power
+plant can be considered practical. There are in addition, secondary
+considerations, none the less desirable, if not absolutely essential.
+These are minimum consumption of fuel and lubricating oil, which is
+really a factor of import, for upon the economy depends the capacity and
+flying radius. As the amount of liquid fuel must be limited the most
+suitable motor will be that which is powerful and at the same time
+economical. Another important feature is to secure accessibility of
+components in order to make easy repair or adjustment of parts possible.
+It is possible to obtain sufficiently light-weight motors without
+radical departure from established practice. Water-cooled power plants
+have been designed that will weigh but four or five pounds per
+horse-power and in these forms we have a practical power plant capable
+of extended operation.
+
+
+FACTORS INFLUENCING POWER NEEDED
+
+Work is performed whenever an object is moved against a resistance, and
+the amount of work performed depends not only on the amount of
+resistance overcome but also upon the amount of time utilized in
+accomplishing a given task. Work is measured in horse-power for
+convenience. It will take one horse-power to move 33,000 pounds one foot
+in one minute or 550 pounds one foot in one second. The same work would
+be done if 330 pounds were moved 100 feet in one minute. It requires a
+definite amount of power to move a vehicle over the ground at a certain
+speed, so it must take power to overcome resistance of an airplane in
+the air. Disregarding the factor of air density, it will take more power
+as the speed increases if the weight or resistance remains constant, or
+more power if the speed remains constant and the resistance increases.
+The airplane is supported by air reaction under the planes or lifting
+surfaces and the value of this reaction depends upon the shape of the
+aerofoil, the amount it is tilted and the speed at which it is drawn
+through the air. The angle of incidence or degree of wing tilt regulates
+the power required to a certain degree as this affects the speed of
+horizontal flight as well as the resistance. Resistance may be of two
+kinds, one that is necessary and the other that it is desirable to
+reduce to the lowest point possible. There is the wing resistance and
+the sum of the resistances of the rest of the machine such as fuselage,
+struts, wires, landing gear, etc. If we assume that a certain airplane
+offered a total resistance of 300 pounds and we wished to drive it
+through the air at a speed of sixty miles per hour, we can find the
+horse-power needed by a very simple computation as follows:
+
+ The product of 300 pounds resistance times speed of
+ 88 feet per second times 60 seconds in a minute
+ ----------------------------------------------------- = H.P. needed.
+ divided by 33,000 foot pounds per minute
+ in one horse-power
+
+The result is the horse-power needed, or
+
+ 300 x 88 x 60
+ --------------- = 48 H.P.
+ 33,000
+
+Just as it takes more power to climb a hill than it does to run a car on
+the level, it takes more power to climb in the air with an airplane than
+it does to fly on the level. The more rapid the climb, the more power it
+will take. If the resistance remains 300 pounds and it is necessary to
+drive the plane at 90 miles per hour, we merely substitute proper values
+in the above formula and we have
+
+ 300 pounds times 132 feet per second times 60
+ seconds in a minute
+ ----------------------------------------------- = 72 H.P.
+ 33,000 foot pounds per minute in one
+ horse-power
+
+The same results can be obtained by dividing the product of the
+resistance in pounds times speed in feet per second by 550, which is the
+foot-pounds of work done in one second to equal one horse-power.
+Naturally, the amount of propeller thrust measured in pounds necessary
+to drive an airplane must be greater than the resistance by a
+substantial margin if the plane is to fly and climb as well. The
+following formulae were given in "The Aeroplane" of London and can be
+used to advantage by those desiring to make computations to ascertain
+power requirements:
+
+[Illustration: Fig. 1.--Diagrams Illustrating Computations for
+Horse-Power Required for Airplane Flight.]
+
+The thrust of the propeller depends on the power of the motor, and on
+the diameter and pitch of the propeller. If the required thrust to a
+certain machine is known, the calculation for the horse-power of the
+motor should be an easy matter.
+
+The required thrust is the sum of three different "resistances." The
+first is the "drift" (dynamical head resistance of the aerofoils), i.e.,
+tan [alpha] x lift (_L_), lift being equal to the total weight of
+machine (_W_) for horizontal flight and [alpha] equal to the angle of
+incidence. Certainly we must take the tan [alpha] at the maximum _K_{y}_
+value for minimum speed, as then the drift is the greatest (Fig. 1, A).
+
+Another method for finding the drift is _D_ = _K_ x _AV_^{2}, when we
+take the drift again so as to be greatest.
+
+The second "resistance" is the total head resistance of the machine, at
+its maximum velocity. And the third is the thrust for climbing. The
+horse-power for climbing can be found out in two different ways. I first
+propose to deal with the method, where we find out the actual
+horse-power wanted for a certain climbing speed to our machine, where
+
+ climbing speed/sec. x _W_
+ H.P. = ---------------------------
+ 550
+
+In this case we know already the horse-power for climbing, and we can
+proceed with our calculation.
+
+With the other method we shall find out the "thrust" in pounds or
+kilograms wanted for climbing and add it to drift and total head
+resistance, and we shall have the total "thrust" of our machine and we
+shall denote it with _T_, while thrust for climbing shall be _T_{c}_.
+
+The following calculation is at our service to find out
+
+ _V_{c}_ x _W_
+ this thrust for climbing --------------- = H.P.,
+ 550
+
+ H.P. x 550
+ thence _V_{c}_ = ------------ (1)
+ _W_
+
+ _T_{c}_ x _V_
+ H.P. = --------------, then from
+ 550
+
+ _T_{c}_ x _V_
+ --------------- x 550
+ 550 _T_{c}_ x _V_
+ (1) _V_{c}_ = ----------------------- = ---------------, thence,
+ _W_ _W_
+
+ _V_{c}_ x _W_
+ T_{c} = ---------------.
+ _V_
+
+Whether _T_ means drifts, head resistance and thrust for climbing, or
+drift and head resistance only, the following calculation is the same,
+only in the latter case, of course, we must add the horse-power required
+for climbing to the result to obtain the total horse-power.
+
+Now, when we know the total thrust, we shall find the horse-power in the
+following manner:
+
+ _Pr_2[pi]_R_
+ We know that the H.P. = -------------- in kilograms, or in
+ 75 x 60
+
+ _Pr_2[pi]_R_
+ English measure, H.P. = -------------- (Fig. 1, B)
+ 33,000
+
+ where _P_ = pressure in klgs. or lbs.
+ _r_ = radius on which _P_ is acting.
+ _R_ = Revolution/min.
+
+ _M.R._2[pi]
+ When _P_ x _r_ = _M_, then H.P. = -------------, thence,
+ 4,500
+
+ H.P. x 4,500 716.2 H.P.
+ _M_ = -------------- = ------------ in meter kilograms,
+ _R_2[pi] _R_
+
+ H.P. 33,000 5253.1 H.P.
+ or in English system _M_ = ------------- = ------------- in
+ _R_2[pi] _R_
+
+foot pounds.
+
+Now the power on the circumference of the propeller will be reduced by
+its radius, so it will be _M_/_r_ = _p_. A part of _p_ will be used for
+counteracting the air and bearing friction, so that the total power on
+the circumference of the propeller will be (_M_/_r_) x [eta] = _p_ where
+[eta] is the mechanical efficiency of the propeller. Now
+
+ [eta]
+ --------------- = _T_, where [alpha] is taken on the tip of the
+ _tan_ [alpha]
+
+propeller.
+
+I take [alpha] at the tip, but it can be taken, of course, at any point,
+but then in equation _p_ = _M_/_r_, _r_ must be taken only up to this
+point, and not the whole radius; but it is more comfortable to take it
+at the tip, as
+
+ Pitch
+ _tan_ [alpha] = ---------- (Fig. 1, C).
+ _r_2[pi]
+
+Now we can write up the equation of the thrust:
+
+ 716.2 H.P. [eta] 5253.1 H.P. [eta]
+ -------------------, or in English measure -------------------
+ _R r tan [alpha]_ _R r tan [alpha]_
+
+ _T_ x _R_ x _r tan_ [alpha]
+ thence H.P. = -----------------------------, or in English measure
+ 716.2[eta]
+
+ _T_ x _R_ x _r tan_ [alpha]
+ -----------------------------.
+ 5253.1[eta]
+
+The computations and formulae given are of most value to the student
+engineer rather than matters of general interest, but are given so that
+a general idea may be secured of how airplane design influences power
+needed to secure sustained flight. It will be apparent that the
+resistance of an airplane depends upon numerous considerations of design
+which require considerable research in aerodynamics to determine
+accurately. It is obvious that the more resistance there is, the more
+power needed to fly at a given speed. Light monoplanes have been flown
+with as little as 15 horse-power for short distances, but most planes
+now built use engines of 100 horse-power or more. Giant airplanes have
+been constructed having 2,000 horse-power distributed in four power
+units. The amount of power provided for an airplane of given design
+varies widely as many conditions govern this, but it will range from
+approximately one horse-power to each 8 pounds weight in the case of
+very light, fast machines to one horse-power to 15 or 18 pounds of the
+total weight in the case of medium speed machines. The development in
+airplane and power plant design is so rapid, however, that the figures
+given can be considered only in the light of general averages rather
+than being typical of current practice.
+
+
+WHY EXPLOSIVE MOTORS ARE BEST
+
+Internal combustion engines are best for airplanes and all types of
+aircraft for the same reasons that they are universally used as a source
+of power for automobiles. The gasoline engine is the lightest known form
+of prime mover and a more efficient one than a steam engine, especially
+in the small powers used for airplane propulsion. It has been stated
+that by very careful designing a steam plant an engine could be made
+that would be practical for airplane propulsion, but even with the
+latest development it is doubtful if steam power can be utilized in
+aircraft to as good advantage as modern gasoline-engines are. While the
+steam-engine is considered very much simpler than a gas-motor, the
+latter is much more easily mastered by the non-technical aviator and
+certainly requires less attention. A weight of 10 pounds per horse-power
+is possible in a condensing steam plant but this figure is nearly double
+or triple what is easily secured with a gas-motor which may weigh but 5
+pounds per horse-power in the water cooled forms and but 2 or 3 pounds
+in the air-cooled types. The fuel consumption is twice as great in a
+steam-power plant (owing to heat losses) as would be the case in a
+gasoline engine of equal power and much less weight.
+
+The internal-combustion engine has come seemingly like an avalanche of a
+decade; but it has come to stay, to take its well-deserved position
+among the powers for aiding labor. Its ready adaptation to road, aerial
+and marine service has made it a wonder of the age in the development of
+speed not before dreamed of as a possibility; yet in so short a time,
+its power for speed has taken rank on the common road against the
+locomotive on the rail with its century's progress. It has made aerial
+navigation possible and practical, it furnishes power for all marine
+craft from the light canoe to the transatlantic liner. It operates the
+machine tools of the mechanic, tills the soil for the farmer and
+provides healthful recreation for thousands by furnishing an economical
+means of transport by land and sea. It has been a universal mechanical
+education for the masses, and in its present forms represents the great
+refinement and development made possible by the concentration of the
+world's master minds on the problems incidental to internal combustion
+engineering.
+
+
+HISTORICAL
+
+Although the ideal principle of explosive power was conceived some two
+hundred years ago, at which time experiments were made with gunpowder as
+the explosive element, it was not until the last years of the eighteenth
+century that the idea took a patentable shape, and not until about 1826
+(Brown's gas-vacuum engine) that a further progress was made in England
+by condensing the products of combustion by a jet of water, thus
+creating a partial vacuum.
+
+Brown's was probably the first explosive engine that did real work. It
+was clumsy and unwieldy and was soon relegated to its place among the
+failures of previous experiments. No approach to active explosive effect
+in a cylinder was reached in practice, although many ingenious designs
+were described, until about 1838 and the following years. Barnett's
+engine in England was the first attempt to compress the charge before
+exploding. From this time on to about 1860 many patents were issued in
+Europe and a few in the United States for gas-engines, but the progress
+was slow, and its practical introduction for power came with spasmodic
+effect and low efficiency. From 1860 on, practical improvement seems to
+have been made, and the Lenoir motor was produced in France and brought
+to the United States. It failed to meet expectations, and was soon
+followed by further improvements in the Hugon motor in France (1862),
+followed by Beau de Rocha's four-cycle idea, which has been slowly
+developed through a long series of experimental trials by different
+inventors. In the hands of Otto and Langdon a further progress was made,
+and numerous patents were issued in England, France, and Germany, and
+followed up by an increasing interest in the United States, with a few
+patents.
+
+From 1870 improvements seem to have advanced at a steady rate, and
+largely in the valve-gear and precision of governing for variable load.
+The early idea of the necessity of slow combustion was a great drawback
+in the advancement of efficiency, and the suggestion of de Rocha in 1862
+did not take root as a prophetic truth until many failures and years of
+experience had taught the fundamental axiom that rapidity of action in
+both combustion and expansion was the basis of success in explosive
+motors.
+
+With this truth and the demand for small and safe prime movers, the
+manufacture of gas-engines increased in Europe and America at a more
+rapid rate, and improvements in perfecting the details of this cheap and
+efficient prime mover have finally raised it to the dignity of a
+standard motor and a dangerous rival of the steam-engine for small and
+intermediate powers, with a prospect of largely increasing its
+individual units to many hundred, if not to the thousand horse-power in
+a single cylinder. The unit size in a single cylinder has now reached to
+about 700 horse-power and by combining cylinders in the same machine,
+powers of from 1,500 to 2,000 horse-power are now available for large
+power-plants.
+
+
+MAIN TYPES OF INTERNAL-COMBUSTION ENGINES
+
+This form of prime mover has been built in so many different types, all
+of which have operated with some degree of success that the diversity in
+form will not be generally appreciated unless some attempt is made to
+classify the various designs that have received practical application.
+Obviously the same type of engine is not universally applicable, because
+each class of work has individual peculiarities which can best be met by
+an engine designed with the peculiar conditions present in view. The
+following tabular synopsis will enable the reader to judge the extent of
+the development of what is now the most popular prime mover for all
+purposes.
+
+ A. Internal Combustion (Standard Type)
+ 1. Single Acting (Standard Type)
+ 2. Double Acting (For Large Power Only)
+ 3. Simple (Universal Form)
+ 4. Compound (Rarely Used)
+ 5. Reciprocating Piston (Standard Type)
+ 6. Turbine (Revolving Rotor, not fully developed)
+
+ A1. Two-Stroke Cycle
+ a. Two Port
+ b. Three Port
+ c. Combined Two and Three Port
+ d. Fourth Port Accelerator
+ e. Differential Piston Type
+ f. Distributor Valve System
+
+ A2. Four-Stroke Cycle
+ a. Automatic Inlet Valve
+ b. Mechanical Inlet Valve
+ c. Poppet or Mushroom Valve
+ d. Slide Valve
+ d 1. Sleeve Valve
+ d 2. Reciprocating Ring Valve
+ d 3. Piston Valve
+ e. Rotary Valves
+ e 1. Disc
+ e 2. Cylinder or Barrel
+ e 3. Single Cone
+ e 4. Double Cone
+ f. Two Piston (Balanced Explosion)
+ g. Rotary Cylinder, Fixed Crank (Aerial)
+ h. Fixed Cylinder, Rotary Crank (Standard Type)
+
+ A3. Six-Stroke Cycle
+
+ B. External Combustion (Practically Obsolete)
+ a. Turbine, Revolving Rotor
+ b. Reciprocating Piston
+
+
+CLASSIFICATION BY CYLINDER ARRANGEMENT
+
+ Single Cylinder
+ a. Vertical
+ b. Horizontal
+ c. Inverted Vertical
+
+ Double Cylinder
+ a. Vertical
+ b. Horizontal (Side by Side)
+ c. Horizontal (Opposed)
+ d. 45 to 90 Degrees V (Angularly Disposed)
+ e. Horizontal Tandem (Double Acting)
+
+ Three Cylinder
+ a. Vertical
+ b. Horizontal
+ c. Rotary (Cylinders Spaced at 120 Degrees)
+ d. Radially Placed (Stationary Cylinders)
+ e. One Vertical, One Each Side at an Angle
+ f. Compound (Two High Pressure, One Low Pressure)
+
+ Four Cylinder
+ a. Vertical
+ b. Horizontal (Side by Side)
+ c. Horizontal (Two Pairs Opposed)
+ d. 45 to 90 Degrees V
+ e. Twin Tandem (Double Acting)
+
+ Five Cylinder
+ a. Vertical (Five Throw Crankshaft)
+ b. Radially Spaced at 72 Degrees (Stationary)
+ c. Radially Placed Above Crankshaft (Stationary)
+ d. Placed Around Rotary Crankcase (72 Degrees Spacing)
+
+ Six Cylinder
+ a. Vertical
+ b. Horizontal (Three Pairs Opposed)
+ c. 45 to 90 Degrees V
+
+ Seven Cylinder
+ a. Equally Spaced (Rotary)
+
+ Eight Cylinder
+ a. Vertical
+ b. Horizontal (Four Pairs Opposed)
+ c. 45 to 90 Degrees V
+
+ Nine Cylinder
+ a. Equally Spaced (Rotary)
+
+ Twelve Cylinder
+ a. Vertical
+ b. Horizontal (Six Pairs Opposed)
+ c. 45 to 90 Degrees V
+
+ Fourteen Cylinder
+ a. Rotary
+
+ Sixteen Cylinder
+ a. 45 to 90 Degrees V
+ b. Horizontal (Eight Pairs Opposed)
+
+ Eighteen Cylinder
+ a. Rotary Cylinder
+
+[Illustration: Fig. 2.--Plate Showing Heavy, Slow Speed Internal
+Combustion Engines Used Only for Stationary Power in Large Installations
+Giving Weight to Horse-Power Ratio.]
+
+[Illustration: Fig. 3.--Various Forms of Internal Combustion Engines
+Showing Decrease in Weight to Horse-Power Ratio with Augmenting Speed of
+Rotation.]
+
+[Illustration: Fig. 4.--Internal Combustion Engine Types of Extremely
+Fine Construction and Refined Design, Showing Great Power Outputs for
+Very Small Weight, a Feature Very Much Desired in Airplane Power
+Plants.]
+
+Of all the types enumerated above engines having less than eight
+cylinders are the most popular in everything but aircraft work. The
+four-cylinder vertical is without doubt the most widely used of all
+types owing to the large number employed as automobile power plants.
+Stationary engines in small and medium powers are invariably of the
+single or double form. Three-cylinder engines are seldom used at the
+present time, except in marine work and in some stationary forms.
+Eight- and twelve-cylinder motors have received but limited application
+and practically always in automobiles, racing motor boats or in aircraft.
+The only example of a fourteen-cylinder motor to be used to any extent
+is incorporated in aeroplane construction. This is also true of the
+sixteen- and eighteen-cylinder forms and of twenty-four-cylinder engines
+now in process of development.
+
+The duty an engine is designed for determines the weight per
+horse-power. High powered engines intended for steady service are always
+of the slow speed type and consequently are of very massive
+construction. Various forms of heavy duty type stationary engines are
+shown at Fig. 2. Some of these engines may weigh as much as 600 pounds
+per horse-power. A further study is possible by consulting data given on
+Figs. 3 and 4. As the crank-shaft speed increases and cylinders are
+multiplied the engines become lighter. While the big stationary power
+plants may run for years without attention, airplane engines require
+rebuilding after about 60 to 80 hours air service for the fixed cylinder
+types and 40 hours or less for the rotary cylinder air-cooled forms.
+There is evidently a decrease in durability and reliability as the
+weight is lessened. These illustrations also permit of obtaining a good
+idea of the variety of forms internal combustion engines are made in.
+
+
+
+
+CHAPTER II
+
+ Operating Principles of Two- and Four-Stroke Engines--Four-cycle
+ Action--Two-cycle Action--Comparing Two- and Four-cycle Types--
+ Theory of Gas and Gasoline Engine--Early Gas-Engine Forms--
+ Isothermal Law--Adiabatic Law--Temperature Computations--Heat
+ and Its Work--Conversion of Heat to Power--Requisites for Best
+ Power Effect.
+
+
+OPERATING PRINCIPLES OF TWO- AND FOUR-STROKE CYCLE ENGINES
+
+Before discussing the construction of the various forms of internal
+combustion engines it may be well to describe the operating cycle of the
+types most generally used. The two-cycle engine is the simplest because
+there are no valves in connection with the cylinder, as the gas is
+introduced into that member and expelled from it through ports cored
+into the cylinder walls. These are covered by the piston at a certain
+portion of its travel and uncovered at other parts of its stroke. In the
+four-cycle engine the explosive gas is admitted to the cylinder through
+a port at the head end closed by a valve, while the exhaust gas is
+expelled through another port controlled in a similar manner. These
+valves are operated by mechanism distinct from the piston.
+
+[Illustration: Fig. 5.--Outlining First Two Strokes of Piston in
+Four-Cycle Engine.]
+
+The action of the four-cycle type may be easily understood if one refers
+to illustrations at Figs. 5 and 6. It is called the "four-stroke engine"
+because the piston must make four strokes in the cylinder for each
+explosion or power impulse obtained. The principle of the gas-engine of
+the internal combustion type is similar to that of a gun, i.e., power is
+obtained by the rapid combustion of some explosive or other quick
+burning substance. The bullet is driven out of the gun barrel by the
+pressure of the gas evolved when the charge of powder is ignited. The
+piston or movable element of the gas-engine is driven from the closed
+or head end to the crank end of the cylinder by a similar expansion of
+gases resulting from combustion. The first operation in firing a gun or
+securing an explosion in the cylinder of the gas-engine is to fill the
+combustion space with combustible material. This is done by a down
+stroke of the piston during which time the inlet valve opens to admit
+the gaseous charge to the cylinder interior. This operation is shown at
+Fig. 5, A. The second operation is to compress this gas which is done by
+an upward stroke of the piston as shown at Fig. 5, B. When the top of
+the compression stroke is reached, the gas is ignited and the piston is
+driven down toward the open end of the cylinder, as indicated at Fig. 6,
+C. The fourth operation or exhaust stroke is performed by the return
+upward movement of the piston as shown at Fig. 6, D during which time
+the exhaust valve is opened to permit the burnt gases to leave the
+cylinder. As soon as the piston reaches the top of its exhaust stroke,
+the energy stored in the fly-wheel rim during the power stroke causes
+that member to continue revolving and as the piston again travels on
+its down stroke the inlet valve opens and admits a charge of fresh gas
+and the cycle of operations is repeated.
+
+[Illustration: Fig. 6.--Outlining Second Two Strokes of Piston in
+Four-Cycle Engine.]
+
+[Illustration: Fig. 7.--Sectional View of L Head Gasoline Engine
+Cylinder Showing Piston Movements During Four-Stroke Cycle.]
+
+The illustrations at Fig. 7 show how the various cycle functions take
+place in an L head type water cooled cylinder engine. The sections at A
+and C are taken through the inlet valve, those at B and D are taken
+through the exhaust valve.
+
+The two-cycle engine works on a different principle, as while only the
+combustion chamber end of the piston is employed to do useful work in
+the four-cycle engine, both upper and lower portions are called upon to
+perform the functions necessary to two-cycle engine operation. Instead
+of the gas being admitted into the cylinder as is the case with the
+four-stroke engine, it is first drawn into the engine base where it
+receives a preliminary compression prior to its transfer to the working
+end of the cylinder. The views at Fig. 8 should indicate clearly the
+operation of the two-port two-cycle engine. At A the piston is seen
+reaching the top of its stroke and the gas above the piston is being
+compressed ready for ignition, while the suction in the engine base
+causes the automatic valve to open and admits mixture from the
+carburetor to the crank case. When the piston reaches the top of its
+stroke, the compressed gas is ignited and the piston is driven down on
+the power stroke, compressing the gas in the engine base.
+
+[Illustration: Fig. 8.--Showing Two-port, Two-cycle Engine Operation.]
+
+When the top of the piston uncovers the exhaust port the flaming gas
+escapes because of its pressure. A downward movement of the piston
+uncovers the inlet port opposite the exhaust and permits the fresh gas
+to bypass through the transfer passage from the engine base to the
+cylinder. The conditions with the intake and exhaust port fully opened
+are clearly shown at Fig. 8, C. The deflector plate on the top of the
+piston directs the entering fresh gas to the top of the cylinder and
+prevents the main portion of the gas stream from flowing out through the
+open exhaust port. On the next upstroke of the piston the gas in the
+cylinder is compressed and the inlet valve opened, as shown at A to
+permit a fresh charge to enter the engine base.
+
+[Illustration: Fig. 9.--Defining Three-port, Two-cycle Engine Action.]
+
+The operating principle of the three-port, two-cycle engine is
+practically the same as that previously described with the exception
+that the gas is admitted to the crank-case through a third port in the
+cylinder wall, which is uncovered by the piston when that member reaches
+the end of its upstroke. The action of the three-port form can be
+readily ascertained by studying the diagrams given at Fig. 9.
+Combination two- and three-port engines have been evolved and other
+modifications made to improve the action.
+
+
+THE TWO-CYCLE AND FOUR-CYCLE TYPES
+
+In the earlier years of explosive-motor progress was evolved the two
+types of motors in regard to the cycles of their operation. The early
+attempts to perfect the two-cycle principle were for many years held in
+abeyance from the pressure of interests in the four-cycle type, until
+its simplicity and power possibilities were demonstrated by Mr. Dugald
+Clerk in England, who gave the principles of the two-cycle motor a broad
+bearing leading to immediate improvements in design, which has made
+further progress in the United States, until at the present time it has
+an equal standard value as a motor-power in some applications as its
+ancient rival the four-cycle or Otto type, as demonstrated by Beau de
+Rocha in 1862.
+
+Thermodynamically, the methods of the two types are equal as far as
+combustion is concerned, and compression may favor in a small degree the
+four-cycle type as well as the purity of the charge. The cylinder volume
+of the two-cycle motor is much smaller per unit of power, and the
+enveloping cylinder surface is therefore greater per unit of volume.
+Hence more heat is carried off by the jacket water during compression,
+and the higher compression available from this tends to increase the
+economy during compression which is lost during expansion.
+
+From the above considerations it may be safely stated that a _lower_
+temperature and higher pressure of charge at the beginning of
+compression is obtained in the two-cycle motor, greater weight of charge
+and greater specific power of higher compression resulting in higher
+thermal efficiency. The smaller cylinder for the same power of the
+two-cycle motor gives less friction surface per impulse than of the
+other type; although the crank-chamber pressure may, in a measure,
+balance the friction of the four-cycle type. Probably the strongest
+points in favor of the two-cycle type are the lighter fly-wheel and the
+absence of valves and valve gear, making this type the most simple in
+construction and the lightest in weight for its developed power. Yet,
+for the larger power units, the four-cycle type will no doubt always
+maintain the standard for efficiency and durability of action.
+
+The distribution of the charge and its degree of mixture with the
+remains of the previous explosion in the clearance space, has been a
+matter of discussion for both types of explosive motors, with doubtful
+results. In Fig. 10, A we illustrate what theory suggests as to the
+distribution of the fresh charge in a two-cycle motor, and in Fig. 10, B
+what is the probable distribution of the mixture when the piston starts
+on its compressive stroke. The arrows show the probable direction of
+flow of the fresh charge and burnt gases at the crucial moment.
+
+[Illustration: Fig. 10.--Diagrams Contrasting Action of Two- and
+Four-Cycle Cylinders on Exhaust and Intake Stroke.]
+
+In Fig. 10, C is shown the complete out-sweep of the products of
+combustion for the full extent of the piston stroke of a four-cycle
+motor, leaving only the volume of the clearance to mix with the new
+charge and at D the manner by which the new charge sweeps by the
+ignition device, keeping it cool and avoiding possibilities of
+pre-ignition by undue heating of the terminals of the sparking device.
+Thus, by enveloping the sparking device with the pure mixture, ignition
+spreads through the charge with its greatest possible velocity, a most
+desirable condition in high-speed motors with side-valve chambers and
+igniters within the valve chamber.
+
+
+THEORY OF THE GAS AND GASOLINE ENGINE
+
+The laws controlling the elements that create a power by their expansion
+by heat due to combustion, when properly understood, become a matter of
+computation in regard to their value as an agent for generating power in
+the various kinds of explosive engines. The method of heating the
+elements of power in explosive engines greatly widens the limits of
+temperature as available in other types of heat-engines. It disposes of
+many of the practical troubles of hot-air, and even of steam-engines, in
+the simplicity and directness of application of the elements of power.
+In the explosive engine the difficulty of conveying heat for producing
+expansive effect by convection is displaced by the generation of the
+required heat within the expansive element and at the instant of its
+useful work. The low conductivity of heat to and from air has been the
+great obstacle in the practical development of the hot-air engine;
+while, on the contrary, it has become the source of economy and
+practicability in the development of the internal-combustion engine.
+
+The action of air, gas, and the vapors of gasoline and petroleum oil,
+whether singly or mixed, is affected by changes of temperature
+practically in nearly the same ratio; but when the elements that produce
+combustion are interchanged in confined spaces, there is a marked
+difference of effect. The oxygen of the air, the hydrogen and carbon of
+a gas, or vapor of gasoline or petroleum oil are the elements that by
+combustion produce heat to expand the nitrogen of the air and the watery
+vapor produced by the union of the oxygen in the air and the hydrogen in
+the gas, as well as also the monoxide and carbonic-acid gas that may be
+formed by the union of the carbon of gas or vapor with part of the
+oxygen of the air. The various mixtures as between air and gas, or air
+and vapor, with the proportion of the products of combustion left in the
+cylinder from a previous combustion, form the elements to be considered
+in estimating the amount of pressure that may be obtained by their
+combustion and expansive force.
+
+
+EARLY GAS ENGINE FORMS
+
+The working process of the explosive motor may be divided into three
+principal types: 1. Motors with charges igniting at constant volume
+without compression, such as the Lenoir, Hugon, and other similar types
+now abandoned as wasteful in fuel and effect. 2. Motors with charges
+igniting at constant pressure with compression, in which a receiver is
+charged by a pump and the gases burned while being admitted to the motor
+cylinder, such as types of the Simon and Brayton engine. 3. Motors with
+charges igniting at constant volume with variable compression, such as
+the later two- and four-cycle motors with compression of the indrawn
+charge; limited in the two-cycle type and variable in the four-cycle
+type with the ratios of the clearance space in the cylinder. This
+principle produces the explosive motor of greatest efficiency.
+
+The phenomena of the brilliant light and its accompanying heat at the
+moment of explosion have been witnessed in the experiments of Dugald
+Clerk in England, the illumination lasting throughout the stroke; but in
+regard to time in a four-cycle engine, the incandescent state exists
+only one-quarter of the running time. Thus the time interval, together
+with the non-conductibility of the gases, makes the phenomena of a
+high-temperature combustion within the comparatively cool walls of a
+cylinder a practical possibility.
+
+
+THE ISOTHERMAL LAW
+
+The natural laws, long since promulgated by Boyle, Gay Lussac, and
+others, on the subject of the expansion and compression of gases by
+force and by heat, and their variable pressures and temperatures when
+confined, are conceded to be practically true and applicable to all
+gases, whether single, mixed, or combined.
+
+The law formulated by Boyle only relates to the compression and
+expansion of gases without a change of temperature, and is stated in
+these words:
+
+_If the temperature of a gas be kept constant, its pressure or elastic
+force will vary inversely as the volume it occupies._
+
+It is expressed in the formula P x V = C, or pressure x volume =
+constant. Hence, C/P = V and C/V = P.
+
+Thus the curve formed by increments of pressure during the expansion or
+compression of a given volume of gas without change of temperature is
+designated as the isothermal curve in which the volume multiplied by the
+pressure is a constant value in expansion, and inversely the pressure
+divided by the volume is a constant value in compressing a gas.
+
+But as compression and expansion of gases require force for their
+accomplishment mechanically, or by the application or abstraction of
+heat chemically, or by convection, a second condition becomes involved,
+which was formulated into a law of thermodynamics by Gay Lussac under
+the following conditions: A given volume of gas under a free piston
+expands by heat and contracts by the loss of heat, its volume causing a
+proportional movement of a free piston equal to 1/273 part of the
+cylinder volume for each degree Centigrade difference in temperature, or
+1/492 part of its volume for each degree Fahrenheit. With a fixed piston
+(constant volume), the pressure is increased or decreased by an increase
+or decrease of heat in the same proportion of 1/273 part of its pressure
+for each degree Centigrade, or 1/492 part of its pressure for each
+degree Fahrenheit change in temperature. This is the natural sequence of
+the law of mechanical equivalent, which is a necessary deduction from
+the principle that nothing in nature can be lost or wasted, for all the
+heat that is imparted to or abstracted from a gaseous body must be
+accounted for, either as heat or its equivalent transformed into some
+other form of energy. In the case of a piston moving in a cylinder by
+the expansive force of heat in a gaseous body, all the heat expended in
+expansion of the gas is turned into work; the balance must be accounted
+for in absorption by the cylinder or radiation.
+
+
+THE ADIABATIC LAW
+
+This theory is equally applicable to the cooling of gases by abstraction
+of heat or by cooling due to expansion by the motion of a piston. The
+denominators of these heat fractions of expansion or contraction
+represent the absolute zero of cold below the freezing-point of water,
+and read -273 deg. C. or -492.66 deg. = -460.66 deg. F. below zero; and
+these are the starting-points of reference in computing the heat expansion
+in gas-engines. According to Boyle's law, called the first law of gases,
+there are but two characteristics of a gas and their variations to be
+considered, _viz_., volume and pressure: while by the law of Gay Lussac,
+called the second law of gases, a third is added, consisting of the
+value of the absolute temperature, counting from absolute zero to the
+temperatures at which the operations take place. This is the _Adiabatic_
+law.
+
+The ratio of the variation of the three conditions--volume, pressure,
+and heat--from the absolute zero temperature has a certain rate, in
+which the volume multiplied by the pressure and the product divided by
+the absolute temperature equals the ratio of expansion for each degree.
+If a volume of air is contained in a cylinder having a piston and fitted
+with an indicator, the piston, if moved to and fro slowly, will
+alternately compress and expand the air, and the indicator pencil will
+trace a line or lines upon the card, which lines register the change of
+pressure and volume occurring in the cylinder. If the piston is
+perfectly free from leakage, and it be supposed that the temperature of
+the air is kept quite constant, then the line so traced is called an
+_Isothermal line_, and the pressure at any point when multiplied by the
+volume is a constant, according to Boyle's law,
+
+ _pv_ = a constant.
+
+If, however, the piston is moved very rapidly, the air will not remain
+at constant temperature, but the temperature will increase because work
+has been done upon the air, and the heat has no time to escape by
+conduction. If no heat whatever is lost by any cause, the line will be
+traced over and over again by the indicator pencil, the cooling by
+expansion doing work precisely equalling the heating by compression.
+This is the line of no transmission of heat, therefore known as
+_Adiabatic_.
+
+[Illustration: Fig. 11.--Diagram Isothermal and Adiabatic Lines.]
+
+The expansion of a gas 1/273 of its volume for every degree Centigrade,
+added to its temperature, is equal to the decimal .00366, the
+coefficient of expansion for Centigrade units. To any given volume of a
+gas, its expansion may be computed by multiplying the coefficient by
+the number of degrees, and by reversing the process the degree of
+acquired heat may be obtained approximately. These methods are not
+strictly in conformity with the absolute mathematical formula, because
+there is a small increase in the increment of expansion of a dry gas,
+and there is also a slight difference in the increment of expansion due
+to moisture in the atmosphere and to the vapor of water formed by the
+union of the hydrogen and oxygen in the combustion chamber of explosive
+engines.
+
+
+TEMPERATURE COMPUTATIONS
+
+The ratio of expansion on the Fahrenheit scale is derived from the
+absolute temperature below the freezing-point of water (32 deg.) to
+correspond with the Centigrade scale; therefore 1/492.66 = .0020297, the
+ratio of expansion from 32 deg. for each degree rise in temperature on
+the Fahrenheit scale. As an example, if the temperature of any volume of
+air or gas at constant volume is raised, say from 60 deg. to 2000 deg.
+F., the increase in temperature will be 1940 deg.. The ratio will be
+1/520.66 = .0019206. Then by the formula:
+
+Ratio x acquired temp. x initial pressure = the gauge pressure; and
+.0019206 x 1940 deg. x 14.7 = 54.77 lbs.
+
+By another formula, a convenient ratio is obtained by (absolute
+pressure)/(absolute temp.) or 14.7/520.66 = .028233; then, using the
+difference of temperature as before, .028233 x 1940 deg. = 54.77 lbs.
+pressure.
+
+By another formula, leaving out a small increment due to specific heat
+at high temperatures:
+
+ Atmospheric pressure x absolute temp. + acquired temp.
+ I. -------------------------------------------------------- =
+ Absolute temp. + initial temp.
+
+absolute pressure due to the acquired temperature, from which the
+atmospheric pressure is deducted for the gauge pressure. Using the
+foregoing example, we have (14.7 x 460.66 deg. + 2000 deg.)/(460.66 +
+60 deg.) = 69.47 - 14.7 = 54.77, the gauge pressure, 460.66 being the
+absolute temperature for zero Fahrenheit.
+
+For obtaining the volume of expansion of a gas from a given increment of
+heat, we have the approximate formula:
+
+ Volume x absolute temp. + acquired temp.
+ II. ------------------------------------------ =
+ Absolute temp. + initial temp.
+
+heated volume. In applying this formula to the foregoing example, the
+figures become:
+
+ 460.66 deg. + 2000 deg.
+ I. x ------------------------- = 4.72604 volumes.
+ 460.66 + 60 deg.
+
+From this last term the gauge pressure may be obtained as follows:
+
+III. 4.72604 x 14.7 = 69.47 lbs. absolute - 14.7 lbs. atmospheric
+pressure = 54.77 lbs. gauge pressure; which is the theoretical pressure
+due to heating air in a confined space, or at constant volume from 60
+deg. to 2000 deg. F.
+
+By inversion of the heat formula for absolute pressure we have the
+formula for the acquired heat, derived from combustion at constant
+volume from atmospheric pressure to gauge pressure plus atmospheric
+pressure as derived from Example I., by which the expression
+
+ absolute pressure x absolute temp. + initial temp.
+ ----------------------------------------------------
+ initial absolute pressure
+
+= absolute temperature + temperature of combustion, from which the
+acquired temperature is obtained by subtracting the absolute
+temperature.
+
+Then, for example, (69.47 x 460.66 + 60)/14.7 = 2460.66, and 2460.66 -
+460.66 = 2000 deg., the theoretical heat of combustion. The dropping of
+terminal decimals makes a small decimal difference in the result in the
+different formulas.
+
+
+HEAT AND ITS WORK
+
+By Joule's law of the mechanical equivalent of heat, whenever heat is
+imparted to an elastic body, as air or gas, energy is generated and
+mechanical work produced by the expansion of the air or gas. When the
+heat is imparted by combustion within a cylinder containing a movable
+piston, the mechanical work becomes an amount measurable by the observed
+pressure and movement of the piston. The heat generated by the explosive
+elements and the expansion of the non-combining elements of nitrogen and
+water vapor that may have been injected into the cylinder as moisture in
+the air, and the water vapor formed by the union of the oxygen of the
+air with the hydrogen of the gas, all add to the energy of the work from
+their expansion by the heat of internal combustion. As against this, the
+absorption of heat by the walls of the cylinder, the piston, and
+cylinder-head or clearance walls, becomes a modifying condition in the
+force imparted to the moving piston.
+
+It is found that when any explosive mixture of air and gas or
+hydrocarbon vapor is fired, the pressure falls far short of the pressure
+computed from the theoretical effect of the heat produced, and from
+gauging the expansion of the contents of a cylinder. It is now well
+known that in practice the high efficiency which is promised by
+theoretical calculation is never realized; but it must always be
+remembered that the heat of combustion is the real agent, and that the
+gases and vapors are but the medium for the conversion of inert elements
+of power into the activity of energy by their chemical union. The theory
+of combustion has been the leading stimulus to large expectations with
+inventors and constructors of explosive motors; its entanglement with
+the modifying elements in practice has delayed the best development in
+construction, and as yet no really positive design of best form or
+action seems to have been accomplished, although great progress has been
+made during the past decade in the development of speed, reliability,
+economy, and power output of the individual units of this comparatively
+new power.
+
+One of the most serious difficulties in the practical development of
+pressure, due to the theoretical computations of the pressure value of
+the full heat, is probably caused by imparting the heat of the fresh
+charge to the balance of the previous charge that has been cooled by
+expansion from the maximum pressure to near the atmospheric pressure of
+the exhaust. The retardation in the velocity of combustion of perfectly
+mixed elements is now well known from experimental trials with measured
+quantities; but the principal difficulty in applying these conditions to
+the practical work of an explosive engine where a necessity for a large
+clearance space cannot be obviated, is in the inability to obtain a
+maximum effect from the imperfect mixture and the mingling of the
+products of the last explosion with the new mixture, which produces a
+clouded condition that makes the ignition of the mass irregular or
+chattering, as observed in the expansion lines of indicator cards; but
+this must not be confounded with the reaction of the spring in the
+indicator.
+
+Stratification of the mixture has been claimed as taking place in the
+clearance chamber of the cylinder; but this is not a satisfactory
+explanation in view of the vortical effect of the violent injection of
+the air and gas or vapor mixture. It certainly cannot become a perfect
+mixture in the time of a stroke of a high-speed motor of the two-cycle
+class. In a four-cycle engine, making 1,500 revolutions per minute, the
+injection and compression in any one cylinder take place in one
+twenty-fifth of a second--formerly considered far too short a time for a
+perfect infusion of the elements of combustion but now very easily taken
+care of despite the extremely high speed of numerous aviation and
+automobile power-plants.
+
+TABLE I.--EXPLOSION AT CONSTANT VOLUME IN A CLOSED CHAMBER.
+
+ =====+================================+======+=======+========+=========
+ Dia- | | Temp.| Time | Ob- | Com-
+ gram | | of | of | served |puted
+ Curve| Mixture Injected. |Injec-|Explo- | Gauge |Temp.
+ Fig. | | tion | sion |Pressure|Fahr.
+ 8. | | Fahr.|Second.| Pounds |
+ -----+--------------------------------+------+-------+--------+---------
+ _a_ |1 volume gas to 14 volumes air. |64 deg| 0.45 | 40. |1,483 deg.
+ _b_ |1 " " " 13 " " |51 deg| 0.31 | 51.5 |1,859 deg.
+ _c_ |1 " " " 12 " " |51 deg| 0.24 | 60. |2,195 deg.
+ _d_ |1 " " " 11 " " |51 deg| 0.17 | 61. |2,228 deg.
+ _e_ |1 " " " 9 " " |62 deg| 0.08 | 78. |2,835 deg.
+ _f_ |1 " " " 7 " " |62 deg| 0.06 | 87. |3,151 deg.
+ _g_ |1 " " " 6 " " |51 deg| 0.04 | 90. |3,257 deg.
+ _h_ |1 " " " 5 " " |51 deg| 0.055 | 91. |3,293 deg.
+ _i_ |1 " " " 4 " " |66 deg| 0.16 | 80. |2,871 deg.
+ -----+--------------------------------+------+-------+--------+---------
+
+In an examination of the times of explosion and the corresponding
+pressures in both tables, it will be seen that a mixture of 1 part gas
+to 6 parts air is the most effective and will give the highest mean
+pressure in a gas-engine. There is a limit to the relative proportions
+of illuminating gas and air mixture that is explosive, somewhat
+variable, depending upon the proportion of hydrogen in the gas. With
+ordinary coal-gas, 1 of gas to 15 parts of air; and on the lower end of
+the scale, 1 volume of gas to 2 parts air, are non-explosive. With
+gasoline vapor the explosive effect ceases at 1 to 16, and a saturated
+mixture of equal volumes of vapor and air will not explode, while the
+most intense explosive effect is from a mixture of 1 part vapor to 9
+parts air. In the use of gasoline and air mixtures from a carburetor,
+the best effect is from 1 part saturated air to 8 parts free air.
+
+TABLE II.--PROPERTIES AND EXPLOSIVE TEMPERATURE OF A MIXTURE OF ONE PART
+OF ILLUMINATING GAS OF 660 THERMAL UNITS PER CUBIC FOOT WITH VARIOUS
+PROPORTIONS OF AIR WITHOUT MIXTURE OF CHARGE WITH THE PRODUCTS OF A
+PREVIOUS EXPLOSION.
+
+ [A] Proportion, Air to Gas by Volumes.
+ [B] Pounds in One Cubic Foot of Mixture.
+ [C] Specific Heat. Heat Units Required to Raise 1 Lb. 1 Deg.
+ Fahrenheit. Constant Pressure.
+ [D] Specific Heat. Heat Units Required to Raise 1 Lb. 1 Deg.
+ Fahrenheit. Constant Volume.
+ [E] Heat to Raise One Cubic Foot of Mixture 1 Deg. Fahr.
+ [F] Heat Units Evolved by Combustion.
+ [G] Ratio Col. 6/5
+ [H] Usual Combustion Efficiency.
+ [I] Usual Rise of Temperature due to Explosion at Constant Volume.
+
+ =======+========+======+======+========+======+=======+=====+=====
+ [A] | [B] | [C] | [D] | [E] | [F] | [G] | [H] | [I]
+ -------+--------+------+------+--------+------+-------+-----+-----
+ 6 to 1| .074195| .2668| .1913| .014189| 94.28| 6644.6| .465| 3090
+ 7 to 1| .075012| .2628| .1882| .014116| 82. | 5844.4| .518| 3027
+ 8 to 1| .075647| .2598| .1858| .014059| 73.33| 5216.1| .543| 2832
+ 9 to 1| .076155| .2575| .1846| .014013| 66. | 4709.9| .56 | 2637
+ 10 to 1| .076571| .2555| .1825| .013976| 60. | 4293. | .575| 2468
+ 11 to 1| .076917| .2540| .1813| .013945| 55. | 3944. | .585| 2307
+ 12 to 1| .077211| .2526| .1803| .013922| 50.77| 3646.7| .58 | 2115
+ -------+--------+------+------+--------+------+-------+-----+-----
+
+The weight of a cubic foot of gas and air mixture as given in Col. 2 is
+found by adding the number of volumes of air multiplied by its weight,
+.0807, to one volume of gas of weight .035 pound per cubic foot and
+dividing by the total number of volumes; for example, as in the table, 6
+x .0807 = .5192/7 = .074195 as in the first line, and so on for any
+mixture or for other gases of different specific weight per cubic foot.
+The heat units evolved by combustion of the mixture (Col. 6) are
+obtained by dividing the total heat units in a cubic foot of gas by the
+total proportion of the mixture, 660/7 = 94.28 as in the first line of
+the table. Col. 5 is obtained by multiplying the weight of a cubic foot
+of the mixture in Col. 2 by the specific heat at a constant volume (Col.
+4), Col. 6/Col. 5 = Col. 7 the total heat ratio, of which Col. 8 gives
+the usual combustion efficiency--Col. 7 x Col. 8 gives the absolute rise
+in temperature of a pure mixture, as given in Col. 9.
+
+The many recorded experiments made to solve the discrepancy between the
+theoretical and the actual heat development and resulting pressures in
+the cylinder of an explosive motor, to which much discussion has been
+given as to the possibilities of dissociation and the increased specific
+heat of the elements of combustion and non-combustion, as well, also, of
+absorption and radiation of heat, have as yet furnished no satisfactory
+conclusion as to what really takes place within the cylinder walls.
+There seems to be very little known about dissociation, and somewhat
+vague theories have been advanced to explain the phenomenon. The fact
+is, nevertheless, apparent as shown in the production of water and other
+producer gases by the use of steam in contact with highly incandescent
+fuel. It is known that a maximum explosive mixture of pure gases, as
+hydrogen and oxygen or carbonic oxide and oxygen, suffers a contraction
+of one-third their volume by combustion to their compounds, steam or
+carbonic acid. In the explosive mixtures in the cylinder of a motor,
+however, the combining elements form so small a proportion of the
+contents of the cylinder that the shrinkage of their volume amounts to
+no more than 3 per cent. of the cylinder volume. This by no means
+accounts for the great heat and pressure differences between the
+theoretical and actual effects.
+
+
+CONVERSION OF HEAT TO POWER
+
+The utilization of heat in any heat-engine has long been a theme of
+inquiry and experiment with scientists and engineers, for the purpose of
+obtaining the best practical conditions and construction of heat-engines
+that would represent the highest efficiency or the nearest approach to
+the theoretical value of heat, as measured by empirical laws that have
+been derived from experimental researches relating to its ultimate
+volume. It is well known that the steam-engine returns only from 12 to
+18 per cent. of the power due to the heat generated by the fuel, about
+25 per cent. of the total heat being lost in the chimney, the only use
+of which is to create a draught for the fire; the balance, some 60 per
+cent., is lost in the exhaust and by radiation. The problem of utmost
+utilization of force in steam has nearly reached its limit.
+
+The internal-combustion system of creating power is comparatively new in
+practice, and is but just settling into definite shape by repeated
+trials and modification of details, so as to give somewhat reliable data
+as to what may be expected from the rival of the steam-engine as a prime
+mover. For small powers, the gas, gasoline, and petroleum-oil engines
+are forging ahead at a rapid rate, filling the thousand wants of
+manufacture and business for a power that does not require expensive
+care, that is perfectly safe at all times, that can be used in any place
+in the wide world to which its concentrated fuel can be conveyed, and
+that has eliminated the constant handling of crude fuel and water.
+
+
+REQUISITES FOR BEST POWER EFFECT
+
+The utilization of heat in a gas-engine is mainly due to the manner in
+which the products entering into combustion are distributed in relation
+to the movement of the piston. The investigation of the foremost
+exponent of the theory of the explosive motor was prophetic in
+consideration of the later realization of the best conditions under
+which these motors can be made to meet the requirements of economy and
+practicability. As early as 1862, Beau de Rocha announced, in regard to
+the coming power, that four requisites were the basis of operation for
+economy and best effect. 1. The greatest possible cylinder volume with
+the least possible cooling surface. 2. The greatest possible rapidity of
+expansion. Hence, _high speed_. 3. The greatest possible expansion.
+_Long stroke._ 4. The greatest possible pressure at the commencement of
+expansion. _High compression._
+
+
+
+
+CHAPTER III
+
+ Efficiency of Internal Combustion Engines--Various Measures of
+ Efficiency--Temperatures and Pressures--Factors Governing
+ Economy--Losses in Wall Cooling--Value of Indicator Cards--
+ Compression in Explosive Motors--Factors Limiting Compression--
+ Causes of Heat Losses and Inefficiency--Heat Losses to Cooling
+ Water.
+
+
+EFFICIENCY OF INTERNAL COMBUSTION ENGINES
+
+Efficiencies are worked out through intricate formulas for a variety of
+theoretical and unknown conditions of combustion in the cylinder: ratios
+of clearance and cylinder volume, and the uncertain condition of the
+products of combustion left from the last impulse and the wall
+temperature. But they are of but little value, except as a mathematical
+inquiry as to possibilities. The real commercial efficiency of a gas or
+gasoline-engine depends upon the volume of gas or liquid at some
+assigned cost, required per actual brake horse-power per hour, in which
+an indicator card should show that the mechanical action of the valve
+gear and ignition was as perfect as practicable, and that the ratio of
+clearance, space, and cylinder volume gave a satisfactory terminal
+pressure and compression: _i.e._, the difference between the power
+figured from the indicator card and the brake power being the friction
+loss of the engine.
+
+In four-cycle motors of the compression type, the efficiencies are
+greatly advanced by compression, producing a more complete infusion of
+the mixture of gas or vapor and air, quicker firing, and far greater
+pressure than is possible with the two-cycle type previously described.
+In the practical operation of the gas-engine during the past twenty
+years, the gas-consumption efficiencies per indicated horse-power have
+gradually risen from 17 per cent. to a maximum of 40 per cent. of the
+theoretical heat, and this has been done chiefly through a decreased
+combustion chamber and increased compression--the compression having
+gradually increased in practice from 30 lbs. per square inch to above
+100; but there seems to be a limit to compression, as the efficiency
+ratio decreases with greater increase in compression. It has been shown
+that an ideal efficiency of 33 per cent. for 38 lbs., compression will
+increase to 40 per cent. for 66 lbs., and 43 per cent. for 88 lbs.
+compression. On the other hand, greater compression means greater
+explosive pressure and greater strain on the engine structure, which
+will probably retain in future practice the compression between the
+limits of 40 and 90 lbs. except in super-compression engines intended
+for high altitude work where compression pressures as high as 125 pounds
+have been used.
+
+In experiments made by Dugald Clerk, in England, with a combustion
+chamber equal to 0.6 of the space swept by the piston, with a
+compression of 38 lbs., the consumption of gas was 24 cubic feet per
+indicated horse-power per hour. With 0.4 compression space and 61 lbs.
+compression, the consumption of gas was 20 cubic feet per indicated
+horse-power per hour; and with 0.34 compression space and 87 lbs.
+compression, the consumption of gas fell to 14.8 cubic feet per
+indicated horse-power per hour--the actual efficiencies being
+respectively 17, 21, and 25 per cent. This was with a Crossley
+four-cycle engine.
+
+
+VARIOUS MEASURES OF EFFICIENCY
+
+The efficiencies in regard to power in a heat-engine may be divided
+into four kinds, as follows: I. The first is known as the _maximum
+theoretical efficiency_ of a perfect engine (represented by the
+lines in the indicator diagram). It is expressed by the formula
+(T_{1} - T_{0})/T_{1} and shows the work of a perfect cycle in an engine
+working between the received temperature + absolute temperature (T_{1})
+and the initial atmospheric temperature + absolute temperature (T_{0}).
+II. The second is the _actual heat efficiency_, or the ratio of the heat
+turned into work to the total heat received by the engine. It expresses
+the _indicated horse-power_. III. The third is the ratio between the
+second or _actual heat efficiency_ and the first or _maximum theoretical
+efficiency_ of a perfect cycle. It represents the greatest possible
+utilization of the power of heat in an internal-combustion engine. IV.
+The fourth is the _mechanical efficiency_. This is the ratio between the
+actual horse-power delivered by the engine through a dynamometer or
+measured by a brake (brake horse-power), and the indicated horse-power.
+The difference between the two is the power lost by engine friction. In
+regard to the general heat efficiency of the materials of power in
+explosive engines, we find that with good illuminating gas the practical
+efficiency varies from 25 to 40 per cent.; kerosene-motors, 20 to 30;
+gasoline-motors, 20 to 32; acetylene, 25 to 35; alcohol, 20 to 30 per
+cent. of their heat value. The great variation is no doubt due to
+imperfect mixtures and variable conditions of the old and new charge in
+the cylinder; uncertainty as to leakage and the perfection of
+combustion. In the Diesel motors operating under high pressure, up to
+nearly 500 pounds, an efficiency of 36 per cent. is claimed.
+
+[Illustration: Fig. 12.--Graphic Diagram Showing Approximate Utilization
+of Fuel Burned in Internal-Combustion Engine.]
+
+The graphic diagram at Fig. 12 is of special value as it shows clearly
+how the heat produced by charge combustion is expended in an engine of
+average design.
+
+On general principles the greater difference between the heat of
+combustion and the heat at exhaust is the relative measure of the heat
+turned into work, which represents the degree of efficiency without loss
+during expansion. The mathematical formulas appertaining to the
+computation of the element of heat and its work in an explosive engine
+are in a large measure dependent upon assumed values, as the conditions
+of the heat of combustion are made uncertain by the mixing of the fresh
+charge with the products of a previous combustion, and by absorption,
+radiation, and leakage. The computation of the temperature from the
+observed pressure may be made as before explained, but for
+compression-engines the needed starting-points for computation are very
+uncertain, and can only be approximated from the exact measure and value
+of the elements of combustion in a cylinder charge.
+
+
+TEMPERATURES AND PRESSURES
+
+Owing to the decrease from atmospheric pressure in the indrawing charge
+of the cylinder, caused by valve and frictional obstruction, the
+compression seldom starts above 13 lbs. absolute, especially in
+high-speed engines. Col. 3 in the following table represents the
+approximate absolute compression pressure for the clearance percentage
+and ratio in Cols. 1 and 2, while Col. 4 indicates the gauge pressure
+from the atmospheric line. The temperatures in Col. 5 are due to the
+compression in Col. 3 from an assumed temperature of 560 deg. F. in the
+mixture of the fresh charge of 6 air to 1 gas with the products of
+combustion left in the clearance chamber from the exhaust stroke of a
+medium-speed motor. This temperature is subject to considerable
+variation from the difference in the heat-unit power of the gases and
+vapors used for explosive power, as also of the cylinder-cooling effect.
+In Col. 6 is given the approximate temperatures of explosion for a
+mixture of air 6 to gas 1 of 660 heat units per cubic foot, for the
+relative values of the clearance ratio in Col. 2 at constant volume.
+
+TABLE III.--GAS-ENGINE CLEARANCE RATIOS, APPROXIMATE COMPRESSION,
+TEMPERATURES OF EXPLOSION AND EXPLOSIVE PRESSURES WITH A MIXTURE OF GAS
+OF 660 HEAT UNITS PER CUBIC FOOT AND MIXTURE OF GAS 1 TO 6 OF AIR.
+
+ [A] Clearance Per Cent. of Piston Volume.
+ [B] Ratio (_V_/_V_{c}_) = (_P_ + _C_ Vol.)/Clearance
+ [C] Approximate Compression from 13 Pounds Absolute.
+ [D] Approximate Gauge Pressure.
+ [E] Absolute Temperature of Compression from 560 Deg. Fahrenheit in
+ Cylinder.
+ [F] Absolute Temperature of Explosion. Gas, 1 part; Air, 6 parts.
+ [G] Approximate Explosion Pressure Absolute.
+ [H] Approximate Gauge Pressure.
+ [I] Approximate Temperature of Explosion, Fahrenheit.
+
+ =====+======+======+=====+======+======+=====+=====+=====
+ [A] | [B] | [C] | [D] | [E] | [F] | [G] | [H] | [I]
+ -----+------+------+-----+------+------+-----+-----+-----
+ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
+ -----+------+------+-----+------+------+-----+-----+-----
+ | | Lbs. | | Deg. | Deg. |Lbs. |Lbs. | Deg.
+ .50 | 3. | 57. | 42. | 822. | 2488 | 169 | 144 | 2027
+ .444 | 3.25 | 65. | 50. | 846. | 2568 | 197 | 182 | 2107
+ .40 | 3.50 | 70. | 55. | 868. | 2638 | 212 | 197 | 2177
+ .363 | 3.75 | 77. | 62. | 889. | 2701 | 234 | 219 | 2240
+ .333 | 4. | 84. | 69. | 910. | 2751 | 254 | 239 | 2290
+ .285 | 4.50 | 102. | 88. | 955. | 2842 | 303 | 288 | 2381
+ .25 | 5. | 114. | 99. | 983. | 2901 | 336 | 321 | 2440
+ -----+------+------+-----+------+------+-----+-----+-----
+
+
+FACTORS GOVERNING ECONOMY
+
+In view of the experiments in this direction, it clearly shows that in
+practical work, to obtain the greatest economy per effective brake
+horse-power, it is necessary: 1st. To transform the heat into work with
+the greatest rapidity mechanically allowable. This means high piston
+speed. 2d. To have high initial compression. 3d. To reduce the duration
+of contact between the hot gases and the cylinder walls to the smallest
+amount possible; which means short stroke and quick speed, with a
+spherical cylinder head. 4th. To adjust the temperature of the jacket
+water to obtain the most economical output of actual power. This means
+water-tanks or water-coils, with air-cooling surfaces suitable and
+adjustable to the most economical requirement of the engine, which by
+late trials requires the jacket water to be discharged at about 200 deg.
+F. 5th. To reduce the wall surface of the clearance space or combustion
+chamber to the smallest possible area, in proportion to its required
+volume. This lessens the loss of the heat of combustion by exposure to a
+large surface, and allows of a higher mean wall temperature to
+facilitate the heat of compression.
+
+
+LOSSES IN WALL COOLING
+
+In an experimental investigation of the efficiency of a gas-engine under
+variable piston speeds made in France, it was found that the useful
+effect increases with the velocity of the piston--that is, with the rate
+of expansion of the burning gases with mixtures of uniform volumes: so
+that the variations of time of complete combustion at constant pressure,
+and the variations due to speed, in a way compensate in their
+efficiencies. The dilute mixture, being slow burning, will have its time
+and pressure quickened by increasing the speed.
+
+Careful trials give unmistakable evidence that the useful effect
+increases with the velocity of the piston--that is, with the rate of
+expansion of the burning gases. The time necessary for the explosion to
+become complete and to attain its maximum pressure depends not only on
+the composition of the mixture, but also upon the rate of expansion.
+This has been verified in experiments with a high-speed motor, at speeds
+from 500 to 2,000 revolutions per minute, or piston speeds of from 16 to
+64 feet per second. The increased speed of combustion due to increased
+piston speed is a matter of great importance to builders of gas-engines,
+as well as to the users, as indicating the mechanical direction of
+improvements to lessen the wearing strain due to high speed and to
+lighten the vibrating parts with increased strength, in order that the
+balancing of high-speed engines may be accomplished with the least
+weight.
+
+From many experiments made in Europe and in the United States, it has
+been conclusively proved that excessive cylinder cooling by the
+water-jacket results in a marked loss of efficiency. In a series of
+experiments with a simplex engine in France, it was found that a saving
+of 7 per cent. in gas consumption per brake horse-power was made by
+raising the temperature of the jacket water from 141 deg. to 165 deg. F.
+A still greater saving was made in a trial with an Otto engine by raising
+the temperature of the jacket water from 61 deg. to 140 deg. F.--it being
+9.5 per cent. less gas per brake horse-power.
+
+It has been stated that volumes of similar cylinders increase as the
+cube of their diameters, while the surface of their cold walls varies as
+the square of their diameters; so that for large cylinders the ratio of
+surface to volume is less than for small ones. This points to greater
+economy in the larger engines. The study of many experiments goes to
+prove that combustion takes place gradually in the gas-engine cylinder,
+and that the rate of increase of pressure or rapidity of firing is
+controlled by dilution and compression of the mixture, as well as by the
+rate of expansion or piston speed. The rate of combustion also depends
+on the size and shape of the explosion chamber, and is increased by the
+mechanical agitation of the mixture during combustion, and still more by
+the mode of firing.
+
+
+VALUE OF INDICATOR CARDS
+
+[Illustration: Fig. 13.--Otto Four-Cycle Card.]
+
+To the uninitiated, indicator cards are considerable of a mystery; to
+those capable of reading them they form an index relative to the action
+of any engine. An indicator card, such as shown at Fig. 13, is merely a
+graphical representation of the various pressures existing in the
+cylinder for different positions of the piston. The length is to some
+scale that represents the stroke of the piston. During the intake
+stroke, the pressure falls below the atmospheric line. During
+compression, the curve gradually becomes higher owing to increasing
+pressure as the volume is reduced. After ignition the pressure line
+moves upward almost straight, then as the piston goes down on the
+explosion stroke, the pressure falls gradually to the point of exhaust
+valve, opening when the sudden release of the imprisoned gas causes a
+reduction in pressure to nearly atmospheric. An indicator card, or a
+series of them, will always show by its lines the normal or defective
+condition of the inlet valve and passages; the actual line of
+compression; the firing moment; the pressure of explosion; the velocity
+of combustion; the normal or defective line of expansion, as measured by
+the adiabatic curve, and the normal or defective operation of the
+exhaust valve, exhaust passages, and exhaust pipe. In fact, all the
+cycles of an explosive motor may be made a practical study from a close
+investigation of the lines of an indicator card.
+
+[Illustration: Fig. 14.--Diesel Motor Card.]
+
+A most unique card is that of the Diesel motor (Fig. 14), which involves
+a distinct principle in the design and operation of internal-combustion
+motors, in that instead of taking a mixed charge for instantaneous
+explosion, its charge primarily is of air and its compression to a
+pressure at which a temperature is attained above the igniting point of
+the fuel, then injecting the fuel under a still higher pressure by which
+spontaneous combustion takes place gradually with increasing volume over
+the compression for part of the stroke or until the fuel charge is
+consumed. The motor thus operating between the pressures of 500 and 35
+lbs. per square inch, with a clearance of about 7 per cent., has given
+an efficiency of 36 per cent. of the total heat value of kerosene oil.
+
+
+COMPRESSION IN EXPLOSIVE MOTORS
+
+That the compression in a gas, gasoline, or oil-engine has a direct
+relation to the power obtained, has been long known to experienced
+builders, having been suggested by M. Beau de Rocha, in 1862, and
+afterward brought into practical use in the four-cycle or Otto type
+about 1880. The degree of compression has had a growth from zero, in the
+early engines, to the highest available due to the varying ignition
+temperatures of the different gases and vapors used for explosive fuel,
+in order to avoid premature explosion from the heat of compression. Much
+of the increased power for equal-cylinder capacity is due to compression
+of the charge from the fact that the most powerful explosion of gases,
+or of any form of explosive material, takes place when the particles are
+in the closest contact or cohesion with one another, less energy in this
+form being consumed by the ingredients themselves to bring about their
+chemical combination, and consequently more energy is given out in
+useful or available work. This is best shown by the ignition of
+gunpowder, which, when ignited in the open air, burns rapidly, but
+without explosion, an explosion only taking place if the powder be
+confined or compressed into a small space.
+
+[Illustration: Fig. 15.--Diagram of Heat in the Gas Engine Cylinder.]
+
+In a gas or gasoline-motor with a small clearance or compression
+space--with high compression--the surface with which the burning
+gases come into contact is much smaller in comparison with the
+compression space in a low-compression motor. Another advantage of a
+high-compression motor is that on account of the smaller clearance
+of combustion space less cooling water is required than with a
+low-compression motor, as the temperature, and consequently the
+pressure, falls more rapidly. The loss of heat through the water-jacket
+is thus less in the case of a high-compression than in that of a
+low-compression motor. In the non-compression type of motor the best
+results were obtained with a charge of 16 to 18 parts of gas and 100
+parts of air, while in the compression type the best results are
+obtained with an explosive mixture of 7 to 10 parts of gas and 100 parts
+of air, thus showing that by the utilization of compression a weaker
+charge with a greater thermal efficiency is permissible.
+
+It has been found that the explosive pressure resulting from the
+ignition of the charge of gas or gasoline-vapor and air in the
+gas-engine cylinder is about 4-1/2 times the pressure prior to ignition.
+The difficulty about getting high compression is that if the pressure is
+too high the charge is likely to ignite prematurely, as compression
+always results in increased temperature. The cylinder may become too
+hot, a deposit of carbon, a projecting electrode or plug body in the
+cylinder may become incandescent and ignite the charge which has been
+excessively heated by the high compression and mixture of the hot gases
+of the previous explosion.
+
+
+FACTORS LIMITING COMPRESSION
+
+With gasoline-vapor and air the compression should not be raised above
+about 90 to 95 pounds to the square inch, many manufacturers not going
+above 65 or 70 pounds. For natural gas the compression pressure may
+easily be raised to from 85 to 100 pounds per square inch. For gases of
+low calorific value, such as blast-furnace or producer-gas, the
+compression may be increased to from 140 to 190 pounds. In fact the
+ability to raise the compression to a high point with these gases is one
+of the principal reasons for their successful adoption for gas-engine
+use. In kerosene injection engines the compression of 250 pounds per
+square inch has been used with marked economy. Many troubles in regard
+to loss of power and increase of fuel have occurred and will no doubt
+continue, owing to the wear of valves, piston, and cylinder, which
+produces a loss in compression and explosive pressure and a waste of
+fuel by leakage. Faulty adjustment of valve movement is also a cause of
+loss of power; which may be from tardy closing of the inlet-valve or a
+too early opening of the exhaust-valve.
+
+The explosive pressure varies to a considerable amount in proportion to
+the compression pressure by the difference in fuel value and the
+proportions of air mixtures, so that for good illuminating gas the
+explosive pressure may be from 2.5 to 4 times the compression pressure.
+For natural gas 3 to 4.5, for gasoline 3 to 5, for producer-gas 2 to 3,
+and for kerosene by injection 3 to 6.
+
+The compression temperatures, although well known and easily computed
+from a known normal temperature of the explosive mixture, are subject to
+the effect of the uncertain temperature of the gases of the previous
+explosion remaining in the cylinder, the temperature of its walls, and
+the relative volume of the charge, whether full or scant; which are
+terms too variable to make any computations reliable or available.
+
+For the theoretical compression temperatures from a known normal
+temperature, we append a table of the rise in temperature for the
+compression pressures in the following table:
+
+TABLE IV.--COMPRESSION TEMPERATURES FROM A NORMAL TEMPERATURE OF 60
+DEGREES FAHRENHEIT.
+
+ ===============================+==============================
+ 100 lbs. gauge 484 deg. | 60 lbs. gauge 373 deg.
+ 90 lbs. gauge 459 deg. | 50 lbs. gauge 339 deg.
+ 80 lbs. gauge 433 deg. | 40 lbs. gauge 301 deg.
+ 70 lbs. gauge 404 deg. | 30 lbs. gauge 258 deg.
+ -------------------------------+------------------------------
+
+
+CHART FOR DETERMINING COMPRESSION PRESSURES
+
+A very useful chart (Fig. 16) for determining compression pressures in
+gasoline-engine cylinders for various ratios of compression space to
+total cylinder volume is given by P. S. Tice, and described in the
+Chilton Automobile Directory by the originator as follows:
+
+[Illustration: Fig. 16.--Chart Showing Relation Between Compression
+Volume and Pressure.]
+
+It is many times desirable to have at hand a convenient means for at
+once determining with accuracy what the compression pressure will be in
+a gasoline-engine cylinder, the relationship between the volume of the
+compression space and the total cylinder volume or that swept by the
+piston being known. The curve at Fig. 16 is offered as such a means. It
+is based on empirical data gathered from upward of two dozen modern
+automobile engines and represents what may be taken to be the results as
+found in practice. It is usual for the designer to find compression
+pressure values, knowing the volumes from the equation
+
+ P_{2} = P_{1} (V_{1}/V_{2})^{1.4} 1
+
+which is for adiabatic compression of air. Equation (1) is right enough
+in general form but gives results which are entirely too high, as
+almost all designers know from experience. The trouble lies in the
+interchange of heat between the compressed gases and the cylinder walls,
+in the diminution of the exponent (1.4 in the above) due to the lesser
+ratio of specific heat of gasoline vapor and in the transfer of heat
+from the gases which are being compressed to whatever fuel may enter the
+cylinder in an unvaporized condition. Also, there is always some piston
+leakage, and, if the form of the equation (1) is to be retained, this
+also tends to lower the value of the exponent. From experience with many
+engines, it appears that compression reaches its highest value in the
+cylinder for but a short range of motor speeds, usually during the
+mid-range. Also, it appears that, at those speeds at which compression
+shows its highest values, the initial pressure at the start of the
+compression stroke is from .5 to .9 lb. below atmospheric. Taking this
+latter loss value, which shows more often than those of lesser value,
+the compression is seen to start from an initial pressure of 13.9 lbs.
+per sq. in. absolute.
+
+Also, experiment shows that if the exponent be given the value 1.26,
+instead of 1.4, the equation will embrace all heat losses in the
+compressed gas, and compensate for the changed ratio of specific heats
+for the mixture and also for all piston leakage, in the average engine
+with rings in good condition and tight. In the light of the foregoing,
+and in view of results obtained from its use, the above curve is
+offered--values of P_{2} being found from the equation
+
+ P_{2} = 13.8 (V_{1}/V_{2})^{1.26}
+
+In using this curve it must be remembered that pressures are absolute.
+Thus: suppose it is desired to know the volumetric relationships of the
+cylinder for a compression pressure of 75 lbs. gauge. Add atmospheric
+pressure to the desired gauge pressure 14.7 + 75 = 89.7 lbs. absolute.
+Locate this pressure on the scale of ordinates and follow horizontally
+across to the curve and then vertically downward to the scale of
+abscissas, where the ratio of the combustion chamber volume to the total
+cylinder volume is given, which latter is equal to the sum of the
+combustion chamber volume and that of the piston sweep. In the above
+case it is found that the combustion space for a compression pressure of
+75 lbs. gauge will be .225 of the total cylinder volume, or .225 / .775
+= .2905 of the piston sweep volume. Conversely, knowing the volumetric
+ratios, compression pressure can be read directly by proceeding from the
+scale of abscissas vertically to the curve and thence horizontally to
+the scale of ordinates.
+
+
+CAUSES OF HEAT LOSS AND INEFFICIENCY IN EXPLOSIVE MOTORS
+
+The difference realized in the practical operation of an internal
+combustion heat engine from the computed effect derived from the values
+of the explosive elements is probably the most serious difficulty that
+engineers have encountered in their endeavors to arrive at a rational
+conclusion as to where the losses were located, and the ways and means
+of design that would eliminate the causes of loss and raise the
+efficiency step by step to a reasonable percentage of the total
+efficiency of a perfect cycle.
+
+An authority on the relative condition of the chemical elements under
+combustion in closed cylinders attributes the variation of temperature
+shown in the fall of the expansion curve, and the suppression or
+retarded evolution of heat, entirely to the cooling action of the
+cylinder walls, and to this nearly all the phenomena hitherto obscure in
+the cylinder of a gas-engine. Others attribute the great difference
+between the theoretical temperature of combustion and the actual
+temperature realized in the practical operation of the gas-engine, a
+loss of more than one-half of the total heat energy of the combustibles,
+partly to the dissociation of the elements of combustion at extremely
+high temperatures and their reassociation by expansion in the cylinder,
+to account for the supposed continued combustion and extra adiabatic
+curve of the expansion line on the indicator card.
+
+[Illustration: Fig. 17.--The Thompson Indicator, an Instrument for
+Determining Compressions and Explosion Pressure Values and Recording
+Them on Chart.]
+
+The loss of heat to the walls of the cylinder, piston, and clearance
+space, as regards the proportion of wall surface to the volume, has
+gradually brought this point to its smallest ratio in the concave
+piston-head and globular cylinder-head, with the smallest possible space
+in the inlet and exhaust passage. The wall surface of a cylindrical
+clearance space or combustion chamber of one-half its unit diameter in
+length is equal to 3.1416 square units, its volume but 0.3927 of a cubic
+unit; while the same wall surface in a spherical form has a volume of
+0.5236 of a cubic unit. It will be readily seen that the volume is
+increased 33-1/3 per cent. in a spherical over a cylindrical form for
+equal wall surfaces at the moment of explosion, when it is desirable
+that the greatest amount of heat is generated, and carrying with it the
+greatest possible pressure from which the expansion takes place by the
+movement of the piston.
+
+[Illustration: Fig. 18.--Spherical Combustion Chamber.]
+
+[Illustration: Fig. 19.--Enlarged Combustion Chamber.]
+
+The spherical form cannot continue during the stroke for mechanical
+reasons; therefore some proportion of piston stroke of cylinder volume
+must be found to correspond with a spherical form of the combustion
+chamber to produce the least loss of heat through the walls during the
+combustion and expansion part of the stroke. This idea is illustrated in
+Figs. 18 and 19, showing how the relative volumes of cylinder stroke and
+combustion chamber may be varied to suit the requirements due to the
+quality of the elements of combustion.
+
+Although the concave piston-head shows economy in regard to the relation
+of the clearance volume to the wall area at the moment of explosive
+combustion, it may be clearly seen that its concavity increases its
+surface area and its capacity for absorbing heat, for which there is no
+provision for cooling the piston, save its contact with the walls of the
+cylinder and the slight air cooling of its back by its reciprocal
+motion. For this reason the concave piston-head has not been generally
+adopted and the concave cylinder-head, as shown in Fig. 19, with a
+flat piston-head is the latest and best practice in airplane engine
+construction.
+
+[Illustration: Fig. 20.--Mercedes Aviation Engine Cylinder Section
+Showing Approximately Spherical Combustion Chamber and Concave Piston
+Top.]
+
+The practical application of the principle just outlined to one of the
+most efficient airplane motors ever designed, the Mercedes, is clearly
+outlined at Fig. 20.
+
+
+HEAT LOSSES TO COOLING WATER
+
+The mean temperature of the wall surface of the combustion chamber and
+cylinder, as indicated by the temperatures of the circulating water, has
+been found to be an important item in the economy of the gas-engine.
+Dugald Clerk, in England, a high authority in practical work with the
+gas-engine, found that 10 per cent. of the gas for a stated amount of
+power was saved by using water at a temperature in which the ejected
+water from the cylinder-jacket was near the boiling-point, and ventures
+the opinion that a still higher temperature for the circulating water
+may be used as a source of economy. This could be made practical in the
+case of aviation engines by adjusting the air-cooling surface of the
+radiator so as to maintain the inlet water at just below the boiling
+point, and by the rapid circulation induced by the pump pressure, to
+return the water from the cylinder-jacket a few degrees above the
+boiling point. The thermal displacement systems of cooling employed in
+automobiles are working under more favorable temperature conditions than
+those engines in which cooling is more energetic.
+
+For a given amount of heat taken from the cylinder by the largest volume
+of circulating water, the difference in temperature between inlet and
+outlet of the water-jacket should be the least possible, and this
+condition of the water circulation gives a more even temperature to all
+parts of the cylinder; while, on the contrary, a cold-water supply, say
+at 60 deg. F., so slow as to allow the ejected water to flow off at a
+temperature near the boiling-point, must make a great difference in
+temperature between the bottom and top of the cylinder, with a loss in
+economy in gas and other fuels, as well as in water, if it is obtained
+by measurement.
+
+From the foregoing considerations of losses and inefficiencies, we find
+that the practice in motor design and construction has not yet reached
+the desired perfection in its cycular operation. Step by step
+improvements have been made with many changes in design though many have
+been without merit as an improvement, farther than to gratify the
+longings of designers for something different from the other thing, and
+to establish a special construction of their own. These efforts may in
+time produce a motor of normal or standard design for each kind of fuel
+that will give the highest possible efficiency for all conditions of
+service.
+
+
+
+
+CHAPTER IV
+
+ Engine Parts and Functions--Why Multiple Cylinder Engines Are
+ Best--Describing Sequence of Operations--Simple Engines--Four
+ and Six Cylinder Vertical Tandem Engines--Eight and Twelve
+ Cylinder V Engines--Radial Cylinder Arrangement--Rotary Cylinder
+ Forms.
+
+
+ENGINE PARTS AND FUNCTIONS
+
+The principal elements of a gas engine are not difficult to understand
+and their functions are easily defined. In place of the barrel of the
+gun one has a smoothly machined cylinder in which a small cylindrical or
+barrel-shaped element fitting the bore closely may be likened to a
+bullet or cannon ball. It differs in this important respect, however, as
+while the shot is discharged from the mouth of the cannon the piston
+member sliding inside of the main cylinder cannot leave it, as its
+movements back and forth from the open to the closed end and back again
+are limited by simple mechanical connection or linkage which comprises
+crank and connection rod. It is by this means that the reciprocating
+movement of the piston is transformed into a rotary motion of the
+crank-shaft.
+
+The fly-wheel is a heavy member attached to the crank-shaft of an
+automobile engine which has energy stored in its rim as the member
+revolves, and the momentum of this revolving mass tends to equalize the
+intermittent pushes on the piston head produced by the explosion of the
+gas in the cylinder. In aviation engines, the weight of the propeller or
+that of rotating cylinders themselves performs the duty of a fly-wheel,
+so no separate member is needed. If some explosive is placed in the
+chamber formed by the piston and closed end of the cylinder and
+exploded, the piston would be the only part that would yield to the
+pressure which would produce a downward movement. As this is forced down
+the crank-shaft is turned by the connecting rod, and as this part is
+hinged at both ends it is free to oscillate as the crank turns, and thus
+the piston may slide back and forth while the crank-shaft is rotating or
+describing a curvilinear path.
+
+[Illustration: Fig. 21.--Side Sectional View of Typical Airplane Engine,
+Showing Parts and Their Relation to Each Other. This Engine is an
+Aeromarine Design and Utilizes a Distinctive Concentric Valve
+Construction.]
+
+In addition to the simple elements described it is evident that a
+gasoline engine must have other parts. The most important of these are
+the valves, of which there are generally two to each cylinder. One
+closes the passage connecting to the gas supply and opens during one
+stroke of the piston in order to let the explosive gas into the
+combustion chamber. The other member, or exhaust valve, serves as a
+cover for the opening through which the burned gases can leave the
+cylinder after their work is done. The spark plug is a simple device
+which may be compared to the fuse or percussion cap of the cannon. It
+permits one to produce an electric spark in the cylinder when the piston
+is at the best point to utilize the pressure which obtains when the
+compressed gas is fired. The valves are open one at a time, the inlet
+valve being lifted from its seat while the cylinder is filling and the
+exhaust valve is opened when the cylinder is being cleared. They are
+normally kept seated by means of compression springs. In the simple
+motor shown at Fig. 5, the exhaust valve is operated by means of a
+pivoted bell crank rocked by a cam which turns at half the speed of the
+crank-shaft. The inlet valve operates automatically, as will be
+explained in proper sequence.
+
+In order to obtain a perfectly tight combustion chamber, both intake and
+exhaust valves are closed before the gas is ignited, because all of the
+pressure produced by the exploding gas is to be directed against the top
+of the movable piston. When the piston reaches the bottom of its power
+stroke, the exhaust valve is lifted by means of the bell crank which is
+rocked because of the point or lift on the cam. The cam-shaft is driven
+by positive gearing and revolves at half the engine speed. The exhaust
+valve remains open during the whole of the return stroke of the piston,
+and as this member moves toward the closed end of the cylinder it
+forces out burned gases ahead of it, through the passage controlled by
+the exhaust valve. The cam-shaft is revolved at half the engine speed
+because the exhaust valve is raised from its seat during only one stroke
+out of four, or only once every two revolutions. Obviously, if the cam
+was turned at the same speed as the crank-shaft it would remain open
+once every revolution, whereas the burned gases are expelled from the
+individual cylinders only once in two turns of the crank-shaft.
+
+
+WHY MULTIPLE CYLINDER FORMS ARE BEST
+
+Owing to the vibration which obtains from the heavy explosion in the
+large single-cylinder engines used for stationary power other forms were
+evolved in which the cylinder was smaller and power obtained by running
+the engine faster, but these are suitable only for very low powers.
+
+When a single-cylinder engine is employed a very heavy fly-wheel is
+needed to carry the moving parts through idle strokes necessary to
+obtain a power impulse. For this reason automobile and aircraft
+designers must use more than one cylinder, and the tendency is to
+produce power by frequently occurring light impulses rather than
+by a smaller number of explosions having greater force. When a
+single-cylinder motor is employed the construction is heavier than is
+needed with a multiple-cylinder form. Using two or more cylinders
+conduces to steady power generation and a lessening of vibration. Most
+modern motor cars employ four-cylinder engines because a power impulse
+may be secured twice every revolution of the crank-shaft, or a total of
+four power strokes during two revolutions. The parts are so arranged
+that while the charge of gas in one cylinder is exploding, those which
+come next in firing order are compressing, discharging the inert gases
+and drawing in a fresh charge respectively. When the power stroke is
+completed in one cylinder, the piston in that member in which a charge
+of gas has just been compressed has reached the top of its stroke and
+when the gas is exploded the piston is reciprocated and keeps the
+crank-shaft turning. When a multiple-cylinder engine is used the
+fly-wheel can be made much lighter than that of the simpler form and
+eliminated altogether in some designs. In fact, many modern
+multiple-cylinder engines developing 300 horse-power weigh less than the
+early single- and double-cylinder forms which developed but one-tenth or
+one-twentieth that amount of energy.
+
+
+DESCRIBING SEQUENCE OF OPERATIONS
+
+Referring to Fig. 22, A, the sequence of operation in a single-cylinder
+motor can be easily understood. Assuming that the crank-shaft is turning
+in the direction of the arrow, it will be seen that the intake stroke
+comes first, then the compression, which is followed by the power
+impulse, and lastly the exhaust stroke. If two cylinders are used, it is
+possible to balance the explosions in such a way that one will occur
+each revolution. This is true with either one of two forms of four-cycle
+motors. At B, a two-cylinder vertical engine using a crank-shaft in
+which the crank-pins are on the same plane is shown. The two pistons
+move up and down simultaneously. Referring to the diagram describing the
+strokes, and assuming that the outer circle represents the cycle of
+operations in one cylinder while the inner circle represents the
+sequence of events in the other cylinder, while cylinder No. 1 is taking
+in a fresh charge of gas, cylinder No. 2 is exploding. When cylinder No.
+1 is compressing, cylinder No. 2 is exhausting. During the time that the
+charge in cylinder No. 1 is exploded, cylinder No. 2 is being filled
+with fresh gas. While the exhaust gases are being discharged from
+cylinder No. 1, cylinder No. 2 is compressing the gas previously taken.
+
+[Illustration: Fig. 22.--Diagrams Illustrating Sequence of Cycles in
+One- and Two-Cylinder Engines Showing More Uniform Turning Effort on
+Crank-Shaft with Two-Cylinder Motors.]
+
+The same condition obtains when the crank-pins are arranged at one
+hundred and eighty degrees and the cylinders are opposed, as shown at C.
+The reason that the two-cylinder opposed motor is more popular than
+that having two vertical cylinders is that it is difficult to balance
+the construction shown at B, so that the vibration will not be
+excessive. The two-cylinder opposed motor has much less vibration than
+the other form, and as the explosions occur evenly and the motor is a
+simple one to construct, it has been very popular in the past on light
+cars and has received limited application on some early, light
+airplanes.
+
+To demonstrate very clearly the advantages of multiple-cylinder engines
+the diagrams at Fig. 23 have been prepared. At A, a three-cylinder
+motor, having crank-pins at one hundred and twenty degrees, which means
+that they are spaced at thirds of the circle, we have a form of
+construction that gives a more even turning than that possible with a
+two-cylinder engine. Instead of one explosion per revolution of the
+crank-shaft, one will obtain three explosions in two revolutions. The
+manner in which the explosion strokes occur and the manner they overlap
+strokes in the other cylinder is shown at A. Assuming that the cylinders
+fire in the following order, first No. 1, then No. 2, and last No. 3, we
+will see that while cylinder No. 1, represented by the outer circle, is
+on the power stroke, cylinder No. 3 has completed the last two-thirds of
+its exhaust stroke and has started on its intake stroke. Cylinder No. 2,
+represented by the middle circle, during this same period has completed
+its intake stroke and two-thirds of its compression stroke. A study of
+the diagram will show that there is an appreciable lapse of time between
+each explosion.
+
+Three-cylinder engines are not used on aircraft at the present time,
+though Bleriot's flight across the British Channel was made with a
+three-cylinder Anzani motor. It was not a conventional form, however.
+The three-cylinder engine is practically obsolete at this time for any
+purpose except "penguins" or school machines that are incapable of
+flight and which are used in some French training schools for aviators.
+
+[Illustration: Fig. 23.--Diagrams Demonstrating Clearly Advantages which
+Obtain when Multiple-Cylinder Motors are Used as Power Plants.]
+
+
+FOUR- AND SIX-CYLINDER ENGINES
+
+In the four-cylinder engine operation which is shown at Fig. 23, B, it
+will be seen that the power strokes follow each other without loss of
+time, and one cylinder begins to fire and the piston moves down just as
+soon as the member ahead of it has completed its power stroke. In a
+four-cylinder motor, the crank-pins are placed at one hundred and eighty
+degrees, or on the halves of the crank circle. The crank-pins for
+cylinders No. 1 and No. 4 are on the same plane, while those for
+cylinders No. 2 and No. 3 also move in unison. The diagram describing
+sequence of operations in each cylinder is based on a firing order of
+one, two, four, three. The outer circle, as in previous instances,
+represents the cycle of operations in cylinder one. The next one toward
+the center, cylinder No. 2, the third circle represents the sequence of
+events in cylinder No. 3, while the inner circle outlines the strokes in
+cylinder four. The various cylinders are working as follows:
+
+ 1. 2. 3. 4.
+
+ Explosion Compression Exhaust Intake
+ Exhaust Explosion Intake Compression
+ Intake Exhaust Compression Explosion
+ Compression Intake Explosion Exhaust
+
+It will be obvious that regardless of the method of construction, or the
+number of cylinders employed, exactly the same number of parts must be
+used in each cylinder assembly and one can conveniently compare any
+multiple-cylinder power plant as a series of single-cylinder engines
+joined one behind the other and so coupled that one will deliver power
+and produce useful energy at the crank-shaft where the other leaves off.
+The same fundamental laws governing the action of a single cylinder
+obtain when a number are employed, and the sequence of operation is the
+same in all members, except that the necessary functions take place at
+different times. If, for instance, all the cylinders of a four-cylinder
+motor were fired at the same time, one would obtain the same effect as
+though a one-piston engine was used, which had a piston displacement
+equal to that of the four smaller members. As is the case with a
+single-cylinder engine, the motor would be out of correct mechanical
+balance because all the connecting rods would be placed on crank-pins
+that lie in the same plane. A very large fly-wheel would be necessary to
+carry the piston through the idle strokes, and large balance weights
+would be fitted to the crank-shaft in an effort to compensate for the
+weight of the four pistons, and thus reduce vibratory stresses which
+obtain when parts are not in correct balance.
+
+There would be no advantage gained by using four cylinders in this
+manner, and there would be more loss of heat and more power consumed in
+friction than in a one-piston motor of the same capacity. This is the
+reason that when four cylinders are used the arrangement of crank-pins
+is always as shown at Fig. 23, B--i.e., two pistons are up, while the
+other two are at the bottom of the stroke. With this construction, we
+have seen that it is possible to string out the explosions so that there
+will always be one cylinder applying power to the crank-shaft. The
+explosions are spaced equally. The parts are in correct mechanical
+balance because two pistons are on the upstroke while the other two are
+descending. Care is taken to have one set of moving members weigh
+exactly the same as the other. With a four-cylinder engine one has
+correct balance and continuous application of energy. This insures a
+smoother running motor which has greater efficiency than the simpler
+one-, two-, and three-cylinder forms previously described. Eliminating
+the stresses which would obtain if we had an unbalanced mechanism and
+irregular power application makes for longer life. Obviously a large
+number of relatively light explosions will produce less wear and strain
+than would a lesser number of powerful ones. As the parts can be built
+lighter if the explosions are not heavy, the engine can be operated at
+higher rotative speeds than when large and cumbersome members are
+utilized. Four-cylinder engines intended for aviation work have been
+built according to the designs shown at Fig. 24, but these forms are
+unconventional and seldom if ever used.
+
+[Illustration: Fig. 24.--Showing Three Possible Though Unconventional
+Arrangements of Four-Cylinder Engines.]
+
+The six-cylinder type of motor, the action of which is shown at Fig. 23,
+C, is superior to the four-cylinder, inasmuch as the power strokes
+overlap, and instead of having two explosions each revolution we have
+three explosions. The conventional crank-shaft arrangement in a
+six-cylinder engine is just the same as though one used two
+three-cylinder shafts fastened together, so pistons 1 and 6 are on the
+same plane as are pistons 2 and 5. Pistons 3 and 4 also travel together.
+With the cranks arranged as outlined at Fig. 23, C, the firing order is
+one, five, three, six, two, four. The manner in which the power strokes
+overlap is clearly shown in the diagram. An interesting comparison is
+also made in the diagrams at Fig. 25 and in the upper corner of Fig. 23,
+C.
+
+[Illustration: Fig. 25.--Diagrams Outlining Advantages of Multiple
+Cylinder Motors, and Why They Deliver Power More Evenly Than Single
+Cylinder Types.]
+
+A rectangle is divided into four columns; each of these corresponds to
+one hundred and eighty degrees, or half a revolution. Thus the first
+revolution of the crank-shaft is represented by the first two columns,
+while the second revolution is represented by the last two. Taking the
+portion of the diagram which shows the power impulse in a one-cylinder
+engine, we see that during the first revolution there has been no power
+impulse. During the first half of the second revolution, however, an
+explosion takes place and a power impulse is obtained. The last portion
+of the second revolution is devoted to exhausting the burned gases, so
+that there are three idle strokes and but one power stroke. The effect
+when two cylinders are employed is shown immediately below.
+
+[Illustration: Fig. 26.--Diagrams Showing Duration of Events for a
+Four-Stroke Cycle, Six-Cylinder Engine.]
+
+Here we have one explosion during the first half of the first revolution
+in one cylinder and another during the first half of the second
+revolution in the other cylinder. With a four-cylinder engine there is
+an explosion each half revolution, while in a six-cylinder engine there
+is one and one-half explosions during each half revolution. When six
+cylinders are used there is no lapse of time between power impulses, as
+these overlap and a continuous and smooth-turning movement is imparted
+to the crank shaft. The diagram shown at Fig. 26, prepared by E. P.
+Pulley, can be studied to advantage in securing an idea of the
+coordination of effort that takes place in an engine of the six-cylinder
+type.
+
+
+ACTUAL DURATION OF DIFFERENT STROKES
+
+[Illustration: Fig. 27.--Diagram Showing Actual Duration of Different
+Strokes in Degrees.]
+
+In the diagrams previously presented the writer has assumed, for the
+sake of simplicity, that each stroke takes place during half of one
+revolution of the crank-shaft, which corresponds to a crank-pin travel
+of one hundred and eighty degrees. The actual duration of these strokes
+is somewhat different. For example, the inlet stroke is usually a trifle
+more than a half revolution, and the exhaust is always considerably
+more. The diagram showing the comparative duration of the strokes is
+shown at Fig. 27. The inlet valve opens ten degrees after the piston
+starts to go down and remains open thirty degrees after the piston has
+reached the bottom of its stroke. This means that the suction stroke
+corresponds to a crank-pin travel of two hundred degrees, while the
+compression stroke is measured by a movement of but one hundred and
+fifty degrees. It is common practice to open the exhaust valve before
+the piston reaches the end of the power stroke so that the actual
+duration of the power stroke is about one hundred and forty degrees,
+while the exhaust stroke corresponds to a crank-pin travel of two
+hundred and twenty-five degrees. In this diagram, which represents
+proper time for the valves to open and close, the dimensions in inches
+given are measured on the fly-wheel and apply only to a certain
+automobile motor. If the fly-wheel were smaller ten degrees would take
+up less than the dimensions given, while if the fly-wheel was larger a
+greater space on its circumference would represent the same crank-pin
+travel. Aviation engines are timed by using a timing disc attached to
+the crank-shaft as they are not provided with fly-wheels. Obviously, the
+distance measured in inches will depend upon the diameter of the disc,
+though the number of degrees interval would not change.
+
+[Illustration: Fig. 28.--Another Diagram to Facilitate Understanding
+Sequence of Functions in Six-Cylinder Engine.]
+
+
+EIGHT- AND TWELVE-CYLINDER V ENGINES
+
+Those who have followed the development of the gasoline engine will
+recall the arguments that were made when the six-cylinder motor was
+introduced at a time that the four-cylinder type was considered
+standard. The arrival of the eight-cylinder has created similar futile
+discussion of its practicability as this is so clearly established as to
+be accepted without question. It has been a standard power plant for
+aeroplanes for many years, early exponents having been the Antoinette,
+the Woolsley, the Renault, the E. N. V. in Europe and the Curtiss in the
+United States.
+
+[Illustration: Fig. 29.--Types of Eight-Cylinder Engines Showing the
+Advantage of the V Method of Cylinder Placing.]
+
+The reason the V type shown at Fig. 29, A is favored is that the
+"all-in-line form" which is shown at Fig. 29, B is not practical for
+aircraft because of its length. Compared to the standard four-cylinder
+engine it is nearly twice as long and it required a much stronger and
+longer crank-shaft. It will be evident that it could not be located to
+advantage in the airplane fuselage. These undesirable factors are
+eliminated in the V type eight-cylinder motor, as it consists of two
+blocks of four cylinders each, so arranged that one set or block is at
+an angle of forty-five degrees from the vertical center line of the
+motor, or at an angle of ninety degrees with the other set. This
+arrangement of cylinders produces a motor that is no longer than a
+four-cylinder engine of half the power would be.
+
+[Illustration: Fig. 30.--Curves Showing Torque of Various Engine Types
+Demonstrate Graphically Marked Advantage of the Eight-Cylinder Type.]
+
+Apparently there is considerable misconception as to the advantage of
+the two extra cylinders of the eight as compared with the six-cylinder.
+It should be borne in mind that the multiplication in the number of
+cylinders noticed since the early days of automobile development has not
+been for solely increasing the power of the engine, but to secure a more
+even turning movement, greater flexibility and to eliminate destructive
+vibration. The ideal internal combustion motor, is the one having the
+most uniform turning movement with the least mechanical friction loss.
+Study of the torque outlines or plotted graphics shown at Figs. 25 and
+30 will show how multiplication of cylinders will produce steady power
+delivery due to overlapping impulses. The most practical form would be
+that which more nearly conforms to the steady running produced by a
+steam turbine or electric motor. The advocates of the eight-cylinder
+engine bring up the item of uniform torque as one of the most important
+advantages of the eight-cylinder design. A number of torque diagrams are
+shown at Fig. 30. While these appear to be deeply technical, they may be
+very easily followed when their purpose is explained. At the top is
+shown the torque diagram of a single-cylinder motor of the four-cycle
+type. The high point in the line represents the period of greatest
+torque or power generation, and it will be evident that this occurs
+early in the first revolution of the crank-shaft. Below this diagram is
+shown a similar curve except that it is produced by a four-cylinder
+engine. Inspection will show that the turning-moment is much more
+uniform than in the single cylinder; similarly, the six-cylinder
+diagram is an improvement over the four, and the eight-cylinder diagram
+is an improvement over the six-cylinder.
+
+[Illustration: Fig. 31.--Diagrams Showing How Increasing Number of
+Cylinders Makes for More Uniform Power Application.]
+
+The reason that practically continuous torque is obtained in an
+eight-cylinder engine is that one cylinder fires every ninety degrees of
+crank-shaft rotation, and as each impulse lasts nearly seventy-five per
+cent. of the stroke, one can easily appreciate that an engine that will
+give four explosions per revolution of the crank-shaft will run more
+uniformly than one that gives but three explosions per revolution, as
+the six-cylinder does, and will be twice as smooth running as a
+four-cylinder, in which but two explosions occur per revolution of the
+crank-shaft. The comparison is so clearly shown in graphical diagrams
+and in Fig. 31 that further description is unnecessary.
+
+Any eight-cylinder engine may be considered a "twin-four,"
+twelve-cylinder engines may be considered "twin sixes."
+
+[Illustration: Fig. 32.--How the Angle Between the Cylinders of an
+Eight- and Twelve-Cylinder V Motor Varies.]
+
+The only points in which an eight-cylinder motor differs from a
+four-cylinder is in the arrangement of the connecting rod, as in many
+designs it is necessary to have two rods working from the same
+crank-pin. This difficulty is easily overcome in some designs by
+staggering the cylinders and having the two connecting rod big ends of
+conventional form side by side on a common crank-pin. In other designs
+one rod is a forked form and works on the outside of a rod of the
+regular pattern. Still another method is to have a boss just above the
+main bearing on one connecting rod to which the lower portion of the
+connecting rod in the opposite cylinder is hinged. As the eight-cylinder
+engine may actually be made lighter than the six-cylinder of equal
+power, it is possible to use smaller reciprocating parts, such as
+pistons, connecting rods and valve gear, and obtain higher engine speed
+with practically no vibration. The firing order in nearly every case is
+the same as in a four-cylinder except that the explosions occur
+alternately in each set of cylinders. The firing order of an
+eight-cylinder motor is apt to be confusing to the motorist,
+especially if one considers that there are eight possible sequences. The
+majority of engineers favor the alternate firing from side to side.
+Firing orders will be considered in proper sequence.
+
+[Illustration: Fig. 33.--The Hall-Scott Four-Cylinder 100 Horse-Power
+Aviation Motor.]
+
+[Illustration: Fig. 34.--Two Views of the Duesenberg Sixteen Valve
+Four-Cylinder Aviation Motor.]
+
+The demand of aircraft designers for more power has stimulated designers
+to work out twelve-cylinder motors. These are high-speed motors
+incorporating all recent features of design in securing light
+reciprocating parts, large valve openings, etc. The twelve-cylinder
+motor incorporates the best features of high-speed motor design and
+there is no need at this time to discuss further the pros and cons of
+the twelve-cylinder versus the eight or six, because it is conceded by
+all that there is the same degree of steady power application in the
+twelve over the eight as there would be in the eight over the six. The
+question resolves itself into having a motor of high power that will
+run with minimum vibration and that produces smooth action. This is well
+shown by diagrams at Fig. 31. It should be remembered that if an
+eight-cylinder engine will give four explosions per revolution of the
+fly-wheel, a twelve-cylinder type will give six explosions per
+revolution, and instead of the impulses coming 90 degrees crank travel
+apart, as in the case of the eight-cylinder, these will come but 60
+degrees of crank travel apart in the case of the twelve-cylinder. For
+this reason, the cylinders of a twelve are usually separated by 60
+degrees while the eight has the blocks spaced 90 degrees apart. The
+comparison can be easily made by comparing the sectional views of Vee
+engines at Fig. 32. When one realizes that the actual duration of the
+power stroke is considerably greater than 120 degrees crank travel, it
+will be apparent that the overlapping of explosions must deliver a very
+uniform application of power. Vee engines have been devised having the
+cylinders spaced but 45 degrees apart, but the explosions cannot be
+timed at equal intervals as when 90 degrees separate the cylinder center
+lines.
+
+[Illustration: Fig. 35.--The Hall-Scott Six-Cylinder Aviation Engine.]
+
+
+RADIAL CYLINDER ARRANGEMENTS
+
+[Illustration: Fig. 36.--The Curtiss Eight-Cylinder, 200 Horse-Power
+Aviation Engine.]
+
+While the fixed cylinder forms of engines, having the cylinders in
+tandem in the four- and six-cylinder models as shown at Figs. 33 to 35
+inclusive and the eight-cylinder V types as outlined at Figs. 36 and 37
+have been generally used and are most in favor at the present time,
+other forms of motors having unconventional cylinder arrangements have
+been devised, though most of these are practically obsolete. While many
+methods of decreasing weight and increasing mechanical efficiency of a
+motor are known to designers, one of the first to be applied to the
+construction of aeronautical power plants was an endeavor to group the
+components, which in themselves were not extremely light, into a form
+that would be considerably lighter than the conventional design. As an
+example, we may consider those multiple-cylinder forms in which the
+cylinders are disposed around a short crank-case, either radiating from
+a common center as at Fig. 38 or of the fan shape shown at Fig. 39. This
+makes it possible to use a crank-case but slightly larger than that
+needed for one or two cylinders and it also permits of a corresponding
+decrease in length of the crank-shaft. The weight of the engine is
+lessened because of the reduction in crank-shaft and crank-case weight
+and the elimination of a number of intermediate bearings and their
+supporting webs which would be necessary with the usual tandem
+construction. While there are six power impulses to every two
+revolutions of the crank-shaft, in the six-cylinder engine, they are
+not evenly spaced as is possible with the conventional arrangement.
+
+[Illustration: Fig. 37.--The Sturtevant Eight-Cylinder, High Speed
+Aviation Motor.]
+
+[Illustration: Fig. 38.--Anzani 40-50 Horse-Power Five-Cylinder Air
+Cooled Engine.]
+
+In the Anzani form, which is shown at Fig. 38, the crank-case is
+stationary and a revolving crank-shaft is employed as in conventional
+construction. The cylinders are five in number and the engine develops
+40 to 50 H.P. with a weight of 72 kilograms or 158.4 lbs. The cylinders
+are of the usual air-cooled form having cooling flanges only part of the
+way down the cylinder. By using five cylinders it is possible to have
+the power impulses come regularly, they coming 145 deg. crank-shaft
+travel apart, the crank-shaft making two turns to every five explosions.
+The balance is good and power output regular. The valves are placed
+directly in the cylinder head and are operated by a common pushrod.
+Attention is directed to the novel method of installing the carburetor
+which supplies the mixture to the engine base from which inlet pipes
+radiate to the various cylinders. This engine is used on French school
+machines.
+
+[Illustration: Fig. 39.--Unconventional Six-Cylinder Aircraft Motor of
+Masson Design.]
+
+In the form shown at Fig. 39 six cylinders are used, all being placed
+above the crank-shaft center line. This engine is also of the air-cooled
+form and develops 50 H. P. and weighs 105 kilograms, or 231 lbs. The
+carburetor is connected to a manifold casting attached to the engine
+base from which the induction pipes radiate to the various cylinders.
+The propeller design and size relative to the engine is clearly shown in
+this view. While flights have been made with both of the engines
+described, this method of construction is not generally followed and has
+been almost entirely displaced abroad by the revolving motors or by the
+more conventional eight-cylinder V engines. Both of the engines shown
+were designed about eight years ago and would be entirely too small and
+weak for use in modern airplanes intended for active duty.
+
+
+ROTARY ENGINES
+
+[Illustration: Fig. 40.--The Gnome Fourteen-Cylinder Revolving Motor.]
+
+Rotary engines such as shown at Fig. 40 are generally associated with
+the idea of light construction and it is rather an interesting point
+that is often overlooked in connection with the application of this idea
+to flight motors, that the reason why rotary engines are popularly
+supposed to be lighter than the others is because they form their own
+fly-wheel, yet on aeroplanes, engines are seldom fitted with a fly-wheel
+at all. As a matter of fact the Gnome engine is not so light because it
+is a rotary motor, and it is a rotary motor because the design that has
+been adopted as that most conducive to lightness is also most suited to
+an engine working in this way. The cylinders could be fixed and
+crank-shaft revolve without increasing the weight to any extent. There
+are two prime factors governing the lightness of an engine, one being
+the initial design, and the other the quality of the materials employed.
+The consideration of reducing weight by cutting away metal is a
+subsidiary method that ought not to play a part in standard practice,
+however useful it may be in special cases. In the Gnome rotary engine
+the lightness is entirely due to the initial design and to the materials
+employed in manufacture. Thus, in the first case, the engine is a radial
+engine, and has its seven or nine cylinders spaced equally around a
+crank-chamber that is no wider or rather longer than would be required
+for any one of the cylinders. This shortening of the crank-chamber not
+only effects a considerable saving of weight on its own account, but
+there is a corresponding saving in the shafts and other members, the
+dimensions of which are governed by the size of the crank-chamber. With
+regard to materials, nothing but steel is used throughout, and most of
+the metal is forged chrome nickel steel. The beautifully steady running
+of the engine is largely due to the fact that there are literally no
+reciprocating parts in the absolute sense, the apparent reciprocation
+between the pistons and cylinders being solely a relative reciprocation
+since both travel in circular paths, that of the pistons, however, being
+electric by one-half of the stroke length to that of the cylinder.
+
+While the Gnome engine has many advantages, on the other hand the head
+resistance offered by a motor of this type is considerable; there is a
+large waste of lubricating oil due to the centrifugal force which tends
+to throw the oil away from the cylinders; the gyroscopic effect of the
+rotary motor is detrimental to the best working of the aeroplane, and
+moreover it requires about seven per cent. of the total power developed
+by the motor to drive the revolving cylinders around the shaft. Of
+necessity, the compression of this type of motor is rather low, and an
+additional disadvantage manifests itself in the fact that there is as
+yet no satisfactory way of muffling the rotary type of motor. The modern
+Gnome engine has been widely copied in various European countries, but
+its design was originated in America, the early Adams-Farwell engine
+being the pioneer form. It has been made in seven- and nine-cylinder
+types and forms of double these numbers. The engine illustrated at Fig.
+40 is a fourteen-cylinder form. The simple engines have an odd number of
+cylinders in order to secure evenly spaced explosions. In the
+seven-cylinder, the impulses come 102.8 deg. apart. In the nine-cylinder
+form, the power strokes are spaced 80 deg. apart. The fourteen-cylinder
+engine is virtually two seven-cylinder types mounted together, the
+cranks being just the same as in a double cylinder opposed motor, the
+explosions coming 51.4 deg. apart; while in the eighteen-cylinder model the
+power impulses come every 40 deg. cylinder travel. Other rotary motors have
+been devised, such as the Le Rhone and the Clerget in France and several
+German copies of these various types. The mechanical features of these
+motors will be fully considered later.
+
+
+
+
+CHAPTER V
+
+ Properties of Liquid Fuels--Distillates of Crude Petroleum--
+ Principles of Carburetion Outlined--Air Needed to Burn Gasoline
+ --What a Carburetor Should Do--Liquid Fuel Storage and Supply--
+ Vacuum Fuel Feed--Early Vaporizer Forms--Development of Float
+ Feed Carburetor--Maybach's Early Design--Concentric Float and
+ Jet Type--Schebler Carburetor--Claudel Carburetor--Stewart
+ Metering Pin Type--Multiple Nozzle Vaporizers--Two-Stage
+ Carburetor--Master Multiple Jet Type--Compound Nozzle Zenith
+ Carburetor--Utility of Gasoline Strainers--Intake Manifold
+ Design and Construction--Compensating for Various Atmospheric
+ Conditions--How High Altitude Affects Power--The Diesel System--
+ Notes on Carburetor Installation--Notes on Carburetor
+ Adjustment.
+
+
+There is no appliance that has more material value upon the efficiency
+of the internal combustion motor than the carburetor or vaporizer which
+supplies the explosive gas to the cylinders. It is only in recent years
+that engineers have realized the importance of using carburetors that
+are efficient and that are so strongly and simply made that there will
+be little liability of derangement. As the power obtained from the
+gas-engine depends upon the combustion of fuel in the cylinders, it is
+evident that if the gas supplied does not have the proper proportions of
+elements to insure rapid combustion the efficiency of the engine will be
+low. When a gas engine is used as a stationary installation it is
+possible to use ordinary illuminating or natural gas for fuel, but when
+this prime mover is applied to automobiles or airplanes it is evident
+that considerable difficulty would be experienced in carrying enough
+compressed coal gas to supply the engine for even a very short trip.
+Fortunately, the development of the internal-combustion motor was not
+delayed by the lack of suitable fuel.
+
+Engineers were familiar with the properties of certain liquids which
+gave off vapors that could be mixed with air to form an explosive gas
+which burned very well in the engine cylinders. A very small quantity of
+such liquids would suffice for a very satisfactory period of operation.
+The problem to be solved before these liquids could be applied in a
+practical manner was to evolve suitable apparatus for vaporizing them
+without waste. Among the liquids that can be combined with air and
+burned, gasoline is the most volatile and is the fuel utilized by
+internal-combustion engines.
+
+The widely increasing scope of usefulness of the internal-combustion
+motor has made it imperative that other fuels be applied in some
+instances because the supply of gasoline may in time become inadequate
+to supply the demand. In fact, abroad this fuel sells for fifty to two
+hundred per cent. more than it does in America because most of the
+gasoline used must be imported from this country or Russia. Because of
+this foreign engineers have experimented widely with other substances,
+such as alcohol, benzol, and kerosene, but more to determine if they can
+be used to advantage in motor cars than in airplane engines.
+
+
+DISTILLATES OF CRUDE PETROLEUM
+
+Crude petroleum is found in small quantities in almost all parts of the
+world, but a large portion of that produced commercially is derived from
+American wells. The petroleum obtained in this country yields more of
+the volatile products than those of foreign production, and for that
+reason the demand for it is greater. The oil fields of this country are
+found in Pennsylvania, Indiana, and Ohio, and the crude petroleum is
+usually in association with natural gas. This mineral oil is an agent
+from which many compounds and products are derived, and the products
+will vary from heavy sludges, such as asphalt, to the lighter and more
+volatile components, some of which will evaporate very easily at
+ordinary temperatures.
+
+The compounds derived from crude petroleum are composed principally of
+hydrogen and carbon and are termed "Hydrocarbons." In the crude product
+one finds many impurities, such as free carbon, sulphur, and various
+earthy elements. Before the oil can be utilized it must be subjected to
+a process of purifying which is known as refining, and it is during this
+process, which is one of destructive distillation, that the various
+liquids are separated. The oil was formerly broken up into three main
+groups of products as follows: Highly volatile, naphtha, benzine,
+gasoline, eight to ten per cent. Light oils, such as kerosene and light
+lubricating oils seventy to eighty per cent. Heavy oils or residuum five
+to nine per cent. From the foregoing it will be seen that the available
+supply of gasoline is determined largely by the demand existing for the
+light oils forming the larger part of the products derived from crude
+petroleum. New processes have been recently discovered by which the
+lighter oils, such as kerosene, are reduced in proportion and that of
+gasoline increased, though the resulting liquid is neither the high
+grade, volatile gasoline known in the early days of motoring nor the low
+grade kerosene.
+
+
+PRINCIPLES OF CARBURETION OUTLINED
+
+The process of carburetion is combining the volatile vapors which
+evaporate from the hydrocarbon liquids with certain proportions of air
+to form an inflammable gas. The quantities of air needed vary with
+different liquids and some mixtures burn quicker than do other
+combinations of air and vapor. Combustion is simply burning and it may
+be rapid, moderate or slow. Mixtures of gasoline and air burn quickly,
+in fact the combustion is so rapid that it is almost instantaneous and
+we obtain what is commonly termed an "explosion." Therefore the
+explosion of gas in the automobile engine cylinder which produces the
+power is really a combination of chemical elements which produce heat
+and an increase in the volume of the gas because of the increase in
+temperature.
+
+If the gasoline mixture is not properly proportioned the rate of
+burning will vary, and if the mixture is either too rich or too weak the
+power of the explosion is reduced and the amount of power applied to the
+piston is decreased proportionately. In determining the proper
+proportions of gasoline and air, one must take the chemical composition
+of gasoline into account. The ordinary liquid used for fuel is said to
+contain about eight-four per cent. carbon and sixteen per cent.
+hydrogen. Air is composed of oxygen and nitrogen and the former has a
+great affinity, or combining power, with the two constituents of
+hydrocarbon liquids. Therefore, what we call an explosion is merely an
+indication that oxygen in the air has combined with the carbon and
+hydrogen of the gasoline.
+
+
+AIR NEEDED TO BURN GASOLINE
+
+In figuring the proper volume of air to mix with a given quantity of
+fuel, one takes into account the fact that one pound of hydrogen
+requires eight pounds of oxygen to burn it, and one pound of carbon
+needs two and one-third pounds of oxygen to insure its combustion. Air
+is composed of one part of oxygen to three and one-half portions of
+nitrogen by weight. Therefore for each pound of oxygen one needs to burn
+hydrogen or carbon four and one-half pounds of air must be allowed. To
+insure combustion of one pound of gasoline which is composed of hydrogen
+and carbon we must furnish about ten pounds of air to burn the carbon
+and about six pounds of air to insure combustion of hydrogen, the other
+component of gasoline. This means that to burn one pound of gasoline one
+must provide about sixteen pounds of air.
+
+While one does not usually consider air as having much weight, at a
+temperature of sixty-two degrees Fahrenheit about fourteen cubic feet of
+air will weigh a pound, and to burn a pound of gasoline one would
+require about two hundred cubic feet of air. This amount will provide
+for combustion theoretically, but it is common practice to allow twice
+this amount because the element nitrogen, which is the main constituent
+of air, is an inert gas and instead of aiding combustion it acts as a
+deterrent of burning. In order to be explosive, gasoline vapor must be
+combined with definite quantities of air. Mixtures that are rich in
+gasoline ignite quicker than those which have more air, but these are
+only suitable when starting or when running slowly, as a rich mixture
+ignites much quicker than a weak mixture. The richer mixture of gasoline
+and air not only burns quicker but produces the most heat and the most
+effective pressure in pounds per square inch of piston top area.
+
+The amount of compression of the charge before ignition also has
+material bearing on the force of the explosion. The higher the degree of
+compression the greater the force exerted by the rapid combustion of the
+gas. It may be stated that as a general thing the maximum explosive
+pressure is somewhat more than four times the compression pressure prior
+to ignition. A charge compressed to sixty pounds will have a maximum of
+approximately two hundred and forty pounds; compacted to eighty pounds
+it will produce a pressure of about three hundred pounds on each square
+inch of piston area at the beginning of the power stroke. Mixtures
+varying from one part of gasoline vapor to four of air to others having
+one part of gasoline vapor to thirteen of air can be ignited, but the
+best results are obtained when the proportions are one to five or one to
+seven, as this mixture is said to be the one that will produce the
+highest temperature, the quickest explosion, and the most pressure.
+
+
+WHAT A CARBURETOR SHOULD DO
+
+While it is apparent that the chief function of a carbureting device is
+to mix hydrocarbon vapors with air to secure mixtures that will burn,
+there are a number of factors which must be considered before describing
+the principles of vaporizing devices. Almost any device which permits a
+current of air to pass over or through a volatile liquid will produce a
+gas which will explode when compressed and ignited in the motor
+cylinder. Modern carburetors are not only called upon to supply certain
+quantities of gas, but these must deliver a mixture to the cylinders
+that is accurately proportioned and which will be of proper composition
+at all engine speeds.
+
+[Illustration: Fig. 41.--How Gravity Feed Fuel Tank May Be Mounted Back
+of Engine and Secure Short Fuel Line.]
+
+Flexible control of the engine is sought by varying the engine speed by
+regulating the supply of gas to the cylinders. The power plant should
+run from its lowest to its highest speed without any irregularity in
+torque, i.e., the acceleration should be gradual rather than spasmodic.
+As the degree of compression will vary in value with the amount of
+throttle opening, the conditions necessary to obtain maximum power
+differ with varying engine speeds. When the throttle is barely opened
+the engine speed is low and the gas must be richer in fuel than when the
+throttle is wide open and the engine speed high.
+
+When an engine is turning over slowly the compression has low value and
+the conditions are not so favorable to rapid combustion as when the
+compression is high. At high engine speeds the gas velocity through the
+intake piping is higher than at low speeds, and regular engine action is
+not so apt to be disturbed by condensation of liquid fuel in the
+manifold due to excessively rich mixture or a superabundance of liquid
+in the stream of carbureted air.
+
+
+LIQUID FUEL STORAGE AND SUPPLY
+
+The problem of gasoline storage and method of supplying the carburetor
+is one that is determined solely by design of the airplane. While the
+object of designers should be to supply the fuel to the carburetor by as
+simple means as possible the fuel supply system of some airplanes is
+quite complex. The first point to consider is the location of the
+gasoline tank. This depends upon the amount of fuel needed and the space
+available in the fuselage.
+
+A very simple and compact fuel supply system is shown at Fig. 41. In
+this instance the fuel container is placed immediately back of the
+engine cylinder. The carburetor which is carried as indicated is joined
+to the tank by a short piece of copper or flexible rubber tubing. This
+is the simplest possible form of fuel supply system and one used on a
+number of excellent airplanes.
+
+As the sizes of engines increase and the power plant fuel consumption
+augments it is necessary to use more fuel, and to obtain a satisfactory
+flying radius without frequent landings for filling the fuel tank it is
+necessary to supply large containers.
+
+When a very powerful power plant is fitted, as on battle planes of high
+capacity, it is necessary to carry large quantities of gasoline. In
+order to use a tank of sufficiently large capacity it may be necessary
+to carry it lower than the carburetor. When installed in this manner it
+is necessary to force fuel out of the tank by air pressure or to pump it
+with a vacuum tank because the gasoline tank is lower than the
+carburetor it supplies and the gasoline cannot flow by gravity as in the
+simpler systems. While the pressure and gravity feed systems are
+generally used in airplanes, it may be well to describe the vacuum lift
+system which has been widely applied to motor cars and which may have
+some use in connection with airplanes as these machines are developed.
+
+
+STEWART VACUUM FUEL FEED
+
+One of the marked tendencies has been the adoption of a vacuum fuel feed
+system to draw the gasoline from tanks placed lower than the carburetor
+instead of using either exhaust gas or air pressure to achieve this end.
+The device generally fitted is the Stewart vacuum feed tank which is
+clearly shown in section at Fig. 42. In this system the suction of a
+motor is employed to draw gasoline from the main fuel tank to the
+auxiliary tank incorporated in the device and from this tank the liquid
+flows to the carburetor. It is claimed that all the advantages of the
+pressure system are obtained with very little more complication than is
+found on the ordinary gravity feed. The mechanism is all contained in
+the cylindrical tank shown, which may be mounted either on the front of
+the dash or on the side of the engine as shown.
+
+[Illustration: Fig. 42.--The Stewart Vacuum Fuel Feed Tank.]
+
+The tank is divided into two chambers, the upper one being the filling
+chamber and the lower one the emptying chamber. The former, which is at
+the top of the device, contains the float valve, as well as the pipes
+running to the main fuel container and to the intake manifold. The lower
+chamber is used to supply the carburetor with gasoline and is under
+atmospheric pressure at all times, so the flow of fuel from it is by
+means of gravity only. Since this chamber is located somewhat above the
+carburetor, there must always be free flow of fuel. Atmospheric pressure
+is maintained by the pipes A and B, the latter opening into the air. In
+order that the fuel will be sucked from a main tank to the upper
+chamber, the suction valve must be opened and the atmospheric valve
+closed. Under these conditions the float is at the bottom and the
+suction at the intake manifold produces a vacuum in the tank which draws
+the gasoline from the main tank to the upper chamber. When the upper
+chamber is filled at the proper height the float rises to the top, this
+closing the suction valve and opening the atmospheric valve. As the
+suction is now cut off, the lower chamber is filled by gravity owing to
+there being atmospheric pressure in both upper and lower chambers. A
+flap valve is provided between the two chambers to prevent the gasoline
+in the lower one from being sucked back into the upper one. The
+atmospheric and suction valves are controlled by the levers C and D,
+both of which are pivoted at E, their outer ends being connected by two
+coil springs. It is seen that the arrangement of these two springs is
+such that the float must be held at the extremity of its movement, and
+that it cannot assume an intermediate position.
+
+This intermittent action is required to insure that the upper part of
+the tank may be under atmospheric pressure part of the time for the
+gasoline to flow to the lower chamber. When the level of gasoline drops
+to a certain point, the float falls, thus opening the suction valve and
+closing the atmospheric valve. The suction of the motor then causes a
+flow of fuel from the main container. As soon as the level rises to the
+proper height the float returns to its upper position. It takes about
+two seconds for the chamber to become full enough to raise the float, as
+but .05 gallon is transferred at a time. The pipe running from the
+bottom of the lower chamber to the carburetor extends up a ways, so that
+there is but little chance of dirt or water being carried to the float
+chamber.
+
+If the engine is allowed to stand long enough so that the tank becomes
+empty, it will be replenished after the motor has been cranked over four
+or five times with the throttle closed. The installation of the Stewart
+Vacuum-Gravity System is very simple. The suction pipe is tapped into
+the manifold at a point as near the cylinders as possible, while the
+fuel pipe is inserted into the gasoline tank and runs to the bottom of
+that member. There is a screen at the end of the fuel pipe to prevent
+any trouble due to deposits of sediment in the main container. As the
+fuel is sucked from the gasoline tank a small vent must be made in the
+tank filler cap so that the pressure in the main tank will always be
+that of the atmosphere.
+
+
+EARLY VAPORIZER FORMS
+
+The early types of carbureting devices were very crude and cumbersome,
+and the mixture of gasoline vapor and air was accomplished in three
+ways. The air stream was passed over the surface of the liquid itself,
+through loosely placed absorbent material saturated with liquid, or
+directly through the fuel. The first type is known as the surface
+carburetor and is now practically obsolete. The second form is called
+the "wick" carburetor because the air stream was passed over or through
+saturated wicking. The third form was known as a "bubbling" carburetor.
+While these primitive forms gave fairly good results with the early
+slow-speed engines and the high grade, or very volatile, gasoline which
+was first used for fuel, they would be entirely unsuitable for present
+forms of engines because they would not carburate the lower grades of
+gasoline which are used to-day, and would not supply the modern
+high-speed engines with gas of the proper consistency fast enough even
+if they did not have to use very volatile gasoline. The form of
+carburetor used at the present time operates on a different principle.
+These devices are known as "spraying carburetors." The fuel is reduced
+to a spray by the suction effect of the entering air stream drawing it
+through a fine opening.
+
+The advantage of this construction is that a more thorough amalgamation
+of the gasoline and air particles is obtained. With the earlier types
+previously considered the air would combine with only the more volatile
+elements, leaving the heavier constituents in the tank. As the fuel
+became stale it was difficult to vaporize it, and it had to be drained
+off and fresh fuel provided before the proper mixture would be produced.
+It will be evident that when the fuel is sprayed into the air stream,
+all the fuel will be used up and the heavier portions of the gasoline
+will be taken into the cylinder and vaporized just as well as the more
+volatile vapors.
+
+[Illustration: Fig. 43.--Marine-Type Mixing Valve, by which Gasoline is
+Sprayed into Air Stream Through Small Opening in Air-Valve Seat.]
+
+The simplest form of spray carburetor is that shown at Fig. 43. In this
+the gasoline opening through which the fuel is sprayed into the
+entering air stream is closed by the spring-controlled mushroom valve
+which regulates the main air opening as well. When the engine draws in a
+charge of air it unseats the valve and at the same time the air flowing
+around it is saturated with gasoline particles through the gasoline
+opening. The mixture thus formed goes to the engine through the mixture
+passage. Two methods of varying the fuel proportions are provided. One
+of these consists of a needle valve to regulate the amount of gasoline,
+the other is a knurled screw which controls the amount of air by
+limiting the lift of the jump valve.
+
+
+DEVELOPMENT OF FLOAT-FEED CARBURETOR
+
+The modern form of spraying carburetor is provided with two chambers,
+one a mixing chamber through which the air stream passes and mixes with
+a gasoline spray, the other a float chamber in which a constant level of
+fuel is maintained by simple mechanism. A jet or standpipe is used in
+the mixing chamber to spray the fuel through and the object of the float
+is to maintain the fuel level to such a point that it will not overflow
+the jet when the motor is not drawing in a charge of gas. With the
+simple forms of generator valve in which the gasoline opening is
+controlled by the air valve, a leak anywhere in either valve or valve
+seat will allow the gasoline to flow continuously whether the engine is
+drawing in a charge or not. The liquid fuel collects around the air
+opening, and when the engine inspires a charge it is saturated with
+gasoline globules and is excessively rich. With a float-feed
+construction, which maintains a constant level of gasoline at the right
+height in the standpipe, liquid fuel will only be supplied when drawn
+out of the jet by the suction effect of the entering air stream.
+
+
+MAYBACH'S EARLY DESIGN
+
+The first form of spraying carburetor ever applied successfully was
+evolved by Maybach for use on one of the earliest Daimler engines. The
+general principles of operation of this pioneer float-feed carburetor
+are shown at Fig. 44, A. The mixing chamber and valve chamber were one
+and the standpipe or jet protruded into the mixing chamber. It was
+connected to the float compartment by a pipe. The fuel from the tank
+entered the top of the float compartment and the opening was closed by a
+needle valve carried on top of a hollow metal float. When the level of
+gasoline in the float chamber was lowered the float would fall and the
+needle valve uncover the opening. This would permit the gasoline from
+the tank to flow into the float chamber, and as the chamber filled the
+float would rise until the proper level had been reached, under which
+conditions the float would shut off the gasoline opening. On every
+suction stroke of the engine the inlet valve, which was an automatic
+type, would leave its seat and a stream of air would be drawn through
+the air opening and around the standpipe or jet. This would cause the
+gasoline to spray out of the tube and mix with the entering air stream.
+
+[Illustration: Fig. 44.--Tracing Evolution of Modern Spray Carburetor.
+A--Early Form Evolved by Maybach. B.--Phoenix-Daimler Modification of
+Maybach's Principle. C--Modern Concentric Float Automatic Compensating
+Carburetor.]
+
+The form shown at B was a modification of Maybach's simple device and
+was first used on the Phoenix-Daimler engines. Several improvements are
+noted in this device. First, the carburetor was made one unit by casting
+the float and mixing chambers together instead of making them separate
+and joining them by a pipe, as shown at A. The float construction was
+improved and the gasoline shut-off valve was operated through leverage
+instead of being directly fastened to the float. The spray nozzle was
+surrounded by a choke tube which concentrated the air stream around it
+and made for more rapid air flow at low engine speeds. A conical piece
+was placed over the jet to break up the entering spray into a mist and
+insure more intimate admixture of air and gasoline. The air opening was
+provided with an air cone which had a shutter controlling the opening so
+that the amount of air entering could be regulated and thus vary the
+mixture proportions within certain limits.
+
+
+CONCENTRIC FLOAT AND JET TYPE
+
+The form shown at B has been further improved, and the type shown at C
+is representative of modern single jet practice. In this the float
+chamber and mixing chamber are concentric. A balanced float mechanism
+which insures steadiness of feed is used, the gasoline jet or standpipe
+is provided with a needle valve to vary the amount of gasoline supplied
+the mixture and two air openings are provided. The main air port is at
+the bottom of the vaporizer, while an auxiliary air inlet is provided at
+the side of the mixing chamber. There are two methods of controlling the
+mixture proportions in this form of carburetor. One may regulate the
+gasoline needle or adjust the auxiliary air valve.
+
+
+SCHEBLER CARBURETOR
+
+A Schebler carburetor, which has been used on some airplane engines, is
+shown in Fig. 45. It will be noticed that a metering pin or needle valve
+opens the jet when the air valve opens. The long arm of a leverage is
+connected to the air valve, while the short arm is connected to the
+needle, the reduction in leverage being such that the needle valve is
+made to travel much less than the air valve. For setting the amount of
+fuel passed or the size of the jet orifice when running with the air
+valve closed, there is a screw which raises or lowers the fulcrum of the
+lever and there is also a dash control having the same effect by pushing
+down the fulcrum against a small spring. A long extension is given to
+the venturi tube which is very narrow around the jet orifices, which are
+horizontal and shown at A in the drawing. Fuel enters the float chamber
+through the union M, and the spring P holds the metering pin upward
+against the restraining action of the lever. The air valve may be set by
+an easily adjustable knurled screw shown in the drawing, and fluttering
+of the valve is prevented by the piston dash pot carried in a chamber
+above the valve into which the valve stem projects. The primary air
+enters beneath the jet passage and there is a small throttle in the
+intake to increase the speed of air flow for starting purposes. The
+carburetor is adapted for the use of a hot-air connection to the stove
+around the exhaust pipe and it is recommended that such a fitting be
+supplied. The lever which controls the supply of air through the primary
+air intake is so arranged that if desired it can be connected with a
+linkage on the dash or control column by means of a flexible wire.
+
+[Illustration: Fig. 45.--New Model of Schebler Carburetor With Metering
+Valve and Extended Venturi. Note Mechanical Connection Between Air Valve
+and Fuel Regulating Needle.]
+
+
+THE CLAUDEL (FRENCH) CARBURETOR
+
+[Illustration: Fig. 46.--The Claudel Carburetor.]
+
+This carburetor is of extremely simple construction, because it has no
+supplementary or auxiliary air valve and no moving parts except the
+throttle controlling the gas flow. The construction is already shown in
+Fig. 46. The spray jet is eccentric with a surrounding sleeve or tube
+in which there are two series of small orifices, one at the top and the
+other near the bottom. The former are about level with the spray jet
+opening. The sleeve surrounding the nozzle is closed at the top. The
+air, passing the upper holes in the sleeve, produces a vacuum in the
+sleeve, thereby drawing air in through the bottom holes. It is this
+moving interior column of air that controls the flow of gasoline from
+the nozzle. Owing to the friction of the small passages, the speed of
+air flow through the sleeve does not increase as fast as the speed of
+air flow outside the sleeve, hence there is a tendency for the mixture
+to remain constant. The throttle of this carburetor is of the barrel
+type, and the top of the spray nozzle and its surrounding sleeve are
+located inside the throttle.
+
+
+STEWART METERING PIN CARBURETOR
+
+The carburetor shown at Fig. 47 is a metering type in which the vacuum
+at the jet is controlled by the weight of the metering valve surrounding
+the upright metering pin. The only moving part is the metering valve,
+which rises and falls with the changes in vacuum. The air chamber
+surrounds the metering valve, and there is a mixing chamber above. As
+the valve is drawn up the gasoline passage is enlarged on account of the
+predetermined taper on the metering pin, and the air passage also is
+increased proportionately, giving the correct mixture. A dashpot at the
+bottom of the valve checks flutter. In idling the valve rests on its
+seat, practically closing the air and giving the necessary idling
+mixture. A passage through the valve acts as an aspirating tube. When
+the valve is closed altogether the primary air passes through ducts in
+the valve itself, giving the proper amount for idling. The one
+adjustment consists in raising or lowering the tapered metering pin,
+increasing or decreasing the supply of gasoline. Dash control is
+supplied. This pulls down the metering pin, increasing the gasoline
+flow. The duplex type for eight- and twelve-cylinder motors is the same
+in principle as model 25, but it is a double carburetor synchronized as
+to throttle movements, adjustments, etc. The duplex for aeronautical
+motors is made of cast aluminum alloy.
+
+[Illustration: Fig. 47.--The Stewart Metering Pin Carburetor.]
+
+
+MULTIPLE NOZZLE VAPORIZERS
+
+To secure properly proportioned mixtures some carburetor designers have
+evolved forms in which two or more nozzles are used in a common mixing
+chamber. The usual construction is to use two, one having a small
+opening and placed in a small air tube and used only for low speeds,
+the other being placed in a larger air tube and having a slightly
+augmented bore so that it is employed on intermediate speeds. At high
+speeds both jets would be used in series. Some multiple jet carburetors
+could be considered as a series of these instruments, each one being
+designed for certain conditions of engine action. They would vary from
+small size just sufficient to run the engine at low speed to others
+having sufficient capacity to furnish gas for the highest possible
+engine speed when used in conjunction with the smaller members which
+have been brought into service progressively as the engine speed has
+been augmented. The multiple nozzle carburetor differs from that in
+which a single spray tube is used only in the construction of the mixing
+chamber, as a common float bowl can be used to supply all spray pipes.
+It is common practice to bring the jets into action progressively by
+some form of mechanical connection with the throttle or by automatic
+valves.
+
+The object of any multiple nozzle carburetor is to secure greater
+flexibility and endeavor to supply mixtures of proper proportions at all
+speeds of the engine. It should be stated, however, that while devices
+of this nature lend themselves readily to practical application it is
+more difficult to adjust them than the simpler forms having but one
+nozzle. When a number of jets are used the liability of clogging up the
+carburetor is increased, and if one or more of the nozzles is choked by
+a particle of dirt or water the resulting mixture trouble is difficult
+to detect. One of the nozzles may supply enough gasoline to permit the
+engine to run well at certain speeds and yet not be adequate to supply
+the proper amount of gas under other conditions. In adjusting a multiple
+jet carburetor in which the jets are provided with gasoline regulating
+needles, it is customary to consider each nozzle as a distinct
+carburetor and to regulate it to secure the best motor action at that
+throttle position which corresponds to the conditions under which the
+jet is brought into service. For instance, that supplied the primary
+mixing chamber should be regulated with the throttle partly closed,
+while the auxiliary jet should be adjusted with the throttle fully
+opened.
+
+
+BALL AND BALL TWO-STAGE CARBURETOR
+
+[Illustration: Fig. 48.--The Ball and Ball Two-Stage Carburetor.]
+
+This is a two-stage vaporizing device, hot air being used in the primary
+or initial stage of vaporization and cold air in the supplementary
+stage. Referring to the sectional illustration at Fig. 48, it will be
+seen that there is a hot-air passage with a choke-valve; the primary
+venturi appears at B; J is its gasoline jet, and V is a spring-loaded
+idling valve in a fixed air opening. These parts constitute the primary
+system. In the secondary system A is a cold-air passage, T a butterfly
+valve and J a gasoline jet discharging into the cold-air passage. This
+system is brought into operation by opening the butterfly T. A
+connection between the butterfly T and the throttle, not shown, throws
+the butterfly wide open when the throttle is not quite wide open; at all
+other times the butterfly is held closed by a spring. The cylindrical
+chamber at the right of the mixing chamber has an extension E of reduced
+diameter connecting it with the intake manifold through a passage D. A
+restricted opening connects the float chamber with the cylindrical
+chamber so that the gasoline level is the same in both. A loosely
+fitting plunger P in the cylindrical chamber has an upward extension
+into the small part of the chamber. O is a small air opening and M is a
+passage from the cylindrical chamber to the mixing chamber. Air
+constantly passes through this when the carburetor is in operation. The
+carburetor is really two in one. The primary carburetor is made up of a
+central jet in a venturi passage. The float chamber is eccentric. In the
+air passage there is a fixed opening, and additional air is taken in by
+the opening through suction of a spring-opposed air valve. The second
+stage, which comes into play as soon as the carburetor is called upon
+for additional mixture above low medium speeds, is made up of an
+independent air passage containing another air valve. As the valve is
+opened this jet is uncovered, and air is led past it. For easy starting
+an extra passage leads from the float bowl passage to a point above the
+throttle. All the suction falls upon this passage when the throttle is
+closed. The passage contains a plunger and acts as a pick-up device.
+When the vacuum increases the plunger rises and shuts off the flow of
+gasoline from the intake passage. As the throttle is opened the vacuum
+in the intake passage is broken, and the plunger falls, causing gasoline
+to gather above it. This is immediately drawn through the pick-up
+passage and gives the desired mixture for acceleration.
+
+
+MASTER MULTIPLE-JET CARBURETOR
+
+[Illustration: Fig. 49.--The Master Carburetor.]
+
+This carburetor, shown in detail in Figs. 49 and 50, has been very
+popular in racing cars and aviation engines because of exceptionally
+good pick-up qualities and its thorough atomization of fuel. Its
+principle of operation is the breaking up of the fuel by a series of
+jets, which vary in number from fourteen to twenty-one, according to
+the size of the carburetor. These are uncovered by opening the throttle,
+which is curved--a patented feature--to secure the correct progression
+of jets. The carburetor has an eccentric float chamber, from which the
+gasoline is led to the jet piece from which the jets stand up in a row.
+The tops of these jets are closed until the throttle is opened far
+enough to pass them, which it does progressively. The air opening is at
+the bottom, and the throttle opening is such that a modified venturi is
+formed. The throttle is carried in a cylindrical barrel with the jets
+placed below it, and the passage from the barrel to the intake is
+arranged so that there is no interruption in the flow. For easy starting
+a dash-controlled shutter closes off the air, throwing the suction on
+the jets, thus giving a rich mixture.
+
+[Illustration: Fig. 50.--Sectional View of Master Carburetor Showing
+Parts.]
+
+The only adjustment is for idling, and once that is fixed it need never
+be touched. This is in the form of a screw and regulates the position of
+the throttle when at idling position. The dash control has high-speed,
+normal and rich-starting positions. In installing the Master carburetor
+the float chamber may be turned either toward the radiator or driver's
+seat. If the float is turned toward the radiator, however, a forward lug
+plate should be ordered; otherwise it will be difficult to install the
+control. The throttle lever must go all the way to the stop lug or
+maximum power will not be secured. In adjusting the idle screw it is
+turned in for rich and out for lean.
+
+
+COMPOUND NOZZLE ZENITH CARBURETOR
+
+[Illustration: Fig. 51.--Sectional View of Zenith Compound Nozzle
+Compensating Carburetor.]
+
+The Zenith carburetor, shown at Fig. 51, has become very popular for
+airplane engine use because of its simplicity, as mixture compensation
+is secured by a compensating compound nozzle principle that works very
+well in practice. To illustrate this principle briefly, let us consider
+the elementary type of carburetor or mixing valve, as shown in Fig. 52,
+A. It consists of a single jet or spraying nozzle placed in the path of
+the incoming air and fed from the usual float chamber. It is a natural
+inference to suppose that as the speed of the motor increases, both the
+flow of air and of gasoline will increase in the same proportion.
+Unhappily, such is not the case. There is a law of liquid bodies which
+states that the flow of gasoline from the jet increases under suction
+faster than the flow of air, giving a mixture which grows richer and
+richer--a mixture containing a much higher percentage of gasoline at
+high suction than at low. The tendency is shown by the accompanying
+curve (Fig. 52, B), which gives the ratio of gasoline to air at varying
+speeds from this type of jet. The mixture is practically constant only
+between narrow limits and at very high speed. The most common method of
+correcting this defect is by putting various auxiliary air valves which,
+adding air, tends to dilute this mixture as it gets too rich. It is
+difficult with makeshift devices to gauge this dilution accurately for
+every motor speed.
+
+[Illustration: Fig. 52.--Diagrams Explaining Action of Baverey Compound
+Nozzle Used in Zenith Carburetor.]
+
+Now, if we have a jet which grows richer as the suction increases, the
+opposite type of jet is one which would grow leaner under similar
+conditions. Baverey, the inventor of the Zenith, discovered the
+principle of the constant flow device which is shown in Fig. 52, C. Here
+a certain fixed amount of gasoline determined by the opening I is
+permitted to flow by gravity into the well J open to the air. The
+suction at jet H has no effect upon the gravity compensator I because
+the suction is destroyed by the open well J. The compensator, then,
+delivers a steady rate of flow per unit of time, and as the motor
+suction increases more air is drawn up, while the amount of gasoline
+remains the same and the mixture grows poorer and poorer. Fig. 52, D,
+shows this curve.
+
+By combining these two types of rich and poor mixture carburetors the
+Zenith compound nozzle was evolved. In Fig. 52, E, we have both the
+direct suction or richer type leading through pipe E and nozzle G and
+the "constant flow" device of Baverey shown at J, I, K and nozzle H. One
+counteracts the defects of the other, so that from the cranking of the
+motor to its highest speed there is a constant ratio of air and
+gasoline to supply efficient combustion.
+
+In addition to the compound nozzle the Zenith is equipped with a
+starting and idling well, shown in the cut of Model L carburetor at P
+and J. This terminates in a priming hole at the edge of the butterfly
+valve, where the suction is greatest when this valve is slightly open.
+The gasoline is drawn up by the suction at the priming hole and, mixed
+with the air rushing by the butterfly, gives an ideal slow speed
+mixture. At higher speeds with the butterfly valve opened further the
+priming well ceases to operate and the compound nozzle drains the well
+and compensates correctly for any motor speed.
+
+[Illustration: Fig. 53.--The Zenith Duplex Carburetor for Airplane
+Motors of the V Type.]
+
+With the coming of the double motor containing eight or twelve cylinders
+arranged in two V blocks, the question of good carburetion has been a
+problem requiring much study. The single carburetor has given only
+indifferent results due to the strong cross suction in the inlet
+manifold from one set of cylinders to the other. This naturally led to
+the adoption of two carburetors in which each set of cylinders was
+independently fed by a separate carburetor. Results from this system
+were very good when the two carburetors were working exactly in unison,
+but as it was extremely difficult to accomplish this co-operation,
+especially where the adjustable type was employed, this system never
+gained in favor. The next logical step was the Zenith Duplex, shown at
+Fig. 53. This consists of two separate and distinct carburetors joined
+together so that a common gasoline float chamber and air inlet could be
+used by both. It does away with cross suction in the manifold because
+each set of cylinders has a separate intake of its own. It does away
+with two carburetors and makes for simplicity. The practical application
+of the Zenith carburetor to the Curtiss 90 horse-power OX-2 motor used
+on the JN-4 standard training machine is shown at Fig. 54, which
+outlines a rear view of the engine in question. The carburetor is
+carried low to permit of fuel supply from a gravity tank carried back of
+the motor.
+
+[Illustration: Fig. 54.--Rear View of Curtiss OX-2 90 Horse-Power
+Airplane Motor Showing Carburetor Location and Hot Air Leads.]
+
+
+UTILITY OF GASOLINE STRAINERS
+
+Many carburetors include a filtering screen at the point where the
+liquid enters the float chamber in order to keep dirt or any other
+foreign matter which may be present in the fuel from entering the float
+chamber. This is not general practice, however, and the majority of
+vaporizers do not include a filter in their construction. It is very
+desirable that the dirt should be kept out of the carburetor because it
+may get under the float control fuel valve and cause flooding by keeping
+it raised from its seat. If it finds its way into the spray nozzle it
+may block the opening so that no gasoline will issue or may so constrict
+the passage that only very small quantities of fuel will be supplied the
+mixture. Where the carburetor itself is not provided with a filtering
+screen a simple filter is usually installed in the pipe line between the
+gasoline tank and the float chamber.
+
+Some simple forms of filters and separators are shown at Fig. 55. That
+at A consists of a simple brass casting having a readily detachable
+gauze screen and a settling chamber of sufficient capacity to allow the
+foreign matter to settle to the bottom, from which it is drained out by
+a pet cock. Any water or dirt in the gasoline will settle to the bottom
+of the chamber, and as all fuel delivered to the carburetor must pass
+through the wire gauze screen it is not likely to contain impurities
+when it reaches the float chamber. The heavier particles, such as scale
+from the tank or dirt and even water, all of which have greater weight
+than the gasoline, will sink to the bottom of the chamber, whereas
+light particles, such as lint, will be prevented from flowing into the
+carburetor by the filtering screen.
+
+[Illustration: Fig. 55.--Types of Strainers Interposed Between Vaporizer
+and Gasoline Tank to Prevent Water or Dirt Passing Into Carbureting
+Device.]
+
+The filtering device shown at B is a larger appliance than that shown at
+A, and should be more efficient as a separator because the gasoline is
+forced to pass through three filtering screens before it reaches the
+carburetor. The gasoline enters the device shown at C through a bent
+pipe which leads directly to the settling chamber and from thence
+through a wire gauze screen to the upper compartment which leads to the
+carburetor. The device shown at D is a combination strainer, drain, and
+sediment cup. The filtering screen is held in place by a spring and
+both are removed by taking out a plug at the bottom of the device. The
+shut-off valve at the top of the device is interposed between the
+sediment cup and the carburetor. This separating device is incorporated
+with the gasoline tank and forms an integral part of the gasoline supply
+system. The other types shown are designed to be interposed between the
+gasoline tank and the carburetor at any point in the pipe line where
+they may be conveniently placed.
+
+
+INTAKE MANIFOLD DESIGN AND CONSTRUCTION
+
+On four- and six-cylinder engines and in fact on all multiple-cylinder
+forms, it is important that the piping leading from the carburetor to
+the cylinders be made in such a way that the various cylinders will
+receive their full quota of gas and that each cylinder will receive its
+charge at about the same point in the cycle of operations. In order to
+make the passages direct the bends should be as few as possible, and
+when curves are necessary they should be of large radius because an
+abrupt corner will not only impede gas flow but will tend to promote
+condensation of the fuel. Every precaution should be taken with
+four- and six-cylinder engines to insure equitable gas distribution to
+the valve chambers if regular action of the power plant is desired. If
+the gas pipe has many turns and angles it will be difficult to charge
+all cylinders properly. On some six-cylinder aviation engines, two
+carburetors are used because of trouble experienced with manifolds
+designed for one carburetor. Duplex carburetors are necessary to secure
+the best results from eight- and twelve-cylinder V engines.
+
+The problem of intake piping is simplified to some extent on block
+motors where the intake passage is cored in the cylinder casting and
+where but one short pipe is needed to join this passage to the
+carburetor. If the cylinders are cast in pairs a simple pipe of T or Y
+form can be used with success. When the engine is of a type using
+individual cylinder castings, especially in the six-cylinder power
+plants, the proper application and installation of suitable piping is a
+difficult problem. The reader is referred to the various engine designs
+outlined to ascertain how the inlet piping has been arranged on
+representative aviation engines. Intake piping is constructed in two
+ways, the most common method being to cast the manifold of brass or
+aluminum. The other method, which is more costly, is to use a built-up
+construction of copper or brass tubing with cast metal elbows and Y
+pieces. One of the disadvantages advanced against the cast manifold is
+that blowholes may exist which produce imperfect castings and which will
+cause mixture troubles because the entering gas from the carburetor,
+which may be of proper proportions, is diluted by the excess air which
+leaks in through the porous casting. Another factor of some moment is
+that the roughness of the walls has a certain amount of friction which
+tends to reduce the velocity of the gases, and when projecting pieces
+are present, such as core wire or other points of metal, these tend to
+collect the drops of liquid fuel and thus promote condensation. The
+advantage of the built-up construction is that the walls of the tubing
+are very smooth, and as the castings are small it is not difficult to
+clean them out thoroughly before they are incorporated in the manifold.
+The tubing and castings are joined together by hard soldering, brazing
+or autogenous welding.
+
+
+COMPENSATING FOR VARYING ATMOSPHERIC CONDITIONS
+
+The low-grade gasoline used at the present time makes it necessary to
+use vaporizers that are more susceptible to atmospheric variations than
+when higher grade and more volatile liquids are vaporized. Sudden
+temperature changes, sometimes being as much as forty degrees rise or
+fall in twelve hours, affect the mixture proportions to some extent, and
+not only changes in temperature but variations in altitude also have a
+bearing on mixture proportions by affecting both gasoline and air. As
+the temperature falls the specific gravity of the gasoline increases
+and it becomes heavier, this producing difficulty in vaporizing. The
+tendency of very cold air is to condense gasoline instead of vaporizing
+it and therefore it is necessary to supply heated air to some
+carburetors to obtain proper mixtures during cold weather. In order that
+the gas mixtures will ignite properly the fuel must be vaporized and
+thoroughly mixed with the entering air either by heat or high velocity
+of the gases. The application of air stoves to the Curtiss OX-2 motor is
+clearly shown at Fig. 54. It will be seen that flexible metal pipes are
+used to convey the heated air to the air intakes of the duplex mixing
+chamber.
+
+[Illustration: Fig. 56.--Chart Showing Diminution of Air Pressure as
+Altitude Increases.]
+
+
+HOW HIGH ALTITUDE AFFECTS POWER
+
+Any internal combustion engine will show less power at high altitudes
+than it will deliver at sea level, and this has caused a great deal of
+questioning. "There is a good reason for this," says a writer in "Motor
+Age," "and it is a physical impossibility for the engine to do
+otherwise. The difference is due to the lower atmospheric pressure the
+higher up we get. That is, at sea level the atmosphere has a pressure of
+14.7 pounds per square inch; at 5,000 feet above sea level the pressure
+is approximately 12.13 pounds per square inch, and at 10,000 feet it is
+10 pounds per square inch. From this it will be seen that the final
+pressure attained after the piston has driven the gas into compressed
+condition ready for firing is lower as the atmospheric pressure drops.
+This means that there is not so much power in the compressed charge of
+gas the higher up you get above sea level.
+
+"For example, suppose the compression ratio to be 4-1/2 to 1; in other
+words, suppose the air space above the piston to have 4-1/2 times the
+volume when the piston is at the bottom of its stroke that it has when
+the piston is at the top of the stroke. That is a common compression
+ratio for an average motor, and is chosen because it is considered to be
+the best for maximum horse-power and in order that the compression
+pressure will not be so high as to cause pre-ignition. Knowing the
+compression ratio, we can determine the final pressure immediately
+before ignition by substituting in the standard formula:
+
+ P^{1} = P(V/V^{1})^{1.3}
+
+in which P is the atmospheric pressure; P^{1} is the final pressure, and
+V/V^{1} is the compression ratio, therefore P^{1} = 14.7 (4.5)^{1.3} =
+104 pounds per square inch, absolute.
+
+"That is, 104 pounds per square inch is the most efficient final
+compression pressure to have for this engine at sea level, since it
+comes directly from the compression ratio.
+
+"Now supposing we consider that the altitude is 7,000 feet above sea
+level. At this height the atmospheric pressure is 11.25 pounds per
+square inch, approximately. In this case we can again substitute in the
+formula, using the new atmospheric pressure figure. The equation
+becomes:
+
+ P^{1} = 11.25 (4.5)^{1.3}--79.4 pounds per square inch, absolute.
+
+"Therefore we now have a final compression pressure of only 79.4 pounds
+per square inch, which is considerably below the pressure we have just
+found to be the most efficient for the motor. The resulting power drop
+is evident.
+
+"It should be borne in mind that these final compression pressures are
+absolute pressures--that is, they include the atmospheric pressure. In
+the first case, to get the pressure above atmospheric you would subtract
+14.7 and in the latter 11.25 would have to be deducted. In other words,
+where the sea level compression is 89.3 pounds per square inch above the
+atmosphere, the same motor will have only a compression pressure of
+68.15 pounds per square inch above the atmosphere at 7,000 feet
+elevation.
+
+"From the above it is evident that in order to bring the final
+compression pressure up to the efficient figure we have determined, a
+different compression ratio would have to be used. That is, the final
+volume would have to be less, and as it is impossible to vary this to
+meet the conditions of altitude, the loss of power cannot be helped
+except by the replacing of the standard pistons with some that are
+longer above the wrist-pin so as to reduce the space above the pistons
+when on top center. Then if the ratio is thereby raised to some such
+figures as 5 to 1, the engine will again have its proper final pressure,
+but it will still not have as much power as it would have at sea level,
+since the horse-power varies directly with the atmospheric pressure,
+final compression being kept constant. That is, at 7,000 feet the
+horse-power of an engine that had 40 horse-power at sea level would be
+equal to
+
+ 11.25
+ ------- = 30.6 horse-power.
+ 14.7
+
+"If the original compression ratio of 4.5 were retained, the drop in
+horse-power would be even greater than this. These computations and
+remarks will make it clear that the designer who contemplates building
+an airplane for high altitude use should see to it that it is of
+sufficient power to compensate for the drop that is inevitable when it
+is up in the air. This is often illustrated in stationary gas-engine
+installations. An engine that had a sea-level rating amply sufficient
+for the work required, might not be powerful enough when brought up
+several thousand feet." When one considers that airplanes attain heights
+of over 18,000 feet, it will be evident that an ample margin of engine
+power is necessary.
+
+
+THE DIESEL SYSTEM
+
+A system of fuel supply developed by the late Dr. Diesel, a German
+chemist and engineer, is attracting considerable attention at the
+present time on account of the ability of the Diesel engine to burn
+low-grade fuels, such as crude petroleum. In this system the engines are
+built so that very high compressions are used, and only pure air is
+taken into the cylinder on the induction stroke. This is compressed to a
+pressure of about 500 pounds per square inch, and sufficient heat is
+produced by this compression to explode a hydrocarbon mixture. As the
+air which is compressed to this high point cannot burn, the fuel is
+introduced into the cylinder combustion chamber under still higher
+compression than that of the compressed air, and as it is injected in a
+fine stream it is immediately vaporized because of the heat. Just as
+soon as the compressed air becomes thoroughly saturated with the liquid
+fuel, it will explode on account of the degree of heat present in the
+combustion chamber. Such motors have been used in marine and stationary
+applications, but are not practical for airplanes or motor cars because
+of lack of flexibility and great weight in proportion to power
+developed. The Diesel engine is the standard power plant used in
+submarine boats and motor ships, as its efficiency renders it
+particularly well adapted for large units.
+
+
+NOTES ON CARBURETOR INSTALLATION IN AIRPLANES
+
+A writer in "The Aeroplane," an English publication, discourses on some
+features of carburetor installation that may be of interest to the
+aviation student, so portions of the dissertation are reproduced
+herewith.
+
+ "Users of airplanes fitted with ordinary type carburetors will
+ do well to note carefully the way in which these are fitted, for
+ several costly machines have been burnt lately through the sheer
+ carelessness of their users. These particular machines were
+ fitted with a high powered V-type engine, made by a firm which
+ is famous as manufacturers of automobiles _de luxe_. In these
+ engines there are four carburetors, mounted in the V between the
+ cylinders. When the engine is fitted as a tractor, the float
+ chambers are in front of the jet chambers. Consequently, when
+ the tail of the machine is resting on the ground, the jets are
+ lower than the level of the gasoline in the float chamber.
+
+ "Quite naturally, the gasoline runs out of the jet, if it is
+ left turned on when the machine is standing in its normal
+ position, and trickles into the V at the top of the crank-case.
+ Thence it runs down to the tail of the engine, where the
+ magnetos are fitted, and saturates them. If left long enough,
+ the gasoline manages to soak well into the fuselage before
+ evaporating. And what does evaporate makes an inflammable gas in
+ the forward cockpit. Then some one comes along and starts up the
+ engine. The spark-gap of the magneto gives one flash, and the
+ whole front of the machine proceeds to give a Fourth of July
+ performance forthwith. Naturally, one safeguard is to turn the
+ petrol off directly the machine lands. Another is never to turn
+ it on till the engine is actually being started up.
+
+ "One would be asking too much of the human boy--who is
+ officially regarded as the only person fit to fly an
+ aeroplane--if one depended upon his memory of such a detail to
+ save his machine, though one might perhaps reasonably expect the
+ older pilots to remember not to forget. Even so, other means of
+ prevention are preferable, for fire is quite as likely to occur
+ from just the same cause if the engine happens to be a trifle
+ obstinate in starting, and so gives the carburetors several
+ minutes in which to drip--in which operation they would probably
+ be assisted by air-mechanics 'tickling' them.
+
+ "One way out of the trouble is to fit drip tins under the jet
+ chamber to catch the gasoline as it falls. This is all very well
+ just to prevent fire while the machine is being started up, but
+ it will not save it if it is left standing with the tail on the
+ ground and the petrol turned on, for the drip tins will then
+ fill up and run over. And if it catches then, the contents of
+ the drip tins merely add fuel to the fire.
+
+
+ _Reversing Carburetors_
+
+ "Yet another way is to turn the carburetors round, so that the
+ float chambers are behind the jets, and so come below them when
+ the tail is on the ground, thus cutting off the gasoline low
+ down in the jets. There seems to be no particular mechanical
+ difficulty about this, though I must confess that I did not note
+ very carefully whether the reversal of the float chambers would
+ make them foul any other fittings on the engine. It has been
+ argued, however, that doing this would starve the engine of
+ gasoline when climbing at a steep angle, as the gasoline would
+ then be lowered in the jets and need more suction to get into
+ the cylinders. This is rather a pretty point of amateur motor
+ mechanics to discuss, for, obviously, when the same engine is
+ used as a 'pusher' instead of a tractor, the jets are in front
+ of the floats, and there seems to be no falling off in power.
+
+
+ _Starvation of Mixture_
+
+ "Moreover, the higher a machine goes the lower is the
+ atmospheric pressure, and, consequently, the less is the amount
+ of air sucked in at each induction stroke. This means, of
+ course, that with the gasoline supply the mixture at high
+ altitudes is too rich, so that, in order to get precisely the
+ right mixture when very high up, it is necessary to reduce the
+ gasoline supply by screwing down the needle valve between the
+ tank and the carburetor--at least, that has been the experience
+ of various high-flying pilots. No doubt something might be done
+ in the way of forced air feed to compensate for reduced
+ atmospheric pressure, but it remains to be proved whether the
+ extra weight of mechanism involved would pay for the extra power
+ obtained. Variable compression might do something, also, to even
+ things up, but here, also, weight of mechanism has to be
+ considered.
+
+ "In any case, at present, the higher one goes the more the
+ power of the engine is reduced, for less air means a less volume
+ of mixture per cylinder, and as the petrol feed has to be
+ starved to suit the smaller amount of air available, this means
+ further loss of power. I do not know whether anyone has evolved
+ a carburetor which automatically starves the gasoline feed when
+ high up, but it seems possible that when an airplane is sagging
+ about 'up against the ceiling'--as a French pilot described the
+ absolute limit of climb for his particular machine--it might be
+ a good thing to have the jets in front of the float chamber, for
+ then a certain amount of automatic starvation would take place.
+
+ "When a machine is right up at its limiting height, and the
+ pilot is doing his best to make it go higher still, it is
+ probably flying with its tail as low as the pilot dares to let
+ it go, and the lateral and longitudinal controls are on the
+ verge of vanishing, so that if the carburetor jets are behind
+ the float chambers there is bound to be an over-rich mixture in
+ any case. There is even a possibility of a careless or ignorant
+ pilot carrying on in this tail-down position till one set of
+ cylinders cuts out altogether, in which case the carburetor
+ feeding that set may flood over, just as if the machine were on
+ the ground, and the whole thing may catch fire. Whereas, with
+ the jets in front of the floats, though the mixture may starve a
+ trifle, there is, at any rate, no danger of fire through
+ climbing with the tail down.
+
+
+ _A Diving Danger_
+
+ "On the other hand, in a 'pusher' with this type of engine, if
+ the jets are in their normal position--which is in front of the
+ floats--there is danger of fire in a dive. That is to say, if
+ the pilot throttles right down, or switches off and relies on
+ air pressure on his propeller to start the engine again, so that
+ the gasoline is flooding over out of the jets instead of being
+ sucked into the engine, there may be flooding over the magnetos
+ if the dive is very steep and prolonged. In any case, a long
+ dive will mean a certain amount of flooding, and, probably, a
+ good deal of choking and spitting by the engine before it gets
+ rid of the over-rich mixture and picks up steady firing again.
+ Which may indicate to young pilots that it is not good to come
+ down too low under such circumstances, trusting entirely to
+ their engines to pick up at once and get going before they hit
+ the ground.
+
+ "On the whole, it seems that it might be better practice to set
+ the carburetors thwartwise of engines, for then jets and floats
+ would always be at approximately the same level, no matter what
+ the longitudinal position of the machine, and it is never long
+ enough in one position at a big lateral angle to raise any
+ serious carburetor troubles. Car manufacturers who dive
+ cheerfully into the troubled waters of aero-engine designs are
+ a trifle apt to forget that their engines are put into positions
+ on airplanes which would be positively indecent in a motor car.
+ An angle of 1 in 10 is the exception on a car, but it is common
+ on an airplane, and no one ever heard of a car going down a hill
+ of 10 to 1--which is not quite a vertical dive. Therefore, there
+ is every excuse for a well-designed and properly brought-up
+ carburetor misbehaving itself in an aeroplane.
+
+ "It seems, then, that it is up to the manufacturers to produce
+ better carburetors--say, with the jet central with the float.
+ But it also behooves the user to show ordinary common sense in
+ handling the material at present available, and not to make a
+ practice of burning up $25,000 worth or so of airplane just
+ because he is too lazy to turn off his gasoline, or to have the
+ tail of his machine lifted up while he is tinkering with his
+ engines."
+
+
+NOTES ON CARBURETOR ADJUSTMENT
+
+The modern float feed carburetor is a delicate and nicely balanced
+appliance that requires a certain amount of attention and care in order
+to obtain the best results. The adjustments can only be made by one
+possessing an intelligent knowledge of carburetor construction and must
+never be made unless the reason for changing the old adjustment is
+understood. Before altering the adjustment of the leading forms of
+carburetors, a few hints regarding the quality to be obtained in the
+mixture should be given some consideration, as if these are properly
+understood this knowledge will prove of great assistance in adjusting
+the vaporizer to give a good working proportion of fuel and air. There
+is some question regarding the best mixture proportions and it is
+estimated that gas will be explosive in which the proportions of fuel
+vapor and air will vary from one part of the former to a wide range
+included between four and eighteen parts of the latter. A one to four
+mixture is much too rich, while the one in eighteen is much too lean to
+provide positive ignition.
+
+A rich mixture should be avoided because the excessive fuel used will
+deposit carbon and will soot the cylinder walls, combustion chamber
+interior, piston top and valves and also tend to overheat the motor. A
+rich mixture will also seriously interfere with flexible control of the
+engine, as it will choke up on low throttle and run well on open
+throttle when the full amount of gas is needed. A rich mixture may be
+quickly discovered by black smoke issuing from the muffler, the exhaust
+gas having a very pungent odor. If the mixture contains a surplus of air
+there will be popping sounds in the carburetor, which is commonly termed
+"blowing back." To adjust a carburetor is not a difficult matter when
+the purpose of the various control members is understood. The first
+thing to do in adjusting a carburetor is to start the motor and to
+retard the sparking lever so the motor will run slowly leaving the
+throttle about half open. In order to ascertain if the mixture is too
+rich cut down the gasoline flow gradually by screwing down the needle
+valve until the motor commences to run irregularly or misfire. Close the
+needle valves as far as possible without having the engine come to a
+stop, and after having found the minimum amount of fuel gradually
+unscrew the adjusting valve until you arrive at the point where the
+engine develops its highest speed. When this adjustment is secured the
+lock nut is screwed in place so the needle valve will keep the
+adjustment. The next point to look out for is regulation of the
+auxiliary air supply on those types of carburetors where an adjustable
+air valve is provided. This is done by advancing the spark lever and
+opening the throttle. The air valve is first opened or the spring
+tension reduced to a point where the engine misfires or pops back in the
+carburetor. When the point of maximum air supply the engine will run on
+is thus determined, the air valve spring may be tightened by screwing in
+on the regulating screw until the point is reached where an appreciable
+speeding up of the engine is noticed. If both fuel and air valves are
+set right, it will be possible to accelerate the engine speed uniformly
+without interfering with regularity of engine operation by moving the
+throttle lever or accelerator pedal from its closed to its wide open
+position, this being done with the spark lever advanced. All types of
+carburetors do not have the same means of adjustment; in fact, some
+adjust only with the gasoline regulating needle; others must have a
+complete change of spray nozzles; while in others the mixture
+proportions may be varied only by adjustment of the quantity of entering
+air. Changing the float level is effective in some carburetors, but this
+should never be done unless it is certain that the level is not correct.
+Full instructions for locating carburetion troubles will be given in
+proper sequence.
+
+It is a fact well known to experienced repairmen and motorists that
+atmospheric conditions have much to do with carburetor action. It is
+often observed that a motor seems to develop more power at night than
+during the day, a circumstance which is attributed to the presence of
+more moisture in the cooler night air. Likewise, taking a motor from sea
+level to an altitude of 10,000 feet involves using rarefied air in the
+engine cylinders and atmospheric pressures ranging from 14.7 pounds at
+sea level to 10.1 pounds per square inch at the high altitude. All
+carburetors will require some adjustment in the course of any material
+change from one level to another. Great changes of altitude also have a
+marked effect on the cooling system of an airplane. Water boils at 212
+degrees F. only at sea level. At an altitude of 10,000 feet it will boil
+at a temperature nineteen degrees lower, or 193 degrees F.
+
+In high altitudes the reduced atmospheric pressure, for 5,000 feet or
+higher than sea level, results in not enough air reaching the mixture,
+so that either the auxiliary air opening has to be increased, or the
+gasoline in the mixture cut down. If the user is to be continually at
+high altitudes he should immediately purchase either a larger dome or a
+smaller strangling tube, mentioning the size carburetor that is at
+present in use and the type of motor that it is on, including details as
+to the bore and stroke. The smaller strangling tube makes an increased
+suction at the spray nozzle; the air will have to be readjusted to meet
+it and you can use more auxiliary air, which is necessary. The effect
+on the motor without a smaller strangling tube is a perceptible
+sluggishness and failure to speed up to its normal crank-shaft
+revolutions, as well as failure to give power. It means that about
+one-third of the regular speed is cut out. The reduced atmospheric
+pressure reduces the power of the explosion, in that there is not the
+same quantity of oxygen in the combustion chamber as at sea level; to
+increase the amount taken in, you must also increase the gasoline speed,
+which is done by an increased suction through the smaller strangling
+aperture. Some forms of carburetors are affected more than others by
+changes of altitude, which explains why the Zenith is so widely employed
+for airplane engine use. The compensating nozzle construction is not
+influenced as much by changes of altitude as the simpler nozzle types
+are.
+
+
+
+
+CHAPTER VI
+
+ Early Ignition Systems--Electrical Ignition Best--Fundamentals
+ of Magnetism Outlined--Forms of Magneto--Zones of Magnetic
+ Influence--How Magnets are Made--Electricity and Magnetism
+ Related--Basic Principles of Magneto Action--Essential Parts of
+ Magneto and Functions--Transformer Coil Systems--True High
+ Tension Type--The Berling Magneto--Timing and Care--The Dixie
+ Magneto--Spark Plug Design and Application--Two-Spark Ignition--
+ Special Airplane Plug.
+
+
+EARLY IGNITION SYSTEMS
+
+One of the most important auxiliary groups of the gasoline engine
+comprising the airplane power plant and one absolutely necessary to
+insure engine action is the ignition system or the method employed of
+kindling the compressed gas in the cylinder to produce an explosion and
+useful power. The ignition system has been fully as well developed as
+other parts of the engine, and at the present time practically all
+ignition systems follow principles which have become standard through
+wide acceptance.
+
+During the early stages of development of the gasoline engine various
+methods of exploding the charge of combustible gas in the cylinder were
+employed. On some of the earliest engines a flame burned close to the
+cylinder head, and at the proper time for ignition a slide or valve
+moved to provide an opening which permitted the flame to ignite the gas
+back of the piston. This system was practical only on the primitive form
+of gas engines in which the charge was not compressed before ignition.
+Later, when it was found desirable to compress the gas a certain degree
+before exploding it, an incandescent platinum tube in the combustion
+chamber, which was kept in a heated condition by a flame burning in it,
+exploded the gas. The naked flame was not suitable in this application
+because when the slide was opened to provide communication between the
+flame and the gas the compressed charge escaped from the cylinder with
+enough pressure to blow out the flame at times and thus cause irregular
+ignition. When the flame was housed in a platinum tube it was protected
+from the direct action of the gas, and as long as the tube was
+maintained at the proper point of incandescence regular ignition was
+obtained.
+
+Some engineers utilized the property of gases firing themselves if
+compressed to a sufficient degree, while others depended upon the heat
+stored in the cylinder-head to fire the highly compressed gas. None of
+these methods were practical in their application to motor car engines
+because they did not permit flexible engine action which is so
+desirable. At the present time, electrical ignition systems in which the
+compressed gas is exploded by the heating value of the minute electric
+arc or spark in the cylinder are standard, and the general practice
+seems to be toward the use of mechanical producers of electricity rather
+than chemical batteries.
+
+
+ELECTRICAL IGNITION BEST
+
+Two general forms of electrical ignition systems may be used, the most
+popular being that in which a current of electricity under high tension
+is made to leap a gap or air space between the points of the sparking
+plug screwed into the cylinder. The other form, which has been almost
+entirely abandoned in automobile and which was never used with airplane
+engine practice, but which is still used to some extent on marine
+engines, is called the low-tension system because current of low voltage
+is used and the spark is produced by moving electrodes in the combustion
+chamber.
+
+The essential elements of any electrical ignition system, either high or
+low tension, are: First, a simple and practical method of current
+production; second, suitable timing apparatus to cause the spark to
+occur at the right point in the cycle of engine action; third, suitable
+wiring and other apparatus to convey the current produced by the
+generator to the sparking member in the cylinder.
+
+The various appliances necessary to secure prompt ignition of the
+compressed gases should be described in some detail because of the
+importance of the ignition system. It is patent that the scope of a work
+of this character does not permit one to go fully into the theory and
+principles of operation of all appliances which may be used in
+connection with gasoline motor ignition, but at the same time it is
+important that the elementary principles be considered to some extent in
+order that the reader should have a proper understanding of the very
+essential ignition apparatus. The first point considered will be the
+common methods of generating the electricity, then the appliances to
+utilize it and produce the required spark in the cylinder. Inasmuch as
+magneto ignition is universally used in connection with airplane engine
+ignition it will not be necessary to consider battery ignition systems.
+
+
+FUNDAMENTALS OF MAGNETISM OUTLINED
+
+To properly understand the phenomena and forces involved in the
+generation of electrical energy by mechanical means it is necessary to
+become familiar with some of the elementary principles of magnetism and
+its relation to electricity. The following matter can be read with
+profit by those who are not familiar with the subject. Most persons know
+that magnetism exists in certain substances, but many are not able to
+grasp the terms used in describing the operation of various electrical
+devices because of not possessing a knowledge of the basic facts upon
+which the action of such apparatus is based.
+
+Magnetism is a property possessed by certain substances and is
+manifested by the ability to attract and repel other materials
+susceptible to its effects. When this phenomenon is manifested by a
+conductor or wire through which a current of electricity is flowing it
+is termed "electro-magnetism." Magnetism and electricity are closely
+related, each being capable of producing the other. Practically all of
+the phenomena manifested by materials which possess magnetic qualities
+naturally can be easily reproduced by passing a current of electricity
+through a body which, when not under electrical influence, is not a
+magnetic substance. Only certain substances show magnetic properties,
+these being iron, nickel, cobalt and their alloys.
+
+The earliest known substance possessing magnetic properties was a stone
+first found in Asia Minor. It was called the lodestone or leading stone,
+because of its tendency, if arranged so it could be moved freely, of
+pointing one particular portion toward the north. The compass of the
+ancient Chinese mariners was a piece of this material, now known to be
+iron ore, suspended by a light thread or floated on a cork in some
+liquid so one end would point toward the north magnetic pole of the
+earth. The reason that this stone was magnetic was hard to define for a
+time, until it was learned that the earth was one huge magnet and that
+the iron ore, being particularly susceptible, absorbed and retained some
+of this magnetism.
+
+Most of us are familiar with some of the properties of the magnet
+because of the extensive sale and use of small horseshoe magnets as
+toys. As they only cost a few pennies every one has owned one at some
+time or other and has experimented with various materials to see if they
+would be attracted. Small pieces of iron or steel were quickly attracted
+to the magnet and adhered to the pole pieces when brought within the
+zone of magnetic influence. It was soon learned that brass, copper, tin
+or zinc were not affected by the magnet. A simple experiment that serves
+to illustrate magnetic attraction of several substances is shown at A,
+Fig. 57. In this, several balls are hung from a standard or support, one
+of these being of iron, another of steel. When a magnet is brought near
+either of these they will be attracted toward it, while the others will
+remain indifferent to the magnetic force. Experimenters soon learned
+that of the common metals only iron or steel were magnetic.
+
+[Illustration: Fig. 57.--Some Simple Experiments to Demonstrate Various
+Magnetic Phenomena and Clearly Outline Effects of Magnetism and Various
+Forms of Magnets.]
+
+If the ordinary bar or horseshoe magnet be carefully examined, one end
+will be found to be marked N. This indicates the north pole, while the
+other end is not usually marked and is the south pole. If the north pole
+of one magnet is brought near the south pole of another, a strong
+attraction will exist between them, this depending upon the size of the
+magnets used and the air gap separating the poles. If the south pole of
+one magnet is brought close to the end of the same polarity of the other
+there will be a pronounced repulsion of like force. These facts are
+easily proved by the simple experiment outlined at B, Fig. 57. A magnet
+will only attract or influence a substance having similar qualities. The
+like poles of magnets will repel each other because of the obvious
+impossibility of uniting two influences or forces of practically equal
+strength but flowing in opposite directions. The unlike poles of magnets
+attract each other because the force is flowing in the same direction.
+The flow of magnetism is through the magnet from south to north and the
+circuit is completed by the flow of magnetic influence through the air
+gap or metal armature bridging it from the north to the south pole.
+
+
+FORMS OF MAGNETS AND ZONE OF MAGNETIC INFLUENCE DEFINED
+
+Magnets are commonly made in two forms, either in the shape of a bar or
+horseshoe. These two forms are made in two types, simple or compound.
+The latter are composed of a number of magnets of the same form united
+so the ends of like polarity are laced together, and such a construction
+will be more efficient and have more strength than a simple magnet of
+the same weight. The two common forms of simple and compound magnets are
+shown at C, Fig. 57. The zone in which a magnetic influence occurs is
+called the magnetic field, and this force can be graphically shown by
+means of imaginary lines, which are termed "lines of force." As will be
+seen from the diagram at D, Fig. 57, the lines show the direction of
+action of the magnetic force and also show its strength, as they are
+closer together and more numerous when the intensity of the magnetic
+field is at its maximum. A simple method of demonstrating the presence
+of the force is to lay a piece of thin paper over the pole pieces of
+either a bar or horseshoe magnet and sprinkle fine iron filings on it.
+The particles of metal arrange themselves in very much the manner shown
+in the illustrations and prove that the magnetic field actually exists.
+
+The form of magnet used will materially affect the size and area of the
+magnetic field. It will be noted that the field will be concentrated to
+a greater extent with the horseshoe form because of the proximity of the
+poles. It should be understood that these lines have no actual
+existence, but are imaginary and assumed to exist only to show the way
+the magnetic field is distributed. The magnetic influence is always
+greater at the poles than at the center, and that is why a horseshoe or
+U-form magnet is used in practically all magnetos or dynamos. This
+greater attraction at the poles can be clearly demonstrated by
+sprinkling iron filings on bar and U magnets, as outlined at E, Fig. 57.
+A large mass gathers at the pole pieces, gradually tapering down toward
+the point where the attraction is least.
+
+From the diagrams it will be seen that the flow of magnetism is from one
+pole to the other by means of curved paths between them. This circuit is
+completed by the magnetism flowing from one pole to the other through
+the magnet, and as this flow is continued as long as the body remains
+magnetic it constitutes a magnetic circuit. If this flow were
+temporarily interrupted by means of a conductor of electricity moving
+through the field there would be a current of electricity induced in the
+conductor every time it cut the lines of force. There are three kinds of
+magnetic circuits. A non-magnetic circuit is one in which the magnetic
+influence completes its circuit through some substance not susceptible
+to the force. A closed magnetic circuit is one in which the influence
+completes its circuit through some magnetic material which bridges the
+gap between the poles. A compound circuit is that in which the magnetic
+influence passes through magnetic substances and non-magnetic substances
+in order to complete its circuit.
+
+
+HOW IRON AND STEEL BARS ARE MADE MAGNETIC
+
+Magnetism may be produced in two ways, by contact or induction. If a
+piece of steel is rubbed on a magnet it will be found a magnet when
+removed, having a north and south pole and all of the properties found
+in the energizing magnet. This is magnetizing by contact. A piece of
+steel will retain the magnetism imparted to it for a considerable length
+of time, and the influence that remains is known as residual magnetism.
+This property may be increased by alloying the steel with tungsten and
+hardening it before it is magnetized. Any material that will retain its
+magnetic influence after removal from the source of magnetism is known
+as a permanent magnet. If a piece of iron or steel is brought into the
+magnetic field of a powerful magnet it becomes a magnet without actual
+contact with the energizer. This is magnetizing by magnetic induction.
+If a powerful electric current flows through an insulated conductor
+wound around a piece of iron or steel it will make a magnet of it. This
+is magnetizing by electro-magnetic induction. A magnet made in this
+manner is termed an electro-magnet and usually the metal is of such a
+nature that it will not retain its magnetism when the current ceases to
+flow around it. Steel is used in all cases where permanent magnets are
+required, while soft iron is employed in all cases where an intermittent
+magnetic action is desired. Magneto field magnets are always made of
+tungsten steel alloy, so treated that it will retain its magnetism for
+lengthy periods.
+
+
+ELECTRICITY AND MAGNETISM CLOSELY RELATED
+
+There are many points in which magnetism and electricity are alike. For
+instance, air is a medium that offers considerable resistance to the
+passage of both magnetic influence and electric energy, although it
+offers more resistance to the passage of the latter. Minerals like iron
+or steel are very easily influenced by magnetism and easily penetrated
+by it. When one of these is present in the magnetic circuit the
+magnetism will flow through the metal. Any metal is a good conductor for
+the passage of the electric current, but few metals are good conductors
+of magnetic energy. A body of the proper metal will become a magnet due
+to induction if placed in the magnetic field, having a south pole where
+the lines of force enter it and a north pole where they pass out.
+
+We have seen that a magnet is constantly surrounded by a magnetic field
+and that an electrical conductor when carrying a current is also
+surrounded by a field of magnetic influence. Now if the conductor
+carrying a current of electricity will induce magnetism in a bar of iron
+or steel, by a reversal of this process, a magnetized iron or steel bar
+will produce a current of electricity in a conductor. It is upon this
+principle that the modern dynamo or magneto is constructed. If an
+electro-motive force is induced in a conductor by moving it across a
+field of magnetic influence, or by passing a magnetic field near a
+conductor, electricity is said to be generated by magneto-electric
+induction. All mechanical generators of the electric current using
+permanent steel magnets to produce a field of magnetic influence are of
+this type.
+
+
+BASIC PRINCIPLES OF MAGNETO OUTLINED
+
+The accompanying diagram, Fig. 58, will show these principles very
+clearly. As stated on an earlier page, if the lines of force in the
+magnetic field are cut by a suitable conductor an electrical impulse
+will be produced in that conductor. In this simple machine the lines of
+force exist between the poles of a horseshoe magnet. The conductor,
+which in this case is a loop of copper wire, is mounted upon a spindle
+in order that it may be rotated in the magnetic field to cut the lines
+of magnetic influence present between the pole pieces. Both of the ends
+of this loop are connected, one with the insulated drum shown upon the
+shaft, the other to the shaft. Two metal brushes are employed to collect
+the current and cause it to flow through the external circuit. It can
+be seen that when the shaft is turned in the direction of the arrow the
+loop will cut through the lines of magnetic influence and a current will
+be generated therein.
+
+[Illustration: Fig. 58.--Elementary Form of Magneto Showing Principal
+Parts Simplified to Make Method of Current Generation Clear.]
+
+The pressure of the current and the amount produced vary in accordance
+to the rapidity with which the lines of magnetic influence are cut. The
+armature of a practical magneto, therefore, differs materially from that
+shown in the diagram. A large number of loops of wire would be mounted
+upon this shaft in order that the lines of magnetic influence would be
+cut a greater number of times in a given period and a core of iron used
+as a backing for the wire. This would give a more rapid alternating
+current and a higher electro-motive force than would be the case with a
+smaller number of loops of wire.
+
+[Illustration: Fig. 59.--Showing How Strength of Magnetic Influence and
+of the Currents Induced in the Windings of Armature Vary with the
+Rapidity of Changes of Flow.]
+
+The illustrations at Fig. 59 show a conventional double winding
+armature and field magnetic of a practical magneto in part section and
+will serve to more fully emphasize the points previously made. If the
+armature or spindle were removed from between the pole pieces there
+would exist a field of magnetic influence as shown at Fig. 57, but the
+introduction of this component provides a conductor (the iron core) for
+the magnetic energy, regardless of its position, though the facility
+with which the influence will be transmitted depends entirely upon the
+position of the core. As shown at A, the magnetic flow is through the
+main body in a straight line, while at B, which position the armature
+has attained after one-eighth revolution, or 45 degrees travel in the
+direction of the arrow, the magnetism must pass through in the manner
+indicated. At C, which position is attained every half revolution, the
+magnetic energy abandons the longer path through the body of the core
+for the shorter passage offered by the side pieces, and the field thrown
+out by the cross bar disappears. On further rotation of the armature, as
+at D, the body of the core again becomes energized as the magnetic
+influence resumes its flow through it. These changes in the strength of
+the magnetic field when distorted by the armature core, as well as the
+intensity of the energy existing in the field, affect the windings, and
+the electrical energy induced therein corresponds in strength to the
+rapidity with which these changes in magnetic flow occur. The most
+pronounced changes in the strength of the field will occur as the
+armature passes from position B to D, because the magnetic field
+existing around the core will be destroyed and again re-established.
+
+During the most of the armature rotation the changes in strength will be
+slight and the currents induced in the wire correspondingly small; but
+at the instant the core becomes remagnetized, as the armature leaves
+position C, the current produced will be at its maximum, and it is
+necessary to so time the rotation of the armature that at this instant
+one of the cylinders is in condition to be fired. It is imperative that
+the armature be driven in such relation to the crank-shaft that each
+production of maximum current coincides with the ignition point, this
+condition existing twice during each revolution of the armature, or at
+every 180 degrees travel. Each position shown corresponds to 45 degrees
+travel of the armature, or one-eighth of a turn, and it takes just
+three-eighths revolution to change the position from A to that shown at
+D.
+
+
+ESSENTIAL PARTS OF A MAGNETO AND THEIR FUNCTIONS
+
+The magnets which produce the influence that in turn induces the
+electrical energy in the winding or loops of wire on the armature, and
+which may have any even number of opposed poles, are called field
+magnets. The loops of wire which are mounted upon a suitable drum and
+rotate in the field of magnetic influence in order to cut the lines of
+force is called an armature winding, while the core is the metal
+portion. The entire assembly is called the armature. The exposed ends of
+the magnets are called pole pieces and the arrangement used to collect
+the current is either a commutator or a collector. The stationary pieces
+which bear against the collector or commutator and act as terminals for
+the outside circuit are called brushes. These brushes are often of
+copper, or some of its alloys, because copper has a greater electrical
+conductivity than any other metal.
+
+These brushes are nearly always of carbon, which is sometimes
+electroplated with copper to increase its electrical conductivity,
+though cylinders of copper wire gauze impregnated with graphite are
+utilized at times. Carbon is used because it is not so liable to cut the
+metal of the commutator as might be the case if the contact was of the
+metal to metal type. The reason for this is that carbon has the peculiar
+property in that it materially assists in the lubrication of the
+commutator, and being of soft, unctuous composition, will wear and
+conform to any irregularities on the surface of the metal collector
+rings.
+
+The magneto in common use consists of a number of horseshoe magnets
+which are compound in form and attached to suitable cast-iron pole
+pieces used to collect and concentrate the magnetic influence of the
+various magnets. Between these pole pieces an armature rotates. This is
+usually shaped like a shuttle, around which are wound coils of insulated
+wire. These are composed of a large number of turns and the current
+produced depends in great measure upon the size of the wire and the
+number of turns per coil. An armature winding of large wire will deliver
+a current of great amperage, but of small voltage. An armature wound
+with very fine wire will deliver a current of high voltage but of low
+amperage. In the ordinary form of magneto, such as used for ignition,
+the current is alternating in character and the break in the circuit
+should be timed to occur when the armature is at the point of its
+greatest potential or pressure. Where such a generator is designed for
+direct current production the ends of the winding are attached to the
+segments of a commutator, but where the instrument is designed to
+deliver an alternating current one end of the winding is fastened to an
+insulator ring on one end of the armature shaft and the other end is
+grounded on the frame of the machine.
+
+The quantity of the current depends upon the strength of the magnetic
+field and the number of lines of magnetic influence acting through the
+armature. The electro-motive force varies as to the length of the
+armature winding and the number of revolutions at which the armature is
+rotated.
+
+
+THE TRANSFORMER SYSTEM USES LOW VOLTAGE MAGNETO
+
+The magneto in the various systems which employ a transformer coil is
+very similar to a low-tension generator in general construction, and the
+current delivered at the terminals seldom exceeds 100 volts. As it
+requires many times that potential or pressure to leap the gap which
+exists between the points of the conventional spark plug, a separate
+coil is placed in circuit to intensify the current to one of greater
+capacity. The essential parts of such a system and their relation to
+each other are shown in diagrammatic form at Fig. 60 and as a complete
+system at Fig. 61. As is true of other systems the magnetic influence is
+produced by permanent steel magnets clamped to the cast-iron pole pieces
+between which the armature rotates. At the point of greatest potential
+in the armature winding the current is broken by the contact breaker,
+which is actuated by a cam, and a current of higher value is induced in
+the secondary winding of the transformer coil when the low voltage
+current is passed through the primary winding.
+
+[Illustration: Fig. 60.--Diagrams Explaining Action of Low Tension
+Transformer Coil and True High Tension Magneto Ignition Systems.]
+
+[Illustration: Fig. 60A.--Side Sectional View of Bosch High-Tension
+Magneto Shows Disposition of Parts. End Elevation Depicts Arrangement of
+Interruptor and Distributor Mechanism.]
+
+It will be noted that the points of the contact breaker are together
+except for the brief instant when separated by the action of the point
+of the cam upon the lever. It is obvious that the armature winding is
+short-circuited upon itself except when the contact points are
+separated. While the armature winding is thus short-circuited there will
+be practically no generation of current. When the points are separated
+there is a sudden flow of current through the primary winding of the
+transformer coil, inducing a secondary current in the other winding,
+which can be varied in strength by certain considerations in the
+preliminary design of the apparatus. This current of higher potential or
+voltage is conducted directly to the plug if the device is fitted to a
+single-cylinder engine, or to the distributor arm if fitted to a
+multiple-cylinder motor. The distributor consists of an insulator in
+which is placed a number of segments, one for each cylinder to be fired,
+and so spaced that the number of degrees between them correspond to the
+ignition points of the motor. A two-cylinder motor would have two
+segments, a three-cylinder, three segments, and so on within the
+capacity of the instrument. In the illustration a four-cylinder
+distributor is fitted, and the distributing arm is in contact with the
+segment corresponding to the cylinder about to be fired.
+
+[Illustration: Fig. 61.--Berling Two-Spark Dual Ignition System.]
+
+
+TRUE HIGH-TENSION MAGNETOS ARE SELF-CONTAINED
+
+[Illustration: Fig. 62.--Berling Double-Spark Independent System.]
+
+The true high-tension magneto differs from the preceding inasmuch as the
+current of high voltage is produced in the armature winding direct,
+without the use of the separate coil. Instead of but one coil, the
+armature carries two, one of comparatively coarse wire, the other of
+many turns of finer wire. The arrangement of these windings can be
+readily ascertained by reference to the diagram B, Fig. 60, which shows
+the principle of operation very clearly. The simplicity of the ignition
+system is evident by inspection of Fig. 62. One end of the primary
+winding (coarse wire) is coupled or grounded to the armature core, and
+the other passes to the insulated part of the interrupter. While in some
+forms the interrupter or contact breaker mechanism does not revolve, the
+desired motion being imparted to the contact lever to separate the
+points of a revolving cam, in this the cam or tripping mechanism is
+stationary and the contact breaker revolves. This arrangement makes it
+possible to conduct the current from the revolving primary coil to the
+interrupter by a direct connection, eliminating the use of brushes,
+which would otherwise be necessary. In other forms of this appliance
+where the winding is stationary, the interrupter may be operated by a
+revolving cam, though, if desired, the used of a brush at this point
+will permit this construction with a revolving winding.
+
+During the revolution of the armature the grounded lever makes and
+breaks contact with the insulated point, short-circuiting the primary
+winding upon itself until the armature reaches the proper position of
+maximum intensity of current production, at which time the circuit is
+broken, as in the former instance. One end of the secondary winding
+(fine wire) is grounded on the live end of the primary, the other end
+being attached to the revolving arm of the distributor mechanism. So
+long as a closed circuit is maintained feeble currents will pass through
+the primary winding, and so long as the contact points are together this
+condition will exist. When the current reaches its maximum value,
+because of the armature being in the best position, the cam operates the
+interrupter and the points are separated, breaking the short circuit
+which has existed in the primary winding.
+
+The secondary circuit has been open while the distributor arm has moved
+from one contact to another and there has been no flow of energy through
+this winding. While the electrical pressure will rise in this, even if
+the distributor arm contacted with one of the segments, there would be
+no spark at the plug until the contact points separated, because the
+current in the secondary winding would not be of sufficient strength.
+When the interrupter operates, however, the maximum primary current will
+be diverted from its short circuit and can flow to the ground only
+through the secondary winding and spark-plug circuit. The high pressure
+now existing in the secondary winding will be greatly increased by the
+sudden flow of primary current, and energy of high enough potential to
+successfully bridge the gap at the plug is thereby produced in the
+winding.
+
+
+THE BERLING MAGNETO
+
+[Illustration: Fig. 63.--Type DD Berling High Tension Magneto.]
+
+The Berling magneto is a true high tension type delivering two impulses
+per revolution, but it is made in a variety of forms, both single and
+double spark. Its principle of action does not differ in essentials from
+the high tension type previously described. This magneto is used on
+Curtiss aviation engines and will deliver sparks in a positive manner
+sufficient to insure ignition of engines up to 200 horse-power and at
+rotative speeds of the magneto armature up to 4,000 r. p. m. which is
+sufficient to take care of an eight-cylinder V engine running up to
+2,000 r. p. m. The magneto is driven at crank-shaft speed on
+four-cylinder engines, at 1-1/2 times crank-shaft speed on six-cylinder
+engines and at twice crank-shaft speed on eight-cylinder V types. The
+types "D" and "DD" BERLING Magnetos are interchangeable with
+corresponding magnetos of other standard makes. The dimensions of the
+four-, six- and eight-cylinder types "D" and "DD" are all the same.
+
+The ideal method of driving the magneto is by means of flexible direct
+connecting coupling to a shaft intended for the purpose of driving the
+magneto. As the magneto must be driven at a high speed, a coupling of
+some flexibility is preferable. The employment of such a coupling will
+facilitate the mounting of the magneto, because a small inaccuracy in
+the lining up of the magneto with the driving shaft will be taken care
+of by the flexible coupling, whereas with a perfectly rigid coupling the
+line-up of the magneto must be absolutely accurate. Another advantage of
+the flexible coupling is that the vibration of the motor will not be as
+fully transmitted to the armature shaft on the magneto as in case a
+rigid coupling is used. This means prolonged life for the magneto.
+
+The next best method of driving the magneto is by means of a gear keyed
+to the armature shaft. When this method of driving is employed, great
+care must be exercised in providing sufficient clearance between the
+gear on the magneto and the driving gear. If there should be a tight
+spot between these two gears it will react disadvantageously on the
+magneto. The third available method is to drive the magneto by means of
+a chain. This is the least desirable of the three methods and should be
+resorted to only in case of absolute necessity. It is difficult to
+provide sufficient clearance when using a chain without rendering the
+timing less accurate and positive.
+
+[Illustration: Fig. 64.--Wiring Diagrams of Berling Magneto Ignition
+Systems.]
+
+Fig. 64, A shows diagrammatically the circuit of the "D" type two-spark
+independent magneto and the switch used with it. In position OFF the
+primary winding of the magneto is short-circuited and in this position
+the switch serves as an ordinary cut-out or grounding switch. In
+position "1" the switch connects the magneto in such a way that it
+operates as an ordinary single-spark magneto. In this position one end
+of the secondary winding is grounded to the body of the motor. This is
+the starting position. In this position of the switch the entire voltage
+generated in the magneto is concentrated at one spark-plug instead of
+being divided in half. With the motor turning over very slowly, as is
+the case in starting, the full voltage generated by the magneto will
+not in all cases be sufficient to bridge simultaneously two spark gaps,
+but is amply sufficient to bridge one. Also, this position of the switch
+tends to retard the ignition and should be used in starting to prevent
+back-firing. With the switch in position "2" the magneto applies
+ignition to both plugs in each cylinder simultaneously. This is the
+normal running position.
+
+Fig. 64, B shows diagrammatically the circuit of the type "DD" BERLING
+high-tension two-spark dual magneto. This type is recommended for
+certain types of heavy-duty airplane motors, which it is impossible to
+turn over fast enough to give the magneto sufficient speed to generate
+even a single spark of volume great enough to ignite the gas in the
+cylinder. The dual feature consists of the addition to the magneto of a
+battery interrupter. The equipment consists of the magneto, coil and
+special high-tension switch. The coil is intended to operate on six
+volts. Either a storage battery or dry cells may be used.
+
+With the switch in the OFF position, the magneto is grounded, and the
+battery circuit is open. With the switch in the second or battery
+position marked "BAT," one end of the secondary winding of the magneto
+is grounded, and the magneto operates as a single-spark magneto
+delivering high-tension current to the inside distributor, and the
+battery circuit being closed the high-tension current from the coil is
+delivered to the outside distributor. In this position the battery
+current is supplied to one set of spark plugs, no matter how slowly the
+motor is turned over, but as soon as the motor starts, the magneto
+supplies current as a single-spark magneto to the other set of the
+spark-plugs. After the engine is running, the switch should be thrown to
+the position marked "MAG." The battery and coil are then disconnected,
+and the magneto furnishes ignition to both plugs in each cylinder. This
+is the normal running position. Either a non-vibrating coil type "N-1"
+is furnished or a combined vibrating and non-vibrating coil type
+"VN-1."
+
+
+SETTING BERLING MAGNETO
+
+The magneto may be set according to one of two different methods, the
+selection of which is, to some extent, governed by the characteristics
+of the engine, but largely due to the personal preference on the part of
+the user. In the first method described below, the most advantageous
+position of the piston for fully advanced ignition is determined in
+relation to the extreme advanced position of the magneto. In this case,
+the fully retarded ignition will not be a matter of selection, but the
+timing range of the magneto is wide enough to bring the fully retarded
+ignition after top-center position of the piston. The second method for
+the setting of the magneto fixes the fully retarded position of the
+magneto in relation to that position of the piston where fully retarded
+ignition is desired. In this case, the extreme advance position of the
+magneto will not always correspond with the best position of the piston
+for fully advanced ignition, and the amount of advance the magneto
+should have to meet ideal requirements in this respect must be
+determined by experiment.
+
+
+_First Method:_
+
+1. Designate one cylinder as cylinder No. 1.
+
+2. Turn the crank-shaft until the piston in cylinder No. 1 is in the
+position where the fully advanced spark is desired to occur.
+
+3. Remove the cover from the distributor block and turn the armature
+shaft in the direction of rotation of the magneto until the distributor
+finger-brush comes into such a position that this brush makes contact
+with the segment which is connected to the cable terminal marked "1."
+This is either one of the two bottom segments, depending upon the
+direction of rotation.
+
+4. Place the cam housing in extreme advance, i.e., turn the cam housing
+until it stops, in the direction opposite to the direction of rotation
+of the armature. With the cam housing in this position, open the cover.
+
+5. With the armature in the approximate position as described in "3,"
+turn the armature slightly in either direction to such a point that the
+platinum points of the magneto interrupter will just begin to open at
+the end of the cam, adjacent to the fibre lever on the interrupter.
+
+6. With this exact position of the armature, fix the magneto to the
+driving member of the engine.
+
+
+_Second Method:_
+
+1. Designate one cylinder as cylinder No. 1.
+
+2. Turn the crank-shaft until the piston in cylinder No. 1 is in the
+position at which the fully retarded spark is desired to occur.
+
+3. Same as No. 3 under First Method.
+
+4. Place the cam housing in extreme retard, i.e., turn the cam housing
+until it stops, in the same direction as the direction of rotation of
+the armature. With the cam housing in this position, open the cover.
+
+5. Same as No. 5 under First Method.
+
+6. Same as No. 6 under First Method.
+
+
+WIRING THE MAGNETO
+
+The wiring of the magneto is clearly shown by wiring diagram.
+
+First determine the sequence of firing for the cylinders and then
+connect the cables to the spark plug in the cylinders in proper
+sequence, beginning with cylinder No. 1 marked on the distributor block.
+
+The switch used with the independent type must be mounted in such a
+manner that there will be a metallic connection between the frame of the
+magneto and the metal portion of the switch.
+
+It is advisable to use a separate battery, either storage or dry cells,
+as a source of current for the dual equipment. Connecting to the same
+battery that is used with the generator and other electrical equipment
+may cause trouble, as a "ground" in this battery causes the coil to
+overheat.
+
+
+CARE AND MAINTENANCE
+
+
+_Lubrication:_
+
+Use only the very best of oil for the oil cups.
+
+Put five drops of oil in the oil cup at the driving end of the magneto
+for every fifty hours of actual running.
+
+Put five drops of oil in the oil cup at the interrupter end of the
+magneto, located at one side of the cam housing, for every hundred hours
+of actual running.
+
+Lubricate the embossed cams in the cam housing with a thin film of
+vaseline every fifty hours of actual running. Wipe off all superfluous
+vaseline. Never use oil in the interrupter. Do not lubricate any other
+part of the interrupter.
+
+
+_Adjusting the Interrupter:_
+
+With the fibre lever in the center of one of the embossed cams, as at
+Fig. 65, the opening between the platinum contacts should be not less
+than .016" and not more than .020". The gauge riveted to the adjusting
+wrench should barely be able to pass between the contacts when fully
+open. The platinum contacts must be smoothed off with a very fine file.
+When in closed position, the platinum contacts should make contact with
+each other over their entire surfaces.
+
+When inspecting the interrupter, make sure that the ground brush in the
+back of the interrupter base is making good contact with the surface on
+which it rubs.
+
+
+_Cleaning the Distributor:_
+
+The distributor block cover should be removed for inspection every
+twenty-five hours of actual running and the carbon deposit from the
+distributor finger-brush wiped off the distributor block by rubbing with
+a rag or piece of waste dipped in gasoline or kerosene. The
+high-tension terminal brush on the side of the magneto should also be
+carefully inspected for proper tension.
+
+
+LOCATING TROUBLE
+
+Trouble in the ignition system is indicated by the motor "missing,"
+stopping entirely, or by inability to start.
+
+It is safe to assume that the trouble is not in the magneto, and the
+carburetor, gasoline supply and spark-plugs should first be
+investigated.
+
+[Illustration: Fig. 65.--The Berling Magneto Breaker Box Showing Contact
+Points Separated and Interruptor Lever on Cam.]
+
+If the magneto is suspected, the first thing to do is to determine if it
+will deliver a spark. To determine this, disconnect one of the
+high-tension leads from the spark-plug in one of the cylinders and place
+it so that there is approximately 1/16" between the terminal and the
+cylinder frame.
+
+Open the pet cocks on the other cylinders to prevent the engine from
+firing and turn over the engine until the piston is approaching the end
+of the compression stroke in the cylinder from which the cable has been
+removed. Set the magneto in the advance position and rapidly rock the
+engine over the top-center position, observing closely if a spark occurs
+between the end of the high-tension cable and the frame.
+
+If the magneto is of the dual type, the trouble may be either in the
+magneto or in the battery or coil system, therefore disconnect the
+battery and place the switch in the position marked "MAG." The magneto
+will then operate as an independent magneto and should spark in the
+proper manner. After this the battery system should be investigated. To
+test the operation of the battery and coil, examine all connections,
+making sure that they are clean and tight, and then with the switch, in
+the "BAT," rock the piston slowly back and forth. If a type "VN-1" coil
+is used, a shower of sparks should jump between the high-tension cable
+terminal and the cylinder frame when the piston is in the correct
+position for firing. If no spark occurs, remove the cover from the coil
+and see that the vibrating tongue is free. If a type "N-1" coil is used,
+a single spark will occur. The battery should furnish six volts when
+connected to the coil, and this should also be verified.
+
+If the coil still refuses to give a spark and all connections are
+correct, the coil should be replaced and the defective coil returned to
+the manufacturer.
+
+If both magneto and coil give a spark when tested as just described, the
+spark-plugs should be investigated. To do this, disconnect the cables
+and remove the spark-plugs. Then reconnect the cables to the plugs and
+place them so that the frame portions of the plugs are in metallic
+connection with the frame of the motor. Then turn over the motor, thus
+revolving the magneto armature, and see if a spark is produced at the
+spark gaps of the plugs.
+
+The most common defects in spark-plugs are breaking down of the
+insulation, fouling due to carbon, or too large or small a spark gap. To
+clean the plugs a stiff brush and gasoline should be used. The spark
+gap should be about 1/32" and never less than 1/64". Too small a gap may
+have been caused by beads of metal forming due to the heat of the spark.
+Too long a gap may have been caused by the points burning off.
+
+If the magneto and spark plugs are in good condition and the engine does
+not run satisfactorily, the setting should be verified according to
+instructions previously given, and, if necessary, readjusted.
+
+[Illustration: Fig. 66.--The Dixie Model 60 for Six-Cylinder Airplane
+Engine Ignition.]
+
+Be careful to observe that both the type "VN-1" and type "N-1" coils are
+so arranged that the spark occurs on the opening of the contacts of the
+timer. As this is just the reverse of the usual operation, it should be
+carefully noted when any change in the setting of the timer is made. The
+timer on the dual type magneto is adjusted so that the battery spark
+occurs about 5 deg. later than the magneto spark. This provides an
+automatic advance as soon as the switch is thrown to the magneto
+position "MAG." This relative timing can be easily adjusted by removing
+the interrupter and shifting the cam in the direction desired.
+
+
+THE DIXIE MAGNETO
+
+[Illustration: Fig. 67.--Installation Dimensions of Dixie Model 60
+Magneto.]
+
+The Dixie magneto, shown at Fig. 66, operates on a different principle
+than the rotary armature type. It is used on the Hall-Scott and other
+aviation engines. In this magneto the rotating member consists of two
+pieces of magnetic material separated by a non-magnetic center piece.
+This member constitutes true rotating poles for the magnet and rotates
+in a field structure, composed of two laminated field pieces, riveted
+between two non-magnetic rings. The bearings for the rotating poles are
+mounted in steel plates, which lie against the poles of the magnets.
+When the magnet poles rotate, the magnetic lines of force from each
+magnet pole are carried directly to the field pieces and through the
+windings, without reversal through the mass of the rotating member and
+with only a single air gap. There are no losses by flux reversal in the
+rotating part, such as take place in other machines, and this is said
+to account for the high efficiency of the instrument.
+
+[Illustration: Fig. 68.--The Rotating Elements of the Dixie Magneto.]
+
+And this "Mason Principle" involved in the operation of the Dixie is
+simplified by a glance at the field structure, consisting of the
+non-magnetic rings, assembled to which are the field pieces between
+which the rotating poles revolve (see Fig. 68). Rotating between the
+limbs of the magnets, these two pieces of magnetic material form true
+extensions to the poles of the magnets, and are, in consequence,
+_always_ of the _same_ polarity. It will be seen there is no reversal of
+the magnetism through them, and consequently no eddy current or
+hysteresis losses which are present in the usual rotor or inductor
+types. The simplicity features of construction stand out prominently
+here, in that there are no revolving windings, a detail entirely
+differing from the orthodox high-tension instrument. This simplicity
+becomes instantly apparent when it is found that the circuit breaker,
+instead of revolving as it does in other types, is stationary and that
+the whole breaker mechanism is exposed by simply turning the cover
+spring aside and removing cover. This makes inspection and adjustment
+particularly simple, and the fact that no special tool is necessary for
+adjustment of the platinum points--an ordinary small screw-driver is the
+whole "kit of tools" needed in the work of disassembling or
+assembling--is a feature of some value.
+
+[Illustration: Fig. 69.--Suggestions for Adjusting and Dismantling Dixie
+Magneto. A--Screw Driver Adjusts Contact Points. B--Distributor Block
+Removed. C--Taking off Magnets. D--Showing How Easily Condenser and High
+Tension Windings are Removed.]
+
+With dust- and water-protecting casing removed, and one of the magnets
+withdrawn, as in Fig. 69, the winding can be seen with its core resting
+on the field pole pieces and the primary lead attached to its side. An
+important feature of the high-tension winding is that the heads are of
+insulating material, and there is not the tendency for the high-tension
+current to jump to the side as in the ordinary armature type magneto.
+The high-tension current is carried to the distributor by means of an
+insulated block with a spindle, at one end of which is a spring brush
+bearing directly on the winding, thus shortening the path of the
+high-tension current and eliminating the use of rubber spools and
+insulating parts. The moving parts of the magneto need never be
+disturbed if the high-tension winding is to be removed. This winding
+constitutes all of the magneto windings, no external spark coil being
+necessary. The condenser is placed directly above the winding and is
+easily removable by taking out two screws, instead of being placed in an
+armature where it is inaccessible except to an expert, and where it
+cannot be replaced except at the factory whence it emanated.
+
+
+CARE OF THE DIXIE MAGNETO
+
+The bearings of the magneto are provided with oil cups and a few drops
+of light oil every 1,000 miles are sufficient. The breaker lever should
+be lubricated every 1,000 miles with a drop of light oil, applied with a
+tooth-pick. The proper distance between the platinum points when
+separated should not exceed .020 or one-fiftieth of an inch. A gauge of
+the proper size is attached to the screwdriver furnished with the
+magneto. The platinum contacts should be kept clean and properly
+adjusted. Should the contacts become pitted, a fine file should be used
+to smooth them in order to permit them to come into perfect contact. The
+distributor block should be removed occasionally and inspected for an
+accumulation of carbon dust. The inside of the distributor block should
+be cleaned with a cloth moistened with gasoline and then wiped dry with
+a clean cloth. When replacing the block, care must be exercised in
+pushing the carbon brush into the socket. Do not pull out the carbon
+brushes in the distributor because you think there is not enough tension
+on the small brass springs. In order to obtain the most efficient
+results, the normal setting of the spark-plug points should not exceed
+.025 of an inch, and it is advisable to have the gap just right before a
+spark-plug is inserted.
+
+The spark-plug electrodes may be easily set by means of the gauge
+attached to the screwdriver. _The setting of the spark-plug points is an
+important function which is usually overlooked, with the result that the
+magneto is blamed when it is not at fault._
+
+
+TIMING OF THE DIXIE MAGNETO
+
+[Illustration: Fig. 69A.--Sectional Views Outlining Construction of
+Dixie Magneto with Compound Distributor for Eight-Cylinder Engine
+Ignition.]
+
+In order to obtain the utmost efficiency from the engine, the magneto
+must be correctly timed to it. This operation is usually performed when
+the magneto is fitted to the engine at the factory. The correct setting
+may vary according to individuality of the engine, and some engines
+may require an earlier setting in order to obtain the best results.
+However, should the occasion arise to retime the magneto, the procedure
+is as follows: Rotate the crank-shaft of the engine until one of the
+pistons, preferably that of cylinder No. 1, is 1/16 of an inch ahead of
+the end of the compression stroke. With the timing lever in full retard
+position, the driving shaft of the magneto should be rotated in the
+direction in which it will be driven. The circuit breaker should be
+closely observed and when the platinum contact points are about to
+separate, the drive gear or coupling should be secured to the drive
+shaft of the magneto. Care should be taken not to alter the position of
+the magneto shaft when tightening the nut to secure the gear or
+coupling, after which the magneto should be secured to its base. Remove
+the distributor block and determine which terminal of the block is in
+contact with the carbon brush of the distributor finger and connect with
+plug wire leading to No. 1 cylinder to this terminal. Connect the
+remaining plug wires in turn according to the proper sequence of firing
+of the cylinders. (See the wiring diagram for a typical six-cylinder
+engine at Fig. 70.) A terminal on the end of the cover spring of the
+magneto is provided for the purpose of connecting the wire leading to a
+ground switch for stopping the engine.
+
+A special model or type of magneto is made for V engines which use a
+compound distributor construction instead of the simple type on the
+model illustrated and a different interior arrangement permits the
+production of four sparks per revolution of the rotors. This makes it
+possible to run the magneto slower than would be possible with the
+two-spark form. The application of two compound distributor magnetos of
+this type to a Thomas-Morse 135 horse-power motor of the eight-cylinder
+V pattern is clearly shown at Fig. 71.
+
+[Illustration: Fig. 70.--Wiring Diagram of Dixie Magneto Installation on
+Hall-Scott Six-Cylinder 125 Horse-Power Aeronautic Motor.]
+
+
+SPARK-PLUG DESIGN AND APPLICATION
+
+[Illustration: Fig. 71.--How Magneto Ignition is Installed on
+Thomas-Morse 135 Horse-Power Motor.]
+
+With the high-tension system of ignition the spark is produced by a
+current of high voltage jumping between two points which break the
+complete circuit, which would exist otherwise in the secondary coil and
+its external connections. The spark-plug is a simple device which
+consists of two terminal electrodes carried in a suitable shell member,
+which is screwed into the cylinder. Typical spark-plugs are shown in
+section at Fig. 72 and the construction can be easily understood. The
+secondary wire from the coil is attached to a terminal at the top of a
+central electrode member, which is supported in a bushing of some form
+of insulating material. The type shown at A employs a molded porcelain
+as an insulator, while that depicted at B uses a bushing of mica. The
+insulating bushing and electrode are housed in a steel body, which is
+provided with a screw thread at the bottom, by which means it is screwed
+into the combustion chamber.
+
+[Illustration: Fig. 72.--Spark-Plug Types Showing Construction and
+Arrangement of Parts.]
+
+When porcelain is used as an insulating material it is kept from direct
+contact with the metal portion by some form of yielding packing, usually
+asbestos. This is necessary because the steel and porcelain have
+different coefficients of expansion and some flexibility must be
+provided at the joints to permit the materials to expand differently
+when heated. The steel body of the plug which is screwed into the
+cylinder is in metallic contact with it and carries sparking points
+which form one of the terminals of the air gap over which the spark
+occurs. The current entering at the top of the plug cannot reach the
+ground, which is represented by the metal portion of the engine, until
+it has traversed the full length of the central electrode and overcome
+the resistance of the gap between it and the terminal point on the
+shell. The porcelain bushing is firmly seated against the asbestos
+packing by means of a brass screw gland which sets against a flange
+formed on the porcelain, and which screws into a thread at the upper
+portion of the plug body.
+
+The mica plug shown at B is somewhat simpler in construction than that
+shown at A. The mica core which keeps the central electrode separated
+from the steel body is composed of several layers of pure sheet mica
+wound around the steel rod longitudinally, and hundreds of stamped steel
+washers which are forced over this member and compacted under high
+pressure with some form of a binding material between them. Porcelain
+insulators are usually molded from high-grade clay and are approximately
+of the shapes desired by the designers of the plug. The central
+electrode may be held in place by mechanical means such as nuts,
+packings, and a shoulder on the rod, as shown at A. Another method
+sometimes used is to cement the electrode in place by means of some form
+of fire-clay cement. Whatever method of fastening is used, it is
+imperative that the joints be absolutely tight so that no gas can escape
+at the time of explosion. Porcelain is the material most widely used
+because it can be glazed so that it will not absorb oil, and it is
+subjected to such high temperature in baking that it is not liable to
+crack when heated.
+
+The spark-plugs may be screwed into any convenient part of the
+combustion chamber, the general practice being to install them in the
+caps over the inlet valves, or in the side of the combustion chamber, so
+the points will be directly in the path of the entering fresh gases from
+the carburetor.
+
+Other insulating materials sometimes used are glass, steatite (which is
+a form of soapstone) and lava. Mica and porcelain are the two common
+materials used because they give the best results. Glass is liable to
+crack, while lava or the soapstone insulating bushings absorb oil. The
+spark gap of the average plug is equal to about 1/32 of an inch for coil
+ignition and 1/40 of an inch when used in magneto circuits. A simple
+gauge for determining the gap setting is the thickness of an ordinary
+visiting card for magneto plugs, or a space equal to the thickness of a
+worn dime for a coil plug. The insulating bushings are made in a number
+of different ways, and while details of construction vary, spark-plugs
+do not differ essentially in design. The dimensions of the standardized
+plug recommended by the S. A. E. are shown at Fig. 73.
+
+[Illustration: Fig. 73.--Standard Airplane Engine Plug Suggested by S.
+A. E. Standards Committee.]
+
+It is often desirable to have a water-tight joint between the
+high-tension cable and the terminal screw on top of the insulating
+bushing of the spark-plug, especially in marine applications. The plug
+shown at C, Fig. 72, is provided with an insulating member or hood of
+porcelain, which is secured by a clip in such a manner that it makes a
+water-tight connection. Should the porcelain of a conventional form of
+plug become covered with water or dirty oil, the high-tension current is
+apt to run down this conducting material on the porcelain and reach the
+ground without having to complete its circuit by jumping the air gap and
+producing a spark. It will be evident that wherever a plug is exposed to
+the elements, which is often the case in airplane service, that it
+should be protected by an insulating hood which will keep the insulator
+dry and prevent short circuiting of the spark. The same end can be
+attained by slipping an ordinary rubber nipple over the porcelain
+insulator of any conventional plug and bringing up one end over the
+cable.
+
+
+TWO-SPARK IGNITION
+
+On most aviation engines, especially those having large cylinders, it is
+sometimes difficult to secure complete combustion by using a
+single-spark plug. If the combustion is not rapid the efficiency of the
+engine will be reduced proportionately. The compressed charge in the
+cylinder does not ignite all at once or instantaneously, as many assume,
+but it is the strata of gas nearest the plug which is ignited first.
+This in turn sets fire to consecutive layers of the charge until the
+entire mass is aflame. One may compare the combustion of gas in the
+gas-engine cylinder to the phenomenon which obtains when a heavy object
+is thrown into a pool of still water. First a small circle is seen at
+the point where the object has passed into the water, this circle in
+turn inducing other and larger circles until the whole surface of the
+pool has been agitated from the one central point. The method of
+igniting the gas is very similar, as the spark ignites the circle of gas
+immediately adjacent to the sparking point, and this circle in turn
+ignites a little larger one concentric with it. The second circle of
+flame sets fire to more of the gas, and finally the entire contents of
+the combustion chamber are burning.
+
+While ordinarily combustion is sufficiently rapid with a single plug so
+that the proper explosion is obtained at moderate engine speeds, if the
+engine is working fast and the cylinders are of large capacity more
+power may be obtained by setting fire to the mixture at two different
+points instead of but one. This may be accomplished by using two
+sparking-plugs in the cylinder instead of one, and experiments have
+shown that it is possible to gain from twenty-five to thirty per cent.
+in motor power at high speed with two-spark plugs, because the
+combustion of gas is accelerated by igniting the gas simultaneously in
+two places. The double-plug system on airplane engines is also a
+safeguard, as in event of failure of one plug in the cylinder the other
+would continue to fire the gas, and the engine will continue to function
+properly.
+
+In using magneto ignition some precautions are necessary relating to
+wiring and also the character of the spark-plugs employed. The conductor
+should be of good quality, have ample insulation, and be well protected
+from accumulations of oil, which would tend to decompose rubber
+insulation. It is customary to protect the wiring by running it through
+the conduits of fiber or metal tubing lined with insulating material.
+Multiple strand cables should be used for both primary and secondary
+wiring, and the insulation should be of rubber at least 3/16 inch thick.
+
+The spark-plugs commonly used for battery and coil ignition cannot
+always be employed when a magneto is fitted. The current produced by the
+mechanical generator has a greater amperage and more heat value than
+that obtained from transformer coils excited by battery current. The
+greater heat may burn or fuse the slender points used on some battery
+plugs and heavier electrodes are needed to resist the heating effect of
+the more intense arc. While the current has greater amperage it is not
+of as high potential or voltage as that commonly produced by the
+secondary winding of an induction coil, and it cannot overcome as much
+of a gap. Manufacturers of magneto plugs usually set the spark points
+about 1/64 of an inch apart. The most efficient magneto plug has a
+plurality of points so that when the distance between one set becomes
+too great the spark will take place between one of the other pairs of
+electrodes which are not separated by so great an air space.
+
+[Illustration: Fig. 74.--Special Mica Plug for Aviation Engines.]
+
+
+SPECIAL PLUGS FOR AIRPLANE WORK
+
+Airplane work calls for special construction of spark-plugs, owing to
+the high compression used in the engines and the fact that they are
+operated on open throttle practically all the time, thus causing a great
+deal of heat to be developed. The plug shown at Fig. 74 was recently
+described in "The Automobile," and has been devised especially for
+airplane engines and automobile racing power plants. The core C is built
+up of mica washers, and has square shoulders. As mica washers of
+different sizes may be used, and accurate machining, such as is
+necessary with conical clamping surfaces, is not required, the plug can
+be produced economically. The square shoulders of the core afford two
+gasket seats, and when the core is clamped in the shell by means of
+check nut E, it is accurately centered and a tight joint is formed. This
+construction also makes a shorter plug than where conical fits are used,
+thus improving the heat radiation through the stem. The lower end of the
+shell is provided with a baffle plate O, which tends to keep the oil
+away from the mica. There are perforations L in this baffle plate to
+prevent burnt gases being pocketed behind the baffle plate and
+pre-igniting the new charge. This construction also brings the firing
+point out into the firing chamber of the engine, and has all the other
+advantages of a closed-end plug. The stem P is made of brass or copper,
+on account of their superior heat conductivity, and the electrode J is
+swedged into the bottom of the stem, as shown at K, in a secure manner.
+
+The shell is finned, as shown at G, to provide greater heat radiating
+surface. There is also a fin F at the top of the stem, to increase the
+radiation of heat from the stem and electrode. The top of this finned
+portion is slightly countersunk, and the stem is riveted into same,
+thereby reducing the possibility of leakage past the threads on the
+stem. This finned portion is necked at A to take a slip terminal.
+
+In building up the core a small section of washers, I, is built up
+before the mica insulating tube D is placed on. This construction gives
+a better support to section I. Baffle plate O is bored out to allow the
+electrode J to pass through, and the clearance between baffle plate and
+electrode is made larger than the width of the gap between the firing
+points, so that there is no danger of the spark jumping from the
+electrode to the baffle plate.
+
+This plug will be furnished either with or without the finned portion,
+to meet individual requirements. The manufacturers lay special stress
+upon the simplicity of construction and upon the method of clamping,
+which is claimed to make the plug absolutely gas-tight.
+
+
+
+
+CHAPTER VII
+
+ Why Lubrication Is Necessary--Friction Defined--Theory of
+ Lubrication--Derivation of Lubricants--Properties of Cylinder
+ Oils--Factors Influencing Lubrication System Selection--Gnome
+ Type Engines Use Castor Oil--Hall-Scott Lubrication System--Oil
+ Supply by Constant Level Splash System--Dry Crank-Case System
+ Best for Airplane Engines--Why Cooling Systems Are Necessary--
+ Cooling Systems Generally Applied--Cooling by Positive Pump
+ Circulation--Thermo-Syphon System--Direct Air-Cooling Methods--
+ Air-Cooled Engine Design Considerations.
+
+
+WHY LUBRICATION IS NECESSARY
+
+The importance of minimizing friction at the various bearing surfaces of
+machines to secure mechanical efficiency is fully recognized by all
+mechanics, and proper lubricity of all parts of the mechanism is a very
+essential factor upon which the durability and successful operation of
+the motor car power plant depends. All of the moving members of the
+engine which are in contact with other portions, whether the motion is
+continuous or intermittent, of high or low velocity, or of rectilinear
+or continued rotary nature, should be provided with an adequate supply
+of oil. No other assemblage of mechanism is operated under conditions
+which are so much to its disadvantage as the motor car, and the tendency
+is toward a simplification of oiling methods so that the supply will be
+ample and automatically applied to the points needing it.
+
+In all machinery in motion the members which are in contact have a
+tendency to stick to each other, and the very minute projections which
+exist on even the smoothest of surfaces would have a tendency to cling
+or adhere to each other if the surfaces were not kept apart by some
+elastic and unctuous substance. This will flow or spread out over the
+surfaces and smooth out the inequalities existing which tend to produce
+heat and retard motion of the pieces relative to each other.
+
+A general impression which obtains is that well machined surfaces are
+smooth, but while they are apparently free from roughness, and no
+projections are visible to the naked eye, any smooth bearing surface,
+even if very carefully ground, will have a rough appearance if examined
+with a magnifying glass. An exaggerated condition to illustrate this
+point is shown at Fig. 75. The amount of friction will vary in
+proportion to the pressure on the surfaces in contact and will augment
+as the loads increase; the rougher surfaces will have more friction than
+smoother ones and soft bodies will produce more friction than hard
+substances.
+
+
+FRICTION DEFINED
+
+Friction is always present in any mechanism as a resisting force that
+tends to retard motion and bring all moving parts to a state of rest.
+The absorption of power by friction may be gauged by the amount of heat
+which exists at the bearing points. Friction of solids may be divided
+into two classes: sliding friction, such as exists between the piston
+and cylinder, or the bearings of a gas-engine, and rolling friction,
+which is that present when the load is supported by ball or roller
+bearings, or that which exists between the tires or the driving wheels
+and the road. Engineers endeavor to keep friction losses as low as
+possible, and much care is taken in all modern airplane engines to
+provide adequate methods of lubrication, or anti-friction bearings at
+all points where considerable friction exists.
+
+
+THEORY OF LUBRICATION
+
+The reason a lubricant is supplied to bearing points will be easily
+understood if one considers that these elastic substances flow between
+the close fitting surfaces, and by filling up the minute depressions in
+the surfaces and covering the high spots act as a cushion which absorbs
+the heat generated and takes the wear instead of the metallic bearing
+surface. The closer the parts fit together the more fluid the lubricant
+must be to pass between their surfaces, and at the same time it must
+possess sufficient body so that it will not be entirely forced out by
+the pressure existing between the parts.
+
+[Illustration: Fig. 75.--Showing Use of Magnifying Glass to Demonstrate
+that Apparently Smooth Metal Surfaces May Have Minute Irregularities
+which Produce Friction.]
+
+Oils should have good adhesive, as well as cohesive, qualities. The
+former are necessary so that the oil film will cling well to the
+surfaces of the bearings; the latter, so the oil particles will cling
+together and resist the tendency to separation which exists all the time
+the bearings are in operation. When used for gas-engine lubrication the
+oil should be capable of withstanding considerable heat in order that it
+will not be vaporized by the hot portions of the cylinder. It should
+have sufficient cold test so that it will remain fluid and flow readily
+at low temperature. Lubricants should be free from acid, or alkalies,
+which tend to produce a chemical action with metals and result in
+corrosion of the parts to which they are applied. It is imperative that
+the oil be exactly the proper quality and nature for the purpose
+intended and that it be applied in a positive manner. The requirements
+may be briefly summarized as follows:
+
+First--It must have sufficient body to prevent seizing of the parts to
+which it is applied and between which it is depended upon to maintain an
+elastic film, and yet it must not have too much viscosity, in order to
+minimize the internal or fluid friction which exists between the
+particles of the lubricant itself.
+
+Second--The lubricant must not coagulate or gum; must not injure the
+parts to which it is applied, either by chemical action or by producing
+injurious deposits, and it should not evaporate readily.
+
+Third--The character of the work will demand that the oil should not
+vaporize when heated or thicken to such a point that it will not flow
+readily when cold.
+
+Fourth--The oil must be free from acid, alkalies, animal or vegetable
+fillers, or other injurious agencies.
+
+Fifth--It must be carefully selected for the work required and should be
+a good conductor of heat.
+
+
+DERIVATION OF LUBRICANTS
+
+The first oils which were used for lubricating machinery were obtained
+from animal and vegetable sources, though at the present time most
+unguents are of mineral derivation. Lubricants may exist as fluids,
+semifluids, or solids. The viscosity will vary from light spindle or
+dynamo oils, which have but little more body than kerosene, to the
+heaviest greases and tallows. The most common solid employed as a
+lubricant is graphite, sometimes termed "plumbago" or "black lead." This
+substance is of mineral derivation.
+
+The disadvantage of oils of organic origin, such as those obtained from
+animal fats or vegetable substances, is that they will absorb oxygen
+from the atmosphere, which causes them to thicken or become rancid.
+Such oils have a very poor cold test, as they solidify at comparatively
+high temperatures, and their flashing point is so low that they cannot
+be used at points where much heat exists. In most animal oils various
+acids are present in greater or less quantities, and for this reason
+they are not well adapted for lubricating metallic surfaces which may be
+raised high enough in temperature to cause decomposition of the oils.
+
+Lubricants derived from the crude petroleum are called "Oleonaphthas"
+and they are a product of the process of refining petroleum through
+which gasoline and kerosene are obtained. They are of lower cost than
+vegetable or animal oil, and as they are of non-organic origin, they do
+not become rancid or gummy by constant exposure to the air, and they
+will have no corrosive action on metals because they contain no
+deleterious substances in chemical composition. By the process of
+fractional distillation mineral oils of all grades can be obtained. They
+have a lower cold and higher flash test and there is not the liability
+of spontaneous combustion that exists with animal oils.
+
+The organic oils are derived from fatty substances, which are present in
+the bodies of all animals and in some portions of plants. The general
+method of extracting oil from animal bodies is by a rendering process,
+which consists of applying sufficient heat to liquefy the oil and then
+separating it from the tissue with which it is combined by compression.
+The only oil which is used to any extent in gas-engine lubrication that
+is not of mineral derivation is castor oil. This substance has been used
+on high-speed racing automobile engines and on airplane power plants. It
+is obtained from the seeds of the castor plant, which contain a large
+percentage of oil.
+
+Among the solid substances which may be used for lubricating purposes
+may be mentioned tallow, which is obtained from the fat of animals, and
+graphite and soapstone, which are of mineral derivation. Tallow is
+never used at points where it will be exposed to much heat, though it
+is often employed as a filler for greases used in transmission gearing
+of autos. Graphite is sometimes mixed with oil and applied to cylinder
+lubrication, though it is most often used in connection with greases in
+the landing gear parts and for coating wires and cables of the airplane.
+Graphite is not affected by heat, cold, acids, or alkalies, and has a
+strong attraction for metal surfaces. It mixes readily with oils and
+greases and increases their efficiency in many applications. It is
+sometimes used where it would not be possible to use other lubricants
+because of extremes of temperature.
+
+The oils used for cylinder lubrication are obtained almost exclusively
+from crude petroleum derived from American wells. Special care must be
+taken in the selection of crude material, as every variety will not
+yield oil of the proper quality to be used as a cylinder lubricant. The
+crude petroleum is distilled as rapidly as possible with fire heat to
+vaporize off the naphthas and the burning oils. After these vapors have
+been given off superheated steam is provided to assist in distilling.
+When enough of the light elements have been eliminated the residue is
+drawn off, passed through a strainer to free it from grit and earthy
+matters, and is afterwards cooled to separate the wax from it. This is
+the dark cylinder oil and is the grade usually used for steam-engine
+cylinders.
+
+
+PROPERTIES OF CYLINDER OILS
+
+The oil that is to be used in the gasoline engine must be of high
+quality, and for that reason the best grades are distilled in a vacuum
+that the light distillates may be separated at much lower temperatures
+than ordinary conditions of distilling permit. If the degree of heat is
+not high the product is not so apt to decompose and deposit carbon. If
+it is desired to remove the color of the oil which is caused by free
+carbon and other impurities it can be accomplished by filtering the oil
+through charcoal. The greater the number of times the oil is filtered,
+the lighter it will become in color. The best cylinder oils have flash
+points usually in excess of 500 degrees F., and while they have a high
+degree of viscosity at 100 degrees F. they become more fluid as the
+temperature increases.
+
+The lubricating oils obtained by refining crude petroleum may be divided
+into three classes:
+
+First--The natural oils of great body which are prepared for use by
+allowing the crude material to settle in tanks at high temperature and
+from which the impurities are removed by natural filtration. These oils
+are given the necessary body and are free from the volatile substances
+they contain by means of superheated steam which provides a source of
+heat.
+
+Second--Another grade of these natural oils which are filtered again at
+high temperatures and under pressure through beds of animal charcoal to
+improve their color.
+
+Third--Pale, limpid oils, obtained by distillation and subsequent
+chemical treatment from the residuum produced in refining petroleum to
+obtain the fuel oils.
+
+Authorities agree that any form of mixed oil in which animal and mineral
+lubricants are combined should never be used in the cylinder of a gas
+engine as the admixture of the lubricants does not prevent the
+decomposition of the organic oil into the glycerides and fatty acids
+peculiar to the fat used. In a gas-engine cylinder the flame tends to
+produce more or less charring. The deposits of carbon will be much
+greater with animal oils than with those derived from the petroleum base
+because the constituents of a fat or tallow are not of the same volatile
+character as those which comprise the hydro-carbon oils which will
+evaporate or volatilize before they char in most instances.
+
+
+FACTORS INFLUENCING LUBRICATION SYSTEM SELECTION
+
+The suitability of oil for the proper and efficient lubrication of all
+internal combustion engines is determined chiefly by the following
+factors:
+
+1. Type of cooling system (operating temperatures).
+
+2. Type of lubricating system (method of applying oil to the moving
+parts).
+
+3. Rubbing speeds of contact surfaces.
+
+Were the operating temperatures, bearing surface speeds and lubrication
+systems identical, a single oil could be used in all engines with equal
+satisfaction. The only change then necessary in viscosity would be that
+due to climatic conditions. As engines are now designed, only three
+grades of oil are necessary for the lubrication of all types with the
+exception of Knight, air-cooled and some engines which run continuously
+at full load. In the specification of engine lubricants the feature of
+load carried by the engine should be carefully considered.
+
+_Full Load Engines._
+
+ 1. Marine.
+ 2. Racing automobile.
+ 3. Aviation.
+ 4. Farm tractor.
+ 5. Some stationary.
+
+_Variable Load Engines._
+
+ 1. Pleasure automobile.
+ 2. Commercial vehicle.
+ 3. Motor cycle.
+ 4. Some stationary.
+
+Of the forms outlined, the only one we have any immediate concern about
+is the airplane power plant. The Platt & Washburn Refining Company, who
+have made a careful study of the lubrication problem as applied to all
+types of engines, have found a peculiar set of conditions to apply to
+oiling high-speed constant-duty or "full-load" engines. Modern airplane
+engines are designed to operate continuously at a fairly uniform high
+rotative speed and at full load over long periods of time. As a sequence
+to this heavy duty the operating temperatures are elevated. For the
+sake of extreme lightness in weight of all parts, very thin alloy steel
+aluminum or cast iron pistons are fitted and the temperature of the thin
+piston heads at the center reaches anywhere between 600 deg. and 1,400 deg.
+Fahr., as in automobile racing engines. Freely exposed to such intense
+heat hydro-carbon oils are partially "cracked" into light and heavy
+products or polymerized into solid hydro-carbons. From these facts it
+follows that only heavy mineral oils of low carbon residue and of the
+greatest chemical purity and stability should be used to secure good
+lubrication. In all cases the oil should be sufficiently heavy to assure
+the highest horse-power and fuel and oil economy compatible with perfect
+lubrication, avoiding, at the same time, carbonization and ignition
+failure. When aluminum pistons are used their superior heat-conducting
+properties aid materially in reducing the rate of oil destruction.
+
+The extraordinary evolutions described by airplanes in flight make it a
+matter of vital necessity to operate engines inclined at all angles to
+the vertical as well as in an upside-down position. To meet this
+situation lubricating systems have been elaborated so as to deliver an
+abundance of oil where needed and to eliminate possible flooding of
+cylinders. This is done by applying a full force feed system,
+distributing oil under considerable pressure to all working parts.
+Discharged through the bearings, the oil drains down to the suction side
+of a second pump located in the bottom of the base chamber. This pump
+being of greater capacity than the first prevents the accumulation of
+oil in the crank-case, and forces it to a separate oil reservoir-cooler,
+whence it flows back in rapid circulation to the pump feeding the
+bearings. With this arrangement positive lubrication is entirely
+independent of engine position. The lubricating system of the
+Thomas-Morse aviation engines, which is shown at Fig. 76, is typical of
+current practice.
+
+[Illustration: Fig. 76.--Pressure Feed Oiling System of Thomas Aviation
+Engine Includes Oil Cooling Means.]
+
+
+GNOME TYPE ENGINES USE CASTOR OIL
+
+The construction and operation of rotative radial cylinder engines
+introduce additional difficulties of lubrication to those already
+referred to and merit especial attention. Owing to the peculiar
+alimentation systems of Gnome type engines, atomized gasoline mixed with
+air is drawn through the hollow stationary crank-shaft directly into the
+crank-case which it fills on the way to the cylinders. Therein lies the
+trouble. Hydrocarbon oils are soon dissolved by the gasoline and washed
+off, leaving the bearing surfaces without adequate protection and
+exposed to instant wear and destruction. So castor oil is resorted to as
+an indispensable but unfortunate compromise. Of vegetable origin, it
+leaves a much more bulky carbon deposit in the explosion chambers than
+does mineral oil and its great affinity for oxygen causes the formation
+of voluminous gummy deposit in the crank-case. Engines employing it need
+to be dismounted and thoroughly scraped out at frequent intervals. It is
+advisable to use only unblended chemically pure castor oil in rotative
+engines, first by virtue of its insolubility in gasoline and second
+because its extra heavy body can resist the high temperature of
+air-cooled cylinders.
+
+
+HALL-SCOTT LUBRICATION SYSTEM
+
+[Illustration: Fig. 77.--Diagram of Oiling System, Hall-Scott Type A 125
+Horse-Power Engine.]
+
+The oiling system of the Hall-Scott type A-5 125 horse-power engine is
+clearly shown at Fig. 77. It is completely described in the instruction
+book issued by the company from which the following extracts are
+reproduced by permission. Crank-shaft, connecting rods and all other
+parts within the crank-case and cylinders are lubricated directly or
+indirectly by a force-feed oiling system. The cylinder walls and wrist
+pins are lubricated by oil spray thrown from the lower end of connecting
+rod bearings. This system is used only upon A-5 engines. Upon A-7a and
+A-5a engines a small tube supplies oil from connecting rod bearing
+directly upon the wrist pin. The oil is drawn from the strainer located
+at the lowest portion of the lower crank-case, forced around the main
+intake manifold oil jacket. From here it is circulated to the main
+distributing pipe located along the lower left hand side of upper
+crank-case. The oil is then forced directly to the lower side of
+crank-shaft, through holes drilled in each main bearing cup. Leakage
+from these main bearings is caught in scuppers placed upon the cheeks of
+the crank-shafts furnishing oil under pressure to the connecting rod
+bearings. A-7a and A-5a engines have small tubes leading from these
+bearings which convey the oil under pressure to the wrist pins.
+
+A bi-pass located at the front end of the distributing oil pipe can be
+regulated to lessen or raise the pressure. By screwing the valve in, the
+pressure will raise and more oil will be forced to the bearings. By
+unscrewing, pressure is reduced and less oil is fed. A-7a and A-5a
+engines have oil relief valves located just off of the main oil pump in
+the lower crank-case. This regulates the pressure at all times so that
+in cold weather there will be no danger of bursting oil pipes due to
+excessive pressure. If it is found the oil pressure is not maintained at
+a high enough level, inspect this valve. A stronger spring will not
+allow the oil to bi-pass so freely, and consequently the pressure will
+be raised; a weaker spring will bi-pass more oil and reduce the oil
+pressure materially. Independent of the above-mentioned system, a small,
+directly driven rotary oiler feeds oil to the base of each individual
+cylinder. The supply of oil is furnished by the main oil pump located in
+the lower crank-case. A small sight-feed regulator is furnished to
+control the supply of oil from this oiler. This instrument should be
+placed higher than the auxiliary oil distributor itself to enable the
+oil to drain by gravity feed to the oiler. If there is no available
+place with the necessary height in the front seat of plane, connect it
+directly to the intake L fitting on the oiler in an upright position. It
+should be regulated with full open throttle to maintain an oil level in
+the glass, approximately half way.
+
+An oil pressure gauge is provided. This should be run to the pilot's
+instrument board. The gauge registers the oil pressure upon the
+bearings, also determining its circulation. Strict watch should be
+maintained of this instrument by pilot, and if for any reason its hand
+should drop to 0 the motor should be immediately stopped and the trouble
+found before restarting engine. Care should be taken that the oil does
+not work up into the gauge, as it will prevent the correct gauge
+registering of oil pressure. The oil pressure will vary according to
+weather conditions and viscosity of oil used. In normal weather, with
+the engine properly warmed up, the pressure will register on the oil
+gauge from 5 to 10 pounds when the engine is turning from 1,275 to 1,300
+r. p. m. This does not apply to all aviation engines, however, as the
+proper pressure advised for the Curtiss OX-2 motor is from 40 to 55
+pounds at the gauge.
+
+The oil sump plug is located at the lowest point of the lower
+crank-case. This is a combination dirt, water and sediment trap. It is
+easily removed by unscrewing. Oil is furnished mechanically to the
+cam-shaft housing under pressure through a small tube leading from the
+main distributing pipe at the propeller end of engine directly into the
+end of cam-shaft housing. The opposite end of this housing is amply
+relieved to allow the oil to rapidly flow down upon cam-shaft, magneto,
+pinion-shaft, and crank-shaft gears, after which it returns to lower
+crank-case. An outside overflow pipe is also provided to carry away the
+surplus oil.
+
+
+DRAINING OIL FROM CRANK-CASE
+
+The oil strainer is placed at the lowest point of the lower crank-case.
+This strainer should be removed after every five to eight hours running
+of the engine and cleaned thoroughly with gasoline. It is also advisable
+to squirt distillate up into the case through the opening where the
+strainer has been removed. Allow this distillate to drain out thoroughly
+before replacing the plug with strainer attached. Be sure gasket is in
+place on plug before replacing. Pour new oil in through either of the
+two breather pipes on exhaust side of motor. Be sure to replace strainer
+screens if removed. If, through oversight, the engine does not receive
+sufficient lubrication and begins to heat or pound, it should be stopped
+immediately. After allowing engine to cool pour at least three gallons
+of oil into oil sump. Fill radiator with water after engine has cooled.
+Should there be apparent damage, the engine should be thoroughly
+inspected immediately without further running. If no obvious damage has
+been done, the engine should be given a careful examination at the
+earliest opportunity to see that the running without oil has not burned
+the bearings or caused other trouble.
+
+Oils best adapted for Hall-Scott engines have the following properties:
+A flash test of not less than 400 deg. F.; viscosity of not less than 75
+to 85 taken at 21 deg. F. with Saybolt's Universal Viscosimeter.
+
+_Zeroline heavy duty oil_, manufactured by the Standard Oil Company of
+California; also,
+
+_Gargoyle mobile B oil_, manufactured by the Vacuum Oil Company, both
+fulfill the above specifications. One or the other of these oils can be
+obtained all over the world.
+
+Monogram extra heavy is also recommended.
+
+
+OIL SUPPLY BY CONSTANT LEVEL SPLASH SYSTEM
+
+The splash system of lubrication that depends on the connecting rod to
+distribute the lubricant is one of the most successful and simplest
+forms for simple four- and six-cylinder vertical automobile engines, but
+is not as well adapted to the oiling of airplane power plants for
+reasons previously stated. If too much oil is supplied the surplus will
+work past the piston rings and into the combustion chamber, where it
+will burn and cause carbon deposits. Too much oil will also cause an
+engine to smoke and an excess of lubricating oil is usually manifested
+by a bluish-white smoke issuing from the exhaust.
+
+A good method of maintaining a constant level of oil for the successful
+application of the splash system is shown at Fig. 78. The engine base
+casting includes a separate chamber which serves as an oil container and
+which is below the level of oil in the crank-case. The lubricant is
+drawn from the sump or oil container by means of a positive oil pump
+which discharges directly into the engine case. The level is maintained
+by an overflow pipe which allows all excess lubricant to flow back into
+the oil container at the bottom of the cylinder. Before passing into the
+pump again the oil is strained or filtered by a screen of wire gauze and
+all foreign matter removed. Owing to the rapid circulation of the oil it
+may be used over and over again for quite a period of time. The oil is
+introduced directly into the crank-case by a breather pipe and the level
+is indicated by a rod carried by a float which rises when the container
+is replenished and falls when the available supply diminishes. It will
+be noted that with such system the only apparatus required besides the
+oil tank which is cast integral with the bottom of the crank-case is a
+suitable pump to maintain circulation of oil. This member is always
+positively driven, either by means of shaft and universal coupling or
+direct gearing. As the system is entirely automatic in action, it will
+furnish a positive supply of oil at all desired points, and it cannot be
+tampered with by the inexpert because no adjustments are provided or
+needed.
+
+
+DRY CRANK-CASE SYSTEM BEST FOR AIRPLANE ENGINES
+
+[Illustration: Fig. 78.--Sectional View of Typical Motor Showing Parts
+Needing Lubrication and Method of Applying Oil by Constant Level Splash
+System. Note also Water Jacket and Spaces for Water Circulation.]
+
+In most airplane power plants it is considered desirable to supply the
+oil directly to the parts needing it by suitable leads instead of
+depending solely upon the distributing action of scoops on the
+connecting rod big ends. A system of this nature is shown at Fig. 77.
+The oil is carried in the crank-case, as is common practice, but the
+normal oil level is below the point where it will be reached by the
+connecting rod. It is drawn from the crank-case by a plunger pump which
+directs it to a manifold leading directly to conductors which supply the
+main journals. After the oil has been used on these points it drains
+back into the bottom of the crank-case. An excess is provided which is
+supplied to the connecting rod ends by passages drilled into the webs of
+the crank-shaft and part way into the crank-pins as shown by the dotted
+lines. The oil which is present at the connecting rod crank-pins is
+thrown off by centrifugal force and lubricates the cylinder walls and
+other internal parts. Regulating screws are provided so that the amount
+of oil supplied the different points may be regulated at will. A relief
+check valve is installed to take care of excess lubricant and to allow
+any oil that does not pass back into the pipe line to overflow or
+bi-pass into the main container.
+
+[Illustration: Fig. 79.--Pressure Feed Oil-Supply System of Airplane
+Power Plants has Many Good Features.]
+
+A simple system of this nature is shown graphically in a phantom view of
+the crank-case at Fig. 79, in which the oil passages are made specially
+prominent. The oil is taken from a reservoir at the bottom of the engine
+base by the usual form of gear oil pump and is supplied to a main feed
+manifold which extends the length of the crank-case. Individual
+conductors lead to the five main bearings, which in turn supply the
+crank-pins by passages drilled through the crank-shaft web. In this
+power plant the connecting rods are hollow section bronze castings and
+the passage through the center of the connecting rod serves to convey
+the lubricant from the crank-pins to the wrist-pins. The cylinder walls
+are oiled by the spray of lubricant thrown off the revolving crank-shaft
+by centrifugal force. Oil projection by the dippers on the connecting
+rod ends from constant level troughs is unequal upon the cylinder walls
+of the two-cylinder blocks of an eight- or twelve-cylinder V engine.
+This gives rise, on one side of the engine, to under-lubrication, and,
+on the other side, to over-lubrication, as shown at Fig. 80, A. This
+applies to all modifications of splash lubricating systems.
+
+When a force-feed lubricating system is used, the oil, escaping past the
+cheeks of both ends of the crank-pin bearings, is thrown off at a
+tangent to the crank-pin circle in all directions, supplying the
+cylinders on both sides with an equal quantity of oil, as at Fig. 80, B.
+
+
+WHY COOLING SYSTEMS ARE NECESSARY
+
+The reader should understand from preceding chapters that the power of
+an internal-combustion motor is obtained by the rapid combustion and
+consequent expansion of some inflammable gas. The operation in brief is
+that when air or any other gas or vapor is heated, it will expand and
+that if this gas is confined in a space which will not permit expansion,
+pressure will be exerted against all sides of the containing chamber.
+The more a gas is heated, the more pressure it will exert upon the walls
+of the combustion chamber it confines. Pressure in a gas may be
+created by increasing its temperature and inversely heat may be created
+by pressure. When a gas is compressed its total volume is reduced and
+the temperature is augmented.
+
+[Illustration: Fig. 80.--Why Pressure Feed System is Best for
+Eight-Cylinder Vee Airplane Engines.]
+
+The efficiency of any form of heat engine is determined by the power
+obtained from a certain fuel consumption. A definite amount of energy
+will be liberated in the form of heat when a pound of any fuel is
+burned. The efficiency of any heat engine is proportional to the power
+developed from a definite quantity of fuel with the least loss of
+thermal units. If the greater proportion of the heat units derived by
+burning the explosive mixture could be utilized in doing useful work,
+the efficiency of the gasoline engine would be greater than that of any
+other form of energizing power. There is a great loss of heat from
+various causes, among which can be cited the reduction of pressure
+through cooling the motor and the loss of heat through the exhaust
+valves when the burned gases are expelled from the cylinder.
+
+The loss through the water jacket of the average automobile power plant
+is over 50 per cent. of the total fuel efficiency. This means that more
+than half of the heat units available for power are absorbed and
+dissipated by the cooling water. Another 16 per cent. is lost through
+the exhaust valve, and but 33-1/3 per cent. of the heat units do useful
+work. The great loss of heat through the cooling systems cannot be
+avoided, as some method must be provided to keep the temperature of the
+engine within proper bounds. It is apparent that the rapid combustion
+and continued series of explosions would soon heat the metal portions of
+the engine to a red heat if some means were not taken to conduct much of
+this heat away. The high temperature of the parts would burn the
+lubricating oil, even that of the best quality, and the piston and rings
+would expand to such a degree, especially when deprived of oil, that
+they would seize in the cylinder. This would score the walls, and the
+friction which ensued would tend to bind the parts so tightly that the
+piston would stick, bearings would be burned out, the valves would warp,
+and the engine would soon become inoperative.
+
+[Illustration: Fig. 81.--Operating Temperatures of Automobile Engine
+Parts Useful as a Guide to Understand Airplane Power Plant Heat.]
+
+The best temperature to secure efficient operation is one on which
+considerable difference of opinion exists among engineers. The fact that
+the efficiency of an engine is dependent upon the ratio of heat
+converted into useful work compared to that generated by the explosion
+of the gas is an accepted fact. It is very important that the engine
+should not get too hot, and on the other hand it is equally vital that
+the cylinders be not robbed of too much heat. The object of cylinder
+cooling is to keep the temperature of the cylinder below the danger
+point, but at the same time to have it as high as possible to secure
+maximum power from the gas burned. The usual operating temperatures of
+an automobile engine are shown at Fig. 81, and this can be taken as an
+approximation of the temperatures apt to exist in an airplane engine of
+conventional design as well when at ground level or not very high in the
+air. The newer very high compression airplane engines in which
+compressions of eight or nine atmospheres are used, or about 125 pounds
+per square inch, will run considerably hotter than the temperatures
+indicated.
+
+
+COOLING SYSTEMS GENERALLY APPLIED
+
+There are two general systems of engine cooling in common use, that in
+which water is heated by the absorption of heat from the engine and then
+cooled by air, and the other method in which the air is directed onto
+the cylinder and absorbs the heat directly instead of through the medium
+of water. When the liquid is employed in cooling it is circulated
+through jackets which surround the cylinder casting and the water may be
+kept in motion by two methods. The one generally favored is to use a
+positive circulating pump of some form which is driven by the engine to
+keep the water in motion. The other system is to utilize a natural
+principle that heated water is lighter than cold liquid and that it will
+tend to rise to the top of the cylinder when it becomes heated to the
+proper temperature and cooled water takes its place at the bottom of the
+water jacket.
+
+Air-cooling methods may be by radiation or convection. In the former
+case the effective outer surface of the cylinder is increased by the
+addition of flanges machined or cast thereon, and the air is depended on
+to rise from the cylinder as heated and be replaced by cooler air. This,
+of course, is found only on stationary engines. When a positive air
+draught is directed against the cylinder by means of the propeller slip
+stream in an airplane, cooling is by convection and radiation both.
+Sometimes the air draught may be directed against the cylinder walls by
+some form of jacket which confines it to the heated portions of the
+cylinder.
+
+
+COOLING BY POSITIVE WATER CIRCULATION
+
+[Illustration: Fig. 82.--Water Cooling of Salmson Seven-Cylinder Radial
+Airplane Engine.]
+
+A typical water-cooling system in which a pump is depended upon to
+promote circulation of the cooling liquid is shown at Figs. 82 and 83.
+The radiator is carried at the front end of the fuselage in most cases,
+and serves as a combined water tank and cooler, but in some cases it is
+carried at the side of the engine, as in Fig. 84, or attached to the
+central portion of the aerofoil or wing structure. It is composed of an
+upper and lower portion joined together by a series of pipes which may
+be round and provided with a series of fins to radiate the heat, or
+which may be flat in order to have the water pass through in thin sheets
+and cool it more easily. Cellular or honeycomb coolers are composed of a
+large number of bent tubes which will expose a large area of surface to
+the cooling influence of the air draught forced through the radiator
+either by the forward movement of the vehicle or by some type of fan.
+The cellular and flat tube types have almost entirely displaced the
+flange tube radiators which were formerly popular because they cool the
+water more effectively, and may be made lighter than the tubular
+radiator could be for engines of the same capacity.
+
+[Illustration: Fig. 83.--How Water Cooling System of Thomas Airplane
+Engine is Installed in Fuselage.]
+
+The water is drawn from the lower header of the radiator by the pump and
+is forced through a manifold to the lower portion of the water jackets
+of the cylinder. It becomes heated as it passes around the cylinder
+walls and combustion chambers and the hot water passes out of the top of
+the water jacket to the upper portion of the radiator. Here it is
+divided in thin streams and directed against comparatively cool metal
+which abstracts the heat from the water. As it becomes cooler it falls
+to the bottom of the radiator because its weight increases as the
+temperature becomes lower. By the time it reaches the lower tank of the
+radiator it has been cooled sufficiently so that it may be again passed
+around the cylinders of the motor. The popular form of circulating pump
+is known as the "centrifugal type" because a rotary impeller of
+paddle-wheel form throws water which it receives at a central point
+toward the outside and thus causes it to maintain a definite rate of
+circulation. The pump is always a separate appliance attached to the
+engine and driven by positive gearing or direct-shaft connection. The
+centrifugal pump is not as positive as the gear form, and some
+manufacturers prefer the latter because of the positive pumping
+features. They are very simple in form, consisting of a suitable cast
+body in which a pair of spur pinions having large teeth are carried. One
+of these gears is driven by suitable means, and as it turns the other
+member they maintain a flow of water around the pump body. The pump
+should always be installed in series with the water pipe which conveys
+the cool liquid from the lower compartment of the radiator to the
+coolest portion of the water jacket.
+
+[Illustration: Fig. 84.--Finned Tube Radiators at the Side of Hall-Scott
+Airplane Power Plant Installed in Standard Fuselage.]
+
+
+WATER CIRCULATION BY NATURAL SYSTEM
+
+Some automobile engineers contend that the rapid water circulation
+obtained by using a pump may cool the cylinders too much, and that the
+temperature of the engine may be reduced so much that the efficiency
+will be lessened. For this reason there is a growing tendency to use the
+natural method of water circulation as the cooling liquid is supplied to
+the cylinder jackets just below the boiling point and the water issues
+from the jacket at the top of the cylinder after it has absorbed
+sufficient heat to raise it just about to the boiling point.
+
+As the water becomes heated by contact with the hot cylinder and
+combustion-chamber walls it rises to the top of the water jacket, flows
+to the cooler, where enough of the heat is absorbed to cause it to
+become sensibly greater in weight. As the water becomes cooler, it falls
+to the bottom of the radiator and it is again supplied to the water
+jacket. The circulation is entirely automatic and continues as long as
+there is a difference in temperature between the liquid in the water
+spaces of the engine and that in the cooler. The circulation becomes
+brisker as the engine becomes hotter and thus the temperature of the
+cylinders is kept more nearly to a fixed point. With the thermosyphon
+system the cooling liquid is nearly always at its boiling point, whereas
+if the circulation is maintained by a pump the engine will become cooler
+at high speed and will heat up more at low speed.
+
+With the thermosyphon, or natural system of cooling, more water must be
+carried than with the pump-maintained circulation methods. The water
+spaces around the cylinders should be larger, the inlet and discharge
+water manifolds should have greater capacity, and be free from sharp
+corners which might impede the flow. The radiator must also carry more
+water than the form used in connection with the pump because of the
+brisker pump circulation which maintains the engine temperature at a
+lower point. Consideration of the above will show why the pump system is
+almost universally used in connection with airplane power plant cooling.
+
+
+DIRECT AIR-COOLING METHODS
+
+The earliest known method of cooling the cylinder of gas-engines was by
+means of a current of air passed through a jacket which confined it
+close to the cylinder walls and was used by Daimler on his first
+gas-engine. The gasoline engine of that time was not as efficient as the
+later form, and other conditions which materialized made it desirable to
+cool the engine by water. Even as gasoline engines became more and more
+perfected there has always existed a prejudice against air cooling,
+though many forms of engines have been used, both in automobile and
+aircraft applications where the air-cooling method has proven to be very
+practical.
+
+The simplest system of air cooling is that in which the cylinders are
+provided with a series of flanges which increase the effective radiating
+surface of the cylinder and directing an air-current from a fan against
+the flanges to absorb the heat. This increase in the available radiating
+surface of an air-cooled cylinder is necessary because air does not
+absorb heat as readily as water and therefore more surface must be
+provided that the excess heat be absorbed sufficiently fast to prevent
+distortion of the cylinders. Air-cooling systems are based on a law
+formulated by Newton, which is: "The rate for cooling for a body in a
+uniform current of air is directly proportional to the speed of the air
+current and the amount of radiating surface exposed to the cooling
+effect."
+
+
+AIR-COOLED ENGINE DESIGN CONSIDERATIONS
+
+[Illustration: Fig. 85.--Anzani Testing His Five-Cylinder Air Cooled
+Aviation Motor Installed in Bleriot Monoplane. Note Exposure of Flanged
+Cylinders to Propeller Slip Stream.]
+
+There are certain considerations which must be taken into account in
+designing an air-cooled engine, which are often overlooked in those
+forms cooled by water. Large valves must be provided to insure rapid
+expulsion of the flaming exhaust gas and also to admit promptly the
+fresh cool mixture from the carburetor. The valves of air-cooled engines
+are usually placed in the cylinder-head, in order to eliminate any
+pockets or sharp passages which would impede the flow of gas or retain
+some of the products of combustion and their heat. When high power is
+desired multiple-cylinder engines should be used, as there is a certain
+limit to the size of a successful air-cooled cylinder. Much better
+results are secured from those having small cubical contents because the
+heat from small quantities of gas will be more quickly carried off than
+from greater amounts. All successful engines of the aviation type which
+have been air-cooled have been of the multiple-cylinder type.
+
+An air-cooled engine must be placed in the fuselage, as at Fig. 85, in
+such a way that there will be a positive circulation of air around it
+all the time that it is in operation. The air current may be produced by
+the tractor screw at the front end of the motor, or by a suction or
+blower fan attached to the crank-shaft as in the Renault engine or by
+rotating the cylinders as in the Le Rhone and Gnome motors. Greater care
+is required in lubrication of the air-cooled cylinders and only the best
+quality of oil should be used to insure satisfactory oiling.
+
+The combustion chambers must be proportioned so that distribution of
+metal is as uniform as possible in order to prevent uneven expansion
+during increase in temperature and uneven contraction when the cylinder
+is cooled. It is essential that the inside walls of the combustion
+chamber be as smooth as possible because any sharp angle or projection
+may absorb sufficient heat to remain incandescent and cause trouble by
+igniting the mixture before the proper time. The best grades of cast
+iron or steel should be used in the cylinder and piston and the machine
+work must be done very accurately so the piston will operate with
+minimum friction in the cylinder. The cylinder bore should not exceed
+4-1/2 or 5 inches and the compression pressure should never exceed 75
+pounds absolute, or about five atmospheres, or serious overheating will
+result.
+
+As an example of the care taken in disposing of the exhaust gases in
+order to obtain practical air-cooling, some cylinders are provided with
+a series of auxiliary exhaust ports uncovered by the piston when it
+reaches the end of its power stroke. The auxiliary exhaust ports open
+just as soon as the full force of the explosion has been spent and a
+portion of the flaming gases is discharged through the ports in the
+bottom of the cylinder. Less of the exhaust gases remains to be
+discharged through the regular exhaust member in the cylinder-head and
+this will not heat the walls of the cylinder nearly as much as the
+larger quantity of hot gas would. That the auxiliary exhaust port is of
+considerable value is conceded by many designers of fixed and fan-shaped
+air-cooled motors for airplanes.
+
+Among the advantages stated for direct air cooling, the greatest is the
+elimination of cooling water and its cooling auxiliaries, which is a
+factor of some moment, as it permits considerable reduction in
+horse-power-weight ratio of the engine, something very much to be
+desired. In the temperate zone, where the majority of airplanes are
+used, the weather conditions change in a very few months from the warm
+summer to the extreme cold winter, and when water-cooled systems are
+employed it is necessary to add some chemical substance to the water to
+prevent it from freezing. The substances commonly employed are
+glycerine, wood alcohol, or a saturated solution of calcium chloride.
+Alcohol has the disadvantage in that it vaporizes readily and must be
+often renewed. Glycerine affects the rubber hose, while the calcium
+chloride solution crystallizes and deposits salt in the radiator and
+water pipes.
+
+One of the disadvantages of an air-cooling method, as stated by those
+who do not favor this system, is that engines cooled by air cannot be
+operated for extended periods under constant load or at very high speed
+without heating up to such a point that premature ignition of the charge
+may result. The water-cooling systems, at the other hand, maintain the
+temperature of the engine more nearly constant than is possible with an
+air-cooled motor, and an engine cooled by water can be operated under
+conditions of inferior lubrication or poor mixture adjustment that would
+seriously interfere with proper and efficient cooling by air.
+
+Air-cooled motors, as a rule, use less fuel than water-cooled engines,
+because the higher temperature of the cylinder does not permit of a full
+charge of gas being inspired on the intake stroke. As special care is
+needed in operating an air-cooled engine to obtain satisfactory results
+and because of the greater difficulty which obtains in providing proper
+lubrication and fuel mixtures which will not produce undue heating, the
+air-cooled system has but few adherents at the present time, and
+practically all airplanes, with but very few exceptions, are provided
+with water-cooled power plants. Those fitted with air-cooled engines are
+usually short-flight types where maximum lightness is desired in order
+to obtain high speed and quick climb. The water-cooled engines are best
+suited for airplanes intended for long flights. The Gnome, Le Rhone and
+Clerget engines are thoroughly practical and have been widely used in
+France and England. These are rotary radial cylinder types. The Anzani
+is a fixed cylinder engine used on training machines, while the Renault
+is a V-type engine made in eight- and twelve-cylinder V forms that has
+been used on reconnaissance and bombing airplanes with success. These
+types will be fully considered in proper sequence.
+
+
+
+
+CHAPTER VIII
+
+ Methods of Cylinder Construction--Block Castings--Influence on
+ Crank-Shaft Design--Combustion Chamber Design--Bore and Stroke
+ Ratio--Meaning of Piston Speed--Advantage of Off-Set Cylinders--
+ Valve Location of Vital Import--Valve Installation Practice--
+ Valve Design and Construction--Valve Operation--Methods of
+ Driving Cam-Shaft--Valve Springs--Valve Timing--Blowing Back--
+ Lead Given Exhaust Valve--Exhaust Closing, Inlet Opening--
+ Closing the Inlet Valve--Time of Ignition--How an Engine Is
+ Timed--Gnome "Monosoupape" Valve Timing--Springless Valves--Four
+ Valves per Cylinder.
+
+
+The improvements noted in the modern internal combustion motors have
+been due to many conditions. The continual experimenting by leading
+mechanical minds could have but one ultimate result. The parts of the
+engines have been lightened and strengthened, and greater power has been
+obtained without increasing piston displacement. A careful study has
+been made of the many conditions which make for efficient motor action,
+and that the main principles are well recognized by all engineers is
+well shown by the standardization of design noted in modern power
+plants. There are many different methods of applying the same principle,
+and it will be the purpose of this chapter to define the ways in which
+the construction may be changed and still achieve the same results. The
+various components may exist in many different forms, and all have their
+advantages and disadvantages. That all methods are practical is best
+shown by the large number of successful engines which use radically
+different designs.
+
+
+METHODS OF CYLINDER CONSTRUCTION
+
+One of the most important parts of the gasoline engine and one that has
+material bearing upon its efficiency is the cylinder unit. The cylinders
+may be cast individually, or in pairs, and it is possible to make all
+cylinders a unit or block casting. Some typical methods of cylinder
+construction are shown in accompanying illustrations. The appearance of
+individual cylinder castings may be ascertained by examination of the
+Hall-Scott airplane engine. Air-cooled engine cylinders are always of
+the individual pattern.
+
+Considered from a purely theoretical point of view, the individual
+cylinder casting has much in its favor. It is advanced that more uniform
+cooling is possible than where the cylinders are cast either in pairs or
+three or four in one casting. More uniform cooling insures that the
+expansion or change of form due to heating will be more equal. This is
+an important condition because the cylinder bore must remain true under
+all conditions of operation. If the heating effect is not uniform, which
+condition is liable to obtain if metal is not evenly distributed, the
+cylinder may become distorted by heat and the bore be out of truth. When
+separate cylinders are used it is possible to make a uniform water space
+and have the cooling liquid evenly distributed around the cylinder. In
+multiple cylinder castings this is not always the rule, as in many
+instances, especially in four-cylinder block motors where compactness is
+the main feature, there is but little space between the cylinders for
+the passage of water. Under such circumstances the cooling effect is not
+even, and the stresses which obtain because of unequal expansion may
+distort the cylinder to some extent. When steel cylinders are made from
+forgings, the water jackets are usually of copper or sheet steel
+attached to the forging by autogenous welding; in the case of the latter
+and, in some cases, the former may be electro-deposited on the
+cylinders.
+
+
+BLOCK CASTINGS
+
+[Illustration: Fig. 86.--Views of Four-Cylinder Duesenberg Airplane
+Engine Cylinder Block.]
+
+The advantage of casting the cylinders in blocks is that a motor may be
+much shorter than it would be if individual castings were used. It is
+admitted that when the cylinders are cast together a more compact,
+rigid, and stronger power plant is obtained than when cast separately.
+There is a disadvantage, however, in that if one cylinder becomes
+damaged it will be necessary to replace the entire unit, which means
+scrapping three good cylinders because one of the four has failed. When
+the cylinders are cast separately one need only replace the one that has
+become damaged. The casting of four cylinders in one unit is made
+possible by improved foundry methods, and when proper provision is made
+for holding the cores when the metal is poured and the cylinder casts
+are good, the construction is one of distinct merit. It is sometimes the
+case that the proportion of sound castings is less when cylinders are
+cast in block, but if the proper precautions are observed in molding and
+the proper mixtures of cast iron used, the ratio of defective castings
+is no more than when cylinders are molded individually. As an example of
+the courage of engineers in departing from old-established rules, the
+cylinder casting shown at Fig. 86 may be considered typical. This is
+used on the Duesenberg four-cylinder sixteen-valve 4-3/4" x 7" engine
+which has a piston displacement of 496 cu. in. At a speed of 2,000
+r.p.m., corresponding to a piston speed of 2,325 ft. per min., the
+engine is guaranteed to develop 125 horse-power. The weight of the model
+engine without gear reduction is 436 lbs., but a number of refinements
+have been made in the design whereby it is expected to get the weight
+down to 390 lbs. The four cylinders are cast from semi-steel in a single
+block, with integral heads. The cylinder construction is the same as
+that which has always been used by Mr. Duesenberg, inlet and exhaust
+valves being arranged horizontally opposite each other in the head.
+There are large openings in the water jacket at both sides and at the
+ends, which are closed by means of aluminum covers, water-tightness
+being secured by the use of gaskets. This results in a saving in weight
+because the aluminum covers can be made considerably lighter than it
+would be possible to cast the jacket walls, and, besides, it permits of
+obtaining a more nearly uniform thickness of cylinder wall, as the cores
+can be much better supported. The cooling water passes completely around
+each cylinder, and there is a very considerable space between the two
+central cylinders, this being made necessary in order to get the large
+bearing area desirable for the central bearing.
+
+It is common practice to cast the water jackets integral with the
+cylinders, if cast iron or aluminum is used, and this is also the most
+economical method of applying it because it gives good results in
+practice. An important detail is that the water spaces must be
+proportioned so that they are equal around the cylinders whether these
+members are cast individually, in pairs, threes or fours. When cylinders
+are cast in block form it is good practice to leave a large opening in
+the jacket wall which will assist in supporting the core and make for
+uniform water space. It will be noticed that the casting shown at Fig.
+86 has a large opening in the side of the cylinder block. These openings
+are closed after the interior of the casting is thoroughly cleaned of
+all sand, core wire, etc., by brass, cast iron or aluminum plates. These
+also have particular value in that they may be removed after the motor
+has been in use, thus permitting one to clean out the interior of the
+water jacket and dispose of the rust, sediment, and incrustation which
+are always present after the engine has been in active service for a
+time.
+
+Among the advantages claimed for the practice of casting cylinders in
+blocks may be mentioned compactness, lightness, rigidity, simplicity of
+water piping, as well as permitting the use of simple forms of inlet and
+exhaust manifolds. The light weight is not only due to the reduction of
+the cylinder mass but because the block construction permits one to
+lighten the entire motor. The fact that all cylinders are cast together
+decreases vibration, and as the construction is very rigid, disalignment
+of working parts is practically eliminated. When inlet and exhaust
+manifolds are cored in the block casting, as is sometimes the case, but
+one joint is needed on each of these instead of the multiplicity of
+joints which obtain when the cylinders are individual castings. The
+water piping is also simplified. In the case of a four-cylinder block
+motor but two pipes are used; one for the water to enter the cylinder
+jacket, the other for the cooling liquid to discharge through.
+
+
+INFLUENCE ON CRANK-SHAFT DESIGN
+
+[Illustration: Fig. 87.--Twin-Cylinder Block of Sturtevant Airplane
+Engine is Cast of Aluminum, and Has Removable Cylinder Head.]
+
+The method of casting the cylinders has a material influence on the
+design of the crank-shaft as will be shown in proper sequence. When four
+cylinders are combined in one block it is possible to use a two-bearing
+crank-shaft. Where cylinders are cast in pairs a three-bearing
+crank-shaft is commonly supplied, and when cylinders are cast as
+individual units it is thought necessary to supply a five-bearing
+crank-shaft, though sometimes shafts having but three journals are used
+successfully. Obviously the shafts must be stronger and stiffer to
+withstand the stresses imposed if two supporting bearings are used than
+if a larger number are employed. In this connection it may be stated
+that there is less difficulty in securing alignment with a lesser number
+of bearings and there is also less friction. On the other hand, the
+greater the number of points of support a crank-shaft has the lighter
+the webs can be made and still have requisite strength.
+
+
+COMBUSTION CHAMBER DESIGN
+
+[Illustration: Fig. 88.--Aluminum Cylinder Pair Casting of Thomas 150
+Horse-Power Airplane Engine is of the L Head Type.]
+
+Another point of importance in the design of the cylinder, and one which
+has considerable influence upon the power developed, is the shape of the
+combustion chamber. The endeavor of designers is to obtain maximum power
+from a cylinder of certain proportions, and the greater energy obtained
+without increasing piston displacement or fuel consumption the higher
+the efficiency of the motor. To prevent troubles due to pre-ignition it
+is necessary that the combustion chamber be made so that there will be
+no roughness, sharp corners, or edges of metal which may remain
+incandescent when heated or which will serve to collect carbon deposits
+by providing a point of anchorage. With the object of providing an
+absolutely clean combustion chamber some makers use a separable head
+unit to their twin cylinder castings, such as shown at Fig. 87 and Fig.
+88. These permit one to machine the entire interior of the cylinder and
+combustion chamber. The relation of valve location and combustion
+chamber design will be considered in proper sequence. These cylinders
+are cast of aluminum, instead of cast iron, as is customary, and are
+provided with steel or cast iron cylinder liners forced in the soft
+metal casting bores.
+
+
+BORE AND STROKE RATIO
+
+A question that has been a vexed one and which has been the subject of
+considerable controversy is the proper proportion of the bore to the
+stroke. The early gas engines had a certain well-defined bore to stroke
+ratio, as it was usual at that time to make the stroke twice as long as
+the bore was wide, but this cannot be done when high speed is desired.
+With the development of the present-day motor the stroke or piston
+travel has been gradually shortened so that the relative proportions of
+bore and stroke have become nearly equal. Of late there seems to be a
+tendency among designers to return to the proportions which formerly
+obtained, and the stroke is sometimes one and a half or one and
+three-quarter times the bore.
+
+Engines designed for high speed should have the stroke not much longer
+than the diameter of the bore. The disadvantage of short-stroke engines
+is that they will not pull well at low speeds, though they run with
+great regularity and smoothness at high velocity. The long-stroke engine
+is much superior for slow speed work, and it will pull steadily and with
+increasing power at low speed. It was formerly thought that such engines
+should never turn more than a moderate number of revolutions, in order
+not to exceed the safe piston speed of 1,000 feet per minute. This old
+theory or rule of practice has been discarded in designing high
+efficiency automobile racing and aviation engines, and piston speeds
+from 2,500 to 3,000 feet per minute are sometimes used, though the
+average is around 2,000 feet per minute. While both short- and
+long-stroke motors have their advantages, it would seem desirable to
+average between the two. That is why a proportion of four to five or six
+seems to be more general than that of four to seven or eight, which
+would be a long-stroke ratio. Careful analysis of a number of foreign
+aviation motors shows that the average stroke is about 1.2 times the
+bore dimensions, though some instances were noted where it was as high
+as 1.7 times the bore.
+
+
+MEANING OF PISTON SPEED
+
+The factor which limits the stroke and makes the speed of rotation so
+dependent upon the travel of the piston is piston speed. Lubrication is
+the main factor which determines piston speed, and the higher the rate
+of piston travel the greater care must be taken to insure proper oiling.
+Let us fully consider what is meant by piston speed.
+
+Assume that a motor has a piston travel or stroke of six inches, for the
+sake of illustration. It would take two strokes of the piston to cover
+one foot, or twelve inches, and as there are two strokes to a revolution
+it will be seen that this permits of a normal speed of 1,000 revolutions
+per minute for an engine with a six-inch stroke, if one does not exceed
+1,000 feet per minute. If the stroke was only four inches, a normal
+speed of 1,500 revolutions per minute would be possible without
+exceeding the prescribed limit. The crank-shaft of a small engine,
+having three-inch stroke, could turn at a speed of 2,000 revolutions per
+minute without danger of exceeding the safe speed limit. It will be seen
+that the longer the stroke the slower the speed of the engine, if one
+desires to keep the piston speed within the bounds as recommended, but
+modern practice allows of greatly exceeding the speeds formerly thought
+best.
+
+
+ADVANTAGES OF OFF-SET CYLINDERS
+
+[Illustration: Fig. 90.--Cross Section of Austro-Daimler Engine, Showing
+Offset Cylinder Construction. Note Applied Water Jacket and Peculiar
+Valve Action.]
+
+Another point upon which considerable difference of opinion exists
+relates to the method of placing the cylinder upon the crank-case--i.e.,
+whether its center line should be placed directly over the center of the
+crank-shaft, or to one side of center. The motor shown at Fig. 90 is an
+off-set type, in that the center line of the cylinder is a little to
+one side of the center of the crank-shaft. Diagrams are presented at
+Fig. 91 which show the advantages of off-set crank-shaft construction.
+The view at A is a section through a simple motor with the conventional
+cylinder placing, the center line of both crank-shaft and cylinder
+coinciding. The view at B shows the cylinder placed to one side of
+center so that its center line is distinct from that of the crank-shaft
+and at some distance from it. The amount of off-set allowed is a point
+of contention, the usual amount being from fifteen to twenty-five per
+cent. of the stroke. The advantages of the off-set are shown at Fig. 91,
+C. If the crank turns in direction of the arrow there is a certain
+resistance to motion which is proportional to the amount of energy
+exerted by the engine and the resistance offered by the load. There are
+two thrusts acting against the cylinder wall to be considered, that due
+to explosion or expansion of the gas, and that which resists the motion
+of the piston. These thrusts may be represented by arrows, one which
+acts directly in a vertical direction on the piston top, the other
+along a straight line through the center of the connecting rod. Between
+these two thrusts one can draw a line representing a resultant force
+which serves to bring the piston in forcible contact with one side of
+the cylinder wall, this being known as side thrust. As shown at C, the
+crank-shaft is at 90 degrees, or about one-half stroke, and the
+connecting rod is at 20 degrees angle. The shorter connecting rod would
+increase the diagonal resultant and side thrusts, while a longer one
+would reduce the angle of the connecting rod and the side thrust of the
+piston would be less. With the off-set construction, as shown at D, it
+will be noticed that with the same connecting-rod length as shown at C
+and with the crank-shaft at 90 degrees of the circle that the
+connecting-rod angle is 14 degrees and the side thrust is reduced
+proportionately.
+
+[Illustration: Fig. 91.--Diagrams Demonstrating Advantages of Offset
+Crank-Shaft Construction.]
+
+Another important advantage is that greater efficiency is obtained from
+the explosion with an off-set crank-shaft, because the crank is already
+inclined when the piston is at top center, and all the energy imparted
+to the piston by the burning mixture can be exerted directly into
+producing a useful turning effort. When a cylinder is placed directly on
+a line with the crank-shaft, as shown at A, it will be evident that some
+of the force produced by the expansion of the gas will be exerted in a
+direct line and until the crank moves the crank throw and connecting rod
+are practically a solid member. The pressure which might be employed in
+obtaining useful turning effort is wasted by causing a direct pressure
+upon the lower half of the main bearing and the upper half of the
+crank-pin bushing.
+
+Very good and easily understood illustrations showing advantages of the
+off-set construction are shown at E and F. This is a bicycle
+crank-hanger. It is advanced that the effort of the rider is not as well
+applied when the crank is at position E as when it is at position F.
+Position E corresponds to the position of the parts when the cylinder is
+placed directly over the crank-shaft center. Position F may be compared
+to the condition which is present when the off-set cylinder construction
+is used.
+
+
+VALVE LOCATION OF VITAL IMPORT
+
+It has often been said that a chain is no stronger than its weakest
+link, and this is as true of the explosive motor as it is of any other
+piece of mechanism. Many motors which appeared to be excellently
+designed and which were well constructed did not prove satisfactory
+because some minor detail or part had not been properly considered by
+the designer. A factor having material bearing upon the efficiency of
+the internal combustion motor is the location of the valves and the
+shape of the combustion chamber which is largely influenced by their
+placing. The fundamental consideration of valve design is that the gases
+be admitted and discharged from the cylinder as quickly as possible in
+order that the speed of gas flow will not be impeded and produce back
+pressure. This is imperative in obtaining satisfactory operation in any
+form of motor. If the inlet passages are constricted the cylinder will
+not fill with explosive mixture promptly, whereas if the exhaust gases
+are not fully expelled the parts of the inert products of combustion
+retained dilute the fresh charge, making it slow burning and causing
+lost power and overheating. When an engine employs water as a cooling
+medium this substance will absorb the surplus heat readily, and the
+effects of overheating are not noticed as quickly as when air-cooled
+cylinders are employed. Valve sizes have a decided bearing upon the
+speed of motors and some valve locations permit the use of larger
+members than do other positions.
+
+While piston velocity is an important factor in determinations of power
+output, it must be considered from the aspect of the wear produced upon
+the various parts of the motor. It is evident that engines which run
+very fast, especially of high power, must be under a greater strain than
+those operating at lower speeds. The valve-operating mechanism is
+especially susceptible to the influence of rapid movement, and the
+slower the engine the longer the parts will wear and the more reliable
+the valve action.
+
+[Illustration: Fig. 92.--Diagram Showing Forms of Cylinder Demanded by
+Different Valve Placings. A--T Head Type, Valves on Opposite Sides. B--L
+Head Cylinder, Valves Side by Side. C--L Head Cylinder, One Valve in
+Head, Other in Pocket. D--Inlet Valve Over Exhaust Member, Both in Side
+Pocket. E--Valve-in-the-Head Type with Vertical Valves. F--Inclined
+Valves Placed to Open Directly into Combustion Chamber.]
+
+As will be seen by reference to the accompanying illustration, Fig. 92,
+there are many ways in which valves may be placed in the cylinder. Each
+method outlined possesses some point of advantage, because all of the
+types illustrated are used by reputable automobile manufacturers. The
+method outlined at Fig. 92, A, is widely used, and because of its shape
+the cylinder is known as the "T" form. It is approved for automobile use
+for several reasons, the most important being that large valves can be
+employed and a well-balanced and symmetrical cylinder casting obtained.
+Two independent cam-shafts are needed, one operating the inlet valves,
+the other the exhaust members. The valve-operating mechanism can be very
+simple in form, consisting of a plunger actuated by the cam which
+transmits the cam motion to the valve-stem, raising the valve as the cam
+follower rides on the point of the cam. Piping may be placed without
+crowding, and larger manifolds can be fitted than in some other
+constructions. This has special value, as it permits the use of an
+adequate discharge pipe on the exhaust side with its obvious advantages.
+This method of cylinder construction is never found on airplane engines
+because it does not permit of maximum power output.
+
+On the other hand, if considered from a viewpoint of actual heat
+efficiency, it is theoretically the worst form of combustion chamber.
+This disadvantage is probably compensated for by uniformity of expansion
+of the cylinder because of balanced design. The ignition spark-plug may
+be located directly over the inlet valve in the path of the incoming
+fresh gases, and both valves may be easily removed and inspected by
+unscrewing the valve caps without taking off the manifolds.
+
+The valve installation shown at C is somewhat unusual, though it
+provides for the use of valves of large diameter. Easy charging is
+insured because of the large inlet valve directly in the top of the
+cylinder. Conditions may be reversed if necessary, and the gases
+discharged through this large valve. Both methods are used, though it
+would seem that the free exhaust provided by allowing the gases to
+escape directly from the combustion chamber through the overhead valve
+to the exhaust manifold would make for more power. The method outlined
+at Fig. 92, F and at Fig. 90 is one that has been widely employed on
+large automobile racing motors where extreme power is required, as well
+as in engines constructed for aviation service. The inclination of the
+valves permits the use of large valves, and these open directly into the
+combustion chamber. There are no pockets to retain heat or dead gas, and
+free intake and outlet of gas is obtained. This form is quite
+satisfactory from a theoretical point of view because of the almost
+ideal combustion chamber form. Some difficulty is experienced, however,
+in properly water-jacketing the valve chamber which experience has shown
+to be necessary if the engine is to have high power.
+
+The motor shown at Fig. 92, B and Fig. 88 employs cylinders of the "L"
+type. Both valves are placed in a common extension from the combustion
+chamber, and being located side by side both are actuated from a common
+cam-shaft. The inlet and exhaust pipes may be placed on the same side of
+the engine and a very compact assemblage is obtained, though this is
+optional if passages are cored in the cylinder pairs to lead the gases
+to opposite sides. The valves may be easily removed if desired, and the
+construction is fairly good from the viewpoint of both foundry man and
+machinist. The chief disadvantage is the limited area of the valves and
+the loss of heat efficiency due to the pocket. This form of combustion
+chamber, however, is more efficient than the "T" head construction,
+though with the latter the use of larger valves probably compensates for
+the greater heat loss. It has been stated as an advantage of this
+construction that both manifolds can be placed at the same side of the
+engine and a compact assembly secured. On the other hand, the
+disadvantage may be cited that in order to put both pipes on the same
+side they must be of smaller size than can be used when the valves are
+oppositely placed. The "L" form cylinder is sometimes made more
+efficient if but one valve is placed in the pocket while the other is
+placed over it. This construction is well shown at Fig. 92, D and is
+found on Anzani motors.
+
+[Illustration: Fig. 93.--Sectional View of Engine Cylinder Showing Valve
+and Cage Installation.]
+
+The method of valve application shown at Fig. 87 is an ingenious method
+of overcoming some of the disadvantages inherent with valve-in-the-head
+motors. In the first place it is possible to water-jacket the valves
+thoroughly, which is difficult to accomplish when they are mounted in
+cages. The water circulates directly around the walls of the valve
+chambers, which is superior to a construction where separate cages are
+used, as there are two thicknesses of metal with the latter, that of the
+valve-cage proper and the wall of the cylinder. The cooling medium is in
+contact only with the outer wall, and as there is always a loss of heat
+conductivity at a joint it is practically impossible to keep the
+exhaust valves and their seats at a uniform temperature. The valves may
+be of larger size without the use of pockets when seating directly in
+the head. In fact, they could be equal in diameter to almost half the
+bore of the cylinder, which provides an ideal condition of charge
+placement and exhaust. When valve grinding is necessary the entire head
+is easily removed by taking off six nuts and loosening inlet manifold
+connections, which operation would be necessary even if cages were
+employed, as in the engine shown at Fig. 93.
+
+[Illustration: Fig. 94.--Diagrams Showing How Gas Enters Cylinder
+Through Overhead Valves and Other Types. A--Tee Head Cylinder. B--L Head
+Cylinder. C--Overhead Valve.]
+
+[Illustration: Fig. 95.--Conventional Methods of Operating Internal
+Combustion Motor Valves.]
+
+At Fig. 94, A and B, a section through a typical "L"-shaped cylinder is
+depicted. It will be evident that where a pocket construction is
+employed, in addition to its faculty for absorbing heat, the passage of
+gas would be impeded. For example, the inlet gas rushing in through the
+open valve would impinge sharply upon the valve-cap or combustion head
+directly over the valve and then must turn at a sharp angle to enter the
+combustion chamber and then at another sharp angle to fill the
+cylinders. The same conditions apply to the exhaust gases, though they
+are reversed. When the valve-in-the-head type of cylinder is employed,
+as at C, the only resistance offered the gas is in the manifold. As far
+as the passage of the gases in and out of the cylinder is concerned,
+ideal conditions obtain. It is claimed that valve-in-the-head motors are
+more flexible and responsive than other forms, but the construction has
+the disadvantage in that the valves must be opened through a rather
+complicated system of push rods and rocker arms instead of the simpler
+and direct plunger which can be used with either the "T" or "L" head
+cylinders. This is clearly outlined in the illustrations at Fig. 95,
+where A shows the valve in the head-operating mechanism necessary if the
+cam-shaft is carried at the cylinder base, while B shows the most direct
+push-rod action obtained with "T" or "L" head cylinder placing.
+
+[Illustration: Fig. 96.--Examples of Direct Valve Actuation by Overhead
+Cam-Shaft. A--Mercedes. B--Hall-Scott. C--Wisconsin.]
+
+[Illustration: Fig. 97.
+
+CENSORED]
+
+[Illustration: Fig. 98.
+
+CENSORED]
+
+The objection can be easily met by carrying the cam-shaft above the
+cylinders and driving it by means of gearing. The types of engine
+cylinders using this construction are shown at Fig. 96, and it will be
+evident that a positive and direct valve action is possible by following
+the construction originated by the Mercedes (German) aviation engine
+designers and outlined at A. The other forms at B and C are very clearly
+adaptations of this design. The Hall-Scott engine at Fig. 97 is depicted
+in part section and no trouble will be experienced in understanding the
+bevel pinion and gear drive from the crank-shaft to the overhead
+cam-shaft through a vertical counter-shaft. A very direct valve action
+is used in the Duesenberg engines, one of which is shown in part section
+at Fig. 98. The valves are parallel with the piston top and are actuated
+by rocker arms, one end of which bears against the valve stem, and the
+other rides the cam-shaft.
+
+[Illustration: Fig. 99.--Sectional Views Showing Arrangement of Novel
+Concentric Valve Arrangement Devised by Panhard for Aerial Engines.]
+
+The form shown at Fig. 99 shows an ingenious application of the
+valve-in-the-head idea which permits one to obtain large valves. It has
+been used on some of the Panhard aviation engines and on the American
+Aeromarine power plants. The inlet passage is controlled by the sliding
+sleeve which is hollow and slotted so as to permit the inlet gases to
+enter the cylinder through the regular type poppet valve which seats in
+the exhaust sleeve. When the exhaust valve is operated by the tappet rod
+and rocker arm the intake valve is also carried down with it. The
+intake gas passage is closed, however, and the burned gases are
+discharged through the large annular passage surrounding the sleeve.
+When the inlet valve leaves its seat in the sleeve the passage of cool
+gas around the sleeve keeps the temperature of both valves to a low
+point and the danger of warping is minimized. A dome-shaped combustion
+chamber may be used, which is an ideal form in conserving heat
+efficiency, and as large valves may be installed the flow of both fresh
+and exhaust gases may be obtained with minimum resistance. The intake
+valve is opened by a small auxiliary rocker arm which is lifted when the
+cam follower rides into the depression in the cam by the action of the
+strong spring around the push rod. When the cam follower rides on the
+high point the exhaust sleeve is depressed from its seat against the
+cylinder. By using a cam having both positive and negative profiles, a
+single rod suffices for both valves because of its push and pull action.
+
+
+VALVE DESIGN AND CONSTRUCTION
+
+Valve dimensions are an important detail to be considered and can be
+determined by several conditions, among which may be cited method of
+installation, operating mechanism, material employed, engine speed
+desired, manner of cylinder cooling and degree of lift desired. A review
+of various methods of valve location has shown that when the valves are
+placed directly in the head we can obtain the ideal cylinder form,
+though larger valves may be used if housed in a separate pocket, as
+afforded by the "T" head construction. The method of operation has much
+to do with the size of the valves. For example, if an automatic inlet
+valve is employed it is good practice to limit the lift and obtain the
+required area of port opening by augmenting the diameter. Because of
+this a valve of the automatic type is usually made twenty per cent.
+larger than one mechanically operated. When both are actuated by cam
+mechanism, as is now common practice, they are usually made the same
+size and are interchangeable, which greatly simplifies manufacture. The
+relation of valve diameter to cylinder bore is one that has been
+discussed for some time by engineers. The writer's experience would
+indicate that they should be at least half the bore, if possible. While
+the mushroom type or poppet valve has become standard and is the most
+widely used form at the present time, there is some difference of
+opinion among designers as to the materials employed and the angle of
+the seat. Most valves have a bevel seat, though some have a flat
+seating. The flat seat valve has the distinctive advantage of providing
+a clear opening with lesser lift, this conducing to free gas flow. It
+also has value because it is silent in operation, but the disadvantage
+is present that best material and workmanship must be used in their
+construction to obtain satisfactory results. As it can be made very
+light it is particularly well adapted for use as an automatic inlet
+valve. Among other disadvantages cited is the claim that it is more
+susceptible to derangement, owing to the particles of foreign matter
+getting under the seat. With a bevel seat it is argued that the foreign
+matter would be more easily dislodged by the gas flow, and that the
+valve would close tighter because it is drawn positively against the
+bevel seat.
+
+Several methods of valve construction are the vogue, the most popular
+form being the one-piece type; those which are composed of a head of one
+material and stem of another are seldom used in airplane engines because
+they are not reliable. In the built-up construction the head is usually
+of high nickel steel or cast iron, which metals possess good
+heat-resisting qualities. Heads made of these materials are not likely
+to warp, scale, or pit, as is sometimes the case when ordinary grades of
+machinery steel are used. The cast-iron head construction is not popular
+because it is often difficult to keep the head tight on the stem. There
+is a slight difference in expansion ratio between the head and the stem,
+and as the stem is either screwed or riveted to the cast-iron head the
+constant hammering of the valve against its seat may loosen the joint.
+As soon as the head is loose on the stem the action of the valve becomes
+erratic. The best practice is to machine the valves from tungsten steel
+forgings. This material has splendid heat-resisting qualities and will
+not pit or become scored easily. Even the electrically welded head to
+stem types which are used in automobile engines are not looked upon with
+favor in the aviation engine. Valve stem guides and valve stems must be
+machined very accurately to insure correct action. The usual practice in
+automobile engines is shown at Fig. 100.
+
+[Illustration: Fig. 100.--Showing Clearance Allowed Between Valve Stem
+and Valve Stem Guide to Secure Free Action.]
+
+
+VALVE OPERATION
+
+The methods of valve operation commonly used vary according to the type
+of cylinder construction employed. In all cases the valves are lifted
+from their seats by cam-actuated mechanism. Various forms of
+valve-lifting cams are shown at Fig. 101. As will be seen, a cam
+consists of a circle to which a raised, approximately triangular member
+has been added at one point. When the cam follower rides on the circle,
+as shown at Fig. 102, there is no difference in height between the cam
+center and its periphery and there is no movement of the plunger. As
+soon as the raised portion of the cam strikes the plunger it will lift
+it, and this reciprocating movement is transmitted to the valve stem by
+suitable mechanical connections.
+
+[Illustration: Fig. 101.--Forms of Valve-Lifting Cams Generally
+Employed. A--Cam Profile for Long Dwell and Quick Lift. B--Typical Inlet
+Cam Used with Mushroom Type Follower. C--Average Form of Cam.
+D--Designed to Give Quick Lift and Gradual Closing.]
+
+The cam forms outlined at Fig. 101 are those commonly used. That at A is
+used on engines where it is desired to obtain a quick lift and to keep
+the valve fully opened as long as possible. It is a noisy form, however,
+and is not very widely employed. That at B is utilized more often as an
+inlet cam while the profile shown at C is generally depended on to
+operate exhaust valves. The cam shown at D is a composite form which has
+some of the features of the other three types. It will give the quick
+opening of form A, the gradual closing of form B, and the time of
+maximum valve opening provided by cam profile C.
+
+[Illustration: Fig. 102.--Showing Principal Types of Cam Followers which
+Have Received General Application.]
+
+The various types of valve plungers used are shown at Fig. 102. That
+shown at A is the simplest form, consisting of a simple cylindrical
+member having a rounded end which follows the cam profile. These are
+sometimes made of square stock or kept from rotating by means of a key
+or pin. A line contact is possible when the plunger is kept from
+turning, whereas but a single point bearing is obtained when the plunger
+is cylindrical and free to revolve. The plunger shown at A will follow
+only cam profiles which have gradual lifts. The plunger shown at B is
+left free to revolve in the guide bushing and is provided with a flat
+mushroom head which serves as a cam follower. The type shown at C
+carries a roller at its lower end and may follow very irregular cam
+profiles if abrupt lifts are desired. While forms A and B are the
+simplest, that outlined at C in its various forms is more widely used.
+Compound plungers are used on the Curtiss OX-2 motors, one inside the
+other. The small or inner one works on a cam of conventional design, the
+outer plunger follows a profile having a flat spot to permit of a pull
+rod action instead of a push rod action. All the methods in which levers
+are used to operate valves are more or less noisy because clearance must
+be left between the valve stem and the stop of the plunger. The space
+must be taken up before the valve will leave its seat, and when the
+engine is operated at high speeds the forcible contact between the
+plunger and valve stem produces a rattling sound until the valves become
+heated and expand and the stems lengthen out. Clearance must be left
+between the valve stems and actuating means. This clearance is clearly
+shown in Fig. 103 and should be .020" (twenty thousandths) when engine
+is cold. The amount of clearance allowed depends entirely upon the
+design of the engine and length of valve stem. On the Curtiss OX-2
+engines the clearance is but .010" (ten thousandths) because the valve
+stems are shorter. Too little clearance will result in loss of power or
+misfiring when engine is hot. Too much clearance will not allow the
+valve to open its full amount and will disturb the timing.
+
+[Illustration: Fig. 103.--Diagram Showing Proper Clearance to Allow
+Between Adjusting Screw and Valve Stems in Hall-Scott Aviation Engines.]
+
+
+METHODS OF DRIVING CAM-SHAFT
+
+Two systems of cam-shaft operation are used. The most common of these is
+by means of gearing of some form. If the cam-shaft is at right angles to
+the crank-shaft it may be driven by worm, spiral, or bevel gearing. If
+the cam-shaft is parallel to the crank-shaft, simple spur gear or chain
+connection may be used to turn it. A typical cam-shaft for an
+eight-cylinder V engine is shown at Fig. 104. It will be seen that the
+sixteen cams are forged integrally with the shaft and that it is
+spur-gear driven. The cam-shaft drive of the Hall-Scott motor is shown
+at Fig. 97.
+
+[Illustration: Fig. 104.--Cam-Shaft of Thomas Airplane Motor Has Cams
+Forged Integral. Note Split Cam-Shaft Bearings and Method of Gear
+Retention.]
+
+While gearing is more commonly used, considerable attention has been
+directed of late to silent chains for cam-shaft operation. The ordinary
+forms of block or roller chain have not proven successful in this
+application, but the silent chain, which is in reality a link belt
+operating over toothed pulleys, has demonstrated its worth. The tendency
+to its use is more noted on foreign motors than those of American
+design. It first came to public notice when employed on the
+Daimler-Knight engine for driving the small auxiliary crank-shafts which
+reciprocated the sleeve valves. The advantages cited for the application
+of chains are, first, silent operation, which obtains even after the
+chains have worn considerably; second, in designing it is not necessary
+to figure on maintaining certain absolute center distances between the
+crank-shaft and cam-shaft sprockets, as would be the case if
+conventional forms of gearing were used. On some forms of motor
+employing gears, three and even four members are needed to turn the
+cam-shaft. With a chain drive but two sprockets are necessary, the chain
+forming a flexible connection which permits the driving and driven
+members to be placed at any distance apart that the exigencies of the
+design demand. When chains are used it is advised that some means for
+compensating chain slack be provided, or the valve timing will lag when
+chains are worn. Many combination drives may be worked out with chains
+that would not be possible with other forms of gearing. Direct gear
+drive is favored at the present time by airplane engine designers
+because they are the most certain and positive means, even when a number
+of gears must be used as intermediate drive members. With overhead
+cam-shafts, bevel gears work out very well in practice, as in the
+Hall-Scott motors and others of that type.
+
+
+VALVE SPRINGS
+
+[Illustration: Fig. 105.--Section Through Cylinder of Knight Motor,
+Showing Important Parts of Valve Motion.]
+
+Another consideration of importance is the use of proper valve-springs,
+and particular care should be taken with those, of automatic valves. The
+spring must be weak enough to allow the valve to open when the suction
+is light, and must be of sufficient strength to close it in time at high
+speeds. It should be made as large as possible in diameter and with a
+large number of convolutions, in order that fatigue of the metal be
+obviated, and it is imperative that all springs be of the same strength
+when used on a multiple-cylinder engine. Practically all valves used to
+control the gas flow in airplane engines are mechanically operated. On
+the exhaust valve the spring must be strong enough so that the valve
+will not be sucked in on the inlet stroke. It should be borne in mind
+that if the spring is too strong a strain will be imposed on the
+valve-operating mechanism, and a hammering action produced which may
+cause deformation of the valve-seat. Only pressure enough to insure that
+the operating mechanism will follow the cam is required. It is common
+practice to make the inlet and exhaust valve springs of the same
+tension when the valves are of the same size and both mechanically
+operated. This is done merely to simplify manufacture and not because it
+is necessary for the inlet valve-spring to be as strong as the other.
+Valve springs of the helical coil type are generally used, though
+torsion or "scissors" springs and laminated or single-leaf springs are
+also utilized in special applications. Two springs are used on each
+valve in some valve-in-the-head types; a spring of small pitch diameter
+inside the regular valve-spring and concentric with it. Its function is
+to keep the valve from falling into the cylinder in event of breakage of
+the main spring in some cases, and to provide a stronger return action
+in others.
+
+[Illustration: Fig. 106.--Diagrams Showing Knight Sleeve Valve Action.]
+
+
+KNIGHT SLIDE VALVE MOTOR
+
+The sectional view through the cylinder at Fig. 105 shows the Knight
+sliding sleeves and their actuating means very clearly. The diagrams at
+Fig. 106 show graphically the sleeve movements and their relation to the
+crank-shaft and piston travel. The action may be summed up as follows:
+The inlet port begins to open when the lower edge of the opening of the
+outside sleeve which is moving down passes the top of the slot in the
+inner member also moving downwardly. The inlet port is closed when the
+lower edge of the slot in the inner sleeve which is moving up passes the
+top edge of the port in the outer sleeve which is also moving toward the
+top of the cylinder. The inlet opening extends over two hundred degrees
+of crank motion. The exhaust port is uncovered slightly when the lower
+edge of the port in the inner sleeve which is moving down passes the
+lower edge of the portion of the cylinder head which protrudes in the
+cylinder. When the top of the port in the outer sleeve traveling toward
+the bottom of the cylinder passes the lower edge of the slot in the
+cylinder wall the exhaust passage is closed. The exhaust opening extends
+over a period corresponding to about two hundred and forty degrees of
+crank motion. The Knight motor has not been applied to aircraft to the
+writer's knowledge, but an eight-cylinder Vee design that might be
+useful in that connection if lightened is shown at Fig. 107. The main
+object is to show that the Knight valve action is the only other besides
+the mushroom or poppet valve that has been applied successfully to high
+speed gasoline engines.
+
+
+VALVE TIMING
+
+It is in valve timing that the greatest difference of opinion prevails
+among engineers, and it is rare that one will see the same formula in
+different motors. It is true that the same timing could not be used with
+motors of different construction, as there are many factors which
+determine the amount of lead to be given to the valves. The most
+important of these is the relative size of the valve to the cylinder
+bore, the speed of rotation it is desired to obtain, the fuel
+efficiency, the location of the valves, and other factors too numerous
+to mention.
+
+[Illustration: Fig. 107.--Cross Sectional View of Knight Type Eight
+Cylinder V Engine.]
+
+Most of the readers should be familiar with the cycle of operation of
+the internal combustion motor of the four-stroke type, and it seems
+unnecessary to go into detail except to present a review. The first
+stroke of the piston is one in which a charge of gas is taken into the
+motor; the second stroke, which is in reverse direction to the first, is
+a compression stroke, at the end of which the spark takes place,
+exploding the charge and driving the piston down on the third or
+expansion stroke, which is in the same direction as the intake stroke,
+and finally, after the piston has nearly reached the end of this stroke,
+another valve opens to allow the burned gases to escape, and remains
+open until the piston has reached the end of the fourth stroke and is in
+a position to begin the series over again. The ends of the strokes are
+reached when the piston comes to a stop at either top or bottom of the
+cylinder and reverses its motion. That point is known as a center, and
+there are two for each cylinder, top and bottom centers, respectively.
+
+All circles may be divided into 360 parts, each of which is known as a
+degree, and, in turn, each of these degrees may be again divided into
+minutes and seconds, though we need not concern ourselves with anything
+less than the degree. Each stroke of the piston represents 180 degrees
+travel of the crank, because two strokes represent one complete
+revolution of three hundred and sixty degrees. The top and bottom
+centers are therefore separated by 180 degrees. Theoretically each phase
+of a four-cycle engine begins and ends at a center, though in actual
+practice the inertia or movement of the gases makes it necessary to
+allow a lead or lag to the valve, as the case may be. If a valve opens
+before a center, the distance is called "lead"; if it closes after a
+center, this distance is known as "lag." The profile of the cams
+ordinarily used to open or close the valves represents a considerable
+time in relation to the 180 degrees of the crank-shaft travel, and the
+area of the passages through which the gases are admitted or exhausted
+is quite small owing to the necessity of having to open or close the
+valves at stated times; therefore, to open an adequately large passage
+for the gases it is necessary to open the valves earlier and close them
+later than at centers.
+
+That advancing the opening of the exhaust valve was of value was
+discovered on the early motors and is explained by the necessity of
+releasing a large amount of gas, the volume of which has been greatly
+raised by the heat of combustion. When the inlet valves were
+mechanically operated it was found that allowing them to lag at closing
+enabled the inspiration of a greater volume of gas. Disregarding the
+inertia or flow of the gases, opening the exhaust at center would enable
+one to obtain full value of the expanding gases the entire length of the
+piston stroke, and it would not be necessary to keep the valve open
+after the top center, as the reverse stroke would produce a suction
+effect which might draw some of the inert charge back into the cylinder.
+On the other hand, giving full consideration to the inertia of the gas,
+opening the valve before center is reached will provide for quick
+expulsion of the gases, which have sufficient velocity at the end of the
+stroke, so that if the valve is allowed to remain open a little longer,
+the amount of lag varying with the opinions of the designer, the
+cylinder is cleared in a more thorough manner.
+
+
+BLOWING BACK
+
+When the factor of retarded opening is considered without reckoning the
+inertia of the gases, it would appear that if the valve were allowed to
+remain open after center had passed, say, on the closing of the inlet,
+the piston, having reversed its motion, would have the effect of
+expelling part of the fresh charge through the still open valve as it
+passed inward at its compression stroke. This effect is called blowing
+back, and is often noted with motors where the valve settings are not
+absolutely correct, or where the valve-springs or seats are defective
+and prevent proper closing.
+
+This factor is not of as much import as might appear, as on closer
+consideration it will be seen that the movement of the piston as the
+crank reaches either end of the stroke is less per degree of angular
+movement than it is when the angle of the connecting rod is greater.
+Then, again, a certain length of time is required for the reversal of
+motion of the piston, during which time the crank is in motion but the
+piston practically at a standstill. If the valves are allowed to remain
+open during this period, the passage of the gas in or out of the
+cylinder will be by its own momentum.
+
+
+LEAD GIVEN EXHAUST VALVE
+
+The faster a motor turns, all other things being equal, the greater the
+amount of lead or advance it is necessary to give the opening of the
+exhaust valve. It is self-evident truth that if the speed of a motor is
+doubled it travels twice as many degrees in the time necessary to lower
+the pressure. As most designers are cognizant of this fact, the valves
+are proportioned accordingly. It is well to consider in this respect
+that the cam profile has much to do with the manner in which the valve
+is opened; that is, the lift may be abrupt and the gas allowed to escape
+in a body, or the opening may be gradual, the gas issuing from the
+cylinder in thin streams. An analogy may be made with the opening of any
+bottle which contains liquid highly carbonated. If the cork is removed
+suddenly the gas escapes with a loud pop, but, on the other hand, if the
+bottle is uncorked gradually, the gas escapes from the receptacle in
+thin streams around the cork, and passage of the gases to the air is
+accomplished without noise. While the second plan is not harsh, it is
+slower than the former, as must be evident.
+
+
+EXHAUST CLOSING, INLET OPENING
+
+A point which has been much discussed by engineers is the proper
+relation of the closing of the exhaust valve and the opening of the
+inlet. Theoretically they should succeed each other, the exhaust closing
+at upper dead center and the inlet opening immediately afterward. The
+reason why a certain amount of lag is given the exhaust closing in
+practice is that the piston cannot drive the gases out of the cylinder
+unless they are compressed to a degree in excess of that existing in the
+manifold or passages, and while toward the end of the stroke this
+pressure may be feeble, it is nevertheless indispensable. At the end of
+the piston's stroke, as marked by the upper dead center, this
+compression still exists, no matter how little it may be, so that if the
+exhaust valve is closed and the inlet opened immediately afterward, the
+pressure which exists in the cylinder may retard the entrance of the
+fresh gas and a certain portion of the inert gas may penetrate into the
+manifold. As the piston immediately begins to aspirate, this may not be
+serious, but as these gases are drawn back into the cylinder the fresh
+charge will be diluted and weakened in value. If the spark-plug is in a
+pocket, the points may be surrounded by this weak gas, and the explosion
+will not be nearly as energetic as when the ignition spark takes place
+in pure mixture.
+
+It is a well-known fact that the exhaust valve should close after dead
+center and that a certain amount of lag should be given to opening of
+the inlet. The lag given the closing of the exhaust valve should not be
+as great as that given the closing of the inlet valve. Assuming that the
+excess pressure of the exhaust will equal the depression during
+aspiration, the time necessary to complete the emptying of the cylinder
+will be proportional to the volume of the gas within it. At the end of
+the suction stroke the volume of gas contained in the cylinder is equal
+to the cylindrical volume plus the space of the combustion chamber. At
+the end of the exhaust stroke the volume is but that of the dead space,
+and from one-third to one-fifth its volume before compression. While it
+is natural to assume that this excess of burned gas will escape faster
+than the fresh gas will enter the cylinder, it will be seen that if the
+inlet valve were allowed to lag twenty degrees, the exhaust valve lag
+need not be more than five degrees, providing that the capacity of the
+combustion chamber was such that the gases occupied one-quarter of their
+former volume.
+
+It is evident that no absolute rule can be given, as back pressure will
+vary with the design of the valve passages, the manifolds, and the
+construction of the muffler. The more direct the opening, the sooner the
+valve can be closed and the better the cylinder cleared. Ten degrees
+represent an appreciable angle of the crank, and the time required for
+the crank to cover this angular motion is not inconsiderable and an
+important quantity of the exhaust may escape, but the piston is very
+close to the dead center after the distance has been covered.
+
+Before the inlet valve opens there should be a certain depression in the
+cylinder, and considerable lag may be allowed before the depression is
+appreciable. So far as the volume of fresh gas introduced during the
+admission stroke is concerned, this is determined by the displacement of
+the piston between the point where the inlet valve opens and the point
+of closing, assuming that sufficient gas has been inspired so that an
+equilibrium of pressure has been established between the interior of the
+cylinder and the outer air. The point of inlet opening varies with
+different motors. It would appear that a fair amount of lag would be
+fifteen degrees past top center for the inlet opening, as a certain
+depression will exist in the cylinder, assuming that the exhaust valve
+has closed five or ten degrees after center, and at the same time the
+piston has not gone down far enough on its stroke to materially decrease
+the amount of gas which will be taken into the cylinder.
+
+
+CLOSING THE INLET VALVE
+
+As in the case with the other points of opening and closing, there is a
+wide diversity of practice as relates to closing the inlet valve. Some
+of the designers close this exactly at bottom center, but this practice
+cannot be commended, as there is a considerable portion of time, at
+least ten or fifteen degrees angular motion of the crank, before the
+piston will commence to travel to any extent on its compression stroke.
+The gases rushing into the cylinder have considerable velocity, and
+unless an equilibrium is obtained between the pressure inside and that
+of the atmosphere outside, they will continue to rush into the cylinder
+even after the piston ceases to exert any suction effect.
+
+For this reason, if the valve is closed exactly on center, a full charge
+may not be inspired into the cylinder, though if the time of closing is
+delayed, this momentum or inertia of the gas will be enough to insure
+that a maximum charge is taken into the cylinder. The writer considers
+that nothing will be gained if the valve is allowed to remain open
+longer than twenty degrees, and an analysis of practice in this respect
+would seem to confirm this opinion. From that point in the crank
+movement the piston travel increases and the compressive effect is
+appreciable, and it would appear that a considerable proportion of the
+charge might be exhausted into the manifold and carburetor if the valve
+were allowed to remain open beyond a point corresponding to twenty
+degrees angular movement of the crank.
+
+
+TIME OF IGNITION
+
+In this country engineers unite in providing a variable time of
+ignition, though abroad some difference of opinion is noted on this
+point. The practice of advancing the time of ignition, when affected
+electrically, was severely condemned by early makers, these maintaining
+that it was necessary because of insufficient heat and volume of the
+spark, and it was thought that advancing ignition was injurious. The
+engineers of to-day appreciate the fact that the heat of the electric
+spark, especially when from a mechanical generator of electrical energy,
+is the only means by which we can obtain practically instantaneous
+explosion, as required by the operation of motors at high speeds, and
+for the combustion of large volumes of gas.
+
+[Illustration: Fig. 108.--Diagrams Explaining Valve and Ignition Timing
+of Hall-Scott Aviation Engine.]
+
+It is apparent that a motor with a fixed point of ignition is not as
+desirable, in every way, as one in which the ignition can be advanced to
+best meet different requirements, and the writer does not readily
+perceive any advantage outside of simplicity of control in establishing
+a fixed point of ignition. In fact, there seems to be some difference of
+opinion among those designers who favor fixed ignition, and in one case
+this is located forty-three degrees ahead of center, and in another
+motor the point is fixed at twenty degrees, so that it may be said that
+this will vary as much as one hundred per cent. in various forms. This
+point will vary with different methods of ignition, as well as the
+location of the spark-plug or igniter. For the sake of simplicity, most
+airplane engines use set spark; if an advancing and retarding mechanism
+is fitted, it is only to facilitate starting, as the spark is kept
+advanced while in flight, and control is by throttle alone.
+
+[Illustration: Fig. 109.--Timing Diagram of Typical Six-Cylinder
+Engine.]
+
+It is obvious by consideration of the foregoing that there can be no
+arbitrary rules established for timing, because of the many conditions
+which determine the best times for opening and closing the valves. It is
+customary to try various settings when a new motor is designed until the
+most satisfactory points are determined, and the setting which will be
+very suitable for one motor is not always right for one of different
+design. The timing diagram shown at Fig. 108 applies to the Hall-Scott
+engine, and may be considered typical. It should be easily followed in
+view of the very complete explanation given in preceding pages. Another
+six-cylinder engine diagram is shown at Fig. 109, and an eight-cylinder
+timing diagram is shown at Fig. 110. In timing automobile engines no
+trouble is experienced, because timing marks are always indicated on
+the engine fly-wheel register with an indicating trammel on the
+crank-case. To time an airplane engine accurately, as is necessary to
+test for a suspected cam-shaft defect, a timing disc of aluminum is
+attached to the crank-shaft which has the timing marks indicated
+thereon. If the disc is made 10 or 12 inches in diameter, it may be
+divided into degrees without difficulty.
+
+[Illustration: Fig. 110.--Timing Diagram of Typical Eight-Cylinder V
+Engine.]
+
+
+HOW AN ENGINE IS TIMED
+
+In timing a motor from the marks on the timing disc rim it is necessary
+to regulate the valves of but one cylinder at a time. Assuming that the
+disc is revolving in the direction of engine rotation, and that the
+firing order of the cylinders is 1-3-4-2, the operation of timing would
+be carried on as follows: The crank-shaft would be revolved until the
+line marked "Exhaust opens 1 and 4" registered with the trammel on the
+motor bed. At this point the exhaust-valve of either cylinder No. 1 or
+No. 4 should begin to open. This can be easily determined by noting
+which of these cylinders holds the compressed charge ready for ignition.
+Assuming that the spark has occurred in cylinder No. 1, then when the
+fly-wheel is turned from the position to that in which the line marked
+"Exhaust opens 1 and 4" coincides with the trammel point, the
+valve-plunger under the exhaust-valve of cylinder No. 1 should be
+adjusted in such a way that there is no clearance between it and the
+valve stem. Further movement of the wheel in the same direction should
+produce a lift of the exhaust valve. The disc is turned about two
+hundred and twenty-five degrees, or a little less than three-quarters of
+a revolution; then the line marked "Exhaust closes 1 and 4" will
+register with the trammel point. At this period the valve-plunger and
+the valve-stem should separate and a certain amount of clearance obtain
+between them. The next cylinder to time would be No. 3. The crank-shaft
+is rotated until mark "Exhaust opens 2 and 3" comes in line with the
+trammel. At this point the exhaust valve of cylinder No. 3 should be
+just about opening. The closing is determined by rotating the shaft
+until the line "Exhaust closes 2 and 3" comes under the trammel.
+
+This operation is carried on with all the cylinders, it being well to
+remember that but one cylinder is working at a time and that a
+half-revolution of the fly-wheel corresponds to a full working stroke of
+all the cylinders, and that while one is exhausting the others are
+respectively taking in a new charge, compressing and exploding. For
+instance, if cylinder No. 1 has just completed its power-stroke, the
+piston in cylinder No. 3 has reached the point where the gas may be
+ignited to advantage. The piston of cylinder No. 4, which is next to
+fire, is at the bottom of its stroke and will have inspired a charge,
+while cylinder No. 2, which is the last to fire, will have just finished
+expelling a charge of burned gas, and will be starting the intake
+stroke. This timing relates to a four-cylinder engine in order to
+simplify the explanation. The timing instructions given apply only to
+the conventional motor types. Rotary cylinder engines, especially the
+Gnome "monosoupape," have a distinctive valve timing on account of the
+peculiarities of design.
+
+
+GNOME "MONOSOUPAPE" VALVE TIMING
+
+In the present design of the Gnome motor, a cycle of operations somewhat
+different from that employed in the ordinary four-cycle engine is made
+use of, says a writer in "The Automobile," in describing the action of
+this power-plant. This cycle does away with the need for the usual inlet
+valve and makes the engine operable with only a single valve, hence the
+name _monosoupape_, or "single-valve." The cycle is as follows: A charge
+being compressed in the outer end of the cylinder or combustion chamber,
+it is ignited by a spark produced by the spark-plug located in the side
+of this chamber, and the burning charge expands as the piston moves down
+in the cylinder while the latter revolves around the crank-shaft. When
+the piston is about half-way down on the power stroke, the exhaust
+valve, which is located in the center of the cylinder-head, is
+mechanically opened, and during the following upstroke of the piston the
+burnt gases are expelled from the cylinder through the exhaust valve
+directly into the atmosphere.
+
+Instead of closing at the end of the exhaust stroke, or a few degrees
+thereafter, the exhaust valve is held open for about two-thirds of the
+following inlet stroke of the piston, with the result that fresh air is
+drawn through the exhaust valve into the cylinder. When the cylinder is
+still 65 degrees from the end of the inlet half-revolution, the exhaust
+valve closes. As no more air can get into the cylinder, and as the
+piston continues to move inwardly, it is obvious that a partial vacuum
+is formed.
+
+When the cylinder approaches within 20 degrees of the end of the inlet
+half-revolution a series of small inlet ports all around the
+circumference of the cylinder wall is uncovered by the top edge of the
+piston, whereby the combustion chamber is placed in communication with
+the crank chamber. As the pressure in the crank chamber is substantially
+atmospheric and that in the combustion chamber is below atmospheric,
+there results a suction effect which causes the air from the crank
+chamber to flow into the combustion chamber. The air in the crank
+chamber is heavily charged with gasoline vapor, which is due to the fact
+that a spray nozzle connected with the gasoline supply tank is located
+inside the chamber. The proportion of gasoline vapor in the air in the
+crank chamber is several times as great as in the ordinary combustible
+mixture drawn from a carburetor into the cylinder. This extra-rich
+mixture is diluted in the combustion chamber with the air which entered
+it through the exhaust valve during the first part of the inlet stroke,
+thus forming a mixture of the proper proportion for complete combustion.
+
+The inlet ports in the cylinder wall remain open until 20 degrees of
+the compression half-revolution has been completed, and from that moment
+to near the end of the compression stroke the gases are compressed in
+the cylinder. Near the end of the stroke ignition takes place and this
+completes the cycle.
+
+The exact timing of the different phases of the cycle is shown in the
+diagram at Fig. 111. It will be seen that ignition occurs substantially
+20 degrees ahead of the outer dead center, and expansion of the burning
+gases continues until 85 degrees past the outer dead center, when the
+piston is a little past half-stroke. Then the exhaust-valve opens and
+remains open for somewhat more than a complete revolution of the
+cylinders, or, to be exact, for 390 degrees of cylinder travel, until
+115 degrees past the top dead center on the second revolution. Then for
+45 degrees of travel the charge within the cylinder is expanded,
+whereupon the inlet ports are uncovered and remain open for 40 degrees
+of cylinder travel, 20 degrees on each side of the inward dead center
+position.
+
+
+SPRINGLESS VALVES
+
+Springless valves are the latest development on French racing car
+engines, and it is possible that the positively-operated types will be
+introduced on aviation engines also. Two makes of positively-actuated
+valves are shown at Fig. 112. The positive-valve motor differs from the
+conventional form by having no necessity for valve-springs, as a cam not
+only assures the opening of the valve, but also causes it to return to
+the valve-seat. In this respect it is much like the sleeve-valve motor,
+where the uncovering of the ports is absolutely positive. The cars
+equipped with these valves were a success in long-distance auto races.
+Claims made for this type of valve mechanism include the possibility of
+a higher number of revolutions and consequently greater engine power.
+With the spring-controlled, single-cam operated valve a point is reached
+where the spring is not capable of returning the valve to its seat
+before the cam has again begun its opening movement. It is possible to
+extend the limits considerably by using a light valve on a strong
+spring, but the valve still remains a limiting factor in the speed of
+the motor.
+
+[Illustration: Fig. 111.--Timing Diagram Showing Peculiar Valve Timing
+of Gnome "Monosoupape" Rotary Motor.]
+
+A part sectional view through a cylinder of an engine designed by G.
+Michaux is shown at Fig. 112, A. There are two valves per cylinder,
+inclined at about ten degrees from the vertical. The valve-stems are of
+large diameter, as owing to positive control, there is no necessity of
+lightening this part in an unusual degree. A single overhead cam-shaft
+has eight pairs of cams, which are shown in detail at B. For each valve
+there is a three-armed rocker, one arm of which is connected to the stem
+of the valve and the two others are in contact respectively with the
+opening and closing cams. The connection to the end of the valve-stem is
+made by a short connecting link, which is screwed on to the end of the
+valve-stem and locked in position. This allows some adjustment to be
+made between the valves and the actuating rocker. It will be evident
+that one cam and one rocker arm produce the opening of the valve and
+that the corresponding rocker arm and cam result in the closing of the
+valve. If the opening cam has the usual convex profile, the closing cam
+has a correspondingly concave profile. It will be noticed that a light
+valve-spring is shown in drawing. This is provided to give a final
+seating to its valve after it has been closed by the cam. This is not
+absolutely necessary, as an engine has been run successfully without
+these springs. The whole mechanism is contained within an overhead
+aluminum cover.
+
+[Illustration: Fig. 112.--Two Methods of Operating Valves by Positive
+Cam Mechanism Which Closes as Well as Opens Them.]
+
+The positive-valve system used on the De Lage motor is shown at D. In
+this the valves are actuated as shown in sectional views D and E. The
+valve system is unique in that four valves are provided per cylinder,
+two for exhaust and two for intake. The valves are mounted side by side,
+as shown at E, so the double actuator member may be operated by a single
+set of cams. The valve-operating member consists of a yoke having guide
+bars at the top and bottom. The actuating cam works inside of this yoke.
+The usual form of cam acts on the lower portion of the yoke to open the
+valve, while the concave cam acts on the upper part to close the valves.
+In this design provision is made for expansion of the valve-stems due to
+heat, and these are not positively connected to the actuating member. As
+shown at E, the valves are held against the seat by short coil springs
+at the upper end of the stem. These are very stiff and are only intended
+to provide for expansion. A slight space is left between the top of the
+valve-stem and the portion of the operating member that bears against
+them when the regular profile cam exerts its pressure on the bottom of
+the valve-operating mechanism. Another novelty in this motor design is
+that the cam-shafts and the valve-operating members are carried in
+casing attached above the motor by housing supports in the form of small
+steel pillars. The overhead cam-shafts are operated by means of bevel
+gearing.
+
+
+FOUR VALVES PER CYLINDER
+
+[Illustration: Fig. 113.--Diagram Comparing Two Large Valves and Four
+Small Ones of Practically the Same Area. Note How Easily Small Valves
+are Installed to Open Directly Into the Cylinder.]
+
+Mention has been previously made of the sixteen-valve four-cylinder
+Duesenberg motor and its great power output for the piston displacement.
+This is made possible by the superior volumetric efficiency of a motor
+provided with four valves in each cylinder instead of but two. This
+principle was thoroughly tried out in racing automobile motors, and is
+especially valuable in permitting of greater speed and power output from
+simple four- and six-cylinder engines. On eight- and twelve-cylinder
+types, it is doubtful if the resulting complication due to using a very
+large number of valves would be worth while. When extremely large valves
+are used, as shown in diagram at Fig. 113, it is difficult to have them
+open directly into the cylinder, and pockets are sometimes necessary. A
+large valve would weigh more than two smaller valves having an area
+slightly larger in the aggregate; it would require a stiffer valve
+spring on account of its greater weight. A certain amount of metal in
+the valve-head is necessary to prevent warping; therefore, the inertia
+forces will be greater in the large valve than in the two smaller
+valves. As a greater port area is obtained by the use of two valves,
+the gases will be drawn into the cylinder or expelled faster than with a
+lesser area. Even if the areas are practically the same as in the
+diagram at Fig. 113, the smaller valves may have a greater lift without
+imposing greater stresses on the valve-operating mechanism and quicker
+gas intake and exhaust obtained. The smaller valves are not affected by
+heat as much as larger ones are. The quicker gas movements made
+possible, as well as reduction of inertia forces, permits of higher
+rotative speed, and, consequently, greater power output for a given
+piston displacement. The drawings at Fig. 114 show a sixteen-valve motor
+of the four-cylinder type that has been designed for automobile racing
+purposes, and it is apparent that very slight modifications would make
+it suitable for aviation purposes. Part of the efficiency is due to the
+reduction of bearing friction by the use of ball bearings, but the
+multiple-valve feature is primarily responsible for the excellent
+performance.
+
+[Illustration: Fig. 114.--Sectional Views of Sixteen-Valve Four-Cylinder
+Automobile Racing Engine That May Have Possibilities for Aviation
+Service.]
+
+[Illustration: Fig. 115.--Front View of Curtiss OX-3 Aviation Motor,
+Showing Unconventional Valve Action by Concentric Push Rod and Pull
+Tube.]
+
+
+
+
+CHAPTER IX
+
+ Constructional Details of Pistons--Aluminum Cylinders and
+ Pistons--Piston Ring Construction--Leak Proof Piston Rings--
+ Keeping Oil Out of Combustion Chamber--Connecting Rod Forms--
+ Connecting Rods for Vee Engines--Cam-Shaft and Crank-Shaft
+ Designs--Ball Bearing Crank-Shafts--Engine Base Construction.
+
+
+CONSTRUCTIONAL DETAILS OF PISTONS
+
+The piston is one of the most important parts of the gasoline motor
+inasmuch as it is the reciprocating member that receives the impact of
+the explosion and which transforms the power obtained by the combustion
+of gas to mechanical motion by means of the connecting rod to which it
+is attached. The piston is one of the simplest elements of the motor,
+and it is one component which does not vary much in form in different
+types of motors. The piston is a cylindrical member provided with a
+series of grooves in which packing rings are placed on the outside and
+two bosses which serve to hold the wrist pin in its interior. It is
+usually made of cast iron or aluminum, though in some motors where
+extreme lightness is desired, such as those used for aeronautic work, it
+may be made of steel. The use of the more resisting material enables the
+engineer to use lighter sections where it is important that the weight
+of this member be kept as low as possible consistent with strength.
+
+[Illustration: Fig. 116.--Forms of Pistons Commonly Employed in Gasoline
+Engines. A--Dome Head Piston and Three Packing Rings. B--Flat Top Form
+Almost Universally Used. C--Concave Piston Utilized in Knight Motors and
+Some Having Overhead Valves. D--Two-Cycle Engine Member with Deflector
+Plate Cast Integrally. E--Differential of Two-Diameter Piston Used in
+Some Engines Operating on Two-Cycle Principle.]
+
+A number of piston types are shown at Fig. 116. That at A has a round
+top and is provided with four split packing rings and two oil grooves. A
+piston of this type is generally employed in motors where the combustion
+chamber is large and where it is desired to obtain a higher degree of
+compression than would be possible with a flat top piston. This
+construction is also stronger because of the arched piston top. The most
+common form of piston is that shown at B, and it differs from that
+previously described only in that it has a flat top. The piston outlined
+in section at C is a type used on some of the sleeve-valve motors of the
+Knight pattern, and has a concave head instead of the convex form shown
+at A. The design shown at D in side and plan views is the conventional
+form employed in two-cycle engines. The deflector plate on the top of
+the cylinder is cast integral and is utilized to prevent the incoming
+fresh gases from flowing directly over the piston top and out of the
+exhaust port, which is usually opposite the inlet opening. On these
+types of two-cycle engines where a two-diameter cylinder is employed,
+the piston shown at E is used. This is known as a "differential
+piston," and has an enlarged portion at its lower end which fits the
+pumping cylinder. The usual form of deflector plate is provided at the
+top of the piston and one may consider it as two pistons in one.
+
+[Illustration: Fig. 117.--Typical Methods of Piston Pin Retention
+Generally Used in Engines of American Design. A--Single Set Screw and
+Lock Nut. B--Set Screw and Check Nut Fitting Groove in Wrist Pin. C,
+D--Two Locking Screws Passing Into Interior of Hollow Wrist Pin.
+E--Split Ring Holds Pin in Place. F--Use of Taper Expanding Plugs
+Outlined. G--Spring Pressed Plunger Type. H--Piston Pin Pinned to
+Connecting Rod. I--Wrist Pin Clamped in Connecting Rod Small End by
+Bolt.]
+
+[Illustration: Fig. 118.--Typical Piston and Connecting Rod Assembly.]
+
+[Illustration: Fig. 119.--Parts of Sturtevant Aviation Engine.
+A--Cylinder Head Showing Valves. B--Connecting Rod. C--Piston and
+Rings.]
+
+One of the important conditions in piston design is the method of
+securing the wrist pin which is used to connect the piston to the upper
+end of the connecting rod. Various methods have been devised to keep the
+pin in place, the most common of these being shown at Fig. 117. The
+wrist pin should be retained by some positive means which is not liable
+to become loose under the vibratory stresses which obtain at this point.
+If the wrist pin was free to move it would work out of the bosses
+enough so that the end would bear against the cylinder wall. As it is
+usually made of steel, which is a harder material than cast iron used in
+cylinder construction, the rubbing action would tend to cut a groove in
+the cylinder wall which would make for loss of power because it would
+permit escape of gas. The wrist pin member is a simple cylindrical
+element that fits the bosses closely, and it may be either hollow or
+solid stock. A typical piston and connecting rod assembly which shows a
+piston in section also is given at Fig. 118. The piston of the
+Sturtevant aeronautical motor is shown at Fig. 119, the aluminum piston
+of the Thomas airplane motor with piston rings in place is shown at Fig.
+120. A good view of the wrist pin and connecting rod are also given. The
+iron piston of the Gnome "Monosoupape" airplane engine and the
+unconventional connecting rod assembly are clearly depicted at Fig 121.
+
+[Illustration: Fig. 120.--Aluminum Piston and Light But Strong Steel
+Connecting Rod and Wrist Pin of Thomas Aviation Engine.]
+
+The method of retention shown at A is the simplest and consists of a set
+screw having a projecting portion passing into the wrist pin and
+holding it in place. The screw is kept from turning or loosening by
+means of a check nut. The method outlined at B is similar to that shown
+at A, except that the wrist pin is solid and the point of the set screw
+engages an annular groove turned in the pin for its reception. A very
+positive method is shown at C. Here the retention screws pass into the
+wrist pin and are then locked by a piece of steel wire which passes
+through suitable holes in the ends. The method outlined at D is
+sometimes employed, and it varies from that shown at C only in that the
+locking wire, which is made of spring steel, is passed through the heads
+of the locking screws. Some designers machine a large groove around the
+piston at such a point that when the wrist pin is put in place a large
+packing ring may be sprung in the groove and utilized to hold the wrist
+pin in place.
+
+[Illustration: Fig. 121.--Cast Iron Piston of "Monosoupape" Gnome Engine
+Installed On One of the Short Connecting Rods.]
+
+The system shown at F is not so widely used as the simpler methods,
+because it is more costly and does not offer any greater security when
+the parts are new than the simple lock shown at A. In this a hollow
+wrist pin is used, having a tapered thread cut at each end. The wrist
+pin is slotted at three or four points, for a distance equal to the
+length of the boss, and when taper expansion plugs are screwed in place
+the ends of the wrist pin are expanded against the bosses. This method
+has the advantage of providing a certain degree of adjustment if the
+wrist pin should loosen up after it has been in use for some time. The
+taper plugs would be screwed in deeper and the ends of the wrist pin
+expanded proportionately to take up the loss motion. The method shown at
+G is an ingenious one. One of the piston bosses is provided with a
+projection which is drilled out to receive a plunger. The wrist pin is
+provided with a hole of sufficient size to receive the plunger, which is
+kept in place by means of a spring in back of it. This makes a very
+positive lock and one that can be easily loosened when it is desired to
+remove the wrist pin. To unlock, a piece of fine rod is thrust into the
+hole at the bottom of the boss which pushes the plunger back against the
+spring until the wrist pin can be pushed out of the piston.
+
+Some engineers think it advisable to oscillate the wrist pin in the
+piston bosses, instead of in the connecting rod small end. It is argued
+that this construction gives more bearing surface at the wrist pin and
+also provides for more strength because of the longer bosses that can be
+used. When this system is followed the piston pin is held in place by
+locking it to the connecting rod by some means. At H the simplest method
+is outlined. This consisted of driving a taper pin through both rod and
+wrist pin and then preventing it from backing out by putting a split
+cotter through the small end of the tapered locking pin. Another method,
+which is depicted at I, consists of clamping the wrist pin by means of a
+suitable bolt which brings the slit connecting rod end together as
+shown.
+
+
+ALUMINUM FOR CYLINDERS AND PISTONS
+
+Aluminum pistons outlined at Fig. 122, have replaced cast iron members
+in many airplane engines, as these weigh about one-third as much as the
+cast iron forms of the same size, while the reduction in the inertia
+forces has made it possible to increase the engine speed without
+correspondingly stressing the connecting rods, crank-shaft and engine
+bearings.
+
+[Illustration: Fig. 122.--Types of Aluminum Pistons Used In Aviation
+Engines.]
+
+Aluminum has not only been used for pistons, but a number of motors will
+be built for the coming season that will use aluminum cylinder block
+castings as well. Of course, the aluminum alloy is too soft to be used
+as a bearing for the piston, and it will not withstand the hammering
+action of the valve. This makes the use of cast iron or steel imperative
+in all motors. When used in connection with an aluminum cylinder block
+the cast iron pieces are placed in the mould so that they act as
+cylinder liners and valve seats, and the molten metal is poured around
+them when the cylinder is cast. It is said that this construction
+results in an intimate bond between the cast iron and the surrounding
+aluminum metal. Steel liners may also be pressed into the aluminum
+cylinders after these are bored out to receive them. Aluminum has for a
+number of years been used in many motor car parts. Alloys have been
+developed that have greater strength than cast iron and that are not so
+brittle. Its use for manifolds and engine crank and gear cases has been
+general for a number of years.
+
+At first thought it would seem as though aluminum would be entirely
+unsuited for use in those portions of internal combustion engines
+exposed to the heat of the explosion, on account of the low melting
+point of that metal and its disadvantageous quality of suddenly
+"wilting" when a critical point in the temperature is reached. Those who
+hesitated to use aluminum on account of this defect lost sight of the
+great heat conductivity of that metal, which is considerably more than
+that of cast iron. It was found in early experiments with aluminum
+pistons that this quality of quick radiation meant that aluminum pistons
+remained considerably cooler than cast iron ones in service, which was
+attested to by the reduced formation of carbon deposit thereon. The use
+of aluminum makes possible a marked reduction in power plant weight. A
+small four-cylinder engine which was not particularly heavy even with
+cast iron cylinders was found to weigh 100 pounds less when the cylinder
+block, pistons, and upper half of the crank-case had been made of
+aluminum instead of cast iron. Aluminum motors are no longer an
+experiment, as a considerable number of these have been in use on cars
+during the past year without the owners of the cars being apprised of
+the fact. Absolutely no complaint was made in any case of the aluminum
+motor and it was demonstrated, in addition to the saving in weight, that
+the motors cost no more to assemble and cooled much more efficiently
+than the cast iron form. One of the drawbacks to the use of aluminum is
+its growing scarcity, which results in making it a "near precious"
+metal.
+
+
+PISTON RING CONSTRUCTION
+
+As all pistons must be free to move up and down in the cylinder with
+minimum friction, they must be less in diameter than the bore of the
+cylinder. The amount of freedom or clearance provided varies with the
+construction of the engine and the material the piston is made of, as
+well as its size, but it is usual to provide from .005 to .010 of an
+inch to compensate for the expansion of the piston due to heat and also
+to leave sufficient clearance for the introduction of lubricant between
+the working surfaces. Obviously, if the piston were not provided with
+packing rings, this amount of clearance would enable a portion of the
+gases evolved when the charge is exploded to escape by it into the
+engine crank-case. The packing members or piston rings, as they are
+called, are split rings of cast iron, which are sprung into suitable
+grooves machined on the exterior of the piston, three or four of these
+being the usual number supplied. These have sufficient elasticity so
+that they bear tightly against the cylinder wall and thus make a
+gas-tight joint. Owing to the limited amount of surface in contact with
+the cylinder wall and the elasticity of the split rings the amount of
+friction resulting from the contact of properly fitted rings and the
+cylinder is not of enough moment to cause any damage and the piston is
+free to slide up and down in the cylinder bore.
+
+[Illustration: Fig. 123.--Types of Piston Rings and Ring Joints.
+A--Concentric Ring. B--Eccentrically Machined Form. C--Lap Joint Ring.
+D--Butt Joint, Seldom Used. E--Diagonal Cut Member, a Popular Form.]
+
+These rings are made in two forms, as outlined at Fig. 123. The design
+shown at A is termed a "concentric ring," because the inner circle is
+concentric with the outer one and the ring is of uniform thickness at
+all points. The ring shown at B is called an "eccentric ring," and it is
+thicker at one part than at others. It has theoretical advantages in
+that it will make a tighter joint than the other form, as it is claimed
+its expansion due to heat is more uniform. The piston rings must be
+split in order that they may be sprung in place in the grooves, and also
+to insure that they will have sufficient elasticity to take the form of
+the cylinder at the different points in their travel. If the cylinder
+bore varies by small amounts the rings will spring out at the points
+where the bore is larger than standard, and spring in at those portions
+where it is smaller than standard.
+
+It is important that the joint should be as nearly gas-tight as
+possible, because if it were not a portion of the gases would escape
+through the slots in the piston rings. The joint shown at C is termed a
+"lap joint," because the ends of the ring are cut in such a manner that
+they overlap. This is the approved joint. The butt joint shown at D is
+seldom used and is a very poor form, the only advantage being its
+cheapness. The diagonal cut shown at E is a compromise between the very
+good form shown at C and the poor joint depicted at D. It is also widely
+used, though most constructors prefer the lap joint, because it does not
+permit the leakage of gas as much as the other two types.
+
+There seems to be some difference of opinion relative to the best piston
+ring type--some favoring the eccentric pattern, others the concentric
+form. The concentric ring has advantages from the lubricating engineer's
+point of view; as stated by the Platt & Washburn Company in their
+text-book on engine lubrication, the smaller clearance behind the ring
+possible with the ring of uniform section is advantageous.
+
+Fig. 124, A, shows a concentric piston ring in its groove. Since the
+ring itself is concentric with the groove, very small clearance between
+the back of the ring and the bottom of its groove may be allowed. Small
+clearance leaves less space for the accumulation of oil and carbon
+deposits. The gasket effect of this ring is uniform throughout the
+entire length of its edges, which is its marked advantage over the
+eccentric ring. This type of piston ring rarely burns fast in its
+groove. There are a large number of different concentric rings
+manufactured of different designs and of different efficiency.
+
+[Illustration: Fig. 124.--Diagrams Showing Advantages of Concentric
+Piston Rings.]
+
+Figs. 124, B and 124, C show eccentric rings assembled in the ring
+groove. It will be noted that there is a large space between the thin
+ends of this ring and the bottom of the groove. This empty space fills
+up with oil which in the case of the upper ring frequently is
+carbonized, restricting the action of the ring and nullifying its
+usefulness. The edges of the thin ends are not sufficiently wide to
+prevent rapid escape of gases past them. In a practical way this leakage
+means loss of compression and noticeable drop in power. When new and
+properly fitted, very little difference can be noted between the
+tightness of eccentric and concentric rings. Nevertheless, after several
+months' use, a more rapid leakage will always occur past the eccentric
+than past the concentric. If continuous trouble with the carbonization
+of cylinders, smoking and sooting of spark-plugs is experienced, it is
+a sure indication that mechanical defects exist in the engine, assuming
+of course, that a suitable oil has been used. Such trouble can be
+greatly lessened, if not entirely eliminated, by the application of
+concentric rings (lap joint), of any good make, properly fitted into the
+grooves of the piston. Too much emphasis cannot be put upon this point.
+If the oil used in the engine is of the correct viscosity, and serious
+carbon deposit, smoking, etc., still result, the only certain remedy
+then is to have the cylinders rebored and fitted with properly designed,
+oversized pistons and piston rings.
+
+
+LEAK-PROOF PISTON RINGS
+
+In order to reduce the compression loss and leakage of gas by the
+ordinary simple form of diagonal or lap joint one-piece piston ring a
+number of compound rings have been devised and are offered by their
+makers to use in making replacements. The leading forms are shown at
+Fig. 125. That shown at A is known as the "Statite" and consists of
+three rings, one carried inside while the other two are carried on the
+outside. The ring shown at B is a double ring and is known as the
+McCadden. This is composed of two thin concentric lap joint rings so
+disposed relative to each other that the opening in the inner ring comes
+opposite to the opening in the outer ring.
+
+The form shown at C is known as the "Leektite," and is a single ring
+provided with a peculiar form of lap and dove tail joint. The ring shown
+at D is known as the "Dunham" and is of the double concentric type being
+composed of two rings with lap joints which are welded together at a
+point opposite the joint so that there is no passage by which the gas
+can escape. The Burd high compression ring is shown at E. The joints of
+these rings are sealed by means of an H-shaped coupler of bronze which
+closes the opening. The ring ends are made with tongues which interlock
+with the coupling. The ring shown at F is called the "Evertite" and is
+a three-piece ring composed of three members as shown in the sectional
+view below the ring. The main part or inner ring has a circumferential
+channel in which the two outer rings lock, the resulting cross-section
+being rectangular just the same as that of a regular pattern ring. All
+three rings are diagonally split and the joints are spaced equally and
+the distances maintained by small pins. This results in each joint being
+sealed by the solid portion of the other rings.
+
+[Illustration: Fig. 125.--Leak-Proof and Other Compound Piston Rings.]
+
+The use of a number of light steel rings instead of one wide ring in the
+groove is found on a number of automobile power plants, but as far as
+known, this construction is not used in airplane power plants. It is
+contended that where a number of light rings is employed a more flexible
+packing means is obtained and the possibility of leakage is reduced.
+Rings of this design are made of square section steel wire and are given
+a spring temper. Owing to the limited width the diagonal cut joint is
+generally employed instead of the lap joint which is so popular on wider
+rings.
+
+
+KEEPING OIL OUT OF COMBUSTION CHAMBERS
+
+An examination of the engine design that is economical in oil
+consumption discloses the use of tight piston rings, large centrifugal
+rings on the crank-shaft where it passes through the case, ample cooling
+fins in the pistons, vents between the crank-case chamber and the valve
+enclosures, etc. Briefly put, cooling of the oil in this engine has been
+properly cared for and leakage reduced to a minimum. To be specific
+regarding details of design: Oil surplus can be kept out of the
+explosion chambers by leaving the lower edge of the piston skirt sharp
+and by the use of a shallow groove (C), Fig. 126, just below the lower
+piston ring. Small holes are bored through the piston walls at the base
+of this groove and communicate with the crank-case. The similarity of
+the sharp edges of piston skirt (D) and piston ring to a carpenter's
+plane bit, makes their operation plain.
+
+[Illustration: Fig. 126.--Sectional View of Engine Showing Means of
+Preventing Oil Leakage By Piston Rings.]
+
+The cooling of oil in the sump (A) can be accomplished most effectively
+by radiating fins on its outer surface. The lower crank-case should be
+fully exposed to the outer air. A settling basin for sediment (B) should
+be provided having a cubic content not less than one-tenth of the total
+oil capacity as outlined at Fig. 126. The depth of this basin should be
+at least 2-1/2 inches, and its walls vertical, as shown, to reduce the
+mixing of sediment with the oil in circulation. The inlet opening to the
+oil pump should be near the top of the sediment basin in order to
+prevent the entrance into the pump with the oil of any solid matter or
+water condensed from the products of combustion. This sediment basin
+should be drained after every five to seven hours air service of an
+airplane engine. Concerning filtering screens there is little to be
+said, save that their areas should be ample and the mesh coarse enough
+(one-sixteenth of an inch) to offer no serious resistance to the free
+flow of cold or heavy oil through them; otherwise the oil in the
+crank-case may build up above them to an undesirable level. The
+necessary frequency of draining and flushing out the oil sump differs
+greatly with the age (condition) of the engine and the suitability of
+the oil used. In broad terms, the oil sump of a new engine should be
+thoroughly drained and flushed with kerosene at the end of the first
+200 miles, next at the end of 500 miles and thereafter every 1,000
+miles. While these instructions apply specifically to automobile motors,
+it is very good practice to change the oil in airplane engines
+frequently. In many cases, the best results have been secured when the
+oil supply is completely replenished every five hours that the engine is
+in operation.
+
+
+CONNECTING ROD FORMS
+
+The connecting rod is the simple member that joins the piston to the
+crank-shaft and which transmits the power imparted to the piston by the
+explosion so that it may be usefully applied. It transforms the
+reciprocating movement of the piston to a rotary motion at the
+crank-shaft. A typical connecting rod and its wrist pin are shown at
+Fig. 120. It will be seen that it has two bearings, one at either end.
+The small end is bored out to receive the wrist pin which joins it to
+the piston, while the large end has a hole of sufficient size to go on
+the crank-pin. The airplane and automobile engine connecting rod is
+invariably a steel forging, though in marine engines it is sometimes
+made a steel or high tensile strength bronze casting. In all cases it is
+desirable to have softer metals than the crank-shaft and wrist pin at
+the bearing point, and for this reason the connecting rod is usually
+provided with bushings of anti-friction or white metal at the lower end,
+and bronze at the upper. The upper end of the connecting rod may be one
+piece, because the wrist pin can be introduced after it is in place
+between the bosses of the piston. The lower bearing must be made in two
+parts in most cases, because the crank-shaft cannot be passed through
+the bearing owing to its irregular form. The rods of the Gnome engine
+are all one piece types, as shown at Fig. 127, owing to the construction
+of the "mother" rod which receives the crank-pins. The complete
+connecting rod assembly is shown in Fig. 121, also at A, Fig. 127. The
+"mother" rod, with one of the other rods in place and one about to be
+inserted, is shown at Fig. 127, B. The built-up crank-shaft which makes
+this construction feasible is shown at Fig. 127, C.
+
+[Illustration: Fig. 127.--Connecting Rod and Crank-Shaft Construction of
+Gnome "Monosoupape" Engine.]
+
+Some of the various designs of connecting rods that have been used are
+shown at Fig. 128. That at A is a simple form often employed in
+single-cylinder motors, having built-up crank-shafts. Both ends of the
+connecting rod are bushed with a one-piece bearing, as it can be
+assembled in place before the crank-shaft assembly is built up. A
+built-up crank-shaft such as this type of connecting rod would be used
+with is shown at Fig. 106. The pattern shown at B is one that has been
+used to some extent on heavy work, and is known as the "marine type." It
+is made in three pieces, the main portion being a steel forging having a
+flanged lower end to which the bronze boxes are secured by bolts. The
+modified marine type depicted at C is the form that has received the
+widest application in automobile and aviation engine construction. It
+consists of two pieces, the main member being a steel drop forging
+having the wrist-pin bearing and the upper crank-pin bearing formed
+integral, while the lower crank-pin bearing member is a separate forging
+secured to the connecting rod by bolts. In this construction bushings of
+anti-friction metal are used at the lower end, and a bronze bushing is
+forced into the upper- or wrist-pin end. The rod shown at D has also
+been widely used. It is similar in construction to the form shown at C,
+except that the upper end is split in order to permit of a degree of
+adjustment of the wrist-pin bushing, and the lower bearing cap is a
+hinged member which is retained by one bolt instead of two. When it is
+desired to assemble it on the crank-shaft the lower cap is swung to one
+side and brought back into place when the connecting rod has been
+properly located. Sometimes the lower bearing member is split diagonally
+instead of horizontally, such a construction being outlined at E.
+
+[Illustration: Fig. 128.--Connecting Rod Types Summarized.
+A--Single Connecting Rod Made in One Piece, Usually Fitted in Small
+Single-Cylinder Engines Having Built-Up Crank-Shafts. B--Marine Type, a
+Popular Form on Heavy Engines. C--Conventional Automobile Type, a
+Modified Marine Form. D--Type Having Hinged Lower Cap and Split Wrist
+Pin Bushing. E--Connecting Rod Having Diagonally Divided Big End.
+F--Ball-Bearing Rod. G--Sections Showing Structural Shapes Commonly
+Employed in Connecting Rod Construction.]
+
+In a number of instances, instead of plain bushed bearings anti-friction
+forms using ball or rollers have been used at the lower end. A
+ball-bearing connecting rod is shown at F. The big end may be made in
+one piece, because if it is possible to get the ball bearing on the
+crank-pins it will be easy to put the connecting rod in place. Ball
+bearings are not used very often on connecting rod big ends because of
+difficulty of installation, though when applied properly they give
+satisfactory service and reduce friction to a minimum. One of the
+advantages of the ball bearing is that it requires no adjustment,
+whereas the plain bushings depicted in the other connecting rods must be
+taken up from time to time to compensate for wear.
+
+This can be done in forms shown at B, C, D, and E by bringing the lower
+bearing caps closer to the upper one and scraping out the brasses to fit
+the shaft. A number of liners or shims of thin brass or copper stock,
+varying from .002 inch to .005 inch, are sometimes interposed between
+the halves of the bearings when it is first fitted to the crank-pin. As
+the brasses wear the shims may be removed and the portions of the
+bearings brought close enough together to take up any lost motion that
+may exist, though in some motors no shims are provided and depreciation
+can be remedied only by installing new brasses and scraping to fit.
+
+[Illustration: Fig. 129.--Double Connecting Rod Assembly For Use On
+Single Crank-Pin of Vee Engine.]
+
+The various structural shapes in which connecting rods are formed are
+shown in section at G. Of these the I section is most widely used in
+airplane engines, because it is strong and a very easy shape to form by
+the drop-forging process or to machine out of the solid bar when extra
+good steel is used. Where extreme lightness is desired, as in small
+high-speed motors used for cycle propulsion, the section shown at the
+extreme left is often used. If the rod is a cast member as in some
+marine engines, the cross, hollow cylinder, or U sections are sometimes
+used. If the sections shown at the right are employed, advantage is
+often taken of the opportunity for passing lubricant through the center
+of the hollow round section on vertical motors or at the bottom of the U
+section, which would be used on a horizontal cylinder power plant.
+
+[Illustration: Fig. 130.--Another Type of Double Connecting Rod for Vee
+Engines.]
+
+Connecting rods of Vee engines are made in two distinct styles. The
+forked or "scissors" joint rod assembly is employed when the cylinders
+are placed directly opposite each other. The "blade" rod, as shown at
+Fig. 129, fits between the lower ends of the forked rod, which oscillate
+on the bearing which encircles the crank-pin. The lower end of the
+"blade" rod is usually attached to the bearing brasses, the ends of the
+"forked" rod move on the outer surfaces of the brasses. Another form of
+rod devised for use under these conditions is shown at Fig. 130 and
+installed in an aviation engine at Fig. 132. In this construction the
+shorter rod is attached to a boss on the master rod by a short pin to
+form a hinge and to permit the short rod to oscillate as the conditions
+dictate. This form of rod can be easily adjusted when the bearing
+depreciates, a procedure that is difficult with the forked type rod. The
+best practice, in the writer's opinion, is to stagger the cylinders and
+use side-by-side rods as is done in the Curtiss engine. Each rod may be
+fitted independently of the other and perfect compensation for wear of
+the big ends is possible.
+
+[Illustration: Fig. 131.--Part Sectional View of Wisconsin Aviation
+Engine, Showing Four-Bearing Crank-Shaft, Overhead Cam-Shaft, and Method
+of Combining Cylinders in Pairs.]
+
+[Illustration: Fig. 132.--Part Sectional View of Renault Twelve-Cylinder
+Water-Cooled Engine, Showing Connecting Rod Construction and Other
+Important Internal Parts.]
+
+
+CAM-SHAFT AND CRANK-SHAFT DESIGN
+
+Before going extensively into the subject of crank-shaft construction it
+will be well to consider cam-shaft design, which is properly a part of
+the valve system and which has been considered in connection with the
+other elements which have to do directly with cylinder construction to
+some extent. Cam-shafts are usually simple members carried at the base
+of the cylinder in the engine case of Vee type motors by suitable
+bearings and having the cams employed to lift the valves attached at
+intervals. A typical cam-shaft design is shown at Fig. 133. Two main
+methods of cam-shaft construction are followed--that in which the cams
+are separate members, keyed and pinned to the shaft, and the other where
+the cams are formed integral, the latter being the most suitable for
+airplane engine requirements.
+
+[Illustration: Fig. 133.--Typical Cam-Shaft, with Valve Lifting Cams and
+Gears to Operate Auxiliary Devices Forged Integrally.]
+
+The cam-shafts shown at Figs. 133 and 134, B, are of the latter type, as
+the cams are machined integrally. In this case not only the cams but
+also the gears used in driving the auxiliary shafts are forged integral.
+This is a more expensive construction, because of the high initial cost
+of forging dies as well as the greater expense of machining. It has the
+advantage over the other form in which the cams are keyed in place in
+that it is stronger, and as the cams are a part of the shaft they can
+never become loose, as might be possible where they are separately
+formed and assembled on a simple shaft.
+
+[Illustration: Fig. 134.--Important Parts of Duesenberg Aviation Engine.
+A--Three Main Bearing Crank-Shaft. B--Cam-Shaft with Integral Cams.
+C--Piston and Connecting Rod Assembly. D--Valve Rocker Group. E--Piston.
+F--Main Bearing Brasses.]
+
+The importance of the crank-shaft has been previously considered, and
+some of its forms have been shown in views of the motors presented in
+earlier portions of this work. The crank-shaft is one of the parts
+subjected to the greatest strain and extreme care is needed in its
+construction and design, because practically the entire duty of
+transmitting the power generated by the motor to the gearset devolves
+upon it. Crank-shafts are usually made of high tensile strength steel of
+special composition. They may be made in four ways, the most common
+being from a drop or machine forging which is formed approximately to
+the shape of the finished shaft and in rare instances (experimental
+motors only) they may be steel castings. Sometimes they are made from
+machine forgings, where considerably more machine work is necessary than
+would be the case where the shaft is formed between dies. Some engineers
+favor blocking the shaft out of a solid slab of metal and then machining
+this rough blank to form. In some radial-cylinder motors of the Gnome
+and Le Rhone type the crank-shafts are built up of two pieces, held
+together by taper fastenings or bolts.
+
+[Illustration: Fig. 135.--Showing Method of Making Crank-Shaft. A--The
+Rough Steel Forging Before Machining. B--The Finished Six-Throw,
+Seven-Bearing Crank-Shaft.]
+
+The form of the shaft depends on the number of cylinders and the form
+has material influence on the method of construction. For instance, a
+four-cylinder crank-shaft could be made by either of the methods
+outlined. On the other hand, a three- or six-cylinder shaft is best made
+by the machine forging process, because if drop forged or cut from the
+blank it will have to be heated and the crank throws bent around so that
+the pins will lie in three planes one hundred and twenty degrees apart,
+while the other types described need no further attention, as the
+crank-pins lie in planes one hundred and eighty degrees apart. This can
+be better understood by referring to Fig. 135, which shows a
+six-cylinder shaft in the rough and finished stages. At A the
+appearance of the machine forging before any of the material is removed
+is shown, while at B the appearance of the finished crank-shaft is
+clearly depicted. The built-up crank-shaft is seldom used on
+multiple-cylinder motors, except in some cases where the crank-shafts
+revolve on ball bearings as in some automobile racing engines.
+
+[Illustration: Fig. 136.--Showing Form of Crank-Shaft for Twin-Cylinder
+Opposed Power Plant.]
+
+[Illustration: Fig. 137.--Crank-Shaft of Thomas-Morse Eight-Cylinder Vee
+Engine.]
+
+Crank-shaft form will vary with a number of cylinders and it is possible
+to use a number of different arrangements of crank-pins and bearings for
+the same number of cylinders. The simplest form of crank-shaft is that
+used on simple radial cylinder motors as it would consist of but one
+crank-pin, two webs, and the crank-shaft. As the number of cylinders
+increase in Vee motors as a general rule more crank-pins are used. The
+crank-shaft that would be used on a two-cylinder opposed motor is shown
+at Fig. 136. This has two throws and the crank-pins are spaced 180
+degrees apart. The bearings are exceptionally long. Four-cylinder
+crank-shafts may have two, three or five main bearings and three or four
+crank-pins. In some forms of two-bearing crank-shafts, such as used when
+four-cylinders are cast in a block, or unit casting, two of the pistons
+are attached to one common crank-pin, so that in reality the crank-shaft
+has but three crank-pins. A typical three bearing, four-cylinder
+crank-shaft is shown at Fig. 134, A. The same type can be used for an
+eight-cylinder Vee engine, except for the greater length of crank-pins
+to permit of side by side rods as shown at Fig. 137. Six cylinder
+vertical tandem and twelve-cylinder Vee engine crank-shafts usually have
+four or seven main bearings depending upon the disposition of the
+crank-pins and arrangement of cylinders. At Fig. 138, A, the bottom
+view of a twelve-cylinder engine with bottom half of crank case removed
+is given. This illustrates clearly the arrangement of main bearings when
+the crank-shaft is supported on four journals. The crank-shaft shown at
+Fig. 138, B, is a twelve-cylinder seven-bearing type.
+
+[Illustration: Fig. 138.--Crank-Case and Crank-Shaft Construction for
+Twelve-Cylinder Motors. A--Duesenberg. B--Curtiss.]
+
+[Illustration: Fig. 139.--Counterbalanced Crank-Shafts Reduce Engine
+Vibration and Permit of Higher Rotative Speeds.]
+
+In some automobile engines, extremely good results have been secured in
+obtaining steady running with minimum vibration by counterbalancing the
+crank-shafts as outlined at Fig. 139. The shaft at A is a type suitable
+for a high speed four-cylinder vertical or an eight-cylinder Vee type.
+That at B is for a six-cylinder vertical or a twelve-cylinder V with
+scissors joint rods. If counterbalancing crank-shafts helps in an
+automobile engine, it should have advantages of some moment in airplane
+engines, even though the crank-shaft weight is greater.
+
+
+BALL-BEARING CRANK-SHAFTS
+
+While crank-shafts are usually supported in plain journals there seems
+to be a growing tendency of late to use anti-friction bearings of the
+ball type for their support. This is especially noticeable on block
+motors where but two main bearings are utilized. When ball bearings are
+selected with proper relation to the load which obtains they will give
+very satisfactory service. They permit the crank-shaft to turn with
+minimum friction, and if properly selected will never need adjustment.
+The front end is supported by a bearing which is clamped in such a
+manner that it will take a certain amount of load in a direction
+parallel to the axis of the shaft, while the rear end is so supported
+that the outer race of the bearing has a certain amount of axial freedom
+or "float." The inner race or cone of each bearing is firmly clamped
+against shoulders on the crank-shaft. At the front end of the
+crank-shaft timing gear and a suitable check nut are used, while at the
+back end the bearing is clamped by a threaded retention member between
+the fly-wheel and a shoulder on the crank-shaft. The fly-wheel is held
+in place by a taper and key retention. The ball bearings are carried in
+a light housing of bronze or malleable iron, which in turn are held in
+the crank-case by bolts. The Renault engine uses ball bearings at front
+and rear ends of the crank-shaft, but has plain bearings around
+intermediate crank-shaft journals. The rotary engines of the Gnome, Le
+Rhone and Clerget forms would not be practical if ball bearings were not
+used as the bearing friction and consequent depreciation would be very
+high.
+
+
+ENGINE-BASE CONSTRUCTION
+
+One of the important parts of the power plant is the substantial casing
+or bed member, which is employed to support the cylinders and
+crank-shaft and which is attached directly to the fuselage engine
+supporting members. This will vary widely in form, but as a general
+thing it is an approximately cylindrical member which may be divided
+either vertically or horizontally in two or more parts. Airplane engine
+crank-cases are usually made of aluminum, a material which has about the
+same strength as cast iron, but which only weighs a third as much. In
+rare cases cast iron is employed, but is not favored by most engineers
+because of its brittle nature, great weight and low resistance to
+tensile stresses. Where exceptional strength is needed alloys of bronze
+may be used, and in some cases where engines are produced in large
+quantities a portion of the crank-case may be a sheet steel or aluminum
+stamping.
+
+[Illustration: Fig. 140.--View of Thomas 135 Horse-Power Aeromotor,
+Model 8, Showing Conventional Method of Crank-Case Construction.]
+
+[Illustration: Fig. 141.--Views of Upper Half of Thomas Aeromotor
+Crank-Case.]
+
+Crank-cases are always large enough to permit the crank-shaft and parts
+attached to it to turn inside and obviously its length is determined by
+the number of cylinders and their disposition. The crank-case of the
+radial cylinder or double-opposed cylinder engine would be substantially
+the same in length. That of a four-cylinder will vary in length with
+the method of casting the cylinder. When the four-cylinders are cast in
+one unit and a two-bearing crank-shaft is used, the crank-case is a very
+compact and short member. When a three-bearing crank-shaft is utilized
+and the cylinders are cast in pairs, the engine base is longer than it
+would be to support a block casting, but is shorter than one designed to
+sustain individual cylinder castings and a five-bearing crank-shaft. It
+is now common construction to cast an oil container integral with the
+bottom of the engine base and to draw the lubricating oil from it by
+means of a pump, as shown at Fig. 140. The arms by which the motor is
+supported in the fuselage are substantial-ribbed members cast
+integrally with the upper half.
+
+[Illustration: Fig. 142.--Method of Constructing Eight-Cylinder Vee
+Engine, Possible if Aluminum Cylinder and Crank-Case Castings are Used.]
+
+[Illustration: Fig. 143.--Simple and Compact Crank-Case, Possible When
+Radial Cylinder Engine Design is Followed.]
+
+The approved method of crank-case construction favored by the majority
+of engineers is shown at the top of Fig. 141, bottom side up. The upper
+half not only forms a bed for the cylinder but is used to hold the
+crank-shaft as well. In the illustration, the three-bearing boxes form
+part of the case, while the lower brasses are in the form of separately
+cast caps retained by suitable bolts. In the construction outlined the
+bottom part of the case serves merely as an oil container and a
+protection for the interior mechanism of the motor. The cylinders are
+held down by means of studs screwed into the crank-case top, as shown at
+Fig. 141, lower view. If the aluminum cylinder motor has any future, the
+method of construction outlined at Fig. 142, which has been used in cast
+iron for an automobile motor, might be used for an eight-cylinder Vee
+engine for airplane use. The simplicity of the crank-case needed for a
+revolving cylinder motor and its small weight can be well understood by
+examination of the illustration at Fig. 143, which shows the engine
+crank-case for the nine-cylinder "Monosoupape" Gnome engine. This
+consists of two accurately machined forgings held together by bolts as
+clearly indicated.
+
+
+
+
+CHAPTER X
+
+ Power Plant Installation--Curtiss OX-2 Engine Mounting and
+ Operating Rules--Standard S. A. E. Engine Bed Dimensions--
+ Hall-Scott Engine Installation and Operation--Fuel System Rules
+ --Ignition System--Water System--Preparations to Start Engine--
+ Mounting Radial and Rotary Engines--Practical Hints to Locate
+ Engine Troubles--All Engine Troubles Summarized--Location of
+ Engine Troubles Made Easy.
+
+
+The proper installation of the airplane power plant is more important
+than is generally supposed, as while these engines are usually well
+balanced and run with little vibration, it is necessary that they be
+securely anchored and that various connections to the auxiliary parts be
+carefully made in order to prevent breakage from vibration and that
+attendant risk of motor stoppage while in the air. The type of motor to
+be installed determines the method of installation to be followed. As a
+general rule six-cylinder vertical engine and eight-cylinder Vee type
+are mounted in substantially the same way. The radial, fixed cylinder
+forms and the radial, rotary cylinder Gnome and Le Rhone rotary types
+require an entirely different method of mounting. Some unconventional
+mountings have been devised, notably that shown at Fig. 144, which is a
+six-cylinder German engine that is installed in just the opposite way to
+that commonly followed. The inverted cylinder construction is not
+generally followed because even with pressure feed, dry crank-case type
+lubricating system there is considerable danger of over-lubrication and
+of oil collecting and carbonizing in the combustion chamber and gumming
+up the valve action much quicker than would be the case if the engine
+was operated in the conventional upright position. The reason for
+mounting an engine in this way is to obtain a lower center of gravity
+and also to make for more perfect streamlining of the front end of the
+fuselage in some cases. It is rather doubtful if this slight advantage
+will compensate for the disadvantages introduced by this unusual
+construction. It is not used to any extent now but is presented merely
+to show one of the possible systems of installing an airplane engine.
+
+[Illustration: Fig. 144.--Unconventional Mounting of German Inverted
+Cylinder Motor.]
+
+[Illustration: Fig. 145.--How Curtiss Model OX-2 Motor is Installed in
+Fuselage of Curtiss Tractor Biplane. Note Similarity of Mounting to
+Automobile Power Plant.]
+
+In a number of airplanes of the tractor-biplane type the power plant
+installation is not very much different than that which is found in
+automobile practice. The illustration at Fig. 145 is a very clear
+representation of the method of mounting the Curtiss eight-cylinder 90
+H. P. or model OX-2 engine in the fuselage of the Curtiss JN-4 tractor
+biplane which is so generally used in the United States as a training
+machine. It will be observed that the fuel tank is mounted under a cowl
+directly behind the motor and that it feeds the carburetor by means of
+a flexible fuel pipe. As the tank is mounted higher than the
+carburetor, it will feed that member by gravity. The radiator is mounted
+at the front end of the fuselage and connected to the water piping on
+the motor by the usual rubber hose connections. An oil pan is placed
+under the engine and the top is covered with a hood just as in motor car
+practice. The panels of aluminum are attached to the sides of the
+fuselage and are supplied with doors which open and provide access to
+the carburetor, oil-gauge and other parts of the motor requiring
+inspection. The complete installation with the power plant enclosed is
+given at Fig. 146, and in this it will be observed that the exhaust
+pipes are connected to discharge members that lead the gases above the
+top plane. In the engine shown at Fig. 145 the exhaust flows directly
+into the air at the sides of the machine through short pipes bolted to
+the exhaust gas outlet ports. The installation of the radiator just
+back of the tractor screw insures that adequate cooling will be obtained
+because of the rapid air flow due to the propeller slip stream.
+
+[Illustration: Fig. 146.--Latest Model of Curtiss JN-4 Training Machine,
+Showing Thorough Enclosure of Power Plant and Method of Disposing of the
+Exhaust Gases.]
+
+
+INSTALLATION OF CURTISS OX-2 ENGINE
+
+[Illustration: Fig. 147.--Front View of L. W. F. Tractor Biplane
+Fuselage, Showing Method of Installing Thomas Aeromotor and Method of
+Disposing of Exhaust Gases.]
+
+The following instructions are given in the Curtiss Instruction Book for
+installing the OX-2 engine and preparing it for flights, and taken in
+connection with the very clear illustration presented no difficulty
+should be experienced in understanding the proper installation, and
+mounting of this power plant. The bearers or beds should be 2 inches
+wide by 3 inches deep, preferably of laminated hard wood, and placed
+11-5/8 inches apart. They must be well braced. The six arms of the base
+of the motor are drilled for 3/8-inch bolts, and none but this size
+should he used.
+
+1. _Anchoring the Motor._ Put the bolts in from the bottom, with a large
+washer under the head of each so the head cannot cut into the wood. On
+every bolt use a castellated nut and a cotter pin, or an ordinary nut
+and a lock washer, so the bolt will not work loose. Always set motor in
+place and fasten before attaching any auxiliary apparatus, such as
+carburetor, etc.
+
+2. _Inspecting the Ignition-Switch Wires._ The wires leading from the
+ignition switch must be properly connected--one end to the motor body
+for ground, and the other end to the post on the breaker box of the
+magneto.
+
+3. _Filling the Radiator._ Be sure that the water from the radiator
+fills the cylinder jackets. Pockets of air may remain in the cylinder
+jackets even though the radiator may appear full. Turn the motor over a
+few times by hand after filling the radiator, and then add more water if
+the radiator will take it. The air pockets, if allowed to remain, may
+cause overheating and develop serious trouble when the motor is running.
+
+4. _Filling the Oil Reservoir._ Oil is admitted into the crank-case
+through the breather tube at the rear. It is well to strain all oil put
+into the crank-case. In filling the oil reservoir be sure to turn the
+handle on the oil sight-gauge till it is at right angles with the gauge.
+The oil sight-gauge is on the side of the lower half of the crank-case.
+Put in about 3 gallons of the best obtainable oil, Mobile B recommended.
+It is important to remember that the very best oil is none too good.
+
+5. _Oiling Exposed Moving Parts._ Oil all rocker-arm bearings before
+each flight. A little oil should be applied where the push rods pass
+through the stirrup straps.
+
+6. _Filling the Gasoline Tanks._ Be certain that all connections in the
+gasoline system are tight.
+
+7. _Turning on the Gasoline._ Open the cock leading from the gasoline
+tank to the carburetor.
+
+8. _Charging the Cylinders._ With the ignition switch OFF, prime the
+motor by squirting a little gasoline in each exhaust port and then turn
+the propeller backward two revolutions. Never open the exhaust valve by
+operating the rocker-arm by hand, as the push-rod is liable to come out
+of its socket in the cam follower and bend the rocker-arm when the motor
+turns over.
+
+9. _Starting the Motor by Hand._ Always retard the spark part way, to
+prevent back-firing, by pulling forward the wire attached to the breaker
+box. Failure to so retard the spark in starting may result in serious
+injury to the operator. Turn on the ignition switch with throttle partly
+open; give a quick, strong pull down and outward on the starting crank
+or propeller. As soon as the motor is started advance the spark by
+releasing the retard wire.
+
+10. _Oil Circulation._ Let the motor run at low speed for a few minutes
+in order to establish oil circulation in all bearings. With all parts
+functioning properly, the throttle may be opened gradually for warming
+up before flight.
+
+
+STANDARD S.A.E. ENGINE BED DIMENSIONS
+
+The Society of Automotive Engineers have made efforts to standardize
+dimensions of bed timbers for supporting power plant in an aeroplane.
+Owing to the great difference in length no standardization is thought
+possible in this regard. The dimensions recommended are as follows:
+
+ Distance between timbers 12 in. 14 in. 16 in.
+ Width of bed timbers 1-1/2 in. 1-3/4 in. 2 in.
+ Distance between centers of bolts 13-1/2 in. 15-3/4 in. 18 in.
+
+It will be evident that if any standard of this nature were adopted by
+engine builders that the designers of fuselage could easily arrange
+their bed timbers to conform to these dimensions, whereas it would be
+difficult to have them adhere to any standard longitudinal dimensions
+which are much more easily varied in fuselages than the transverse
+dimensions are. It, however, should be possible to standardize the
+longitudinal positions of the holding down bolts as the engine designer
+would still be able to allow himself considerable space fore-and-aft of
+the bolts.
+
+[Illustration: Fig. 148.--End Elevation of Hall-Scott A-7 Four-Cylinder
+Motor, with Installation Dimensions.]
+
+
+HALL-SCOTT ENGINE INSTALLATION
+
+[Illustration: Fig. 149.--Plan and Side Elevation of Hall-Scott A-7
+Four-Cylinder Airplane Engine, with Installation Dimensions.]
+
+The very thorough manner in which installation diagrams are prepared by
+the leading engine makers leaves nothing to the imagination. The
+dimensions of the Hall-Scott four-cylinder airplane engine are given
+clearly in our inch measurements with the metric equivalents at Figs.
+148 and 149, the former showing a vertical elevation while the latter
+has a plan view and side elevation. The installation of this engine in
+airplanes is clearly shown at Figs. 150 and 151, the former having the
+radiator installed at the front of the motor and having all exhaust
+pipes joined to one common discharge funnel, which deflects the gas over
+the top plane while the latter has the radiator placed vertically above
+the motor at the back end and has a direct exhaust gas discharge to the
+air.
+
+[Illustration: Fig. 150.
+
+CENSORED]
+
+[Illustration: Fig. 151.
+
+CENSORED]
+
+The dimensions of the six-cylinder Hall-Scott motor which is known as
+the type A-5 125 H. P. are given at Fig. 152, which is an end sectional
+elevation, and at Fig. 153, which is a plan view. The dimensions are
+given both in inch sizes and the metric equivalents. The appearance of
+a Hall-Scott six-cylinder engine installed in a fuselage is given at
+Fig. 154, while a diagram showing the location of the engine and the
+various pipes leading to the auxiliary groups is outlined at Fig. 155.
+The following instructions for installing the Hall-Scott power plant
+are reproduced from the instruction book issued by the maker.
+Operating instructions which are given should enable any good mechanic
+to make a proper installation and to keep the engine in good running
+condition.
+
+[Illustration: Fig. 152.
+
+CENSORED]
+
+
+FUEL SYSTEM INSTALLATION
+
+[Illustration: Fig. 153.--Plan View of Hall-Scott Type A-5 125
+Horse-Power Airplane Engine, Showing Installation Dimensions.]
+
+Gasoline giving the best results with this equipment is as follows:
+Gravity 58-62 deg. Baume A. Initial boiling point--Richmond method--102
+deg. Fahr. Sulphur .014. Calorimetric bomb test 20610 B. T. U. per pound.
+If the gasoline tank is placed in the fuselage below the level of the
+carburetor, a hand pump must be used to maintain air pressure in gas
+tank to force the gasoline to the carburetor. After starting the engine
+the small auxiliary air pump upon the engine will maintain sufficient
+pressure. A-7a and A-5a engines are furnished with a new type auxiliary
+air pump. This should be frequently oiled and care taken so no grit or
+sand will enter which might lodge between the valve and its seat, which
+would make it fail to operate properly. An air relief valve is furnished
+with each engine. It should be screwed into the gas tank and properly
+regulated to maintain the pressure required. This is done by screwing
+the ratchet on top either up or down. If two tanks are used in a plane
+one should be installed in each tank. All air pump lines should be
+carefully gone over quite frequently to ascertain if they are tight.
+Check valves have to be placed in these lines. In some cases the
+gasoline tank is placed above the engine, allowing it to drain by
+gravity to the carburetor. When using this system there should be a drop
+of not less than two feet from the lowest portion of the gasoline tank
+to the upper part of the carburetor float chamber. Even this height
+might not be sufficient to maintain the proper volume of gasoline to the
+carburetor at high speeds. Air pressure is advised upon all tanks to
+insure the proper supply of gasoline. When using gravity feed without
+air pressure be sure to vent the tank to allow circulation of air. If
+gravity tank is used and the engine runs satisfactorily at low speeds
+but cuts out at high speeds the trouble is undoubtedly due to
+insufficient height of the tank above the carburetor. The tank should be
+raised or air pressure system used.
+
+[Illustration: Fig. 154.--Three-Quarter View of Hall-Scott Type A-5 125
+Horse-Power Six-Cylinder Engine, with One of the Side Radiators Removed
+to Show Installation in Standard Fuselage.]
+
+[Illustration: Fig. 155.--Diagram Showing Proper Installation of
+Hall-Scott Type A-5 125 Horse-Power Engine with Pressure Feed Fuel
+Supply System.]
+
+
+IGNITION SWITCHES
+
+Two "DIXIE" switches are furnished with each engine. Both of these
+should be installed in the pilot's seat, one controlling the R. H., and
+the other the L. H. magneto. By shorting either one or the other it can
+be quickly determined if both magnetos, with their respective
+spark-plugs, are working correctly. Care should be taken not to use
+spark-plugs having _special extensions or long protruding points_. Plugs
+giving best results are extremely small with short points.
+
+
+WATER SYSTEMS
+
+A temperature gauge should be installed in the water pipe, coming
+directly from the cylinder nearest the propeller (note illustration
+above). This instrument installed in the radiator cap has not always
+given satisfactory results. This is especially noticeable when the water
+in the radiator becomes low, not allowing it to touch the bulb on the
+moto-meter. For ordinary running, it should not indicate over 150
+degrees Fahr. In climbing tests, however, a temperature of 160 degrees
+Fahr. can be maintained without any ill effects upon the engine. In case
+the engine becomes overheated, the indicator will register above 180
+degrees Fahr., in which case it should be stopped immediately.
+Overheating is most generally caused by retarded spark, excessive carbon
+in the cylinders, insufficient lubrication, improperly timed valves,
+lack of water, clogging of water system in any way which would obstruct
+the free circulation of the water.
+
+Overheating will cause the engine to knock, with possible damaging
+results. Suction pipes should be made out of thin tubing, and run within
+a quarter or an eighth of an inch of each other, so that when a hose is
+placed over the two, it will not be possible to suck together. This is
+often the case when a long rubber hose is used, which causes
+overheating. Radiators should be flushed out and cleaned thoroughly
+quite often. A dirty radiator may cause overheating.
+
+When filling the radiator it is very important to remove the plug on top
+of the water pump until water appears. This is to avoid air pockets
+being formed in the circulating system, which might not only heat up the
+engine, but cause considerable damage. All water pump hoses and
+connections should be tightly taped and shellacked after the engine is
+properly installed in the plane. The greatest care should be taken when
+making engine installation _not_ to use smaller inside diameter hose
+connection than water pump suction end casting. One inch and a quarter
+inside diameter should be used on A-7 and A-5 motors, while nothing less
+than one inch and a half inside diameter hose or tubing on all A-7a and
+A-5a engines. It is further important to have light spun tubing, void of
+any sharp turns, leads from pump to radiator and cylinder water outlet
+to radiator. In other words, the water circulation through the engine
+must be as little restricted as possible. Be sure no light hose is used,
+that will often suck together when engine is started. To thoroughly
+drain the water from the entire system, open the drain cock at the
+lowest side of the water pump.
+
+
+PREPARATIONS TO START ENGINE
+
+Always replenish gasoline tanks through a strainer which is clean. This
+strainer must catch all water and other impurities in the gasoline. Pour
+at least three gallons of fresh oil into the lower crank-case. Oil all
+rocker arms through oilers upon rocker arm housing caps. Be sure
+radiators are filled within one inch of the top.
+
+After all the parts are oiled, and the tanks filled, the following must
+be looked after before starting: See if crank-shaft flange is tight on
+shaft. See if propeller bolts are tight and evenly drawn up. See if
+propeller bolts are wired. See if propeller is trued up to within 1/8".
+
+Every four days the magnetos should be oiled if the engine is in daily
+use.
+
+Every month all cylinder hold-down nuts should be gone over to ascertain
+if they are tight. (Be sure to recotter nuts.)
+
+See if magnetos are bolted on tight and wired.
+
+See if magneto cables are in good condition.
+
+See if rocker arm tappets have a .020" clearance from valve stem when
+valve is seated.
+
+See if tappet clamp screws are tight and cottered.
+
+See if all gasoline, oil, water pipes and connections are in perfect
+condition.
+
+Air on gas line should be tested for leaks.
+
+Pump at least three pounds air pressure into gasoline tank.
+
+After making sure that above rules have been observed, test compression
+of cylinders by turning propeller.
+
+"DO NOT FORGET TO SHORT BOTH MAGNETOS"
+
+Be sure all compression release and priming cocks do not leak
+compression. If they do, replace same with a new one immediately, as
+this might cause premature firing.
+
+Open priming cocks and squirt some gasoline into each.
+
+Close cocks.
+
+Open compression release cocks.
+
+Open throttle slightly.
+
+If using Berling magnetos they should be three-quarters advanced.
+
+If all the foregoing directions have been carefully followed, the engine
+is ready for starting.
+
+In cranking engine either by starting crank, or propeller, it is
+essential to throw it over compression quickly.
+
+Immediately upon starting, close compression release cocks.
+
+When engine is running, advance magnetos.
+
+After it has warmed up, short one magneto and then the other, to be sure
+both magnetos and spark-plugs are firing properly. If there is a miss,
+the fouled plug must be located and cleaned. There is a possibility that
+the jets in the carburetor are stopped up. If this is the case, do not
+attempt to clean same with any sharp instrument. If this is done, it
+might change the opening in the jets, thus spoiling the adjustment. Jets
+and nozzles should be blown out with air or steam.
+
+An open intake or exhaust valve, which might have become sluggish or
+stuck from carbon, might cause trouble. Be sure to remedy this at once
+by using a little coal-oil or kerosene on same, working the valve by
+hand until it becomes free. We recommend using graphite on valve stems
+mixed with oil to guard against sticking or undue wear.
+
+
+INSTALLING ROTARY AND RADIAL CYLINDER ENGINES
+
+[Illustration: Fig. 156.--Diagram Defining Installation of Gnome
+"Monosoupape" Motor in Tractor Biplane. Note Necessary Piping for Fuel,
+Oil, and Air Lines.]
+
+When rotary engines are installed simple steel stamping or "spiders,"
+are attached to the fuselage to hold the fixed crank-shaft. Inasmuch as
+the motor projects clear of the fuselage proper there is plenty of room
+back of the front spider plate to install the auxiliary parts such as
+the oil pump, air pump and ignition magneto and also the fuel and oil
+containers. The diagram given at Fig. 156 shows how a Gnome
+"monosoupape" engine is installed on the anchorage plates and it also
+outlines clearly the piping necessary to convey the oil and fuel and
+also the air-piping needed to put pressure on both fuel and oil tanks to
+insure positive supply of these liquids which may be carried in tanks
+placed lower than the motor in some installations. The diagram given at
+Figs. 157 and 158 shows other mountings of Gnome engines and are
+self-explanatory. The simple mounting possible when the Anzani
+ten-cylinder radial fixed type engine is used given at Fig. 159. The
+front end of the fuselage is provided with a substantial pressed steel
+plate having members projecting from it which may be bolted to the
+longerons. The bolts that hold the two halves of the crank-case together
+project through the steel plate and hold the engine securely to the
+front end of the fuselage.
+
+[Illustration: Fig. 157.--Showing Two Methods of Placing Propeller on
+Gnome Rotary Motor.]
+
+
+PRACTICAL HINTS TO LOCATE ENGINE TROUBLES
+
+[Illustration: Fig. 158.--How Gnome Rotary Motor May Be Attached to
+Airplane Fuselage Members.]
+
+One who is not thoroughly familiar with engine construction will seldom
+locate troubles by haphazard experimenting and it is only by a
+systematic search that the cause can be discovered and the defects
+eliminated. In this chapter the writer proposes to outline some of the
+most common power-plant troubles and to give sufficient advice to enable
+those who are not thoroughly informed to locate them by a logical
+process of elimination. The internal-combustion motor, which is the
+power plant of all gasoline automobiles as well as airplanes, is
+composed of a number of distinct groups, which in turn include distinct
+components. These various appliances are so closely related to each
+other that defective action of any one may interrupt the operation of
+the entire power plant. Some of the auxiliary groups are more necessary
+than others and the power plant will continue to operate for a time even
+after the failure of some important parts of some of the auxiliary
+groups. The gasoline engine in itself is a complete mechanism, but it
+is evident that it cannot deliver any power without some means of
+supplying gas to the cylinders and igniting the compressed gas charge
+after it has been compressed in the cylinders. From this it is patent
+that the ignition and carburetion systems are just as essential parts of
+the power plant as the piston, connecting rod, or cylinder of the motor.
+The failure of either the carburetor or igniting means to function
+properly will be immediately apparent by faulty action of the power
+plant.
+
+[Illustration: Fig. 159.--How Anzani Ten-Cylinder Radial Engine is
+Installed to Plate Securely Attached to Front End of Tractor Airplane
+Fuselage.]
+
+To insure that the motor will continue to operate it is necessary to
+keep it from overheating by some form of cooling system and to supply
+oil to the moving parts to reduce friction. The cooling and lubrication
+groups are not so important as carburetion and ignition, as the engine
+would run for a limited period of time even should the cooling system
+fail or the oil supply cease. It would only be a few moments, however,
+before the engine would overheat if the cooling system was at fault, and
+the parts seize if the lubricating system should fail. Any derangement
+in the carburetor or ignition mechanism would manifest itself at once
+because the engine operation would be affected, but a defect in the
+cooling or oiling system would not be noticed so readily.
+
+The careful aviator will always inspect the motor mechanism before
+starting on a trip of any consequence, and if inspection is carefully
+carried out and loose parts tightened it is seldom that irregular
+operation will be found due to actual breakage of any of the components
+of the mechanism. Deterioration due to natural causes matures slowly,
+and sufficient warning is always given when parts begin to wear so
+satisfactory repairs may be promptly made before serious derangement or
+failure is manifested.
+
+
+A TYPICAL ENGINE STOPPAGE ANALYZED
+
+Before describing the points that may fail in the various auxiliary
+systems it will be well to assume a typical case of engine failure and
+show the process of locating the trouble in a systematic manner by
+indicating the various steps which are in logical order and which could
+reasonably be followed. In any case of engine failure the ignition
+system, motor compression, and carburetor should be tested first. If the
+ignition system is functioning properly one should determine the amount
+of compression in all cylinders and if this is satisfactory the
+carbureting group should be tested. If the ignition system is working
+properly and there is a decided resistance in the cylinders when the
+propeller is turned, proving that there is good compression, one may
+suspect the carburetor.
+
+[Illustration: Fig. 160.--Side Elevation of Thomas 135 Horse-Power
+Airplane Engine, Giving Important Dimensions.]
+
+If the carburetor appears to be in good condition, the trouble may be
+caused by the ignition being out of time, which condition is possible
+when the magneto timing gear or coupling is attached to the armature
+shaft by a taper and nut retention instead of the more positive key or
+taper-pin fastening. It is possible that the inlet manifold may be
+broken or perforated, that the exhaust valve is stuck on its seat
+because of a broken or bent stem, broken or loose cam, or failure of the
+cam-shaft drive because the teeth are stripped from the engine shaft or
+cam-shaft gears; or because the key or other fastening on either gear
+has failed, allowing that member to turn independently of the shaft to
+which it normally is attached. The gasoline feed pipe may be clogged or
+broken, the fuel supply may be depleted, or the shut-off cock in the
+gasoline line may have jarred closed. The gasoline filter may be filled
+with dirt or water which prevents passage of the fuel.
+
+[Illustration: Fig. 161.--Front Elevation of Thomas-Morse 135
+Horse-Power Aeromotor, Showing Main Dimensions.]
+
+The defects outlined above, except the failure of the gasoline supply,
+are very rare, and if the container is found to contain fuel and the
+pipe line to be clear to the carburetor, it is safe to assume the
+vaporizing device is at fault. If fuel continually runs out of the
+mixing chamber the carburetor is said to be flooded. This condition
+results from failure of the shut-off needle to seat properly or from a
+punctured hollow metal float or a gasoline-soaked cork float. It is
+possible that not enough gasoline is present in the float chamber. If
+the passage controlled by the float-needle valve is clogged or if the
+float was badly out of adjustment, this contingency would be probable.
+When the carburetor is examined, if the gasoline level appears to be at
+the proper height, one may suspect that a particle of lint, or dust, or
+fine scale, or rust from the gasoline tank has clogged the bore of the
+jet in the mixing chamber.
+
+If the ignition system and carburetor appear to be in good working
+order, and the hand crank shows that there is no compression in one or
+more of the cylinders, it means some defect in the valve system. If the
+engine is a multiple-cylinder type and one finds poor compression in all
+of the cylinders it may be due to the rare defect of improper valve
+timing. This may be caused by a gear having altered its position on the
+cam-shaft or crank-shaft, because of a sheared key or pin having
+permitted the gear to turn about half of a revolution and then having
+caught and held the gear in place by a broken or jagged end so that
+cam-shaft would turn, but the valves open at the wrong time. If but one
+of the cylinders is at fault and the rest appear to have good
+compression the trouble may be due to a defective condition either
+inside or outside of that cylinder. The external parts may be inspected
+easily, so the following should be looked for: a broken valve, a warped
+valve-head, broken valve-springs, sticking or bent valve-stems, dirt
+under valve-seat, leak at valve-chamber cap or spark-plug gasket.
+Defective priming cock, cracked cylinder head (rarely occurs), leak
+through cracked spark-plug insulation, valve-plunger stuck in the
+guide, lack of clearance between valve-stem end and top of plunger
+caused by loose adjusting screw which has worked up and kept the valve
+from seating. The faulty compression may be due to defects inside the
+motor. The piston-head may be cracked (rarely occurs), piston rings may
+be broken, the slots in the piston rings may be in line, the rings may
+have lost their elasticity or have become gummed in the grooves of the
+piston, or the piston and cylinder walls may be badly scored by a loose
+wrist pin or by defective lubrication. If the motor is a type with a
+separate head it is possible the gasket or packing between the cylinder
+and combustion chamber may leak, either admitting water to the cylinder
+or allowing compression to escape.
+
+[Illustration: Fig. 162.--Front and Side Elevations of Sturtevant
+Airplane Engine, Giving Principal Dimensions to Facilitate
+Installation.]
+
+
+CONDITIONS THAT CAUSE FAILURE OF IGNITION SYSTEM
+
+If the first test of the motor had showed that the compression was as it
+should be and that there were no serious mechanical defects and there
+was plenty of gasoline at the carburetor, this would have demonstrated
+that the ignition system was not functioning properly. If a battery is
+employed to supply current the first step is to take the spark-plugs out
+of the cylinders and test the system by turning over the engine by hand.
+If there is no spark in any of the plugs, this may be considered a
+positive indication that there is a broken main current lead from the
+battery, a defective ground connection, a loose battery terminal, or a
+broken connector. If none of these conditions are present, it is safe to
+say that the battery is no longer capable of delivering current. While
+magneto ignition is generally used on airplane engines, there is apt to
+be some development of battery ignition, especially on engines equipped
+with electric self-starters which are now being experimented with. The
+spark-plugs may be short circuited by cracked insulation or carbon and
+oil deposits around the electrode. The secondary wires may be broken or
+have defective insulation which permits the current to ground to some
+metal part of the fuselage or motor. The electrodes of the spark-plug
+may be too far apart to permit a spark to overcome the resistance of the
+compressed gas, even if a spark jumps the air space, when the plug is
+laid on the cylinder.
+
+If magnetos are fitted as is usually the case at present and a spark is
+obtained between the points of the plug and that device or the wire
+leading to it from the magneto is in proper condition, the trouble is
+probably caused by the magneto being out of time. This may result if the
+driving gear is loose on the armature-shaft or crank-shaft, and is a
+rare occurrence. If no spark is produced at the plugs the secondary wire
+may be broken, the ground wire may make contact with some metallic
+portion of the chassis before it reaches the switch, the carbon
+collecting brushes may be broken or not making contact, the contact
+points of the make-and-break device may be out of adjustment, the wiring
+may be attached to wrong terminals, the distributor filled with metallic
+particles, carbon, dust or oil accumulations, the distributor contacts
+may not be making proper connection because of wear and there may be a
+more serious derangement, such as a burned out secondary winding or a
+punctured condenser.
+
+If the motor runs intermittently, _i.e._, starts and runs only a few
+revolutions, aside from the conditions previously outlined, defective
+operation may be due to seizing between parts because of insufficient
+oil or deficient cooling, too much oil in the crank-case which fouls the
+cylinder after the crank-shaft has revolved a few turns, and
+derangements in the ignition or carburetion systems that may be easily
+remedied. There are a number of defective conditions which may exist in
+the ignition group, that will result in "skipping" or irregular
+operation and the following points should be considered first: weak
+source of current due to worn out dry cells or discharged storage
+batteries; weak magnets in magneto, or defective contacts at magneto;
+dirt in magneto distributor or poor contact at collecting brushes. Dirty
+or cracked insulator at spark-plug will cause short circuit and can
+only be detected by careful examination. The following points should
+also be checked over when the plug is inspected: Excessive space between
+electrodes, points too close together, loose central electrodes, or
+loose point on plug body, soot or oil particles between electrodes, or
+on the surface of the insulator, cracked insulator, oil or water on
+outside of insulator. Short circuits in the condenser or internal wiring
+of induction coils or magnetos, which are fortunately not common, can
+seldom be remedied except at the factory where these devices were made.
+If an engine stops suddenly and the defect is in the ignition system the
+trouble is usually never more serious than a broken or loose wire. This
+may be easily located by inspecting the wiring at the terminals.
+Irregular operation or misfiring is harder to locate because the trouble
+can only be found after the many possible defective conditions have been
+checked over, one by one.
+
+
+COMMON DEFECTS IN FUEL SYSTEMS
+
+Defective carburetion often causes misfiring or irregular operation. The
+common derangement of the components of the fuel system that are common
+enough to warrant suspicion and the best methods for their location
+follows: First, disconnect the feed pipe from the carburetor and see if
+the gasoline flows freely from the tank. If the stream coming out of the
+pipe is not the full size of the orifice it is an indication that the
+pipe is clogged with dirt or that there is an accumulation of rust,
+scale, or lint in the strainer screens of the filter. It is also
+possible that the fuel shut-off valve may be wholly or partly closed. If
+the gasoline flows by gravity the liquid may be air bound in the tank,
+while if a pressure-feed system is utilized the tank may leak so that it
+does not retain pressure; the check valve retaining the pressure may be
+defective or the pipe conveying the air or gas under pressure to the
+tank may be clogged.
+
+If the gasoline flows from the pipe in a steady stream the carburetor
+demands examination. There may be dirt or water in the float chamber,
+which will constrict the passage between the float chamber and the spray
+nozzle, or a particle of foreign matter may have entered the nozzle and
+stopped up the fine holes therein. The float may bind on its guide, the
+needle valve regulating the gasoline-inlet opening in bowl may stick to
+its seat. Any of the conditions mentioned would cut down the gasoline
+supply and the engine would not receive sufficient quantities of gas.
+The air-valve spring may be weak or the air valve broken. The
+gasoline-adjusting needle may be loose and jar out of adjustment, or the
+air-valve spring-adjusting nuts may be such a poor fit on the stem that
+adjustments will not be retained. These instructions apply only to
+carburetors having air valves and mixture regulating means which are
+used only in rare instances in airplane work. Air may leak in through
+the manifold, due to a porous casting, or leaky joints in a built up
+form and dilute the mixture. The air-intake dust screen may be so
+clogged with dirt and lint that not enough air will pass through the
+mesh. Water or sediment in the gasoline will cause misfiring because the
+fuel feed varies when the water or dirt constricts the standpipe bore.
+
+It is possible that the carburetor may be out of adjustment. If clouds
+of black smoke are emitted at the exhaust pipe it is positive indication
+that too much gasoline is being supplied the mixture and the supply
+should be cut down by screwing in the needle valve on types where this
+method of regulation is provided, and by making sure that the fuel level
+is at the proper height, or that the proper nozzle is used in those
+forms where the spray nozzle has no means of adjustment. If the mixture
+contains too much air there will be a pronounced popping back in the
+carburetor. This may be overcome by screwing in the air-valve adjustment
+so the spring tension is increased or by slightly opening up the
+gasoline-supply regulation needle. When a carburetor is properly
+adjusted and the mixture delivered the cylinder burns properly, the
+exhaust gas will be clean and free from the objectionable odor present
+when gasoline is burned in excess.
+
+The character of combustion may be judged by the color of the flame
+which issues from it when the engine is running with an open throttle
+after nightfall. If the flame is red, it indicates too much gasoline. If
+yellowish, it shows an excess of air, while a properly proportioned
+mixture will be evidenced by a pronounced blue flame, such as given by a
+gas-stove burner.
+
+The Duplex Model O. D. Zenith carburetor used upon most of the six- and
+eight-cylinder airplane engines consists of a single float chamber, and
+a single air intake, joined to two separate and distinct spray nozzles,
+venturi and idling adjustments. It is to be noted that as the carburetor
+barrels are arranged side by side, both valves are mounted on the same
+shaft, and work in unison through a single operating lever. It is not
+necessary to alter their position. In order to make the engine idle
+well, it is essential that the ignition, especially the spark-plugs,
+should be in good condition. The gaskets between carburetor and
+manifold, and between manifold and cylinders should be absolutely
+air-tight. The adjustment for low speed on the carburetor is made by
+turning in or out the two knurled screws, placed one on each side of the
+float chamber. After starting the engine and allowing it to become
+thoroughly warmed, one side of the carburetor should be adjusted so that
+the three cylinders it affects fire properly at low speed. The other
+side should be adjusted in the same manner until all six cylinders fire
+perfectly at low speed. As the adjustment is changed on the knurled
+screw a difference in the idling of the engine should be noticed. If the
+engine begins to run evenly or speeds up it shows that the mixture
+becomes right in its proportion.
+
+Be sure the butterfly throttle is closed as far as possible by screwing
+out the stop screw which regulates the closed position for idling. Care
+should be taken to have the butterfly held firmly against this stop
+screw at all times while idling engine. If three cylinders seem to run
+irregularly after changing the position of the butterfly, still another
+adjustment may have to be made with the knurled screw. Unscrewing this
+makes the mixture leaner. Screwing in closes off some of the air supply
+to the idling jet, making it richer. After one side has been made to
+idle satisfactorily repeat the same procedure with the opposite three
+cylinders. In other words, each side should be idled independently to
+about the same speed.
+
+Remember that the main jet and compensating jet have no appreciable
+effect on the idling of the engine. The idling mixture is drawn directly
+through the opening determined by the knurled screw and enters the
+carburetor barrel through the small hole at the edge of each butterfly.
+This is called the priming hole and is only effective during idling.
+Beyond that point the suction is transferred to the main jet and
+compensator, which controls the power of the engine beyond the idling
+position of the throttle.
+
+
+DEFECTS IN OILING SYSTEMS
+
+While troubles existing in the ignition or carburetion groups are
+usually denoted by imperfect operation of the motor, such as lost power,
+and misfiring, derangements of the lubrication or cooling systems are
+usually evident by overheating, diminution in engine capacity, or noisy
+operation. Overheating may be caused by poor carburetion as much as by
+deficient cooling or insufficient oiling. When the oiling group is not
+functioning as it should the friction between the motor parts produces
+heat. If the cooling system is in proper condition, as will be evidenced
+by the condition of the water in the radiator, and the carburetion group
+appears to be in good condition, the overheating is probably caused by
+some defect in the oiling system.
+
+The conditions that most commonly result in poor lubrication are:
+Insufficient oil in the engine crank-case or sump, broken or clogged oil
+pipes, screen at filter filled with lint or dirt, broken oil pump, or
+defective oil-pump drive. The supply of oil may be reduced by a
+defective inlet or discharge-check valve at the mechanical oiler or worn
+pumps. A clogged oil passage or pipe leading to an important bearing
+point will cause trouble because the oil cannot get between the working
+surfaces. It is well to remember that much of the trouble caused by
+defective oiling may be prevented by using only the best grades of
+lubricant, and even if all parts of the oil system are working properly,
+oils of poor quality will cause friction and overheating.
+
+
+DEFECTS IN COOLING SYSTEMS OUTLINED
+
+Cooling systems are very simple and are not liable to give trouble as a
+rule if the radiator is kept full of clean water and the circulation is
+not impeded. When overheating is due to defective cooling the most
+common troubles are those that impede water circulation. If the radiator
+is clogged or the piping of water jackets filled with rust or sediment
+the speed of water circulation will be slow, which will also be the case
+if the water pump or its driving means fail. Any scale or sediment in
+the water jackets or in the piping or radiator passages will reduce the
+heat conductivity of the metal exposed to the air, and the water will
+not be cooled as quickly as though the scale was not present.
+
+The rubber hose often used in making the flexible connections demanded
+between the radiator and water manifolds of the engine may deteriorate
+inside and particles of rubber hang down that will reduce the area of
+the passage. The grease from the grease cups mounted on the pump-shaft
+bearing to lubricate that member often finds its way into the water
+system and rots the inner walls of the rubber hose, this resulting in
+strips of the partly decomposed rubber lining hanging down and
+restricting the passage. The cooling system is prone to overheat after
+antifreezing solutions of which calcium chloride forms a part have been
+used. This is due to the formation of crystals of salt in the radiator
+passages or water jackets, and these crystals can only be dissolved by
+suitable chemical means, or removed by scraping when the construction
+permits.
+
+Overheating is often caused by some condition in the fuel system that
+produces too rich or too lean mixture. Excess gasoline may be supplied
+if any of the following conditions are present: Bore of spray nozzle or
+standpipe too large, auxiliary air-valve spring too tight, gasoline
+level too high, loose regulating valve, fuel-soaked cork float,
+punctured sheet-metal float, dirt under float control shut-off valve or
+insufficient air supply because of a clogged air screen. If pressure
+feed is utilized there may be too much pressure in the tank, or the
+float controlled mechanism operating the shut-off in the float bowl of
+the carburetor may not act quickly enough.
+
+
+SOME CAUSES OF NOISY OPERATION
+
+There are a number of power-plant derangements which give positive
+indication because of noisy operation. Any knocking or rattling sounds
+are usually produced by wear in connecting rods or main bearings of the
+engine, though sometimes a sharp metallic knock, which is very much the
+same as that produced by a loose bearing, is due to carbon deposits in
+the cylinder heads, or premature ignition due to advanced spark-time
+lever. Squeaking sounds invariably indicate dry bearings, and whenever
+such a sound is heard it should be immediately located and oil applied
+to the parts thus denoting their dry condition. Whistling or blowing
+sounds are produced by leaks, either in the engine itself or in the gas
+manifolds. A sharp whistle denotes the escape of gas under pressure and
+is usually caused by a defective packing or gasket that seals a portion
+of the combustion chamber or that is used for a joint as the exhaust
+manifold. A blowing sound indicates a leaky packing in crank-case.
+Grinding noises in the motor are usually caused by the timing gears and
+will obtain if these gears are dry or if they have become worn. Whenever
+a loud knocking sound is heard careful inspection should be made to
+locate the cause of the trouble. Much harm may be done in a few minutes
+if the engine is run with loose connecting rod or bearings that would be
+prevented by taking up the wear or looseness between the parts by some
+means of adjustment.
+
+
+BRIEF SUMMARY OF HINTS FOR STARTING ENGINE
+
+First make sure that all cylinders have compression. To ascertain this,
+open pet cocks of all cylinders except the one to be tested, crank over
+motor and see that a strong opposition to cranking is met with once in
+two revolutions. If motor has no pet cocks, crank and notice that
+oppositions are met at equal distances, two to every revolution of the
+starting crank in a four-cylinder motor. If compression is lacking,
+examine the parts of the cylinder or cylinders at fault in the following
+order, trying to start the motor whenever any one fault is found and
+remedied. See that the valve push rods or rocker arms do not touch valve
+stems for more than approximately 1/2 revolution in every 2 revolutions,
+and that there is not more than .010 to .020 inch clearance between them
+depending on the make of the motor. Make sure that the exhaust valve
+seats. To determine this examine the spring and see that it is connected
+to the valve stem properly. Take out valve and see that there is no
+obstruction, such as carbon, on its seat. See that valve works freely in
+its guide. Examine inlet valve in same manner. Listen for hissing sound
+while cranking motor for leaks at other places.
+
+Make sure that a spark occurs in each cylinder as follows: If magneto or
+magneto and battery with non-vibrating coil is used: Disconnect wire
+from spark-plug, hold end about 1/8 inch from cylinder or terminal of
+spark-plug. Have motor cranked briskly and see if spark occurs. Examine
+adjustment of interrupter points. See that wires are placed correctly
+and not short circuited. Take out spark-plug and lay it on the cylinder,
+being careful that base of plug only touches the cylinder and that
+ignition wire is connected. Have motor cranked briskly and see if spark
+occurs. Check timing of magneto and see that all brushes are making
+contact.
+
+See if there is gasoline in the carburetor. See that there is gasoline
+in the tank. Examine valve at tank. Prime carburetor and see that spray
+nozzle passage is clear. Be sure throttle is open. Prime cylinders by
+putting about a teaspoonful of gasoline in through pet cock or
+spark-plug opening. Adjust carburetor if necessary.
+
+
+LOCATION OF ENGINE TROUBLES MADE EASY
+
+The following tabulation has been prepared and originated by the writer
+to outline in a simple manner the various troubles and derangements that
+interfere with efficient internal-combustion engine action. The parts
+and their functions are practically the same in all gas or gasoline
+engines of the four-cycle type, and the general instructions given apply
+just as well to all hydro-carbon engines, even if the parts differ in
+form materially. The essential components are clearly indicated in the
+many part sectional drawings in this book so they may be easily
+recognized. The various defects that may materialize are tabulated in a
+manner that makes for ready reference, and the various defective
+conditions are found opposite the part affected, and under a heading
+that denotes the main trouble to which the others are contributing
+causes. The various symptoms denoting the individual troubles outlined
+are given to facilitate their recognition in a positive manner.
+
+Brief note is also made of the remedies for the restoration of the
+defective part or condition. It is apparent that a table of this
+character is intended merely as a guide, and it is a compilation of
+practically all the known troubles that may materialize in gas-engine
+operation. While most of the defects outlined are common enough to
+warrant suspicion, they will never exist in an engine all at the same
+time, and it will be necessary to make a systematic search for such of
+those as exist.
+
+To use the list advantageously, it is necessary to know one main trouble
+easily recognized. For example, if the power plant is noisy, look for
+the possible troubles under the head of Noisy Operation; if it lacks
+capacity, the derangement will undoubtedly be found under the head of
+Lost Power. It is assumed in all cases that the trouble exists in the
+power plant or its components, and not in the auxiliary members of the
+ignition, carburetion, lubrication, or cooling systems. The novice and
+student will readily recognize the parts of the average aviation engine
+by referring to the very complete and clearly lettered illustrations of
+mechanism given in many parts of this treatise.
+
+
+LOST POWER AND OVERHEATING
+
+ ------------------+------------------+------------------+--------------------
+ PART AFFECTED |NATURE OF TROUBLE | SYMPTOMS AND | REMEDY
+ | | EFFECTS |
+ ------------------+------------------+------------------+--------------------
+ Water Pipe Joint. |Loose. |Loss of water, |Tighten bolts,
+ | |heating. |replace gaskets.
+ | | |
+ Spark Plug. |Leakage in |Loss of power. |Replace insulation
+ |threads, |Hissing caused by |if defective, screw
+ |insulation, |escaping gas. |down tighter.
+ |packing. | |
+ | | |
+ Compression |Leak in threads. |Loss of power. |Tighten if loose.
+ Release Cock. |Leak in fitting. |Whistling or |Grind fitting to
+ | |hissing. |new seating in
+ | | |body.
+ | | |
+ Combustion |Crack or blowhole.|Loss of compres- |Fill by welding.
+ Chamber. |Roughness. Carbon |sion. Preignition.|Smooth out
+ |deposits. Sharp | |roughness. Scrape
+ |edges. | |out or dissolve
+ | | |carbon.
+ | | |
+ Valve Chamber Cap.|Leak in threads. |Loss of compres- |Remove. Apply pipe
+ |Defective gasket. |sion. Hissing. |compound to threads
+ | | |and replace. Use
+ | | |new gasket or
+ | | |packing.
+ | | |
+ Valve Head. |Warped. Scored or |Loss of compres- |True up in lathe.
+ |pitted. Carbon- |sion. |Grind to seat.
+ |ized. Covered with| |Scrape off. Smooth
+ |scale. Loose on | |with emery cloth.
+ |stem (two-piece | |Tighten by
+ |valves only). | |riveting.
+ | | |
+ Valve Seat. |Warped or pitted. |Loss of compres- |Use reseating
+ |Covered with car- |sion. |reamer. Clean off
+ |bon. Foreign mat- | |and grind valve to
+ |ter between valve | |seat.
+ |and seat. | |
+ | | |
+ Valve Stem. |Covered with |Valve does not |Clean with emery
+ |scale. Bent. Bind-|close. Loss of |cloth; straighten.
+ |ing in guide. |compression. |True up and smooth
+ |Stuck in guide. | |off. free with
+ | | |kerosene.
+ | | |
+ Valve Stem Guide. |Burnt or rough. |Valve may stick. |Clean out hole.
+ |Loose in valve |Action irregular. |Screw in tighter.
+ |chamber. | |
+ | | |
+ Valve Spring. |Weak or broken. |Valve does not |
+ | |close. |
+ | | |
+ Valve Operating |Loose in guide. |Valve action poor.|Replace with new.
+ Plunger. |Too much clearance|Lift insufficient.|Adjust screw closer.
+ |between valve | |
+ |stem. | |
+ | | |
+ Valve Lift Ad- |Threads stripped. |Poor valve action.|Replace with new.
+ justing Screw. |Too near valve. | |Adjust with proper
+ |Too far from | |reference to valve
+ |valve. | |stem.
+ | | |
+ Valve Lift Cam. |Worn cam contour. |Not enough valve |Replace with new.
+ |Loose on shaft. |lift. Will not |Replace pins or
+ |Out of time. |lift valve. Valve |keys. Set to open
+ | |opens at wrong |properly.
+ | |time. |
+ | | |
+ Cam-shaft. |Sprung or twisted.|Valves out of |Straighten.
+ | |time. |
+ | | |
+ Cam-shaft Bushing.|Worn. |Not enough valve |Replace.
+ | |lift. |
+ | | |
+ Cam-shaft Drive |Loose on shaft. |Irregular valve |Fasten securely.
+ Gear. |Out of time. Worn |action. |Time properly.
+ |or broken teeth. | |Replace with new.
+ | | |
+ Cam Fastenings. |Worn or broken. |Valves out of |Replace with new.
+ | |time. |
+ | | |
+ Cylinder Wall. |Scored, gas leaks.|Poor compression. |Grind out bore.
+ |Poor lubrication |Overheating. |Repair oiling
+ |causes friction. | |system.
+ | | |
+ Piston. |Binds in cylinder.|Overheating. Poor |Lap off excess
+ |Walls scored. Worn|compression. |metal. Replace with
+ |out of round. | |new.
+ | | |
+ Piston Rings. |Loss of spring. |Loss of compres- |Peen ring or
+ |Loose in grooves. |sion. Gas blows |replace. Fit new
+ |Scored. Worn or |by. |rings. Grind smooth.
+ |broken. Slots in | |Replace. Turn slots
+ |line. | |apart.
+ | | |
+ |Carbon in grooves.|Overheating be- |Remove deposits.
+ |Insufficient open-|cause of friction.|File slot. Grind or
+ |ing. Binding on | |lap to fit cylinder
+ |cylinder. | |bore.
+ | | |
+ Wristpin. |Loose, scores |Loss of compres- |Fasten securely.
+ |cylinder. |sion. |Replace cylinder if
+ | | |groove is deep.
+ | | |
+ Crank-shaft. |Scored or rough on|Overheating be- |Smooth up.
+ |journals. Sprung. |cause of friction.|Straighten.
+ | | |
+ Crank Bearings. |Adjusted too |Overheating be- |Adjust freely, clean
+ Main Bearings. |tight. Defective |cause of friction.|out oil holes and
+ |oiling. Brasses | |enlarge oil grooves.
+ |burned. | |
+ | | |
+ Oil Sump. |Insufficient oil. |Overheating. |Replenish supply.
+ |Poor lubricant. | |Use best oil. Wash
+ |Dirty oil. | |out with kerosene;
+ | | |put in clean oil.
+ | | |
+ Water Space. Water|Clogged with sedi-|Overheating. |Dissolve foreign
+ Pipes. |ment or scale. | |matter and remove.
+ | | |
+ Piston Head. |Cracked (rare). |Loss of compres- |Weld by autogenous
+ |Carbon deposits. |sion. Preignition.|process. Scrape off
+ | | |carbon accumula-
+ | | |tions.
+ ------------------+------------------+------------------+--------------------
+
+
+NOISY OPERATION OF POWER PLANT
+
+ ------------------+------------------+------------------+--------------------
+ PART AFFECTED |NATURE OF TROUBLE | CHARACTER OF | REMEDY
+ | | NOISE |
+ ------------------+------------------+------------------+--------------------
+ Compression Re- |Leakage. |Hissing. |Previously given.
+ lease Cock. | | |
+ | | |
+ Spark Plug. |Leakage. |Hissing. |Previously given.
+ | | |
+ Valve Chamber Cap.|Leakage. |Hiss or whistle. |Previously given.
+ | | |
+ Combustion |Carbon deposits. |Knocking. |Previously given.
+ Chamber. | | |
+ | | |
+ Inlet Valve Seat. |Defects previously|Popping in carbu- |Previously given.
+ |given. |retor. |
+ | | |
+ Valve Head. |Loose on stem. |Clicking. |Previously given.
+ | | |
+ Valve Stem. Valve |Wear or looseness.|Rattle or click- |Previously given.
+ Stem Guide. | |ing. |
+ | | |
+ Inlet Valve. |Closes too late. |Blowback in carbu-|Previously given.
+ |Opens too early. |retor. |
+ | | |
+ Valve Spring. |Weak or broken. |Blowback in carbu-|Previously given.
+ | |retor. |
+ | | |
+ Cylinder Casting. |Retaining bolts |Sharp metallic |Tighten bolts. Round
+ |loose. Piston |knock. |edges of piston
+ |strikes at upper | |top.
+ |end. | |
+ | | |
+ Cylinder Wall. |Scored. |Hissing. |Previously given.
+ | | |
+ Valve Stem |Too much. |Clicking. Blowback|Previously given.
+ Clearance. |Too little (inlet |in carburetor. |
+ |valve). | |
+ | | |
+ Valve Operating |Looseness. |Rattle or click- |Previously given.
+ Plunger. Plunger | |ing. |
+ Guide. | | |
+ | | |
+ Timing Gears. |Loose on fasten- |Metallic knock. |Previously given.
+ |ings. Worn teeth. |Rattle. Grinding. |
+ | | |
+ Cylinder or |No oil, or poor |Grinding. |Repair oil system.
+ Piston. |lubricant. | |
+ | | |
+ Cam. |Loose on shaft. |Metallic knock. |Previously given.
+ |Worn contour. | |
+ | | |
+ Cam-shaft Bearing.|Looseness or wear.|Slight knock. |Previously given.
+ | | |
+ Cam Fastening. |Looseness. |Clicking. |Previously given.
+ | | |
+ Piston. |Binding in cylin- |Grinding or dull |Previously given.
+ |der. Worn oval, |squeak. Dull |
+ |causes side slap |hammering. |
+ |in cylinder. | |
+ | | |
+ Piston Head. |Carbon deposits. |Knocking. |Previously given.
+ | | |
+ Piston Rings. |Defective oiling. |Squeaking. Hiss- |Previously given.
+ |Leakage. Binding |ing. Grinding. |
+ |in cylinder. | |
+ | | |
+ Wrist-pin. |Loose in piston. |Dull metallic |Replace with new
+ |Worn. |knock. |member.
+ | | |
+ Connecting Rod. |Wear in upper |Distinct knock. |Adjust or replace.
+ |bushing. Wear at | |Scrape and fit. Use
+ |crank-pin. Side | |longer wrist-pin
+ |play in piston. | |bushing.
+ | | |
+ Crank Bearings. |Looseness. Exces- |Metallic knock. |Refit bearings.
+ |sive end play. |Intermittent |Longer bushings
+ |Binding, fitted |knock. Squeaking. |needed. Insert shims
+ |too tight. | |to allow more play.
+ | | |
+ Main Bearings. |Looseness. Defec- |Metallic knock. |Fit brasses closer
+ |tive lubrication. |Squeaking. |to shaft. Clean out
+ | | |oil holes and
+ | | |grooves.
+ | | |
+ Connecting Rod |Loose. |Sharp knock. |Tighten.
+ Bolts. Main | | |
+ Bearing Bolts. | | |
+ | | |
+ Crank-shaft. |Defective oiling. |Squeaking. |Previously given.
+ | | |
+ Engine Base. |Loose on frame. |Sharp pounding. |Tighten bolts.
+ | | |
+ Lower Half Crank- |Bolts loose. |Knocking. |Tighten bolts.
+ case. | | |
+ | | |
+ Fly-wheel. |Loose on crank- |Very sharp knock. |Tighten retention
+ |shaft. | |bolts or fit new
+ | | |keys.
+ | | |
+ Oil Sump. |Oil level too low.|Grinding and |Replenish with best
+ |Poor lubricant. |squeak in all |cylinder oil.
+ | |bearings. |
+ | | |
+ Valve Plunger Re- |Looseness. |Clicking. |Tighten nuts.
+ tention Stirrups. | | |
+ | | |
+ Fan. |Blade loose. Blade|Clicking or |Tighten. Bend back.
+ |strikes cooler. |rattle. |
+ | | |
+ Exhaust Pipe |Leakage. |Sharp hissing. |Tighten or use new
+ Joints. | | |gasket.
+ | | |
+ Crank-case |Leakage. |Blowing sound. |Use new packing.
+ Packing. | | |Tighten bolts.
+ | | |
+ Water Pipe. |Leaks. Loss of |Pounding because |Previously given.
+ |water. Clogged |engine heats. |
+ |with sediment. | |
+ | | |
+ Water Jacket. |Clogged with sedi-|Knocking because |Dissolve scale and
+ |ment. Walls |engine heats. |flush out water
+ |covered with | |space with water
+ |scale. | |under pressure.
+--------------------+------------------+------------------+--------------------
+
+
+"SKIPPING" OR IRREGULAR OPERATION
+
+ ------------------+------------------+------------------+--------------------
+ PART AFFECTED |NATURE OF TROUBLE | SYMPTOMS AND | REMEDY
+ | | EFFECTS |
+ ------------------+------------------+------------------+--------------------
+ Compression Relief|Leak in threads or|Dilutes mixture |Screw down tighter.
+ Cock. |spigot. |with air, causes |Grind spigot to seat
+ | |blowback. |with emery.
+ | | |
+ Spark-Plug. |Leak in threads. |Dilutes mixture. |Screw down tighter.
+ |Defective gasket. |Allows short |Replace with new.
+ |Cracked insulator.|circuit. No spark.|Set points 1/64"
+ |Points too near. | |apart for magneto,
+ |Points covered | |1/32" for battery
+ |with carbon. Too | |spark.
+ |much air gap. | |
+ | | |
+ Valve Chamber Cap.|Leak in threads. |Dilutes mixture by|Previously given.
+ |Defective gasket. |allowing air to |
+ | |enter cylinder on |
+ | |suction stroke. |
+ | | |
+ Combustion |Carbon deposits. |Preignition. |Scrape out.
+ Chamber. | | |
+ | | |
+ Valve Head. |Warped or pitted. |Dilutes charge |Previously given.
+ |Loose on stem. |with poor air or |
+ | |gas. |
+ | | |
+ Valve Stem. |Binding in guide. |Irregular valve |Previously given.
+ |Sticking. |action. |
+ | | |
+ Valve Seat. |Scored or warped. |Gas leak, poor |Previously given.
+ |Cracked. Covered |mixture. Poor com-|
+ |with scale. Dirt |pression. Valve |
+ |under valve. |will not close. |
+ | | |
+ Induction Pipe. |Leak at joints. |Mixture diluted |Stop all leaks.
+ |Crack or blowhole.|with excess air. |
+ | | |
+ Inlet Valve. |Closes too late. |Blowback in carbu-|Time properly.
+ |Opens too early. |retor. |
+ | | |
+ Exhaust Valve. |Opens too late. |Retention of burnt|Time properly.
+ |Closes too early. |gas dilutes |
+ | |charge. |
+ | | |
+ Valve Stem Guide. |Bent or carbon- |Causes valve to |Previously given.
+ |ized. |stick. |
+ | | |
+ Inlet Valve Stem |Worn, stem loose. |Air drawn in on |Bush guide or use
+ Guide. | |suction thins gas.|new member.
+ | | |
+ Valve Spring. |Weakened or |Irregular action. |Use new spring.
+ |broken. | |
+ | | |
+ Valve Stem |Too little. Too |Valve will not |Adjust gap .009"
+ Clearance. |much. |shut. Valve opens |inlet, .010"
+ | |late, closes |exhaust.
+ | |early. |
+ Valve Spring |Broken. |Releases spring. |Replace.
+ Collar Key. | | |
+ | | |
+ Cam. |Worn cam contour. |Valve lift re- |Previously given.
+ |Loose on shaft. |duced. Does not |
+ |Out of time. |lift valve. Valves|
+ | |operate at wrong |
+ | |time. |
+ | | |
+ Cam-shaft Bearing.|Looseness or wear.|Valve timing |Replace.
+ | |altered. Valve |
+ | |lift decreased. |
+ | | |
+ Cam-shaft. |Twisted. |Valves out of |Previously given.
+ | |time. |
+ | | |
+ Cam Fastening. |Worn or broken. |Valve action |Replace with new.
+ | |irregular. |
+ | | |
+ Valve Operating |Loose in guide. |Alters valve |Replace with new.
+ Plunger. | |timing. |
+ | | |
+ Valve Plunger |Wear in bore. |Alters valve |Replace or bush.
+ Guide. |Loose on engine |timing. |Fasten securely.
+ |base. | |
+ | | |
+ Timing Gears. |Not properly |Valves out of |Retime properly.
+ |meshed. Loose on |time. Valves do |Fasten to shaft.
+ |shaft. |not operate. |
+ | | |
+ Piston. |Walls scored. |Leakage of gas. |Smooth up if
+ | | |possible.
+ | | |
+ Piston Head. |Carbon deposits. |Cause premature |Previously given.
+ |Crack or blowhole |ignition. |
+ |(rare). | |
+ | | |
+ Piston Rings. |No spring. Loose |Leakage weakens |Previously given.
+ |in grooves. Worn |suction. |
+ |or broken. | |
+ | | |
+ Cylinder Wall. |Scored by wrist- |Gas leaks by. Poor|Previously given.
+ |pin. Scored by |suction. |
+ |lack of oil. | |
+ ------------------+------------------+------------------+--------------------
+
+
+IGNITION SYSTEM TROUBLES ONLY
+
+
+_Motor Will Not Start or Starts Hard_
+
+ Loose Battery Terminal.
+ Magneto Ground Wire Shorted.
+ Magneto Defective (No Spark at Plugs).
+ Broken Spark Plug Insulation.
+ Carbon Deposits or Oil Between Plug Points.
+ Spark-Plug Points Too Near Together or Far Apart.
+ Wrong Cables to Plugs.
+ Short Circuited Secondary Cable.
+ Broken Secondary Cable.
+ Dry Battery Weak. }
+ Storage Battery Discharged. } Battery Systems
+ Poor Contact at Timer. } Only.
+ Timer Points Dirty. }
+ Poor Contact at Switch. }
+ Primary Wires Broken, or Short Circuited. } Battery and
+ Battery Grounded in Metal Container. } Coil Ignition
+ Battery Connectors Broken or Loose. } System Only.
+ Timer Points Out of Adjustment. }
+ Defects in Induction Coil. }
+ Ignition Timing Wrong, Spark Too Late or Too Early.
+ Defective Platinum Points in Breaker Box (Magneto).
+ Points Not Separating.
+ Broken Contact Maker Spring.
+ No Contact at Secondary Collector Brush.
+ Platinum Contact Points Burnt or Pitted.
+ Contact Breaker Bell Crank Stuck.
+ Fiber Bushing in Bell Crank Swollen.
+ Short Circuiting Spring Always in Contact.
+ Dirt or Water in Magneto Casing.
+ Oil in Contact Breaker.
+ Oil Soaked Brush and Collector Ring.
+ Distributor Filled with Carbon Particles.
+
+
+_Motor Stops Without Warning_
+
+ Broken Magneto Carbon Brush.
+ Broken Lead Wire.
+ Broken Ground Wire.
+ Battery Ignition Systems.
+ Water on High Tension Magneto Terminal.
+ Main Secondary Cable Burnt Through by Hot Exhaust
+ Pipe (Transformer Coil, Magneto Systems).
+ Particle of Carbon Between Spark Plug Points.
+ Magneto Short Circuited by Ground Wire.
+ Magneto Out of Time, Due to Slipping Drive.
+ Water or Oil in Safety Spark Gap (Multi-cylinder Magneto).
+ Magneto Contact Breaker or Timer Stuck in Retard
+ Position.
+ Worn Fiber Block in Magneto Contact Breaker.
+ Binding Fiber Bushing in Contact Breaker Bell Crank.
+ Spark Advance Rod or Wire Broken.
+ Contact Breaker Parts Stuck.
+
+
+_Motor Runs Irregularly or Misfires_
+
+ Loose Wiring or Terminals.
+ Broken Spark-Plug Insulator.
+ Spark-Plug Points Sooted or Oily.
+ Wrong Spark Gap at Plug Points.
+ Leaking Secondary Cable.
+ Prematurely Grounded Primary Wire.
+ Batteries Running Down (Battery Ignition only).
+ Poor Adjustment of Contact Points at Timer.
+ Wire Broken Inside of Insulation.
+ Loose Platinum Points in Magneto.
+ Weak Contact Spring.
+ Broken Collector Brush.
+ Dirt in Magneto Distributor Casing or Contact Breaker.
+ Worn Fiber Block or Cam Plate in Magneto.
+ Worn Cam or Contact Roll in Timer (Battery System
+ only).
+ Dirty Oil in Timer.
+ Sticking Coil Vibrators.
+ Coil Vibrator Points Pitted.
+ Oil Soaked Magneto Winding.
+ Punctured Magneto or Coil Winding.
+ Distributor Contact Segments Rough.
+ Sulphated Storage Battery Terminals.
+ Weak Magnets in Magneto.
+ Poor Contact at Magneto Contact Breaker Points.
+
+
+DEFECTS IN ELECTRICAL SYSTEM COMPONENTS
+
+To further simplify the location of electrical system faults it is
+thought desirable to outline the defects that can be present in the
+various parts of the individual devices comprising the ignition system.
+If an airplane engine is provided with magneto ignition solely, as most
+engines are at the present time, no attention need be paid to such items
+as storage or dry batteries, timer or induction coil. There seems to be
+some development in the direction of battery ignition so it has been
+considered desirable to include components of these systems as well as
+the almost universally used magneto group. Spark-plugs, wiring and
+switches are needed with either system.
+
+
+SPARK-PLUGS
+
+ DEFECT TROUBLE CAUSED REMEDY
+ Insulation cracked. Plug inoperative. New insulation.
+ Insulation oil soaked. Cylinder misfires. Clean.
+ Carbon deposits. Short circuited spark. Remove.
+ Insulator loose. Cylinder misfires. Tighten.
+ Gasket broken. Gas leaks by. New gasket.
+ Electrode loose on shell. Cylinder misfires. Tighten.
+ Wire loose in insulator. Cylinder misfires. Tighten.
+ Air gap too close. Short circuits spark. Set correctly.
+ Air gap too wide. Spark will not jump. Set points 1/32"
+ apart.
+ Loose terminal. Cylinder may misfire. Tighten.
+ Plug loose in cylinder. Gas leaks. Tighten.
+ Mica insulation oil soaked. Short circuits spark. Replace.
+
+
+MAGNETO
+
+ DEFECT TROUBLE CAUSED REMEDY
+ Dirty oil in distributor. Engine misfires. Clean.
+ Metal dust in distributor. Engine misfires. Clean.
+ Brushes not making contact. Current cannot pass. Strengthen
+ spring.
+ Distributor segments worn. Engine misfires. Secure even
+ bearing.
+ Collecting brush broken. Engine misfires. New brush.
+ Distributing brush broken. Engine misfires. New brush.
+ Oil soaked winding. Engine misfires. Clean.
+ Magnets loose on pole Engine misfires. Tighten screws.
+ pieces.
+ Armature rubs. Engine misfires. Repair bearings.
+ Bearings worn. Noisy. Replace.
+ Magnets weak. Weak spark. Recharge.
+ Contact breaker points Engine misfires. Clean.
+ pitted.
+ Breaker points out of Engine misfires. Reset.
+ adjustment.
+ Defective winding (rare). No spark. Replace.
+ Punctured condenser (rare). Weak or no spark. Replace.
+ Driving gear loose. Noise. Tighten.
+ Magneto armature out of Spark will not fire Retime.
+ time. charge.
+ Magneto loose on base. Misfiring and noisy. Tighten.
+ Contact breaker cam worn. Misfiring. Replace.
+ Fibre shoe or rolls worn Misfiring. Replace.
+ (Bosch).
+ Fibre bushing binding in Misfiring. Ream slightly.
+ contact lever (Bosch).
+ Contact lever return spring No spark. Replace.
+ broken.
+ Contact lever return spring Misfiring. Replace.
+ weak.
+ Ground wire grounded. No spark. Insulate.
+ Ground wire broken. Engine will not stop. Connect up.
+ Safety spark gap dirty. No spark. Clean.
+ Fused metal in spark gap. No spark. Remove.
+ Safety spark gap points too Misfiring. Set properly.
+ close.
+ Loose distributor terminals. Misfiring. Tighten.
+ Contact breaker sticks. No spark control. Remove and clean
+ bearings.
+ Magneto switch short- No spark. Insulate.
+ circuited.
+ Magneto switch open circuit. No engine stop. Restore contact.
+
+
+STORAGE BATTERY
+
+ DEFECT TROUBLE CAUSED REMEDY
+ Electrolyte low. Weak current. Replenish with
+ distilled water.
+ Loose terminals. Misfiring. Tighten.
+ Sulphated terminals. Misfiring. Clean thoroughly
+ and coat with
+ vaseline.
+ Battery discharged. Misfiring or no spark. New charge.
+ Electrolyte weak. Weak current. Bring to proper
+ specific gravity.
+ Plates sulphated. Poor capacity. Special slow charge.
+ Sediment or mud in bottom. Weak current. Clean out.
+ Active material loose in Poor capacity. New plates.
+ grids.
+ Moisture or acid on top of Shorts terminals. Remove.
+ cells.
+ Plugged vent cap. Buckles cell jars. Make vent hole.
+ Cracked vent cap. Acid spills out. New cap.
+ Cracked cell jar. Electrolyte runs out. New jar.
+
+DRY CELL BATTERY
+
+ DEFECT TROUBLE CAUSED REMEDY
+ Broken wires. No current. New wires.
+ Loose terminals. Misfiring. Tighten.
+ Weak cell (7 amperes or Misfiring. New cells.
+ less).
+ Cells in contact. Short circuit. Separate and
+ insulate.
+ Water in battery box. Short circuit. Dry out.
+
+
+TIMER
+
+ DEFECT TROUBLE CAUSED REMEDY
+ Contact segments worn or Misfiring. Grind down
+ pitted. smooth.
+ Platinum points pitted. Misfiring. Smooth with oil
+ stone.
+ Dirty oil or metal dust in Misfiring. Clean out.
+ interior.
+ Worn bearing. Misfiring. Replace.
+ Loose terminals. Misfiring. Tighten.
+ Worn revolving contact Misfiring. Replace.
+ brush.
+ Out of time. Irregular spark. Reset.
+
+
+INDUCTION COIL
+
+ DEFECT TROUBLE CAUSED REMEDY
+ Loose terminals. Misfiring. Tighten.
+ Broken connections. No spark. Make new joints.
+ Vibrators out of adjustment. Misfiring. Readjust.
+ Vibrator points pitted. Misfiring. Clean.
+ Defective condenser } rare. No spark. Send to maker
+ Defective winding } for repairs.
+ Poor contact at switch. Misfiring. Tighten.
+ Broken internal wiring. No spark. Replace.
+ Poor coil unit. One cylinder affected. Replace.
+
+
+WIRING
+
+ DEFECT TROUBLE CAUSED REMEDY
+ Loose terminals anywhere. Misfiring. Tighten.
+ Broken plug wire. One cylinder will not Replace.
+ fire.
+ Broken timer wire. One coil will not buzz. Replace.
+ Broken main battery wire. } No spark. Replace.
+ Broken battery ground wire.}
+ Broken magneto ground wire. Engine will not stop. Replace.
+ Chafed insulation anywhere.} Misfiring. Insulate.
+ Short circuit anywhere. }
+
+
+CARBURETION SYSTEM FAULTS SUMMARIZED
+
+
+_Motor Starts Hard or Will Not Start_
+
+ No Gasoline in Tank.
+ No Gasoline in Carburetor Float Chamber.
+ Tank Shut-Off Closed.
+ Clogged Filter Screen.
+ Fuel Supply Pipe Clogged.
+ Gasoline Level Too Low.
+ Gasoline Level Too High (Flooding).
+ Bent or Stuck Float Lever.
+ Loose or Defective Inlet Manifold.
+ Not Enough Gasoline at Jet.
+ Cylinders Flooded with Gas.
+ Fuel Soaked Cork Float (Causes Flooding).
+ Water in Carburetor Spray Nozzle.
+ Dirt in Float Chamber.
+ Gas Mixture Too Lean.
+ Carburetor Frozen (Winter Only).
+
+
+_Motor Stops In Flight_
+
+ Gasoline Shut-Off Valve Jarred Closed.
+ Gasoline Supply Pipe Clogged.
+ No Gasoline in Tank.
+ Spray Nozzle Stopped Up.
+ Water in Spray Nozzle.
+ Particles of Carbon Between Spark-Plug Points.
+ Magneto Short Circuited by Ground in Wire.
+ Air Lock in Gasoline Pipe.
+ Broken Air Line or Leaky Tank (Pressure Feed System Only).
+ Fuel Supply Pipe Partially Clogged.
+ Air Vent in Tank Filler Cap Stopped Up (Gravity and Vacuum Feed
+ System).
+ Float Needle Valve Stuck.
+ Water or Dirt in Spray Nozzle.
+ Mixture Adjusting Needle Jarred Loose (Rotary Motors Only).
+
+
+_Motor Races, Will Not Throttle Down_
+
+ Air Leak in Inlet Piping.
+ Air Leak Through Inlet Valve Guides.
+ Control Rods Broken.
+ Defective Induction Pipe Joints.
+ Leaky Carburetor Flange Packing.
+ Throttle Not Closing.
+ Poor Slow Speed Adjustment (Zenith Carburetor).
+
+
+_Motor Misfires_
+
+ Carburetor Float Chamber Getting Dry.
+ Water or Dirt in Gasoline.
+ Poor Gasoline Adjustment (Rotary Motors).
+ Not Enough Gasoline in Float Chamber.
+ Too Much Gasoline, Carburetor Flooding.
+ Incorrect Jet or Choke (Zenith Carburetor).
+ Broken Cylinder Head Packing Between Cylinders.
+
+
+_Noisy Operation_
+
+ Popping or Blowing Back in Carburetor.
+ Incorrectly Timed Inlet Valves.
+ Inlet Valve Not Seating.
+ Defective Inlet Valve Spring.
+ Dirt Under Inlet Valve Seat.
+ Not Enough Gasoline (Open Needle Valve).
+ Muffler or Manifold Explosions.
+ Mixture Not Exploding Regularly.
+ Exhaust Valve Sticking.
+ Dirt Under Exhaust Valve Seat.
+
+
+
+
+CHAPTER XI
+
+ Tools for Adjusting and Erecting--Forms of Wrenches--Use and
+ Care of Files--Split Pin Removal and Installation--Complete
+ Chisel Set--Drilling Machines--Drills, Reamers, Taps and Dies--
+ Measuring Tools--Micrometer Calipers and Their Use--Typical Tool
+ Outfits--Special Hall-Scott Tools--Overhauling Airplane Engines
+ --Taking Engine Down--Defects in Cylinders--Carbon Deposits,
+ Cause and Prevention--Use of Carbon Scrapers--Burning Out Carbon
+ with Oxygen--Repairing Scored Cylinders--Valve Removal and
+ Inspection--Reseating and Truing Valves--Valve Grinding
+ Processes--Depreciation in Valve Operating System--Piston
+ Troubles--Piston Ring Manipulation--Fitting Piston Rings--
+ Wrist-Pin Wear--Inspection and Refitting of Engine Bearings--
+ Scraping Brasses to Fit--Fitting Connecting Rods--Testing for
+ Bearing Parallelism--Cam-Shafts and Timing Gears--Precautions in
+ Reassembling Parts.
+
+
+TOOLS FOR ADJUSTING AND ERECTING
+
+[Illustration: Fig. 163.--Practical Hand Tools Useful in Dismantling and
+Repairing Airplane Engines.]
+
+A very complete outfit of small tools, some of which are furnished as
+part of the tool equipment of various engines are shown in group at Fig.
+163. This group includes all of the tools necessary to complete a very
+practical kit and it is not unusual for the mechanic who is continually
+dismantling and erecting engines to possess even a larger assortment
+than indicated. The small bench vise provided is a useful auxiliary that
+can be clamped to any convenient bench or table or even fuselage
+longeron in an emergency and should have jaws at least three inches wide
+and capable of opening four or five inches. It is especially useful in
+that it will save trips to the bench vises, as it has adequate capacity
+to handle practically any of the small parts that need to be worked on
+when making repairs. A blow torch, tinner's snips and soldering copper
+are very useful in sheet metal work and in making any repairs requiring
+the use of solder. The torch can be used in any operation requiring a
+source of heat. The large box wrench shown under the vise is used for
+removing large special nuts and sometimes has one end of the proper size
+to fit the valve chamber cap. The piston ring removers are easily made
+from thin strips of sheet metal securely brazed or soldered to a light
+wire handle. These are used in sets of three for removing and applying
+piston rings in a manner to be indicated. The uses of the wrenches,
+screw drivers, and pliers shown are known to all and the variety
+outlined should be sufficient for all ordinary work of restoration. The
+wrench equipment is very complete, including a set of open end
+S-wrenches to fit all standard bolts, a spanner wrench, socket or box
+wrenches for bolts that are inaccessible with the ordinary type,
+adjustable end wrenches, a thin monkey wrench of medium size, a bicycle
+wrench for handling small nuts and bolts, a Stillson wrench for pipe and
+a large adjustable monkey wrench for the stubborn fastenings of large
+size.
+
+Four different types of pliers are shown, one being a parallel jaw type
+with size cutting attachment, while the other illustrated near it is a
+combination parallel jaw type adapted for use on round work as well as
+in handling flat stock. The most popular form of pliers is the
+combination pattern shown beneath the socket wrench set. This is made of
+substantial drop forgings having a hinged joint that can be set so that
+a very wide opening at the jaws is possible. These can be used on round
+work and for wire cutting as well as for handling flat work. Round nose
+pliers are very useful also.
+
+A very complete set of files, including square, half round, mill, flat
+bastard, three-cornered and rat tail are also necessary. A hacksaw frame
+and a number of saws, some with fine teeth for tubing and others with
+coarser teeth for bar or solid stock will be found almost indispensable.
+A complete punch and chisel set should be provided, samples of which are
+shown in the group while the complete outfit is outlined in another
+illustration. A number of different forms and sizes of chisels are
+necessary, as one type is not suitable for all classes of work. The
+adjustable end wrenches can be used in many places where a monkey wrench
+cannot be fitted and where it will be difficult to use a wrench having a
+fixed opening. The Stillson pipe wrench is useful in turning studs,
+round rods, and pipes that cannot be turned by any other means. A
+complete shop kit must necessarily include various sizes for Stillson
+and monkey wrenches, as no one size can be expected to handle the wide
+range of work the engine repairman must cope with. Three sizes of each
+form of wrench can be used, one, a 6 inch, is as small as is needed
+while, a 12 inch tool will handle almost any piece of pipe or nut used
+in engine construction.
+
+Three or four sizes of hammers should be provided, according to
+individual requirement, these being small riveting, medium and
+heavyweight machinist's hammers. A very practical tool of this nature
+for the repair shop can be used as a hammer, screw driver or pry iron.
+It is known as the "Spartan" hammer and is a tool steel drop forging in
+one piece having the working surfaces properly hardened and tempered
+while the metal is distributed so as to give a good balance to the head
+and a comfortable grip to the handle. The hammer head provides a
+positive and comfortable T-handle when the tool is used as a screw
+driver or "tommy" bar. Machinist's hammers are provided with three types
+of heads, these being of various weights. The form most commonly used is
+termed the "ball pein" on account of the shape of the portion used for
+riveting. The straight pein is just the same as the cross pein, except
+that in the latter the straight portion is at right angles to the hammer
+handle, while in the former it is parallel to that member.
+
+
+FORMS OF WRENCHES
+
+Wrenches have been made in infinite variety and there are a score or
+more patterns of different types of adjustable socket and off-set
+wrenches. The various wrench types that differ from the more
+conventional monkey wrenches or those of the Stillson pattern are shown
+at Fig. 164. The "perfect handle" is a drop forged open end form
+provided with a wooden handle similar to that used on a monkey wrench in
+order to provide a better grip for the hand. The "Saxon" wrench is a
+double alligator form, so called because the jaws are in the form of a
+V-groove having one side of the V plain, while the other is serrated in
+order to secure a tight grip on round objects. In the form shown, two
+jaws of varying sizes are provided, one for large work, the other to
+handle the smaller rods. One of the novel features in connection with
+this wrench is the provision of a triple die block in the centre of the
+handle which is provided with three most commonly used of the standard
+threads including 5/16-inch-18, 3/8-inch-16, and 1/2-inch-13. This is
+useful in cleaning up burred threads on bolts before they are replaced,
+as burring is unavoidable if it has been necessary to drive them out
+with a hammer. The "Lakeside" wrench has an adjustable pawl engaging
+with one of a series of notches by which the opening may be held in any
+desired position.
+
+[Illustration: Fig. 164.--Wrenches are Offered in Many Forms.]
+
+Ever since the socket wrench was invented it has been a popular form
+because it can be used in many places where the ordinary open end or
+monkey wrench cannot be applied owing to lack of room for the head of
+the wrench. A typical set which has been made to fit in a very small
+space is shown at D. It consists of a handle, which is nickel-plated and
+highly polished, a long extension bar, a universal joint and a number of
+case hardened cold drawn steel sockets to fit all commonly used standard
+nuts and bolt heads. Two screw-driver bits, one small and the other
+large to fit the handle, and a long socket to fit spark-plugs are also
+included in this outfit. The universal joint permits one to remove nuts
+in a position that would be inaccessible to any other form of wrench, as
+it enables the socket to be turned even if the handle is at one side of
+an intervening obstruction.
+
+The "Pick-up" wrench, shown at E, is used for spark-plugs and the upper
+end of the socket is provided with a series of grooves into which a
+suitable blade carried by the handle can be dropped. The handle is
+pivoted to the top of the socket in such a way that the blades may be
+picked up out of the grooves by lifting on the end of the handle and
+dropped in again when the handle is swung around to the proper point to
+get another hold on the socket. The "Miller" wrench shown at F, is a
+combination socket and open end type, made especially for use with
+spark-plugs. Both the open end and the socket are convenient. The
+"Handy" set shown at G, consists of a number of thin stamped wrenches of
+steel held together in a group by a simple clamp fitting, which enables
+either end of any one of the four double wrenches to be brought into
+play according to the size of the nut to be turned. The "Cronk" wrench
+shown at H, is a simple stamping having an alligator opening at one end
+and a stepped opening capable of handling four different sizes of
+standard nuts or bolt heads at the other. Such wrenches are very cheap
+and are worth many times their small cost, especially for fitting nuts
+where there is not sufficient room to admit the more conventional
+pattern. The "Starrett" wrench set, which is shown at I, consists of a
+ratchet handle together with an extension bar and universal joint, a
+spark-plug socket, a drilling attachment which takes standard square
+shank drills from 1/8-inch to 1/2-inch in diameter, a double ended
+screw-driver bit and several adjustments to go with the drilling
+attachment. Twenty-eight assorted cold drawn steel sockets similar in
+design to those shown at D, to fit all standard sizes of square and
+hexagonal headed nuts are also included. The reversible ratchet handle,
+which may be slipped over the extension bar or the universal joint and
+which is also adapted to take the squared end of any one of the sockets
+is exceptionally useful in permitting, as it does, the instant release
+of pressure when it is desired to swing the handle back to get another
+hold on the nut. The socket wrench sets are usually supplied in hard
+wood cases or in leather bags so that they may be kept together and
+protected against loss or damage. With a properly selected socket wrench
+set, either of the ratchet handle or T-handle form, any nut on the
+engine may be reached and end wrenches will not be necessary.
+
+
+USE AND CARE OF FILES
+
+Mention has been previously made of the importance of providing a
+complete set of files and suitable handles. These should be in various
+grades or degrees of fineness and three of each kind should be provided.
+In the flat and half round files three grades are necessary, one with
+coarse teeth for roughing, and others with medium and fine teeth for the
+finishing cuts. The round or rat tail file is necessary in filing out
+small holes, the half round for finishing the interior of large ones.
+Half round files are also well adapted for finishing surfaces of
+peculiar contour, such as the inside of bearing boxes, connecting rod
+and main bearing caps, etc. Square files are useful in finishing keyways
+or cleaning out burred splines, while the triangular section or
+three-cornered file is of value in cleaning out burred threads and
+sharp corners. Flat files are used on all plane surfaces.
+
+[Illustration: Fig. 165.--Illustrating Use and Care of Files.]
+
+The file brush shown at Fig. 165, A, consists of a large number of wire
+bristles attached to a substantial wood back having a handle of
+convenient form so that the bristles may be drawn through the
+interstices between the teeth of the file to remove dirt and grease. If
+the teeth are filled with pieces of soft metal, such as solder or
+babbitt, it may be necessary to remove this accumulation with a piece of
+sheet metal as indicated at Fig. 165, B. The method of holding a file
+for working on plain surfaces when it is fitted with the regular form of
+wooden handle is shown at C, while two types of handles enabling the
+mechanic to use the flat file on plain surfaces of such size that the
+handle type indicated at C, could not be used on account of interfering
+with the surface finished are shown at D. The method of using a file
+when surfaces are finished by draw filing is shown at E. This differs
+from the usual method of filing and is only used when surfaces are to be
+polished and very little metal removed.
+
+
+SPLIT PIN REMOVAL AND INSERTION
+
+One of the most widely used of the locking means to prevent nuts or
+bolts from becoming loose is the simple split pin, sometimes called a
+"cotter pin." These can be handled very easily if the special pliers
+shown at Fig. 166, A, are used. They have a curved jaw that permits of
+grasping the pin firmly and inserting it in the hole ready to receive
+it. It is not easy to insert these split pins by other means because the
+ends are usually spread out and it is hard to enter the pin in the hole.
+With the cotter pin pliers the ends may be brought close together and as
+the plier jaws are small the pin may be easily pushed in place. Another
+use of this plier, also indicated, is to bend over the ends of the split
+pin in order to prevent it from falling out. To remove these pins a
+simple curved lever, as shown at Fig. 166, B, is used. This has one end
+tapering to a point and is intended to be inserted in the eye of the
+cotter pin, the purchase offered by the handle permitting of ready
+removal of the pin after the ends have been closed by the cotter pin
+pliers.
+
+
+COMPLETE CHISEL SET
+
+[Illustration: Fig. 166.--Outlining Use of Cotter Pin Pliers, Spring
+Winder, and Showing Practical Outfit of Chisels.]
+
+A complete chisel set suitable for repair shop use is also shown at Fig.
+166. The type at C is known as a "cape" chisel and has a narrow cutting
+point and is intended to chip keyways, remove metal out of corners and
+for all other work where the broad cutting edge chisel, shown at D,
+cannot be used. The form with the wide cutting edge is used in chipping,
+cutting sheet metal, etc. At E, a round nose chisel used in making oil
+ways is outlined, while a similar tool having a pointed cutting edge and
+often used for the same purpose is shown at F. The centre punch depicted
+at G, is very useful for marking parts either for identification or for
+drilling. In addition to the chisels shown, a number of solid punches
+or drifts resembling very much that shown at E, except that the point is
+blunt should be provided to drive out taper pins, bolts, rivets, and
+other fastenings of this nature. These should be provided in the common
+sizes. A complete set of real value would start at 1/8-inch and increase
+by increments of 1/32-inch up to 1/2-inch. A simple spring winder is
+shown at Fig. 166, H, this making it possible for the repairman to wind
+coil springs, either on the lathe or in the vise. It will handle a
+number of different sizes of wire and can be set to space the coils as
+desired.
+
+
+DRILLING MACHINES
+
+[Illustration: Fig. 167.--Forms of Hand Operated Drilling Machines.]
+
+Drilling machines may be of two kinds, hand or power operated. For
+drilling small holes in metal it is necessary to run the drill fast,
+therefore the drill chuck is usually driven by gearing in order to
+produce high drill speed without turning the handle too fast. A small
+hand drill is shown at Fig. 167, A. As will be observed, the chuck
+spindle is driven by a small bevel pinion, which in turn, is operated by
+a large bevel gear turned by a crank. The gear ratio is such that one
+turn of the handle will turn the chuck five or six revolutions. A drill
+of this design is not suited for drills any larger than one-quarter
+inch. For use with drills ranging from one-eighth to three-eighths, or
+even half-inch the hand drill presses shown at C and D are used. These
+have a pad at the upper end by which pressure may be exerted with the
+chest in order to feed the drill into the work, and for this reason they
+are termed "breast drills." The form at C has compound gearing, the
+drill chuck being driven by the usual form of bevel pinion in mesh with
+a larger bevel gear at one end of a countershaft. A small helical spur
+pinion at the other end of this countershaft receives its motion from a
+larger gear turned by the hand crank. This arrangement of gearing
+permits of high spindle speed without the use of large gears, as would
+be necessary if but two were used. The form at D gives two speeds, one
+for use with small drills is obtained by engaging the lower bevel pinion
+with the chuck spindle and driving it by the large ring gear. The slow
+speed is obtained by shifting the clutch so that the top bevel pinion
+drives the drill chuck. As this meshes with a gear but slightly larger
+in diameter, a slow speed of the drill chuck is possible. Breast drills
+are provided with a handle screwed into the side of the frame, these
+are used to steady the drill press. For drilling extremely large holes
+which are beyond the capacity of the usual form of drill press the
+ratchet form shown at B, may be used or the bit brace outlined at E. The
+drills used with either of these have square shanks, whereas those used
+in the drill presses have round shanks. The bit brace is also used
+widely in wood work and the form shown is provided with a ratchet by
+which the bit chuck may be turned through only a portion of a revolution
+in either direction if desired.
+
+
+DRILLS, REAMERS, TAPS AND DIES
+
+In addition to the larger machine tools and the simple hand tools
+previously described, an essential item of equipment of any engine or
+plane repair shop, even in cases where the ordinary machine tools are
+not provided, is a complete outfit of drills, reamers, and threading
+tools. Drills are of two general classes, the flat and the twist drills.
+The flat drill has an angle between cutting edges of about 110 degrees
+and is usually made from special steel commercially known as drill rod.
+
+A flat drill cannot be fed into the work very fast because it removes
+metal by a scraping, rather than a cutting process. The twist drill in
+its simplest form is cylindrical throughout the entire length and has
+spiral flutes which are ground off at the end to form the cutting lip
+and which also serve to carry the metal chips out of the holes. The
+simplest form of twist drill used is shown at Fig. 168, C, and is known
+as a "chuck" drill, because it must be placed in a suitable chuck to
+turn it. A twist drill removes metal by cutting and it is not necessary
+to use a heavy feed as the drill will tend to feed itself into the work.
+
+[Illustration: Fig. 168.--Forms of Drills Used in Hand and Power
+Drilling Machines.]
+
+Larger drills than 3/4-inch are usually made with a tapered shank as
+shown at Fig. 168, B. At the end of the taper a tongue is formed which
+engages with a suitable opening in the collet, as the piece used to
+support the drill is called. The object of this tongue is to relieve
+the tapered portion of the drill from the stress of driving by
+frictional contact alone, as this would not turn the drill positively
+and the resulting slippage would wear the socket, this depreciation
+changing the taper and making it unfit for other drills. The tongue is
+usually proportioned so it is adequate to drive the drill under any
+condition. A small keyway is provided in the collet into which a
+tapering key of flat stock may be driven against the end of the tongue
+to drive the drill from the spindle. A standard taper for drill shanks
+generally accepted by the machine trade is known as the Morse and is a
+taper of five-eighths of an inch to the foot. The Brown and Sharp form
+tapers six-tenths of an inch to the foot. Care must be taken, therefore,
+when purchasing drills and collets, to make sure that the tapers
+coincide, as no attempt should be made to run a Morse taper in a Brown
+and Sharp collet, or vice versa.
+
+Sometimes cylindrical drills have straight flutes, as outlined at Fig.
+168, A. Such drills are used with soft metals and are of value when the
+drill is to pass entirely through the work. The trouble with a drill
+with spiral flutes is that it will tend to draw itself through as the
+cutting lips break through. This catching of the drill may break it or
+move the work from its position. With a straight flute drill the cutting
+action is practically the same as with the flat drill shown at Fig. 168,
+E and F.
+
+If a drill is employed in boring holes through close-grained, tough
+metals, as wrought or malleable iron and steel, the operation will be
+facilitated by lubricating the drill with plenty of lard oil or a
+solution of soda and water. Either of these materials will effectually
+remove the heat caused by the friction of the metal removed against the
+lips of the drill, and the danger of heating the drill to a temperature
+that will soften it by drawing the temper is minimized. In drilling
+large or deep holes it is good practice to apply the lubricating medium
+directly at the drill point. Special drills of the form shown at Fig.
+168, B, having a spiral oil tube running in a suitably formed channel,
+provides communication between the point of the drill and a suitable
+receiving hole on a drilled shank. The oil is supplied by a pump and its
+pressure not only promotes positive circulation and removal of heat, but
+also assists in keeping the hole free of chips. In drilling steel or
+wrought iron, lard oil applied to the point of the drill will facilitate
+the drilling, but this material should never be used with either brass
+or cast iron.
+
+The sizes to be provided depend upon the nature of the work and the
+amount of money that can be invested in drills. It is common practice to
+provide a set of drills, such as shown at Fig. 169, which are carried in
+a suitable metal stand, these being known as number drills on account
+of conforming to the wire gauge standards. Number drills do not usually
+run higher than 5/16 inch in diameter. Beyond this point drills are
+usually sold by the diameter. A set of chuck drills, ranging from 3/8 to
+3/4 inch, advancing by 1/32 inch, and a set of Morse taper shank drills
+ranging from 3/4 to 1-1/4 inches, by increments of 1/16 inch, will be
+all that is needed for the most pretentious repair shop, as it is
+cheaper to bore holes larger than 1-1/4 inches with a boring tool than
+it is to carry a number of large drills in stock that would be used very
+seldom, perhaps not enough to justify their cost.
+
+[Illustration: Fig. 169.--Useful Set of Number Drills, Showing Stand for
+Keeping These in an Orderly Manner.]
+
+In grinding drills, care must be taken to have the lips of the same
+length, so that they will form the same angle with the axis. If one lip
+is longer than the other, as shown in the flat drill at Fig. 168, E, the
+hole will be larger than the drill size, and all the work of cutting
+will come upon the longest lip. The drill ends should be symmetrical, as
+shown at Fig. 168, F.
+
+[Illustration: Fig. 170.--Illustrating Standard Forms of Hand and
+Machine Reamers.]
+
+It is considered very difficult to drill a hole to an exact diameter,
+but for the most work a variation of a few thousandths of an inch is of
+no great moment. Where accuracy is necessary, holes must be reamed out
+to the required size. In reaming, a hole is drilled about 1/32 inch
+smaller than is required, and is enlarged with a cutting tool known as
+the reamer. Reamers are usually of the fluted form shown at Fig. 170, A.
+Tools of this nature are not designed to remove considerable amounts of
+metal, but are intended to augment the diameter of the drill hole by
+only a small fraction of an inch. Reamers are tapered slightly at the
+point in order that they will enter the hole easily, but the greater
+portion of the fluted part is straight, all cutting edges being
+parallel. Hand reamers are made in either the straight or taper forms,
+that at A, Fig. 170, being straight, while B has tapering flutes. They
+are intended to be turned by a wrench similar to that employed in
+turning a tap, as shown at Fig. 172, C. The reamer shown at Fig. 170,
+C, is a hand reamer. The form at D has spiral flutes similar to a twist
+drill, and as it is provided with a taper shank it is intended to be
+turned by power through the medium of a suitable collet.
+
+As the solid reamers must become reduced in size when sharpened, various
+forms of inserted blade reamers have been designed. One of these is
+shown at E, and as the cutting surfaces become reduced in diameter it is
+possible to replace the worn blades with others of proper size.
+Expanding reamers are of the form shown at F. These have a bolt passing
+through that fits into a tapering hole in the interior of the split
+reamer portion of the tool. If the hole is to be enlarged a few
+thousandths of an inch, it is possible to draw up on the nut just above
+the squared end of the shank, and by drawing the tapering wedge farther
+into the reamer body, the cutting portion will be expanded and will cut
+a larger hole.
+
+Reamers must be very carefully sharpened or there will be a tendency
+toward chattering with a consequent production of a rough surface. There
+are several methods of preventing this chattering, one being to separate
+the cutting edges by irregular spaces, while the most common method, and
+that to be preferred on machine reamers, is to use spiral flutes, as
+shown at Fig. 170, D. Special taper reamers are made to conform to the
+various taper pin sizes which are sometimes used in holding parts
+together in an engine. A taper of 1/16 inch per foot is intended for
+holes where a pin, once driven in, is to remain in place. When it is
+desired that the pin be driven out, the taper is made steeper, generally
+1/4 inch per foot, which is the standard taper used on taper pins.
+
+[Illustration: Fig. 171.--Tools for Thread Cutting.]
+
+When threads are to be cut in a small hole, it will be apparent that it
+will be difficult to perform this operation economically on a lathe,
+therefore when internal threading is called for, a simple device known
+as a "tap" is used. There are many styles of taps, all conforming to
+different standards. Some are for metric or foreign threads, some
+conform to the American standards, while others are used for pipe and
+tubing. Hand taps are the form most used in repair shops, these being
+outlined at Fig. 171, A and B. They are usually sold in sets of three,
+known respectively as taper, plug, and bottoming. The taper tap is the
+one first put into the hole, and is then followed by the plug tap which
+cuts the threads deeper. If it is imperative that the thread should be
+full size clear to the bottom of the hole, the third tap of the set,
+which is straight-sided, is used. It would be difficult to start a
+bottoming tap into a hole because it would be larger in diameter at its
+point than the hole. The taper tap, as shown at A, Fig. 171, has a
+portion of the cutting lands ground away at the point in order that it
+will enter the hole. The manipulation of a tap is not hard, as it does
+not need to be forced into the work, as the thread will draw it into
+the hole as the tap is turned. The tapering of a tap is done so that no
+one thread is called upon to remove all of the metal, as for about half
+way up the length of the tap each succeeding thread is cut a little
+larger by the cutting edge until the full thread enters the hole. Care
+must be taken to always enter a tap straight in order to have the thread
+at correct angles to the surface.
+
+In cutting external threads on small rods or on small pieces, such as
+bolts and studs, it is not always economical to do this work in the
+lathe, especially in repair work. Dies are used to cut threads on pieces
+that are to be placed in tapped holes that have been threaded by the
+corresponding size of tap. Dies for small work are often made solid, as
+shown at Fig. 171, C, but solid dies are usually limited to sizes below
+1/2 inch. Sometimes the solid die is cylindrical in shape, with a slot
+through one side which enables one to obtain a slight degree of
+adjustment by squeezing the slotted portion together. Large dies, or the
+sizes over 1/2 inch, are usually made in two pieces in order that the
+halves may be closed up or brought nearer together. The advantage of
+this form of die is that either of the two pieces may be easily
+sharpened, and as it may be adjusted very easily the thread may be cut
+by easy stages. For example, the die may be adjusted to cut large, which
+will produce a shallow thread that will act as an accurate guide when
+the die is closed up and a deeper thread cut.
+
+[Illustration: Fig. 172.--Showing Holder Designs for One- and Two-Piece
+Thread Cutting Dies.]
+
+A common form of die holder for an adjustable die is shown at Fig. 172,
+A. As will be apparent, it consists of a central body portion having
+guide members to keep the die pieces from falling out and levers at each
+end in order to permit the operator to exert sufficient force to remove
+the metal. The method of adjusting the depth of thread with a clamp
+screw when a two-piece die is employed is also clearly outlined. The
+diestock shown at B is used for the smaller dies of the one-piece
+pattern, having a slot in order that they may be closed up slightly by
+the clamp screw. The reverse side of the diestock shown at B is outlined
+below it, and the guide pieces, which may be easily moved in or out,
+according to the size of the piece to be threaded by means of
+eccentrically disposed semi-circular slots in the adjustment plate, are
+shown. These movable guide members have small pins let into their
+surface which engage the slots, and they may be moved in or out, as
+desired, according to the position of the adjusting plate. The use of
+the guide pieces makes for accurate positioning or centering of the rod
+to be threaded. Dies are usually sold in sets, and are commonly
+furnished as a portion of a complete outfit such as outlined at Fig.
+173. That shown has two sizes of diestock, a tap wrench, eight assorted
+dies, eight assorted taps, and a small screw driver for adjusting the
+die. An automobile repair shop should be provided with three different
+sets of taps and dies, as three different standards for the bolts and
+nuts are used in fastening automobile components. These are the
+American, metric (used on foreign engines), and the S. A. E. standard
+threads. A set of pipe dies and taps will also be found useful.
+
+[Illustration: Fig. 173.--Useful Outfit of Taps and Dies for the Engine
+Repair Shop.]
+
+
+MEASURING TOOLS
+
+The tool outfit of the machinist or the mechanic who aspires to do
+machine work must include a number of measuring tools which are not
+needed by the floor man or one who merely assembles and takes apart the
+finished pieces. The machinist who must convert raw material into
+finished products requires a number of measuring tools, some of which
+are used for taking only approximate measurements, such as calipers and
+scales, while others are intended to take very accurate measurements,
+such as the Vernier and the micrometer. A number of common forms of
+calipers are shown at Fig. 174. These are known as inside or outside
+calipers, depending upon the measurements they are intended to take.
+That at A is an inside caliper, consisting of two legs, A and D, and a
+gauging piece, B, which can be locked to leg A, or released from that
+member by the screw, C. The object of this construction is to permit of
+measurements being taken at the bottom of a two diameter hole, where the
+point to be measured is of larger diameter than the portion of the hole
+through which the calipers entered. It will be apparent that the legs A
+and D must be brought close together to pass through the smaller holes.
+This may be done without losing the setting, as the guide bar B will
+remain in one position as determined by the size of the hole to be
+measured, while the leg A may be swung in to clear the obstruction as
+the calipers are lifted out. When it is desired to ascertain the
+measurements the leg A is pushed back into place into the slotted
+portion of the guide B, and locked by the clamp screw C. A tool of this
+form is known as an internal transfer caliper.
+
+[Illustration: Fig. 174.--Common Forms of Inside and Outside Calipers.]
+
+The form of caliper shown at B is an outside caliper. Those at C and D
+are special forms for inside and outside work, the former being used,
+if desired, as a divider, while the latter may be employed for measuring
+the walls of tubing. The calipers at E are simple forms, having a
+friction joint to distinguish them from the spring calipers shown at B,
+C and D. In order to permit of ready adjustment of a spring caliper, a
+split nut as shown at G is sometimes used. A solid nut caliper can only
+be adjusted by screwing the nut in or out on the screw, which may be a
+tedious process if the caliper is to be set from one extreme to the
+other several times in succession. With a slip nut as shown at G it is
+possible to slip it from one end of the thread to the other without
+turning it, and of locking it in place at any desired point by simply
+allowing the caliper leg to come in contact with it. The method of
+adjusting a spring caliper is shown at Fig. 174, H.
+
+Among the most common of the machinist's tools are those used for linear
+measurements. The usual forms are shown in group, Fig. 175. The most
+common tool, which is widely known, is the carpenter's folding two-foot
+rule or the yardstick. While these are very convenient for taking
+measurements where great accuracy is not required, the machinist must
+work much more accurately than the carpenter, and the standard steel
+scale which is shown at D, is a popular tool for the machinist. The
+steel scale is in reality a graduated straight edge and forms an
+important part of various measuring tools. These are made of high grade
+steel and vary from 1 to 48 inches in length. They are carefully
+hardened in order to preserve the graduations, and all surfaces and
+edges are accurately ground to insure absolute parallelism. The
+graduations on the high grade scales are produced with a special device
+known as a dividing engine, but on cheaper scales, etching suffices to
+provide a fairly accurate graduation. The steel scales may be very thin
+and flexible, or may be about an eighth of an inch thick on the
+twelve-inch size, which is that commonly used with combination squares,
+protractors and other tools of that nature. The repairman's scale
+should be graduated both with the English system, in which the inches
+are divided into eighths, sixteenths, thirty-secondths and
+sixty-fourths, and also in the metric system, divided into millimeters
+and centimeters. Some machinists use scales graduated in tenths,
+twentieths, fiftieths and hundredths. This is not as good a system of
+graduation as the more conventional one first described.
+
+[Illustration: Fig. 175.--Measuring Appliances for the Machinist and
+Floor Man.]
+
+Some steel scales are provided with a slot or groove cut the entire
+length on one side and about the center of the scales. This permits the
+attachment of various fittings such as the protractor head, which
+enables the machinist to measure angles, or in addition the heads
+convert the scale into a square or a tool permitting the accurate
+bisecting of pieces of circular section. Two scales are sometimes joined
+together to form a right angle, such as shown at Fig. 175, C. This is
+known as a square and is very valuable in ascertaining the truth of
+vertical pieces that are supposed to form a right angle with a base
+piece.
+
+The Vernier is a device for reading finer divisions on a scale than
+those into which the scale is divided. Sixty-fourths of an inch are
+about the finest division that can be read accurately with the naked
+eye. When fine work is necessary a Vernier is employed. This consists
+essentially of two rules so graduated that the true scale has each inch
+divided into ten equal parts, the upper or Vernier portion has ten
+divisions occupying the same space as nine of the divisions of the true
+scale. It is evident, therefore, that one of the divisions of the
+Vernier is equal to nine-tenths of one of those on the true scale. If
+the Vernier scale is moved to the right so that the graduations marked
+"1" shall coincide, it will have moved one-tenth of a division on the
+scale or one-hundredth of an inch. When the graduations numbered 5
+coincide the Vernier will have moved five-hundredths of an inch; when
+the lines marked 0 and 10 coincide, the Vernier will have moved
+nine-hundredths of an inch, and when 10 on the Vernier comes opposite 10
+on the scales, the upper rule will have moved ten-hundredths of an inch,
+or the whole of one division on the scale. By this means the scale,
+though it may be graduated only to tenths of an inch, may be accurately
+set at points with positions expressed in hundredths of an inch. When
+graduated to read in thousandths, the true scale is divided into fifty
+parts and the Vernier into twenty parts. Each division of the Vernier
+is therefore equal to nineteen-twentieths of one of the true scale. If
+the Vernier be moved so the lines of the first division coincide, it
+will have moved one-twentieth of one-fiftieth, or .001 inch. The Vernier
+principle can be readily grasped by studying the section of the Vernier
+scale and true scale shown at Fig. 176, A.
+
+[Illustration: Fig. 176.--At Left, Special Form of Vernier Caliper for
+Measuring Gear Teeth; at Right, Micrometer for Accurate Internal
+Measurements.]
+
+The caliper scale which is shown at Fig. 175, A, permits of taking the
+over-all dimension of any parts that will go between the jaws. This
+scale can be adjusted very accurately by means of a fine thread screw
+attached to a movable jaw and the divisions may be divided by eye into
+two parts if one sixty-fourth is the smallest of the divisions. A line
+is indicated on the movable jaw and coincides with the graduations on
+the scale. As will be apparent, if the line does not coincide exactly
+with one of the graduations it will be at some point between the lines
+and the true measurement may be approximated without trouble.
+
+A group of various other measuring tools of value to the machinist is
+shown at Fig. 177. The small scale at A is termed a "center gauge,"
+because it can be used to test the truth of the taper of either a male
+or female lathe center. The two smaller nicks, or v's, indicate the
+shape of a standard thread, and may be used as a guide for grinding the
+point of a thread-cutting tool. The cross level which is shown at B is
+of marked utility in erecting, as it will indicate absolutely if the
+piece it is used to test is level. It will indicate if the piece is
+level along its width as well as its length.
+
+[Illustration: Fig. 177.--Measuring Appliances of Value in Airplane
+Repair Work.]
+
+A very simple attachment for use with a scale that enables the machinist
+to scribe lines along the length of a cylindrical piece is shown at Fig.
+177, C. These are merely small wedge-shaped clamps having an angular
+face to rest upon the bars. The thread pitch gauge which is shown at
+Fig. 177, D, is an excellent pocket tool for the mechanic, as it is
+often necessary to determine without loss of time the pitch of the
+thread on a bolt or in a nut. This consists of a number of leaves having
+serrations on one edge corresponding to the standard thread it is to be
+used in measuring. The tool shown gives all pitches up to 48 threads per
+inch. The leaves may be folded in out of the way when not in use, and
+their shape admits of their being used in any position without the
+remainder of the set interfering with the one in use. The fine pitch
+gauges have slim, tapering leaves of the correct shape to be used in
+finding the pitch of small nuts. As the tool is round when the leaves
+are folded back out of the way, it is an excellent pocket tool, as there
+are no sharp corners to wear out the pocket. Practical application of a
+Vernier having measuring heads of special form for measuring gear teeth
+is shown at Fig. 176, A. As the action of this tool has been previously
+explained, it will not be necessary to describe it further.
+
+
+MICROMETER CALIPERS AND THEIR USE
+
+Where great accuracy is necessary in taking measurements the micrometer
+caliper, which in the simple form will measure easily .001 inch
+(one-thousandth part of an inch) and when fitted with a Vernier that
+will measure .0001 inch (one ten-thousandth part of an inch), is used.
+The micrometer may be of the caliper form for measuring outside
+diameters or it may be of the form shown at Fig. 176, B, for measuring
+internal diameters. The operation of both forms is identical except that
+the internal micrometer is placed inside of the bore to be measured
+while the external form is used just the same as a caliper. The form
+outlined will measure from one and one-half to six and a half inches as
+extension points are provided to increase the range of the instrument.
+The screw has a movement of one-half inch and a hardened anvil is placed
+in the end of the thimble in order to prevent undue wear at that point.
+The extension points or rods are accurately made in standard lengths and
+are screwed into the body of the instrument instead of being pushed in,
+this insuring firmness and accuracy. Two forms of micrometers for
+external measurements are shown at Fig. 178. The top one is graduated
+to read in thousandths of an inch, while the lower one is graduated to
+indicate hundredths of a millimeter. The mechanical principle involved
+in the construction of a micrometer is that of a screw free to move in a
+fixed nut. An opening to receive the work to be measured is provided by
+the backward movement of the thimble which turns the screw and the size
+of the opening is indicated by the graduations on the barrel.
+
+[Illustration: Fig. 178.--Standard Forms of Micrometer Caliper for
+External Measurements.]
+
+The article to be measured is placed between the anvil and spindle, the
+frame being held stationary while the thimble is revolved by the thumb
+and finger. The pitch of the screw thread on the concealed part of the
+spindle is 40 to an inch. One complete revolution of the spindle,
+therefore, moves it longitudinally one-fortieth, or twenty-five
+thousandths of an inch. As will be evident from the development of the
+scale on the barrel of the inch micrometer, the sleeve is marked with
+forty lines to the inch, each of these lines indicating twenty-five
+thousandths. The thimble has a beveled edge which is graduated into
+twenty-five parts. When the instrument is closed the graduation on the
+beveled edge of the thimble marked 0 should correspond to the 0 line on
+the barrel. If the micrometer is rotated one full turn the opening
+between the spindle and anvil will be .025 inch. If the thimble is
+turned only one graduation, or one twenty-fifth of a revolution, the
+opening between the spindle and anvil will be increased only by .001
+inch (one-thousandth of an inch).
+
+As many of the dimensions of the airplane parts, especially of those of
+foreign manufacture or such parts as ball and roller bearings, are based
+on the metric system, the competent repairman should possess both inch
+and metric micrometers in order to avoid continual reference to a table
+of metric equivalents. With a metric micrometer there are fifty
+graduations on the barrel, these representing .01 of a millimeter, or
+approximately .004 inch. One full turn of the barrel means an increase
+of half a millimeter, or .50 mm. (fifty one-hundredths). As it takes two
+turns to augment the space between the anvil and the stem by increments
+of one millimeter, it will be evident that it would not be difficult to
+divide the spaces on the metric micrometer thimble in halves by the eye,
+and thus the average workman can measure to .0002 inch plus or minus
+without difficulty. As set in the illustration, the metric micrometers
+show a space of 13.5 mm., or about one millimeter more than half an
+inch. The inch micrometer shown is set to five-tenths or five hundred
+one-thousandths or one-half inch. A little study of the foregoing matter
+will make it easy to understand the action of either the inch or metric
+micrometer.
+
+Both of the micrometers shown have a small knurled knob at the end of
+the barrel. This controls the ratchet stop, which is a device that
+permits a ratchet to slip by a pawl when more than a certain amount of
+pressure is applied, thereby preventing the measuring spindle from
+turning further and perhaps springing the instrument. A simple rule that
+can be easily memorized for reading the inch micrometer is to multiply
+the number of vertical divisions on the sleeve by 25 and add to that the
+number of divisions on the bevel of the thimble reading from the zero to
+the line which coincides with the horizontal line on the sleeve. For
+example: if there are ten divisions visible on the sleeve, multiply this
+number by 25, then add the number of divisions shown on the bevel of the
+thimble, which is 10. The micrometer is therefore opened 10 x 25 equals
+250 plus 10 equals 260 thousandths.
+
+Micrometers are made in many sizes, ranging from those having a maximum
+opening of one inch to special large forms that will measure forty or
+more inches. While it is not to be expected that the repairman will have
+use for the big sizes, if a caliper having a maximum opening of six
+inches is provided with a number of extension rods enabling one to
+measure smaller objects, practically all of the measuring needed in
+repairing engine parts can be made accurately. Two or three smaller
+micrometers having a maximum range of two or three inches will also be
+found valuable, as most of the measurements will be made with these
+tools which will be much easier to handle than the larger sizes.
+
+
+TYPICAL TOOL OUTFITS
+
+The equipment of tools necessary for repairing airplane engines depends
+entirely upon the type of the power plant and while the common hand
+tools can be used on all forms, the work is always facilitated by having
+special tools adapted for reaching the nuts and screws that would be
+hard to reach otherwise. Special spanners and socket wrenches are very
+desirable. Then again, the nature of the work to be performed must be
+taken into consideration. Rebuilding or overhauling an engine calls for
+considerably more tools than are furnished for making field repairs or
+minor adjustments. A complete set of tools supplied to men working on
+Curtiss OX-2 engines and JN-4 training biplanes is shown at Fig. 179.
+The tools are placed in a special box provided with a hinged cover and
+are arranged in the systematic manner outlined. The various tools and
+supplies shown are: A, hacksaw blades; B, special socket wrenches for
+engine bolts and nuts; C, ball pein hammers, four sizes; D, five
+assorted sizes of screw drivers ranging from very long for heavy work to
+short and small for fine work; E, seven pairs of pliers including
+combination in three sizes, two pairs of cutting pliers and one round
+nose; F, two split pin extractors and spreaders; G, wrench set including
+three adjustable monkey wrenches, one Stillson or pipe wrench, five
+sizes adjustable end wrenches and ten double end S wrenches; H, set of
+files, including flat, three cornered and half round; I, file brush; J,
+chisel and drift pin; K, three small punches or drifts; L, hacksaw
+frame; M, soldering copper; N, special spanners for propeller retaining
+nuts; O, special spanners; P, socket wrenches, long handle; Q, long
+handle, stiff bristle brushes for cleaning motor; R, gasoline blow
+torch; S, hand drill; T, spools of safety wire; U, flash lamp; V,
+special puller and castle wrenches; W, oil can; X, large adjustable
+monkey wrench; Y, washer and gasket cutter; Z, ball of heavy twine. In
+addition to the tools, various supplies, such as soldering acid, solder,
+shellac, valve grinding compound, bolts and nuts, split pins, washers,
+wood screws, etc., are provided.
+
+[Illustration: Fig. 179.--Special Tools for Maintaining Curtiss OX-2
+Motor Used in Curtiss JN-4 Training Biplane.]
+
+
+SPECIAL HALL-SCOTT TOOLS
+
+ NO. TOOL DIRECTIONS FOR USE
+ 1 Engine hoisting hook, 6-cylinder Hook under cam-shaft housing,
+ when hoisting engine.
+ 2 Engine hoisting hook, 4-cylinder Hook under cam-shaft housing,
+ when hoisting engine.
+ 3 Water plug wrench For use on water plugs on top
+ and end of cylinders.
+ 4 Vertical shaft flange puller For pulling lower pinion shaft
+ flange from shaft. (Used on A-5
+ and A-7 engines only.)
+ 5 Oil gun For general lubrication use.
+ 6 Magneto gear puller For pulling magneto gears from
+ magneto shaft.
+ 7 Socket wrench, 1/4" A.L.A.M. For use on bolts and nuts on
+ crank cases.
+ 8 Socket wrench, 1/4" A.L.A.M For use on crank cases and
+ magneto gear housings.
+ 9 Socket wrench, 1/4" A.L.A.M. For use on magneto gear
+ housings.
+ 10 Socket wrench, 3/8" standard For bolts and nuts which fasten
+ magnetos to crank-case.
+ 11 Socket wrench, 1/4" A.L.A.M. For use on magneto gear
+ housings.
+ 12 Vertical shaft gear puller For removing water pump and
+ magneto drive gear.
+ 13 Brace and facing cutter For facing lugs on cylinders for
+ cylinder hold down stud washers.
+ 14 Handle for brace Use with brace.
+ 15 Valve grinding brace For grinding in valves.
+ 16 Socket wrench base, 3/8" A.L.A.M. For thrust bearing cap screws.
+ 17 Brace and facing cutter, 5/16" For facing lugs on rocker arm
+ A.L.A.M. covers.
+ 18 Valve grinding screw driver For grinding in valves.
+ 19 Valve spring tool For putting on and taking off
+ valve springs.
+ 20 Block-valve spring tool For use with valve spring tool.
+ 21 Socket wrench, 5/8" A.L.A.M. For main bearing nuts.
+ 22 Socket wrench, 1/4" A.L.A.M. For use on cam-shaft housing.
+ 23 Socket wrench, 5/16" A.L.A.M. For cam-shaft housing hold down
+ stud nuts.
+ 24 Socket wrench, 1/2" A.L.A.M. For cylinder hold down stud
+ nuts.
+ 25 Socket wrench, 5/16" A.L.A.M. For carburetor and water pump
+ bolts and nuts.
+ 26 Socket wrench, 5/16" A.L.A.M. For carburetor and water pump
+ bolts and nuts.
+ 27 Socket wrench For use on carburetor jets.
+ 28 Magneto screw driver For general magneto use.
+ 29 Brass bar, 1" diameter x 7" long For driving piston pins from
+ pistons.
+ 30 Hack saw For general use.
+ 31 Oil can For cam-shaft housing
+ lubrication.
+ 32 Gasoline or distillate can For priming or other use.
+ 33 Oil can For magneto gear lubrication.
+ 34 Shellac can For rubber hose connections and
+ gaskets.
+ 35 Magneto cleaner For use on magnetos.
+ 36 Clamps For holding cylinder hold down
+ studs, when fitting main
+ bearings.
+ 37 Piston guards For use in pistons, when out of
+ engine, to protect them.
+ 38 Screw driver For general use.
+ 39 Vertical shaft clamps For clamping vertical shaft
+ flanges, when timing engine.
+ 40 Thrust adjusting nut wrench For adjusting propeller thrust
+ bearing.
+ 41 Stuffing box spanner wrench For adjusting stuffing box nut
+ on vertical shaft.
+ 42 Water pump spanner wrench For adjusting water pump
+ stuffing nut.
+ 43 Wrench For use on cylinder relief cocks
+ and cylinder priming cocks.
+ 44 Hose clamp wrench For use on hose clamps.
+ 45 Scraper For cleaning piston ring grooves
+ on pistons.
+ 46 Crank-shaft nut wrench For adjusting crank-shaft nut.
+ 47 Spark-plug wrench For putting in and taking out
+ spark-plugs in cylinders.
+ 48 Timing disc (single disc) For use on crank-shaft to time
+ engine.
+ Specify type motor disc should be made for. If double disc is
+ required, specify the two types of motors the disc is to be made
+ for. Double disc.
+ 49 Main bearing scraper For scraping in bearings.
+ 50 Cylinder carbon scraper For removing carbon from heads
+ of cylinders.
+ 51 Valve seating tool For seating valves in cylinder
+ heads.
+ 52 Scraper, small For general bearing use.
+ 53 Scraper, large For general bearing use.
+ 54 Crank-shaft flange puller For pulling crank-shaft flange
+ from crank-shaft.
+ 55 Piston and connecting rod racks.
+ 56 Main bearing stud nuts and shim
+ rack.
+ 57 Main bearing board rack.
+ 58 Rocker arm and cover rack.
+
+The special tools and fixtures recommended by the Hall-Scott Company for
+work on their engines are clearly shown at Fig. 180. All tools are
+numbered and their uses may be clearly understood by reference to the
+illustration and explanatory list given on pages 410 and 411.
+
+
+OVERHAULING AIRPLANE ENGINES
+
+After an airplane engine has been in use for a period ranging from 60 to
+80 hours, depending upon the type, it is necessary to give it a thorough
+overhauling before it is returned to service. To do this properly, the
+engine is removed from the fuselage and placed on a special supporting
+stand, such as shown at Fig. 181, so it can be placed in any position
+and completely dismantled. With a stand of this kind it is as easy to
+work on the bottom of the engine as on the top and every part can be
+instantly reached. The crank-case shown in place in illustration is in a
+very convenient position for scraping in the crank-shaft bearings.
+
+[Illustration: Fig. 180.--Special Tools and Appliances to Facilitate
+Overhauling Work on Hall-Scott Airplane Engines.]
+
+In order to look over the parts of an engine and to restore the worn or
+defective components it is necessary to take the engine entirely apart,
+as it is only when the power plant is thoroughly dismantled that the
+parts can be inspected or measured to determine defects or wear. If one
+is not familiar with the engine to be inspected, even though the work is
+done by a repairman of experience, it will be found of value to take
+certain precautions when dismantling the engine in order to insure that
+all parts will be replaced in the same position they occupied before
+removal. There are a number of ways of identifying the parts, one of the
+simplest and surest being to mark them with steel numbers or letters or
+with a series of center punch marks in order to retain the proper
+relation when reassembling. This is of special importance in connection
+with dismantling multiple cylinder engines as it is vital that pistons,
+piston rings, connecting rods, valves, and other cylinder parts be
+always replaced in the same cylinder from which they were removed,
+because it is uncommon to find equal depreciation in all cylinders. Some
+repairmen use small shipping tags to identify the pieces. This can be
+criticised because the tags may become detached and lost and the
+identity of the piece mistaken. If the repairing is being done in a shop
+where other engines of the same make are being worked on, the repairman
+should be provided with a large chest fitted with a lock and key in
+which all of the smaller parts, such as rods, bolts and nuts, valves,
+gears, valve springs, cam-shafts, etc., may be stored to prevent the
+possibility of confusion with similar members of other engines. All
+parts should be thoroughly cleaned with gasoline or in the potash kettle
+as removed, and wiped clean and dry. This is necessary to show wear
+which will be evidenced by easily identified indications in cases where
+the machine has been used for a time, but in others, the deterioration
+can only be detected by delicate measuring instruments.
+
+[Illustration: Fig. 181.--Special Stand to Make Motor Overhauling Work
+Easier.]
+
+In taking down a motor the smaller parts and fittings such as
+spark-plugs, manifolds and wiring should be removed first. Then the more
+important members such as cylinders may be removed from the crank-case
+to give access to the interior and make possible the examination of the
+pistons, rings and connecting rods. After the cylinders are removed the
+next operation is to disconnect the connecting rods from the crank-shaft
+and to remove them and the pistons attached as a unit. Then the
+crank-case is dismembered, in most cases by removing the bottom half or
+oil sump, thus exposing the main bearings and crank-shaft. The first
+operation is the removal of the inlet and exhaust manifolds. In some
+cases the manifolds are cored integral with the cylinder head casting
+and it is merely necessary to remove a short pipe leading from the
+carburetor to one inlet opening and the exhaust pipe from the outlet
+opening common to all cylinders. In order to remove the carburetor it is
+necessary to shut off the gasoline supply at the tank and to remove the
+pipe coupling at the float chamber. It is also necessary to disconnect
+the throttle operating rod. After the cylinders are removed and before
+taking the crank-case apart it is well to remove the water pump and
+magneto. The wiring on most engines of modern development is carried in
+conduits and usually releasing two or three minor fastenings will permit
+one to take off the plug wiring as a unit. The wire should be
+disconnected from both spark-plugs and magneto distributor before its
+removal. When the cylinders are removed, the pistons, piston rings, and
+connecting rods are clearly exposed and their condition may be readily
+noticed.
+
+Before disturbing the arrangement of the timing gears, it is important
+that these be marked so that they will be replaced in exactly the same
+relation as intended by the engine designer. If the gears are properly
+marked the valve timing and magneto setting will be undisturbed when the
+parts are replaced after overhauling. With the cylinders off, it is
+possible to ascertain if there is any undue wear present in the
+connecting rod bearings at either the wrist pin or crank-pin ends and
+also to form some idea of the amount of carbon deposits on the piston
+top and back of the piston rings. Any wear of the timing gears can also
+be determined. The removal of the bottom plate of the engine enables the
+repairman to see if the main bearings are worn unduly. Often bearings
+may be taken up sufficiently to eliminate all looseness. In other cases
+they may be worn enough so that careful refitting will be necessary.
+Where the crank-case is divided horizontally into two portions, the
+upper one serving as an engine base to which the cylinders and in fact
+all important working parts are attached, the lower portion performs the
+functions of an oil container and cover for the internal mechanism. This
+is the construction generally followed.
+
+
+DEFECTS IN CYLINDERS
+
+After the cylinders have been removed and stripped of all fittings, they
+should be thoroughly cleaned and then carefully examined for defects.
+The interior or bore should be looked at with a view of finding score
+marks, grooves, cuts or scratches in the interior, because there are
+many faults that may be ascribed to depreciation at this point. The
+cylinder bore may be worn out of round, which can only be determined by
+measuring with an internal caliper or dial indicator even if the
+cylinder bore shows no sign of wear. The flange at the bottom of the
+cylinder by which it is held to the engine base may be cracked. The
+water jacket wall may have opened up due to freezing of the jacket
+water at some time or other or it may be filled with scale and sediment
+due to the use of impure cooling water. The valve seat may be scored or
+pitted, while the threads holding the valve chamber cap may be worn so
+that the cap will not be a tight fit. The detachable head construction
+makes it possible to remove that member and obtain ready access to the
+piston tops for scraping out carbon without taking the main cylinder
+portion from the crank-case. When the valves need grinding the head may
+be removed and carried to the bench where the work may be performed with
+absolute assurance that none of the valve grinding compound will
+penetrate into the interior of the cylinder as is sometimes unavoidable
+with the I-head cylinder. If the cylinder should be scored, the water
+jacket and combustion head may be saved and a new cylinder casting
+purchased at considerably less cost than that of the complete unit
+cylinder.
+
+The detachable head construction has only recently been applied on
+airplane engines, though it was one of the earliest forms of automobile
+engine construction. In the early days it was difficult to procure
+gaskets or packings that would be both gas and water tight. The sheet
+asbestos commonly used was too soft and blew out readily. Besides a new
+gasket had to be made every time the cylinder head was removed. Woven
+wire and asbestos packings impregnated with rubber, red lead, graphite
+and other filling materials were more satisfactory than the soft sheet
+asbestos, but were prone to burn out if the water supply became low.
+Materials such as sheet copper or brass proved to be too hard to form a
+sufficiently yielding packing medium that would allow for the inevitable
+slight inaccuracies in machining the cylinder head and cylinder. The
+invention of the copper-asbestos gasket, which is composed of two sheets
+of very thin, soft copper bound together by a thin edging of the same
+material and having a piece of sheet asbestos interposed solved this
+problem. Copper-asbestos packings form an effective seal against leakage
+of water and a positive retention means for keeping the explosion
+pressure in the cylinder. The great advantage of the detachable head is
+that it permits of very easy inspection of the piston tops and
+combustion chamber and ready removal of carbon deposits.
+
+
+CARBON DEPOSITS, THEIR CAUSE AND PREVENTION
+
+Most authorities agree that carbon is the result of imperfect combustion
+of the fuel and air mixture as well as the use of lubricating oils of
+improper flash point. Lubricating oils that work by the piston rings may
+become decomposed by the great heat in the combustion chamber, but at
+the same time one cannot blame the lubricating oil for all of the carbon
+deposits. There is little reason to suspect that pure petroleum oil of
+proper body will deposit excessive amounts of carbon, though if the oil
+is mixed with castor oil, which is of vegetable origin, there would be
+much carbon left in the interior of the combustion chamber. Fuel
+mixtures that are too rich in gasoline also produce these undesirable
+accumulations.
+
+A very interesting chemical analysis of a sample of carbon scraped from
+the interior of a motor vehicle engine shows that ordinarily the
+lubricant is not as much to blame as is commonly supposed. The analysis
+was as follows:
+
+ Oil 14.3%
+ Other combustible matter 17.9
+ Sand, clay, etc. 24.8
+ Iron oxide 24.5
+ Carbonate of lime 8.9
+ Other constituents 9.6
+
+It is extremely probable that the above could be divided into two
+general classes, these being approximately 32.2% oil and combustible
+matter and a much larger proportion, or 67.8% of earthy matter. The
+presence of such a large percentage of earthy matter is undoubtedly due
+to the impurities in the air, such as road dust which has been sucked
+in through the carburetor. The fact that over 17% of the matter which is
+combustible was not of an oily nature lends strong support to this view.
+There would not be the amount of earthy material present in the carbon
+deposits of an airplane engine as above stated because the air is almost
+free from dust at the high altitudes planes are usually flown. One could
+expect to find more combustible and less earthy matter and the carbon
+would be softer and more easily removed. It is very good practice to
+provide a screen on the air intake to reduce the amounts of dust sucked
+in with the air as well as observing the proper precautions relative to
+supplying the proper quantities of air to the mixture and of not using
+any more oil than is needed to insure proper lubrication of the internal
+mechanism.
+
+
+USE OF CARBON SCRAPERS
+
+It is not unusual for one to hear an aviator complain that the engine he
+operates is not as responsive as it was when new after he has run it but
+relatively few hours. There does not seem to be anything actually wrong
+with the engine, yet it does not respond readily to the throttle and is
+apt to overheat. While these symptoms denote a rundown condition of the
+mechanism, the trouble is often due to nothing more serious than
+accumulations of carbon. The remedy is the removal of this matter out of
+place. The surest way of cleaning the inside of the motor thoroughly is
+to remove the cylinders, if these members are cast integrally with the
+head or of removing the head member if that is a separate casting, to
+expose all parts.
+
+In certain forms of cylinders, especially those of the L form, it is
+possible to introduce simple scrapers down through the valve chamber cap
+holes and through the spark-plug hole if this component is placed in the
+cylinder in some position that communicates directly to the interior of
+the cylinder or to the piston top. No claim can be made for originality
+or novelty of this process as is has been used for many years on large
+stationary engines. The first step is to dismantle the inlet and exhaust
+piping and remove the valve caps and valves, although if the deposit is
+not extremely hard or present in large quantities one can often
+manipulate the scrapers in the valve cap openings without removing
+either the piping or the valves. Commencing with the first cylinder, the
+crank-shaft is turned till the piston is at the top of its stroke, then
+the scraper may be inserted, and the operation of removing the carbon
+started by drawing the tool toward the opening. As this is similar to a
+small hoe, the cutting edge will loosen some of the carbon and will draw
+it toward the opening. A swab is made of a piece of cloth or waste
+fastened at the end of a wire and well soaked in kerosene to clean out
+the cylinder.
+
+When available, an electric motor with a length of flexible shaft and a
+small circular cleaning brush having wire bristles can be used in the
+interior of the engine. The electric motor need not be over one-eighth
+horse-power running 1,200 to 1,600 R. P. M., and the wire brush must, of
+course, be of such size that it can be easily inserted through the valve
+chamber cap. The flexible shaft permits one to reach nearly all parts of
+the cylinder interior without difficulty and the spreading out and
+flattening of the brush insures that considerable surface will be
+covered by that member.
+
+
+BURNING OUT CARBON WITH OXYGEN
+
+A process of recent development that gives very good results in removing
+carbon without disassembling the motor depends on the process of burning
+out that material by supplying oxygen to support the combustion and to
+make it energetic. A number of concerns are already offering apparatus
+to accomplish this work, and in fact any shop using an autogenous
+welding outfit may use the oxygen tank and reducing valve in connection
+with a simple special torch for burning the carbon. Results have
+demonstrated that there is little danger of damaging the motor parts,
+and that the cost of oxygen and labor is much lower than the old method
+of removing the cylinders and scraping the carbon out, as well as being
+very much quicker than the alternative process of using carbon solvent.
+The only drawback to this system is that there is no absolute insurance
+that every particle of carbon will be removed, as small protruding
+particles may be left at points that the flame does not reach and cause
+pre-ignition and consequent pounding, even after the oxygen treatment.
+It is generally known that carbon will burn in the presence of oxygen,
+which supports combustion of all materials, and this process takes
+advantage of this fact and causes the gas to be injected into the
+combustion chamber over a flame obtained by a match or wax taper.
+
+[Illustration: Fig. 182.--Showing Where Carbon Deposits Collect in
+Engine Combustion Chamber, and How to Burn Them Out with the Aid of
+Oxygen. A--Special Torch. B--Torch Coupled to Oxygen Tank. C--Torch in
+Use.]
+
+It is suggested by those favoring this process that the night before the
+oxygen is to be used the engine be given a conventional kerosene
+treatment. A half tumbler full of this liquid or of denatured alcohol is
+to be poured into each cylinder and permitted to remain there over
+night. As a precaution against fire, the gasoline is shut off from the
+carburetor before the torch is inserted in the cylinder and the motor
+started so that the gasoline in the pipe and carburetor float chamber
+will be consumed. Work is done on one cylinder at a time. A note of
+caution was recently sounded by a prominent spark-plug manufacturer
+recommending that the igniter member be removed from the cylinder in
+order not to injure it by the heat developed. The outfits on the market
+consist of a special torch having a trigger controlled valve and a
+length of flexible tubing such as shown at Fig. 182, A, and a regulating
+valve and oxygen tank as shown at B. The gauge should be made to
+register about twelve pounds pressure.
+
+The method of operation is very simple and is outlined at C. The burner
+tube is placed in the cylinder and the trigger valve is opened and the
+oxygen permitted to circulate in the combustion chamber. A lighted match
+or wax taper is dropped in the chamber and the injector tube is moved
+around as much as possible so as to cover a large area. The carbon takes
+fire and burns briskly in the presence of the oxygen. The combustion of
+the carbon is accompanied by sparks and sometimes by flame if the
+deposit is of an oily nature. Once the carbon begins to burn the
+combustion continues without interruption as long as the oxygen flows
+into the cylinder. Full instructions accompany each outfit and the
+amount of pressure for which the regulator should be set depends upon
+the design of the torch and the amount of oxygen contained in the
+storage tank.
+
+
+REPAIRING SCORED CYLINDERS
+
+If the engine has been run at any time without adequate lubrication, one
+or more of the cylinders may be found to have vertical scratches running
+up and down the cylinder walls. The depth of these will vary according
+to the amount of time the cylinder was without lubrication, and if the
+grooves are very deep the only remedy is to purchase a new member. Of
+course, if sufficient stock is available in the cylinder walls, the
+cylinders may be rebored and new pistons which are oversize, _i.e._,
+larger than standard, may be fitted. Where the scratches are not deep
+they may be ground out with a high speed emery wheel or lapped out if
+that type of machine is not available. Wrist pins have been known to
+come loose, especially when these are retained by set screws that are
+not properly locked, and as wrist-pins are usually of hardened steel it
+will be evident that the sharp edge of that member can act as a cutting
+tool and make a pronounced groove in the cylinder. Cylinder grinding is
+a job that requires skilled mechanics, but may be accomplished on any
+lathe fitted with an internal grinding attachment. While automobile
+engine cylinders usually have sufficient wall thickness to stand
+reboring, those of airplane engines seldom have sufficient metal to
+permit of enlarging the bore very much by a boring tool. A few
+thousandths of an inch may be ground out without danger, however. An
+airplane engine cylinder with deep grooves must be scrapped as a general
+rule.
+
+Where the grooves in the cylinder are not deep or where it has warped
+enough so the rings do not bear equally at all parts of the cylinder
+bore, it is possible to obtain a fairly accurate degree of finish by a
+lapping process in which an old piston is coated with a mixture of fine
+emery and oil and is reciprocated up and down in the cylinder as well as
+turned at the same time. This may be easily done by using a dummy
+connecting rod having only a wrist pin end boss, and of such size at the
+other end so that it can be held in the chuck of a drill press. The
+cylinder casting is firmly clamped on the drill press table by suitable
+clamping blocks, and a wooden block is placed in the combustion chamber
+to provide a stop for the piston at its lower extreme position. The back
+gears are put in and the drill chuck is revolved slowly. All the while
+that the piston is turning the drill chuck should be raised up and down
+by the hand feed lever, as the best results are obtained when the
+lapping member is given a combination of rotary and reciprocating
+motion.
+
+
+VALVE REMOVAL AND INSPECTION
+
+One of the most important parts of the gasoline engine and one that
+requires frequent inspection and refitting to keep in condition, is the
+mushroom or poppet valve that controls the inlet and exhaust gas flow.
+In overhauling it is essential that these valves be removed from their
+seatings and examined carefully for various defects which will be
+enumerated at proper time. The problem that concerns us now is the best
+method of removing the valve. These are held against the seating in the
+cylinder by a coil spring which exerts its pressure on the cylinder
+casting at the upper end and against a suitable collar held by a key at
+the lower end of the valve stem. In order to remove the valve it is
+necessary to first compress the spring by raising the collar and pulling
+the retaining key out of the valve stem. Many forms of valve spring
+lifters have been designed to permit ready removal of the valves.
+
+When the cylinder is of the valve in-the-head form, the method of valve
+removal will depend entirely upon the system of cylinder construction
+followed. In the Sturtevant cylinder design it is possible to remove the
+head from the cylinder castings and the valve springs may be easily
+compressed by any suitable means when the cylinder head is placed on the
+work bench where it can be easily worked on. The usual method is to
+place the head on a soft cloth with the valves bearing against the
+bench. The valve springs may then be easily pushed down with a simple
+forked lever and the valve stem key removed to release the valve spring
+collar. In the Curtiss OX-2 (see Fig. 182-1/2) and Hall-Scott engines it
+is not possible to remove the valves without taking the cylinder off
+the crank-case, because the valve seats are machined directly in the
+cylinder head and the valve domes are cast integrally with the cylinder.
+This means that if the valves need grinding the cylinder must be removed
+from the engine base to provide access to the valve heads which are
+inside of that member, and which cannot be reached from the outside as
+is true of the L-cylinder construction. In the Curtiss VX engines, the
+valves are carried in detachable cages which may be removed when the
+valves need attention.
+
+[Illustration: Fig. 182-1/2.--Part Sectional View, Showing Valve
+Arrangement in Cylinder of Curtiss OX-2 Aviation Engine.]
+
+
+RESEATING AND TRUING VALVES
+
+Much has been said relative to valve grinding, and despite the mass of
+information given in the trade prints it is rather amusing to watch the
+average repairman or the engine user who prides himself on maintaining
+his own motor performing this essential operation. The common mistakes
+are attempting to seat a badly grooved or pitted valve head on an
+equally bad seat, which is an almost hopeless job, and of using coarse
+emery and bearing down with all one's weight on the grinding tool with
+the hope of quickly wearing away the rough surfaces. The use of improper
+abrasive material is a fertile cause of failure to obtain a satisfactory
+seating. Valve grinding is not a difficult operation if certain
+precautions are taken before undertaking the work. The most important of
+these is to ascertain if the valve head or seat is badly scored or
+pitted. If such is found to be the case no ordinary amount of grinding
+will serve to restore the surfaces. In this event the best thing to do
+is to remove the valve from its seating and to smooth down both the
+valve head and the seat in the cylinder before attempt is made to fit
+them together by grinding. Another important precaution is to make sure
+that the valve stem is straight, and that the head is not warped out of
+shape.
+
+[Illustration: Fig. 183.--Tools for Restoring Valve Head and Seats.]
+
+A number of simple tools is available at the present time for reseating
+valves, these being outlined at Fig. 183. That shown at A is a simple
+fixture for facing off the valve head. The stem is supported by suitable
+bearings carried by the body or shank of the tool, and the head is
+turned against an angularly disposed cutter which is set for the proper
+valve seat angle. The valve head is turned by a screw-driver, the amount
+of stock removed from the head depending upon the location of the
+adjusting screw. Care must be taken not to remove too much metal, only
+enough being taken off to remove the most of the roughness. Valves are
+made in two standard tapers, the angle being either 45 or 60 degrees. It
+is imperative that the cutter blade be set correctly in order that the
+bevel is not changed. A set of valve truing and valve-seat reaming
+cutters is shown at Fig. 183, B. This is adaptable to various size valve
+heads, as the cutter blade D may be moved to correspond to the size of
+the valve head being trued up. These cutter blades are made of tool
+steel and have a bevel at each end, one at 45 degrees, the other at 60
+degrees. The valve seat reamer shown at G will take any one of the heads
+shown at F. It will also take any one of the guide bars shown at H. The
+function of the guide bars is to fit the valve stem bearing in order to
+locate the reamer accurately and to insure that the valve seat is
+machined concentrically with its normal center. Another form of valve
+seat reamer and a special wrench used to turn it is shown at C. The
+valve head truer shown at Fig. 183, D, is intended to be placed in a
+vise and is adaptable to a variety of valve head sizes. The smaller
+valves merely fit deeper in the conical depression. The cutter blade is
+adjustable and the valve stem is supported by a simple self-centering
+bearing. In operation it is intended that the valve stem, which
+protrudes through the lower portion of the guide bearing, shall be
+turned by a drill press or bit stock while the valve head is set against
+the cutter by pressure of a pad carried at the end of a feed screw which
+is supported by a hinged bridge member. This can be swung out of place
+as indicated to permit placing the valve head against the cutter or
+removing it.
+
+As the sizes of valve heads and stems vary considerably a "Universal"
+valve head truing tool must have some simple means of centering the
+valve stem in order to insure concentric machining of the valve head. A
+valve head truer which employs an ingenious method of guiding the valve
+stem is shown at Fig. 183, E. The device consists of a body portion, B,
+provided with an external thread at the top on which the cutter head, A,
+is screwed. A number of steel balls, C, are carried in the grooves which
+may be altered in size by the adjustment nut, F, which screws in the
+bottom of the body portion, B. As the nut F is screwed in against the
+spacer member E, the V-grooves are reduced in size and the steel balls,
+C, are pressed out in contact with the valve stem. As the circle or
+annulus is filled with balls in both upper and lower portions the stem
+may be readily turned because it is virtually supported by ball bearing
+guides. When a larger valve stem is to be supported, the adjusting nut
+F, is screwed out which increases the size of the grooves and permits
+the balls, C, to spread out and allow the larger stem to be inserted.
+
+
+VALVE GRINDING PROCESSES
+
+Mention has been previously made of the importance of truing both valve
+head and seat before attempt is made to refit the parts by grinding.
+After smoothing the valve seat the next step is to find some way of
+turning the valve. Valve heads are usually provided with a screw-driver
+slot passing through the boss at the top of the valve or with two
+drilled holes to take a forked grinding tool. A combination grinding
+tool has been devised which may be used when either the two drilled
+holes or the slotted head form of valve is to be rotated. This consists
+of a special form of screw driver having an enlarged boss just above the
+blade, this boss serving to support a U-shape piece which can be
+securely held in operative position by the clamp screw or which can be
+turned out of the way if the screw driver blade is to be used.
+
+As it is desirable to turn the valve through a portion of a revolution
+and back again rather than turning it always in the same direction, a
+number of special tools has been designed to make this oscillating
+motion possible without trouble. A simple valve grinding tool is shown
+at Fig. 184, C. This consists of a screw-driver blade mounted in a
+handle in such a way that the end may turn freely in the handle. A
+pinion is securely fastened to the screw-driver blade shank, and is
+adapted to fit a race provided with a wood handle and guided by a bent
+bearing member securely fastened to the screw-driver handle. As the rack
+is pushed back and forth the pinion must be turned first in one
+direction and then in the other.
+
+[Illustration: Fig. 184.--Tools and Processes Utilized in Valve
+Grinding.]
+
+A valve grinding tool patterned largely after a breast drill is shown at
+Fig. 184, D. This is worked in such a manner that a continuous rotation
+of the operating crank will result in an oscillating movement of the
+chuck carrying the screw-driver blade. The bevel pinions which are used
+to turn the chuck are normally free unless clutched to the chuck stem by
+the sliding sleeve which must turn with the chuck stem and which carries
+clutching members at each end to engage similar members on the bevel
+pinions and lock these to the chuck stem, one at a time. The bevel gear
+carries a cam-piece which moves the clutch sleeve back and forth as it
+revolves. This means that the pinion giving forward motion of the chuck
+is clutched to the chuck spindle for a portion of a revolution of the
+gear and clutch sleeve is moved back by the cam and clutched to the
+pinion giving a reverse motion of the chuck during the remainder of the
+main drive gear revolution.
+
+It sometimes happens that the adjusting screw on the valve lift plunger
+or the valve lift plunger itself when L head cylinders are used does not
+permit the valve head to rest against the seat. It will be apparent that
+unless a definite space exists between the end of the valve stem and the
+valve lift plunger that grinding will be of little avail because the
+valve head will not bear properly against the abrasive material smeared
+on the valve seat.
+
+The usual methods of valve grinding are clearly outlined at Fig. 184.
+The view at the left shows the method of turning the valve by an
+ordinary screw driver and also shows a valve head at A, having both the
+drilled holes and the screw-driver slot for turning the member and two
+special forms of fork-end valve grinding tools. In the sectional view
+shown at the right, the use of the light spring between the valve head
+and the bottom of the valve chamber to lift the valve head from the seat
+whenever pressure on the grinding tool is released is clearly indicated.
+It will be noted also that a ball of waste or cloth is interposed in the
+passage between the valve chamber and the cylinder interior to prevent
+the abrasive material from passing into the cylinder from the valve
+chamber. When a bitstock is used, instead of being given a true rotary
+motion the chuck is merely oscillated through the greater part of the
+circle and back again. It is necessary to lift the valve from its seat
+frequently as the grinding operation continues; this is to provide an
+even distribution of the abrasive material placed between the valve head
+and its seat. Only sufficient pressure is given to the bitstock to
+overcome the uplift of the spring and to insure that the valve will be
+held against the seat. Where the spring is not used it is possible to
+raise the valve from time to time with the hand which is placed under
+the valve stem to raise it as the grinding is carried on. It is not
+always possible to lift the valve in this manner when the cylinders are
+in place on the engine base owing to the space between the valve lift
+plunger and the end of the valve stem. In this event the use of the
+spring as shown in sectional view will be desirable.
+
+The abrasive generally used is a paste made of medium or fine emery and
+lard oil or kerosene. This is used until the surfaces are comparatively
+smooth, after which the final polish or finish is given with a paste of
+flour emery, grindstone dust, crocus, or ground glass and oil. An
+erroneous impression prevails in some quarters that the valve head
+surface and the seating must have a mirror-like polish. While this is
+not necessary it is essential that the seat in the cylinder and the
+bevel surface of the head be smooth and free from pits or scratches at
+the completion of the operation. All traces of the emery and oil should
+be thoroughly washed out of the valve chamber with gasoline before the
+valve mechanism is assembled and in fact it is advisable to remove the
+old grinding compound at regular intervals, wash the seat thoroughly and
+supply fresh material as the process is in progress.
+
+The truth of seatings may be tested by taking some Prussian blue pigment
+and spreading a thin film of it over the valve seat. The valve is
+dropped in place and is given about one-eighth turn with a little
+pressure on the tool. If the seating is good both valve head and seat
+will be covered uniformly with color. If high spots exist, the heavy
+deposit of color will show these while the low spots will be made
+evident because of the lack of pigment. The grinding process should be
+continued until the test shows an even bearing of the valve head at all
+points of the cylinder seating. When the valves are held in cages it is
+possible to catch the cage in a vise and to turn the valve in any of the
+ways indicated. It is much easier to clean off the emery and oil and
+there is absolutely no danger of getting the abrasive material in the
+cylinder if the construction is such that the valve cage or cylinder
+head member carrying the valve can be removed from the cylinder. When
+valves are held in cages, the tightness of the seat may be tested by
+partially filling the cage with gasoline and noticing how much liquid
+oozes out around the valve head. The degree of moisture present
+indicates the efficacy of the grinding process.
+
+The valves of Curtiss OX-2 cylinders are easily ground in by using a
+simple fixture or tool and working from the top of the cylinder instead
+of from the inside. A tube having a bore just large enough to go over
+the valve stem is provided with a wooden handle or taped at one end and
+a hole of the same size as that drilled through the valve stem is put in
+at the other. To use, the open end of the tube is pushed over the valve
+stem and a split pin pushed through the tube and stem. The valve may be
+easily manipulated and ground in place by oscillating in the customary
+manner.
+
+
+DEPRECIATION IN VALVE OPERATING SYSTEMS
+
+There are a number of points to be watched in the valve operating system
+because valve timing may be seriously interfered with if there is much
+lost motion at the various bearing points in the valve lift mechanism.
+The two conventional methods of opening valves are shown at Fig. 185.
+That at A is the type employed when the valve cages are mounted directly
+in the head, while the form at B is the system used when the valves are
+located in a pocket or extension of the cylinder casting as is the case
+if an L, or T-head cylinder is used. It will be evident that there are
+several points where depreciation may take place. The simplest form is
+that shown at B, and even on this there are five points where lost
+motion may be noted. The periphery of the valve opening cam or roller
+may be worn, though this is not likely unless the roller or cam has
+been inadvertently left soft. The pin which acts as a bearing for the
+roller may become worn, this occurring quite often. Looseness may
+materialize between the bearing surfaces of the valve lift plunger and
+the plunger guide casting, and there may also be excessive clearance
+between the top of the plunger and the valve stem.
+
+[Illustration: Fig. 185.--Outlining Points in Valve Operating Mechanism
+Where Depreciation is Apt to Exist.]
+
+On the form shown at A, there are several parts added to those indicated
+at B. A walking beam or rocker lever is necessary to transform the
+upward motion of the tappet rod to a downward motion of the valve stem.
+The pin on which this member fulcrums may wear as will also the other
+pin acting as a hinge or bearing for the yoke end of the tappet rod. It
+will be apparent that if slight play existed at each of the points
+mentioned it might result in a serious diminution of valve opening.
+Suppose, for example, that there were .005-inch lost motion at each of
+three bearing points, the total lost motion would be .015-inch or
+sufficient to produce noisy action of the valve mechanism. When valve
+plungers of the adjustable form, such as shown at B, are used, the
+hardened bolt head in contact with the end of the valve stem may become
+hollowed out on account of the hammering action at that point. It is
+imperative that the top of this member be ground off true and the
+clearance between the valve stem and plunger properly adjusted. If the
+plunger is a non-adjustable type it will be necessary to lengthen the
+valve stem by some means in order to reduce the excessive clearance. The
+only remedy for wear at the various hinges and bearing pins is to bore
+the holes out slightly larger and to fit new hardened steel pins of
+larger diameter. Depreciation between the valve plunger guide and the
+valve plunger is usually remedied by fitting new plunger guides in place
+of the worn ones. If there is sufficient stock in the plunger guide
+casting as is sometimes the case when these members are not separable
+from the cylinder casting, the guide may be bored out and bushed with a
+light bronze bushing.
+
+A common cause of irregular engine operation is due to a sticking valve.
+This may be owing to a bent valve stem, a weak or broken valve spring or
+an accumulation of burnt or gummed oil between the valve stem and the
+valve stem guide. In order to prevent this the valve stem must be
+smoothed with fine emery cloth and no burrs or shoulders allowed to
+remain on it, and the stem must also be straight and at right angles to
+the valve head. If the spring is weak it may be strengthened in some
+cases by stretching it out after annealing so that a larger space will
+exist between the coils and re-hardening. Obviously if a spring is
+broken the only remedy is replacement of the defective member.
+
+Mention has been made of wear in the valve stem guide and its influence
+on engine action. When these members are an integral part of the
+cylinder the only method of compensating for this wear is to drill the
+guide out and fit a bushing, which may be made of steel tube.
+
+In some engines, especially those of recent development, the valve stem
+guide is driven or screwed into the cylinder casting and is a separate
+member which may be removed when worn and replaced with a new one. When
+the guides become enlarged to such a point that considerable play exists
+between them and the valve stems, they may be easily knocked out or
+unscrewed.
+
+
+PISTON TROUBLES
+
+If an engine has been entirely dismantled it is very easy to examine the
+pistons for deterioration. While it is important that the piston be a
+good fit in the cylinder it is mainly upon the piston rings that
+compression depends. The piston should fit the cylinder with but little
+looseness, the usual practice being to have the piston about .001-inch
+smaller than the bore for each inch of piston diameter at the point
+where the least heat is present or at the bottom of the piston. It is
+necessary to allow more than this at the top of the piston owing to its
+expansion due to the direct heat of the explosion. The clearance is
+usually graduated and a piston that would be .005-inch smaller than the
+cylinder bore at the bottom would be about .0065-inch at the middle and
+.0075-inch at the top. If much more play than this is evidenced the
+piston will "slap" in the cylinder and the piston will be worn at the
+ends more than in the center. Aluminum or alloy pistons require more
+clearance than cast iron ones do, usually 1.50 times as much. Pistons
+sometimes warp out of shape and are not truly cylindrical. This results
+in the high spots rubbing on the cylinder while the low spots will be
+blackened where a certain amount of gas has leaked by.
+
+Mention has been previously made of the necessity of reboring or
+regrinding a cylinder that has become scored or scratched and which
+allows the gas to leak by the piston rings. When the cylinder is ground
+out, it is necessary to use a larger piston to conform to the enlarged
+cylinder bore. Most manufacturers are prepared to furnish over-size
+pistons, there being four standard over-size dimensions adopted by the
+S. A. E. for rebored cylinders. These are .010-inch, .020-inch,
+.030-inch, and .040-inch larger than the original bore.
+
+The piston rings should be taken out of the piston grooves and all
+carbon deposits removed from the inside of the ring and the bottom of
+the groove. It is important to take this deposit out because it prevents
+the rings from performing their proper functions by reducing the ring
+elasticity, and if the deposit is allowed to accumulate it may
+eventually result in sticking and binding of the ring, this producing
+excessive friction or loss of compression. When the rings are removed
+they should be tested to see if they retain their elasticity and it is
+also well to see that the small pins in some pistons which keep the
+rings from turning around so the joints will not come in line are still
+in place. If no pins are found there is no cause for alarm because these
+dowels are not always used. When fitted, they are utilized with rings
+having a butt joint or diagonal cut as the superior gas retaining
+qualities of the lap or step joint render the pins unnecessary.
+
+If gas has been blowing by the ring or if these members have not been
+fitting the cylinder properly the points where the gas passed will be
+evidenced by burnt, brown or roughened portions of the polished surface
+of the pistons and rings. The point where this discoloration will be
+noticed more often is at the thin end of an eccentric ring, the
+discoloration being present for about 1/2-inch or 3/4-inch each side of
+the slot. It may be possible that the rings were not true when first
+put in. This made it possible for the gas to leak by in small amounts
+initially which increased due to continued pressure until quite a large
+area for gas escape had been created.
+
+
+PISTON RING MANIPULATION
+
+Removing piston rings without breaking them is a difficult operation if
+the proper means are not taken, but is a comparatively simple one when
+the trick is known. The tools required are very simple, being three
+strips of thin steel about one-quarter inch wide and four or five inches
+long and a pair of spreading tongs made up of one-quarter inch diameter
+keystock tied in the center with a copper wire to form a hinge. The
+construction is such that when the hand is closed and the handles
+brought together the other end of the expander spreads out, an action
+just opposite to that of the conventional pliers. The method of using
+the tongs and the metal strips is clearly indicated at Fig. 186. At A
+the ring expander is shown spreading the ends of the rings sufficiently
+to insert the pieces of sheet metal between one of the rings and the
+piston. Grasp the ring as shown at B, pressing with the thumbs on the
+top of the piston and the ring will slide off easily, the thin metal
+strips acting as guide members to prevent the ring from catching in the
+other piston grooves. Usually no difficulty is experienced in removing
+the top or bottom rings, as these members may be easily expanded and
+worked off directly without the use of a metal strip. When removing the
+intermediate rings, however, the metal strips will be found very useful.
+These are usually made by the repairman by grinding the teeth from old
+hacksaw blades and rounding the edges and corners in order to reduce the
+liability of cutting the fingers. By the use of the three metal strips a
+ring is removed without breaking or distorting it and practically no
+time is consumed in the operation.
+
+
+FITTING PISTON RINGS
+
+Before installing new rings, they should be carefully fitted to the
+grooves to which they are applied. The tools required are a large piece
+of fine emery cloth, a thin, flat file, a small vise with copper or
+leaden jaw clips, and a smooth hard surface such as that afforded by the
+top of a surface plate or a well planed piece of hard wood. After making
+sure that all deposits of burnt oil and carbon have been removed from
+the piston grooves, three rings are selected, one for each groove. The
+ring is turned all around its circumference into the groove it is to
+fit, which can be done without springing it over the piston as the
+outside edge of the ring may be used to test the width of the groove
+just as well as the inside edge. The ring should be a fair fit and while
+free to move circumferentially there should be no appreciable up and
+down motion. If the ring is a tight fit it should be laid edge down upon
+the piece of emery cloth which is placed on the surface plate and
+carefully rubbed down until it fits the groove it is to occupy. It is
+advisable to fit each piston ring individually and to mark them in some
+way to insure that they will be placed in the groove to which they are
+fitted.
+
+The repairman next turns his attention to fitting the ring in the
+cylinder itself. The ring should be pushed into the cylinder at least
+two inches up from the bottom and endeavor should be made to have the
+lower edge of the ring parallel with the bottom of the cylinder. If the
+ring is not of correct diameter, but is slightly larger than the
+cylinder bore, this condition will be evident by the angular slots of
+the rings being out of line or by difficulty in inserting the ring if it
+is a lap joint form. If such is the case the ring is removed from the
+cylinder and placed in the vise between soft metal jaw clips. Sufficient
+metal is removed with a fine file from the edges of the ring at the slot
+until the edges come into line and a slight space exists between them
+when the ring is placed into the cylinder. It is important that this
+space be left between the ends, for if this is not done when the ring
+becomes heated the expansion of metal may cause the ends to abut and the
+ring to jam in the cylinder.
+
+[Illustration: Fig. 186.--Method of Removing Piston Rings, and Simple
+Clamp to Facilitate Insertion of Rings in Cylinder.]
+
+It is necessary to use more than ordinary caution in replacing the rings
+on the piston because they are usually made of cast iron, a metal that
+is very fragile and liable to break because of its brittleness. Special
+care should be taken in replacing new rings as these members are more
+apt to break than old ones. This is probably accounted for by the
+heating action on used rings which tends to anneal the metal as well as
+making it less springy. The bottom ring should be placed in position
+first which is easily accomplished by springing the ring open enough to
+pass on the piston and then sliding it into place in the lower groove
+which on some types of engines is below the wrist pin, whereas in others
+all grooves are above that member. The other members are put in by a
+reversal of the process outlined at Fig. 186, A and B. It is not always
+necessary to use the guiding strips of metal when replacing rings as it
+is often possible, by putting the rings on the piston a little askew and
+maneuvering them to pass the grooves without springing the ring into
+them. The top ring should be the last one placed in position.
+
+Before placing pistons in the cylinder one should make sure that the
+slots in the piston rings are spaced equidistant on the piston, and if
+pins are used to keep the ring from turning one should be careful to
+make sure that these pins fit into their holes in the ring and that they
+are not under the ring at any point. Practically all cylinders are
+chamfered at the lower end to make insertion of piston rings easier. The
+operation of putting on a cylinder casting over a piston really requires
+two pairs of hands, one to manipulate the cylinder, the other person to
+close the rings as they enter the cylinder. This may be done very easily
+by a simple clamp member made of sheet brass or iron and used to close
+the ring as indicated at Fig. 186, C. It is apparent that the clamp must
+be adjusted to each individual ring and that the split portion of the
+clamp must coincide with the split portion of the ring. The cylinder
+should be well oiled before any attempt is made to install the pistons.
+The engine should be run with more than the ordinary amount of lubricant
+for several hours after new piston rings have been inserted. On first
+starting the engine, one may be disappointed in that the compression is
+even less than that obtained with the old rings. This condition will
+soon be remedied as the rings become polished and adapt themselves to
+the contour of the cylinder.
+
+
+WRIST PIN WEAR
+
+While wrist pins are usually made of very tough steel, case hardened
+with the object of wearing out an easily renewable bronze bushing in the
+upper end of the connecting rod rather than the wrist pin it sometimes
+happens that these members will be worn so that even the replacement of
+a new bushing in the connecting rod will not reduce the lost motion and
+attendant noise due to a loose wrist pin. The only remedy is to fit new
+wrist pins to the piston. Where the connecting rod is clamped to the
+wrist pin and that member oscillates in the piston bosses the wear will
+usually be indicated on bronze bushings which are pressed into the
+piston bosses. These are easily renewed and after running a reamer
+through them of the proper size no difficulty should be experienced in
+replacing either the old or a new wrist pin depending upon the condition
+of that member. If no bushings are provided, as in alloy pistons, the
+bosses can sometimes be bored out and thin bushings inserted, though
+this is not always possible. The alternative is to ream out the bosses
+and upper end of rod a trifle larger after holes are trued up and fit
+oversize wrist pins.
+
+
+INSPECTION AND REFITTING OF ENGINE BEARINGS
+
+While the engine is dismantled one has an excellent opportunity to
+examine the various bearing points in the engine crank-case to ascertain
+if any looseness exists due to depreciation of the bearing surfaces. As
+will be evident, both main crank-shaft bearings and the lower end of the
+connecting rods may be easily examined for deterioration. With the rods
+in place, it is not difficult to feel the amount of lost motion by
+grasping the connecting rod firmly with the hand and moving it up and
+down. After the connecting rods have been removed and the propeller hub
+taken off the crank-shaft to permit of ready handling, any looseness in
+the main bearing may be detected by lifting up on either the front or
+rear end of the crank-shaft and observing if there is any lost motion
+between the shaft journal and the main bearing caps. It is not necessary
+to take an engine entirely apart to examine the main bearings, as in
+most forms these may be readily reached by removing the sump. The
+symptoms of worn main bearings are not hard to identify. If an engine
+knocks regardless of speed or spark-lever position, and the trouble is
+not due to carbon deposits in the combustion chamber, one may reasonably
+surmise that the main bearings have become loose or that lost motion may
+exist at the connecting rod big ends, and possibly at the wrist pins.
+The main journals of any well resigned engine are usually proportioned
+with ample surface and will not wear unduly unless lubrication has been
+neglected. The connecting rod bearings wear quicker than the main
+bearings owing to being subjected to a greater unit stress, and it may
+be necessary to take these up.
+
+
+ADJUSTING MAIN BEARINGS
+
+[Illustration: Fig. 187.--Tools and Processes Used in Refitting Engine
+Bearings.]
+
+When the bearings are not worn enough to require refitting the lost
+motion can often be eliminated by removing one or more of the thin shims
+or liners ordinarily used to separate the bearing caps from the seat.
+These are shown at Fig. 187, A. Care must be taken that an even number
+of shims of the same thickness are removed from each side of the
+journal. If there is considerable lost motion after one or two shims
+have been removed, it will be advisable to take out more shims and to
+scrape the bearing to a fit before the bearing cap is tightened up. It
+may be necessary to clean up the crank-shaft journals as these may be
+scored due to not having received clean oil or having had bearings seize
+upon them. It is not difficult to true up the crank-pins or main
+journals if the score marks are not deep. A fine file and emery cloth
+may be used, or a lapping tool such as depicted at Fig. 187, B. The
+latter is preferable because the file and emery cloth will only tend to
+smooth the surface while the lap will have the effect of restoring the
+crank to proper contour.
+
+A lapping tool may be easily made, as shown at B, the blocks being of
+lead or hard wood. As the width of these are about half that of the
+crank-pin the tool may be worked from side to side as it is rotated. An
+abrasive paste composed of fine emery powder and oil is placed between
+the blocks, and the blocks are firmly clamped to the crank-pin. As the
+lead blocks bed down, the wing nut should be tightened to insure that
+the abrasive will be held with some degree of pressure against the
+shaft. A liberal supply of new abrading material is placed between the
+lapping blocks and crank-shaft from time to time and the old mixture
+cleaned off with gasoline. It is necessary to maintain a side to side
+movement of the lapping tool in order to have the process affect the
+whole width of the crank-pin equally. The lapping is continued until a
+smooth surface is obtained. If a crank-pin is worn out of true to any
+extent the only method of restoring it is to have it ground down to
+proper circular form by a competent mechanic having the necessary
+machine tools to carry on the work accurately. A crank-pin truing tool
+that may be worked by hand is shown at Fig. 187, K.
+
+After the crank-shaft is trued the next operation is to fit it to the
+main bearings or rather to scrape these members to fit the shaft
+journal. In order to bring the brasses closer together, it may be
+necessary to remove a little metal from the edges of the caps to
+compensate for the lost motion. A very simple way of doing this is shown
+at Fig. 187, D. A piece of medium emery cloth is rested on the surface
+plate and the box or brass is pushed back and forth over that member by
+hand, the amount of pressure and rapidity of movement being determined
+by the amount of metal it is necessary to remove. This is better than
+filing, because the edges will be flat and there will be no tendency
+for the bearing caps to rock when placed against the bearing seat. It is
+important to take enough off the edges of the boxes to insure that they
+will grip the crank tightly. The outer diameter must be checked with a
+pair of calipers during this operation to make sure that the surfaces
+remain parallel. Otherwise, the bearing brasses will only grip at one
+end and with such insufficient support they will quickly work loose,
+both in the bearing seat and bearing cap.
+
+
+SCRAPING BRASSES TO FIT
+
+To insure that the bearing brasses will be a good fit on the trued-up
+crank-pins or crank-shaft journals, they must be scraped to fit the
+various crank-shaft journals. The process of scraping, while a tedious
+one, is not difficult, requiring only patience and some degree of care
+to do a good job. The surface of the crank-pin is smeared with Prussian
+blue pigment which is spread evenly over the entire surface. The
+bearings are then clamped together in the usual manner with the proper
+bolts, and the crank-shaft revolved several times to indicate the high
+spots on the bearing cap. At the start of the process of scraping in,
+the bearing may seat only at a few points as shown at Fig. 187, G.
+Continued scraping will bring the bearing surface as indicated at H,
+which is a considerable improvement, while the process may be considered
+complete when the brass indicates a bearing all over as at I. The high
+spots are indicated by blue, as where the shaft does not bear on the
+bearing there is no color. The high spots are removed by means of a
+scraping tool of the form shown at Fig. 187, F, which is easily made
+from a worn-out file. These are forged to shape and ground hollow as
+indicated in the section, and are kept properly sharpened by frequent
+rubbing on an ordinary oil stone. To scrape properly, the edge of the
+scraper must be very keen. The straight and curved half-round scrapers,
+shown at M and N, are used for bearings. The three-cornered scraper,
+outlined at O, is also used on curved surfaces, and is of value in
+rounding off the sharp corners. The straight or curved half-round type
+works well on soft-bearing metals, such as babbitt, or white brass, but
+on yellow brass or bronze it cuts very slowly, and as soon as the edge
+becomes dull considerable pressure is needed to remove any metal, this
+calling for frequent sharpening.
+
+When correcting errors on flat or curved surfaces by hand-scraping, it
+is desirable, of course, to obtain an evenly spotted bearing with as
+little scraping as possible. When the part to be scraped is first
+applied to the surface-plate, or to a journal in the case of a bearing,
+three or four "high" spots may be indicated by the marking material. The
+time required to reduce these high spots and obtain a bearing that is
+distributed over the entire surface depends largely upon the way the
+scraping is started. If the first bearing marks indicate a decided rise
+in the surface, much time can be saved by scraping larger areas than are
+covered by the bearing marks; this is especially true of large shaft and
+engine bearings, etc. An experienced workman will not only remove the
+heavy marks, but also reduce a larger area; then, when the bearing is
+tested again, the marks will generally be distributed somewhat. If the
+heavy marks which usually appear at first are simply removed by light
+scraping, these "point bearings" are gradually enlarged, but a much
+longer time will be required to distribute them.
+
+The number of times the bearing must be applied to the journal for
+testing is important, especially when the box or bearing is large and
+not easily handled. The time required to distribute the bearing marks
+evenly depends largely upon one's judgment in "reading" these marks. In
+the early stages of the scraping operation, the marks should be used
+partly as a guide for showing the high areas, and instead of merely
+scraping the marked spot the surface surrounding it should also be
+reduced, unless it is evident that the unevenness is local. The idea
+should be to obtain first a few large but generally distributed marks;
+then an evenly and finely spotted surface can be produced quite easily.
+
+In fitting brasses when these are of the removable type, two methods may
+be used. The upper half of the engine base may be inverted on a suitable
+bench or stand and the boxes fitted by placing the crank-shaft in
+position, clamping down one bearing cap at a time and fitting each
+bearing in succession until they bed equally. From that time on the
+bearings should be fitted at the same time so the shaft will be parallel
+with the bottom of the cylinders. Considerable time and handling of the
+heavy crank-shaft may be saved if a preliminary fitting of the bearing
+brasses is made by clamping them together with a carpenter's wood clamp
+as shown at Fig. 187, J, and leaving the crank-shaft attached to the
+bench as shown at C. The brasses are revolved around the crank-shaft
+journal and are scraped to fit wherever high spots are indicated until
+they begin to seat fairly. When the brasses assume a finished appearance
+the final scraping should be carried on with all bearings in place and
+revolving the crank-shaft to determine the area of the seating. When the
+brasses are properly fitted they will not only show a full bearing
+surface, but the shaft will not turn unduly hard if revolved with a
+moderate amount of leverage.
+
+Bearings of white metal or babbitt can be fitted tighter than those of
+bronze, and care must be observed in supplying lubricant as considerably
+more than the usual amount is needed until the bearings are run in by
+several hours of test block work. Before the scraping process is started
+it is well to chisel an oil groove in the bearing as shown at Fig. 187,
+L. Grooves are very helpful in insuring uniform distribution of oil over
+the entire width of bearing and at the same time act as reservoirs to
+retain a supply of oil. The tool used is a round-nosed chisel, the
+effort being made to cut the grooves of uniform depth and having smooth
+sides. Care should be taken not to cut the grooves too deeply, as this
+will seriously reduce the strength of the bearing bushing. The shape of
+the groove ordinarily provided is clearly shown at Fig. 187, G, and it
+will be observed that the grooves do not extend clear to the edge of the
+bearing, but stop about a quarter of an inch from that point. The hole
+through which the oil is supplied to the bearing is usually drilled in
+such a way that it will communicate with the groove.
+
+The tool shown at Fig. 187, K, is of recent development, and is known as
+a "crank-shaft equalizer." This is a hand-operated turning tool,
+carrying cutters which are intended to smooth down scored crank-pins
+without using a lathe. The feed may be adjusted by suitable screws and
+the device may be fitted to crank-pins and shaft-journals of different
+diameters by other adjusting screws. This device is not hard to operate,
+being merely clamped around the crank-shaft in the same manner as the
+lapping tool previously described, and after it has been properly
+adjusted it is turned around by the levers provided for the purpose, the
+continuous rotary motion removing the metal just as a lathe tool would.
+
+
+FITTING CONNECTING RODS
+
+In the marine type rod, which is the form generally used in airplane
+engines, one or two bolts are employed at each side and the cap must be
+removed entirely before the bearing can be taken off of the crank-pin.
+The tightness of the brasses around the crank-pin can never be
+determined solely by the adjustment of the bolts, as while it is
+important that these should be drawn up as tightly as possible, the
+bearing should fit the shaft without undue binding, even if the brasses
+must be scraped to insure a proper fit. As is true of the main bearings,
+the marine form of connecting rod in some engines has a number of liners
+or shims interposed between the top and lower portions of the rod end,
+and these may be reduced in number when necessary to bring the brasses
+closer together. The general tendency in airplane engines is to
+eliminate shims in either the main or connecting rod bearings, and when
+wear is noticed the boxes or liners are removed and new ones supplied.
+The brasses are held in the connecting rod and cap by brass rivets and
+are generally attached in the main bearing by small brass machine
+screws. The form of box generally favored is a brass sand casting rich
+in copper to secure good heat conductivity which forms a backing for a
+thin layer of white brass, babbitt or similar anti-friction metal.
+
+[Illustration: Fig. 188.--Showing Points to Observe When Fitting
+Connecting Rod Brasses.]
+
+In fitting new brasses there are two conditions to be avoided, these
+being outlined at Fig. 188, B and C. In the case shown at C the light
+edges of the bushings are in contact, but the connecting rod and its cap
+do not meet. When the retaining nuts are tightened the entire strain is
+taken on the comparatively small area of the edges of the bushings which
+are not strong enough to withstand the strains existing and which
+flatten out quickly, permitting the bearing to run loose. In the example
+outlined at B the edges of the brasses do not touch when the connecting
+rod cap is drawn in place. This is not good practice, because the
+brasses soon become loose in their retaining member. In the case
+outlined it is necessary to file off the faces of the rod and cap until
+these meet, and to insure contact of the edges of the brasses as well.
+In event of the brasses coming together before the cap and rod make
+contact, as shown at C, the bearing halves should be reduced at the
+edges until both the caps and brasses meet against each other or the
+surfaces of the liners as shown at A.
+
+
+SPRUNG CAM-SHAFT
+
+If the cam-shaft is sprung or twisted it will alter the valve timing to
+such an extent that the smoothness of operation of the engine will be
+materially affected. If this condition is suspected the cam-shaft may be
+swung on lathe centers and turned to see if it runs out and can be
+straightened in any of the usual form of shaft-straightening machines.
+The shaft may be twisted without being sprung. This can only be
+determined by supporting one end of the shaft in an index head and the
+other end on a milling machine center. The cams are then checked to see
+that they are separated by the proper degree of angularity. This process
+is one that requires a thorough knowledge of the valve timing of the
+engine in question, and is best done at the factory where the engine was
+made. The timing gears should also be examined to see if the teeth are
+worn enough so that considerable back lash or lost motion exists between
+them. This is especially important where worm or spiral gears are used.
+A worn timing gear not only produces noise, but it will cause the time
+of opening and closing of the engine valves to vary materially.
+
+
+PRECAUTIONS IN REASSEMBLING PARTS
+
+When all of the essential components of a power plant have been
+carefully looked over and cleaned and all defects eliminated, either by
+adjustment or replacement of worn portions, the motor should be
+reassembled, taking care to have the parts occupy just the same
+relative positions they did before the motor was dismantled. As each
+part is added to the assemblage care should be taken to insure adequate
+lubrication of all new points of bearing by squirting liberal quantities
+of cylinder oil upon them with a hand oil can or syringe provided for
+the purpose. In adjusting the crank-shaft bearings, tighten them one at
+a time and revolve the shafts each time one of the bearing caps is set
+up to insure that the newly adjusted bearing does not have undue
+friction. All retaining keys and pins must be positively placed and it
+is good practice to cover such a part with lubricant before replacing it
+because it will not only drive in easier, but the part may be removed
+more easily if necessary at some future time. If not oiled, rust
+collects around it.
+
+When a piece is held by more than one bolt or screw, especially if it is
+a casting of brittle material such as cast iron or aluminum, the
+fastening bolts should be tightened uniformly. If one bolt is tightened
+more than the rest it is liable to spring the casting enough to break
+it. Spring washers, check nuts, split pins or other locking means should
+always be provided, especially on parts which are in motion or subjected
+to heavy loads.
+
+Before placing the cylinder over the piston it is imperative that the
+slots in the piston rings are spaced equidistant and that the piston is
+copiously oiled before the cylinder is slipped over it. When
+reassembling the inlet and exhaust manifolds it is well to use only
+perfect packings or gaskets and to avoid the use of those that seem to
+have hardened up or flattened out too much in service. If it is
+necessary to use new gaskets it is imperative to employ these at all
+joints on a manifold, because if old and new gaskets are used together
+the new ones are apt to keep the manifold from bedding properly upon the
+used ones. It is well to coat the threads of all bolts and screws
+subjected to heat, such as cylinder head and exhaust manifold retaining
+bolts, with a mixture of graphite and oil. Those that enter the water
+jacket should be covered with white or red lead or pipe thread
+compound. Gaskets will hold better if coated with shellac before the
+manifold or other parts are placed over them. The shellac fills any
+irregularities in the joint and assists materially in preventing leakage
+after the joint is made up and the coating has a chance to set.
+
+Before assembling on the shaft, it is necessary to fit the bearings by
+scraping, the same instructions given for restoring the contour of the
+main bearings applying just as well in this case. It is apparent that if
+the crank-pins are not round no amount of scraping will insure a true
+bearing. A point to observe is to make sure that the heads of the bolts
+are imbedded solidly in their proper position, and that they are not
+raised by any burrs or particles of dirt under the head which will
+flatten out after the engine has been run for a time and allow the bolts
+to slack off. Similarly, care should be taken that there is no foreign
+matter under the brasses and the box in which they seat. To guard
+against this the bolts should be struck with a hammer several times
+after they are tightened up, and the connecting rod can be hit sharply
+several times under the cap with a wooden mallet or lead hammer. It is
+important to pin the brasses in place to prevent movement, as
+lubrication may be interfered with if the bushing turns round and breaks
+the correct register between the oil hole in the cap and brasses.
+
+Care should be taken in screwing on the retaining nuts to insure that
+they will remain in place and not slack off. Spring washers should not
+be used on either connecting rod ends or main bearing nuts, because
+these sometimes snap in two pieces and leave the nut slack. The best
+method of locking is to use well-fitting split pins and castellated
+nuts.
+
+
+TESTING BEARING PARALLELISM
+
+It is not possible to give other than general directions regarding the
+proper degree of tightening for a connecting rod bearing, but as a guide
+to correct adjustment it may be said that if the connecting rod cap is
+tightened sufficiently so the connecting rod will just about fall over
+from a vertical position due to the piston weight when the bolts are
+fully tightened up, the adjustment will be nearly correct. As previously
+stated, babbitt or white metal bearings can be set up more tightly than
+bronze, as the metal is softer and any high spots will soon be leveled
+down with the running of the engine. It is important that care be taken
+to preserve parallelism of the wrist-pins and crank-shafts while
+scraping in bearings. This can be determined in two ways. That shown at
+Fig. 189, A, is used when the parts are not in the engine assembly and
+when the connecting rod bearing is being fitted to a mandrel or arbor
+the same size as the crank-pin. The arbor, which is finished very smooth
+and of uniform diameter, is placed in two V blocks, which in turn are
+supported by a level surface plate. An adjustable height gauge may be
+tried, first at one side of the wrist-pin which is placed at the upper
+end of the connecting rod, then at the other, and any variation will be
+easily determined by the degree of tilting of the rod. This test may be
+made with the wrist-pin alone, or if the piston is in place, a straight
+edge or spirit level may be employed. The spirit level will readily show
+any inclination while the straight edge is used in connection with the
+height gauge as indicated. Of course, the surface plate must be
+absolutely level when tests are made.
+
+When the connecting rods are being fitted with the crank-shaft in place
+in crank-case, and that member secured in the frame, a steel square may
+be used as it is reasonable to assume that the wrist-pin, and
+consequently the piston it carries, should observe a true relation with
+the top of the engine base. If the piston side is at right angles with
+the top of the engine base it is reasonable to assume that the wrist-pin
+and crank-pin are parallel. If the piston is canted to one side or the
+other, it will indicate that the brasses have been scraped tapering,
+which would mean considerable heating and undue friction if the piston
+is installed in the cylinder on account of the pressure against one
+portion of the cylinder wall. If the degree of canting is not too great,
+the connecting rods may be sprung very slightly to straighten up the
+piston, but this is a makeshift that is not advised. The height gauge
+method shown above may be used instead of the steel square, if desired,
+because the top of the crank-case is planed or milled true and should be
+parallel with the center line of the crank-shaft.
+
+[Illustration: Fig. 189.--Methods of Testing to Insure Parallelism of
+Bearings After Fitting.]
+
+
+CAM-SHAFTS AND TIMING GEARS
+
+Knocking sounds are also evident if the cam-shaft is loose in its
+bearings, and also if the cams or timing gears are loose on the shaft.
+The cam-shaft is usually supported by solid bearings of the removable
+bushing type, having no compensation for depreciation. If these bearings
+wear the only remedy is replacement with new ones. In the older makes of
+cars it was general practice to machine the cams separately and to
+secure these to the cam-shaft by means of taper pins or keys. These
+members sometimes loosened and caused noise. In the event of the cams
+being loose, care should be taken to use new keys or taper pins, as the
+case may be. If the fastening used was a pin, the hole through the
+cam-shaft will invariably be slightly oval from wear. In order to insure
+a tight job, the holes in cam and shaft must be reamed with the next
+larger size of standard taper reamer and a larger pin driven in. Another
+point to watch is the method of retaining the cam-shaft gear in place.
+On some engines the gear is fastened to a flange on the cam-shaft by
+retaining screws. These are not apt to become loose, but where reliance
+is placed on a key the cam-shaft gear may often be loose on its
+supporting member. The only remedy is to enlarge the key slot in both
+gear and shaft and to fit a larger retaining key.
+
+
+
+
+CHAPTER XII
+
+ Aviation Engine Types--Division in Classes--Anzani Engines--
+ Canton and Unne Engine--Construction of Gnome Engines--
+ "Monosoupape" Gnome--German "Gnome" Type--Le Rhone Engine--
+ Renault Air-Cooled Engine--Simplex Model "A" Hispano-Suiza--
+ Curtiss Aviation Motors--Thomas-Morse Model 88 Engine--
+ Duesenberg Engine--Aeromarine Six-Cylinder--Wisconsin Aviation
+ Engines--Hall-Scott Engines--Mercedes Motor--Benz Motor--
+ Austro-Daimler--Sunbeam-Coatalen.
+
+
+AVIATION ENGINE TYPES
+
+Inasmuch as numerous forms of airplane engines have been devised, it
+would require a volume of considerable size to describe even the most
+important developments of recent years. As considerable explanatory
+matter has been given in preceding chapters and the principles involved
+in internal combustion engine operation considered in detail, a
+relatively brief review of the features of some of the most successful
+airplane motors should suffice to give the reader a complete enough
+understanding of the art so all types of engines can be readily
+recognized and the advantages and disadvantages of each type understood,
+as well as defining the constructional features enough so the methods of
+locating and repairing the common engine and auxiliary system troubles
+will be fully grasped.
+
+Aviation engines can be divided into three main classes. One of the
+earliest attempts to devise distinctive power plant designs for aircraft
+involved the construction of engines utilizing a radial arrangement of
+the cylinders or a star-wise disposition. Among the engines of this
+class may be mentioned the Anzani, R. E. P. and the Salmson or Canton
+and Unne forms. The two former are air-cooled, the latter design is
+water-cooled. Engines of this type have been built in cylinder numbers
+ranging from three to twenty. While the simple forms were popular in the
+early days of aviation engine development, they have been succeeded by
+the more conventional arrangements which now form the largest class. The
+reason for the adoption of a star-wise arrangement of cylinders has been
+previously considered. Smoothness of running can only be obtained by
+using a considerable number of cylinders. The fundamental reason for the
+adoption of the star-wise disposition is that a better distribution of
+stress is obtained by having all of the pistons acting on the same
+crank-pin so that the crank-throw and pin are continuously under maximum
+stress. Some difficulty has been experienced in lubricating the lower
+cylinders in some forms of six cylinder, rotary crank, radial engines
+but these have been largely overcome so they are not as serious in
+practice as a theoretical consideration would indicate.
+
+Another class of engines developed to meet aviation requirements is a
+complete departure from the preceding class, though when the engines are
+at rest, it is difficult to differentiate between them. This class
+includes engines having a star-wise disposition of the cylinders but the
+cylinders themselves and the crank-case rotate and the crank-shaft
+remains stationary. The important rotary engines are the Gnome, the Le
+Rhone and the Clerget. By far the most important classification is that
+including engines which retain the approved design of the types of power
+plants that have been so widely utilized in automobiles and which have
+but slight modifications to increase reliability and mechanical strength
+and produce a reduction in weight. This class includes the vertical
+engines such as the Duesenberg and Hall-Scott four-cylinder; the
+Wisconsin, Aeromarine, Mercedes, Benz, and Hall-Scott six-cylinder
+vertical engines and the numerous eight- and twelve-cylinder Vee designs
+such as the Curtiss, Renault, Thomas-Morse, Sturtevant, Sunbeam, and
+others.
+
+
+ANZANI ENGINES
+
+The attention of the mechanical world was first directed to the great
+possibilities of mechanical flight when Bleriot crossed the English
+Channel in July, 1909, in a monoplane of his own design and
+construction, having the power furnished by a small three-cylinder
+air-cooled engine rated at about 24 horse-power and having cylinders
+4.13 inches bore and 5.12 inches stroke, stated to develop the power at
+about 1600 R.P.M. and weighing 145 pounds. The arrangement of this early
+Anzani engine is shown at Fig. 190, and it will be apparent that in the
+main, the lines worked out in motorcycle practice were followed to a
+large extent. The crank-case was of the usual vertically divided
+pattern, the cylinders and heads being cast in one piece and held to the
+crank-case by stud bolts passing through substantial flanges at the
+cylinder base. In order to utilize but a single crank-pin for the three
+cylinders it was necessary to use two forked rods and one rod of the
+conventional type. The arrangement shown at Fig. 190, called for the use
+of counter-balanced flywheels which were built up in connection with
+shafts and a crank-pin to form what corresponds to the usual crank-shaft
+assembly.
+
+[Illustration: Fig. 190.--Views Outlining Construction of Three-Cylinder
+Anzani Aviation Motor.]
+
+The inlet valves were of the automatic type so that a very simple valve
+mechanism consisting only of the exhaust valve push rods was provided.
+One of the difficulties of this arrangement of cylinders was that the
+impulses are not evenly spaced. For instance, in the forms where the
+cylinders were placed 60 degrees apart the space between the firing of
+the first cylinder and that next in order was 120 degrees crank-shaft
+rotation, after which there was an interval of 300 degrees before the
+last cylinder to fire delivered its power stroke. In order to increase
+the power given by the simple three-cylinder air-cooled engine a
+six-cylinder water-cooled type, as shown at Figs. 191 and 192, was
+devised. This was practically the same in action as the three-cylinder
+except that a double throw crank-shaft was used and while the
+explosions were not evenly spaced the number of explosions obtained
+resulted in fairly uniform application of power.
+
+[Illustration: Fig. 190a.--Illustrations Depicting Wrong and Right
+Methods of "Swinging the Stick" to Start Airplane Engine. At Top, Poor
+Position to Get Full Throw and Get Out of the Way. Below, Correct
+Position to Get Quick Turn Over of Crank-Shaft and Spring Away from
+Propeller.]
+
+[Illustration: Fig. 191.--The Anzani Six-Cylinder Water-Cooled Aviation
+Engine.]
+
+[Illustration: Fig. 192.--Sectional View of Anzani Six-Cylinder
+Water-Cooled Aviation Engine.]
+
+The latest design of three-cylinder Anzani engine, which is used to some
+extent for school machines, is shown at Fig. 193. In this, the
+three-cylinders are symmetrically arranged about the crank-case or 120
+degrees apart. The balance is greatly improved by this arrangement and
+the power strokes occur at equal intervals of 240 degrees of crank-shaft
+rotation. This method of construction is known as the Y design. By
+grouping two of these engines together, as outlined at Fig. 194, which
+gives an internal view, and at Fig. 195, which shows the sectional view,
+and using the ordinary form of double throw crank-shaft with crank-pins
+separated by 180 degrees, a six-cylinder radial engine is produced which
+runs very quietly and furnishes a steady output of power. The
+peculiarity of the construction of this engine is in the method of
+grouping the connecting rod about the common crank-pin without using
+forked rods or the "Mother rod" system employed in the Gnome engines. In
+the Anzani the method followed is to provide each connecting rod big end
+with a shoe which consists of a portion of a hollow cylinder held
+against the crank-pin by split clamping rings. The dimensions of these
+shoes are so proportioned that the two adjacent connecting rods of a
+group of three will not come into contact even when the connecting rods
+are at the minimum relative angle. The three shoes of each group rest
+upon a bronze sleeve which is in halves and which surrounds the
+crank-pin and rotates relatively to it once in each crank-shaft
+revolution. The collars, which are of tough bronze, resist the inertia
+forces while the direct pressure of the explosions is transmitted
+directly to the crank-pin bushing by the shoes at the big end of the
+connecting rod. The same method of construction, modified to some
+extent, is used in the Le Rhone rotary cylinder engine.
+
+[Illustration: Fig. 193.--Three-Cylinder Anzani Air-Cooled Y-Form
+Engine.]
+
+[Illustration: Fig. 194.--Anzani Fixed Crank-Case Engine of the
+Six-Cylinder Form Utilizes Air Cooling Successfully.]
+
+Both cylinders and pistons of the Anzani engines are of cast iron, the
+cylinders being provided with a liberal number of cooling flanges which
+are cast integrally. A series of auxiliary exhaust ports is drilled near
+the base of each cylinder so that a portion of the exhaust gases will
+flow out of the cylinder when the piston reaches the end of its power
+stroke. This reduces the temperature of the gases passing around the
+exhaust valves and prevents warping of these members. Another
+distinctive feature of this engine design is the method of attaching the
+Zenith carburetor to an annular chamber surrounding the rear portion of
+the crank-case from which the intake pipes leading to the intake valves
+radiate. The magneto is the usual six-cylinder form having the armature
+geared to revolve at one and one-half times crank-shaft speed.
+
+[Illustration: Fig. 195.--Sectional View Showing Internal Parts of
+Six-Cylinder Anzani Engine, with Starwise Disposition of Cylinders.]
+
+[Illustration: Fig. 196.--The Anzani Ten-Cylinder Aviation Engine at
+the Left, and the Twenty-Cylinder Fixed Type at the Right.]
+
+The Anzani aviation engines are also made in ten- and twenty-cylinder
+forms as shown at Fig. 196. It will be apparent that in the
+ten-cylinder form explosions will occur every 72 degrees of crank-shaft
+rotation, while in the twenty-cylinder, 200 horse-power engine at any
+instant five of the cylinders are always working and explosions are
+occurring every 36 degrees of crank-shaft rotation. On the
+twenty-cylinder engine, two carburetors are used and two magnetos,
+which are driven at two and one-half times crank-shaft speed. The
+general cylinder and valve construction is practically the same, as in
+the simpler engines.
+
+[Illustration: Fig. 197.--Application of R. E. P. Five-Cylinder
+Fan-Shape Air-Cooled Motor to Early Monoplane.]
+
+
+CANTON AND UNNE ENGINE
+
+This engine, which has been devised specially for aviation service, is
+generally known as the "Salmson" and is manufactured in both France and
+Great Britain. It is a nine-cylinder water-cooled radial engine, the
+nine cylinders being symmetrically disposed around the crank-shaft while
+the nine connecting rods all operate on a common crank-pin in somewhat
+the same manner as the rods in the Gnome motor. The crank-shaft of the
+Salmson engine is not a fixed one and inasmuch as the cylinders do not
+rotate about the crank-shaft it is necessary for that member to revolve
+as in the conventional engine. The stout hollow steel crank-shaft is in
+two pieces and has a single throw. The crank-shaft is built up somewhat
+the same as that of the Gnome engine. Ball bearings are used throughout
+this engine as will be evident by inspecting the sectional view given at
+Fig. 199. The nine steel connecting rods are machined all over and are
+fitted at each end with bronze bushings, the distance between the
+bearing centers being about 3.25 times crank length. The method of
+connecting up the rods to the crank-pin is one of the characteristic
+features of this design. No "mother" rod as supplied in the Gnome engine
+is used in this type inasmuch as the steel cage or connecting rod
+carrier is fitted with symmetrically disposed big end retaining pins.
+Inasmuch as the carrier is mounted on ball bearings some means must be
+provided of regulating the motion of the carrier as if no means were
+provided the resulting motion of the pistons would be irregular.
+
+[Illustration: Fig. 198.--The Canton and Unne Nine-Cylinder Water-Cooled
+Radial Engine.]
+
+The method by which the piston strokes are made to occur at precise
+intervals involves a somewhat lengthy and detailed technical
+explanation. It is sufficient to say that an epicyclic train of gears,
+one of which is rigidly attached to the crank-case so it cannot rotate
+is used, while other gears make a connection between the fixed gear and
+with another gear which is exactly the same size as the fixed gear
+attached to the crank-case and which is formed integrally with the
+connecting rod carrier. The action of the gearing is such that the cage
+carrying the big end retaining pins does not rotate independently of
+the crank-shaft, though, of course, the crank-shaft or rather crank-pin
+bearings must turn inside of the big end carrier cage.
+
+[Illustration: Fig. 199.--Sectional View Showing Construction of Canton
+and Unne Water-Cooled Radial Cylinder Engine.]
+
+Cylinders of this engine are of nickel steel machined all over and carry
+water-jackets of spun copper which are attached to the cylinders by
+brazing. The water jackets are corrugated to permit the cylinder to
+expand freely. The ignition is similar to that of the fixed crank
+rotating cylinder engine. An ordinary magneto of the two spark type
+driven at 1-3/4 times crank-shaft speed is sufficient to ignite the
+seven-cylinder form, while in the nine-cylinder engines the ignition
+magneto is of the "shield" type giving four sparks per revolution. The
+magneto is driven at 1-1/9 times crank-shaft speed. Nickel steel valves
+are used and are carried in castings or cages which screw into bosses in
+the cylinder head. Each valve is cam operated through a tappet, push rod
+and rocker arm, seven cams being used on a seven-cylinder engine and
+nine cams on the nine-cylinder. One cam serves to open both valves as in
+its rotation it lifts the tappets in succession and so operates the
+exhaust and inlet valves respectively. This method of operation involves
+the same period of intake and exhaust. In normal engine practice the
+inlet valve opens 12 degrees late and closes 20 degrees late. The
+exhaust opens 45 degrees early and closes 6 degrees late. This means
+about 188 degrees in the case of inlet valve and 231 degrees crank-shaft
+travel for exhaust valves. In the Salmson engine, the exhaust closes and
+the inlet opens at the outer dead center and the exhaust opens and the
+inlet closes at about the inner dead center. This engine is also made in
+a fourteen-cylinder 200 B. H. P. design which is composed of two groups
+of seven-cylinders, and it has been made in an eighteen-cylinder design
+of 600 horse-power. The nine-cylinder 130 horse-power has a cylinder
+bore of 4.73 inches and a stroke of 5.52 inches. Its normal speed of
+rotation is 1250 R. P. M. Owing to the radial arrangement of the
+cylinders, the weight is but 4-1/4 pounds per B. H. P.
+
+
+CONSTRUCTION OF EARLY GNOME MOTOR
+
+It cannot be denied that for a time one of the most widely used of
+aeroplane motors was the seven-cylinder revolving air-cooled Gnome, made
+in France. For a total weight of 167 pounds this motor developed 45 to
+47 horse-power at 1,000 revolutions, being equal to 3.35 pounds per
+horse-power, and has proved its reliability by securing many
+long-distance and endurance records. The same engineers have produced
+a nine-cylinder and by combining two single engines a fourteen-cylinder
+revolving Gnome, having a nominal rating of 100 horse-power, with which
+world's speed records were broken. A still more powerful engine has been
+made with eighteen-cylinders. The nine-cylinder "monosoupape" delivers
+100 horse-power at 1200 R. P. M., the engine of double that number of
+cylinders is rated at about 180 horse-power.
+
+[Illustration: Fig. 200.--Sectional View Outlining Construction of Early
+Type Gnome Valve-in-Piston Type Motor.]
+
+Except in the number of cylinders and a few mechanical details the
+fourteen-cylinder motor is identical with the seven-cylinder one; fully
+three-quarters of the parts used by the assemblers would do just as well
+for one motor as for the other. Owing to the greater power demands of
+the modern airplane the smaller sizes of Gnome engines are not used as
+much as they were except for school machines. There is very little in
+this motor that is common to the standard type of vertical motorcar
+engine. The cylinders are mounted radially round a circular crank-case;
+the crank-shaft is fixed, and the entire mass of cylinders and
+crank-case revolves around it as outlined at Fig. 200. The explosive
+mixture and the lubricating oil are admitted through the fixed hollow
+crank-shaft, passed into the explosion chamber through an automatic
+intake valve in the piston head in the early pattern, and the spent
+gases exhausted through a mechanically operated valve in the cylinder
+head. The course of the gases is practically a radial one. A peculiarity
+of the construction of the motor is that nickel steel is used
+throughout. Aluminum is employed for the two oil pump housings; the
+single compression ring known as the "obdurator" for each piston is made
+of brass; there are three or four brass bushes; gun metal is employed
+for certain pins--the rest is machined out of chrome nickel steel. The
+crank-case is practically a steel hoop, the depth depending on whether
+it has to receive seven-or fourteen-cylinders; it has seven or fourteen
+holes bored as illustrated on its circumference. When fourteen or
+eighteen cylinders are used the holes are bored in two distinct planes,
+and offset in relation one to the other.
+
+The cylinders of the small engine which have a bore of 4-3/10 inches and
+a stroke of 4-7/10 inches, are machined out of the solid bar of steel
+until the thickness of the walls is only 1.5 millimeters--.05905 inch,
+or practically 1/16 inch. Each one has twenty-two fins which gradually
+taper down as the region of greatest pressure is departed from. In
+addition to carrying away heat, the fins assist in strengthening the
+walls of the cylinder. The barrel of the cylinder is slipped into the
+hole bored for it on the circumference of the crank-case and secured by
+a locking member in the nature of a stout compression ring, sprung onto
+a groove on the base of the cylinder within the crank chamber. On each
+lateral face of the crank chamber are seven holes, drilled right through
+the chamber parallel with the crank-shaft. Each one of these holes
+receives a stout locking-pin of such a diameter that it presses against
+the split rings of two adjacent cylinders; in addition each cylinder is
+fitted with a key-way. This construction is not always followed, some of
+the early Gnome engines using the same system of cylinder retention as
+used on the latest "monosoupape" pattern.
+
+The exhaust valve is mounted in the cylinder head, Fig. 201, its seating
+being screwed in by means of a special box spanner. On the
+fourteen-cylinder model the valve is operated directly by an overhead
+rocker arm with a gun metal rocker at its extremity coming in contact
+with the extremity of the valve stem. As in standard motor car practice,
+the valve is opened under the lift of the vertical push rod, actuated by
+the cam. The distinctive feature is the use of a four-blade leaf spring
+with a forked end encircling the valve stems and pressing against a
+collar on its extremity. On the seven-cylinder model the movement is
+reversed, the valve being opened on the downward pull of the push rod,
+this lifting the outer extremity of the main rocker arm, which tips a
+secondary and smaller rocker arm in direct contact with the extremity
+of the valve stem. The springs are the same in each case. The two types
+are compared at A and B, Fig. 202.
+
+[Illustration: Fig. 201.--Sectional View of Early Type Gnome Cylinder
+and Piston Showing Construction and Application of Inlet and Exhaust
+Valves.]
+
+The pistons, like the cylinders, are machined out of the solid bar of
+nickel steel, and have a portion of their wall cut away, so that the two
+adjacent ones will not come together at the extremity of their stroke.
+The head of the piston is slightly reduced in diameter and is provided
+with a groove into which is fitted a very light L-section brass split
+ring; back of this ring and carried within the groove is sprung a light
+steel compression ring, serving to keep the brass ring in expansion. As
+already mentioned, the intake valves are automatic, and are mounted in
+the head of the piston as outlined at Fig. 202, C. The valve seating is
+in halves, the lower portion being made to receive the wrist-pin and
+connecting rod, and the upper portion, carrying the valve, being screwed
+into it. The spring is composed of four flat blades, with the hollowed
+stem of the automatic valve passing through their center and their two
+extremities attached to small levers calculated to give balance against
+centrifugal force. The springs are naturally within the piston, and are
+lubricated by splash from the crank chamber. They are of a delicate
+construction, for it is necessary that they shall be accurately balanced
+so as to have no tendency to fly open under the action of centrifugal
+force. The intake valve is withdrawn by the use of special tools through
+the cylinder head, the exhaust valve being first dismounted.
+
+[Illustration: Fig. 202.--Details of Old Style Gnome Motor Inlet and
+Exhaust Valve Construction and Operation.]
+
+The fourteen-cylinder motor shown at Fig. 203, has a two-throw
+crank-shaft with the throws placed at 180 degrees, each one receiving
+seven connecting rods. The parts are the same as for the seven-cylinder
+motor, the larger one consisting of two groups placed side by side. For
+each group of seven-cylinders there is one main connecting rod, together
+with six auxiliary rods. The main connecting rod, which, like the
+others, is of H section, has machined with it two L-section rings bored
+with six holes--51-1/2 degrees apart to take the six other connecting
+rods. The cage of the main connecting rod carries two ball races, one on
+either side, fitting onto the crank-pin and receiving the thrust of the
+seven connecting rods. The auxiliary connecting rods are secured in
+position in each case by a hollow steel pin passing through the two
+rings. It is evident that there is a slightly greater angularity for the
+six shorter rods, known as auxiliary connecting rods, than for the
+longer main rods; this does not appear to have any influence on the
+running of the motor.
+
+[Illustration: Fig. 203.--The Gnome Fourteen-Cylinder 100 Horse-Power
+Aviation Engine.]
+
+Coming to the manner in which the earliest design exhaust valves are
+operated on the old style motor, this at first sight appears to be one
+of the most complicated parts of the motor, probably because it is one
+in which standard practice is most widely departed from. Within the
+cylindrical casing bolted to the rear face of the crank-case are seven,
+thin flat-faced steel rings, forming female cams. Across a diameter of
+each ring is a pair of projecting rods fitting in brass guides and
+having their extremities terminating in a knuckle eye receiving the
+adjustable push rods operating the overhead rocker arms of the exhaust
+valve. The guides are not all in the same plane, the difference being
+equal to the thickness of the steel rings, the total thickness being
+practically 2 inches. Within the female cams is a group of seven male
+cams of the same total thickness as the former and rotating within them.
+As the boss of the male cam comes into contact with the flattened
+portion of the ring forming the female cam, the arm is pushed outward
+and the exhaust valve opened through the medium of the push-rod and
+overhead rocker. This construction was afterwards changed to seven male
+cams and simple valve operating plunger and roller cam followers as
+shown at Fig. 204.
+
+On the face of the crank-case of the fourteen-cylinder motor opposite to
+the valve mechanism is a bolted-on end plate, carrying a pinion for
+driving the two magnetos and the two oil pumps, and having bolted to it
+the distributor for the high-tension current. Each group of
+seven-cylinders has its own magneto and lubricating pump. The two
+magnetos and the two pumps are mounted on the fixed platform carrying
+the stationary crank-shaft, being driven by the pinion on the revolving
+crank chamber. The magnetos are geared up in the proportion of 4 to 7.
+Mounted on the end plate back of the driving pinion are the two
+high-tension distributor plates, each one with seven brass segments let
+into it and connection made to the plugs by means of plain brass wire.
+The wire passes through a hole in the plug and is then wrapped round
+itself, giving a loose connection.
+
+[Illustration: Fig. 204.--Cam and Cam-Gear Case of the Gnome
+Seven-Cylinder Revolving Engine.]
+
+[Illustration: Fig. 205.--Diagrams Showing Why An Odd Number of
+Cylinders is Best for Rotary Cylinder Motors.]
+
+A good many people doubtless wonder why rotary engines are usually
+provided with an odd number of cylinders in preference to an even
+number. It is a matter of even torque, as can easily be understood from
+the accompanying diagram. Fig. 205, A, represents a six-cylinder rotary
+engine, the radial lines indicating the cylinders. It is possible to
+fire the charges in two ways, firstly, in rotation, 1, 2, 3, 4, 5, 6,
+thus having six impulses in one revolution and none in the next; or
+alternately, 1, 3, 5, 2, 4, 6, in which case the engine will have turned
+through an equal number of degrees between impulses 1 and 3, and 3 and
+5, but a greater number between 5 and 2, even again between 2 and 4, 4
+and 6, and a less number between 6 and 1, as will be clearly seen on
+reference to the diagram. Turning to Fig. 205, B, which represents a
+seven-cylinder engine. If the cylinders fire alternately it is obvious
+that the engine turns through an equal number of degrees between each
+impulse, thus, 1, 3, 5, 7, 2, 4, 6, 1, 3, etc. Thus supposing the engine
+to be revolving, the explosion takes place as each alternate cylinder
+passes, for instance, the point 1 on the diagram, and the ignition is
+actually operated in this way by a single contact.
+
+[Illustration: Fig. 206.--Simple Carburetor Used On Early Gnome Engines
+Attached to Fixed Crank-Shaft End.]
+
+The crank-shaft of the Gnome, as already explained, is fixed and hollow.
+For the seven- and nine-cylinder motors it has a single throw, and for
+the fourteen- and eighteen-cylinder models has two throws at 180
+degrees. It is of the built-up type, this being necessary on account of
+the distinctive mounting of the connecting rods. The carburetor shown at
+Fig. 206 is mounted at one end of the stationary crank-shaft, and the
+mixture is drawn in through a valve in the piston as already explained.
+There is neither float chamber nor jet. In many of the tests made at the
+factory it is said the motor will run with the extremity of the gasoline
+pipe pushed into the hollow crank-shaft, speed being regulated entirely
+by increasing or decreasing the flow through the shut-off valve in the
+base of the tank. Even under these conditions the motor has been
+throttled down to run at 350 revolutions without misfiring. Its normal
+speed is 1,000 to 1,200 revolutions a minute. Castor oil is used for
+lubricating the engine, the oil being injected into the hollow
+crank-shaft through slight-feed fittings by a mechanically operated pump
+which is clearly shown in sectional diagrams at Fig. 207.
+
+[Illustration: Fig. 207.--Sectional Views of the Gnome Oil Pump.]
+
+The Gnome is a considerable consumer of lubricant, the makers' estimate
+being 7 pints an hour for the 100 horse-power motor; but in practice
+this is largely exceeded. The gasoline consumption is given as 300 to
+350 grammes per horse-power. The total weight of the fourteen-cylinder
+motor is 220 pounds without fuel or lubricating oil. Its full power is
+developed at 1,200 revolutions, and at this speed about 9 horse-power is
+lost in overcoming air resistance to cylinder rotation.
+
+[Illustration: Fig. 208.--Simplified Diagram Showing Gnome Motor Magneto
+Ignition System.]
+
+While the Gnome engine has many advantages, on the other hand, the head
+resistance offered by a motor of this type is considerable; there is a
+large waste of lubricating oil due to the centrifugal force which tends
+to throw the oil away from the cylinders; the gyroscopic effect of the
+rotary motor is detrimental to the best working of the aeroplane, and
+moreover it requires about seven per cent. of the total power developed
+by the motor to drive the revolving cylinders around the shaft. Of
+necessity, the compression of this type of motor is rather low, and an
+additional disadvantage manifests itself in the fact that there is as
+yet no satisfactory way of muffling the rotary type of motor.
+
+
+GNOME "MONOSOUPAPE" TYPE
+
+The latest type of Gnome engine is known as the "monosoupape" type
+because but one valve is used in the cylinder head, the inlet valve in
+the piston being dispensed with on account of the trouble caused by that
+member on earlier engines. The construction of this latest type follows
+the lines established in the earlier designs to some extent and it
+differs only in the method of charging. The very rich mixture of gas and
+air is forced into the crank-case through the jet inside the
+crank-shaft, and enters the cylinder when the piston is at its lowest
+position, through the half-round openings in the guiding flange and the
+small holes or ports machined in the cylinder and clearly shown at Fig.
+210. The returning piston covers the port, and the gas is compressed and
+fired in the usual way. The exhaust is through a large single valve in
+the cylinder head, which gives rise to the name "monosoupape," or
+single-valve motor, and this valve also remains open a portion of the
+intake stroke to admit air into the cylinder and dilute the rich gas
+forced in from the crank-case interior. Aviators who have used the early
+form of Gnome say that the inlet valve in the piston type was prone to
+catch on fire if any valve defect materialized, but the "monosoupape"
+pattern is said to be nearly free of this danger. The bore of the 100
+horse-power nine-cylinder engine is 110 mm., the piston stroke 150 mm.
+Extremely careful machine work and fitting is necessary. In many parts,
+tolerances of less than .0004" (four ten thousandths of an inch) are all
+that are allowed. This is about one-sixth the thickness of the average
+human hair, and in other parts the size must be absolutely standard, no
+appreciable variation being allowable. The manufacture of this engine
+establishes new mechanical standards of engine production in this
+country. Much machine work is needed in producing the finished
+components from the bar and forging.
+
+[Illustration: Fig. 209.--The G. V. Gnome "Monosoupape" Nine-Cylinder
+Rotary Engine Mounted on Testing Stand.]
+
+[Illustration: Fig. 210.--Sectional View Showing Construction of General
+Vehicle Co. "Monosoupape" Gnome Engine.]
+
+The cylinders, for example, are machined from 6 inch solid steel bars,
+which are sawed into blanks 11 inches in length and weighing about 97
+pounds. The first operation is to drill a 2-1/16 inch hole through the
+center of the block. A heavy-duty drilling machine performs this work,
+then the block goes to the lathe for further operations. Fig. 211 shows
+six stages of the progress of a cylinder, a few of the intermediate
+steps being omitted. These give, however, a good idea of the work done.
+The turning of the gills, or cooling flanges, is a difficult
+proposition, owing to the depth of the cut and the thin metal that forms
+the gills. This operation requires the utmost care of tools and the use
+of a good lubricant to prevent the metal from tearing as the tools
+approach their full depth. These gills are only 0.6 mm., or 0.0237 in.,
+thick at the top, tapering to a thickness of 1.4 mm. (0.0553 in.) at the
+base, and are 16 mm. (0.632 in.) deep. When the machine work is
+completed the cylinder weighs but 5-1/2 pounds.
+
+[Illustration: Fig. 211.--How a Gnome Cylinder is Reduced from Solid
+Chunk of Steel Weighing 97 Pounds to Finished Cylinder Weighing 5-1/2
+Pounds.]
+
+
+GNOME FUEL SYSTEM, IGNITION AND LUBRICATION
+
+The following description of the fuel supply, ignition and oiling of the
+"monosoupape," or single valve Gnome, is taken from "The Automobile."
+
+Gasoline is fed to the engine by means of air pressure at 5 pounds per
+sq. in., which is produced by the air pump on the engine clearly shown
+at Fig. 210. A pressure gauge convenient to the operator indicates this
+pressure, and a valve enables the operator to control it. No carburetor
+is used. The gasoline flows from the tank through a shut-off valve near
+the operator and through a tube leading through the hollow crank-shaft
+to a spray nozzle located in the crank-case. There is no throttle valve,
+and as each cylinder always receives the same amount of air as long as
+the atmospheric pressure is the same, the output cannot be varied by
+reducing the fuel supply, except within narrow limits. A fuel capacity
+of 65 gallons is provided. The fuel consumption is at the rate of 12 U.
+S. gallons per hour.
+
+The high-tension magnetos, with double cam or two break per revolution
+interrupter, is located on the thrust plate in an inverted position, and
+is driven at such a speed as to produce nine sparks for every two
+revolutions; that is, at 2-1/4 times engine speed. A Splitdorf magneto
+is fitted. There is no distributor on the magneto. The high-tension
+collector brush of the magneto is connected to a distributor brush
+holder carried in the bearer plate of the engine. The brush in this
+brush holder is pressed against a distributor ring of insulating
+material molded in position in the web of a gear wheel keyed to the
+thrust plate, which gear serves also for starting the engine by hand.
+Molded in this ring of insulating material are nine brass contact
+sectors, connecting with contact screws at the back side of the gear,
+from which bare wires connect to the spark-plugs. The distributor
+revolves at engine speed, instead of at half engine speed as on ordinary
+engines, and the distributor brush is brought into electrical connection
+with each spark-plug every time the piston in the cylinder in which this
+spark-plug is located approaches the outer dead center. However, on the
+exhaust stroke no spark is being generated in the magneto, hence none is
+produced at the spark-plug.
+
+[Illustration: Fig. 212.--The Gnome Engine Cam-Gear Case, a Fine Example
+of Accurate Machine Work.]
+
+Ordinarily the engine is started by turning on the propeller, but for
+emergency purposes as in seaplanes or for a quick "get away" if landing
+inadvertently in enemy territory, a hand starting crank is provided.
+This is supported in bearings secured to the pressed steel carriers of
+the engine and is provided with a universal joint between the two
+supports so as to prevent binding of the crank in the bearings due to
+possible distortion of the supports. The gear on this starting crank and
+the one on the thrust plate with which it meshes are cut with helical
+teeth of such hand that the starting pinion is thrown out of mesh as
+soon as the engine picks up its cycle. A coiled spring surrounds part of
+the shaft of the starting crank and holds it out of gear when not in
+use.
+
+[Illustration: Fig. 213.--G. V. Gnome "Monosoupape," with Cam-Case Cover
+Removed to Show Cams and Valve-Operating Plungers with Roller Cam
+Followers.]
+
+Lubricating oil is carried in a tank of 25 gallon capacity, and if this
+tank has to be placed in a low position it is connected with the
+air-pressure line, so that the suction of the oil pump is not depended
+upon to get the oil to the pump. From the bottom of the oil tank a pipe
+leads to the pump inlet. There are two outlets from the pump, each
+entering the hollow crank-shaft, and there is a branch from each outlet
+pipe to a circulation indicator convenient to the operator. One of the
+oil leads feeds to the housing in the thrust plate containing the two
+rear ball bearings, and the other lead feeds through the crank-pin to
+the cams, as already explained.
+
+Owing to the effect of centrifugal force and the fact that the oil is
+not used over again, the oil consumption of a revolving cylinder engine
+is considerably higher than that of a stationary cylinder engine. Fuel
+consumption is also somewhat higher, and for this reason the revolving
+cylinder engine is not so well suited for types of airplanes designed
+for long trips, as the increased weight of supplies required for such
+trips, as compared with stationary cylinder type motors, more than
+offsets the high weight efficiency of the engine itself. But for short
+trips, and especially where high speed is required, as in single seated
+scout and battle planes or "avions de chasse," as the French say, the
+revolving cylinder engine has the advantage. The oil consumption of the
+Gnome engine is as high as 2.4 gallon per hour. Castor oil is used for
+lubrication because it is not cut by the gasoline mist present in the
+engine interior as an oil of mineral derivation would be.
+
+
+GERMAN "GNOME" TYPE ENGINE
+
+[Illustration: Fig. 214.--The 50 Horse-Power Rotary Bayerischen Motoren
+Gesellschaft Engine, a German Adaptation of the Early Gnome Design.]
+
+A German adaptation of the Gnome design is shown at Fig. 214. This is
+known as the Bayerischen Motoren Gesellschaft engine and the type shown
+is an early design rated at 50 horse-power. The bore is 110 mm., the
+stroke is 120 mm., and it is designed to run at a speed of 1,200 R. P.
+M. It is somewhat similar in design to the early Gnome "valve-in-piston"
+design except that two valves are carried in the piston top instead of
+one. The valve operating arrangement is different also, as a single four
+point cam is used to operate the seven exhaust valves. It is driven by
+epicyclic gearing, the cam being driven by an internal gear machined
+integrally with it, the cam being turned at 7/8 times the engine speed.
+Another feature is the method of holding the cylinders on the
+crank-case. The cylinder is provided with a flange that registers with a
+corresponding member of the same diameter on the crank-case. A U
+section, split clamping ring is bolted in place as shown, this holding
+both flanges firmly together and keeping the cylinder firmly seated
+against the crank-case flange. The "monosoupape" type has also been
+copied and has received some application in Germany, but the most
+successful German airplanes are powered with six-cylinder vertical
+engines such as the Benz and Mercedes.
+
+
+THE LE RHONE MOTOR
+
+The Le Rhone motor is a radial revolving cylinder engine that has many
+of the principles which are incorporated in the Gnome but which are
+considered to be an improvement by many foreign aviators. Instead of
+having but one valve in the cylinder head, as the latest type
+"monosoupape" Gnome has, the Le Rhone has two valves, one for intake and
+one for exhaust in each cylinder. By an ingenious rocker arm and tappet
+rod arrangement it is possible to operate both valves with a single push
+rod. Inlet pipes communicate with the crank-case at one end and direct
+the fresh gas to the inlet valve cage at the other. Another peculiarity
+in the design is the method of holding the cylinders in place. Instead
+of having a vertically divided crank-case as the Gnome engine has and
+clamping both halves of the case around the cylinders, the crank-case of
+the Le Rhone engine is in the form of a cylinder having nine bosses
+provided with threaded openings into which the cylinders are screwed. A
+thread is provided at the base of each cylinder and when the cylinder
+has been screwed down the proper amount it is prevented from further
+rotation about its own axis by a substantial lock nut which screws down
+against the threaded boss on the crank-case. The external appearance of
+the Le Rhone type motor is clearly shown at Fig. 215, while the general
+features of construction are clearly outlined in the sectional views
+given at Figs. 216 and 217.
+
+[Illustration: Fig. 215--Nine-Cylinder Revolving Le Rhone Type Aviation
+Engine.]
+
+[Illustration: Fig. 216.--Part Sectional Views of Le Rhone Rotary
+Cylinder Engine, Showing Method of Cylinder Retention, Valve Operation
+and Novel Crank Disc Assembly.]
+
+[Illustration: Fig. 217.--Side Sectional View of Le Rhone Aviation
+Engine.]
+
+[Illustration: Fig. 218.--View Showing Le Rhone Valve Action and
+Connecting Rod Big End Arrangement.]
+
+The two main peculiarities of this motor are the method of valve
+actuation by two large cams and the distinctive crank-shaft and
+connecting rod big end construction. The connecting rods are provided
+with "feet" or shoes on the end which fit into grooves lined with
+bearing metal which are machined into crank discs revolving on ball
+bearings and which are held together so that the connecting rod big ends
+are sandwiched between them by clamping screws. This construction is a
+modification of that used on the Anzani six-cylinder radial engine.
+There are three grooves machined in each crank disc and three connecting
+rod big ends run in each pair of grooves. The details of this
+construction can be readily ascertained by reference to explanatory
+diagrams at Figs. 218 and 219, A. Three of the rods which work in the
+groove nearest the crank-pin are provided with short shoes as shown at
+Fig. 219, B. The short shoes are used on the rods employed in cylinders
+number 1, 4, and 7. The set of connecting rods that work in the central
+grooves are provided with medium-length shoes and actuate the pistons in
+cylinders numbers 3, 6, and 9. The three rods that work in the outside
+grooves have still longer shoes and are employed in cylinders numbers 2,
+5, and 8. The peculiar profile of the inlet and exhaust cam plates are
+shown at C, Fig. 219, while the construction of the wrist-pin, wrist-pin
+bushing and piston are clearly outlined at the sectional view at E. The
+method of valve actuation is clearly outlined at Fig. 220, which shows
+an end section through the cam case and also a partial side elevation
+showing one of the valve operating levers which is fulcrumed at a
+central point and which has a roller at one end bearing on one cam while
+the roller or cam follower at the other end bears on the other cam. The
+valve rocker arm actuating rod is, of course, operated by this simple
+lever and is attached to it in such a way that it can be pulled down to
+depress the inlet valve and pushed up to open the exhaust valve.
+
+[Illustration: Fig. 219.--Diagrams Showing Important Components of Le
+Rhone Motor.]
+
+[Illustration: Fig. 220.--How the Cams of the Le Rhone Motor Can Operate
+Two Valves with a Single Push Rod.]
+
+A carburetor of peculiar construction is employed in the Le Rhone
+engine, this being a very simple type as outlined at Fig. 221. It is
+attached to the threaded end of the hollow crank-shaft by a right and
+left coupling. The fuel is pumped to the spray nozzle, the opening in
+which is controlled by a fuel regulating needle having a long taper
+which is lifted out of the jet opening when the air-regulating slide is
+moved. The amount of fuel supplied the carburetor is controlled by a
+special needle valve fitting which combines a filter screen and which is
+shown at B. In regulating the speed of the Le Rhone engine, there are
+two possible means of controlling the mixture, one by altering the
+position of the air-regulating slide, which also works the metering
+needle in the jet, and the other by controlling the amount of fuel
+supplied to the spray nozzle through the special fitting provided for
+that purpose.
+
+[Illustration: Fig. 221.--The Le Rhone Carburetor at A and Fuel Supply
+Regulating Device at B.]
+
+In considering the action of this engine one can refer to Fig. 222. The
+crank O. M. is fixed, while the cylinders can turn about the crank-shaft
+center O and the piston turns around the crank-pin M, because of the
+eccentricity of the centers of rotation the piston will reciprocate in
+the cylinders. This distance is at its maximum when the cylinder is
+above O and at a minimum when it is above M, and the difference between
+these two positions is equal to the stroke, which is twice the distance
+of the crank-throw O, M. The explosion pressure resolves itself into the
+force F exerted along the line of the connecting rod A, M, and also into
+a force N, which tends to make the cylinders rotate around point O in
+the direction of the arrow. An odd number of cylinders acting on one
+crank-pin is desirable to secure equally spaced explosions, as the basic
+action is the same as the Gnome engine.
+
+[Illustration: Fig. 222.--Diagrams Showing Le Rhone Motor Action and
+Firing Order.]
+
+The magneto is driven by a gear having 36 teeth attached to crank-case
+which meshes with 16-tooth pinion on armature. The magneto turns at 2.25
+times crank-case speed. Two cams, one for inlet, one for exhaust, are
+mounted on a carrying member and act on nine rocker arms which are
+capable of giving a push-and-pull motion to the valve-actuating
+rocker-operating rods. A gear driven by the crank-case meshes with a
+larger member having internal teeth carried by the cam carrier. Each cam
+has five profiles and is mounted in staggered relation to the other.
+These give the nine fulcrumed levers the proper motion to open the inlet
+and exhaust valves at the proper time. The cams are driven at 45/50 or
+9/10 of the motor speed. The cylinder dimensions and timing follows; the
+weight can be approximated by figuring 3 pounds per horse-power.
+
+ 80 H.P. 105 M/M bore 4.20" bore.
+ 140 M/M stroke 5.60" stroke.
+
+ 110 H.P. 112 M/M bore 4.48" bore.
+ 170 M/M stroke 6.80" stroke.
+
+ Timing--Intake valve opening, lag 18 deg.} 18 deg.}
+ Intake valve closing, lag 35 deg.} 35 deg.}
+ Exhaust valve opening, lead 55 deg.} 110 H.P. 45 deg.} 80 H.P.
+ Exhaust valve closing, lag 5 deg.} 5 deg.}
+ Ignition time advance 26 deg.} 26 deg.}
+
+[Illustration: Fig. 223.--Diagram Showing Positions of Piston in Le
+Rhone Rotary Cylinder Motor.]
+
+
+THE RENAULT AIR-COOLED VEE ENGINE
+
+[Illustration: Fig. 224.--Diagrams Showing Valve Timing of Le Rhone
+Aviation Engine.]
+
+[Illustration: Fig. 225.--Diagrams Showing How Cylinder Cooling is
+Effected in Renault Vee Engines.]
+
+Air-cooled stationary engines are rarely used in airplanes, but the
+Renault Freres of France have for several years manufactured a complete
+series of such engines of the general design shown at Fig. 225, ranging
+from a low-powered one developed eight or nine years ago and rated at
+40 and 50 horse-power, to later eight-cylinder models rated at 70
+horse-power and a twelve-cylinder, or twin six, rated at 90 horse-power.
+The cylinders are of cast iron and are furnished with numerous cooling
+ribs which are cast integrally. The cylinder heads are separate
+castings and are attached to the cylinder as in early motorcycle engine
+practice, and serve to hold the cylinder in place on the aluminum alloy
+crank-case by a cruciform yoke and four long hold-down bolts (Fig. 226).
+The pistons are of cast steel and utilize piston rings of cast iron. The
+valves are situated on the inner side of the cylinder head, the
+arrangement being unconventional in that the exhaust valves are placed
+above the inlet. The inlet valves seat in an extension of the combustion
+head and are actuated by direct push rod and cam in the usual manner
+while an overhead gear in which rockers are operated by push rods is
+needed to actuate the exhaust valves. The valve action is clearly shown
+in Figs. 226 and 227. The air stream by which the cylinders are cooled
+is produced by a centrifugal or blower type fan of relatively large
+diameter which is mounted on the end of a crank-shaft and the air blast
+is delivered from this blower into an enclosed space between the
+cylinder from which it escapes only after passing over the cooling fins.
+In spite of the fact that considerable prejudice exists against
+air-cooling fixed cylinder engines, the Renault has given very good
+service in both England and France.
+
+[Illustration: Fig. 226.--End Sectional View of Renault Air-Cooled
+Aviation Engine.]
+
+[Illustration: Fig. 227.--Side Sectional View of Renault Twelve-Cylinder
+Air-Cooled Aviation Engine Crank-Case, Showing Use of Plain and Ball
+Bearings for Crank-Shaft Support.]
+
+As will be seen by the sectional view at Fig. 227, the steel crank-shaft
+is carried in a combination of plain bearings inside the crank-case and
+by ball bearings at the ends. Owing to air cooling, special precautions
+are taken with the lubrication system, though the lubrication is not
+forced or under high pressure. An oil pump of the gear-wheel type
+delivers oil from the sump at the bottom of the crank-case to a chamber
+above, from which the oil flows by gravity along suitable channels to
+the various main bearings. It flows from the bearings into hollow rings
+fastened to the crank-webs, and the oil thrown from the whirling
+connecting rod big ends bathes the internal parts in an oil mist. In the
+eight-cylinder designs ignition is effected by a magneto giving four
+sparks per revolution and is accordingly driven at engine speed. In the
+twelve-cylinder machine two magnetos of the ordinary revolving armature
+or two-spark type, each supplying six cylinders, are fitted as outlined
+at Fig. 228. The carburetor is a float feed form. Warm air is supplied
+for Winter and damp weather by air pipes surrounding the exhaust pipes.
+The normal speed of the Renault engine is 1,800 R. P. M., but as the
+propeller is mounted upon an extension of the cam-shaft the normal
+propeller speed is but half that of the engine, which makes it possible
+to use a propeller of large diameter and high efficiency. Owing to the
+air cooling, but low compression may be used, this being about 60 pounds
+per square inch, which, of course, lowers the mean effective pressure
+and makes the engine less efficient than water-cooled forms where it is
+possible to use compression pressure of 100 or more pounds per square
+inch. The 70 horse-power engine has cylinders with a bore of 3.78 inches
+and a stroke of 5.52 inches. Its weight is given as 396 pounds, when in
+running order, which figures 5.7 pounds per horse-power. The same
+cylinder size is used on the twelve-cylinder 100 horse-power and the
+stroke is the same. This engine in running order weighs 638 pounds,
+which figures approximately 6.4 pounds per B. H. P.
+
+[Illustration: Fig. 228.--End View of Renault Twelve-Cylinder Engine
+Crank-Case, Showing Magneto Mounting.]
+
+[Illustration: Fig. 229.--Diagram Outlining Renault Twelve-Cylinder
+Engine Ignition System.]
+
+
+SIMPLEX MODEL "A" HISPANO-SUIZA
+
+The Model A is of the water-cooled four-cycle Vee type, with eight
+cylinders, 4.7245 inch bore by 5.1182 inch stroke, piston displacement
+718 cubic inches. At sea-level it develops 150 horse-power at 1,450 R.
+P. M. It can be run successfully at much higher speeds, depending on
+propeller design and gearing, developing proportionately increased
+power. The weight, including carburetor, two magnetos, propeller hub,
+starting magneto and crank, but without radiator, water or oil or
+exhaust pipes, is 445 pounds. Average fuel consumption is .5 pound per
+horse-power hour and the oil consumption at 1,450 R. P. M. is three
+quarts per hour. The external appearance is shown at Fig. 230.
+
+Four cylinders are contained in each block, which is of built-up
+construction; the water jackets and valve ports are cast aluminum and
+the individual cylinders heat-treated steel forgings threaded into the
+bored holes of the aluminum castings. Each block after assembly is given
+a number of protective coats of enamel, both inside and out, baked on.
+Coats on the inside are applied under pressure. The pistons are aluminum
+castings, ribbed. Connecting rods are tubular, of the forked type. One
+rod bears directly on the crank-pin; the other rod has a bearing on the
+outside of the one first mentioned.
+
+The crank-shaft is of the five-bearing type, very short, stiff in
+design, bored for lightness and for the oiling system. The crank-shaft
+extension is tapered for the French standard propeller hub, which is
+keyed and locked to the shaft. This makes possible instant change of
+propellers. The case is in two halves divided on the center line of the
+crank-shaft, the bearings being fitted between the upper and lower
+sections. The lower half is deep, providing a large oil reservoir and
+stiffening the engine. The upper half is simple and provides magneto
+supports on extension ledges of the two main faces. The valves are of
+large diameter with hollow stems, working in cast iron bushings. They
+are directly operated by a single hollow cam-shaft located over the
+valves. The cam-shafts are driven from the crank-shaft by vertical
+shafts and bevel gears. The cam-shafts, cams and heads of the valve
+stems are all enclosed in oil-tight removable housings of cast aluminum.
+
+[Illustration: Fig. 230.--The Simplex Model A Hispano-Suiza Aviation
+Engine, a Very Successful Form.]
+
+Oiling is by a positive pressure system. The oil is taken through a
+filter and steel tubes cast in the case to main bearings, through
+crank-shaft to crank-pins. The fourth main bearing is also provided with
+an oil lead from the system and through tubes running up the end of each
+cylinder block, oil is provided for the cam-shafts, cams and bearings.
+The surplus oil escapes through the end of the cam-shaft where the
+driving gears are mounted, and with the oil that has gathered in the top
+casing, descends through the drive shaft and gears to the sump.
+
+Ignition is by two eight-cylinder magnetos firing two spark-plugs per
+cylinder. The magnetos are driven from each of the two vertical shafts
+by small bevel pinions meshing in bevel gears. The carburetor is mounted
+between the two cylinder blocks and feeds the two blocks through
+aluminum manifolds which are partly water-jacketed. The engine can be
+equipped with a geared hand crank-starting device.
+
+
+STURTEVANT MODEL 5A 140 HORSE-POWER ENGINE
+
+These motors are of the eight-cylinder "V" type, four-stroke cycle,
+water-cooled, having a bore of 4 inches and a stroke of 5-1/2 inches,
+equivalent to 102 mm. x 140 mm. The normal operating speed of the
+crank-shaft is 2,000 R. P. M. The propeller shaft is driven through
+reducing gears which can be furnished in different gear ratios. The
+standard ratio is 5:3, allowing a propeller speed of 1,200 R. P. M.
+
+The construction of the motor is such as to permit of the application of
+a direct drive. The change from the direct drive to gear drive, or vice
+versa, can be accomplished in approximately one hour.
+
+The cylinders are cast in pairs from an aluminum alloy and are provided
+with steel sleeves, carefully fitted into each cylinder. A perfect
+contact is secured between cylinder and sleeve; at the same time a
+sleeve can be replaced without injury to the cylinder proper. No
+difficulties due to expansion occur on account of the rapid transmission
+of heat and the fact that the sleeve is always at higher temperature
+than the cylinder. A moulded copper asbestos gasket is placed between
+the cylinder and the head, permitting the cooling water to circulate
+freely and at the same time insuring a tight joint. The cylinder heads
+are cast in pairs from an aluminum alloy and contain ample water
+passages for circulation of cooling water over the entire head. Trouble
+due to hot valves is thereby eliminated, a most important consideration
+in the operation of an aeroplane motor. The water jacket of the head
+corresponds to the water jacket of the cylinders and large openings in
+both allow the unobstructed circulation of the cooling water. The
+cylinder heads and cylinders are both held to the base by six long
+bolts. The valves are located in the cylinder heads and are mechanically
+operated. The valves and valve springs are especially accessible and of
+such size as to permit high volumetric efficiency. The valves are
+constructed of hardened tungsten steel, the heads and stems being made
+from one piece. The valve rocker arms located on the top of the cylinder
+are provided with adjusting screws. A check nut enables the adjusting
+screw to be securely locked in position, once the correct clearance has
+been determined. The rocker arm bearings are adequately lubricated by a
+compression grease cup. Cam-rollers are interposed between the cams and
+the push rods in order to reduce the side thrust on the push rods.
+
+A system of double springs is employed which greatly reduces the stress
+on each spring and insures utmost reliability. A spring of extremely
+large diameter returns the valve; a second spring located at the
+cylinder base handles the push rod linkage. These springs, which operate
+under low stress, are made from the best of steel and are given a
+special double heat treatment. The pistons are made from a special
+aluminum alloy; are deeply ribbed in the head for cooling and strength
+and provided with two piston rings. These pistons are exceedingly light
+weight in order to minimize vibration and prevent wear on the bearings.
+The piston pin is made of chrome nickel steel, bored hollow and
+hardened. It is allowed to turn, both in piston and connecting rod. The
+piston rings are of special design, developed after years of
+experimenting in aeronautical engines.
+
+The connecting rods are of "H" section, machined all over from forgings
+of a special air-hardening chrome nickel steel which, after being heat
+treated has a tensile strength of 280,000 pounds per square inch. They
+are consequently very strong and yet unusually light, and being machined
+all over are of absolutely uniform section, which gives as nearly
+perfect balance as can be obtained. The big ends are lined with white
+metal and the small ends are bushed with phosphor bronze. The connecting
+rods are all alike and take their bearings side by side on the
+crank-pin, the cylinders being offset to permit of this arrangement. The
+crank-shaft is machined from the highest grade chrome nickel steel, heat
+treated in order to obtain the best properties of this material. It is
+2-1/4 inches in diameter (57 mm.) and bored hollow throughout, insuring
+maximum strength with minimum weight. It is carried in three large,
+bronze-backed white metal bearings. A new method of producing these
+bearings insures a perfect bond between the two metals and eliminates
+breakage.
+
+The base is cast from an aluminum alloy. Great strength and rigidity is
+combined with light weight. The sides extend considerably below the
+center line of the crank-shaft, providing an extremely deep section. At
+all highly stressed points, deep ribs are provided to distribute the
+load evenly and eliminate bending. The lower half of the base is of cast
+aluminum alloy of extreme lightness. This collects the lubricating oil
+and acts as a small reservoir for same. An oil-filtering screen of large
+area covers the entire surface of the sump. The propeller shaft is
+carried on two large annular ball bearings driven from the crank-shaft
+by hardened chrome nickel steel spur gears. These gears are contained
+within an oil-tight casing integral with the base on the opposite end
+from the timing gears. A ball-thrust bearing is provided on the
+propeller shaft to take the thrust of a propeller or tractor, as the
+case may be. In case of the direct drive a stub shaft is fastened direct
+to the crank-shaft and is fitted with a double thrust bearing.
+
+The cam-shaft is contained within the upper half of the base between the
+two groups of cylinders, and is supported in six bronze bearings. It is
+bored hollow throughout and the cams are formed integral with the shaft
+and ground to the proper shape and finish. An important development in
+the shape of cams has resulted in a maintained increase of power at high
+speeds. The gears operating the cam-shaft, magneto, oil and water pumps
+are contained within an oil-tight casing and operate in a bath of oil.
+
+Lubrication is of the complete forced circulating system, the oil being
+supplied to every bearing under high pressure by a rotary pump of large
+capacity. This is operated by gears from the crank-shaft. The oil
+passages from the pump to the main bearings are cast integral with the
+base, the hollow crank-shaft forming a passage through the connecting
+rod bearings and the hollow cam-shaft distributing the oil to the
+cam-shaft bearings. The entire surface of the lower half of the base is
+covered with a fine mesh screen through which the oil passes before
+reaching the pump. Approximately one gallon of oil is contained within
+the base and this is continually circulated through an external tank by
+a secondary pump operated by an eccentric on the cam-shaft. This also
+draws fresh oil from the external tank which can be made of any desired
+capacity.
+
+
+SPECIFICATIONS--MODEL 5A TYPE 8
+
+ Horse-power rating, 140 at 2,000 R. P. M.
+ Bore, 4 inches = 102 mm.
+ Stroke, 5-1/2 inches = 140 mm.
+ Number of cylinders, 8.
+ Arrangement of cylinders, "V."
+ Cooling, water. Circulation by centrifugal pump.
+ Cycle, four stroke.
+ Ignition (double), 2 Bosch or Splitdorf magnetos.
+ Carburetor, Zenith duplex. Water jacket manifold.
+ Oiling system, complete forced. Circulating gear pump.
+ Normal crank-shaft speed, 2,000 R. P. M.
+ Propeller shaft, 3/5 crank-shaft speed at normal, 1,200 R. P. M.
+ Stated power at 30" barometer, 140 B. H. P.
+ Stated weight with all accessories but without water, gasoline or oil,
+ 514 pounds = 234 kilos.
+ Weight per B. H. P., 3.7 pounds = 1.68 kilos.
+ Stated weight with all accessories with water, 550 pounds = 250 kilos.
+ Weight per B. H. P. with water, 3.95 pounds = 1.79 kilos.
+
+
+THE CURTISS AVIATION MOTORS
+
+The Curtiss OX motor has eight cylinders, 4-inch bore, 5-inch stroke,
+delivers 90 horse-power at 1,400 turns, and the weight turns out at 4.17
+pounds per horse-power. This motor has cast iron cylinders with monel
+metal jackets, overhead inclined valves operated by means of two rocker
+arms, push-and-pull rods from the central cam-shaft located in the
+crank-case. The cam and push rod design is extremely ingenious and the
+whole valve construction turns out very light. This motor is an
+evolution from the early Curtiss type motor which was used by Glenn
+Curtiss when he won the Gordon Bennett Cup at Rheims. A slightly larger
+edition of this type motor is the OXX-5, as shown at Figs. 231 and 232,
+which has cylinders 4-1/4 inches by 5 inches, delivers 100 horse-power
+at 1,400 turns and has the same fuel and oil consumption as the OX type
+motor, namely, .60 pound of fuel per brake horse-power hour and .03
+pound of lubricating oil per brake horse-power hour.
+
+[Illustration: Fig. 231.--The Curtiss OXX-5 Aviation Engine is an
+Eight-Cylinder Type Largely Used on Training Machines.]
+
+The Curtiss Company have developed in the last two years a larger-sized
+motor now known as the V-2, which was originally rated at 160
+horse-power and which has since been refined and improved so that the
+motor gives 220 horse-power at 1,400 turns, with a fuel consumption of
+52/100 of a pound per brake horse-power hour and an oil consumption of
+.02 of a pound per brake horse-power hour. This larger motor has a
+weight of 3.45 pounds per horse-power and is now said to be giving very
+satisfactory service. The V-2 motor has drawn steel cylinders, with a
+bore of 5 inches and a stroke of 7 inches, with a steel water jacket top
+and a monel metal cylindrical jacket, both of which are brazed on to the
+cylinder barrel itself. Both these motors use side by side connecting
+rods and fully forced lubrication. The cam-shafts act as a gallery from
+which the oil is distributed to the cam-shaft bearings, the main
+crank-shaft bearings, and the gearing. Here again we find extremely
+short rods, which, as before mentioned, enables the height and the
+consequent weight of construction to be very much reduced. For ordinary
+flying at altitudes of 5,000 to 6,000 feet, the motors are sent out with
+an aluminum liner, bolted between the cylinder and the crank-case in
+order to give a compression ratio which does not result in pre-ignition
+at a low altitude. For high flying, however, these aluminum liners are
+taken out and the compression volume is decreased to about 18.6 per
+cent. of the total volume.
+
+[Illustration: Fig. 232.--Top and Bottom Views of the Curtiss OXX-5 100
+Horse-Power Aviation Engine.]
+
+The Curtiss Aeroplane Company announces that it has recently built, and
+is offering, a twelve-cylinder 5" x 7" motor, which was designed for
+aeronautical uses primarily. This engine is rated at 250 horse-power,
+but it is claimed to develop 300 at 1,400 R. P. M. Weights--Motor, 1,125
+pounds; radiator, 120 pounds; cooling water, 100 pounds; propeller, 95
+pounds.
+
+Gasoline Consumption per Horse-power Hour, 6/10 pounds.
+
+Oil Consumption per Hour at Maximum Speed--2 pints.
+
+Installation Dimensions--Overall length, 84-5/8 inches; overall width,
+34-1/8 inches; overall depth, 40 inches; width at bed, 30-1/2 inches;
+height from bed, 21-1/8 inches; depth from bed, 18-1/2 inches.
+
+
+THOMAS-MORSE MODEL 88 ENGINE
+
+The Thomas-Morse Aircraft Corporation of Ithaca, N. Y., has produced a
+new engine, Model 88, bearing a close resemblance to the earlier model.
+The main features of that model have been retained; in fact, many parts
+are interchangeable in the two engines. Supported by the great
+development in the wide use of aluminum, the Thomas engineers have
+adopted this material for cylinder construction, which adoption forms
+the main departure from previous accepted design.
+
+The marked tendency to-day toward a higher speed of rotation has been
+conclusively justified, in the opinion of the Thomas engineers, by the
+continued reliable performance of engines with crank-shafts operating at
+speeds near 2,000 revolutions per minute, driving the propeller through
+suitable gearing at the most efficient speed. High speed demands that
+the closest attention be paid to the design of reciprocating and
+rotating parts and their adjacent units. Steel of the highest
+obtainable tensile strength must be used for connecting rods and piston
+pins, that they may be light and yet retain a sufficient factor of
+safety. Piston design is likewise subjected to the same strict scrutiny.
+At the present day, aluminum alloy pistons operate so satisfactorily
+that they may be said to have come to stay.
+
+The statement often made in the past, that the gearing down of an engine
+costs more in the weight of reduction gears and propeller shaft than is
+warranted by the increase in horse-power, is seldom heard to-day.
+
+The mean effective pressure remaining the same, the brake horse-power of
+any engine increases as the speed. That is, an engine delivering 100
+brake horse-power at 1,500 revolutions per minute will show 133 brake
+horse-power at 2,000 revolutions per minute, an increase of 33 brake
+horse-power. To utilize this increase in horse-power, a matter of some
+fifteen pounds must be spent in gearing and another fifteen perhaps on
+larger valves, bearings, etc. Two per cent. may be assumed lost in the
+gears. In other words, the increase in horse-power due to increasing the
+speed has been attained at the expense of about one pound per brake
+horse-power.
+
+The advantages of the eight-cylinder engine over the six and twelve,
+briefly stated, are: lower weight per horse-power, shorter length,
+simpler and stiffer crank-shaft, cam-shaft and crank-case, and simpler
+and more direct manifold arrangement. As to torque, the eight is
+superior to the six, and yet in practice not enough inferior to the
+twelve to warrant the addition of four more cylinders. It must, however,
+be recognized that the eight is subject to the action of inherent
+unbalanced inertia couples, which set up horizontal vibrations,
+impossible of total elimination. These vibrations are functions of the
+reciprocating weights, which, as already mentioned, are cut down to the
+minimum. Vibrations due to the elasticity of crank-case, crank-shaft,
+etc., can be and are reduced in the Thomas engine to minor quantities by
+ample webbing of the crank-case and judicious use of metal elsewhere.
+All things considered, there is actually so little difference to be
+discerned between the balance of a properly designed eight-cylinder
+engine and that of a six or twelve as to make a discussion of the pros
+and cons more one of theory than of practice.
+
+The main criticisms of the L head cylinder engine are that it is less
+efficient and heavier. This is granted, as it relates to cylinders
+alone. More thorough investigation, however, based on the main
+desideratum, weight-power ratio, leads us to other conclusions,
+particularly with reference to high speed engines. The valve gear must
+not be forgotten. A cylinder cannot be taken completely away from its
+component parts and judged, as to its weight value, by itself alone. A
+part away from the whole becomes an item unimportant in comparison with
+the whole. The valve gear of a high speed engine is a too often
+overlooked feature. The stamp of approval has been made by high speed
+automobile practice upon the overhead cam-shaft drive, with valves in
+the cylinder head operated direct from the cam-shaft or by means of
+valve lifters or short rockers.
+
+The overhead cam-shaft mechanism applied to an eight-cylinder engine
+calls for two separate cam-shafts carried above and supported by the
+cylinders in an oil-tight housing, and driven by a series of spur gears
+or bevels from the crank-shaft. It is patent that this valve gearing is
+heavy and complicated in comparison with the simple moving valve units
+of the L head engine, which are operated from one single cam-shaft,
+housed rigidly in the crank-case. The inherently lower volumetric
+efficiency of the L head engine is largely overcome by the use of a
+properly designed head, large valves and ample gas passages. Again, the
+customary use of a dual ignition system gives to the L head a relatively
+better opportunity for the advantageous placing of spark-plugs, in order
+that better flame propagation and complete combustion may be secured.
+
+[Illustration: Fig. 233.--End View of Thomas-Morse 150 Horse-Power
+Aluminum Cylinder Aviation Motor Having Detachable Cylinder Heads.]
+
+The Thomas Model 88 engine is 4-1/8 inch bore and 5-1/2 inch stroke. The
+cylinders and cylinder heads are of aluminum, and as steel liners are
+used in the cylinders the pistons are also made of aluminum. This engine
+is actually lighter than the earlier model of less power. It weighs but
+525 pounds, with self-starter. The general features of design can be
+readily ascertained by study of the illustrations: Fig. 233, which shows
+an end view; Fig. 234, which is a side view, and Fig. 235, which
+outlines the reduction gear-case and the propeller shaft supporting
+bearings.
+
+[Illustration: Fig. 234.--Side View of Thomas-Morse High Speed 150
+Horse-Power Aviation Motor with Geared Down Propeller Drive.]
+
+
+SIXTEEN-VALVE DUESENBERG ENGINE
+
+[Illustration: Fig. 235.--The Reduction Gear-Case of Thomas-Morse 150
+Horse-Power Aviation Motor, Showing Ball Bearing and Propeller Drive
+Shaft Gear.]
+
+This engine is a four-cylinder, 4-3/4" x 7", 125 horse-power at 2,100 R.
+P. M. of the crank-shaft and 1,210 R. P. M. of the propeller. Motors are
+sold on above rating; actual power tests prove this motor capable of
+developing 140 horse-power at 2,100 R. P. M. of the motor. The exact
+weight with magneto, carburetor, gear reduction and propeller hub, as
+illustrated, 509 pounds; without gear reduction, 436 pounds. This motor
+has been produced as a power plant weighing 3.5 pounds per horse-power,
+yet nothing has been sacrificed in rigidity and strength. At its normal
+speed it develops 1 horse-power for every 3.5 cubic inches piston
+displacement. Cylinders are semi-steel, with aluminum plates enclosing
+water jackets. Pistons specially ribbed and made of Magnalite aluminum
+compound. Piston rings are special Duesenberg design, being three-piece
+rings. Valves are tungsten steel, 1-15/16" inlets and 2" exhausts, two
+of each to each cylinder. Arranged horizontally in the head, allowing
+very thorough water-jacketing. Inlet valves in cages. Exhaust valves,
+seating directly in the cylinder head, are removable through the inlet
+valve holes. Valve stems lubricated by splash in the valve action
+covers. Valve rocker arms forged with cap screw and nut at upper end to
+adjust clearance. Entirely enclosed by aluminum housing, as is entire
+valve mechanism. Connecting rods are tubular, chrome nickel steel, light
+and strong. Crank-shaft is one-piece forging, hollow bored, 2-1/2-inch
+diameter at main bearings. Connecting rod bearings, 2-1/4-inch diameter,
+3 inches long. Front main bearing, 3-1/2 inches long; intermediate main
+bearing, 3-1/2 inches long; rear main bearing, 4 inches long. Crank-case
+of aluminum, barrel type, oil pan on bottom removable. Hand hole plates
+on both sides. Strongly webbed.
+
+The oiling system of this sixteen-valve Duesenberg motor is one of its
+vital features. An oil pump located in the base and submerged in oil
+forces oil through cored passages to the three main bearings, then
+through tubes under each connecting rod into which the rod dips. The oil
+is thrown off from these and lubricates every part of the motor. This
+constitutes the main oiling system; it is supplemented by a splash
+system, there being a trough under each connecting rod into which the
+rod slips. The oil is returned to the main supply sump by gravity, where
+it is strained and re-used. Either system is in itself sufficient to
+operate the motor. A pressure gauge is mounted for observation on a
+convenient part of the system. A pressure of approximately 25 pounds is
+maintained by the pressure system, which insures efficient lubrication
+at all speeds of the motor. The troughs under the connecting rods are so
+constructed that no matter what the angle of flight may be, oil is
+retained in each individual trough so that each connecting rod can dip
+up its supply of oil at each revolution.
+
+
+AEROMARINE SIX-CYLINDER VERTICAL MOTOR
+
+[Illustration: Fig. 236.--The Six-Cylinder Aeromarine Engine.]
+
+These motors are four-stroke cycle, six-cylinder vertical type, with
+cylinder 4-5/16" bore by 5-1/8" stroke. The general appearance of this
+motor is shown in illustration at Fig. 236. This engine is rated at
+85-90 horse-power. All reciprocating and revolving parts of this motor
+are made of the highest grades of steel obtainable as are the studs,
+nuts and bolts. The upper and lower parts of crank-case are made of
+composition aluminum casting. Lower crank-case is made of high grade
+aluminum composition casting and is bolted directly to the upper half.
+The oil reservoir in this lower half casting provides sufficient oil
+capacity for five hours' continuous running at full power. Increased
+capacity can be provided if needed to meet greater endurance
+requirements. Oil is forced under pressure to all bearings by means of
+high-pressured duplex-geared pumps. One side of this pump delivers oil
+under pressure to all the bearings, while the other side draws the oil
+from the splash case and delivers it to the main sump. The oil reservoir
+is entirely separate from the crank-case chamber. Under no circumstances
+will oil flood the cylinder, and the oiling system is not affected in
+any way by any angle of flight or position of motor. An oil pressure
+gauge is placed on instrument board of machine, which gives at all
+times the pressure in oil system, and a sight glass at lower half of
+case indicates the amount of oil contained. The oil pump is external on
+magneto end of motor, and is very accessible. An external oil strainer
+is provided, which is removable in a few minutes' time without the loss
+of any oil. All oil from reservoir to the motor passes through this
+strainer. Pressure gauge feed is also attached and can be piped to any
+part of machine desired.
+
+The cylinders are made of high-grade castings and are machined and
+ground accurately to size. Cylinders are bolted to crank-case with
+chrome nickel steel studs and nuts which securely lock cylinder to upper
+half of crank-case. The main retaining cylinder studs go through
+crank-case and support crank-shaft bearings so that crank-shaft and
+cylinders are tied together as one unit. Water jackets are of copper,
+1/16" thick, electrically deposited. This makes a non-corrosive metal.
+Cooling is furnished by a centrifugal pump, which delivers 25 gallons
+per minute at 1,400 R. P. M. Pistons are made cast iron, accurately
+machined and ground to exact dimensions, which are carefully balanced.
+Piston rings are semi-steel rings of Aeromarine special design.
+
+Connecting rods are of chrome nickel steel, H-section. Crank-shaft is
+made of chrome nickel steel, machined all over, and cut from solid
+billet, and is accurately balanced through the medium of balance weights
+being forged integral with crank. It is drilled for lightness and
+plugged for force feed lubrication. There are seven main bearings to
+crank-shaft. All bearings are of high-grade babbitt, die cast, and are
+interchangeable and easily replaced. The main bearings of the
+crank-shaft are provided with a single groove to take oil under pressure
+from pressure tube which is cast integral with case. Connecting rod
+bearings are of the same type. The gudgeon pin is hardened, ground and
+secured in connecting rod, and is allowed to work in piston. Cam-shaft
+is of steel, with cams forged integral, drilled for lightness and
+forced-feed lubrication, and is case-hardened. The bearings of
+cam-shaft are of bronze. Magneto, two high-tension Bosch D. U. 6. The
+intake manifold for carburetors are aluminum castings and are so
+designed that each carburetor feeds three cylinders, thereby insuring
+easy flow of vapor at all speeds. Weight, 420 pounds.
+
+[Illustration: Fig. 237.--The Wisconsin Aviation Engine, at Top, as
+Viewed from Carburetor Side. Below, the Exhaust Side.]
+
+
+WISCONSIN AVIATION ENGINES
+
+[Illustration: Fig. 238.--Dimensioned End Elevation of Wisconsin Six
+Motor.]
+
+The new six-cylinder Wisconsin aviation engines, one of which is shown
+at Fig. 237, are of the vertical type, with cylinders in pairs and
+valves in the head. Dimensioned drawings of the six-cylinder vertical
+type are given at Figs. 238 and 239. The cylinders are made of aluminum
+alloy castings, are bored and machined and then fitted with hardened
+steel sleeves about 1/16 inch in thickness. After these sleeves have
+been shrunk into the cylinders, they are finished by grinding in place.
+Gray iron valve seats are cast into the cylinders. The valve seats and
+cylinders, as well as the valve ports, are entirely surrounded by water
+jackets. The valves set in the heads at an angle of 25 deg. from the
+vertical, are made of tungsten steel and are provided with double
+springs, the outer or main spring and the inner or auxiliary spring,
+which is used as a precautionary measure to prevent a valve falling into
+the cylinder in remote case of a main spring breaking. The cam-shaft is
+made of one solid forging, case-hardened. It is carried in an aluminum
+housing bolted to the top of the cylinders. This housing is split
+horizontally, the upper half carrying the chrome vanadium steel rocker
+levers. The lower half has an oil return trough cast integral, into
+which the excess oil overflows and then drains back to the crank-case.
+Small inspection plates are fitted over the cams and inner ends of the
+cam rocker levers. The cam-shaft runs in bronze bearings and the drive
+is through vertical shaft and bevel gears.
+
+[Illustration: Fig. 239.--Dimensioned Side Elevation of Wisconsin Six
+Motor.]
+
+The crank-case is made of aluminum, the upper half carrying the
+bearings for the crank-shaft. The lower half carries the oil sump in
+which all of the oil except that circulating through the system at the
+time is carried. The crank-shaft is made of chrome vanadium steel of an
+elastic limit of 115,000 pounds. The crank-pins and ends of the shaft
+are drilled for lightness and the cheeks are also drilled for oil
+circulation. The crank-shaft runs in bronze-backed, Fahrig metal-lined
+bearings, four in number. A double thrust bearing is also provided, so
+that the motor may be used either in a tractor or pusher type of
+machine. Outside of the thrust bearing an annular ball bearing is used
+to take the radial load of the propeller. The propeller is mounted on a
+taper. At the opposite end of the shaft a bevel gear is fitted which
+drives the cam-shaft, through a vertical shaft, and also drives the
+water and oil pumps and magnetos. All gears are made of chrome vanadium
+steel, heat-treated.
+
+The connecting rods are tubular and machined from chrome vanadium steel
+forgings. Oil tubes are fitted to the rods which carry the oil up to the
+wrist-pins and pistons. The rods complete with bushings weigh 5-1/2
+pounds each. The pistons are made of aluminum alloy and are very light
+and strong, weighing only 2 pounds 2 ounces each. Two leak-proof rings
+are fitted to each piston. The wrist-pins are hollow, of hardened steel,
+and are free to turn either in the piston or the rod. A bronze bushing
+is fitted in the upper end of the rod, but no bushing is fitted in the
+pistons, the hardened steel wrist-pins making an excellent bearing in
+the aluminum alloy.
+
+[Illustration: Fig. 240.--Power, Torque and Efficiency Curves of
+Wisconsin Aviation Motor.]
+
+The water circulation is by centrifugal pump, which is mounted at the
+lower end of the vertical shaft. The water is pumped through brass pipes
+to the lower end of the cylinder water jackets and leaves the upper end
+of the jackets just above the exhaust valves. The lubricating system is
+one of the main features of the engines, being designed to work with the
+motor at any angle. The oil is carried in the sump, from where it is
+taken by the oil circulating pump through a strainer and forced through
+a header, extending the full length of the crank-case, and distributed
+to the main bearings. From the main bearings it is forced through the
+hollow crank-shaft to the connecting rod big ends and then through
+tubes on the rods to wrist-pins and pistons. Another lead takes oil from
+the main header to the cam-shaft bearings. The oil forced out of the
+ends of the cam-shaft bearings fills pockets under the cams and in the
+cam rocker levers. The excess flows back through pipes and through the
+train of gears to the crank-case. A strainer is fitted at each end of
+the crank-case, through which the oil is drawn by separate pumps and
+returned to the sump. Either one of these pumps is large enough to take
+care of all of the return oil, so that the operation is perfect whether
+the motor is inclined up or down. No splash is used in the crank-case,
+the system being a full force feed. An oil level indicator is provided,
+showing the amount of oil in the sump at all times. The oil pressure in
+these motors is carried at ten pounds, a relief valve being fitted to
+hold the pressure constant.
+
+[Illustration: Fig. 241.--Timing Diagram, Wisconsin Aviation Engine.]
+
+Ignition is by two Bosch magnetos, each on a separate set of plugs fired
+simultaneously on opposite sides of the cylinders. Should one magneto
+fail, the other would still run the engine at only a slight loss in
+power. The Zenith double carburetor is used, three cylinders being
+supplied by each carburetor. This insures a higher volumetric
+efficiency, which means more power, as there is no overlapping of inlet
+valves whatever by this arrangement. All parts of these motors are very
+accessible. The water and oil pumps, carburetors, magnetos, oil strainer
+or other parts can be removed without disturbing other parts. The lower
+crank-case can be removed for inspection or adjustment of bearings, as
+the crank-shaft and bearing caps are carried by the upper half. The
+motor supporting lugs are also part of the upper crank-case.
+
+The six-cylinder motor, without carburetors or magnetos, weighs 547
+pounds. With carburetor and magnetos, the weight is 600 pounds. The
+weight of cooling water in the motor is 38 pounds. The sump will carry 4
+gallons of oil, or about 28 pounds. A radiator can be furnished suitable
+for the motor, weighing 50 pounds. This radiator will hold 3 gallons of
+water or about 25 pounds. The motor will drive a two-blade, 8 feet
+diameter by 6.25 feet pitch Paragon propeller 1400 revolutions per
+minute, developing 148 horse-power. The weight of this propeller is 42
+pounds. This makes a total weight of motor, complete with propeller,
+radiator filled with water, but without lubricating oil, 755 pounds, or
+about 5.1 pounds per horse-power for complete power plant. The fuel
+consumption is .5 pound per horse-power per hour. The lubricating oil
+consumption is .0175 pound per horse-power per hour, or a total of 2.6
+pounds per hour at 1400 revolutions per minute. This would make the
+weight of fuel and oil, per hour's run at full power at 1400 revolutions
+per minute, 76.6 pounds.
+
+
+PRINCIPAL DIMENSIONS
+
+Following are the principal dimensions of the six-cylinder motor:
+
+ Bore 5 inches.
+ Stroke 6-1/2 inches.
+ Crank-shaft diameter throughout 2 inches.
+ Length of crank-pin and main bearings 3-1/2 inches.
+ Diameter of valves 3 inches (2-3/4 inches clear).
+ Lift of valves 1/2 inch.
+ Volume of compression space 22 per cent. of total.
+ Diameter of wrist-pins 1-3/16 inches.
+ Firing order 1-4-2-6-3-5.
+
+The horse-power developed at 1200 revolutions per minute is 130, at 1300
+revolutions per minute 140, at 1400 revolutions per minute 148. 1400 is
+the maximum speed at which it is recommended to run these motors.
+
+
+TWELVE-CYLINDER ENGINE
+
+A twelve-cylinder V-type engine illustrated, is also being built by this
+company, similar in dimensions of cylinders to the six. The principal
+differences being in the drive to cam-shaft, which is through spur gears
+instead of bevel. A hinged type of connecting rod is used which does not
+increase the length of the motor and, at the same time, this
+construction provides for ample bearings. A double centrifugal water
+pump is provided for this motor, so as to distribute the water uniformly
+to both sets of cylinders. Four magnetos are used, two for each set of
+six cylinders. The magnetos are very accessibly located on a bracket on
+the spur gear cover. The carburetors are located on the outside of the
+motors, where they are very accessible, while the exhaust is in the
+center of the valley. The crank-shaft on the twelve is 2-1/2 inches in
+diameter and the shaft is bored to reduce weight. Dimensioned drawings
+of the twelve-cylinder engine are given at Figs. 242 and 243 and should
+prove useful for purposes of comparison with other motors.
+
+
+HALL-SCOTT AVIATION ENGINES
+
+The following specifications of the Hall-Scott "Big Four" engines apply
+just as well to the six-cylinder vertical types which are practically
+the same in construction except for the structural changes necessary to
+accommodate the two extra cylinders. Cylinders are cast separately from
+a special mixture of semi-steel, having cylinder head with valve seats
+integral. Special attention has been given to the design of the water
+jacket around the valves and head, there being two inches of water space
+above same. The cylinder is annealed, rough machined, then the inner
+cylinder wall and valve seats ground to mirror finish. This adds to the
+durability of the cylinder, and diminishes a great deal of the excess
+friction.
+
+[Illustration: Fig. 242.--Dimensioned End View of Wisconsin
+Twelve-Cylinder Airplane Motor.]
+
+Great care is taken in the casting and machining of these cylinders, to
+have the bore and walls concentric with each other. Small ribs are cast
+between outer and inner walls to assist cooling as well as to transfer
+stresses direct from the explosion to hold-down bolts which run from
+steel main bearing caps to top of cylinders. The cylinders are machined
+upon the sides so that when assembled on the crank-case with grooved
+hold-down washers tightened, they form a solid block, greatly assisting
+the rigidity of crank-case.
+
+[Illustration: Fig. 243.--Dimensioned Side Elevation of Wisconsin
+Twelve-Cylinder Airplane Motor.]
+
+The connecting rods are very light, being of the I beam type, milled
+from a solid Chrome nickel die forging. The caps are held on by two
+1/2"-20 thread Chrome nickel through bolts. The rods are first roughed
+out, then annealed. Holes are drilled, after which the rods are hardened
+and holes ground parallel with each other. The piston end is fitted with
+a gun metal bushing, while the crank-pin end carries two bronze serrated
+shells, which are tinned and babbitted hot, being broached to harden the
+babbitt. Between the cap and rod proper are placed laminated shims for
+adjustment. Crank-cases are cast of the best aluminum alloy, hand
+scraped and sand blasted inside and out. The lower oil case can be
+removed without breaking any connections, so that the connecting rods
+and other working parts can readily be inspected. An extremely large
+strainer and dirt trap is located in the center and lowest point of the
+case, which is easily removed from the outside without disturbing the
+oil pump or any working parts. A Zenith carburetor is provided.
+Automatic valves and springs are absent, making the adjustment simple
+and efficient. This carburetor is not affected by altitude to any
+appreciable extent. A Hall-Scott device, covered by U. S. Patent No.
+1,078,919, allows the oil to be taken direct from the crank-case and run
+around the carburetor manifold, which assists carburetion as well as
+reduces crank-case heat. Two waterproof four-cylinder Splitdorf "Dixie"
+magnetos are provided. Both magneto interruptors are connected to a rock
+shaft integral with the motor, making outside connections unnecessary.
+It is worthy of note that with this independent double magneto system,
+one complete magneto can become inoperative, and still the motor will
+run and continue to give good power.
+
+The pistons as provided in the A-7 engines are cast from a mixture of
+steel and gray iron. These are extremely light, yet provided with six
+deep ribs under the arch head, greatly aiding the cooling of the piston
+as well as strengthening it. The piston pin bosses are located very low
+in order to keep the heat from the piston head away from the upper end
+of the connecting rod, as well as to arrange them at the point where the
+piston fits the cylinder best. Three 1/4" rings are carried. The pistons
+as provided in the A-7a engines are cast from aluminum alloy. Four 1/4"
+rings are carried. In both piston types a large diameter, heat treated,
+Chrome nickel steel wrist-pin is provided, assembled in such a way as to
+assist the circular rib between the wrist-pin bosses to keep the piston
+from being distorted from the explosions.
+
+The oiling system is known as the high pressure type, oil being forced
+to the under side of the main bearings with from 5 to 30 points
+pressure. This system is not affected by extreme angles obtained in
+flying, or whether the motor is used for push or pull machines. A large
+gear pump is located in the lowest point of the oil sump, and being
+submerged at all times with oil, does away with troublesome stuffing
+boxes and check valves. The oil is first drawn from the strainer in oil
+sump to the long jacket around the intake manifold, then forced to the
+main distributor pipe in crank-case, which leads to all main bearings. A
+bi-pass, located at one end of the distributor pipe, can be regulated to
+provide any pressure required, the surplus oil being returned to the
+case. A special feature of this system is the dirt, water and sediment
+trap, located at the bottom of the oil sump. This can be removed without
+disturbing or dismantling the oil pump or any oil pipes. A small oil
+pressure gauge is provided, which can be run to the aviator's instrument
+board. This registers the oil pressure, and also determines its
+circulation.
+
+The cooling of this motor is accomplished by the oil as well as the
+water, this being covered by patent No. 1,078,919. This is accomplished
+by circulating the oil around a long intake manifold jacket; the
+carburetion of gasoline cools this regardless of weather conditions.
+Crank-case heat is therefore kept at a minimum. The uniform temperature
+of the cylinders is maintained by the use of ingenious internal outlet
+pipes, running through the head of each of the six-cylinders, rubber
+hose connections being used so that any one of the cylinders may be
+removed without disturbing the others. Slots are cut in these pipes so
+that cooler water is drawn directly around the exhaust valves. Extra
+large water jackets are provided upon the cylinders, two inches of water
+space is left above the valves and cylinder head. The water is
+circulated by a large centrifugal pump insuring ample circulation at all
+speeds.
+
+The crank-shaft is of the five bearing type, being machined from a
+special heat treated drop forging of the highest grade nickel steel. The
+forging is first drilled, then roughed out. After this the shaft is
+straightened, turned down to a grinding size, then ground accurately to
+size. The bearing surfaces are of extremely large size, over-size,
+considering general practice in the building of high speed engines of
+similar bore and stroke. The crank-shaft bearings are 2" in diameter by
+1-15/16" long, excepting the rear main bearing, which is 4-3/8" long,
+and front main bearing, which is 2-3/16" long. Steel oil scuppers are
+pinned and sweated onto the webs of the shaft, which allows of properly
+oiling the connecting rod bearings. Two thrust bearings are installed on
+the propeller end of the shaft, one for pull and the other for push. The
+propeller is driven by the crank-shaft flange, which is securely held in
+place upon the shaft by six keys. These drive an outside propeller
+flange, the propeller being clamped between them by six through bolts.
+The flange is fitted to a long taper on crank-shaft. This enables the
+propeller to be removed without disturbing the bolts. Timing gears and
+starting ratchets are bolted to a flange turned integral with shaft.
+
+The cam-shaft is of the one piece type, air pump eccentric, and gear
+flange being integral. It is made from a low carbon specially heat
+treated nickel forging, is first roughed out and drilled entire length;
+the cams are then formed, after which it is case hardened and ground to
+size. The cam-shaft bearings are extra long, made from Parson's White
+Brass. A small clutch is milled in gear end of shaft to drive revolution
+indicator. The cam-shaft is enclosed in an aluminum housing bolted
+directly on top of all six cylinders, being driven by a vertical shaft
+in connection with bevel gears. This shaft, in conjunction with rocker
+arms, rollers and other working parts, are oiled by forcing the oil into
+end of shaft, using same as a distributor, allowing the surplus supply
+to flow back into the crank-case through hollow vertical tube. This
+supply oils the magneto and pump gears. Extremely large Tungsten valves,
+being one-half the cylinder diameter, are seated in the cylinder heads.
+Large diameter oil tempered springs held in tool steel cups, locked with
+a key, are provided. The ports are very large and short, being designed
+to allow the gases to enter and exhaust with the least possible
+resistance. These valves are operated by overhead one piece cam-shaft in
+connection with short Chrome nickel rocker arms. These arms have
+hardened tool steel rollers on cam end with hardened tool steel
+adjusting screws opposite. This construction allows accurate valve
+timing at all speeds with least possible weight.
+
+
+CENSORED
+
+
+GERMAN AIRPLANE MOTORS
+
+In a paper on "Aviation Motors," presented by E. H. Sherbondy before the
+Cleveland section of the S. A. E. in June, 1917, the Mercedes and Benz
+airplane motor is discussed in some detail and portions of the
+description follow.
+
+[Illustration: Fig. 244.--Side and End Sectional Views of Four-Cylinder
+Argus Engine, a German 100 Horse-Power Design Having Bore and Stroke of
+140 mm., or 5.60 inches, and Developing Its Power at 1,368 R.P.M.
+Weight, 350 Pounds.]
+
+
+MERCEDES MOTOR
+
+The 150 horse-power six-cylinder Mercedes motor is 140 millimeters bore
+and 160 millimeters stroke. The Mercedes company started with
+smaller-sized cylinders, namely 100 millimeters bore and 140 millimeters
+stroke, six-cylinders. The principal features of the design are forged
+steel cylinders with forged steel elbows for gas passages, pressed steel
+water jackets, which when welded together forms the cylinder
+assembly, the use of inclined overhead valves operated by means of an
+overhead cam-shaft through rocker arms which multiply with the motion of
+the cam. By the use of steel cylinders, not only is the weight greatly
+reduced, but certain freedom from distortion through unequal sections,
+leaks and cracks are entirely avoided. The construction is necessarily
+very expensive. It is certainly a sound job. In the details of this
+construction there are a number of important things, such as finished
+gas passages, water-cooled valve guides and a very small mass of metal,
+which is water-cooled, surrounding the spark-plug. Of course, it is
+necessary to use very high compression in aviation motors in order to
+secure high power and economy and owing to the fact that aviation motors
+are worked at nearly their maximum, the heat flow through the cylinder,
+piston, and valves is many times higher than that encountered in
+automobile motors. It has been found necessary to develop special types
+of pistons to carry the heat from the center of the head in order to
+prevent pre-ignition. In the Mercedes motor the pistons have a drop
+forged steel head which includes the piston boss and this head is
+screwed into a cast iron skirt which has been machined inside to secure
+uniform wall thickness.
+
+
+CENSORED
+
+
+ [A] Piston Displacement (Cubic Inches)
+ [B] Weight of Engine with Carburetor and Ignition
+ [C] Gas Consumption
+
+ ===========+======+======+======+=======+====+======+====+=================
+ Maker's |Number|Bore |Stroke| | | | |
+ Name | of |(In- |(In- | | | | |
+ and Model | Cyl. |ches) |ches) | [A] |H.P.|R.P.M.| [B]| [C]
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Aeromarine | 6 |4-1/2 |5-1/8 | 449 | 85| 1400 | 440| ...
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Aeromarine | 12 |4-5/16|5-1/8 | ... | ...| ... | 750| ...
+ D-12 | | | | | | | |
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Curtiss OX | 8 |4 |5 | 502.6 | 90| 1400 | 375| ...
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Curtiss | 8 |4-1/4 |5 | 567.5 | 100| 1400 | 423| ...
+ OXX-2 | | | | | | | |
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Curtiss V-2| 8 |5 |7 |1100 | 200| 1400 | 690| ...
+ -----------+------+------+------+-------+----+------+----+-----------------
+ CENSORED
+ -----------+------+------+------+-------+----+------+----+-----------------
+ General Ve-| 9 |4.33 |5.9 | 848 | 100| 1200 | 272|12 gals/hour at
+ hicle Gnome Mono | | | | | | |rated H.P.
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Gyro K | 7 |4-1/2 |6 | ... | 90| 1250| 215|8 gals/hour at
+ Rotary, Le Rhone Type | | | | | |rated H.P.
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Gyro L | 9 |4-1/2 |6 | 859 | 100| 1200| 285|10 gals/hour at
+ Rotary, Le Rhone Type | | | | | |rated H.P.
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Hall-Scott | 4 |5 |7 | 550 | 90-| 1400| 410| ...
+ A-7 | | | | | 100| | |
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Hall-Scott | 6 |5 |7 | 825 | 125| 1300| 592| ...
+ A-5 | | | | | | | |
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Hispano- | 8 |4-5/8 |5 | 672 | 154| 1500| 455| ...
+ Suiza | | | | | | | |
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Knox Motors| 12 |4-3/4 |7 |1555 | 300| 1800|1425|31.5 gals/hour
+ Co. | | | | | | | |
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Maximotor | 6 |4-1/2 |5 | 477 | 85| 1600| 340| ...
+ A-6 | | | | | | | |
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Maximotor | 6 |5 |6 | 706.8 | 115| 1600| 385| ...
+ B-6 | | | | | | | |
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Maximotor | 8 |4-1/2 |5 | 636 | 115| 1600| 420| ...
+ A-8 | | | | | | | |
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Packard 12 | 12 |4 |6 | 903 | 225| 2100| 800| ...
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Sturtevant | 8 |4 |5-1/2 | 552.9 | 140| 2000| 580| ...
+ 5 | | | | | | | |
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Sturtevant | 8 |4 |5-1/2 | ... | 140| 2000| 514|13.75 gals/hour
+ 5-A | | | | | | | |
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Thomas 8 | 8 |4 |5-1/2 | 552.9 | 135| 2000| 630| ...
+ | | | | | | |lbs. with self-starter
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Thomas 88 | 8 |4-1/8 |5-1/2 | 552.9 | 150| 2100| 525| ...
+ | | | | | | |lbs. with self-starter
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Wisconsin | 6 |5 |6-1/2 | 765.7 | 140| 1380| 637| ...
+ -----------+------+------+------+-------+----+------+----+-----------------
+ Wisconsin | 12 |5 |6-1/2 |1531.4 | 250| 1200| ...| ...
+ -----------+------+------+------+-------+----+------+----+-----------------
+
+The carburetor used on this 150 horse-power Mercedes motor is precisely
+of the same type used on the Twin Six motor. It has two venturi throats,
+in the center of which is placed the gasoline spray nozzle of
+conventional type, fixed size orifices, immediately above which are
+placed two panel type throttles with side outlets. An idling or primary
+nozzle is arranged to discharge above the top of the venturi throat. The
+carburetor body is of cast aluminum and is water jacketed. It is bolted
+directly to air passage passing through the top and bottom half of the
+crank-case which passes down through the oil reservoir. The air before
+reaching the carburetor proper to some extent has cooled the oil in the
+crank chamber and has itself been heated to assist in the vaporization.
+The inlet pipes themselves are copper. All the passages between the
+venturi throat and the inlet valve have been carefully finished and
+polished. The only abnormal thing in the design of this motor is the
+short connecting rod which is considerably less than twice the stroke
+and would be considered very bad practice in motor car engines. A short
+connecting rod, however, possesses two very real virtues in that it cuts
+down height of the motor and the piston passes over the bottom dead
+center much more slowly than with a long rod.
+
+[Illustration: Fig. 245.--Part Sectional View of 90 Horse-Power Mercedes
+Engine, Which is Typical of the Design of Larger Sizes.]
+
+Other features of the design are a very stiff crank-case, both halves of
+which are bolted together by means of long through bolts, the
+crank-shaft main bearings are seated in the lower half of the case
+instead of in the usual caps and no provision is made for taking up the
+main bearings. The Mercedes company uses a plunger type of pump having
+mechanically operated piston valves and it is driven by means of worm
+gearing.
+
+The overhead cam-shaft construction is extremely light. The cam-shaft is
+mounted in a nearly cylindrical cast bronze case and is driven by means
+of bevel gears from the crank-shaft. The vertical bevel gear shaft
+through which the drive is taken from the crank-shaft to the cam-shaft
+operates at one and one-half times the crank-shaft speeds and the
+reduction to the half-time cam-shaft is secured through a pair of
+bevels. On this vertical shaft there is mounted the water pump and a
+bevel gear for driving two magnetos. The water pump mounted on this
+shaft tends to steady the drive and avoid vibration in the gearing.
+
+The cylinder sizes of six-cylinder aviation motors which have been built
+by Mercedes are
+
+ Bore Stroke Horse-power
+ 105 mm. 140 mm. 100
+ 120 mm. 140 mm. 135
+ 140 mm. 150 mm. 150
+ 140 mm. 160 mm. 160
+
+The largest of these motors has recently had its horse-power increased
+to 176 at 1450 R. P. M. This general design of motor has been the
+foundation for a great many other aviation motor designs, some of which
+have proved very successful but none of which is equal to the original.
+Among the motors which follow more or less closely the scheme of design
+and arrangement are the Hall-Scott, the Wisconsin motor, the Renault
+water-cooled, the Packard, the Christofferson and the Rolls-Royce. Each
+of these motors show considerable variation in detail. The Rolls-Royce
+and Renault are the only ones who have used the steel cylinder with the
+steel jacket. The Wisconsin motor uses an aluminum cylinder with a
+hardened steel liner and cast-iron valve seats. The Christofferson has
+somewhat similar design to the Wisconsin with the exception that the
+valve seats are threaded into the aluminum jacket and the cylinder head
+has a blank end which is secured to the aluminum casting by means of the
+valve seat pieces. The Rolls-Royce motors show small differences in
+details of design in cylinder head and cam-shaft housing from the
+Mercedes on which it has taken out patents, not only abroad but in this
+country.
+
+
+THE BENZ MOTOR
+
+In the Kaiser prize contest for aviation motors a four-cylinder Benz
+motor of 130 by 180 mm. won first prize, developing 103 B. H. P. at 1290
+R. P. M. The fuel consumption was 210 grams per horse-power hour. Total
+weight of the motor was 153 kilograms. The oil consumption was .02 of a
+kilogram per horse-power hour. This motor was afterward expanded into a
+six-cylinder design and three different sizes were built.
+
+The accompanying table gives some of the details of weight, horse-power,
+etc.
+
+ Motor type B FD FF
+ Rated horse-power 85 100 150
+ Horse-power at 1250 r.p.m 88 108 150
+ Horse-power at 1350 r.p.m 95 115 160
+ Bore in millimeters 106 116 130
+ Stroke in millimeters 150 160 180
+ Offset of the cylinders in millimeters 18 20 20
+ Rate of gasoline consumption in grams 240 230 225
+ Oil consumption in grams per b.h.p. hour 10 10 10
+ Oil capacity in kilograms 36 4 4-1/2
+ Water capacity in litres 5-1/2 7-1/2 9-1/2
+ The weight with water and oil but with
+ two magnetos, fuel feeder and air pump in
+ kilograms 170 200 245
+ The weight of motors, including the water
+ pump, two magnetos, double ignition, etc. 160 190 230
+ The weight of the exhaust pipe, complete
+ in kilograms 4 4.8 5-1/2
+ The weight of the propeller hub in
+ kilograms. 3-1/2 4 4
+
+The Benz cylinder is a simple, straightforward design and a very
+reliable construction and not particularly difficult to manufacture. The
+cylinder is cast of iron without a water jacket but including 45
+degrees angle elbows to the valve ports. The cylinders are machined
+wherever possible and at other points have been hand filed and scraped,
+after which a jacket, which is pressed in two halves, is gas welded by
+means of short pipes welded on to the jacket. The bottom and the top of
+the cylinders become water galleries, and by this means separate water
+pipes with their attendant weight and complication are eliminated.
+Rubber rings held in aluminum clamps serve to connect the cylinders
+together. The whole construction turns out very neat and light. The
+cylinder walls are 4 mm. or 3/16" thick and the combustion chamber is of
+cylindrical pancake form and is 140 mm. or 5.60 inch in diameter. The
+valve seats are 68 mm. in diameter and the valve port is 62 mm. in
+diameter.
+
+The passage joining the port is 57 mm. in diameter. In order to insert
+the valves into the cylinder the valve stem is made with two diameters
+and the valve has to be cocked to insert it in the guide, which has a
+bronze bushing at its upper end to compensate for the smaller valve stem
+diameter. The valve stem is 14 mm. or 9/16" in diameter and is reduced
+at its upper portion to 9-1/2 mm. The valves are operated through a push
+rod and rocker arm construction, which is 7/16" and exceedingly light.
+Rocker arm supports are steel studs with enlarged heads to take a double
+row ball bearing. A roller is mounted at one end of the rocker arm to
+impinge on the end of the valve stem, and the rocker arm has an
+adjustable globe stud at the other end. The push rods are light steel
+tubes with a wall thickness of 0.75 mm. and have a hardened steel cup at
+their upper end to engage the rocker arm globe stud and a hardened steel
+globe at their lower end to socket in the roller plunger.
+
+The Benz cam-shaft has a diameter of 26 mm. and is bored straight
+through 18 mm. and there is a spiral gear made integrally with the shaft
+in about the center of its length for driving the oil pump gear. The cam
+faces are 10 mm. wide. There is also, in addition to the intake and
+exhaust cams, a set of half compression cams. The shaft is moved
+longitudinally in its bearings by means of an eccentric to put these
+cams into action. At the fore end of the shaft is a driving gear flange
+which is very small in diameter and very thin. The flange is 68 mm. in
+diameter and 4 mm. thick and is tapped to take 6 mm. bolts. The total
+length of cam-shaft is 1038 mm., and it becomes a regular gun boring job
+to drill a hole of this length.
+
+The cam-shaft gear is 140 mm. or 5-1/2 inches outside diameter. It has
+fifty-four teeth and the gear face is 15 mm. or 19/32". The flange and
+web have an average thickness of 4 mm. or 5/32" and the web is drilled
+full of holes interposed between the spur gear mounted on the cam-shaft
+and the cam-shaft gear. There is a gear which serves to drive the
+magnetos and tachometer, also the air pump. The shaft is made integrally
+with this gear and has an eccentric portion against which the air pump
+roll plunger impinges.
+
+The seven-bearing crank-shaft is finished all over in a beautiful
+manner, and the shaft out of the particular motor we have shows no signs
+of wear whatever. The crank-pins are 55 mm. in diameter and 69 mm. long.
+Through both the crank-pin and main bearings there is drilled a 28 mm.
+hole, and the crank cheeks are plugged with solder. The crank cheeks are
+also built to convey the lubricant to the crank-pins. At the fore end of
+the crank cheek there is pressed on a spur driving gear. There is
+screwed on to the front end of the shaft a piece which forms a bevel
+water pump driving gear and the starting dog. At the rear end of the
+shaft very close to the propeller hub mounting there is a double thrust
+bearing to take the propeller thrust.
+
+Long, shouldered studs are screwed into the top half of the crank-case
+portion of the case and pass clean through the bottom half of the case.
+The case is very stiff and well ribbed. The three center bearing
+diaphragms have double walls. The center one serves as a duct through
+which water pipe passes, and those on either side of the center form the
+carburetor intake air passages and are enlarged in section at one side
+to take the carburetor barrel throttle.
+
+The pistons are of cast iron and carry three concentric rings 1/4 inch
+wide on their upper end, which are pinned at the joint. The top of the
+piston forms the frustum of the cone and the pistons are 110 mm. in
+length. The lower portion of the skirt is machined inside and has a wall
+thickness of 1 mm. Riveted to the piston head is a conical diaphragm
+which contacts with the piston pin when in place and serves to carry the
+heat off the center of the piston.
+
+The oil pump assembly comprises a pair of plunger pumps which draw oil
+from a separate outside pump, and constructed integrally with it is a
+gear pump which delivers the oil under about 60 pound pressure through a
+set of copper pipes in the base to the main bearings. The plunger oil
+pump shows great refinement of detail. A worm wheel and two eccentrics
+are machined up out of one piece and serve to operate the plungers.
+
+[Illustration: Fig. 246.--Part Sectional Side View and Sectional End
+View of Benz 160 Horse-Power Aviation Engine.]
+
+Some interesting details of the 160 horse-power Benz motor, which is
+shown at Fig. 246, are reproduced from the "Aerial Age Weekly," and show
+how carefully the design has been considered.
+
+ Maximum horse-power, 167.5 B. H. P.
+ Speed at maximum horse-power, 1,500 R. P. M.
+ Piston speed at maximum horse-power, 1,770 ft. per minute.
+ Normal horse-power, 160 B. H. P.
+ Speed at normal horse-power, 1,400 R. P. M.
+ Piston speed at normal horse-power, 1,656 ft. per minute.
+ Brake mean pressure at maximum horse-power, 101.2 pound per square
+ inch.
+ Brake mean pressure at normal horse-power, 103.4 pound per square
+ inch.
+ Specific power cubic inch swept volume per B. H. P., 5.46 cubic inch;
+ 160 B. H. P.
+ Weight of piston, complete with gudgeon pin, rings, etc., 5.0 pound.
+ Weight of connecting rod, complete with bearings, 4.99 pound; 1.8
+ pound reciprocating.
+ Weight of reciprocating parts per cylinder, 6.8 pound.
+ Weight of reciprocating parts per square inch of piston area, 0.33
+ pound.
+ Outside diameter of inlet valve, 68 mm.; 2.68 inches.
+ Diameter of inlet valve port (_d_), 61.5 mm.; 2.42 inches.
+ Maximum lift of inlet valve (_h_), 11 mm.; 0.443 inch.
+ Area of inlet valve opening ([pi] _d_ _h_), 21.25 square cm.; 3.29
+ square inches.
+ Inlet valve opens, degrees on crank, top dead center.
+ Inlet valve closes, degrees on crank, 60 deg. late; 35 mm. late.
+ Outside diameter of exhaust valve, 68 mm.; 2.68 inches.
+ Diameter of exhaust valve port (_d_), 61.5 mm.; 2.42 inches.
+ Maximum lift of exhaust valve (_h_) 11 mm.; 0.433 inch.
+ Area of exhaust valve opening ([pi] _d_ _h_), 21.25 square cm.; 3.29
+ square inches.
+ Exhaust valve opens, degrees on crank, 60 deg. early; 35 mm. early.
+ Exhaust valve closes, degrees on crank, 16-1/2 deg. late; 5 mm. late.
+ Length of connecting rod between centers, 314 mm.; 12.36 inches.
+ Ratio connecting rod to crank throw, 3.49:1.
+ Diameter of crank-shaft, 55 mm. outside, 2.165 inches; 28 mm. inside,
+ 1.102 inches.
+ Diameter of crank-pin, 55 mm. outside, 2.165 inches; 28 mm. inside,
+ 1.102 inches.
+ Diameter of gudgeon pin, 30 mm. outside, 1.181 inches; 19 mm. inside,
+ 0.708 inch.
+ Diameter of cam-shaft, 26 mm. outside, 1.023 inches; 18 mm. inside,
+ 0.708 inch.
+ Number of crank-shaft bearings, 7.
+ Projected area of crank-pin bearings, 36.85 square cm.; 5.72 square
+ inches.
+ Projected area of gudgeon pin bearings, 22.20 square cm.; 3.44 square
+ inches.
+ Firing sequence, 1, 5, 3, 6, 2, 4.
+ Type of magnetos, ZH6 Bosch.
+ Direction of rotation of magneto from driving end, one clock, one
+ anti-clock.
+ Magneto timing, full advance, 30 deg. early (16 mm. early).
+ Type of carburetors (2) Benz design.
+ Fuel consumption per hour, normal horse-power, 0.57 pint.
+ Normal speed of propeller, engine speed, 1,400 R. P. M.
+
+
+AUSTRO-DAIMLER ENGINE
+
+One of the first very successful European flying engines which was
+developed in Europe is the Austro-Daimler, which is shown in end section
+in a preceding chapter. The first of these motors had four-cylinders,
+120 by 140 millimeters, bore and stroke, with cast iron cylinders,
+overhead valves operated by means of a single rocker arm, controlled by
+two cams and the valves were closed by a single leaf spring which
+oscillates with the rocker arm. The cylinders are cast singly and have
+either copper or steel jackets applied to them. The four-cylinder design
+was afterwards expanded to the six-cylinder design and still later a
+six-cylinder motor of 130 by 175 millimeters was developed. This motor
+uses an offset crank-shaft, as does the Benz motor, and the effect of
+offset has been discussed earlier on in this treatise. The Benz motor
+also uses an offset cam-shaft which improves the valve operation and
+changes the valve lift diagram. The lubrication also is different than
+any other aviation motor, since individual high pressure metering pumps
+are used to deliver fresh oil only to the bearings and cylinders, as was
+the custom in automobile practice some ten years ago.
+
+
+SUNBEAM AVIATION ENGINES
+
+These very successful engines have been developed by Louis Coatalen. At
+the opening of the war the largest sized Coatalen motor was 225
+horse-power and was of the L-head type having a single cam-shaft for
+operating valves and was an evolution from the twelve-cylinder racing
+car which the Sunbeam Company had previously built. Since 1914 the
+Sunbeam Company have produced engines of six-, eight-, twelve- and
+eighteen-cylinders from 150 to 500 horse-power with both iron and
+aluminum cylinders. For the last two years all the motors have had
+overhead cam-shafts with a separate shaft for operating the intake and
+exhaust valves. Cam-shafts are connected through to the crank-shaft by
+means of a train of spur gears, all of which are mounted on two double
+row ball bearings. In the twin six, 350 horse-power engine, operating at
+2100 R. P. M., requires about 4 horse-power to operate the cam-shafts.
+This motor gives 362 horse-power at 2100 revolutions and has a fuel
+consumption of 51/100 of a pint per brake horse-power hour. The
+cylinders are 110 by 160 millimeters. The same design has been expanded
+into an eighteen-cylinder which gives 525 horse-power at 2100 turns.
+There has also been developed a very successful eight-cylinder motor
+rated at 2220 horse-power which has a bore and stroke of 120 by 130
+millimeters, weight 450 pounds. This motor is an aluminum block
+construction with steel sleeves inserted. Three valves are operated, one
+for the inlet and two for the exhaust. One cam-shaft operates the three
+valves.
+
+[Illustration: Fig. 247.--At Top, the Sunbeam Overhead Valve 170
+Horse-Power Six-Cylinder Engine. Below, Side View of Sunbeam 350
+Horse-Power Twelve-Cylinder Vee Engine.]
+
+The modern Sunbeam engines operate with a mean effective pressure of 135
+pounds with a compression ratio of 6 to 1 sea level. The connecting rods
+are of the articulated type as in the Renault motor and are very short.
+The weight of these motors turns out at 2.6 pounds per brake
+horse-power, and they are able to go through a 100 hour test without any
+trouble of any kind. The lubricating system comprises a dry base and oil
+pump for drawing the oil off from the base, whence it is delivered to
+the filter and cooling system. It then is pumped by a separate high
+pressure gear pump through the entire motor. In these larger European
+motors, castor-oil is used largely for lubrication. It is said that
+without the use of castor-oil it is impossible to hold full power for
+five hours. Coatalen favors aluminum cylinders rather than cast iron.
+The series of views in Figs. 247 to 250 inclusive, illustrates the
+vertical, narrow type of engine; the V-form; and the broad arrow type
+wherein three rows, each of six-cylinders, are set on a common
+crank-case. In this water-cooled series the gasoline and oil consumption
+are notably low, as is the weight per horse-power.
+
+[Illustration: Fig. 248.--Side View of Eighteen-Cylinder Sunbeam
+Coatalen Aircraft Engine Rated at 475 B.H.P.]
+
+[Illustration: Fig. 249.--Sunbeam Eighteen-Cylinder Motor, Viewed from
+Pump and Magneto End.]
+
+In the eighteen-cylinder overhead valve Sunbeam-Coatalen aircraft engine
+of 475 brake horse-power, there are no fewer than half a dozen magnetos.
+Each magneto is inclosed. Two sparks are furnished to each cylinder
+from independent magnetos. On this engine there are also no fewer than
+six carburetors. Shortness of crank-shaft, and therefore of engine
+length, and absence of vibration are achieved by the linking of the
+connecting-rods. Those concerned with three-cylinders in the broad arrow
+formation work on one crank-pin, the outer rods being linked to the
+central master one. In consequence of this arrangement, the piston
+travel in the case of the central row of cylinders is 160 mm., while the
+stroke of the pistons of the cylinders set on either side is in each
+case 168 mm. Inasmuch as each set of six-cylinders is completely
+balanced in itself, this difference in stroke does not affect the
+balance of the engine as a whole. The duplicate ignition scheme also
+applies to the twelve-cylinder 350 brake horse-power Sunbeam-Coatalen
+overhead valve aircraft engine type. It is distinguishable,
+incidentally, by the passage formed through the center of each induction
+pipe for the sparking plug in the center cylinder of each block of
+three. In this, as in the eighteen-cylinder and the six-cylinder types,
+there are two cam-shafts for each set of cylinders. These cam-shafts are
+lubricated by low pressure and are operated through a train of inclosed
+spur wheels at the magneto end of the machine. The six-cylinder, 170
+brake horse-power vertical type employs the same general principles,
+including the detail that each carburetor serves gas to a group of
+three-cylinders only. It will be observed that this engine presents
+notably little head resistance, being suitable for multi-engined
+aircraft.
+
+[Illustration: Fig. 250.--Propeller End of Sunbeam Eighteen-Cylinder 475
+B.H.P. Aviation Engine.]
+
+
+INDICATING METERS FOR AUXILIARY SYSTEMS
+
+[Illustration: Fig. 251.--View of Airplane Cowl Board, Showing the
+Various Navigating and Indicating Instruments to Aid the Aviator in
+Flight.]
+
+The proper functioning of the power plant and the various groups
+comprising it may be readily ascertained at any time by the pilot
+because various indicating meters and pressure gauges are provided which
+are located on a dash or cowl board in front of the aviator, as shown at
+Fig. 251. The speed indicator corresponds to the speedometer of an
+automobile and gives an indication of the speed the airplane is making,
+which taken in conjunction with the clock will make it possible to
+determine the distance covered at a flight. The altimeter, which is an
+aneroid barometer, outlines with fair accuracy the height above the
+ground at which a plane is flying. These instruments are furnished to
+enable the aviator to navigate the airplane when in the air, and if the
+machine is to be used for cross-country flying, they may be supplemented
+by a compass and a drift set. It will be evident that these are purely
+navigating instruments and only indicate the motor condition in an
+indirect manner. The best way of keeping track of the motor action is to
+watch the tachometer or revolution counter which is driven from the
+engine by a flexible shaft. This indicates directly the number of
+revolutions the engine is making per minute and, of course, any slowing
+up of the engine in normal flights indicates that something is not
+functioning as it should. The tachometer operates on the same principle
+as the speed indicating device or speedometer used in automobiles except
+that the dial is calibrated to show revolutions per minute instead of
+miles per hour. At the extreme right of the dash at Fig. 251 the spark
+advance and throttle control levers are placed. These, of course,
+regulate the motor speed just as they do in an automobile. Next to the
+engine speed regulating levers is placed a push button cut-out switch to
+cut out the ignition and stop the motor. Three pressure gauges are
+placed in a line. The one at the extreme right indicates the pressure of
+air on the fuel when a pressure feed system is used. The middle one
+shows oil pressure, while that nearest the center of the dash board is
+employed to show the air pressure available in the air starting system.
+It will be evident that the character of the indicating instruments will
+vary with the design of the airplane. If it was provided with an
+electrical starter instead of an air system electrical indicating
+instruments would have to be provided.
+
+
+COMPRESSED AIR-STARTING SYSTEMS
+
+Two forms of air-starting systems are in general use, one in which the
+crank-shaft is turned by means of an air motor, the other class where
+compressed air is admitted to the cylinders proper and the motor turned
+over because of the air pressure acting on the engine pistons. A system
+known as the "Never-Miss" utilizes a small double-cylinder air pump is
+driven from the engine by means of suitable gearing and supplies air to
+a substantial container located at some convenient point in the
+fuselage. The air is piped from the container to a dash-control valve
+and from this member to a peculiar form of air motor mounted near the
+crank-shaft. The air motor consists of a piston to which a rack is
+fastened which engages a gear mounted on the crank shaft provided with
+some form of ratchet clutch to permit it to revolve only in one
+direction, and then only when the gear is turning faster than the engine
+crank-shaft.
+
+The method of operation is extremely simple, the dash-control valve
+admitting air from the supply tank to the top of the pump cylinder. When
+in the position shown in cut the air pressure will force the piston and
+rack down and set the engine in motion. A variety of air motors are used
+and in some the pump and motor may be the same device, means being
+provided to change the pump to an air motor when the engine is to be
+turned over.
+
+The "Christensen" air starting system is shown at Figs. 252 and 253. An
+air pump is driven by the engine, and this supplies air to an air
+reservoir or container attached to the fuselage. This container
+communicates with the top of an air distributor when a suitable control
+valve is open. An air pressure gauge is provided to enable one to
+ascertain the air pressure available. The top of each cylinder is
+provided with a check valve, through which air can flow only in one
+direction, i.e., from the tank to the interior of the cylinder. Under
+explosive pressure these check valves close. The function of the
+distributor is practically the same as that of an ignition timer, its
+purpose being to distribute the air to the cylinders of the engine only
+in the proper firing order. All the while that the engine is running and
+the car is in motion the air pump is functioning, unless thrown out of
+action by an easily manipulated automatic control. When it is desired to
+start the engine a starting valve is opened which permits the air to
+flow to the top of the distributor, and then through a pipe to the check
+valve on top of the cylinder about to explode. As the air is going
+through under considerable pressure it will move the piston down just as
+the explosion would, and start the engine rotating. The inside of the
+distributor rotates and directs a charge of air to the cylinder next to
+fire. In this way the engine is given a number of revolutions, and
+finally a charge of gas will be ignited and the engine start off on its
+cycle of operation. To make starting positive and easier some gasoline
+is injected in with the air so an inflammable mixture is present in the
+cylinders instead of air only. This ignites easily and the engine starts
+off sooner than would otherwise be the case. The air pressure required
+varies from 125 to 250 pounds per square inch, depending upon the size
+and type of the engine to be set in motion.
+
+[Illustration: Fig. 252.--Parts of Christensen Air Starting System Shown
+at A, and Application of Piping and Check Valves to Cylinders of
+Thomas-Morse Aeromotor Outlined at B.]
+
+[Illustration: Fig. 253.--Diagrams Showing Installation of Air Starting
+System on Thomas-Morse Aviation Motor.]
+
+
+ELECTRIC STARTING SYSTEMS
+
+Starters utilizing electric motors to turn over the engine have been
+recently developed, and when properly made and maintained in an
+efficient condition they answer all the requirements of an ideal
+starting device. The capacity is very high, as the motor may draw
+current from a storage battery and keep the engine turning over for
+considerable time on a charge. The objection against their use is that
+it requires considerable complicated and costly apparatus which is
+difficult to understand and which requires the services of an expert
+electrician to repair should it get out of order, though if battery
+ignition is used the generator takes the place of the usual ignition
+magneto.
+
+In the Delco system the electric current is generated by a combined
+motor-generator permanently geared to the engine. When the motor is
+running it turns the armature and the motor generator is acting as a
+dynamo, only supplying current to a storage battery. On account of the
+varying speeds of the generator, which are due to the fluctuation in
+engine speed, some form of automatic switch which will disconnect the
+generator from the battery at such times that the motor speed is not
+sufficiently high to generate a current stronger than that delivered by
+the battery is needed. These automatic switches are the only delicate
+part of the entire apparatus, and while they require very delicate
+adjustment they seem to perform very satisfactorily in practice.
+
+When it is desired to start the engine an electrical connection is
+established between the storage battery and the motor-generator unit,
+and this acts as a motor and turns the engine over by suitable gearing
+which engages the gear teeth cut into a special gear or disc attached to
+the engine crank-shaft. When the motor-generator furnishes current for
+ignition as well as for starting the motor, the fact that the current
+can be used for this work as well as starting justifies to a certain
+extent the rather complicated mechanism which forms a complete starting
+and ignition system, and which may also be used for lighting if
+necessary in night flying.
+
+An electric generator and motor do not complete a self-starting system,
+because some reservoir or container for electric current must be
+provided. The current from the generator is usually stored in a storage
+battery from which it can be made to return to the motor or to the same
+armature that produced it. The fundamental units of a self-starting
+system, therefore, are a generator to produce the electricity, a storage
+battery to serve as a reservoir, and an electric motor to rotate the
+motor crank-shaft. Generators are usually driven by enclosed gearing,
+though silent chains are used where the center distance between the
+motor shaft and generator shaft is too great for the gears. An electric
+starter may be directly connected to the gasoline engine, as is the case
+where the combined motor-generator replaces the fly-wheel in an
+automobile engine. The motor may also drive the engine by means of a
+silent chain or by direct gear reduction.
+
+Every electric starter must use a switch of some kind for starting
+purposes and most systems include an output regulator and a reverse
+current cut-out. The output regulator is a simple device that regulates
+the strength of the generator current that is supplied the storage
+battery. A reverse current cut-out is a form of check valve that
+prevents the storage battery from discharging through the generator.
+Brief mention is made of electric starting because such systems will
+undoubtedly be incorporated in some future airplane designs. Battery
+ignition is already being experimented with.
+
+
+BATTERY IGNITION SYSTEM PARTS
+
+A battery ignition system in its simplest form consists of a current
+producer, usually a set of dry cells or a storage battery, an induction
+coil to transform the low tension current to one having sufficient
+strength to jump the air gap at the spark-plug, an igniter member
+placed in the combustion chamber and a timer or mechanical switch
+operated by the engine so that the circuit will be closed only when it
+is desired to have a spark take place in the cylinders. Battery ignition
+systems may be of two forms, those in which the battery current is
+stepped up or intensified to enable it to jump an air gap between the
+points of the spark plug, these being called "high tension" systems and
+the low tension form (never used on airplane motors) in which the
+battery current is not intensified to a great degree and a spark
+produced in the cylinder by the action of a mechanical circuit breaker
+in the combustion chamber. The low tension system is the simplest
+electrically but the more complex mechanically. The high tension system
+has the fewest moving parts but numerous electrical devices. At the
+present time all airplane engines use high tension ignition systems, the
+magneto being the most popular at the present time. The current
+distribution and timing devices used with modern battery systems are
+practically the same as similar parts of a magneto.
+
+
+
+
+INDEX
+
+
+ PAGE
+
+ A
+
+ Action of Four-cycle Engine 38
+ Action of Le Rhone Rotary Engine 503
+ Action of Two-cycle Engine 41
+ Action of Vacuum Feed System 119
+ Actual Duration of Different Functions 93
+ Actual Heat Efficiency 62
+ Adiabatic Diagram 51
+ Adiabatic Law 50
+ Adjustment of Bearings 449
+ Adjustment of Carburetors 151
+ Aerial Motors, Must be Light 20
+ Aerial Motors, Operating Conditions of 19
+ Aerial Motors, Requirements of 19
+ Aeromarine Six-cylinder Engine 527
+ Aeronautics, Division in Branches 18
+ Aerostatics 18
+ Air-cooled Engine Design 229
+ Air-cooling Advantages 231
+ Air-cooling, Direct Method 228
+ Air-cooling Disadvantages 231
+ Air-cooling Systems 223
+ Aircraft, Heavier Than Air 17
+ Aircraft, Lighter Than Air 18
+ Aircraft Types, Brief Consideration of 17
+ Air Needed to Burn Gasoline 113
+ Airplane Engine, Power Needed 21
+ Airplane Engines, Overhauling 412
+ Airplane Engine, How to Time 269
+ Airplane Engine Lubrication 209
+ Airplane, How Supported 21
+ Airplane Motors, German 543
+ Airplane Motor Types 20
+ Airplane Motors, Weight of 21
+ Airplane Power Plant Installation 324
+ Airplane Types 18
+ Airplanes, Horse-power Used in 26
+ Air Pressure Diminution, With Altitude 144
+ Altitude, How it Affects Mixture 153
+ Aluminum, Use in Pistons 297
+ American Aviation Engines, Statistics 546
+ Anzani Radial Engine Installation 344
+ Anzani Six-cylinder Star Engine 465
+ Anzani Six-cylinder Water-cooled Engine 459
+ Anzani Ten- and Twenty-cylinder Engines 468
+ Anzani Three-cylinder Engine 459
+ Anzani Three-cylinder Y Type 462
+ Argus Engine Construction 545
+ Armature Windings 168
+ Atmospheric Conditions, Compensating For 143
+ Austro-Daimler Engine 557
+ Aviatics 18
+ Aviation Engine, Aeromarine 527
+ Aviation Engine, Anzani Six-cylinder Star 465
+ Aviation Engine, Canton and Unne 469
+ Aviation Engine Cooling 219
+ Aviation Engine, Curtiss 519
+ Aviation Engine Cylinders 233
+ Aviation Engine, Early Gnome 472
+ Aviation Engine, German Gnome Type 495
+ Aviation Engine, Gnome Monosoupape 486
+ Aviation Engine, How To Dismantle 415
+ Aviation Engine, How to Start 460
+ Aviation Engine, Le Rhone Rotary 495
+ Aviation Engine Oiling 218
+ Aviation Engine Parts, Functions of 82
+ Aviation Engine, Renault Air-cooled 507
+ Aviation Engine, Stand for Supporting 414
+ Aviation Engine, Sturtevant 515
+ Aviation Engine, Thomas-Morse 521
+ Aviation Engine Types 457
+ Aviation Engine, Wisconsin 531
+ Aviation Engines, Anzani Six-cylinder Water-cooled 459
+ Aviation Engines, Anzani Ten- and Twenty-cylinder 468
+ Aviation Engines, Anzani Three-cylinder 459
+ Aviation Engines, Anzani Y Type 462
+ Aviation Engines, Argus 545
+ Aviation Engines, Austro-Daimler 557
+ Aviation Engines, Benz 551
+ Aviation Engines, Four- and Six-cylinder 88
+ Aviation Engines, German 543
+ Aviation Engines, Hall-Scott 539
+ Aviation Engines, Hispano-Suiza 512
+ Aviation Engines, Mercedes 543
+ Aviation Engines, Overhauling 412
+ Aviation Engines, Principal Parts of 80
+ Aviation Engines, Starting Systems For 567
+ Aviation Engines, Sunbeam 558
+
+ B
+
+ Balanced Crank-shafts 318
+ Ball-bearing Crank-shafts 319
+ Battery Ignition Systems 571
+ Baverey Compound Nozzle 137
+ Bearings, Adjustment of 449
+ Bearing Alignment 453
+ Bearing Brasses, Fitting 450
+ Bearing Parallelism, Testing 453
+ Bearing Scrapers and Their Use 446
+ Benz Aviation Engines 551
+ Benz Engine Statistics 551
+ Berling Magneto 174
+ Berling Magneto, Adjustment of 180
+ Berling Magneto Care 180
+ Berling Magneto Circuits 176
+ Berling Magneto, Setting 178
+ Block Castings 234
+ Blowing Back 269
+ Bolts, Screwing Down 452
+ Bore and Stroke Ratio 240
+ Boyle's Law 49
+ Brayton Engine 48
+ Breaker Box, Adjustment of 180
+ Breast and Hand Drills 387
+ Burning Out Carbon Deposits 421
+ Bushings, Cam-shaft, Wear in 456
+
+ C
+
+ Calipers, Inside and Outside 398
+ Cam Followers, Types of 260
+ Cams for Valve Actuation 259
+ Cam-shaft Bushings 456
+ Cam-shaft Design 313
+ Cam-shaft Drive Methods 261
+ Cam-shaft Testing 451
+ Cam-shafts and Timing Gears 456
+ Canton and Unne Engine 469
+ Carbon, Burning out with Oxygen 421
+ Carbon Deposits, Cause of 418
+ Carbon Removal 419
+ Carbon Scrapers, How Used 420
+ Carburetion Principles 112
+ Carburetion System Troubles 355
+ Carburetor, Claudel 127
+ Carburetor, Compound Nozzle Zenith 135
+ Carburetor, Concentric Float and Jet Type 125
+ Carburetor, Duplex Zenith 138
+ Carburetor, Duplex Zenith, Trouble in 357
+ Carburetor Installation, In Airplanes 148
+ Carburetor, Le Rhone 501
+ Carburetor, Master Multiple Jet 133
+ Carburetor, Schebler 125
+ Carburetor Troubles, How to Locate 354
+ Carburetor, Two Stage 131
+ Carburetor, What it Should Do 114
+ Carburetors, Float Feed 122
+ Carburetors, Multiple Nozzle 130
+ Carburetors, Notes on Adjustment 151
+ Carburetors, Reversing Position of 149
+ Carburetors, Spraying 120
+ Care of Dixie Magneto 188
+ Castor Oil, for Cylinder Lubrication 205
+ Castor Oil, Why Used In Gnome Engines 211
+ Center Gauge 403
+ Chisels, Forms of 384
+ Christensen Air Starting System 567
+ Circuits, Magnetic 161
+ Classification of Engines 458
+ Claudel Carburetor 127
+ Cleaning Distributor 180
+ Clearances Between Valve Stem and Actuators 261
+ Combustion Chamber Design 239
+ Combustion Chambers, Spherical 76
+ Common Tools, Outfit of 378
+ Comparing Two-cycle and Four-cycle Types 44
+ Compound Cam Followers 260
+ Compound Piston Rings 301
+ Compressed Air Starting System 565
+ Compression, Factors Limiting 69
+ Compression, in Explosive Motors, Value of 68
+ Compression Pressures, Chart for 72
+ Compression Temperature 71
+ Computations for Horse-power Needed 25
+ Computations for Temperature 52
+ Concentric Piston Ring 299
+ Concentric Valves 255
+ Connecting Rod Alignment, Testing 454
+ Connecting Rod, Conventional 308
+ Connecting Rod Forms 305
+ Connecting Rod, Gnome Engine 305
+ Connecting Rods, Fitting 449
+ Connecting Rods for Vee Engines 310
+ Connecting Rods, Le Rhone 498
+ Connecting Rods, Master 310
+ Constant Level Splash System 215
+ Construction of Dixie Magneto 186
+ Construction of Pistons 288
+ Conversion of Heat to Power 58
+ Cooling by Air 223
+ Cooling by Positive Water Circulation 224
+ Cooling, Heat Loss in 66
+ Cooling System Defects 358
+ Cooling Systems Used 223
+ Cooling Systems, Why Needed 219
+ Cotter Pin Pliers 384
+ Crank-case, Conventional 320
+ Crank-case Forms 320
+ Crank-case, Gnome 323
+ Crank-shaft, Built Up 315
+ Crank-shaft Construction 315
+ Crank-shaft Design 315
+ Crank-shaft Equalizer 449
+ Crank-shaft Form 315
+ Crank-shaft, Gnome Engine 483
+ Crank-shafts, Balanced 318
+ Crank-shafts, Ball Bearing 319
+ Cross Level 403
+ Crude Petroleum, Distillates of 111
+ Curtiss Aviation Engines 519
+ Curtiss Engine Installation 328
+ Curtiss Engine Repairing Tools 408
+ Cutting Oil Grooves 448
+ Cylinder Blocks, Advantages of 237
+ Cylinder Block, Duesenberg 235
+ Cylinder Castings, Individual 234
+ Cylinder Construction 233
+ Cylinder Faults and Correction 416
+ Cylinder Form and Crank-shaft Design 238
+ Cylinder Head Packings 417
+ Cylinder Head, Removable 239
+ Cylinder, I Head Form 248
+ Cylinder, L Head Form 248
+ Cylinder Oils 206
+ Cylinder Placing 20
+ Cylinder Placing in V Motor 99
+ Cylinder Retention, Gnome 475
+ Cylinder, T Head Form 248
+ Cylinders, Cast in Blocks 235
+ Cylinders, Odd Number in Rotary Engines 482
+ Cylinders, Repairing Scored 423
+ Cylinders, Valve Location in 245
+
+ D
+
+ Defects in Cylinders 417
+ Defects in Dry Battery 373
+ Defects in Fuel System 354
+ Defects in Induction Coil 373
+ Defects in Magneto 372
+ Defects in Storage Battery 372
+ Defects in Timer 373
+ Defects in Wiring and Remedies 373
+ Die Holder 394
+ Dies for Thread Cutting 395
+ Diesel Motor Cards 67
+ Diesel System 144
+ Direct Air Cooling 228
+ Dirigible Balloons 18
+ Dismantling Airplane Engine 415
+ Distillates of Crude Petroleum 111
+ Division of Circle in Degrees 268
+ Dixie Ignition Magneto 184
+ Dixie Magneto, Care of 188
+ Draining Oil From Crank-case 214
+ Drilling Machines 386
+ Drills, Types and Use 388
+ Driving Cam-shaft, Methods of 262
+ Dry Cell Battery, Defects in 373
+ Duesenberg Sixteen Valve Engine 525
+ Duesenberg Valve Action 255
+ Duplex Zenith Carburetor 138
+
+ E
+
+ Early Gnome Motor, Construction of 472
+ Early Ignition Systems 155
+ Early Types of Gas Engine 28
+ Early Vaporizer Forms 120
+ Eccentric Piston Ring 299
+ Economy, Factors Governing 64
+ Efficiency, Actual Heat 62
+ Efficiency, Maximum Theoretical 61
+ Efficiency, Mechanical 62
+ Efficiency of Internal Combustion Engine 60
+ Efficiency, Various Measures of 61
+ Eight-cylinder Engine 95
+ Eight-cylinder Timing Diagram 276
+ Electricity and Magnetism, Relation of 162
+ Electrical Ignition Best 156
+ Electric Starting Systems 569
+ Engine, Advantages of V Type 95
+ Engine Base Construction 319
+ Engine Bearings, Adjusting 443
+ Engine Bearings, Refitting 442
+ Engine Bed Timbers, Standard 330
+ Engine, Four-cycle, Action of 38
+ Engine, Four-cycle, Piston Movements in 40
+ Engine Functions, Duration of 93
+ Engine Ignition, Locating Troubles 353
+ Engine Installation, Gnome 344
+ Engine Installation, Anzani Radial 344
+ Engine Installation, Hall-Scott 332
+ Engine Installation, Rotary 342
+ Engine Operation, Sequence of 84
+ Engine Parts and Functions 80
+ Engine Starts Hard, Ignition Troubles Causing 369
+ Engine Stoppage, Causes of 347
+ Engine Temperatures 221
+ Engine Trouble Charts 369
+ Engine Troubles, Cooling 358
+ Engine Troubles, Hints For Locating 345
+ Engine Troubles, Ignition 353
+ Engine Troubles, Noisy Operation 359
+ Engine Troubles, Oiling 357
+ Engine Troubles Summarized 350
+ Engine, Two-cycle, Action of 41
+ Engines, Classification of 458
+ Engines, Cylinder Arrangement 31-32
+ Engines, Eight-cylinder V 95
+ Engines, Four-cylinder Forms 88
+ Engines, Graphic Comparison of 33-34-35
+ Engines, Internal Combustion, Types of 30
+ Engines, Multiple Cylinder, Power Delivery in 91
+ Engines, Multiple Cylinder, Why Best 83
+ Engines, Rotary Cylinder 107
+ Engines, Six-cylinder Forms 88
+ Engines, Twelve-cylinder 96
+ Equalizer, Crank-shaft 449
+ Exhaust Closing 270
+ Exhaust Valve Design, Early Gnome 475
+ Exhaust Valve Opening 270
+ Explosive Gases, Mixtures of 56
+ Explosive Motors, Inefficiency in 74
+ Explosive Motors, Why Best 27
+
+ F
+
+ Factors Governing Economy 64
+ Factors Limiting Compression 70
+ Faults in Ignition 352
+ Figuring Horse-power Needed 21
+ Files, Use and Care of 383
+ First Law of Gases 49
+ Fitting Bearings By Scraping 447
+ Fitting Brasses 450
+ Fitting Connecting Rods 449
+ Fitting Main Bearings 448
+ Fitting Piston Rings 439
+ Float Feed Carburetor Development 124
+ Float Feed Carburetors 122
+ Force Feed Oiling System 218
+ Forked Connecting Rods 310
+ Four-cycle Engine, Action of 38
+ Four-cycle Engine, Why Best 45
+ Fourteen-cylinder Engine 474
+ Four Valves Per Cylinder 284
+ Friction, Definition of 302
+ Fuel Feed By Gravity 116
+ Fuel Feed by Vacuum Tank 117
+ Fuel Storage and Supply 116
+ Fuel Strainers, Types of 141
+ Fuel Strainers, Utility of 140
+ Fuel System Faults 354
+ Fuel System Installation, Hall-Scott 336
+ Fuel System, Gnome 490
+ Fuel Utilization Chart 62
+
+ G
+
+ Gas Engine, Beau de Rocha's Principles 59
+ Gas Engine Development 28
+ Gas Engine, Early Forms of 48
+ Gas Engine, Inventors of 29
+ Gas Engine, Theory of 47
+ Gases, Compression of 49
+ Gases, First Law of 49
+ Gases, Second Law of 50
+ Gaskets, How to Use 452
+ Gasoline, Air Needed to Burn 113
+ Gas Engines, Parts of 80
+ Gas Vacuum Engine, Brown's 28
+ German Airplane Motors 543
+ German Gnome Type Engine 495
+ Gnome Aviation Engine, Early Form 472
+ Gnome Crank-shaft 483
+ Gnome Cylinder, Machining 489
+ Gnome Cylinder Retention 475
+ Gnome Engine, Fuel, Lubrication and Ignition 490
+ Gnome Engine, German Type 495
+ Gnome Engine Installation 344
+ Gnome Firing Order 482
+ Gnome Fourteen-cylinder, Engine 474
+ Gnome Fourteen-cylinder Engine Details 480
+ Gnome Monosoupape, How to Time 278
+ Gnome Monosoupape Type Engine 486
+ Graphic Comparison of Engine Types 33-34-35
+ Graphic Comparison, Two- and Four-cycle 46
+ Gravity Feed System 116
+ Grinding Valves 429
+
+ H
+
+ Hall-Scott Aviation Engines 539
+ Hall-Scott Engine Installation 332
+ Hall-Scott Engine, Preparations For Starting 341
+ Hall-Scott Engine Tools 410
+ Hall-Scott Lubrication System 211
+ Hall-Scott Statistic Sheet 544
+ Heat and Its Work 54
+ Heat in Gas Engine Cylinder 69
+ Heat Given to Cooling Water 78
+ Heat Loss, Causes of 74
+ Heat Loss in Airplane Engine 221
+ Heat Loss in Wall Cooling 65
+ High Altitude, How it Affects Power 144
+ High Tension Magneto 172
+ Hints For Locating Engine Troubles 345
+ Hints for Starting Engine 361
+ Hispano-Suiza Model A Engine 512
+ Horse-power Needed in Airplane 21
+ Horse-power Needed, How Figured 22
+ How An Engine is Timed 277
+
+ I
+
+ Ignition, Electric 156
+ Ignition, Elements of 157
+ Ignition of Gnome Engine 490
+ Ignition System, Battery 571
+ Ignition Systems, Early 155
+ Ignition System Faults 352
+ Ignition, Time of 273
+ Ignition, Two Spark 196
+ I Head Cylinders 248
+ Improvements in Gas Engines 29
+ Indicating Meters, Engine Speed 563
+ Indicating Meters, Oil and Air Pressure 563
+ Indicator Cards, How To Read 66
+ Indicator Cards, Value of 66
+ Individual Cylinder Castings 234
+ Induction Coil, Defects in 373
+ Inefficiency, Causes of 74
+ Inlet Valve Closing 272
+ Inlet Valve Opening 270
+ Installation, Airplane Engine 324
+ Installation, Curtiss OX-2 Engine 328
+ Installation, Hall-Scott Engine 332
+ Installation of Rotary Engines 342
+ Intake Manifold Construction 143
+ Intake Manifold Design 142
+ Internal Combustion Engine, Efficiency of 60, 62
+ Internal Combustion Engines, Main Types of 30
+ Inverted Engine Placing 325
+ Isothermal Diagram 51
+ Isothermal Law 48
+
+ K
+
+ Keeping Oil Out of Combustion Chamber 303
+ Knight Sleeve Valves 266
+
+ L
+
+ Lag and Lead, Explanation of 268
+ Lapping Crank-pins 445
+ Lead Given Exhaust Valve 270
+ Leak Proof Piston Rings 301
+ Lenoir Engine Action 48
+ Le Rhone Cams and Valve Actuation 500
+ Le Rhone Carburetor 501
+ Le Rhone Connecting Rod Assembly, Distinctive 498
+ Le Rhone Engine Action 503
+ Le Rhone Rotary Engine 495
+ L Head Cylinders 248
+ Liquid Fuels, Properties of 110
+ Locating Carburetor Troubles 354
+ Locating Engine Troubles 350
+ Locating Ignition Troubles 353
+ Locating Oiling Troubles 357
+ Location of Magneto Trouble 181
+ Losses in Wall Cooling 65
+ Lost Power and Overheating, Summary of Troubles Causing 363
+ Lubricants, Derivation of 204
+ Lubricants, Requirements of 204
+ Lubricating System Classification 208
+ Lubricating Systems, Selection of 208
+ Lubrication By Constant Level Splash System 215
+ Lubrication By Dry Crank-case Method 218
+ Lubrication By Force Feed Best 218
+ Lubrication of Magneto 180
+ Lubrication System, Gnome 490
+ Lubrication System, Hall-Scott 211
+ Lubrication System, Thomas-Morse 210
+ Lubrication, Theory of 202
+ Lubrication, Why Necessary 201
+
+ M
+
+ Magnetic Circuits 161
+ Magnetic Influence Defined 158
+ Magnetic Lines of Force 161
+ Magnetic Substances 158
+ Magnetism, Flow Through Armature 166
+ Magnetism, Fundamentals of 157
+ Magnetism, Relation to Electricity 162
+ Magneto, Action of High Tension 173
+ Magneto Armature Windings 168
+ Magneto, Basic Principles of 163
+ Magneto, Berling 174
+ Magneto, Defects in 372
+ Magneto Distributor, Cleaning 180
+ Magneto Ignition Systems 169
+ Magneto Ignition Wiring 179
+ Magneto Interrupter, Adjustment of 180
+ Magneto, Low Voltage 168
+ Magneto, Lubrication of 180
+ Magneto Maintenance 180
+ Magneto, Method of Driving 175
+ Magneto Parts and Functions 167
+ Magneto, The Dixie 184
+ Magneto Timing 179
+ Magneto, Timing Dixie 188
+ Magneto, Transformer System 171
+ Magneto Trouble, Location of 181
+ Magneto, True High Tension 172
+ Magneto, Two Spark Dual 177
+ Magnets, Forms of 160
+ Magnets, How Produced 162
+ Magnets, Properties of 159
+ Main Bearings, Fitting 448
+ Manifold, Intake 143
+ Master Multiple Jet Carburetor 133
+ Master Rod Construction 310
+ Maximum Theoretical Efficiency 61
+ Meaning of Piston Speed 241
+ Measures of Efficiency 61
+ Measuring Tools 397
+ Mechanical Efficiency 62
+ Mercedes Aviation Engine 543
+ Metering Pin Carburetor, Stewart 128
+ Micrometer Caliper, Beading 405
+ Micrometer Calipers, Types and Use 404
+ Mixture, Effect of Altitude on 153
+ Mixture, Proportions of 151
+ Mixture, Starvation of 149
+ Monosoupape Gnome Engine 486
+ Mother Bod, Gnome Engine 305
+ Motor Misfires, Carburetor Faults Causing 374
+ Motor Misfires, Ignition Troubles Causing 370
+ Motor Races, Carburetor Faults Causing 374
+ Motor Starts Hard, Carburetor Faults Causing 374
+ Motor Stops In Flight, Carburetor Faults 374
+ Motor Stops Without Warning, Ignition Troubles 370
+ Multiple Cylinder Engine, Why Best 83
+ Multiple Nozzle Vaporizers 129
+ Multiple Valve Advantages 286
+
+ N
+
+ Noisy Engine Operation, Causes of 359
+ Noisy Operation, Carburetor Faults Causing 374
+ Noisy Operation, Summary of Troubles Causing 365
+
+ O
+
+ Offset Cylinders, Reason for 243
+ Oil Bi-pass, Function of 213
+ Oil, Draining From Crank-case 214
+ Oil Grooves, Cutting 448
+ Oil Pressure in Hall-Scott System 214
+ Oil Pressure Relief Bi-pass 213
+ Oiling System Defects 357
+ Oils for Cylinder Lubrication 206
+ Oils for Hall-Scott Engine 215
+ Oils for Lubrication 204
+ Operating Principles of Engines 37
+ Oscillating Piston Pin 295
+ Otto Four-cycle Cards 67
+ Overhauling Aviation Engines 412
+ Overhead Cam-shaft Location 252
+ Overheating, Causes of 359
+
+ P
+
+ Panhard Concentric Valves 255
+ Petroleum, Distillates of 111
+ Piston, Differential 291
+ Piston Pin Retention 293
+ Piston Ring Construction 298
+ Piston Ring Joints 299
+ Piston Ring Manipulation 438
+ Piston Ring Troubles 437
+ Piston Rings, Compound 301
+ Piston Rings, Concentric 299
+ Piston Rings, Eccentric 299
+ Piston Rings, Fitting 439
+ Piston Rings, Leak Proof 301
+ Piston Rings, Replacing 441
+ Piston Speed in Airplane Engines 241
+ Piston Speed, Meaning of 241
+ Piston Troubles and Remedies 436
+ Pistons, Aluminum 296
+ Pistons, Details of 288
+ Pistons for Two-cycle Engines 289
+ Positive Valve Systems 283
+ Power, Affected by High Altitude 145
+ Power Delivery in Multiple Cylinder Engines 91
+ Power, How Obtained From Heat 58
+ Power Needed in Airplane Engines 21
+ Power Used in Airplanes 26
+ Precautions in Assembling Parts 452
+ Pressure Relief Fitting 213
+ Pressures and Temperatures 63
+ Principles of Carburetion 112
+ Principles of Magneto Action 163
+ Properties of Cylinder Oils 207
+ Properties of Liquid Fuels 110
+ Pump Circulation Systems 226
+ Pump Forms 226
+
+ R
+
+ Radial Cylinder Arrangement 103
+ Reading Indicator Cards 67
+ Reamers, Types and Use 392
+ Reassembling Parts, Precautions in 451
+ Removable Cylinder Head 239
+ Renault Air Cooled Engine 507
+ Renault Engine Details 508
+ Repairing Scored Cylinders 423
+ Requisites for Best Power Effect 59
+ Reseating and Truing Valves 426
+ Resistance, Influence of 22
+ Rotary Cylinder Engines 107
+ Rotary Engine, Le Rhone 495
+ Rotary Engines, Castor Oil for 211
+ Rotary Engines, Installing 342
+ Rotary Engines, Why Odd Number of Cylinders 109
+ Rotary Engines, Why Odd Number of Cylinders Is Used 482
+
+ S
+
+ S. A. E. Engine Bed Dimensions 330
+ Salmson Nine-cylinder Engine 470
+ Schebler Carburetor 125
+ Scissors Joint Rods 310
+ Scored Cylinders, Repairing 422
+ Scrapers, Types of Bearing 446
+ Scraping Bearings to Fit 447
+ Second Law of Gases 50
+ Sequence of Engine Operation 84
+ Six-cylinder Timing Diagram 275
+ Sixteen Valve Duesenberg Engine 525
+ Skipping or Irregular Operation, Causes of 367
+ Sliding Sleeve Valves 266
+ Spark Plug Air Gaps, Setting 197
+ Spark Plug, Design of 193
+ Spark Plug, Mica 194
+ Spark Plug, Porcelain 193
+ Spark Plugs, Defects in 371
+ Spark Plugs for Two Spark Ignition 197
+ Spark Plug, Special for Airplane Engine 199
+ Spark Plug, Standard S. A. E. 195
+ Spherical Combustion Chambers 76
+ Splash Lubrication 215
+ Split Pin Remover 384
+ Spraying Carburetors 120
+ Springless Valves 280
+ Springs, for Valves 263
+ Spring Winder 384
+ Sprung Cam-shaft, Testing 451
+ Stand for Supporting Engine 414
+ Starting Engine, Hints for 361
+ Starting Hall-Scott Engine 341
+ Starting System, Christensen 567
+ Starting Systems, Compressed Air 565
+ Starting Systems, Electric 569
+ Statistics, American Engines 546, 547
+ Statistic Sheet, Hall-Scott Engines 544
+ Statistics of Benz Engine 551
+ Steam Engine, Efficiency of 59
+ Steam Engine, Why Not Used 27
+ Steel Scale, Machinists' 399
+ Stewart Metering Pin Carburetor 128
+ Storage Battery, Defects in 372
+ Stroke and Bore Ratio 240
+ Sturtevant Model 5A Engine 515
+ Summary of Engine Types 30
+ Sunbeam Aviation Engines 588
+ Sunbeam Eighteen-Cylinder Engine 561
+
+ T
+
+ Tap and Die Sets 397
+ Taps for Thread Cutting 394
+ Tee Head Cylinders 247
+ Temperature Computations 52
+ Temperatures and Explosive Pressures 64
+ Temperatures and Pressures 63
+ Temperatures, Operating 221
+ Testing Bearing Parallelism 453
+ Testing Connecting Rod Alignment 454
+ Testing Fit of Bearings 446
+ Testing Sprung Cam-shaft 451
+ Theory of Gas Engine 47
+ Theory of Lubrication 203
+ Thermo-syphon Cooling System 227
+ Thomas-Morse Aviation Engine 521
+ Thomas-Morse Lubrication System 210
+ Thread Pitch Gauge 403
+ Time of Ignition 273
+ Timer, Defects in 373
+ Times of Explosion 56
+ Timing Dixie Magneto 188
+ Timing Gears, Effects of Wear 456
+ Timing Magneto 179
+ Timing Valves 267
+ Tool Outfits, Typical 408
+ Tools for Adjusting and Erecting 378
+ Tools for Bearing Work 445
+ Tools for Curtiss Engines 408
+ Tools for Grinding Valves 430
+ Tools for Hall-Scott Engines 410, 411
+ Tools for Measuring 397
+ Tools for Reseating Valves 426
+ Trouble in Carburetion System 355
+ Trouble, Location of Magneto 181
+ Troubles, Engine, How to Locate 345
+ Troubles, Ignition 353
+ Troubles in Oiling System 357
+ True High Tension Magneto 172
+ Twelve-Cylinder Engines 96
+ Two-and Four-Cycle Types, Comparison of 44
+ Two-Cycle Engine Action 41
+ Two-Cycle Three-Port Engine 43
+ Two-Cycle Two-Port Engine 42
+ Two-Spark Ignition 196
+ Two-Stage Carburetor 131
+ Types of Aircraft 17
+ Types of Internal Combustion Engines 30
+
+ V
+
+ Vacuum Fuel Feed, Stewart 119
+ Value of Compression 69
+ Value of Indicator Cards 66
+ Valve Actuation, Le Rhone 500
+ Valve Design and Construction 256
+ Valve-Grinding Processes 429
+ Valve-Lifting Cams 259
+ Valve-Lifting Plungers 260
+ Valve Location Practice 245
+ Valve Operating Means 252
+ Valve Operating System, Depreciation in 433
+ Valve Operation 258
+ Valve Removal and Inspection 424
+ Valve Seating, How to Test 432
+ Valve Springs 263
+ Valve Timing, Exhaust 270
+ Valve Timing, Gnome Monosoupape 278
+ Valve Timing, Intake 270
+ Valve Timing, Lag and Lead 269
+ Valve Timing Procedure 277
+ Valve Timing Practice 267
+ Valves, Electric Welded 258
+ Valves, Flat and Bevel Seat 257
+ Valves, Four per Cylinder 284
+ Valves, How Placed in Cylinder 247
+ Valves in Cages 249
+ Valves in Removable Heads 249
+ Valves, Materials Used for 258
+ Valves, Reseating 426
+ Vaporizer, Simple Forms of 120
+ V Engines, Cylinder Arrangement in 102
+ Vernier, How Used 401
+
+ W
+
+ Wall Cooling, Losses in 65
+ Water Cooling by Natural Circulation 227
+ Water Cooling System 224
+ Weight of Airplane Motors 21
+ Wiring, Defects in 373
+ Wiring Magneto Ignition System 179
+ Wisconsin Engines 531
+ Wrenches, Forms of 380
+ Wrist-pin Retention 293
+ Wrist-pin Retention Locks 295
+ Wrist-pin Wear and Remedy 442
+
+ Z
+
+ Zenith Carburetor, Action of 137
+ Zenith Duplex Carburetor, Troubles in 356
+ Zenith Carburetor Installation 139
+
+
+
+
+LIST OF ILLUSTRATIONS
+
+
+Frontispiece. Part Sectional View of Hall-Scott Airplane Motor, Showing
+Principal Parts.
+
+Fig. 1. Diagrams Illustrating Computations for Horse-Power Required for
+Airplane Flight.
+
+Fig. 2. Plate Showing Heavy, Slow Speed Internal Combustion Engines Used
+Only for Stationary Power in Large Installations Giving Weight to
+Horse-Power Ratio.
+
+Fig. 3. Various Forms of Internal Combustion Engines Showing Decrease in
+Weight to Horse-Power Ratio with Augmenting Speed of Rotation.
+
+Fig. 4. Internal Combustion Engine Types of Extremely Fine Construction
+and Refined Design, Showing Great Power Outputs for Very Small Weight, a
+Feature Very Much Desired in Airplane Power Plants.
+
+Fig. 5. Outlining First Two Strokes of Piston in Four-Cycle Engine.
+
+Fig. 6. Outlining Second Two Strokes of Piston in Four-Cycle Engine.
+
+Fig. 7. Sectional View of L Head Gasoline Engine Cylinder Showing Piston
+Movements During Four-Stroke Cycle.
+
+Fig. 8. Showing Two-port, Two-cycle Engine Operation.
+
+Fig. 9. Defining Three-port, Two-cycle Engine Action.
+
+Fig. 10. Diagrams Contrasting Action of Two- and Four-Cycle Cylinders on
+Exhaust and Intake Stroke.
+
+Fig. 11. Diagram Isothermal and Adiabatic Lines.
+
+Fig. 12. Graphic Diagram Showing Approximate Utilization of Fuel Burned
+in Internal-Combustion Engine.
+
+Fig. 13. Otto Four-Cycle Card.
+
+Fig. 14. Diesel Motor Card.
+
+Fig. 15. Diagram of Heat in the Gas Engine Cylinder.
+
+Fig. 16. Chart Showing Relation Between Compression Volume and Pressure.
+
+Fig. 17. The Thompson Indicator, an Instrument for Determining
+Compressions and Explosion Pressure Values and Recording Them on Chart.
+
+Fig. 18. Spherical Combustion Chamber.
+
+Fig. 19. Enlarged Combustion Chamber.
+
+Fig. 20. Mercedes Aviation Engine Cylinder Section Showing Approximately
+Spherical Combustion Chamber and Concave Piston Top.
+
+Fig. 21. Side Sectional View of Typical Airplane Engine, Showing Parts
+and Their Relation to Each Other. This Engine is an Aeromarine Design
+and Utilizes a Distinctive Concentric Valve Construction.
+
+Fig. 22. Diagrams Illustrating Sequence of Cycles in One- and
+Two-Cylinder Engines Showing More Uniform Turning Effort on Crank-Shaft
+with Two-Cylinder Motors.
+
+Fig. 23. Diagrams Demonstrating Clearly Advantages which Obtain when
+Multiple-Cylinder Motors are Used as Power Plants.
+
+Fig. 24. Showing Three Possible Though Unconventional Arrangements of
+Four-Cylinder Engines.
+
+Fig. 25. Diagrams Outlining Advantages of Multiple Cylinder Motors, and
+Why They Deliver Power More Evenly Than Single Cylinder Types.
+
+Fig. 26. Diagrams Showing Duration of Events for a Four-Stroke Cycle,
+Six-Cylinder Engine.
+
+Fig. 27. Diagram Showing Actual Duration of Different Strokes in
+Degrees.
+
+Fig. 28. Another Diagram to Facilitate Understanding Sequence of
+Functions in Six-Cylinder Engine.
+
+Fig. 29. Types of Eight-Cylinder Engines Showing the Advantage of the V
+Method of Cylinder Placing.
+
+Fig. 30. Curves Showing Torque of Various Engine Types Demonstrate
+Graphically Marked Advantage of the Eight-Cylinder Type.
+
+Fig. 31. Diagrams Showing How Increasing Number of Cylinders Makes for
+More Uniform Power Application.
+
+Fig. 32. How the Angle Between the Cylinders of an Eight- and
+Twelve-Cylinder V Motor Varies.
+
+Fig. 33. The Hall-Scott Four-Cylinder 100 Horse-Power Aviation Motor.
+
+Fig. 34. Two Views of the Duesenberg Sixteen Valve Four-Cylinder
+Aviation Motor.
+
+Fig. 35. The Hall-Scott Six-Cylinder Aviation Engine.
+
+Fig. 36. The Curtiss Eight-Cylinder, 200 Horse-Power Aviation Engine.
+
+Fig. 37. The Sturtevant Eight-Cylinder, High Speed Aviation Motor.
+
+Fig. 38. Anzani 40-50 Horse-Power Five-Cylinder Air Cooled Engine.
+
+Fig. 39. Unconventional Six-Cylinder Aircraft Motor of Masson Design.
+
+Fig. 40. The Gnome Fourteen-Cylinder Revolving Motor.
+
+Fig. 41. How Gravity Feed Fuel Tank May Be Mounted Back of Engine and
+Secure Short Fuel Line.
+
+Fig. 42. The Stewart Vacuum Fuel Feed Tank.
+
+Fig. 43. Marine-Type Mixing Valve, by which Gasoline is Sprayed into Air
+Stream Through Small Opening in Air-Valve Seat.
+
+Fig. 44. Tracing Evolution of Modern Spray Carburetor. A--Early Form
+Evolved by Maybach. B.--Phoenix-Daimler Modification of Maybach's
+Principle. C--Modern Concentric Float Automatic Compensating Carburetor.
+
+Fig. 45. New Model of Schebler Carburetor With Metering Valve and
+Extended Venturi. Note Mechanical Connection Between Air Valve and Fuel
+Regulating Needle.
+
+Fig. 46. The Claudel Carburetor.
+
+Fig. 47. The Stewart Metering Pin Carburetor.
+
+Fig. 48. The Ball and Ball Two-Stage Carburetor.
+
+Fig. 49. The Master Carburetor.
+
+Fig. 50. Sectional View of Master Carburetor Showing Parts.
+
+Fig. 51. Sectional View of Zenith Compound Nozzle Compensating
+Carburetor.
+
+Fig. 52. Diagrams Explaining Action of Baverey Compound Nozzle Used in
+Zenith Carburetor.
+
+Fig. 53. The Zenith Duplex Carburetor for Airplane Motors of the V Type.
+
+Fig. 54. Rear View of Curtiss OX-2 90 Horse-Power Airplane Motor Showing
+Carburetor Location and Hot Air Leads.
+
+Fig. 55. Types of Strainers Interposed Between Vaporizer and Gasoline
+Tank to Prevent Water or Dirt Passing Into Carbureting Device.
+
+Fig. 56. Chart Showing Diminution of Air Pressure as Altitude Increases.
+
+Fig. 57. Some Simple Experiments to Demonstrate Various Magnetic
+Phenomena and Clearly Outline Effects of Magnetism and Various Forms of
+Magnets.
+
+Fig. 58. Elementary Form of Magneto Showing Principal Parts Simplified
+to Make Method of Current Generation Clear.
+
+Fig. 59. Showing How Strength of Magnetic Influence and of the Currents
+Induced in the Windings of Armature Vary with the Rapidity of Changes of
+Flow.
+
+Fig. 60. Diagrams Explaining Action of Low Tension Transformer Coil and
+True High Tension Magneto Ignition Systems.
+
+Fig. 60A. Side Sectional View of Bosch High-Tension Magneto Shows
+Disposition of Parts. End Elevation Depicts Arrangement of Interruptor
+and Distributor Mechanism.
+
+Fig. 61. Berling Two-Spark Dual Ignition System.
+
+Fig. 62. Berling Double-Spark Independent System.
+
+Fig. 63. Type DD Berling High Tension Magneto.
+
+Fig. 64. Wiring Diagrams of Berling Magneto Ignition Systems.
+
+Fig. 65. The Berling Magneto Breaker Box Showing Contact Points
+Separated and Interruptor Lever on Cam.
+
+Fig. 66. The Dixie Model 60 for Six-Cylinder Airplane Engine Ignition.
+
+Fig. 67. Installation Dimensions of Dixie Model 60 Magneto.
+
+Fig. 68. The Rotating Elements of the Dixie Magneto.
+
+Fig. 69. Suggestions for Adjusting and Dismantling Dixie Magneto.
+A--Screw Driver Adjusts Contact Points. B--Distributor Block Removed.
+C--Taking off Magnets. D--Showing How Easily Condenser and High Tension
+Windings are Removed.
+
+Fig. 69A. Sectional Views Outlining Construction of Dixie Magneto with
+Compound Distributor for Eight-Cylinder Engine Ignition.
+
+Fig. 70. Wiring Diagram of Dixie Magneto Installation on Hall-Scott
+Six-Cylinder 125 Horse-Power Aeronautic Motor.
+
+Fig. 71. How Magneto Ignition is Installed on Thomas-Morse 135
+Horse-Power Motor.
+
+Fig. 72. Spark-Plug Types Showing Construction and Arrangement of Parts.
+
+Fig. 73. Standard Airplane Engine Plug Suggested by S. A. E. Standards
+Committee.
+
+Fig. 74. Special Mica Plug for Aviation Engines.
+
+Fig. 75. Showing Use of Magnifying Glass to Demonstrate that Apparently
+Smooth Metal Surfaces May Have Minute Irregularities which Produce
+Friction.
+
+Fig. 76. Pressure Feed Oiling System of Thomas Aviation Engine Includes
+Oil Cooling Means.
+
+Fig. 77. Diagram of Oiling System, Hall-Scott Type A 125 Horse-Power
+Engine.
+
+Fig. 78. Sectional View of Typical Motor Showing Parts Needing
+Lubrication and Method of Applying Oil by Constant Level Splash System.
+Note also Water Jacket and Spaces for Water Circulation.
+
+Fig. 79. Pressure Feed Oil-Supply System of Airplane Power Plants has
+Many Good Features.
+
+Fig. 80. Why Pressure Feed System is Best for Eight-Cylinder Vee
+Airplane Engines.
+
+Fig. 81. Operating Temperatures of Automobile Engine Parts Useful as a
+Guide to Understand Airplane Power Plant Heat.
+
+Fig. 82. Water Cooling of Salmson Seven-Cylinder Radial Airplane Engine.
+
+Fig. 83. How Water Cooling System of Thomas Airplane Engine is Installed
+in Fuselage.
+
+Fig. 84. Finned Tube Radiators at the Side of Hall-Scott Airplane Power
+Plant Installed in Standard Fuselage.
+
+Fig. 85. Anzani Testing His Five-Cylinder Air Cooled Aviation Motor
+Installed in Bleriot Monoplane. Note Exposure of Flanged Cylinders to
+Propeller Slip Stream.
+
+Fig. 86. Views of Four-Cylinder Duesenberg Airplane Engine Cylinder
+Block.
+
+Fig. 87. Twin-Cylinder Block of Sturtevant Airplane Engine is Cast of
+Aluminum, and Has Removable Cylinder Head.
+
+Fig. 88. Aluminum Cylinder Pair Casting of Thomas 150 Horse-Power
+Airplane Engine is of the L Head Type.
+
+Fig. 90. Cross Section of Austro-Daimler Engine, Showing Offset Cylinder
+Construction. Note Applied Water Jacket and Peculiar Valve Action.
+
+Fig. 91. Diagrams Demonstrating Advantages of Offset Crank-Shaft
+Construction.
+
+Fig. 92. Diagram Showing Forms of Cylinder Demanded by Different Valve
+Placings. A--T Head Type, Valves on Opposite Sides. B--L Head Cylinder,
+Valves Side by Side. C--L Head Cylinder, One Valve in Head, Other in
+Pocket. D--Inlet Valve Over Exhaust Member, Both in Side Pocket.
+E--Valve-in-the-Head Type with Vertical Valves. F--Inclined Valves
+Placed to Open Directly into Combustion Chamber.
+
+Fig. 93. Sectional View of Engine Cylinder Showing Valve and Cage
+Installation.
+
+Fig. 94. Diagrams Showing How Gas Enters Cylinder Through Overhead
+Valves and Other Types. A--Tee Head Cylinder. B--L Head Cylinder.
+C--Overhead Valve.
+
+Fig. 95. Conventional Methods of Operating Internal Combustion Motor
+Valves.
+
+Fig. 96. Examples of Direct Valve Actuation by Overhead Cam-Shaft.
+A--Mercedes. B--Hall-Scott. C--Wisconsin.
+
+Fig. 97. CENSORED
+
+Fig. 98. CENSORED
+
+Fig. 99. Sectional Views Showing Arrangement of Novel Concentric Valve
+Arrangement Devised by Panhard for Aerial Engines.
+
+Fig. 100. Showing Clearance Allowed Between Valve Stem and Valve Stem
+Guide to Secure Free Action.
+
+Fig. 101. Forms of Valve-Lifting Cams Generally Employed. A--Cam Profile
+for Long Dwell and Quick Lift. B--Typical Inlet Cam Used with Mushroom
+Type Follower. C--Average Form of Cam. D--Designed to Give Quick Lift
+and Gradual Closing.
+
+Fig. 102. Showing Principal Types of Cam Followers which Have Received
+General Application.
+
+Fig. 103. Diagram Showing Proper Clearance to Allow Between Adjusting
+Screw and Valve Stems in Hall-Scott Aviation Engines.
+
+Fig. 104. Cam-Shaft of Thomas Airplane Motor Has Cams Forged Integral.
+Note Split Cam-Shaft Bearings and Method of Gear Retention.
+
+Fig. 105. Section Through Cylinder of Knight Motor, Showing Important
+Parts of Valve Motion.
+
+Fig. 106. Diagrams Showing Knight Sleeve Valve Action.
+
+Fig. 107. Cross Sectional View of Knight Type Eight Cylinder V Engine.
+
+Fig. 108. Diagrams Explaining Valve and Ignition Timing of Hall-Scott
+Aviation Engine.
+
+Fig. 109. Timing Diagram of Typical Six-Cylinder Engine.
+
+Fig. 110. Timing Diagram of Typical Eight-Cylinder V Engine.
+
+Fig. 111. Timing Diagram Showing Peculiar Valve Timing of Gnome
+"Monosoupape" Rotary Motor.
+
+Fig. 112. Two Methods of Operating Valves by Positive Cam Mechanism
+Which Closes as Well as Opens Them.
+
+Fig. 113. Diagram Comparing Two Large Valves and Four Small Ones of
+Practically the Same Area. Note How Easily Small Valves are Installed to
+Open Directly Into the Cylinder.
+
+Fig. 114. Sectional Views of Sixteen-Valve Four-Cylinder Automobile
+Racing Engine That May Have Possibilities for Aviation Service.
+
+Fig. 115. Front View of Curtiss OX-3 Aviation Motor, Showing
+Unconventional Valve Action by Concentric Push Rod and Pull Tube.
+
+Fig. 116. Forms of Pistons Commonly Employed in Gasoline Engines.
+A--Dome Head Piston and Three Packing Rings. B--Flat Top Form Almost
+Universally Used. C--Concave Piston Utilized in Knight Motors and Some
+Having Overhead Valves. D--Two-Cycle Engine Member with Deflector Plate
+Cast Integrally. E--Differential of Two-Diameter Piston Used in Some
+Engines Operating on Two-Cycle Principle.
+
+Fig. 117. Typical Methods of Piston Pin Retention Generally Used in
+Engines of American Design. A--Single Set Screw and Lock Nut. B--Set
+Screw and Check Nut Fitting Groove in Wrist Pin. C, D--Two Locking
+Screws Passing Into Interior of Hollow Wrist Pin. E--Split Ring Holds
+Pin in Place. F--Use of Taper Expanding Plugs Outlined. G--Spring
+Pressed Plunger Type. H--Piston Pin Pinned to Connecting Rod. I--Wrist
+Pin Clamped in Connecting Rod Small End by Bolt.
+
+Fig. 118. Typical Piston and Connecting Rod Assembly.
+
+Fig. 119. Parts of Sturtevant Aviation Engine. A--Cylinder Head Showing
+Valves. B--Connecting Rod. C--Piston and Rings.
+
+Fig. 120. Aluminum Piston and Light But Strong Steel Connecting Rod and
+Wrist Pin of Thomas Aviation Engine.
+
+Fig. 121. Cast Iron Piston of "Monosoupape" Gnome Engine Installed On
+One of the Short Connecting Rods.
+
+Fig. 122. Types of Aluminum Pistons Used In Aviation Engines.
+
+Fig. 123. Types of Piston Rings and Ring Joints. A--Concentric Ring.
+B--Eccentrically Machined Form. C--Lap Joint Ring. D--Butt Joint, Seldom
+Used. E--Diagonal Cut Member, a Popular Form.
+
+Fig. 124. Diagrams Showing Advantages of Concentric Piston Rings.
+
+Fig. 125. Leak-Proof and Other Compound Piston Rings.
+
+Fig. 126. Sectional View of Engine Showing Means of Preventing Oil
+Leakage By Piston Rings.
+
+Fig. 127. Connecting Rod and Crank-Shaft Construction of Gnome
+"Monosoupape" Engine.
+
+Fig. 128. Connecting Rod Types Summarized. A--Single Connecting Rod Made
+in One Piece, Usually Fitted in Small Single-Cylinder Engines Having
+Built-Up Crank-Shafts. B--Marine Type, a Popular Form on Heavy Engines.
+C--Conventional Automobile Type, a Modified Marine Form. D--Type Having
+Hinged Lower Cap and Split Wrist Pin Bushing. E--Connecting Rod Having
+Diagonally Divided Big End. F--Ball-Bearing Rod. G--Sections Showing
+Structural Shapes Commonly Employed in Connecting Rod Construction.
+
+Fig. 129. Double Connecting Rod Assembly For Use On Single Crank-Pin of
+Vee Engine.
+
+Fig. 130. Another Type of Double Connecting Rod for Vee Engines.
+
+Fig. 131. Part Sectional View of Wisconsin Aviation Engine, Showing
+Four-Bearing Crank-Shaft, Overhead Cam-Shaft, and Method of Combining
+Cylinders in Pairs.
+
+Fig. 132. Part Sectional View of Renault Twelve-Cylinder Water-Cooled
+Engine, Showing Connecting Rod Construction and Other Important Internal
+Parts.
+
+Fig. 133. Typical Cam-Shaft, with Valve Lifting Cams and Gears to
+Operate Auxiliary Devices Forged Integrally.
+
+Fig. 134. Important Parts of Duesenberg Aviation Engine. A--Three Main
+Bearing Crank-Shaft. B--Cam-Shaft with Integral Cams. C--Piston and
+Connecting Rod Assembly. D--Valve Rocker Group. E--Piston. F--Main
+Bearing Brasses.
+
+Fig. 135. Showing Method of Making Crank-Shaft. A--The Rough Steel
+Forging Before Machining. B--The Finished Six-Throw, Seven-Bearing
+Crank-Shaft.
+
+Fig. 136. Showing Form of Crank-Shaft for Twin-Cylinder Opposed Power
+Plant.
+
+Fig. 137. Crank-Shaft of Thomas-Morse Eight-Cylinder Vee Engine.
+
+Fig. 138. Crank-Case and Crank-Shaft Construction for Twelve-Cylinder
+Motors. A--Duesenberg. B--Curtiss.
+
+Fig. 139. Counterbalanced Crank-Shafts Reduce Engine Vibration and
+Permit of Higher Rotative Speeds.
+
+Fig. 140. View of Thomas 135 Horse-Power Aeromotor, Model 8, Showing
+Conventional Method of Crank-Case Construction.
+
+Fig. 141. Views of Upper Half of Thomas Aeromotor Crank-Case.
+
+Fig. 142. Method of Constructing Eight-Cylinder Vee Engine, Possible if
+Aluminum Cylinder and Crank-Case Castings are Used.
+
+Fig. 143. Simple and Compact Crank-Case, Possible When Radial Cylinder
+Engine Design is Followed.
+
+Fig. 144. Unconventional Mounting of German Inverted Cylinder Motor.
+
+Fig. 145. How Curtiss Model OX-2 Motor is Installed in Fuselage of
+Curtiss Tractor Biplane. Note Similarity of Mounting to Automobile Power
+Plant.
+
+Fig. 146. Latest Model of Curtiss JN-4 Training Machine, Showing
+Thorough Enclosure of Power Plant and Method of Disposing of the Exhaust
+Gases.
+
+Fig. 147. Front View of L. W. F. Tractor Biplane Fuselage, Showing
+Method of Installing Thomas Aeromotor and Method of Disposing of Exhaust
+Gases.
+
+Fig. 148. End Elevation of Hall-Scott A-7 Four-Cylinder Motor, with
+Installation Dimensions.
+
+Fig. 149. Plan and Side Elevation of Hall-Scott A-7 Four-Cylinder
+Airplane Engine, with Installation Dimensions.
+
+Fig. 150. CENSORED
+
+Fig. 151. CENSORED
+
+Fig. 152. CENSORED
+
+Fig. 153. Plan View of Hall-Scott Type A-5 125 Horse-Power Airplane
+Engine, Showing Installation Dimensions.
+
+Fig. 154. Three-Quarter View of Hall-Scott Type A-5 125 Horse-Power
+Six-Cylinder Engine, with One of the Side Radiators Removed to Show
+Installation in Standard Fuselage.
+
+Fig. 155. Diagram Showing Proper Installation of Hall-Scott Type A-5 125
+Horse-Power Engine with Pressure Feed Fuel Supply System.
+
+Fig. 156. Diagram Defining Installation of Gnome "Monosoupape" Motor in
+Tractor Biplane. Note Necessary Piping for Fuel, Oil, and Air Lines.
+
+Fig. 157. Showing Two Methods of Placing Propeller on Gnome Rotary
+Motor.
+
+Fig. 158. How Gnome Rotary Motor May Be Attached to Airplane Fuselage
+Members.
+
+Fig. 159. How Anzani Ten-Cylinder Radial Engine is Installed to Plate
+Securely Attached to Front End of Tractor Airplane Fuselage.
+
+Fig. 160. Side Elevation of Thomas 135 Horse-Power Airplane Engine,
+Giving Important Dimensions.
+
+Fig. 161. Front Elevation of Thomas-Morse 135 Horse-Power Aeromotor,
+Showing Main Dimensions.
+
+Fig. 162. Front and Side Elevations of Sturtevant Airplane Engine,
+Giving Principal Dimensions to Facilitate Installation.
+
+Fig. 163. Practical Hand Tools Useful in Dismantling and Repairing
+Airplane Engines.
+
+Fig. 164. Wrenches are Offered in Many Forms.
+
+Fig. 165. Illustrating Use and Care of Files.
+
+Fig. 166. Outlining Use of Cotter Pin Pliers, Spring Winder, and Showing
+Practical Outfit of Chisels.
+
+Fig. 167. Forms of Hand Operated Drilling Machines.
+
+Fig. 168. Forms of Drills Used in Hand and Power Drilling Machines.
+
+Fig. 169. Useful Set of Number Drills, Showing Stand for Keeping These
+in an Orderly Manner.
+
+Fig. 170. Illustrating Standard Forms of Hand and Machine Reamers.
+
+Fig. 171. Tools for Thread Cutting.
+
+Fig. 172. Showing Holder Designs for One- and Two-Piece Thread Cutting
+Dies.
+
+Fig. 173. Useful Outfit of Taps and Dies for the Engine Repair Shop.
+
+Fig. 174. Common Forms of Inside and Outside Calipers.
+
+Fig. 175. Measuring Appliances for the Machinist and Floor Man.
+
+Fig. 176. At Left, Special Form of Vernier Caliper for Measuring Gear
+Teeth; at Right, Micrometer for Accurate Internal Measurements.
+
+Fig. 177. Measuring Appliances of Value in Airplane Repair Work.
+
+Fig. 178. Standard Forms of Micrometer Caliper for External
+Measurements.
+
+Fig. 179. Special Tools for Maintaining Curtiss OX-2 Motor Used in
+Curtiss JN-4 Training Biplane.
+
+Fig. 180. Special Tools and Appliances to Facilitate Overhauling Work on
+Hall-Scott Airplane Engines.
+
+Fig. 181. Special Stand to Make Motor Overhauling Work Easier.
+
+Fig. 182. Showing Where Carbon Deposits Collect in Engine Combustion
+Chamber, and How to Burn Them Out with the Aid of Oxygen. A--Special
+Torch. B--Torch Coupled to Oxygen Tank. C--Torch in Use.
+
+Fig. 1821/2. Part Sectional View, Showing Valve Arrangement in Cylinder
+of Curtiss OX-2 Aviation Engine.
+
+Fig. 183. Tools for Restoring Valve Head and Seats.
+
+Fig. 184. Tools and Processes Utilized in Valve Grinding.
+
+Fig. 185. Outlining Points in Valve Operating Mechanism Where
+Depreciation is Apt to Exist.
+
+Fig. 186. Method of Removing Piston Rings, and Simple Clamp to
+Facilitate Insertion of Rings in Cylinder.
+
+Fig. 187. Tools and Processes Used in Refitting Engine Bearings.
+
+Fig. 188. Showing Points to Observe When Fitting Connecting Rod Brasses.
+
+Fig. 189. Methods of Testing to Insure Parallelism of Bearings After
+Fitting.
+
+Fig. 190. Views Outlining Construction of Three-Cylinder Anzani Aviation
+Motor.
+
+Fig. 190a. Illustrations Depicting Wrong and Right Methods of "Swinging
+the Stick" to Start Airplane Engine. At Top, Poor Position to Get Full
+Throw and Get Out of the Way. Below, Correct Position to Get Quick Turn
+Over of Crank-Shaft and Spring Away from Propeller.
+
+Fig. 191. The Anzani Six-Cylinder Water-Cooled Aviation Engine.
+
+Fig. 192. Sectional View of Anzani Six-Cylinder Water-Cooled Aviation
+Engine.
+
+Fig. 193. Three-Cylinder Anzani Air-Cooled Y-Form Engine.
+
+Fig. 194. Anzani Fixed Crank-Case Engine of the Six-Cylinder Form
+Utilizes Air Cooling Successfully.
+
+Fig. 195. Sectional View Showing Internal Parts of Six-Cylinder Anzani
+Engine, with Starwise Disposition of Cylinders.
+
+Fig. 196. The Anzani Ten-Cylinder Aviation Engine at the Left, and the
+Twenty-Cylinder Fixed Type at the Right.
+
+Fig. 197. Application of R. E. P. Five-Cylinder Fan-Shape Air-Cooled
+Motor to Early Monoplane.
+
+Fig. 198. The Canton and Unne Nine-Cylinder Water-Cooled Radial Engine.
+
+Fig. 199. Sectional View Showing Construction of Canton and Unne
+Water-Cooled Radial Cylinder Engine.
+
+Fig. 200. Sectional View Outlining Construction of Early Type Gnome
+Valve-in-Piston Type Motor.
+
+Fig. 201. Sectional View of Early Type Gnome Cylinder and Piston Showing
+Construction and Application of Inlet and Exhaust Valves.
+
+Fig. 202. Details of Old Style Gnome Motor Inlet and Exhaust Valve
+Construction and Operation.
+
+Fig. 203. The Gnome Fourteen-Cylinder 100 Horse-Power Aviation Engine.
+
+Fig. 204. Cam and Cam-Gear Case of the Gnome Seven-Cylinder Revolving
+Engine.
+
+Fig. 205. Diagrams Showing Why An Odd Number of Cylinders is Best for
+Rotary Cylinder Motors.
+
+Fig. 206. Simple Carburetor Used On Early Gnome Engines Attached to
+Fixed Crank-Shaft End.
+
+Fig. 207. Sectional Views of the Gnome Oil Pump.
+
+Fig. 208. Simplified Diagram Showing Gnome Motor Magneto Ignition
+System.
+
+Fig. 209. The G. V. Gnome "Monosoupape" Nine-Cylinder Rotary Engine
+Mounted on Testing Stand.
+
+Fig. 210. Sectional View Showing Construction of General Vehicle Co.
+"Monosoupape" Gnome Engine.
+
+Fig. 211. How a Gnome Cylinder is Reduced from Solid Chunk of Steel
+Weighing 97 Pounds to Finished Cylinder Weighing 51/2 Pounds.
+
+Fig. 212. The Gnome Engine Cam-Gear Case, a Fine Example of Accurate
+Machine Work.
+
+Fig. 213. G. V. Gnome "Monosoupape," with Cam-Case Cover Removed to Show
+Cams and Valve-Operating Plungers with Roller Cam Followers.
+
+Fig. 214. The 50 Horse-Power Rotary Bayerischen Motoren Gesellschaft
+Engine, a German Adaptation of the Early Gnome Design.
+
+Fig. 215. Nine-Cylinder Revolving Le Rhone Type Aviation Engine.
+
+Fig. 216. Part Sectional Views of Le Rhone Rotary Cylinder Engine,
+Showing Method of Cylinder Retention, Valve Operation and Novel Crank
+Disc Assembly.
+
+Fig. 217. Side Sectional View of Le Rhone Aviation Engine.
+
+Fig. 218. View Showing Le Rhone Valve Action and Connecting Rod Big End
+Arrangement.
+
+Fig. 219. Diagrams Showing Important Components of Le Rhone Motor.
+
+Fig. 220. How the Cams of the Le Rhone Motor Can Operate Two Valves with
+a Single Push Rod.
+
+Fig. 221. The Le Rhone Carburetor at A and Fuel Supply Regulating Device
+at B.
+
+Fig. 222. Diagrams Showing Le Rhone Motor Action and Firing Order.
+
+Fig. 223. Diagram Showing Positions of Piston in Le Rhone Rotary
+Cylinder Motor.
+
+Fig. 224. Diagrams Showing Valve Timing of Le Rhone Aviation Engine.
+
+Fig. 225. Diagrams Showing How Cylinder Cooling is Effected in Renault
+Vee Engines.
+
+Fig. 226. End Sectional View of Renault Air-Cooled Aviation Engine.
+
+Fig. 227. Side Sectional View of Renault Twelve-Cylinder Air-Cooled
+Aviation Engine Crank-Case, Showing Use of Plain and Ball Bearings for
+Crank-Shaft Support.
+
+Fig. 228. End View of Renault Twelve-Cylinder Engine Crank-Case, Showing
+Magneto Mounting.
+
+Fig. 229. Diagram Outlining Renault Twelve-Cylinder Engine Ignition
+System.
+
+Fig. 230. The Simplex Model A Hispano-Suiza Aviation Engine, a Very
+Successful Form.
+
+Fig. 231. The Curtiss OXX-5 Aviation Engine is an Eight-Cylinder Type
+Largely Used on Training Machines.
+
+Fig. 232. Top and Bottom Views of the Curtiss OXX-5 100 Horse-Power
+Aviation Engine.
+
+Fig. 233. End View of Thomas-Morse 150 Horse-Power Aluminum Cylinder
+Aviation Motor Having Detachable Cylinder Heads.
+
+Fig. 234. Side View of Thomas-Morse High Speed 150 Horse-Power Aviation
+Motor with Geared Down Propeller Drive.
+
+Fig. 235. The Reduction Gear-Case of Thomas-Morse 150 Horse-Power
+Aviation Motor, Showing Ball Bearing and Propeller Drive Shaft Gear.
+
+Fig. 236. The Six-Cylinder Aeromarine Engine.
+
+Fig. 237. The Wisconsin Aviation Engine, at Top, as Viewed from
+Carburetor Side. Below, the Exhaust Side.
+
+Fig. 238. Dimensioned End Elevation of Wisconsin Six Motor.
+
+Fig. 239. Dimensioned Side Elevation of Wisconsin Six Motor.
+
+Fig. 240. Power, Torque and Efficiency Curves of Wisconsin Aviation
+Motor.
+
+Fig. 241. Timing Diagram, Wisconsin Aviation Engine.
+
+Fig. 242. Dimensioned End View of Wisconsin Twelve-Cylinder Airplane
+Motor.
+
+Fig. 243. Dimensioned Side Elevation of Wisconsin Twelve-Cylinder
+Airplane Motor.
+
+Fig. 244. Side and End Sectional Views of Four-Cylinder Argus Engine, a
+German 100 Horse-Power Design Having Bore and Stroke of 140 mm., or 5.60
+inches, and Developing Its Power at 1,368 R.P.M. Weight, 350 Pounds.
+
+Fig. 245. Part Sectional View of 90 Horse-Power Mercedes Engine, Which
+is Typical of the Design of Larger Sizes.
+
+Fig. 246. Part Sectional Side View and Sectional End View of Benz 160
+Horse-Power Aviation Engine.
+
+Fig. 247. At Top, the Sunbeam Overhead Valve 170 Horse-Power
+Six-Cylinder Engine. Below, Side View of Sunbeam 350 Horse-Power
+Twelve-Cylinder Vee Engine.
+
+Fig. 248. Side View of Eighteen-Cylinder Sunbeam Coatalen Aircraft
+Engine Rated at 475 B.H.P.
+
+Fig. 249. Sunbeam Eighteen-Cylinder Motor, Viewed from Pump and Magneto
+End.
+
+Fig. 250. Propeller End of Sunbeam Eighteen-Cylinder 475 B.H.P. Aviation
+Engine.
+
+Fig. 251. View of Airplane Cowl Board, Showing the Various Navigating
+and Indicating Instruments to Aid the Aviator in Flight.
+
+Fig. 252. Parts of Christensen Air Starting System Shown at A, and
+Application of Piping and Check Valves to Cylinders of Thomas-Morse
+Aeromotor Outlined at B.
+
+Fig. 253. Diagrams Showing Installation of Air Starting System on
+Thomas-Morse Aviation Motor.
+
+
+
+
+ CATALOGUE
+ _Of the_ LATEST _and_ BEST
+ PRACTICAL _and_ MECHANICAL
+ BOOKS
+
+ _Including Automobile and Aviation Books_
+
+ [Illustration]
+
+
+ _Any of these books will be sent prepaid to any part of the world, on
+ receipt of price. Remit by Draft, Postal Order, Express Order or
+ Registered Letter_
+
+
+ Published and For Sale By
+ The Norman W. Henley Publishing Co.,
+ 2 West 45th Street, New York, U.S.A.
+
+
+
+
+ INDEX
+
+ PAGES
+ Air Brakes 21, 24
+ Arithmetic 14, 25, 31
+ Automobile Books 3, 4, 5, 6
+ Automobile Charts 6, 7
+ Automobile Ignition Systems 5
+ Automobile Lighting 5
+ Automobile Questions and Answers 4
+ Automobile Repairing 4
+ Automobile Starting Systems 5
+ Automobile Trouble Charts 5, 6
+ Automobile Welding 5
+ Aviation 7
+ Aviation Chart 7
+ Batteries, Storage 5
+ Bevel Gear 19
+ Boiler-Room Chart 9
+ Brazing 7
+ Cams 19
+ Carburetion Trouble Chart 6
+ Change Gear 19
+ Charts 6, 7, 8
+ Coal 22
+ Coke 9
+ Combustion 22
+ Compressed Air 10
+ Concrete 10, 11, 12
+ Concrete for Farm Use 11
+ Concrete for Shop Use 11
+ Cosmetics 27
+ Cyclecars 5
+ Dictionary 12
+ Dies 12, 13
+ Drawing 13, 14
+ Drawing for Plumbers 28
+ Drop Forging 13
+ Dynamo Building 14
+ Electric Bells 14
+ Electric Switchboards 14, 16
+ Electric Toy Making 15
+ Electric Wiring 14, 15, 16
+ Electricity 14, 15, 16, 17
+ Encyclopedia 24
+ E-T Air Brake 24
+ Every-day Engineering 34
+ Factory Management 17
+ Ford Automobile 3
+ Ford Trouble Chart 6
+ Formulas and Recipes 29
+ Fuel 17
+ Gas Construction 18
+ Gas Engines 18, 19
+ Gas Tractor 33
+ Gearing and Cams 19
+ Glossary of Aviation Terms 7, 12
+ Heating 31, 32
+ Horse-Power Chart 9
+ Hot-Water Heating 31, 32
+ House Wiring 15, 17
+ How to Run an Automobile 3
+ Hydraulics 5
+ Ice and Refrigeration 20
+ Ignition Systems 5
+ Ignition-Trouble Chart 6
+ India Rubber 30
+ Interchangeable Manufacturing 24
+ Inventions 20
+ Knots 20
+ Lathe Work 20
+ Link Motions 22
+ Liquid Air 21
+ Locomotive Boilers 22
+ Locomotive Breakdowns 22
+ Locomotive Engineering 21, 22, 23, 24
+ Machinist Book 24, 25, 26
+ Magazine, Mechanical 34
+ Manual Training 26
+ Marine Engineering 26
+ Marine Gasoline Engines 19
+ Mechanical Drawing 13, 14
+ Mechanical Magazine 34
+ Mechanical Movements 25
+ Metal Work 12, 13
+ Motorcycles 5, 6
+ Patents 20
+ Pattern Making 27
+ Perfumery 27
+ Perspective 13
+ Plumbing 28, 29
+ Producer Gas 19
+ Punches 13
+ Questions and Answers on Automobile 4
+ Questions on Heating 32
+ Railroad Accidents 23
+ Railroad Charts 9
+ Recipe Book 29
+ Refrigeration 20
+ Repairing Automobiles 4
+ Rope Work 20
+ Rubber 30
+ Rubber Stamps 30
+ Saw Filing 30
+ Saws, Management of 30
+ Sheet-Metal Works 12, 13
+ Shop Construction 25
+ Shop Management 25
+ Shop Practice 25
+ Shop Tools 25
+ Sketching Paper 14
+ Soldering 7
+ Splices and Rope Work 20
+ Steam Engineering 30, 31
+ Steam Heating 31, 32
+ Steel 32
+ Storage Batteries 5
+ Submarine Chart 9
+ Switchboards 14, 16
+ Tapers 21
+ Telegraphy, Wireless 17
+ Telephone 16
+ Thread Cutting 26
+ Tool Making 24
+ Toy Making 15
+ Train Rules 23
+ Tractive Power Chart 9
+ Tractor, Gas 33
+ Turbines 33
+ Vacuum Heating 32
+ Valve Setting 22
+ Ventilation 31
+ Watch Making 33
+ Waterproofing 12
+ Welding with Oxy-acetylene Flame 5, 33
+ Wireless Telegraphy 17
+ Wiring 14, 15
+ Wiring Diagrams 14
+
+
+Any of these books promptly sent prepaid to any address in the world on
+receipt of price.
+
+=HOW TO REMIT=--By Postal Money Order, Express Money Order, Bank Draft
+or Registered Letter.
+
+
+~AUTOMOBILES AND MOTORCYCLES~
+
+
+=The Modern Gasoline Automobile--Its Design, Construction, and
+Operation, 1918 Edition.= By VICTOR W. PAGE, M.S.A.E.
+
+ This is the most complete, practical and up-to-date treatise on
+ gasoline automobiles and their component parts ever published.
+ In the new _revised_ and _enlarged_ 1918 _edition_, all phases
+ of automobile construction, operation and maintenance are fully
+ and completely described, and in language anyone can understand.
+ Every part of all types of automobiles, from light cycle-cars to
+ heavy motor trucks and tractors, are described in a thorough
+ manner, not only the automobile, but every item of it;
+ equipment, accessories, tools needed, supplies and spare parts
+ necessary for its upkeep, are fully discussed.
+
+ _It is clearly and concisely written by an expert familiar with
+ every branch of the automobile industry and the originator of
+ the practical system of self-education on technical subjects. It
+ is a liberal education in the automobile art, useful to all who
+ motor for either business or pleasure._
+
+ Anyone reading the incomparable treatise is in touch with all
+ improvements that have been made in motor-car construction. All
+ latest developments, such as high speed aluminum motors and
+ multiple valve and sleeve-valve engines, are considered in
+ detail. The latest ignition, carburetor and lubrication practice
+ is outlined. New forms of change speed gears, and final power
+ transmission systems, and all latest chassis improvements are
+ shown and described. This book is used in all leading automobile
+ schools and is conceded to be the STANDARD TREATISE. The chapter
+ on Starting and Lighting Systems has been greatly enlarged, and
+ many automobile engineering features that have long puzzled
+ laymen are explained so clearly that the underlying principles
+ can be understood by anyone. This book was first published six
+ years ago and so much new matter has been added that it is
+ nearly twice, its original size. The only treatise covering
+ various forms of war automobiles and recent developments in
+ motor-truck design as well as pleasure cars. _This book is not
+ too technical for the layman nor too elementary for the more
+ expert. It is an incomparable work of reference, for home or
+ school_. 1,000 6x9 pages, nearly 1,000 illustrations, 12 folding
+ plates. Cloth bound. Price =$3.00=
+
+ WHAT IS SAID OF THIS BOOK:
+
+ "It is the best book on the Automobile seen up to date."--J. H.
+ Pile, Associate Editor _Automobile Trade Journal_.
+
+ "Every Automobile Owner has use for a book of this
+ character."--_The Tradesman_.
+
+ "This book is superior to any treatise heretofore published on
+ the subject."--_The Inventive Age_.
+
+ "We know of no other volume that is so complete in all its
+ departments, and in which the wide field of automobile
+ construction with its mechanical intricacies is so plainly
+ handled, both in the text and in the matter of
+ illustrations."--_The Motorist_.
+
+ "The book is very thorough, a careful examination failing to
+ disclose any point in connection with the automobile, its care
+ and repair, to have been overlooked."--_Iron Age_.
+
+ "Mr. Page has done a great work, and benefit to the Automobile
+ Field."--W. C. Hasford, Mgr. Y. M. C. A. Automobile School,
+ Boston, Mass.
+
+ "It is just the kind of a book a motorist needs if he wants to
+ understand his car."--_American Thresherman_.
+
+
+=The Model T Ford Car, Its Construction, Operation and Repair.= By
+VICTOR W. PAGE, M.S.A.E.
+
+ This is a complete instruction book. All parts of the Ford Model
+ T Car are described and illustrated; the construction is fully
+ described and operating principles made clear to everyone. Every
+ Ford owner needs this practical book. You don't have to guess
+ about the construction or where the trouble is, as it shows how
+ to take all parts apart and how to locate and fix all faults.
+ The writer, Mr. Page, has operated a Ford car for many years and
+ writes from actual knowledge. Among the contents are: 1. The
+ Ford Car: Its Parts and Their Functions. 2. The Engine and
+ Auxiliary Groups. How the Engine Works--The Fuel Supply
+ System--The Carburetor--Making the Ignition Spark--Cooling and
+ Lubrication. 3. Details of Chassis. Change Speed Gear--Power
+ Transmission--Differential Gear Action--Steering Gear--Front
+ Axle--Frame and Springs--Brakes. 4. How to Drive and Care for
+ the Ford. The Control System Explained--Starting the
+ Motor--Driving the Car--Locating Roadside Troubles--Tire
+ Repairs--Oiling the Chassis--Winter Care of Car. 5. Systematic
+ Location of Troubles and Remedies. Faults in Engine--Faults in
+ Carburetor--Ignition Troubles--Cooling and Lubrication System
+ Defects--Adjustment of Transmission Gear--General Chassis
+ Repairs. 95 illustrations, 300 pages, 2 large folding plates.
+ Price =$1.00=
+
+
+=How to Run an Automobile.= By VICTOR W. PAGE, M.S.A.E.
+
+ This treatise gives concise instructions for starting and
+ running all makes of gasoline automobiles, how to care for them,
+ and gives distinctive features of control. Describes every step
+ for shifting gears, controlling engines, etc. Among the chapters
+ contained are: I.--Automobile Parts and Their Functions.
+ II.--General Starting and Driving Instructions. III.--Typical
+ 1917 Control Systems. IV.--Care of Automobiles. 178 pages. 72
+ specially made illustrations. Price =$1.00=
+
+
+=Automobile Repairing Made Easy.= By VICTOR W. PAGE, M.S.A.E.
+
+ A comprehensive, practical exposition of every phase of modern
+ automobile repairing practice. Outlines every process incidental
+ to motor car restoration. Gives plans for workshop construction,
+ suggestions for equipment, power needed, machinery and tools
+ necessary to carry on business successfully. Tells how to
+ overhaul and repair all parts of all automobiles. Everything is
+ explained so simply that motorists and students can acquire a
+ full working knowledge of automobile repairing. This work starts
+ with the engine, then considers carburetion, ignition, cooling
+ and lubrication systems. The clutch, change speed gearing and
+ transmission system are considered in detail. Contains
+ instructions for repairing all types of axles, steering gears
+ and other chassis parts. Many tables, short cuts in figuring and
+ rules of practice are given for the mechanic. Explains fully
+ valve and magneto timing, "tuning" engines, systematic location
+ of trouble, repair of ball and roller bearings, shop kinks,
+ first aid to injured and a multitude of subjects of interest to
+ all in the garage and repair business. _This book contains
+ special instructions on electric starting_, _lighting and
+ ignition systems_, tire _repairing and rebuilding_, _autogenous
+ welding_, _brazing and soldering_, _heat treatment of steel_,
+ _latest timing practice_, _eight and twelve-cylinder motors_,
+ _etc._ 5-3/4x8. Cloth. 1,056 pages, 1,000 illustrations, 11
+ folding plates. Price =$3.00=
+
+ WHAT IS SAID OF THIS BOOK:
+
+ "'Automobile Repairing Made Easy' is the best book on the
+ subject I have ever seen and the only book I ever saw that is of
+ any value in a garage."--Fred Jeffrey, Martinsburg, Neb. "I wish
+ to thank you for sending me a copy of 'Automobile Repairing Made
+ Easy.' I do not think it could be excelled."--S. W. Gisriel,
+ Director of Instruction, Y. M. C. A., Philadelphia, Pa.
+
+
+=Questions and Answers Relating to Modern Automobile Construction,
+Driving and Repair.= By VICTOR W. PAGE, M.S.A.E.
+
+ A practical self-instructor for students, mechanics and
+ motorists, consisting of thirty-seven lessons in the form of
+ questions and answers, written with special reference to the
+ requirements of the non-technical reader desiring easily
+ understood, explanatory matter relating to all branches of
+ automobiling. The subject-matter is absolutely correct and
+ explained in simple language. If you can't answer all of the
+ following questions, you need this work. The answers to these
+ and over 2,000 more are to be found in its pages. Give the name
+ of all important parts of an automobile and describe their
+ functions. Describe action of latest types of kerosene
+ carburetors. What is the difference between a "double" ignition
+ system and a "dual" ignition system? Name parts of an induction
+ coil. How are valves timed? What is an electric motor starter
+ and how does it work? What are advantages of worm drive gearing?
+ Name all important types of ball and roller bearings. What is a
+ "three-quarter" floating axle? What is a two-speed axle? What is
+ the Vulcan electric gear shift? Name the causes of lost power in
+ automobiles. Describe all noises due to deranged mechanism and
+ give causes? How can you adjust a carburetor by the color of the
+ exhaust gases? What causes "popping" in the carburetor? What
+ tools and supplies are needed to equip a car? How do you drive
+ various makes of cars? What is a differential lock and where is
+ it used? Name different systems of wire wheel construction,
+ etc., etc. A popular work at a popular price. 5-1/4x7-1/2.
+ Cloth. 650 pages, 350 illustrations, 3 folding plates. Price
+ =$1.50=
+
+ WHAT IS SAID OF THIS BOOK:
+
+ "If you own a car--get this book."--_The Glassworker_.
+
+ "Mr. Page has the faculty of making difficult subjects plain and
+ understandable."--_Bristol Press_.
+
+ "We can name no writer better qualified to prepare a book of
+ instruction on automobiles than Mr. Victor W.
+ Page."--_Scientific American_.
+
+ "The best automobile catechism that has appeared."--_Automobile
+ Topics_.
+
+ "There are few men, even with long experience, who will not find
+ this book useful. Great pains have been taken to make it
+ accurate. Special recommendation must be given to the
+ illustrations, which have been made specially for the work. Such
+ excellent books as this greatly assist in fully understanding
+ your automobile."--_Engineering News_.
+
+
+=The Automobilist's Pocket Companion and Expense Record.= Arranged by
+VICTOR W. PAGE, M.S.A.E.
+
+ This book is not only valuable as a convenient cost record but
+ contains much information of value to motorists. Includes a
+ condensed digest of auto laws of all States, a lubrication
+ schedule, hints for care of storage battery and care of tires,
+ location of road troubles, anti-freezing solutions, horse-power
+ table, driving hints and many useful tables and recipes of
+ interest to all motorists. Not a technical book in any sense of
+ the word, just a collection of practical facts in simple
+ language for the everyday motorist. Price =$1.00=
+
+
+=Modern Starting, Lighting and Ignition Systems.= By VICTOR W. PAGE,
+M.E.
+
+ This practical volume has been written with special reference to
+ the requirements of the non-technical reader desiring easily
+ understood, explanatory matter, relating to all types of
+ automobile ignition, starting and lighting systems. It can be
+ understood by anyone, even without electrical knowledge, because
+ elementary electrical principles are considered before any
+ attempt is made to discuss features of the various systems.
+ These basic principles are clearly stated and illustrated with
+ simple diagrams. _All the leading systems of starting, lighting
+ and ignition have been described and illustrated with the
+ co-operation of the experts employed by the manufacturers._
+ Wiring diagrams are shown in both technical and non-technical
+ forms. All symbols are fully explained. It is a comprehensive
+ review of modern starting and ignition system practice, and
+ includes a complete exposition of storage battery construction,
+ care and repair. All types of starting motors, generators,
+ magnetos, and all ignition or lighting system-units are fully
+ explained. _Every person in the automobile business needs this
+ volume._ Among some of the subjects treated are: I.--Elementary
+ Electricity; Current Production; Flow; Circuits; Measurements;
+ Definitions; Magnetism; Battery Action; Generator Action.
+ II.--Battery Ignition Systems. III.--Magneto Ignition Systems.
+ IV.--Elementary Exposition of Starting System Principles.
+ V.--Typical Starting and Lighting Systems; Practical
+ Application; Wiring Diagrams; Auto-lite, Bijur, Delco,
+ Dyneto-Entz, Gray and Davis, Remy, U. S. L., Westinghouse,
+ Bosch-Rushmore, Genemotor, North-East, etc. VI.--Locating and
+ Repairing Troubles in Starting and Lighting Systems.
+ VII.--Auxiliary. Electric Systems; Gear-shifting by Electricity;
+ Warning Signals; Electric Brake; Entz-Transmission, Wagner-Saxon
+ Circuits, Wagner-Studebaker Circuits. 5-1/4x7-1/2. Cloth. 530
+ pages, 297 illustrations, 3 folding plates. Price =$1.50=
+
+
+=Automobile Welding With the Oxy-Acetylene Flame.= By M. KEITH DUNHAM.
+
+ This is the only complete book on the "why" and "how" of Welding
+ with the Oxy-Acetylene Flame, and from its pages one can gain
+ information so that he can weld anything that comes along.
+
+ No one can afford to be without this concise book, as it first
+ explains the apparatus to be used, and then covers in detail the
+ actual welding of all automobile parts. The welding of aluminum,
+ cast iron, steel, copper, brass and malleable iron is clearly
+ explained, as well as the proper way to burn the carbon out of
+ the combustion head of the motor. Among the contents are:
+ Chapter I.--Apparatus Knowledge. Chapter II.--Shop Equipment and
+ Initial Procedure. Chapter III.--Cast Iron. Chapter
+ IV.--Aluminum. Chapter V.--Steel. Chapter VI.--Malleable Iron,
+ Copper, Brass, Bronze. Chapter VII.--Carbon Burning and other
+ Uses of Oxygen and Acetylene. Chapter VIII.--How to Figure Cost
+ of Welding. 167 pages, fully illustrated. Price =$1.00=
+
+
+=Storage Batteries Simplified.= By VICTOR W. PAGE, M.S.A.E.
+
+ A comprehensive treatise devoted entirely to secondary batteries
+ and their maintenance, repair and use.
+
+ This is the most up-to-date book on this subject. Describes
+ fully the Exide, Edison, Gould, Willard, U. S. L. and other
+ storage battery forms in the types best suited for automobile,
+ stationary and marine work. Nothing of importance has been
+ omitted that the reader should know about the practical
+ operation and care of storage batteries. No details have been
+ slighted. The instructions for charging and care have been made
+ as simple as possible. Brief Synopsis of Chapters: Chapter
+ I.--Storage Battery Development; Types of Storage Batteries;
+ Lead Plate Types; The Edison Cell. Chapter II.--Storage Battery
+ Construction; Plates and Girds; Plante Plates; Faure Plates;
+ Non-Lead Plates; Commercial Battery Designs. Chapter
+ III.--Charging Methods; Rectifiers; Converters; Rheostats; Rules
+ for Charging. Chapter IV.--Battery Repairs and Maintenance.
+ Chapter V.--Industrial Application of Storage Batteries;
+ Glossary of Storage Battery Terms. 208 Pages. Very Fully
+ Illustrated. Price =$1.50 net=.
+
+
+=Motorcycles, Side Cars and Cyclecars; their Construction, Management
+and Repair.= By VICTOR W. PAGE, M.S.A.E.
+
+ The only complete work published for the motorcyclist and
+ cyclecarist. Describes fully all leading types of machines,
+ their design, construction, maintenance, operation and repair.
+ This treatise outlines fully the operation of two- and
+ four-cycle power plants and all ignition, carburetion and
+ lubrication systems in detail. Describes all representative
+ types of free engine clutches, variable speed gears and power
+ transmission systems. Gives complete instructions for operating
+ and repairing all types. Considers fully electric self-starting
+ and lighting systems, all types of spring frames and spring
+ forks and shows leading control methods. For those desiring
+ technical information a complete series of tables and many
+ formulae to assist in designing are included. The work tells how
+ to figure power needed to climb grades, overcome air resistance
+ and attain high speeds. It shows how to select gear ratios for
+ various weights and powers, how to figure braking efficiency
+ required, gives sizes of belts and chains to transmit power
+ safely, and shows how to design sprockets, belt pulleys, etc.
+ This work also includes complete formulae for figuring
+ horse-power, shows how dynamometer tests are made, defines
+ relative efficiency of air and water-cooled engines, plain and
+ anti-friction bearings and many other data of a practical,
+ helpful, engineering nature. Remember that you get this
+ information in addition to the practical description and
+ instructions which alone are worth several times the price of
+ the book. 550 pages. 350 specially made illustrations, 5 folding
+ plates. Cloth. Price =$1.50=
+
+ WHAT IS SAID OF THIS BOOK:
+
+ "Here is a book that should be in the cycle repairer's
+ kit."--_American Blacksmith._
+
+ "The best way for any rider to thoroughly understand his
+ machine, is to get a copy of this book; it is worth many times
+ its price."--_Pacific Motorcyclist._
+
+
+~AUTOMOBILE AND MOTORCYCLE CHARTS~
+
+
+=Chart. Location of Gasoline Engine Troubles Made Easy--A Chart Showing
+Sectional View of Gasoline Engine.= Compiled by VICTOR W. PAGE, M.S.A.E.
+
+ It shows clearly all parts of a typical four-cylinder gasoline
+ engine of the four-cycle type.
+
+ It outlines distinctly all parts liable to give trouble and also
+ details the derangements apt to interfere with smooth engine
+ operation.
+
+ Valuable to students, motorists, mechanics, repairmen,
+ garagemen, automobile salesmen, chauffeurs, motorboat owners,
+ motor-truck and tractor drivers, aviators, motor-cyclists, and
+ all others who have to do with gasoline power plants.
+
+ It simplifies location of all engine troubles, and while it will
+ prove invaluable to the novice, it can be used to advantage by
+ the more expert. It should be on the walls of every public and
+ private garage, automobile repair shop, club house or school. It
+ can be carried in the automobile or pocket with ease, and will
+ insure against loss of time when engine trouble manifests
+ itself.
+
+ This sectional view of engine is a complete review of all motor
+ troubles. It is prepared by a practical motorist for all who
+ motor. More information for the money than ever before offered.
+ No details omitted. Size 25x38 inches. Securely mailed on
+ receipt of =25 Cents=
+
+
+=Chart. Location of Ford Engine Troubles Made Easy.= Compiled by VICTOR
+W. PAGE, M.S.A.E.
+
+ This shows clear sectional views depicting all portions of the
+ Ford power plant and auxiliary groups. It outlines clearly all
+ parts of the engine, fuel supply system, ignition group and
+ cooling system, that are apt to give trouble, detailing all
+ derangements that are liable to make an engine lose power, start
+ hard or work irregularly. This chart is valuable to students,
+ owners, and drivers, as it simplifies location of all engine
+ faults. Of great advantage as an instructor for the novice, it
+ can be used equally well by the more expert as a work of
+ reference and review. It can be carried in the tool-box or
+ pocket with ease and will save its cost in labor eliminated the
+ first time engine trouble manifests itself. Prepared with
+ special reference to the average man's needs and is a practical
+ review of all motor troubles because it is based on the actual
+ experience of an automobile engineer-mechanic with the mechanism
+ the chart describes. It enables the non-technical owner or
+ operator of a Ford car to locate engine derangements by
+ systematic search, guided by easily recognized symptoms instead
+ of by guesswork. It makes the average owner independent of the
+ roadside repair shop when touring. Must be seen to be
+ appreciated. Size 25x38 inches. Printed on heavy bond paper.
+ Price =25 cents=
+
+
+=Chart. Lubrication of the Motor Car Chassis.= Compiled by VICTOR W.
+PAGE, M.S.A.E.
+
+ This chart presents the plan view of a typical six-cylinder
+ chassis of standard design and all parts are clearly indicated
+ that demand oil, also the frequency with which they must be
+ lubricated and the kind of oil to use. A practical chart for all
+ interested in motor-car maintenance. Size 24x38 inches. Price
+ =25 cents=
+
+
+=Chart. Location of Carburetion Troubles Made Easy.= Compiled by VICTOR
+W. PAGE, M.S.A.E.
+
+ This chart shows all parts of a typical pressure feed fuel
+ supply system and gives causes of trouble, how to locate defects
+ and means of remedying them. Size 24x38 inches. Price =25 cents=
+
+
+=Chart. Location of Ignition System Troubles Made Easy.= Compiled by
+VICTOR W. PAGE, M.S.A.E.
+
+ In this diagram all parts of a typical double ignition system
+ using battery and magneto current are shown, and suggestions are
+ given for readily finding ignition troubles and eliminating them
+ when found. Size 24x38 inches. Price =25 cents=
+
+
+=Chart. Location of Cooling and Lubrication System Faults.= Compiled by
+VICTOR W. PAGE, M.S.A.E.
+
+ This composite diagram shows a typical automobile power plant
+ using pump circulated water-cooling system and the most popular
+ lubrication method. Gives suggestions for curing all overheating
+ and loss of power faults due to faulty action of the oiling or
+ cooling group. Size 24x38 inches. Price =25 cents=
+
+
+=Chart. Motorcycle Troubles Made Easy.= Compiled by VICTOR W PAGE,
+M.S.A.E.
+
+ A chart showing sectional view of a single-cylinder gasoline
+ engine. This chart simplifies location of all power-plant
+ troubles. A single-cylinder motor is shown for simplicity. It
+ outlines distinctly all parts liable to give trouble and also
+ details the derangements apt to interfere with smooth engine
+ operation. This chart will prove of value to all who have to do
+ with the operation, repair or sale of motorcycles. No details
+ omitted. Size 30x20 inches Price =25 cents=
+
+
+~AVIATION~
+
+
+=Aviation Engines, their Design, Construction, Operation and Repair.= By
+Lieut. VICTOR W. PAGE, Aviation Section, S.C.U.S.R.
+
+ A practical work containing valuable instructions for aviation
+ students, mechanicians, squadron engineering officers and all
+ interested in the construction and upkeep of airplane power
+ plants.
+
+ The rapidly increasing interest in the study of aviation, and
+ especially of the highly developed internal combustion engines
+ that make mechanical flight possible, has created a demand for a
+ text-book suitable for schools and home study that will clearly
+ and concisely explain the workings of the various aircraft
+ engines of foreign and domestic manufacture.
+
+ This treatise, written by a recognized authority on all of the
+ practical aspects of internal combustion engine construction,
+ maintenance and repair fills the need as no other book does.
+
+ The matter is logically arranged; all descriptive matter is
+ simply expressed and copiously illustrated so that anyone can
+ understand airplane engine operation and repair even if without
+ previous mechanical training. This work is invaluable for anyone
+ desiring to become an aviator or aviation mechanician.
+
+ The latest rotary types, such as the Gnome, Monosoupape, and Le
+ Rhone, are fully explained, as well as the recently developed
+ Vee and radial types. The subjects of carburetion, ignition,
+ cooling and lubrication also are covered in a thorough manner.
+ The chapters on repair and maintenance are distinctive and found
+ in no other book on this subject.
+
+ Invaluable to the student, mechanic and soldier wishing to enter
+ the aviation service.
+
+ Not a technical book, but a practical, easily understood work of
+ reference for all interested in aeronautical science. 576 octavo
+ pages. 253 specially made engravings. Price =$3.00 net=
+
+
+~GLOSSARY OF AVIATION TERMS~
+
+
+=Termes D'Aviation, English-French, French-English.= Compiled by Lieuts.
+VICTOR W. PAGE, A.S., S.C.U.S.R., and PAUL MONTARIOL of the French
+Flying Corps, on duty on Signal Corps Aviation School, Mineola, L. I.
+
+ A complete, well illustrated volume intended to facilitate
+ conversation between English-speaking and French aviators. A
+ very valuable book for all who are about to leave for duty
+ overseas.
+
+ Approved for publication by Major W. G. Kilner, S.C., U.S.C.O.
+ Signal Corps Aviation School. Hazelhurst Field, Mineola, L. I.
+
+ This book should be in every Aviator's and Mechanic's Kit for
+ ready reference. 128 pages. Fully illustrated with detailed
+ engravings. Price =$1.00=
+
+
+=Aviation Chart. Location of Airplane Power Plant Troubles Made Easy.=
+By Lieut. VICTOR W. PAGE, A.S., S.C.U.S.R.
+
+ A large chart outlining all parts of a typical airplane power
+ plant, showing the points where trouble is apt to occur and
+ suggesting remedies for the common defects. Intended especially
+ for Aviators and Aviation Mechanics on School and Field Duty.
+ Price =50 cents=
+
+
+~BRAZING AND SOLDERING~
+
+
+=Brazing and Soldering.= By JAMES F. HOBART.
+
+ The only book that shows you just how to handle any job of
+ brazing or soldering that comes along; it tells you what mixture
+ to use, how to make a furnace if you need one. Full of valuable
+ kinks. The fifth edition of this book has just been published,
+ and to it much new matter and a large number of tested formulae
+ for all kinds of solders and fluxes have been added.
+ Illustrated. Price =25 cents=
+
+
+~CHARTS~
+
+
+=Aviation Chart. Location of Airplane Power Plant Troubles Made Easy.=
+By Lieut. VICTOR W. PAGE, A.S., S.C.U.S.R.
+
+ A large chart outlining all parts of a typical airplane power
+ plant, showing the points where trouble is apt to occur and
+ suggesting remedies for the common defects. Intended especially
+ for Aviators and Aviation Mechanics on School and Field Duty.
+ Price =50 cents=
+
+
+=Gasoline Engine Troubles Made Easy--A Chart Showing Sectional View of
+Gasoline Engine.= Compiled by Lieut. VICTOR W. PAGE, A.S., S.C.U.S.R.
+
+ It shows clearly all parts of a typical four-cylinder gasoline
+ engine of the four-cycle type. It outlines distinctly all parts
+ liable to give trouble and also details the derangements apt to
+ interfere with smooth engine operation.
+
+ Valuable to students, motorists, mechanics, repairmen,
+ garagemen, automobile salesmen, chauffeurs, motor-boat owners,
+ motor-truck and tractor drivers, aviators, motor-cyclists, and
+ all others who have to do with gasoline power plants.
+
+ It simplifies location of all engine troubles, and while it will
+ prove invaluable to the novice, it can be used to advantage by
+ the more expert. It should be on the walls of every public and
+ private garage, automobile repair shop, club house or school. It
+ can be carried in the automobile or pocket with ease and will
+ insure against loss of time when engine trouble manifests
+ itself.
+
+ This sectional view of engine is a complete review of all motor
+ troubles. It is prepared by a practical motorist for all who
+ motor. No details omitted. Size 25x38 inches. Price =25 cents=
+
+
+=Lubrication of the Motor Car Chassis.=
+
+ This chart presents the plan view of a typical six-cylinder
+ chassis of standard design and all parts are clearly indicated
+ that demand oil, also the frequency with which they must be
+ lubricated and the kind of oil to use. A practical chart for all
+ interested in motor-car maintenance. Size 24x38 inches. Price
+ =25 cents=
+
+
+=Location of Carburetion Troubles Made Easy.=
+
+ This chart shows all parts of a typical pressure feed fuel
+ supply system and gives causes of trouble, how to locate defects
+ and means of remedying them. Size 24x38 inches. Price =25 cents=
+
+
+=Location of Ignition System Troubles Made Easy.=
+
+ In this chart all parts of a typical double ignition system
+ using battery and magneto current are shown and suggestions are
+ given for readily finding ignition troubles and eliminating them
+ when found. Size 24x38 inches. Price =25 cents=
+
+
+=Location of Cooling and Lubrication System Faults.=
+
+ This composite chart shows a typical automobile power plant
+ using pump circulated water-cooling system and the most popular
+ lubrication method. Gives suggestions for curing all overheating
+ and loss of power faults due to faulty action of the oiling or
+ cooling group. Size 24x38 inches. Price =25 Cents=
+
+
+=Motorcycle Troubles Made Easy--A Chart Showing Sectional View of
+Single-Cylinder Gasoline Engine.= Compiled by VICTOR W. PAGE, M.S.A.E.
+
+ This chart simplifies location of all power-plant troubles, and
+ will prove invaluable to all who have to do with the operation,
+ repair or sale of motorcycles. No details omitted. Size 25x38
+ inches. Price =25 cents=
+
+
+=Location of Ford Engine Troubles Made Easy.= Compiled by VICTOR W.
+PAGE, M.S.A.E.
+
+ This shows clear sectional views depicting all portions of the
+ Ford power plant and auxiliary groups. It outlines clearly all
+ parts of the engine, fuel supply system, ignition group and
+ cooling system, that are apt to give trouble, detailing all
+ derangements that are liable to make an engine lose power, start
+ hard or work irregularly. This chart is valuable to students,
+ owners, and drivers, as it simplifies location of all engine
+ faults. Of great advantage as an instructor for the novice, it
+ can be used equally well by the more expert as a work of
+ reference and review. It can be carried in the toolbox or pocket
+ with ease and will save its cost in labor eliminated the first
+ time engine trouble manifests itself. Prepared with special
+ reference to the average man's needs and is a practical review
+ of all motor troubles because it is based on the actual
+ experience of an automobile engineer-mechanic with the mechanism
+ the chart describes. It enables the non-technical owner or
+ operator of a Ford car to locate engine derangements by
+ systematic search, guided by easily recognized symptoms instead
+ of by guesswork. It makes the average owner independent of the
+ roadside repair shop when touring. Must be seen to be
+ appreciated. Size 25x38 inches. Printed on heavy bond paper.
+ Price =25 cents=
+
+=Modern Submarine Chart--with Two Hundred Parts Numbered and Named.=
+
+ A cross-section view, showing clearly and distinctly all the
+ interior of a Submarine of the latest type. You get more
+ information from this chart, about the construction and
+ operation of a Submarine, than in any other way. No details
+ omitted--everything is accurate and to scale. It is absolutely
+ correct in every detail, having been approved by Naval
+ Engineers. All the machinery and devices fitted in a modern
+ Submarine Boat are shown, and to make the engraving more readily
+ understood all the features are shown in operative form, with
+ Officers and Men in the act of performing the duties assigned to
+ them in service conditions. This CHART IS REALLY AN ENCYCLOPEDIA
+ OF A SUBMARINE. It is educational and worth many times its cost.
+ Mailed in a Tube for =25 Cents=
+
+
+=Box Car Chart.=
+
+ A chart showing the anatomy of a box car, having every part of
+ the car numbered and its proper name given in a reference list.
+ Price =25 Cents=
+
+
+=Gondola Car Chart.=
+
+ A chart showing the anatomy of a gondola car, having every part
+ of the car numbered and its proper reference name given in a
+ reference list. Price =25 Cents=
+
+
+=Passenger-Car Chart.=
+
+ A chart showing the anatomy of a passenger-car, having every
+ part of the car numbered and its proper name given in a
+ reference list =25 Cents=
+
+
+=Steel Hopper Bottom Coal Car.=
+
+ A chart showing the anatomy of a steel Hopper Bottom Coal Car,
+ having every part of the car numbered and its proper name given
+ in a reference list. Price =25 Cents=
+
+
+=Tractive Power Chart.=
+
+ A chart whereby you can find the tractive power or drawbar pull
+ of any locomotive without making a figure. Shows what cylinders
+ are equal, how driving wheels and steam pressure affect the
+ power. What sized engine you need to exert a given drawbar pull
+ or anything you desire in this line. Price =50 Cents=
+
+
+=Horse-Power Chart.=
+
+ Shows the horse-power of any stationary engine without
+ calculation. No matter what the cylinder diameter of stroke, the
+ steam pressure of cut-off, the revolutions, or whether
+ condensing or non-condensing, it's all there. Easy to use,
+ accurate, and saves time and calculations. Especially useful to
+ engineers and designers. Price =50 Cents=
+
+
+=Boiler Room Chart.= By GEO. L. FOWLER.
+
+ A chart--size 14x28 inches--showing in isometric perspective the
+ mechanisms belonging in a modern boiler room. The various parts
+ are shown broken or removed, so that the internal construction
+ is fully illustrated. Each part is given a reference number, and
+ these, with the corresponding name, are given in a glossary
+ printed at the sides. This chart is really a dictionary of the
+ boiler room--the names of more than 200 parts being given. Price
+ =25 Cents=
+
+
+~COKE~
+
+
+=Modern Coking Practice, Including Analysis of Materials and Products.=
+
+By J. E. CHRISTOPHER and T. H. BYROM.
+
+ This, the standard work on the subject, has just been revised.
+ It is a practical work for those engaged in Coke manufacture and
+ the recovery of By-products. Fully illustrated with folding
+ plates. It has been the aim of the authors, in preparing this
+ book, to produce one which shall be of use and benefit to those
+ who are associated with, or interested in, the modern
+ developments of the industry. Among the Chapters contained in
+ Volume I are: Introduction; Classification of Fuels; Impurities
+ of Coals; Coal Washing; Sampling and Valuation of Coals, etc.;
+ Power of Fuels; History of Coke Manufacture; Developments in the
+ Coke Oven Design; Recent Types of Coke Ovens; Mechanical
+ Appliances at Coke Ovens; Chemical and Physical Examination of
+ Coke. Volume II covers fully the subject of By-Products. Price,
+ per volume =$3.00 net=
+
+
+~COMPRESSED AIR~
+
+
+=Compressed Air in All Its Applications.= By GARDNER D. HISCOX.
+
+ This is the most complete book on the subject of Air that has
+ ever been issued, and its thirty-five chapters include about
+ every phase of the subject one can think of. It may be called an
+ encyclopedia of compressed air. It is written by an expert, who,
+ in its 665 pages, has dealt with the subject in a comprehensive
+ manner, no phase of it being omitted. Includes the physical
+ properties of air from a vacuum to its highest pressure, its
+ thermodynamics, compression, transmission and uses as a motive
+ power, in the Operation of Stationary and Portable Machinery, in
+ Mining, Air Tools, Air Lifts, Pumping of Water, Acids, and Oils;
+ the Air Blast for Cleaning and Painting the Sand Blast and its
+ Work, and the Numerous Appliances in which Compressed Air is a
+ Most Convenient and Economical Transmitter of Power for
+ Mechanical Work, Railway Propulsion, Refrigeration, and the
+ Various Uses to which Compressed Air has been applied. Includes
+ forty-four tables of the physical properties of air, its
+ compression, expansion, and volumes required for various kinds
+ of work, and a list of patents on compressed air from 1875 to
+ date. Over 500 illustrations, 5th Edition, revised and enlarged.
+
+ Cloth bound. Price =$5.00=
+
+ Half Morocco. Price =$6.50=
+
+
+~CONCRETE~
+
+
+=Concrete Workers' Reference Books. A Series of Popular Handbooks for
+Concrete Users.= Prepared by A. A. HOUGHTON =50 cents=
+
+ _The author, in preparing this Series, has not only treated on
+ the usual types of construction, but explains and illustrates
+ molds and systems that are not patented, but which are equal in
+ value and often superior to those restricted by patents. These
+ molds are very easily and cheaply constructed and embody
+ simplicity, rapidity of operation, and the most successful
+ results in the molded concrete. Each of these books is fully
+ illustrated, and the subjects are exhaustively treated in plain
+ English._
+
+
+=Concrete Wall Forms.= By A. A. HOUGHTON.
+
+ A new automatic wall clamp is illustrated with working drawings.
+ Other types of wall forms, clamps, separators, etc., are also
+ illustrated and explained. (No. 1 of Series) Price =50 cents=
+
+
+=Concrete Floors and Sidewalks.= By A. A. HOUGHTON.
+
+ The molds for molding squares, hexagonal and many other styles
+ of mosaic floor and sidewalk blocks are fully illustrated and
+ explained. (No. 2 of Series) Price =50 cents=
+
+
+=Practical Concrete Silo Construction.= By A. A. HOUGHTON.
+
+ Complete working drawings and specifications are given for
+ several styles of concrete silos, with illustrations of molds
+ for monolithic and block silos. The tables, data, and
+ information presented in this book are of the utmost value in
+ planning and constructing all forms of concrete silos. (No. 3 of
+ Series) Price =50 cents=
+
+
+=Molding Concrete Chimneys, Slate and Hoof Tiles.= By A. A. HOUGHTON.
+
+ The manufacture of all types of concrete slate and roof tile is
+ fully treated. Valuable data on all forms of reinforced concrete
+ roofs are contained within its pages. The construction of
+ concrete chimneys by block and monolithic systems is fully
+ illustrated and described. A number of ornamental designs of
+ chimney construction with molds are shown in this valuable
+ treatise. (No. 4 of Series.) Price =50 cents=
+
+
+=Molding and Curing Ornamental Concrete.= By A. A. HOUGHTON.
+
+ The proper proportions of cement and aggregates for various
+ finishes, also the method of thoroughly mixing and placing in
+ the molds, are fully treated. An exhaustive treatise on this
+ subject that every concrete worker will find of daily use and
+ value. (No. 5 of Series.) Price =50 cents=
+
+
+=Concrete Monuments, Mausoleums and Burial Vaults.= By A. A. HOUGHTON.
+
+ The molding of concrete monuments to imitate the most expensive
+ cut stone is explained in this treatise with working drawings of
+ easily built molds. Cutting inscriptions and designs are also
+ fully treated. (No. 6 of Series.) Price =50 cents=
+
+
+=Molding Concrete Bathtubs, Aquariums and Natatoriums.= By A. A.
+HOUGHTON.
+
+ Simple molds and instruction are given for molding many styles
+ of concrete bathtubs, swimming-pools, etc. These molds are
+ easily built and permit rapid and successful work. (No. 7 of
+ Series.) Price =50 cents=
+
+
+=Concrete Bridges, Culverts and Sewers.= By A. A. HOUGHTON.
+
+ A number of ornamental concrete bridges with illustrations of
+ molds are given. A collapsible center or core for bridges,
+ culverts and sewers is fully illustrated with detailed
+ instructions for building. (No. 8 of Series.) Price =50 cents=
+
+
+=Constructing Concrete Porches.= By A. A. HOUGHTON.
+
+ A number of designs with working drawings of molds are fully
+ explained so any one can easily construct different styles of
+ ornamental concrete porches without the purchase of expensive
+ molds. (No. 9 of Series.) Price =50 cents=
+
+
+=Molding Concrete Flower-Pots, Boxes, Jardinieres, Etc.= By A. A.
+HOUGHTON.
+
+ The molds for producing many original designs of flower-pots,
+ urns, flower-boxes, jardinieres, etc., are fully illustrated and
+ explained, so the worker can easily construct and operate same.
+ (No. 10 of Series.) Price =50 cents=
+
+
+=Molding Concrete Fountains and Lawn Ornaments.= By A. A. HOUGHTON.
+
+ The molding of a number of designs of lawn seats, curbing,
+ hitching posts, pergolas, sun dials and other forms of
+ ornamental concrete for the ornamentation of lawns and gardens,
+ is fully illustrated and described. (No. 11 of Series.) Price
+ =50 cents=
+
+
+=Concrete from Sand Molds.= By A. A. HOUGHTON.
+
+ A Practical Work treating on a process which has heretofore been
+ held as a trade secret by the few who possessed it, and which
+ will successfully mold every and any class of ornamental
+ concrete work. The process of molding concrete with sand molds
+ is of the utmost practical value, possessing the manifold
+ advantages of a low cost of molds, the ease and rapidity of
+ operation, perfect details to all ornamental designs, density
+ and increased strength of the concrete, perfect curing of the
+ work without attention and the easy removal of the molds
+ regardless of any undercutting the design may have. 192 pages.
+ Fully illustrated Price =$2.00=
+
+
+=Ornamental Concrete without Molds.= By A. A. HOUGHTON.
+
+ The process for making ornamental concrete without molds has
+ long been held as a secret, and now, for the first time, this
+ process is given to the public. The book reveals the secret and
+ is the only book published which explains a simple, practical
+ method whereby the concrete worker is enabled, by employing wood
+ and metal templates of different designs, to mold or model in
+ concrete any Cornice, Archivolt, Column, Pedestal, Base Cap, Urn
+ or Pier in a monolithic form--right upon the job. These may be
+ molded in units or blocks and then built up to suit the
+ specifications demanded. This work is fully illustrated, with
+ detailed engravings. Price =$2.00=
+
+
+=Concrete for the Farm and in the Shop.= By H. COLIN CAMPBELL, C.E.,
+E.M.
+
+ "Concrete for the Farm and in the Shop" is a new book from cover
+ to cover, illustrating and describing in plain, simple language
+ many of the numerous applications of concrete within the range
+ of the home worker. Among the subjects treated are: Principles
+ of Reinforcing; Methods of Protecting Concrete so as to Insure
+ Proper Hardening; Home-made Mixers; Mixing by Hand and Machine;
+ Form Construction, Described and Illustrated by Drawings and
+ Photographs; Construction of Concrete Walls and Fences; Concrete
+ Fence Posts; Concrete Gate Posts; Corner Posts; Clothes Line
+ Posts; Grape Arbor Posts; Tanks; Troughs; Cisterns; Hog Wallows;
+ Feeding Floors and Barnyard Pavements; Foundations; Well Curbs
+ and Platforms; Indoor Floors; Sidewalks; Steps; Concrete Hotbeds
+ and Cold Frames; Concrete Slab Roofs; Walls for Buildings;
+ Repairing Leaks in Tanks and Cisterns; and all topics associated
+ with these subjects as bearing upon securing the best results
+ from concrete are dwelt upon at sufficient length in plain
+ every-day English so that the inexperienced person desiring to
+ undertake a piece of concrete construction can, by following the
+ directions set forth in this book, secure 100 per cent. success
+ every time. A number of convenient and practical tables for
+ estimating quantities, and some practical examples, are also
+ given. (5x7.) 149 pages. 51 illustrations. Price =75 cents=
+
+
+=Popular Handbook for Cement and Concrete Users.= By MYRON H. LEWIS.
+
+ This is a concise treatise of the principles and methods
+ employed in the manufacture and use of cement in all classes of
+ modern works. The author has brought together in this work all
+ the salient matter of interest to the user of concrete and its
+ many diversified products. The matter is presented in logical
+ and systematic order, clearly written, fully illustrated and
+ free from involved mathematics. Everything of value to the
+ concrete user is given, including kinds of cement employed in
+ construction, concrete architecture, inspection and testing,
+ waterproofing, coloring and painting, rules, tables, working and
+ cost data. The book comprises thirty-three chapters, as follow:
+ Introductory. Kinds of Cement and How They are Made. Properties.
+ Testing and Requirements of Hydraulic Cement. Concrete and Its
+ Properties. Sand, Broken Stone and Gravel for Concrete. How to
+ Proportion the Materials. How to Mix and Place Concrete. Forms
+ of Concrete Construction. The Architectural and Artistic
+ Possibilities of Concrete. Concrete Residences. Mortars,
+ Plasters and Stucco, and How to Use Them. The Artistic Treatment
+ of Concrete Surfaces. Concrete Building Blocks. The Making of
+ Ornamental Concrete. Concrete Pipes, Fences, Posts, etc.
+ Essential Features and Advantages of Reenforced Concrete. How to
+ Design Reenforced Concrete Beams, Slabs and Columns.
+ Explanations of the Methods and Principles in Designing
+ Reenforced Concrete, Beams and Slabs. Systems of Reenforcement
+ Employed. Reenforced Concrete in Factory and General Building
+ Construction. Concrete in Foundation Work. Concrete Retaining
+ Walls, Abutments and Bulkheads. Concrete Arches and Arch
+ Bridges. Concrete Beam and Girder Bridges. Concrete in Sewerage
+ and Draining Works. Concrete Tanks, Dams and Reservoirs.
+ Concrete Sidewalks, Curbs and Pavements. Concrete in Railroad
+ Construction. The Utility of Concrete on the Farm. The
+ Waterproofing of Concrete Structures. Grout of Liquid Concrete
+ and Its Use. Inspection of Concrete Work. Cost of Concrete Work.
+ Some of the special features of the book are: 1.--The Attention
+ Paid to the Artistic and Architectural Side of Concrete Work.
+ 2.--The Authoritative Treatment of the Problem of Waterproofing
+ Concrete. 3.--An Excellent Summary of the Rules to be Followed
+ in Concrete Construction. 4.--The Valuable Cost Data and Useful
+ Tables given. A valuable Addition to the Library of Every Cement
+ and Concrete User. Price =$2.50=
+
+ WHAT IS SAID OF THIS BOOK:
+
+ "The field of Concrete Construction is well covered and the
+ matter contained is well within the understanding of any
+ person."--_Engineering-Contracting._
+
+ "Should be on the bookshelves of every contractor, engineer, and
+ architect in the land."--_National Builder._
+
+
+=Waterproofing Concrete.= By MYRON H. LEWIS.
+
+ Modern Methods of Waterproofing Concrete and Other Structures. A
+ condensed statement of the Principles, Rules, and Precautions to
+ be Observed in Waterproofing and Dampproofing Structures and
+ Structural Materials. Paper binding. Illustrated. Price =50
+ cents=
+
+
+~DICTIONARIES~
+
+
+=Aviation Terms, Termes D'Aviation, English-French, French-English.=
+Compiled by Lieuts. VICTOR W. PAGE, A.S., S.C.U.S.R., and PAUL
+MONTARIOL, of the French Flying Corps, on duty on Signal Corps Aviation
+School, Mineola, L. I.
+
+ The lists contained are confined to essentials, and special
+ folding plates are included to show all important airplane
+ parts. The lists are divided in four sections as follows:
+ 1.--Flying Field Terms. 2.--The Airplane. 3.--The Engine.
+ 4.--Tools and Shop Terms.
+
+ A complete, well illustrated volume intended to facilitate
+ conversation between English-speaking and French aviators. A
+ very valuable book for all who are about to leave for duty
+ overseas.
+
+ Approved for publication by Major W. G. Kilner, S.C., U.S.C.O.
+ Signal Corps Aviation School, Hazelhurst Field, Mineola, L. I.
+ This book should be in every Aviator's and Mechanic's Kit for
+ ready reference. 128 pages, fully illustrated, with detailed
+ engravings. Price =$1.00=
+
+
+=Standard Electrical Dictionary.= By T. O'CONOR SLOANE.
+
+ An indispensable work to all interested in electrical science.
+ Suitable alike for the student and professional. A practical
+ handbook of reference containing definitions of about 5,000
+ distinct words, terms and phrases. The definitions are terse and
+ concise; and include every term used in electrical science.
+ Recently issued. An entirely new edition. Should be in the
+ possession of all who desire to keep abreast with the progress
+ of this branch of science. Complete, concise and convenient. 682
+ pages, 393 illustrations. Price =$3.00=
+
+
+~DIES--METAL WORK~
+
+
+=Dies: Their Construction and Use for the Modern Working of Sheet
+Metals.= By J. V. WOODWORTH.
+
+ A most useful book, and one which should be in the hands of all
+ engaged in the press working of metals; treating on the
+ Designing, Constructing, and Use of Tools, Fixtures and Devices,
+ together with the manner in which they should be used in the
+ Power Press, for the cheap and rapid production of the great
+ variety of sheet-metal articles now in use. It is designed as a
+ guide to the production of sheet-metal parts at the minimum of
+ cost with the maximum of output. The hardening and tempering of
+ Press tools and the classes of work which may be produced to the
+ best advantage by the use of dies in the power press are fully
+ treated. Its 515 illustrations show dies, press fixtures and
+ sheet-metal working devices, the descriptions of which are so
+ clear and practical that all metal-working mechanics will be
+ able to understand how to design, construct and use them. Many
+ of the dies and press fixtures treated were either constructed
+ by the author or under his supervision. Others were built by
+ skilful mechanics and are in use in large sheet-metal
+ establishments and machine shops. 6th Revised and Enlarged
+ Edition. Price =$3.00=
+
+
+=Punches, Dies and Tools for Manufacturing in Presses.= By J. V.
+WOODWORTH.
+
+ This work is a companion volume to the author's elementary work
+ entitled "Dies: Their Construction and Use." It does not go into
+ the details of die-making to the extent of the author's previous
+ book, but gives a comprehensive review of the field of
+ operations carried on by presses. A large part of the
+ information given has been drawn from the author's personal
+ experience. It might well be termed an Encyclopedia of
+ Die-Making, Punch-Making, Die-Sinking, Sheet-Metal Working, and
+ Making of Special Tools, Sub-presses, Devices and Mechanical
+ Combinations for Punching, Cutting, Bending, Forming, Piercing,
+ Drawing, Compressing and Assembling Sheet-Metal Parts, and also
+ Articles of other Materials in Machine Tools. 2d Edition. Price
+ =$4.00=
+
+
+=Drop Forging, Die-Sinking and Machine-Forming of Steel.= By J. V.
+WOODWORTH.
+
+ This is a practical treatise on Modern Shop Practice, Processes,
+ Methods, Machine Tools, and Details treating on the Hot and Cold
+ Machine-Forming of Steel and Iron into Finished Shapes: together
+ with Tools, Dies, and Machinery involved in the manufacture of
+ Duplicate Forgings and Interchangeable Hot and Cold Pressed
+ Parts from Bar and Sheet Metal. This book fills a demand of long
+ standing for information regarding drop-forgings, die-sinking
+ and machine-forming of steel and the shop practice involved, as
+ it actually exists in the modern drop-forging shop. The
+ processes of die-sinking and force-making, which are thoroughly
+ described and illustrated in this admirable work, are rarely to
+ be found explained in such a clear and concise manner as is here
+ set forth. The process of die-sinking relates to the engraving
+ or sinking of the female or lower dies, such as are used for
+ drop-forgings, hot and cold machine-forging, swedging, and the
+ press working of metals. The process of force-making relates to
+ the engraving or raising of the male or upper dies used in
+ producing the lower dies for the press-forming and
+ machine-forging of duplicate parts of metal.
+
+ In addition to the arts above mentioned the book contains
+ explicit information regarding the drop-forging and hardening
+ plants, designs, conditions, equipment, drop hammers, forging
+ machines, etc., machine forging, hydraulic forging, autogenous
+ welding and shop practice. The book contains eleven chapters,
+ and the information contained in these chapters is just what
+ will prove most valuable to the forged-metal worker. All
+ operations described in the work are thoroughly illustrated by
+ means of perspective half-tones and outline sketches of the
+ machinery employed. 300 detailed illustrations. Price =$2.50=
+
+
+~DRAWING--SKETCHING PAPER~
+
+
+=Practical Perspective.= By RICHARDS and COLVIN.
+
+ Shows just how to make all kinds of mechanical drawings in the
+ only practical perspective isometric. Makes everything plain, so
+ that any mechanic can understand a sketch or drawing in this
+ way. Saves time in the drawing room, and mistakes in the shops.
+ Contains practical examples of various classes of work. 4th
+ Edition. Price =50 cents=
+
+
+=Linear Perspective Self-Taught.= By HERMAN T. C. KRAUS.
+
+ This work gives the theory and practice of linear perspective,
+ as used in architectural, engineering and mechanical drawings.
+ Persons taking up the study of the subject by themselves will be
+ able, by the use of the instruction given, to readily grasp the
+ subject, and by reasonable practice become good perspective
+ draftsmen. The arrangement of the book is good; the plate is on
+ the left-hand, while the descriptive text follows on the
+ opposite page, so as to be readily referred to. The drawings are
+ on sufficiently large scale to show the work clearly and are
+ plainly figured. There is included a self-explanatory chart
+ which gives all information necessary for the thorough
+ understanding of perspective. This chart alone is worth many
+ times over the price of the book. 2d Revised and Enlarged
+ Edition. Price =$2.50=
+
+
+=Self-Taught Mechanical Drawing and Elementary Machine Design.= By F. L.
+SYLVESTER, M.E., Draftsman, with additions by ERIK OBERG, associate
+editor of "Machinery."
+
+ This is a practical treatise on Mechanical Drawing and Machine
+ Design, comprising the first principles of geometric and
+ mechanical drawing, workshop mathematics, mechanics, strength of
+ materials and the calculations and design of machine details.
+ The author's aim has been to adapt this treatise to the
+ requirements of the practical mechanic and young draftsman and
+ to present the matter in as clear and concise a manner as
+ possible. To meet the demands of this class of students,
+ practically all the important elements of machine design have
+ been dealt with, and in addition algebraic formulas have been
+ explained, and the elements of trigonometry treated in the
+ manner best suited to the needs of the practical man. The book
+ is divided into 20 chapters, and in arranging the material,
+ mechanical drawing, pure and simple, has been taken up first, as
+ a thorough understanding of the principles of representing
+ objects facilitates the further study of mechanical subjects.
+ This is followed by the mathematics necessary for the solution
+ of the problems in machine design which are presented later, and
+ a practical introduction to theoretical mechanics and the
+ strength of materials. The various elements entering into
+ machine design, such as cams, gears, sprocket-wheels, cone
+ pulleys, bolts, screws, couplings, clutches, shafting and
+ fly-wheels, have been treated in such a way as to make possible
+ the use of the work as a text-book for a continuous course of
+ study. It is easily comprehended and assimilated even by
+ students of limited previous training. 330 pages, 215
+ engravings. Price =$2.00=
+
+
+=A New Sketching Paper.=
+
+ A new specially ruled paper to enable you to make sketches or
+ drawings in isometric perspective without any figuring or
+ fussing. It is being used for shop details as well as for
+ assembly drawings, as it makes one sketch do the work of three,
+ and no workman can help seeing just what is wanted.
+
+ Pads of 40 sheets, 6x9 inches. Price =25 cents=
+ Pads of 40 sheets, 9x12 inches. Price =50 cents=
+ 40 sheets, 12x18 inches. Price =$1.00=
+
+
+~ELECTRICITY~
+
+
+=Arithmetic of Electricity.= By Prof. T. O'CONOR SLOANE.
+
+ A practical treatise on electrical calculations of all kinds
+ reduced to a series of rules, all of the simplest forms, and
+ involving only ordinary arithmetic; each rule illustrated by one
+ or more practical problems, with detailed solution of each one.
+ This book is classed among the most useful works published on
+ the science of electricity, covering as it does the mathematics
+ of electricity in a manner that will attract the attention of
+ those who are not familiar with algebraical formulas. 20th
+ Edition. 160 pages. Price =$1.00=
+
+
+=Commutator Construction.= By WM. BAXTER, JR.
+
+ The business end of any dynamo or motor of the direct current
+ type is the commutator. This book goes into the designing,
+ building, and maintenance of commutators, shows how to locate
+ troubles and how to remedy them; everyone who fusses with
+ dynamos needs this. 4th Edition. Price =25 cents=
+
+
+=Dynamo Building for Amateurs, or How to Construct a Fifty-Watt Dynamo.=
+By ARTHUR J. WEED, Member of N. Y. Electrical Society.
+
+ A practical treatise showing in detail the construction of a
+ small dynamo or motor, the entire machine work of which can be
+ done on a small foot lathe. Dimensioned working drawings are
+ given for each piece of machine work, and each operation is
+ clearly described. This machine, when used as a dynamo, has an
+ output of fifty watts; when used as a motor it will drive a
+ small drill press or lathe. It can be used to drive a sewing
+ machine on any and all ordinary work. The book is illustrated
+ with more than sixty original engravings, showing the actual
+ construction of the different parts. Among the contents are
+ chapters on: 1. Fifty-Watt Dynamo. 2. Side Bearing Rods. 3.
+ Field Punching. 4. Bearings. 5. Commutator. 6. Pulley. 7. Brush
+ Holders. 8. Connection Board. 9. Armature Shaft. 10. Armature.
+ 11. Armature Winding. 12. Field Winding. 13. Connecting and
+ starting.
+
+ Paper. Price =50 Cents=
+ Cloth. Price =$1.00=
+
+
+=Electric Bells.= By M. B. SLEEPER.
+
+ A complete treatise for the practical worker in Installing,
+ Operating and Testing Bell Circuits, Burglar Alarms,
+ Thermostats, and other apparatus used with Electric Bells.
+
+ Both the electrician and the experimenter will find in this book
+ new material which is essential in their work. Tools, bells,
+ batteries, unusual circuits, burglar alarms, annunciator
+ systems, thermostats, circuit breakers, time alarms, and other
+ apparatus used in bell circuits are described from the
+ standpoints of their application, construction and repair. The
+ detailed instruction for building the apparatus will appeal to
+ the experimenter particularly.
+
+ The practical worker will find the chapter on Wiring,
+ Calculation of Wire Sizes and Magnet Winding, Upkeep of Systems,
+ and the Location of Faults, of the greatest value in their work.
+ Among the chapters are: Tools and Materials for Bell Work; How
+ and Why Bell Work; Batteries for Small Installations; Making
+ Bells and Push Buttons; Wiring Bell Systems; Construction of
+ Annunciators and Signals; Burglary Alarms and Auxiliary
+ Apparatus; More Elaborate Bell Systems; Finding Faults and
+ Remedying Them. 124 pages, fully illustrated. Price =50 cents=
+
+
+=Electric Lighting and Heating Pocket Book.= By SYDNEY F. WALKER.
+
+ This book puts in convenient form useful information regarding
+ the apparatus which is likely to be attached to the mains of an
+ electrical company. Tables of units and equivalents are included
+ and useful electrical laws and formulas are stated. 438 pages,
+ 300 engravings. Bound in leather. Pocket book form. Price
+ =$3.00=
+
+
+=Electric Wiring, Diagrams and Switchboards.= By NEWTON HARRISON, with
+additions by THOMAS POPPE.
+
+ A thoroughly practical treatise covering the subject of Electric
+ Wiring in all its branches, deluding explanations and diagrams
+ which are thoroughly explicit and greatly simplify the subject.
+ Practical every-day problems in wiring are presented and the
+ method of obtaining intelligent results clearly shown. Only
+ arithmetic is used. Ohm's law is given a simple explanation with
+ reference to wiring for direct and alternating currents. The
+ fundamental principle of drop of potential in circuits is shown
+ with its various applications. The simple circuit is developed
+ with the position of mains, feeders and branches; their
+ treatment as a part of a wiring plan and their employment in
+ house wiring clearly illustrated. Some simple facts about
+ testing are included in connection with the wiring. Molding and
+ conduit work are given careful consideration; and switchboards
+ are systematically treated, built up and illustrated, showing
+ the purpose they serve, for connection with the circuits, and to
+ shunt and compound wound machines. The simple principles of
+ switchboard construction, the development of the switchboard,
+ the connections of the various instruments, including the
+ lightning arrester, are also plainly set forth.
+
+ Alternating current wiring is treated, with explanations of the
+ power factor, conditions calling for various sizes of wire, and
+ a simple way of obtaining the sizes for single-phase, two-phase
+ and three-phase circuits. This is the only complete work issued
+ showing and telling you what you should know about direct and
+ alternating current wiring. It is a ready reference. The work is
+ free from advanced technicalities and mathematics, arithmetic
+ being used throughout. It is in every respect a handy,
+ well-written, instructive, comprehensive volume on wiring for
+ the wireman, foreman, contractor, or electrician. 2nd Revised
+ Edition. 303 pages, 130 illustrations. Price =$1.50=
+
+
+=Electric Furnaces and their Industrial Applications.= By J. WRIGHT.
+
+ This is a book which will prove of interest to many classes of
+ people: the manufacturer who desires to know what product can be
+ manufactured successfully in the electric furnace, the chemist
+ who wishes to post himself on the electro-chemistry, and the
+ student of science who merely looks into the subject from
+ curiosity. New, Revised and Enlarged Edition. 320 pages. Fully
+ illustrated, cloth. Price =$3.00=
+
+
+=Electric Toy Making, Dynamo Building, and Electric Motor Construction.=
+By Prof. T. O'CONOR SLOANE.
+
+ This work treats of the making at home of electrical toys,
+ electrical apparatus, motors, dynamos, and instruments in
+ general, and is designed to bring within the reach of young and
+ old the manufacture of genuine and useful electrical appliances.
+ The work is especially designed for amateurs and young folks.
+
+ Thousands of our young people are daily experimenting, and
+ busily engaged in making electrical toys and apparatus of
+ various kinds. The present work is just what is wanted to give
+ the much needed information in a plain, practical manner, with
+ illustrations to make easy the carrying out of the work. 20th
+ Edition. Price =$1.00=
+
+
+=Practical Electricity.= By Prof. T. O'CONOR SLOANE.
+
+ This work of 768 pages was previously known as Sloane's
+ Electricians' Hand Book, and is intended for the practical
+ electrician who has to make things go. The entire field of
+ electricity is covered within its pages. Among some of the
+ subjects treated are: The Theory of the Electric Current and
+ Circuit, Electro-Chemistry, Primary Batteries, Storage
+ Batteries, Generation and Utilization of Electric Powers,
+ Alternating Current, Armature Winding, Dynamos and Motors, Motor
+ Generators, Operation of the Central Station Switchboards,
+ Safety Appliances, Distribution of Electric Light and Power,
+ Street Mains, Transformers, Arc and Incandescent Lighting,
+ Electric Measurements, Photometry, Electric Railways, Telephony,
+ Bell-Wiring, Electric-Plating, Electric Heating, Wireless
+ Telegraphy, etc. It contains no useless theory; everything is to
+ the point. It teaches you just what you want to know about
+ electricity. It is the standard work published on the subject.
+ Forty-one chapters, 556 engravings. Price =$2.50=
+
+
+=Electricity Simplified.= By Prof. T. O'CONOR SLOANE.
+
+ The object of "Electricity Simplified" is to make the subject as
+ plain as possible and to show what the modern conception of
+ electricity is; to show how two plates of different metal,
+ immersed in acid, can send a message around the globe; to
+ explain how a bundle of copper wire rotated by a steam engine
+ can be the agent in lighting our streets; to tell what the volt,
+ ohm and ampere are, and what high and low tension mean; and to
+ answer the questions that perpetually arise in the mind in this
+ age of electricity. 13th Edition. 172 pages. Illustrated. Price
+ =$1.00=
+
+
+=House Wiring.= By THOMAS W. POPPE.
+
+ This work describes and illustrates the actual installation of
+ Electric Light Wiring, the manner in which the work should be
+ done, and the method of doing it. The book can be conveniently
+ carried in the pocket. It is intended for the Electrician,
+ Helper and Apprentice. It solves all Wiring Problems and
+ contains nothing that conflicts with the rulings of the National
+ Board of Fire Underwriters. It gives just the information
+ essential to the Successful Wiring of a Building. Among the
+ subjects treated are: Locating the Meter. Panel-Boards.
+ Switches. Plug Receptacles. Brackets. Ceiling Fixtures. The
+ Meter Connections. The Feed Wires. The Steel Armored Cable
+ System. The Flexible Steel Conduit System. The Ridig Conduit
+ System. A digest of the National Board of Fire Underwriters'
+ rules relating to metallic wiring systems. Various switching
+ arrangements explained and diagrammed. The easiest method of
+ testing the Three- and Four-way circuits explained. The
+ grounding of all metallic wiring systems and the reason for
+ doing so shown and explained. The insulation of the metal parts
+ of lamp fixtures and the reason for the same described and
+ illustrated. 125 pages. 2nd Edition, revised and enlarged. Fully
+ illustrated. Flexible cloth. Price =50 cents=
+
+
+=How to Become a Successful Electrician.= By Prof. T. O'CONOR SLOANE.
+
+ Every young man who wishes to become a successful electrician
+ should read this book. It tells in simple language the surest
+ and easiest way to become a successful electrician. The studies
+ to be followed, methods of work, field of operation and the
+ requirements of the successful electrician are pointed out and
+ fully explained. Every young engineer will find this an
+ excellent stepping stone to more advanced works on electricity
+ which he must master before success can be attained. Many young
+ men become discouraged at the very outstart by attempting to
+ read and study books that are far beyond their comprehension.
+ This book serves as the connecting link between the rudiments
+ taught in the public schools and the real study of electricity.
+ It is interesting from cover to cover. 18th Revised Edition,
+ just issued. 205 pages. Illustrated. Price =$1.00=
+
+
+=Management of Dynamos.= By LUMMIS-PATERSON.
+
+ A handbook of theory and practice. This work is arranged in
+ three parts. The first part covers the elementary theory of the
+ dynamo. The second part, the construction and action of the
+ different classes of dynamos in common use are described; while
+ the third part relates to such matters as affect the practical
+ management and working of dynamos and motors. 4th Edition. 292
+ pages, 117 illustrations. Price =$1.50=
+
+
+=Standard Electrical Dictionary.= By T. O'CONOR SLOANE.
+
+ An indispensable work to all interested in electrical science.
+ Suitable alike for the student and professional. A practical
+ handbook of reference containing definitions of about 5,000
+ distinct words, terms and phrases. The definitions are terse and
+ concise and include every term used in electrical science.
+ Recently issued. An entirely new edition. Should be in the
+ possession of all who desire to keep abreast with the progress
+ of this branch of science. In its arrangement and typography the
+ book is very convenient. The word or term defined is printed in
+ black-faced type, which readily catches the eye, while the body
+ of the page is in smaller but distinct type. The definitions are
+ well worded, and so as to be understood by the non-technical
+ reader. The general plan seems to be to give an exact, concise
+ definition, and then amplify and explain in a more popular way.
+ Synonyms are also given, and references to other words and
+ phrases are made. A very complete and accurate index of fifty
+ pages is at the end of the volume; and as this index contains
+ all synonyms, and as all phrases are indexed in every reasonable
+ combination of words, reference to the proper place in the body
+ of the book is readily made. It is difficult to decide how far a
+ book of this character is to keep the dictionary form, and to
+ what extent it may assume the encyclopedia form. For some
+ purposes, concise, exactly worded definitions are needed; for
+ other purposes, more extended descriptions are required. This
+ book seeks to satisfy both demands, and does it with
+ considerable success. 682 pages, 393 illustrations. 12th
+ Edition. Price =$3.00=
+
+
+=Storage Batteries Simplified.= By VICTOR W. PAGE, M.E.
+
+ A complete treatise on storage battery operating principles,
+ repairs and applications. The greatly increasing application of
+ storage batteries in modern engineering and mechanical work has
+ created a demand for a book that will consider this subject
+ completely and exclusively. This is the most thorough and
+ authoritative treatise ever published on this subject. It is
+ written in easily understandable, non-technical language so that
+ any one may grasp the basic principles of storage battery action
+ as well as their practical industrial applications. All electric
+ and gasoline automobiles use storage batteries. Every automobile
+ repairman, dealer or salesman should have a good knowledge of
+ maintenance and repair of these important elements of the motor
+ car mechanism. This book not only tells how to charge, care for
+ and rebuild storage batteries but also outlines all the
+ industrial uses. Learn how they run street cars, locomotives and
+ factory trucks. Get an understanding of the important functions
+ they perform in submarine boats, isolated lighting plants,
+ railway switch and signal systems, marine applications, etc.
+ This book tells how they are used in central station standby
+ service, for starting automobile motors and in ignition systems.
+ Every practical use of the modern storage battery is outlined in
+ this treatise. 320 pages, fully illustrated. Price =$1.50=
+
+
+=Switchboards.= By WILLIAM BAXTER, JR.
+
+ This book appeals to every engineer and electrician who wants to
+ know the practical side of things. It takes up all sorts and
+ conditions of dynamos, connections and circuits, and shows by
+ diagram and illustration just how the switchboard should be
+ connected. Includes direct and alternating current boards, also
+ those for arc lighting, incandescent and power circuits. Special
+ treatment on high voltage boards for power transmission. 2nd
+ Edition. 190 pages, Illustrated. Price =$1.50=
+
+
+=Telephone Construction, Installation, Wiring, Operation and
+Maintenance.= By W. H. RADCLIFFE and H. C. CUSHING.
+
+ This book is intended for the amateur, the wireman, or the
+ engineer who desires to establish a means of telephonic
+ communication between the rooms of his home, office, or shop. It
+ deals only with such things as may be of use to him rather than
+ with theories.
+
+ Gives the principles of construction and operation of both the
+ Bell and Independent instruments; approved methods of installing
+ and wiring them; the means of protecting them from lightning and
+ abnormal currents; their connection together for operation as
+ series or bridging stations; and rules for their inspection and
+ maintenance. Line wiring and the wiring and operation of special
+ telephone systems are also treated. Intricate mathematics are
+ avoided, and all apparatus, circuits and systems are thoroughly
+ described. The appendix contains definitions of units and terms
+ used in the text. Selected wiring tables, which are very
+ helpful, are also included. Among the subjects treated are
+ Construction, Operation, and Installation of Telephone
+ Instruments; Inspection and Maintenance of Telephone
+ Instruments; Telephone Line Wiring; Testing Telephone Line Wires
+ and Cables; Wiring and Operation of Special Telephone Systems,
+ etc. 2nd Edition, Revised and Enlarged. 223 pages, 154
+ illustrations. Price =$1.00=
+
+
+=Wireless Telegraphy and Telephony Simply Explained.= By ALFRED P.
+MORGAN.
+
+ This is undoubtedly one of the most complete and comprehensible
+ treatises on the subject ever published, and a close study of
+ its pages will enable one to master all the details of the
+ wireless transmission of messages. The author has filled a
+ long-felt want and has succeeded in furnishing a lucid,
+ comprehensible explanation in simple language of the theory and
+ practice of wireless telegraphy and telephony.
+
+ Among the contents are: Introductory; Wireless Transmission and
+ Reception--The Aerial System, Earth Connections--The
+ Transmitting Apparatus, Spark Coils and Transformers,
+ Condensers, Helixes, Spark Gaps, Anchor Gaps, Aerial
+ Switches--The Receiving Apparatus, Detectors, etc.--Tuning and
+ Coupling, Tuning Coils, Loose Couplers, Variable Condensers,
+ Directive Wave Systems--Miscellaneous Apparatus, Telephone
+ Receivers, Range of Stations, Static Interference--Wireless
+ Telephones, Sound and Sound Waves, The Vocal Cords and
+ Ear--Wireless Telephone, How Sounds Are Changed into Electric
+ Waves--Wireless Telephones, The Apparatus--Summary. 154 pages,
+ 156 engravings. Price =$1.00=
+
+
+=Wiring a House.= By HERBERT PRATT.
+
+ Shows a house already built; tells just how to start about
+ wiring it; where to begin; what wire to use; how to run it
+ according to Insurance Rules; in fact, just the information you
+ need. Directions apply equally to a shop. 4th Edition. Price =25
+ cents=
+
+
+~FACTORY MANAGEMENT, ETC.~
+
+
+=Modern Machine Shop Construction, Equipment and Management.= By O. E.
+PERRIGO, M.E.
+
+ The only work published that describes the modern machine shop
+ or manufacturing plant from the time the grass is growing on the
+ site intended for it until the finished product is shipped. By a
+ careful study of its thirty-two chapters the practical man may
+ economically build, efficiently equip, and successfully manage
+ the modern machine shop or manufacturing establishment. Just the
+ book needed by those contemplating the erection of modern shop
+ buildings, the rebuilding and reorganization of old ones, or the
+ introduction of modern shop methods, time and cost systems. It
+ is a book written and illustrated by a practical shop man for
+ practical shop men who are too busy to read _theories_ and want
+ _facts_. It is the most complete all-around book of its kind
+ ever published. It is a practical book for practical men, from
+ the apprentice in the shop to the president in the office. It
+ minutely describes and illustrates the most simple and yet the
+ most efficient time and cost system yet devised. 2nd Revised and
+ Enlarged Edition, just issued. 384 pages, 219 illustrations.
+ Price =$5.00=
+
+
+~FUEL~
+
+
+=Combustion of Coal and the Prevention of Smoke.= By WM. M. BARR.
+
+ This book has been prepared with special reference to the
+ generation of heat by the combustion of the common fuels found
+ in the United States, and deals particularly with the conditions
+ necessary to the economic and smokeless combustion of bituminous
+ coals in Stationary and Locomotive Steam Boilers.
+
+ The presentation of this important subject is systematic and
+ progressive. The arrangement of the book is in a series of
+ practical questions to which are appended accurate answers,
+ which describe in language, free from technicalities, the
+ several processes involved in the furnace combustion of American
+ fuels; it clearly states the essential requisites for perfect
+ combustion, and points out the best methods for furnace
+ construction for obtaining the greatest quantity of heat from
+ any given quality of coal. Nearly 350 pages, fully illustrated.
+ Price =$1.00=
+
+
+=Smoke Prevention and Fuel Economy.= By BOOTH and KERSHAW.
+
+ A complete treatise for all interested in smoke prevention and
+ combustion, being based on the German work of Ernst Schmatolla,
+ but it is more than a mere translation of the German treatise,
+ much being added. The authors show as briefly as possible the
+ principles of fuel combustion, the methods which have been and
+ are at present in use, as well as the proper scientific methods
+ for obtaining all the energy in the coal and burning it without
+ smoke. Considerable space is also given to the examination of
+ the waste gases, and several of the representative English and
+ American mechanical stoker and similar appliances are described.
+ The losses carried away in the waste gases are thoroughly
+ analyzed and discussed in the Appendix, and abstracts are also
+ here given of various patents on combustion apparatus. The book
+ is complete and contains much of value to all who have charge of
+ large plants. 194 pages. Illustrated. Price =$2.50=
+
+
+~GAS ENGINES AND GAS~
+
+
+=Gas, Gasoline and Oil Engines.= By GARDNER D. HISCOX. Revised by VICTOR
+W. PAGE, M.E.
+
+ Just issued New 1918 Edition, Revised and Enlarged. Every user
+ of a gas engine needs this book. Simple, instructive and right
+ up-to-date. The only complete work on the subject. Tells all
+ about internal combustion engineering, treating exhaustively on
+ the design, construction and practical application of all forms
+ of gas, gasoline, kerosene and crude petroleum-oil engines.
+ Describes minutely all auxiliary systems, such as lubrication,
+ carburetion and ignition. Considers the theory and management of
+ all forms of explosive motors for stationary and marine work,
+ automobiles, aeroplanes and motor-cycles. Includes also Producer
+ Gas and Its Production. Invaluable instructions for all
+ students, gas-engine owners, gas-engineers, patent experts,
+ designers, mechanics, draftsmen and all having to do with the
+ modern power. Illustrated by over 400 engravings, many specially
+ made from engineering drawings, all in correct proportion. 650
+ pages, 435 engravings. Price =$2.50 net=
+
+
+=The Gasoline Engine on the Farm: Its Operation, Repair and Uses.= By
+XENO W. PUTNAM.
+
+ This is a practical treatise on the Gasoline and Kerosene Engine
+ intended for the man who wants to know just how to manage his
+ engine and how to apply it to all kinds of farm work to the best
+ advantage.
+
+ This book abounds with hints and helps for the farm and
+ suggestions for the home and house-wife. There is so much of
+ value in this book that it is impossible to adequately describe
+ it in such small space. Suffice to say that it is the kind of a
+ book every farmer will appreciate and every farm home ought to
+ have. Includes selecting the most suitable engine for farm work,
+ its most convenient and efficient installation, with chapters on
+ troubles, their remedies, and how to avoid them. The care and
+ management of the farm tractor in plowing, harrowing, harvesting
+ and road grading are fully covered; also plain directions are
+ given for handling the tractor on the road. Special attention is
+ given to relieving farm life of its drudgery by applying power
+ to the disagreeable small tasks which must otherwise be done by
+ hand. Many home made contrivances for cutting wood, supplying
+ kitchen, garden, and barn with water, loading, hauling and
+ unloading hay, delivering grain to the bins or the feed trough
+ are included; also full directions for making the engine milk
+ the cows, churn, wash, sweep the house and clean the windows,
+ etc. Very fully illustrated with drawings of working parts and
+ cuts showing Stationary, Portable and Tractor Engines doing all
+ kinds of farm work. All money-making farms utilize power. Learn
+ how to utilize power by reading the pages of this book. It is an
+ aid to the result getter, invaluable to the up-to-date farmer,
+ student, blacksmith, implement dealer and, in fact, all who can
+ apply practical knowledge of stationary gasoline engines or gas
+ tractors to advantage. 530 pages. Nearly 180 engravings. Price
+ =$2.00=
+
+ WHAT IS SAID OF THIS BOOK:
+
+ "Am much pleased with the book and find it to be very complete
+ and up-to-date. I will heartily recommend it to students and
+ farmers whom I think would stand in need of such a work, as I
+ think it is an exceptionally good one."--_N. S. Gardiner_, Prof.
+ in Charge, Clemson Agr. College of S. C.; Dept. of Agri. and
+ Agri. Exp. Station, Clemson College, S. C.
+
+ "I feel that Mr. Putnam's book covers the main points which a
+ farmer should know."--_R. T. Burdick_, Instructor in Agronomy,
+ University of Vermont, Burlington, Vt.
+
+
+=Gasoline Engines: Their Operation, Use and Care.= By A. HYATT VERRILL.
+
+ The simplest, latest and most comprehensive popular work
+ published on Gasoline Engines, describing what the Gasoline
+ Engine is; its construction and operation; how to install it;
+ how to select it; how to use it and how to remedy troubles
+ encountered. Intended for Owners, Operators and Users of
+ Gasoline Motors of all kinds. This work fully describes and
+ illustrates the various types of Gasoline Engines used in Motor
+ Boats, Motor Vehicles and Stationary Work. The parts,
+ accessories and appliances are described with chapters on
+ ignition, fuel, lubrication, operation and engine troubles.
+ Special attention is given to the care, operation and repair of
+ motors, with useful hints and suggestions on emergency repairs
+ and makeshifts. A complete glossary of technical terms and an
+ alphabetically arranged table of troubles and their symptoms
+ form most valuable and unique features of this manual. Nearly
+ every illustration in the book is original, having been made by
+ the author. Every page is full of interest and value. A book
+ which you cannot afford to be without. 275 pages, 152 specially
+ made engravings. Price =$1.50=
+
+
+=Gas Engine Construction, or How to Build a Half-horsepower Gas Engine.=
+By PARSELL and WEED.
+
+ A practical treatise of 300 pages describing the theory and
+ principles of the action of Gas Engines of various types and the
+ design and construction of a half-horsepower Gas Engine, with
+ illustrations of the work in actual progress, together with the
+ dimensioned working drawings, giving clearly the sizes of the
+ various details; for the student, the scientific investigator,
+ and the amateur mechanic. This book treats of the subject more
+ from the standpoint of practice than that of theory. The
+ principles of operation of Gas Engines are clearly and simply
+ described, and then the actual construction of a half-horsepower
+ engine is taken up, step by step, showing in detail the making
+ of the Gas Engine. 3rd Edition. 300 pages. Price =$2.50=
+
+
+=How to Run and Install Two- and Four-Cycle Marine Gasoline Engines.= By
+C. VON CULIN.
+
+ Revised and enlarged edition just issued. The object of this
+ little book is to furnish a pocket instructor for the beginner,
+ the busy man who uses an engine for pleasure or profit, but who
+ does not have the time or inclination for a technical book, but
+ simply to thoroughly understand how to properly operate, install
+ and care for his own engine. The index refers to each trouble,
+ remedy, and subject alphabetically. Being a quick reference to
+ find the cause, remedy and prevention for troubles, and to
+ become an expert with his own engine. Pocket size. Paper
+ binding. Price =25 cents=
+
+
+=Modern Gas Engines and Producer Gas Plants.= By R. E. MATHOT.
+
+ A guide for the gas engine designer, user, and engineer in the
+ construction, selection, purchase, installation, operation, and
+ maintenance of gas engines. More than one book on gas engines
+ has been written, but not one has thus far even encroached on
+ the field covered by this book. Above all, Mr. Mathot's work is
+ a practical guide. Recognizing the need of a volume that would
+ assist the gas engine user in understanding thoroughly the motor
+ upon which he depends for power, the author has discussed his
+ subject without the help of any mathematics and without
+ elaborate theoretical explanations. Every part of the gas engine
+ is described in detail, tersely, clearly, with a thorough
+ understanding of the requirements of the mechanic. Helpful
+ suggestions as to the purchase of an engine, its installation,
+ care, and operation, form a most valuable feature of the work.
+ 320 pages, 175 detailed illustrations. Price =$2.50=
+
+
+=The Modern Gas Tractor.= By VICTOR W. PAGE, M. E.
+
+ A complete treatise describing all types and sizes of gasoline,
+ kerosene and oil tractors. Considers design and construction
+ exhaustively, gives complete instructions for care, operation
+ and repair, outlines all practical applications on the road and
+ in the field. The best and latest work on farm tractors and
+ tractor power plants. A work needed by farmers, students,
+ blacksmiths, mechanics, salesmen, implement dealers, designers
+ and engineers. 2nd Edition, Revised. 504 pages, 228
+ illustrations, 3 folding plates. Price =$2.00=
+
+
+~GEARING AND CAMS~
+
+
+=Bevel Gear Tables.= By D. AG. ENGSTROM.
+
+ A book that will at once commend itself to mechanics and
+ draftsmen. Does away with all the trigonometry and fancy
+ figuring on bevel gears, and makes it easy for anyone to lay
+ them out or make them just right. There are 36 full-page tables
+ that show every necessary dimension for all sizes or
+ combinations you're apt to need. No puzzling, figuring or
+ guessing. Gives placing distance, all the angles (including
+ cutting angles), and the correct cutter to use. A copy of this
+ prepares you for anything in the bevel-gear line. 3rd Edition.
+ 66 pages. Price =$1.00=
+
+
+=Change Gear Devices.= By OSCAR E. PERRIGO.
+
+ A practical book for every designer, draftsman, and mechanic
+ interested in the invention and development of the devices for
+ feed changes on the different machines requiring such mechanism.
+ All the necessary information on this subject is taken up,
+ analyzed, classified, sifted, and concentrated for the use of
+ busy men who have not the time to go through the masses of
+ irrelevant matter with which such a subject is usually
+ encumbered and select such information as will be useful to
+ them.
+
+ It shows just what has been done, how it has been done, when it
+ was done, and who did it. It saves time in hunting up patent
+ records and re-inventing old ideas. 88 pages. 3rd Edition. Price
+ =$1.00=
+
+
+=Drafting of Cams.= By LOUIS ROUILLION.
+
+ The laying out of cams is a serious problem unless you know how
+ to go at it right. This puts you on the right road for
+ practically any kind of cam you are likely to run up against.
+ 3rd Edition. Price =25 Cents=
+
+
+~HYDRAULICS~
+
+
+=Hydraulic Engineering.= By GARDNER D. HISCOX.
+
+ A treatise on the properties, power, and resources of water for
+ all purposes. Including the measurement of streams, the flow of
+ water in pipes or conduits; the horsepower of falling water,
+ turbine and impact water-wheels, wave motors, centrifugal,
+ reciprocating and air-lift pumps. With 300 figures and diagrams
+ and 36 practical tables. All who are interested in water-works
+ development will find this book a useful one, because it is an
+ entirely practical treatise upon a subject of present importance
+ and cannot fail in having a far-reaching influence, and for this
+ reason should have a place in the working library of every
+ engineer. Among the subjects treated are: Historical Hydraulics;
+ Properties of Water; Measurement of the Flow of Streams; Flow
+ from Sub-surface Orifices and Nozzles; Flow of Water in Pipes;
+ Siphons of Various Kinds; Dams and Great Storage Reservoirs;
+ City and Town Water Supply; Wells and Their Reinforcement;
+ Air-lift Methods of Raising Water; Artesian Wells; Irrigation of
+ Arid Districts; Water Power; Water Wheels; Pumps and Pumping
+ Machinery; Reciprocating Pumps; Hydraulic Power Transmission;
+ Hydraulic Mining; Canals; Ditches; Conduits and Pipe Lines;
+ Marine Hydraulics; Tidal and Sea Wave Power, etc. 320 pages.
+ Price =$4.00=
+
+
+~ICE AND REFRIGERATION~
+
+
+=Pocketbook of Refrigeration and Ice Making.= By A. J. WALLIS-TAYLOR.
+
+ This is one of the latest and most comprehensive reference books
+ published on the subject of refrigeration and cold storage. It
+ explains the properties and refrigerating effect of the
+ different fluids in use, the management of refrigerating
+ machinery and the construction and insulation of cold rooms with
+ their required pipe surface for different degrees of cold;
+ freezing mixtures and non-freezing brines, temperatures of cold
+ rooms for all kinds of provisions, cold storage charges for all
+ classes of goods, ice making and storage of ice, data and
+ memoranda for constant reference by refrigerating engineers,
+ with nearly one hundred tables containing valuable references to
+ every fact and condition required in the installment and
+ operation of a refrigerating plant. New edition just published.
+ Price =$1.50=
+
+
+~INVENTIONS--PATENTS~
+
+
+=Inventors' Manual: How to Make a Patent Pay.=
+
+ This is a book designed as a guide to inventors in perfecting
+ their inventions, taking out their patents and disposing of
+ them. It is not in any sense a Patent Solicitor's Circular nor a
+ Patent Broker's Advertisement. No advertisements of any
+ description appear in the work. It is a book containing a
+ quarter of a century's experience of a successful inventor,
+ together with notes based upon the experience of many other
+ inventors.
+
+ Among the subjects treated in this work are: How to Invent. How
+ to Secure a Good Patent. Value of Good Invention. How to Exhibit
+ an Invention. How to Interest Capital. How to Estimate the Value
+ of a Patent. Value of Design Patents. Value of Foreign Patents.
+ Value of Small Inventions. Advice on Selling Patents. Advice on
+ the Formation of Stock Companies. Advice on the Formation of
+ Limited Liability Companies. Advice on Disposing of Old Patents.
+ Advice as to Patent Attorneys. Advice as to Selling Agents.
+ Forms of Assignments. License and Contracts. State Laws
+ Concerning Patent Rights. 1900 Census of the United States by
+ Counts of Over 10,000 Population. Revised Edition. 120 pages.
+ Price =$1.00=
+
+
+~KNOTS~
+
+
+=Knots, Splices and Rope Work.= By A. HYATT VERRILL.
+
+ This is a practical book giving complete and simple directions
+ for making all the most useful and ornamental knots in common
+ use, with chapters on Splicing, Pointing, Seizing, Serving, etc.
+ This book is fully illustrated with 154 original engravings,
+ which show how each knot, tie or splice is formed, and its
+ appearance when finished. The book will be found of the greatest
+ value to Campers, Yachtsmen, Travelers, Boy Scouts, in fact, to
+ anyone having occasion to use or handle rope or knots for any
+ purpose. The book is thoroughly reliable and practical, and is
+ not only a guide, but a teacher. It is the standard work on the
+ subject. Among the contents are: 1. Cordage, Kinds of Rope.
+ Construction of Rope, Parts of Rope Cable and Bolt Rope.
+ Strength of Rope, Weight of Rope. 2. Simple Knots and Bends.
+ Terms Used in Handling Rope. Seizing Rope. 3. Ties and Hitches.
+ 4. Noose, Loops and Mooring Knots. 5. Shortenings, Grommets and
+ Salvages. 6. Lashings, Seizings and Splices. 7. Fancy Knots and
+ Rope Work. 128 pages, 150 original engravings. 2nd Revised
+ Edition. Price =75 cents=
+
+
+~LATHE WORK~
+
+
+=Lathe Design, Construction, and Operation, with Practical Examples of
+Lathe Work.= By OSCAR E. PERRIGO.
+
+ A new, revised edition, and the only complete American work on
+ the subject, written by a man who knows not only how work ought
+ to be done, but who also knows how to do it, and how to convey
+ this knowledge to others. It is strictly up-to-date in its
+ descriptions and illustrations. Lathe history and the relations
+ of the lathe to manufacturing are given; also a description of
+ the various devices for feeds and thread-cutting mechanisms from
+ early efforts in this direction to the present time. Lathe
+ design is thoroughly discussed, including back gearing, driving
+ cones, thread-cutting gears, and all the essential elements of
+ the modern lathe. The classification of lathes is taken up,
+ giving the essential differences of the several types of lathes
+ including, as is usually understood, engine lathes, bench
+ lathes, speed lathes, forge lathes, gap lathes, pulley lathes,
+ forming lathes, multiple-spindle lathes, rapid-reduction lathes,
+ precision lathes, turret lathes, special lathes, electrically
+ driven lathes, etc. In addition to the complete exposition on
+ construction and design, much practical matter on lathe
+ installation, care and operation has been incorporated in the
+ enlarged new edition. All kinds of lathe attachments for
+ drilling, milling, etc., are described and complete instructions
+ are given to enable the novice machinist to grasp the art of
+ lathe operation as well as the principles involved in design. A
+ number of difficult machining operations are described at length
+ and illustrated. The new edition has nearly 500 pages and 350
+ illustrations. Price =$2.50=
+
+ WHAT IS SAID OF THIS BOOK:
+
+ "This is a lathe book from beginning to end, and is just the
+ kind of a book which one delights to consult--a masterly
+ treatment of the subject in hand."--_Engineering News._
+
+ "This work will be of exceptional interest to any one who is
+ interested in lathe practice, as one very seldom sees such a
+ complete treatise on a subject as this is on the
+ lathe."--_Canadian Machinery._
+
+
+=Practical Metal Turning.= By JOSEPH G. HORNER.
+
+ A work of 404 pages, fully illustrated, covering in a
+ comprehensive manner the modern practice of machining metal
+ parts in the lathe, including the regular engine lathe, its
+ essential design, its uses, its tools, its attachments, and the
+ manner of holding the work and performing the operations. The
+ modernized engine lathe, its methods, tools and great range of
+ accurate work. The turret lathe, its tools, accessories and
+ methods of performing its functions. Chapters on special work,
+ grinding, tool holders, speeds, feeds, modern tool steels, etc.
+ Second edition =$3.50=
+
+
+=Turning and Boring Tapers.= By FRED H. COLVIN.
+
+ There are two ways to turn tapers; the right way and one other.
+ This treatise has to do with the right way; it tells you how to
+ start the work properly, how to set the lathe, what tools to use
+ and how to use them, and forty and one other little things that
+ you should know. Fourth edition =25 cents=
+
+
+~LIQUID AIR~
+
+
+=Liquid Air and the Liquefaction of Gases.= By T. O'CONOR SLOANE.
+
+ This book gives the history of the theory, discovery and
+ manufacture of Liquid Air, and contains an illustrated
+ description of all the experiments that have excited the wonder
+ of audiences all over the country. It shows how liquid air, like
+ water, is carried hundreds of miles and is handled in open
+ buckets. It tells what may be expected from it in the near
+ future.
+
+ A book that renders simple one of the most perplexing chemical
+ problems of the century. Startling developments illustrated by
+ actual experiments.
+
+ It is not only a work of scientific interest and authority, but
+ is intended for the general reader, being written in a popular
+ style--easily understood by every one. Second edition. 365
+ pages. Price =$2.00=
+
+
+~LOCOMOTIVE ENGINEERING~
+
+
+=Air-Brake Catechism.= By ROBERT H. BLACKALL.
+
+ This book is a standard text-book. It covers the Westinghouse
+ Air-Brake Equipment, including the No. 5 and the No. 6 E.-T.
+ Locomotive Brake Equipment; the K (Quick Service) Triple Valve
+ for Freight Service; and the Cross-Compound Pump. The operation
+ of all parts of the apparatus is explained in detail, and a
+ practical way of finding their peculiarities and defects, with a
+ proper remedy, is given. It contains 2,000 questions with their
+ answers, which will enable any railroad man to pass any
+ examination on the subject of Air Brakes. Endorsed and used by
+ air-brake instructors and examiners on nearly every railroad in
+ the United States. Twenty-sixth edition. 411 pages, fully
+ illustrated with colored plates and diagrams. Price =$2.00=
+
+
+=American Compound Locomotives.= By FRED H. COLVIN.
+
+ The only book on compounds for the engineman or shopman that
+ shows in a plain, practical way the various features of compound
+ locomotives in use. Shows how they are made, what to do when
+ they break down or balk. Contains sections as follows: A Bit of
+ History. Theory of Compounding Steam Cylinders. Baldwin
+ Two-Cylinder Compound. Pittsburg Two-Cylinder Compound. Rhode
+ Island Compound. Richmond Compound. Rogers Compound. Schenectady
+ Two-Cylinder Compound. Vauclain Compound. Tandem Compounds.
+ Baldwin Tandem. The Colvin-Wightman Tandem. Schenectady Tandem.
+ Balanced Locomotives. Baldwin Balanced Compound. Plans for
+ Balancing. Locating Blows. Breakdowns. Reducing Valves.
+ Drifting. Valve Motion. Disconnecting. Power of Compound
+ Locomotives. Practical Notes.
+
+ Fully illustrated and containing ten special "Duotone" inserts
+ on heavy Plate Paper, showing different types of Compounds. 142
+ pages. Price =$1.00=
+
+
+=Application of Highly Superheated Steam to Locomotives.= By ROBERT
+GARBE.
+
+ A practical book which cannot be recommended too highly to those
+ motive-power men who are anxious to maintain the highest
+ efficiency in their locomotives. Contains special chapters on
+ Generation of Highly Superheated Steam; Superheated Steam and
+ the Two-Cylinder Simple Engine; Compounding and Superheating;
+ Designs of Locomotive Superheaters; Constructive Details of
+ Locomotives Using Highly Superheated Steam. Experimental and
+ Working Results. Illustrated with folding plates and tables.
+ Cloth. Price =$2.50=
+
+
+=Combustion of Coal and the Prevention of Smoke.= By WM. M. BARR.
+
+ This book has been prepared with special reference to the
+ generation of heat by the combustion of the common fuels found
+ in the United States and deals particularly with the conditions
+ necessary to the economic and smokeless combustion of bituminous
+ coal in Stationary and Locomotive Steam Boilers.
+
+ Presentation of this important subject is systematic and
+ progressive. The arrangement of the book is in a series of
+ practical questions to which are appended accurate answers,
+ which describe in language free from technicalities the several
+ processes involved in the furnace combustion of American fuels;
+ it clearly states the essential requisites for perfect
+ combustion, and points out the best methods of furnace
+ construction for obtaining the greatest quantity of heat from
+ any given quality of coal. Nearly 350 pages, fully illustrated.
+ Price =$1.00=
+
+
+=Diary of a Round-House Foreman.= By T. S. REILLY.
+
+ This is the greatest book of railroad experiences ever
+ published. Containing a fund of information and suggestions
+ along the line of handling men, organizing, etc., that one
+ cannot afford to miss. 176 pages. Price =$1.00=
+
+
+=Link Motions, Valves and Valve Setting.= By FRED H. COLVIN, Associate
+Editor of "American Machinist."
+
+ A handy book for the engineer or machinist that clears up the
+ mysteries of valve setting. Shows the different valve gears in
+ use, how they work, and why. Piston and slide valves of
+ different types are illustrated and explained. A book that every
+ railroad man in the motive-power department ought to have.
+ Contains chapters on Locomotive Link Motion, Valve Movements,
+ Setting Slide Valves, Analysis by Diagrams, Modern Practice,
+ Slip of Block, Slice Valves, Piston Valves, Setting Piston
+ Valves, Joy-Allen Valve Gear, Walschaert Valve Gear, Gooch Valve
+ Gear, Alfree-Hubbell Valve Gear, etc., etc. Fully illustrated.
+ Price =50 cents=
+
+
+=Locomotive Boiler Construction.= By FRANK A. KLEINHANS.
+
+ The construction of boilers in general is treated and, following
+ this, the locomotive boiler is taken up in the order in which
+ its various parts go through the shop. Shows all types of
+ boilers used; gives details of construction; practical facts,
+ such as life of riveting, punches and dies; work done per day,
+ allowance for bending and flanging sheets and other data.
+ Including the recent Locomotive Boiler Inspection Laws and
+ Examination Questions with their answers for Government
+ Inspectors. Contains chapters on Laying-Out Work; Flanging and
+ Forging; Punching; Shearing; Plate Planing; General Tables;
+ Finishing Parts; Bending; Machinery Parts; Riveting; Boiler
+ Details; Smoke-Box Details; Assembling and Calking; Boiler-Shop
+ Machinery, etc., etc.
+
+ There isn't a man who has anything to do with boiler work,
+ either new or repair work, who doesn't need this book. The
+ manufacturer, superintendent, foreman and boiler worker--all
+ need it. No matter what the type of boiler, you'll find a mint
+ of information that you wouldn't be without. Over 400 pages,
+ five large folding plates. Price =$3.00=
+
+
+=Locomotive Breakdowns and their Remedies.= By GEO. L. FOWLER. Revised
+by WM. W. WOOD, Air-Brake Instructor. Just issued. Revised pocket
+edition.
+
+ It is out of the question to try and tell you about every
+ subject that is covered in this pocket edition of Locomotive
+ Breakdowns. Just imagine all the common troubles that an
+ engineer may expect to happen some time, and then add all of the
+ unexpected ones, troubles that could occur, but that you have
+ never thought about, and you will find that they are all treated
+ with the very best methods of repair. Walschaert Locomotive
+ Valve Gear Troubles, Electric Headlight Troubles, as well as
+ Questions and Answers on the Air Brake are all included. 312
+ pages. 8th Revised Edition. Fully illustrated. Price =$1.00=
+
+
+=Locomotive Catechism.= By ROBERT GRIMSHAW.
+
+ The revised edition of "Locomotive Catechism," by Robert
+ Grimshaw, is a New Book from Cover to Cover. It contains twice
+ as many pages and double the number of illustrations of previous
+ editions. Includes the greatest amount of practical information
+ ever published on the construction and management of modern
+ locomotives. Specially Prepared Chapters on the Walschaert
+ Locomotive Valve Gear, the Air-Brake Equipment and the Electric
+ Headlight are given.
+
+ It commends itself at once to every Engineer and Fireman, and to
+ all who are going in for examination or promotion. In plain
+ language, with full, complete answers, not only all the
+ questions asked by the examining engineer are given, but those
+ which the young and less experienced would ask the veteran, and
+ which old hands ask as "stickers." It is a veritable
+ Encyclopedia of the Locomotive, is entirely free from
+ mathematics, easily understood and thoroughly up to date.
+ Contains over 4,000 Examination Questions with their Answers.
+ 825 pages, 437 illustrations, and 3 folding plates. 28th Revised
+ Edition. Price =$2.50=
+
+
+=Practical Instructor and Reference Book for Locomotive Firemen and
+Engineers.= By CHAS. F. LOCKHART.
+
+ An entirely new book on the Locomotive. It appeals to every
+ railroad man, as it tells him how things are done and the right
+ way to do them. Written by a man who has had years of practical
+ experience in locomotive shops and on the road firing and
+ running. The information given in this book cannot be found in
+ any other similar treatise. Eight hundred and fifty-one
+ questions with their answers are included, which will prove
+ specially helpful to those preparing for examination. Practical
+ information on: The Construction and Operation of Locomotives,
+ Breakdowns and their Remedies, Air Brakes and Valve Gears. Rules
+ and Signals are handled in a thorough manner. As a book of
+ reference it cannot be excelled. The book is divided into six
+ parts, as follows: 1. The Fireman's Duties. 2. General
+ Description of the Locomotive. 3. Breakdowns and their Remedies.
+ 4. Air Brakes. 5. Extracts from Standard Rules. 6. Questions for
+ Examination. The 851 questions have been carefully selected and
+ arranged. These cover the examinations required by the different
+ railroads. 368 pages, 88 illustrations. Price =$1.50=
+
+
+=Prevention of Railroad Accidents, or Safety in Railroading.= By GEORGE
+BRADSHAW.
+
+ This book is a heart-to-heart talk with Railroad Employees,
+ dealing with facts, not theories, and showing the men in the
+ ranks, from every-day experience, how accidents occur and how
+ they may be avoided. The book is illustrated with seventy
+ original photographs and drawings showing the safe and unsafe
+ methods of work. No visionary schemes, no ideal pictures. Just
+ Plain Facts and Practical Suggestions are given. Every railroad
+ employee who reads the book is a better and safer man to have in
+ railroad service. It gives just the information which will be
+ the means of preventing many injuries and deaths. All railroad
+ employees should procure a copy, read it, and do their part in
+ preventing accidents. 169 pages. Pocket size. Fully illustrated.
+ Price =50 cents=
+
+
+=Train Rule Examinations Made Easy.= By G. E. COLLINGWOOD.
+
+ This is the only practical work on train rules in print. Every
+ detail is covered, and puzzling points are explained in simple,
+ comprehensive language, making it a practical treatise for the
+ Train Dispatcher, Engineman, Trainman, and all others who have
+ to do with the movements of trains. Contains complete and
+ reliable information of the Standard Code of Train Rules for
+ single track. Shows Signals in Colors, as used on the different
+ roads. Explains fully the practical application of train orders,
+ giving a clear and definite understanding of all orders which
+ may be used. The meaning and necessity for certain rules are
+ explained in such a manner that the student may know beyond a
+ doubt the rights conferred under any orders he may receive or
+ the action required by certain rules. As nearly all roads
+ require trainmen to pass regular examinations, a complete set of
+ examination questions, with their answers, are included. These
+ will enable the student to pass the required examinations with
+ credit to himself and the road for which he works. 2nd Edition,
+ Revised. 256 pages, fully illustrated, with Train Signals in
+ Colors. Price =$1.25=
+
+
+=The Walschaert and Other Modern Radial Valve Gears for Locomotives.= By
+WM. W. WOOD.
+
+ If you would thoroughly understand the Walschaert Valve Gear you
+ should possess a copy of this book, as the author takes the
+ plainest form of a steam engine--a stationary engine in the
+ rough, that will only turn its crank in one direction--and from
+ it builds up, with the reader's help, a modern locomotive
+ equipped with the Walschaert Valve Gear, complete. The points
+ discussed are clearly illustrated: Two large folding plates that
+ show the positions of the valves of both inside or outside
+ admission type, as well as the links and other parts of the gear
+ when the crank is at nine different points in its revolution,
+ are especially valuable in making the movement clear. These
+ employ sliding cardboard models which are contained in a pocket
+ in the cover.
+
+ The book is divided into five general divisions, as follows: 1.
+ Analysis of the gear. 2. Designing and erecting the gear. 3.
+ Advantages of the gear. 4. Questions and answers relating to the
+ Walschaert Valve Gear. 5. Setting valves with the Walschaert
+ Valve Gear; the three primary types of locomotive valve motion;
+ modern radial valve gears other than the Walschaert; the Hobart
+ All-free Valve and Valve Gear, with questions and answers on
+ breakdowns; the Baker-Pilliod Valve Gear; the Improved
+ Baker-Pilliod Valve Gear, with questions and answers on
+ breakdowns.
+
+ The questions with full answers given will be especially
+ valuable to firemen and engineers in preparing for an
+ examination for promotion. 245 pages. 3rd Revised Edition. Price
+ =$1.50=
+
+
+=Westinghouse E-T Air-Brake Instruction Pocket Book.= By WM. W. WOOD,
+Air-Brake Instructor.
+
+ Here is a book for the railroad man, and the man who aims to be
+ one. It is without doubt the only complete work published on the
+ Westinghouse E-T Locomotive Brake Equipment. Written by an
+ Air-Brake Instructor who knows just what is needed. It covers
+ the subject thoroughly. Everything about the New Westinghouse
+ Engine and Tender Brake Equipment, including the standard No. 5
+ and the Perfected No. 6 style of brake, is treated in detail.
+ Written in plain English and profusely illustrated with Colored
+ Plates, which enable one to trace the flow of pressures
+ throughout the entire equipment. The best book ever published on
+ the Air Brake. Equally good for the beginner and the advanced
+ engineer. Will pass any one through any examination. It informs
+ and enlightens you on every point. Indispensable to every
+ engineman and trainman.
+
+ Contains examination questions and answers on the E-T equipment.
+ Covering what the E-T Brake is. How it should be operated. What
+ to do when defective. Not a question can be asked of the
+ engineman up for promotion, on either the No. 5 or the No. 6 E-T
+ equipment, that is not asked and answered in the book. If you
+ want to thoroughly understand the E-T equipment get a copy of
+ this book. It covers every detail. Makes Air-Brake troubles and
+ examinations easy. Price =$1.50=
+
+
+~MACHINE-SHOP PRACTICE~
+
+
+=American Tool Making and Interchangeable Manufacturing.= By J. V.
+WOODWORTH.
+
+ A "shoppy" book, containing no theorizing, no problematical or
+ experimental devices. There are no badly proportioned and
+ impossible diagrams, no catalogue cuts, but a valuable
+ collection of drawings and descriptions of devices, the rich
+ fruits of the author's own experience. In its 500-odd pages the
+ one subject only, Tool Making, and whatever relates thereto, is
+ dealt with. The work stands without a rival. It is a complete,
+ practical treatise, on the art of American Tool Making and
+ system of interchangeable manufacturing as carried on to-day in
+ the United States. In it are described and illustrated all of
+ the different types and classes of small tools, fixtures,
+ devices, and special appliances which are in general use in all
+ machine-manufacturing and metal-working establishments where
+ economy, capacity, and interchangeability in the production of
+ machined metal parts are imperative. The science of jig making
+ is exhaustively discussed, and particular attention is paid to
+ drill jigs, boring, profiling and milling fixtures and other
+ devices in which the parts to be machined are located and
+ fastened within the contrivances. All of the tools, fixtures,
+ and devices illustrated and described have been or are used for
+ the actual production of work, such as parts of drill presses,
+ lathes, patented machinery, typewriters, electrical apparatus,
+ mechanical appliances, brass goods, composition parts, mould
+ products, sheet-metal articles, drop-forgings, jewelry, watches,
+ medals, coins, etc. 531 pages. Price =$4.00=
+
+
+=HENLEY'S ENCYCLOPEDIA OF PRACTICAL ENGINEERING AND ALLIED TRADES.=
+EDITED by JOSEPH G. HORNER, A.M.I., M.E.
+
+ This set of five volumes contains about 2,500 pages with
+ thousands of illustrations, including diagrammatic and sectional
+ drawings with full explanatory details. This work covers the
+ entire practice of Civil and Mechanical Engineering. The best
+ known experts in all branches of engineering have contributed to
+ these volumes. The Cyclopedia is admirably well adapted to the
+ needs of the beginner and the self-taught practical man, as well
+ as the mechanical engineer, designer, draftsman, shop
+ superintendent, foreman, and machinist. The work will be found a
+ means of advancement to any progressive man. It is encyclopedic
+ in scope, thorough and practical in its treatment on technical
+ subjects, simple and clear in its descriptive matter, and
+ without unnecessary technicalities or formulae. The articles are
+ as brief as may be and yet give a reasonably clear and explicit
+ statement of the subject, and are written by men who have had
+ ample practical experience in the matters of which they write.
+ It tells you all you want to know about engineering and tells it
+ so simply, so clearly, so concisely, that one cannot help but
+ understand. As a work of reference it is without a peer.
+ Complete set of five volumes, price =$25.00=
+
+
+=The Modern Machinist.= By JOHN T. USHER.
+
+ This is a book, showing by plain description and by profuse
+ engravings made expressly for the work, all that is best, most
+ advanced, and of the highest efficiency in modern machine-shop
+ practice, tools and implements, showing the way by which and
+ through which, as Mr. Maxim says "American machinists have
+ become and are the finest mechanics in the world." Indicating as
+ it does, in every line, the familiarity of the author with every
+ detail of daily experience in the shop, it cannot fail to be of
+ service to any man practically connected with the shaping or
+ finishing of metals.
+
+ There is nothing experimental or visionary about the book, all
+ devices being in actual use and giving good results. It might be
+ called a compendium of shop methods, showing a variety of
+ special tools and appliances which will give new ideas to many
+ mechanics, from the superintendent down to the man at the bench.
+ It will be found a valuable addition to any machinist's library,
+ and should be consulted whenever a new or difficult job is to be
+ done, whether it is boring, milling, turning, or planing, as
+ they are all treated m a practical manner. Fifth edition. 320
+ pages. 250 illustrations. Price =$2.50=
+
+
+=THE WHOLE FIELD OF MECHANICAL MOVEMENTS COVERED BY MR. HISCOX'S TWO
+BOOKS=
+
+ _We publish two books by Gardner D. Hiscox that will keep you
+ from "inventing" things that have been done before, and suggest
+ ways of doing things that you have not thought of before. Many a
+ man spends time and money pondering over some mechanical
+ problem, only to learn, after he has solved the problem, that
+ the same thing has been accomplished and put in practice by
+ others long before. Time and money spent in an effort to
+ accomplish what has already been accomplished are time and money
+ LOST. The whole field of mechanics, every known mechanical
+ movement, and practically every device are covered by these two
+ books. If the thing you want has been invented, it is
+ illustrated in them. If it hasn't been invented, then you'll
+ find in them the nearest things to what you want, some movements
+ or devices that will apply in your case, perhaps; or which will
+ give you a key from which to work. No book or set of books ever
+ published is of more real value to the Inventor, Draftsman, or
+ practical Mechanic than the two volumes described below._
+
+
+=Mechanical Movements, Powers, and Devices.= By GARDNER D. HISCOX.
+
+ This is a collection of 1,890 engravings of different mechanical
+ motions and appliances, accompanied by appropriate text, making
+ it a book of great value to the inventor, the draftsman, and to
+ all readers with mechanical tastes. The book is divided into
+ eighteen sections or chapters, in which the subject-matter is
+ classified under the following heads: Mechanical Powers;
+ Transmission of Power; Measurement of Power; Steam Power; Air
+ Power Appliances; Electric Power and Construction; Navigation
+ and Roads; Gearing; Motion and Devices; Controlling Motion;
+ Horological; Mining; Mill and Factory Appliances; Construction
+ and Devices; Drafting Devices; Miscellaneous Devices, etc. 15th
+ Edition. 400 octavo pages. Price =$3.00=
+
+
+=Mechanical Appliances, Mechanical Movements and Novelties of
+Construction.= By GARDNER D. HISCOX.
+
+ This is a supplementary volume to the one upon mechanical
+ movements. Unlike the first volume, which is more elementary in
+ character, this volume contains illustrations and descriptions
+ of many combinations of motions and of mechanical devices and
+ appliances found in different lines of machinery, each device
+ being shown by a line drawing with a description showing its
+ working parts and the method of operation. From the multitude of
+ devices described and illustrated might be mentioned, in
+ passing, such items as conveyors and elevators, Pony brakes,
+ thermometers, various types of boilers, solar engines, oil-fuel
+ burners, condensers, evaporators, Corliss and other valve gears,
+ governors, gas engines, water motors of various descriptions,
+ air ships, motors and dynamos, automobile and motor bicycles,
+ railway lock signals, car couplers, link and gear motions, ball
+ bearings, breech-block mechanism for heavy guns, and a large
+ accumulation of others of equal importance. One thousand
+ specially made engravings. 396 octavo pages. Fourth edition.
+ Price =$3.00=
+
+
+=Machine-Shop Tools and Shop Practice.= By W. H. VANDERVOORT.
+
+ A work of 555 pages and 673 illustrations, describing in every
+ detail the construction, operation and manipulation of both hand
+ and machine tools. Includes chapters on filing, fitting and
+ scraping surfaces; on drills, reamers, taps and dies; the lathe
+ and its tools: planers, shapers, and their tools; milling
+ machines and cutters; gear cutters and gear cutting; drilling
+ machines and drill work; grinding machines and their work;
+ hardening and tempering; gearing, belting and transmission
+ machinery; useful data and tables. Sixth edition. Price =$3.00=
+
+
+=Machine-Shop Arithmetic.= By COLVIN-CHENEY.
+
+ This is an arithmetic of the things you have to do with daily.
+ It tells you plainly about: how to find areas in figures; how to
+ find surface or volume of balls or spheres; handy ways for
+ calculating; about compound gearing; cutting screw threads on
+ any lathe; drilling for taps; speeds of drills; taps, emery
+ wheels, grindstones, milling cutters, etc.; all about the Metric
+ system with conversion tables; properties of metals; strength of
+ bolts and nuts; decimal equivalent of an inch. All sorts of
+ machine-shop figuring and 1,001 other things, any one of which
+ ought to be worth more than the price of this book to you, as it
+ saves you the trouble of bothering the boss. 6th Edition. 131
+ pages. Price =50 cents=
+
+
+=Modern Machine-Shop Construction, Equipment and Management.= By OSCAR
+E. PERRIGO.
+
+ The only work published that describes the Modern Shop or
+ Manufacturing Plant from the time the grass is growing on the
+ site intended for it until the finished product is shipped. Just
+ the book needed by those contemplating the erection of modern
+ shop buildings, the rebuilding and reorganization of old ones,
+ or the introduction of Modern Shop Methods, time and cost
+ systems. It is a book written and illustrated by a practical
+ shop man for practical shop men who are too busy to read
+ theories and want facts. It is the most complete all-round book
+ of its kind ever published. Second Edition, Revised. 384 large
+ quarto pages. 219 original and specially made illustrations. 2nd
+ Revised and Enlarged Edition. Price =$5.00=
+
+
+=Modern Milling Machines: Their Design, Construction, and Operation.= By
+JOSEPH G. HORNER.
+
+ This book describes and illustrates the Milling Machine and its
+ work in such a plain, clear and forceful manner, and illustrates
+ the subject so clearly and completely, that the up-to-date
+ machinist, student or mechanical engineer cannot afford to do
+ without the valuable information which it contains. It describes
+ not only the early machines of this class, but notes their
+ gradual development into the splendid machines of the present
+ day, giving the design and construction of the various types,
+ forms, and special features produced by prominent manufacturers,
+ American and foreign. 304 pages, 300 illustrations. Cloth. Price
+ =$4.00=
+
+
+="Shop Kinks."= By ROBERT GRIMSHAW.
+
+ A book of 400 pages and 222 illustrations, being entirely
+ different from any other book on machine-shop practice.
+ Departing from conventional style, the author avoids universal
+ or common shop usage and limits his work to showing special ways
+ of doing things better, more cheaply and more rapidly than
+ usual. As a result the advanced methods of representative
+ establishments of the world are placed at the disposal of the
+ reader. This book shows the proprietor where large savings are
+ possible, and how products may be improved. To the employee it
+ holds out suggestions that, properly applied, will hasten his
+ advancement. No shop can afford to be without it. It bristles
+ with valuable wrinkles and helpful suggestions. It will benefit
+ all, from apprentice to proprietor. Every machinist, at any age,
+ should study its pages. Fifth edition. Price =$2.50=
+
+
+=Threads and Thread Cutting.= By COLVIN and STABEL.
+
+ This clears up many of the mysteries of thread-cutting, such as
+ double and triple threads, internal threads, catching threads,
+ use of hobs, etc. Contains a lot of useful hints and several
+ tables. Third edition. Price =25 cents=
+
+
+~MANUAL TRAINING~
+
+
+=Economics of Manual Training.= By LOUIS ROUILLION.
+
+ The only book published that gives just the information needed
+ by all interested in Manual Training, regarding Buildings,
+ Equipment, and Supplies. Shows exactly what is needed for all
+ grades of the work from the Kindergarten to the High and Normal
+ School. Gives itemized lists of everything used in Manual
+ Training Work and tells just what it ought to cost. Also shows
+ where to buy supplies, etc. Contains 174 pages, and is fully
+ illustrated. Second edition. Price =$1.50=
+
+
+~MARINE ENGINEERING~
+
+
+=The Naval Architect's and Shipbuilder's Pocket Book of Formulae, Rules,
+and Tables and Marine Engineer's and Surveyor's Handy Book of
+Reference.= By CLEMENT MACKROW and LLOYD WOOLLARD.
+
+ The eleventh Revised and Enlarged Edition of this most
+ comprehensive work has just been issued. It is absolutely
+ indispensable to all engaged in the Shipbuilding Industry, as it
+ condenses into a compact form all data and formulae that are
+ ordinarily required. The book is completely up to date,
+ including among other subjects a section on Aeronautics. 750
+ pages, limp leather binding. Price =$5.00 net=
+
+
+=Marine Engines and Boilers: Their Design and Construction.= By DR. G.
+BAUER, LESLIE S. ROBERTSON and S. BRYAN DONKIN.
+
+ In the words of Dr. Bauer, the present work owes its origin to
+ an oft felt want of a condensed treatise embodying the
+ theoretical and practical rules used in designing marine engines
+ and boilers. The need of such a work has been felt by most
+ engineers engaged in the construction and working of marine
+ engines, not only by the younger men, but also by those of
+ greater experience. The fact that the original German work was
+ written by the chief engineer of the famous Vulcan Works,
+ Stettin, is in itself a guarantee that this book is in all
+ respects thoroughly up-to-date, and that it embodies all the
+ information which is necessary for the design and construction
+ of the highest types of marine engines and boilers. It may be
+ said that the motive power which Dr. Bauer has placed in the
+ fast German liners that have been turned out of late years from
+ the Stettin Works represent the very best practice in marine
+ engineering of the present day. The work is clearly written,
+ thoroughly systematic, theoretically sound; while the character
+ of the plans, drawings, tables, and statistics is without
+ reproach. The illustrations are careful reproductions from
+ actual working drawings, with some well-executed photographic
+ views of completed engines and boilers. 744 pages, 550
+ illustrations and numerous tables. Cloth. Price =$9.00 net=
+
+
+~MINING~
+
+
+=Ore Deposits, with a Chapter on Hints to Prospectors.= By J. P.
+JOHNSON.
+
+ This book gives a condensed account of the ore deposits at
+ present known in South Africa. It is also intended as a guide to
+ the prospector. Only an elementary knowledge of geology and some
+ mining experience are necessary in order to understand this
+ work. With these qualifications, it will materially assist one
+ in his search for metalliferous mineral occurrences and, so far
+ as simple ores are concerned, should enable one to form some
+ idea of the possibilities of any he may find. Illustrated.
+ Cloth. Price =$2.00=
+
+
+=Practical Coal Mining.= By T. H. COCKIN.
+
+ An important work, containing 428 pages and 213 illustrations,
+ complete with practical details, which will intuitively impart
+ to the reader not only a general knowledge of the principles of
+ coal mining, but also considerable insight into allied subjects.
+ The treatise is positively up-to-date in every instance, and
+ should be in the hands of every colliery engineer, geologist,
+ mine operator, superintendent, foreman, and all others who are
+ interested in or connected with the industry. 3d Edition. Cloth.
+ Price =$2.50=
+
+
+=Physics and Chemistry of Mining.= By T. H. BYROM.
+
+ A practical work for the use of all preparing for examinations
+ in mining or qualifying for colliery managers' certificates. The
+ aim of the author in this excellent book is to place clearly
+ before the reader useful and authoritative data which will
+ render him valuable assistance in his studies. The only work of
+ its kind published. The information incorporated in it will
+ prove of the greatest practical utility to students, mining
+ engineers, colliery managers, and all others who are specially
+ interested in the present-day treatment of mining problems. 160
+ pages, illustrated. Price =$2.00=
+
+
+~PATTERN MAKING~
+
+
+=Practical Pattern Making.= By F. W. BARROWS.
+
+ This book, now in its second edition, is a comprehensive and
+ entirely practical treatise on the subject of pattern making,
+ illustrating pattern work in both wood and metal, and with
+ definite instructions on the use of plaster of paris in the
+ trade. It gives specific and detailed descriptions of the
+ materials used by pattern makers, and describes the tools, both
+ those for the bench and the more interesting machine tools,
+ having complete chapters on the Lathe, the Circular Saw, and the
+ Band Saw. It gives many examples of pattern work, each one fully
+ illustrated and explained with much detail. These examples, in
+ their great variety, offer much that will be found of interest
+ to all pattern makers, and especially to the younger ones, who
+ are seeking information on the more advanced branches of their
+ trade.
+
+ In this second edition of the work will be found much that is
+ new, even to those who have long practised this exacting trade.
+ In the description of patterns as adapted to the Moulding
+ Machine many difficulties which have long prevented the rapid
+ and economical production of castings are overcome; and this
+ great, new branch of the trade is given much space. Stripping
+ plate and stool plate work and the less expensive vibrator, or
+ rapping plate work, are all explained in detail.
+
+ Plain, every-day rules for lessening the cost of patterns, with
+ a complete system of cost keeping, a detailed method of marking,
+ applicable to all branches of the trade, with complete
+ information showing what the pattern is, its specific title, its
+ cost, date of production, material of which it is made, the
+ number of pieces and core-boxes, and its location in the pattern
+ safe, all condensed into a most complete card record, with cross
+ index. The book closes with an original and practical method for
+ the inventory and valuation of patterns. Containing nearly 350
+ pages and 170 illustrations. Price =$2.00=
+
+
+~PERFUMERY~
+
+
+=Perfumes and Cosmetics: Their Preparation and Manufacture.= By G. W.
+ASKINSON, Perfumer.
+
+ A comprehensive treatise, in which there has been nothing
+ omitted that could be of value to the perfumer or manufacturer
+ of toilet preparations. Complete directions for making
+ handkerchief perfumes, smelling-salts, sachets, fumigating
+ pastilles; preparations for the care of the skin, the mouth, the
+ hair, cosmetics, hair dyes and other toilet articles are given,
+ also a detailed description of aromatic substances; their
+ nature, tests of purity, and wholesome manufacture, including a
+ chapter on synthetic products, with formulas for their use. A
+ book of general as well as professional interest, meeting the
+ wants not only of the druggist and perfume manufacturer, but
+ also of the general public. Among the contents are: 1. The
+ History of Perfumery. 2. About Aromatic Substances in General.
+ 3. Odors from the Vegetable Kingdom. 4. The Aromatic Vegetable
+ Substances Employed in Perfumery. 5. The Animal Substances Used
+ in Perfumery. 6. The Chemical Products Used in Perfumery. 7. The
+ Extraction of Odors. 8. The Special Characteristics of Aromatic
+ Substances. 9 The Adulteration of Essential Oils and Their
+ Recognition. 10. Synthetic Products. 11. Table of Physical
+ Properties of Aromatic Chemicals. 12. The Essences or Extracts
+ Employed in Perfumery. 13. Directions for Making the Most
+ Important Essences and Extracts. 14. The Division of Perfumery.
+ 15. The Manufacture of Handkerchief Perfumes. 16. Formulas for
+ Handkerchief Perfumes. 17. Ammoniacal and Acid Perfumes. 18. Dry
+ Perfumes. 19. Formulas for Dry Perfumes. 20. The Perfumes Used
+ for Fumigation. 21. Antiseptic and Therapeutic Value of
+ Perfumes. 22. Classification of Odors. 23. Some Special
+ Perfumery Products. 24. Hygiene and Cosmetic Perfumery. 25.
+ Preparations for the Care of the Skin. 26. Manufacture of
+ Casein. 27. Formulas for Emulsions. 28. Formulas for Cream. 29.
+ Formulas for Meals, Pastes and Vegetable Milk. 30. Preparations
+ Used for the Hair. 31. Formulas for Hair Tonics and Restorers.
+ 32. Pomades and Hair Oils 33. Formulas for the Manufacture of
+ Pomades and Hair Oils. 34. Hair Dyes and Depilatories. 35. Wax
+ Pomades, Bandolines and Brilliantines. 36. Skin Cosmetics and
+ Face Lotions. 37. Preparations for the Nails. 38. Water
+ Softeners and Bath Salts. 39. Preparations for the Care of the
+ Mouth. 40. The Colors Used in Perfumery. 41. The Utensils Used
+ in the Toilet. Fourth edition, much enlarged and brought up to
+ date. Nearly 400 pages, illustrated. Price =$5.00=
+
+ WHAT IS SAID OF THIS BOOK:
+
+ "The most satisfactory work on the subject of Perfumery that we
+ have ever seen."
+
+ "We feel safe in saying that here is a book on Perfumery that
+ will not disappoint you, for it has practical and excellent
+ formulae that are within your ability to prepare readily."
+
+ "We recommend the volume as worthy of confidence, and say that
+ no purchaser will be disappointed in securing from its pages
+ good value for its cost, and a large dividend on the same, even
+ if he should use but one per cent. of its working formulae. There
+ is money in it for every user of its
+ information."--_Pharmaceutical Record._
+
+
+~PLUMBING~
+
+
+=Mechanical Drawing for Plumbers.= By R. M. STARBUCK.
+
+ A concise, comprehensive and practical treatise on the subject
+ of mechanical drawing in its various modern applications to the
+ work of all who are in any way connected with the plumbing
+ trade. Nothing will so help the plumber in estimating and in
+ explaining work to customers and workmen as a knowledge of
+ drawing, and to the workman it is of inestimable value if he is
+ to rise above his position to positions of greater
+ responsibility. Among the chapters contained are: 1. Value to
+ plumber of knowledge of drawing; tools required and their use;
+ common views needed in mechanical drawing. 2. Perspective versus
+ mechanical drawing in showing plumbing construction. 3. Correct
+ and incorrect methods in plumbing drawing; plan and elevation
+ explained. 4. Floor and cellar plans and elevation; scale
+ drawings; use of triangles. 5. Use of triangles; drawing of
+ fittings, traps, etc. 6. Drawing plumbing elevations and
+ fittings. 7. Instructions in drawing plumbing elevations. 8. The
+ drawing of plumbing fixtures; scale drawings. 9. Drawings of
+ fixtures and fittings. 10. Inking of drawings. 11. Shading of
+ drawings. 12. Shading of drawings. 13. Sectional drawings;
+ drawing of threads. 14. Plumbing elevations from architect's
+ plan. 15. Elevations of separate parts of the plumbing system.
+ 16. Elevations from the architect's plans. 17. Drawings of
+ detail plumbing connections. 18. Architect's plans and plumbing
+ elevations of residence. 19. Plumbing elevations of residence
+ (_continued_); plumbing plans for cottage. 20. Plumbing
+ elevations; roof connections. 21. Plans and plumbing elevations
+ for six-flat building. 22. Drawing of various parts of the
+ plumbing system; use of scales. 23. Use of architect's scales.
+ 24. Special features in the illustrations of country plumbing.
+ 25. Drawing of wrought-iron piping, valves, radiators, coils,
+ etc. 26. Drawing of piping to illustrate heating systems. 150
+ illustrations. Price =$1.50=
+
+
+=Modern Plumbing Illustrated.= By R. M. STARBUCK.
+
+ This book represents the highest standard of plumbing work. It
+ has been adopted and used as a reference book by the United
+ States Government in its sanitary work in Cuba, Porto Rico and
+ the Philippines, and by the principal Boards of Health of the
+ United States and Canada.
+
+ It gives connections, sizes and working data for all fixtures
+ and groups of fixtures. It is helpful to the master plumber in
+ demonstrating to his customers and in figuring work. It gives
+ the mechanic and student quick and easy access to the best
+ modern plumbing practice. Suggestions for estimating plumbing
+ construction are contained in its pages. This book represents,
+ in a word, the latest and best up-to-date practice and should be
+ in the hands of every architect, sanitary engineer and plumber
+ who wishes to keep himself up to the minute on this important
+ feature of construction. Contains following chapters, each
+ illustrated with a full-page plate: Kitchen sink, laundry tubs,
+ vegetable wash sink; lavatories, pantry sinks, contents of
+ marble slabs; bath tub, foot and sitz bath, shower bath; water
+ closets, venting of water closets; low-down water closets, water
+ closets operated by flush valves, water closet range; slop sink,
+ urinals, the bidet; hotel and restaurant sink, grease trap;
+ refrigerators, safe wastes, laundry waste, lines of
+ refrigerators, bar sinks, soda fountain sinks; horse stall,
+ frost-proof water closets; connections for S traps, venting;
+ connections for drum traps; soil-pipe connections; supporting of
+ soil pipe; main trap and fresh-air inlet: floor drains and
+ cellar drains, subsoil drainage; water closets and floor
+ connections; local venting; connections for bath rooms;
+ connections for bath rooms, _continued_; examples of poor
+ practice; roughing work ready for test; testing of plumbing
+ systems; method of continuous venting; continuous venting for
+ two-floor work; continuous venting for two lines of fixtures on
+ three or more floors; continuous venting of water closets;
+ plumbing for cottage house; construction for cellar piping;
+ plumbing for residence, use of special fittings; plumbing for
+ two-flat house: plumbing for apartment building, plumbing for
+ double apartment building; plumbing for office building;
+ plumbing for public toilet rooms; plumbing for public toilet
+ rooms, _continued_; plumbing for bath establishment; plumbing
+ for engine house, factory plumbing, automatic flushing for
+ schools, factories, etc.; use of flushing valves; urinals for
+ public toilet rooms; the Durham system, the destruction of pipes
+ by electrolysis; construction of work without use of lead;
+ automatic sewage lift; automatic sump tank; country plumbing;
+ construction of cesspools; septic tank and automatic sewage
+ siphon; water supply for country house; thawing of water mains
+ and service by electricity; double boilers; hot water supply of
+ large buildings; automatic control of hot-water tank;
+ suggestions for estimating plumbing construction. 407 octavo
+ pages, fully illustrated by 57 full-page engravings. Third,
+ revised and enlarged edition, just issued. Price =$4.00=
+
+
+=Standard Practical Plumbing.= By R. M. STARBUCK.
+
+ A complete practical treatise of 450 pages, covering the subject
+ of Modern Plumbing in all its branches, a large amount of space
+ being devoted to a very complete and practical treatment of the
+ subject of Hot Water Supply and Circulation and Range Boiler
+ Work. Its thirty chapters include about every phase of the
+ subject one can think of, making it an indispensable work to the
+ master plumber, the journeyman plumber, and the apprentice
+ plumber, containing chapters on: the plumber's tools; wiping
+ solder; composition and use; joint wiping; lead work; traps;
+ siphonage of traps; venting; continuous venting; house sewer and
+ sewer connections; house drain; soil piping, roughing; main trap
+ and fresh air inlet; floor, yard, cellar drains, rain leaders,
+ etc.; fixture wastes; water closets; ventilation; improved
+ plumbing connections; residence plumbing; plumbing for hotels,
+ schools, factories, stables, etc.; modern country plumbing;
+ filtration of sewage and water supply; hot and cold supply;
+ range boilers; circulation; circulating pipes; range boiler
+ problems; hot water for large buildings; water lift and its use;
+ multiple connections for hot water boilers; heating of radiation
+ by supply system; theory for the plumber; drawing for the
+ plumber. Fully illustrated by 347 engravings. Price =$3.00=
+
+
+~RECIPE BOOK~
+
+
+=Henley's Twentieth Century Book of Recipes, Formulas and Processes.=
+Edited by GARDNER D. HISCOX.
+
+ The most valuable Techno-chemical Formula Book published,
+ including over 10,000 selected scientific, chemical,
+ technological, and practical recipes and processes.
+
+ This is the most complete Book of Formulas ever published,
+ giving thousands of recipes for the manufacture of valuable
+ articles for everyday use. Hints, Helps, Practical Ideas, and
+ Secret Processes are revealed within its pages. It covers every
+ branch of the useful arts and tells thousands of ways of making
+ money, and is just the book everyone should have at his command.
+
+ Modern in its treatment of every subject that properly falls
+ within its scope, the book may truthfully be said to present the
+ very latest formulas to be found in the arts and industries, and
+ to retain those processes which long experience has proven
+ worthy of a permanent record. To present here even a limited
+ number of the subjects which find a place in this valuable work
+ would be difficult. Suffice to say that in its pages will be
+ found matter of intense interest and immeasurably practical
+ value to the scientific amateur and to him who wishes to obtain
+ a knowledge of the many processes used in the arts, trades and
+ manufacture, a knowledge which will render his pursuits more
+ instructive and remunerative. Serving as a reference book to the
+ small and large manufacturer and supplying intelligent seekers
+ with the information necessary to conduct a process, the work
+ will be found of inestimable worth to the Metallurgist, the
+ Photographer, the Perfumer, the Painter, the Manufacturer of
+ Glues, Pastes, Cements, and Mucilages, the Compounder of Alloys,
+ the Cook, the Physician, the Druggist, the Electrician, the
+ Brewer, the Engineer, the Foundryman, the Machinist, the Potter,
+ the Tanner, the Confectioner, the Chiropodist, the Manicurist,
+ the Manufacturer of Chemical Novelties and Toilet Preparations,
+ the Dyer, the Electroplater, the Enameler, the Hat Maker, the
+ Ink Manufacturer, the Optician, the Farmer, the Dairyman, the
+ Paper Maker, the Wood and Metal Worker, the Chandler and Soap
+ Maker, the Veterinary Surgeon, and the Technologist in general.
+
+ A mine of information, and up-to-date in every respect. A book
+ which will prove of value to EVERYONE, as it covers every branch
+ of the Useful Arts. Every home needs this book; every office,
+ every factory, every store, every public and private
+ enterprise--EVERYWHERE--should have a copy. 800 pages. Price
+ =$3.00=
+
+ WHAT IS SAID OF THIS BOOK:
+
+ "Your Twentieth Century Book of Recipes, Formulas, and Processes
+ duly received. I am glad to have a copy of it, and if I could
+ not replace it, money couldn't buy it. It is the best thing of
+ the sort I ever saw." (Signed) M. E. TRUX, Sparta, Wis.
+
+ "There are few persons who would not be able to find in the book
+ some single formula that would repay several times the cost of
+ the book."--_Merchants' Record and Show Window._
+
+ "I purchased your book, 'Henley's Twentieth Century Book of
+ Recipes, Formulas and Processes,' about a year ago and it is
+ worth its weight in _gold_."--WM. H. MURRAY, Bennington, Vt.
+
+ "ONE OF THE WORLD'S MOST USEFUL BOOKS"
+
+ "Some time ago I got one of your 'Twentieth Century Books of
+ Formulas,' and have made my living from it ever since. I am
+ alone since my husband's death with two small children to care
+ for and am trying so hard to support them. I have customers who
+ take from me Toilet Articles I put up, following directions
+ given in the book, and I have found everyone of them to be
+ fine."--MRS. J. H. MCMAKEN, West Toledo, Ohio.
+
+
+~RUBBER~
+
+
+=Rubber Hand Stamps and the Manipulation of India Rubber.= BY T. O'CONOR
+SLOANE.
+
+ This book gives full details on all points, treating in a
+ concise and simple manner the elements of nearly everything it
+ is necessary to understand for a commencement in any branch of
+ the India Rubber Manufacture. The making of all kinds of Rubber
+ Hand Stamps, Small Articles of India Rubber, U. S. Government
+ Composition, Dating Hand Stamps, the Manipulation of Sheet
+ Rubber, Toy Balloons, India Rubber Solutions, Cements,
+ Blackings, Renovating, Varnish, and Treatment for India Rubber
+ Shoes, etc.; the Hektograph Stamp Inks, and Miscellaneous Notes,
+ with a Short Account of the Discovery, Collection and
+ Manufacture of India Rubber, are set forth in a manner designed
+ to be readily understood, the explanations being plain and
+ simple. Including a chapter on Rubber Tire Making and
+ Vulcanizing; also a chapter on the uses of rubber in Surgery and
+ Dentistry. 3rd Revised and Enlarged Edition. 175 pages.
+ Illustrated =$1.00=
+
+
+~SAWS~
+
+
+=Saw Filing and Management of Saws.= By ROBERT GRIMSHAW.
+
+ A practical hand-book on filing, gumming, swaging, hammering,
+ and the brazing of band saws, the speed, work, and power to run
+ circular saws, etc. A handy book for those who have charge of
+ saws, or for those mechanics who do their own filing, as it
+ deals with the proper shape and pitches of saw teeth of all
+ kinds and gives many useful hints and rules for gumming,
+ setting, and filing, and is a practical aid to those who use
+ saws for any purpose. Complete tables of proper shape, pitch,
+ and saw teeth as well as sizes and number of teeth of various
+ saws are included. 3rd Edition, Revised and Enlarged.
+ Illustrated. Price =$1.00=
+
+
+~STEAM ENGINEERING~
+
+
+=American Stationary Engineering.= By W. E. CRANE.
+
+ This book begins at the boiler room and takes in the whole power
+ plant. A plain talk on every-day work about engines, boilers,
+ and their accessories. It is not intended to be scientific or
+ mathematical. All formulas are in simple form so that any one
+ understanding plain arithmetic can readily understand any of
+ them. The author has made this the most practical book in print;
+ has given the results of his years of experience, and has
+ included about all that has to do with an engine room or a power
+ plant. You are not left to guess at a single point. You are
+ shown clearly what to expect under the various conditions; how
+ to secure the best results; ways of preventing "shut downs" and
+ repairs; in short, all that goes to make up the requirements of
+ a good engineer, capable of taking charge of a plant. It's plain
+ enough for practical men and yet of value to those high in the
+ profession.
+
+ A partial list of contents is: The boiler room, cleaning
+ boilers, firing, feeding; pumps, inspection and repair;
+ chimneys, sizes and cost; piping; mason work; foundations;
+ testing cement; pile driving; engines, slow and high speed;
+ valves; valve setting; Corliss engines, setting valves, single
+ and double eccentric; air pumps and condensers; different types
+ of condensers; water needed; lining up; pounds; pins not square
+ in crosshead or crank; engineers' tools; pistons and piston
+ rings; bearing metal; hardened copper; drip pipes from cylinder
+ jacket; belts, how made, care of; oils; greases; testing
+ lubricants; rules and tables, including steam tables; areas of
+ segments; squares and square roots; cubes and cube root; areas
+ and circumferences of circles. Notes on: Brick work; explosions;
+ pumps; pump valves; heaters, economizers; safety valves; lap,
+ lead, and clearance. Has a complete examination for a license,
+ etc., etc. 3rd Edition. 345 pages, illustrated. Price =$2.00=
+
+
+=Engine Runner's Catechism.= By ROBERT GRIMSHAW.
+
+ A practical treatise for the stationary engineer, telling how to
+ erect, adjust, and run the principal steam engines in use in the
+ United States. Describing the principal features of various
+ special and well-known makes of engines: Temper Cut-off,
+ Shipping and Receiving Foundations, Erecting and Starting, Valve
+ Setting, Care and Use, Emergencies, Erecting and Adjusting
+ Special Engines.
+
+ The questions asked throughout the catechism are plain and to
+ the point, and the answers are given in such simple language as
+ to be readily understood by anyone. All the instructions given
+ are complete and up-to-date; and they are written in a popular
+ style, without any technicalities or mathematical formulae. The
+ work is of a handy size for the pocket, clearly and well
+ printed, nicely bound, and profusely illustrated.
+
+ To young engineers this catechism will be of great value,
+ especially to those who may be preparing to go forward to be
+ examined for certificates of competency; and to engineers
+ generally it will be of no little service, as they will find in
+ this volume more really practical and useful information than is
+ to be found anywhere else within a like compass. 387 pages. 7th
+ Edition. Price =$2.00=
+
+
+=Modern Steam Engineering in Theory and Practice.= By GARDNER D. HISCOX.
+
+ This is a complete and practical work issued for Stationary
+ Engineers and Firemen, dealing with the care and management of
+ boilers, engines, pumps, superheated steam, refrigerating
+ machinery, dynamos, motors, elevators, air compressors, and all
+ other branches with which the modern engineer must be familiar.
+ Nearly 200 questions with their answers on steam and electrical
+ engineering, likely to be asked by the Examining Board, are
+ included.
+
+ Among the chapters are: Historical: steam and its properties;
+ appliances for the generation of steam; types of boilers;
+ chimney and its work; heat economy of the feed water; steam
+ pumps and their work; incrustation and its work; steam above
+ atmospheric pressure; flow of steam from nozzles; superheated
+ steam and its work; adiabatic expansion of steam; indicator and
+ its work; steam engine proportions; slide valve engines and
+ valve motion; Corliss engine and its valve gear; compound engine
+ and its theory; triple and multiple expansion engine; steam
+ turbine; refrigeration; elevators and their management; cost of
+ power; steam engine troubles; electric power and electric
+ plants. 487 pages, 405 engravings. 3rd Edition. Price =$3.00=
+
+
+=Steam Engine Catechism.= By ROBERT GRIMSHAW.
+
+ This unique volume of 413 pages is not only a catechism on the
+ question and answer principle but it contains formulas and
+ worked-out answers for all the Steam problems that appertain to
+ operation and management of the Steam Engine. Illustrations of
+ various valves and valve gear with their principles of operation
+ are given. Thirty-four Tables that are indispensable to every
+ engineer and fireman that wishes to be progressive and is
+ ambitious to become master of his calling are within its pages.
+ It is a most valuable instructor in the service of Steam
+ Engineering. Leading engineers have recommended it as a valuable
+ educator for the beginner as well as a reference book for the
+ engineer. It is thoroughly indexed for every detail. Every
+ essential question on the Steam Engine with its answer is
+ contained in this valuable work. 16th Edition. Price =$2.00=
+
+
+=Steam Engineer's Arithmetic.= By COLVIN-CHENEY.
+
+ A practical pocket-book for the steam engineer. Shows how to
+ work the problems of the engine room and shows "why." Tells how
+ to figure horsepower of engines and boilers; area of boilers;
+ has tables of areas and circumferences; steam tables; has a
+ dictionary of engineering terms. Puts you on to all of the
+ little kinks in figuring whatever there is to figure around a
+ power plant. Tells you about the heat unit; absolute zero;
+ adiabatic expansion; duty of engines; factor of safety; and a
+ thousand and one other things; and everything is plain and
+ simple--not the hardest way to figure, but the easiest. 2nd
+ Edition. Price =50 Cents=
+
+
+=Engine Tests and Boiler Efficiencies.= By J. BUCHETTI.
+
+ This work fully describes and illustrates the method of testing
+ the power of steam engines, turbines and explosive motors. The
+ properties of steam and the evaporative power of fuels.
+ Combustion of fuel and chimney draft; with formulas explained or
+ practically computed. 255 pages, 179 illustrations. Price
+ =$3.00=
+
+
+=Horsepower Chart.=
+
+ Shows the horsepower of any stationary engine without
+ calculation. No matter what the cylinder diameter of stroke, the
+ steam pressure of cut-off, the revolutions, or whether
+ condensing or non-condensing, it's all there. Easy to use.
+ accurate, and saves time and calculations. Especially useful to
+ engineers and designers. Price =50 Cents=
+
+
+~STEAM HEATING AND VENTILATION~
+
+
+=Practical Steam, Hot-Water Heating and Ventilation.= By A. G. KING.
+
+ This book is the standard and latest work published on the
+ subject and has been prepared for the use of all engaged in the
+ business of steam, hot-water heating, and ventilation. It is an
+ original and exhaustive work. Tells how to get heating
+ contracts, how to install heating and ventilating apparatus, the
+ best business methods to be used, with "Tricks of the Trade" for
+ shop use. Rules and data for estimating radiation and cost and
+ such tables and information as make it an indispensable work for
+ everyone interested in steam, hot-water heating, and
+ ventilation. It describes all the principal systems of steam,
+ hot-water, vacuum, vapor, and vacuum-vapor heating, together
+ with the new accelerated systems of hot-water circulation,
+ including chapters on up-to-date methods of ventilation and the
+ fan or blower system of heating and ventilation. Containing
+ chapters on: I. Introduction. II. Heat. III. Evolution of
+ artificial heating apparatus. IV. Boiler surface and settings.
+ V. The chimney flue. VI. Pipe and fittings. VII. Valves, various
+ kinds. VIII. Forms of radiating surfaces. IX. Locating of
+ radiating surfaces. X. Estimating radiation. XI. Steam-heating
+ apparatus XII. Exhaust-steam heating. XIII. Hot-water heating.
+ XIV. Pressure systems of hot-water work. XV. Hot-water
+ appliances. XVI. Greenhouse heating. XVII. Vacuum vapor and
+ vacuum exhaust heating. XVIII. Miscellaneous heating. XIX.
+ Radiator and pipe connections. XX. Ventilation. XXI. Mechanical
+ ventilation and hot-blast heating. XXII. Steam appliances.
+ XXIII. District heating. XXIV. Pipe and boiler covering. XXV.
+ Temperature regulation and heat control. XXVI. Business methods.
+ XXVII. Miscellaneous. XXVIII. Rules, tables, and useful
+ information. 367 pages, 300 detailed engravings. 2nd
+ Edition--Revised. Price =$3.00=
+
+
+=Five Hundred Plain Answers to Direct Questions on Steam, Hot-Water,
+Vapor and Vacuum Heating Practice.= By ALFRED G. KING.
+
+ This work, just off the press, is arranged in question and
+ answer form; it is intended as a guide and text-book for the
+ younger, inexperienced fitter and as a reference book for all
+ fitters. This book tells "how" and also tells "why". No work of
+ its kind has ever been published. It answers all the questions
+ regarding each method or system that would be asked by the steam
+ fitter or heating contractor, and may be used as a text or
+ reference book, and for examination questions by Trade Schools
+ or Steam Fitters' Associations. Rules, data, tables and
+ descriptive methods are given, together with much other detailed
+ information of daily practical use to those engaged in or
+ interested in the various methods of heating. Valuable to those
+ preparing for examinations. Answers every question asked
+ relating to modern Steam, Hot-Water, Vapor and Vacuum Heating.
+ Among the contents are: The Theory and Laws of Heat. Methods of
+ Heating. Chimneys and Flues. Boilers for Heating. Boiler
+ Trimmings and Settings. Radiation. Steam Heating. Boiler,
+ Radiator and Pipe Connections for Steam Heating. Hot Water
+ Heating. The Two-Pipe Gravity System of Hot Water Heating. The
+ Circuit System of Hot Water Heating. The Overhead System of Hot
+ Water Heating. Boiler, Radiator and Pipe Connections for Gravity
+ Systems of Hot Water Heating. Accelerated Hot Water Heating.
+ Expansion Tank Connections. Domestic Hot Water Heating. Valves
+ and Air Valves. Vacuum Vapor and Vacuo-Vapor Heating. Mechanical
+ Systems of Vacuum Heating. Non-Mechanical Vacuum Systems. Vapor
+ Systems. Atmospheric and Modulating Systems. Heating
+ Greenhouses. Information, Rules and Tables. 200 pages, 127
+ illustrations. Octavo. Cloth. Price =$1.50=
+
+
+~STEEL~
+
+
+=Steel: Its Selection, Annealing, Hardening, and Tempering.= By E. R.
+MARKHAM.
+
+ This work was formerly known as "The American Steel Worker," but
+ on the publication of the new, revised edition, the publishers
+ deemed it advisable to change its title to a more suitable one.
+ It is the standard work on Hardening, Tempering, and Annealing
+ Steel of all kinds. This book tells how to select, and how to
+ work, temper, harden, and anneal steel for everything on earth.
+ It doesn't tell how to temper one class of tools and then leave
+ the treatment of another kind of tool to your imagination and
+ judgment, but it gives careful instructions for every detail of
+ every tool, whether it be a tap, a reamer or just a
+ screw-driver. It tells about the tempering of small watch
+ springs, the hardening of cutlery, and the annealing of dies. In
+ fact, there isn't a thing that a steel worker would want to know
+ that isn't included. It is the standard book on selecting,
+ hardening and tempering all grades of steel. Among the chapter
+ headings might be mentioned the following subjects:
+ Introduction; the workman; steel; methods of heating; heating
+ tool steel; forging; annealing; hardening baths; baths for
+ hardening; hardening steel; drawing the temper after hardening;
+ examples of hardening; pack hardening; case hardening; spring
+ tempering; making tools of machine steel; special steels; steel
+ for various tools; causes of trouble; high-speed steels, etc.
+ 400 pages. Very fully illustrated. Fourth edition. Price =$2.50=
+
+
+=Hardening, Tempering, Annealing, and Forging of Steel.= By J. V.
+WOODWORTH.
+
+ A new work treating in a clear, concise manner all modern
+ processes for the heating, annealing, forging, welding,
+ hardening and tempering of steel, making it a book of great
+ practical value to the metal-working mechanic in general, with
+ special directions for the successful hardening and tempering of
+ all steel tools used in the arts, including milling cutters,
+ taps, thread dies, reamers, both solid and shell, hollow mills,
+ punches and dies, and all kinds of sheet-metal working tools,
+ shear blades, saws, fine cutlery, and metal-cutting tools of all
+ description, as well as for all implements of steel both large
+ and small. In this work the simplest and most satisfactory
+ hardening and tempering processes are given.
+
+ The uses to which the leading brands of steel may be adapted are
+ concisely presented, and their treatment for working under
+ different conditions explained, also the special methods for the
+ hardening and tempering of special brands.
+
+ A chapter devoted to the different processes for case-hardening
+ is also included, and special reference made to the adaptation
+ of machinery steel for tools of various kinds, Fourth edition.
+ 288 pages. 201 illustrations. Price =$2.50=
+
+
+~TRACTORS~
+
+
+=The Modern Gas Tractor.= By VICTOR W. PAGE, M.E.
+
+ A complete treatise describing all types and sizes of gasoline,
+ kerosene and oil tractors. Considers design and construction
+ exhaustively, gives complete instructions for care, operation
+ and repair, outlines all practical applications on the road and
+ in the field. The best and latest work on farm tractors and
+ tractor power plants. A work needed by farmers, students,
+ blacksmiths, mechanics, salesmen, implement dealers, designers,
+ and engineers. Second edition, revised and enlarged. 504 pages.
+ Nearly 300 illustrations and folding plates. Price =$2.00=
+
+
+~TURBINES~
+
+
+=Marine Steam Turbines.= By DR. G. BAUER and O. LASCHE. Assisted by E.
+LUDWIG and H. VOGEL.
+
+ Translated from the German and edited by M. G. S. Swallow. The
+ book is essentially practical and discusses turbines in which
+ the full expansion of steam passes through a number of separate
+ turbines arranged for driving two or more shafts, as in the
+ Parsons system, and turbines in which the complete expansion of
+ steam from inlet to exhaust pressure occurs in a turbine on one
+ shaft, as in the case of the Curtis machines. It will enable a
+ designer to carry out all the ordinary calculation necessary for
+ the construction of steam turbines, hence it fills a want which
+ is hardly met by larger and more theoretical works. Numerous
+ tables, curves and diagrams will be found, which explain with
+ remarkable lucidity the reason why turbine blades are designed
+ as they are, the course which steam takes through turbines of
+ various types, the thermodynamics of steam turbine calculation,
+ the influence of vacuum on steam consumption of steam turbines,
+ etc. In a word, the very information which a designer and
+ builder of steam turbines most requires. Large octavo, 214
+ pages. Fully illustrated and containing eighteen tables,
+ including an entropy chart. Price, net =$3.50=
+
+
+~WATCH MAKING~
+
+
+=Watchmaker's Handbook.= By CLAUDIUS SAUNIER.
+
+ No work issued can compare with this book for clearness and
+ completeness. It contains 498 pages and is intended as a
+ workshop companion for those engaged in watch-making and allied
+ mechanical arts. Nearly 250 engravings and fourteen plates are
+ included. This is the standard work on watch-making. Price
+ =$3.00=
+
+
+~WELDING~
+
+
+=Automobile Welding with the Oxy-Acetylene Flame.= By M. KEITH DUNHAM.
+
+ Explains in a simple manner apparatus to be used, its care, and
+ how to construct necessary shop equipment. Proceeds then to the
+ actual welding of all automobile parts, in a manner
+ understandable by every one. _Gives principles never to be
+ forgotten._ Aluminum, cast iron, steel, copper, brass, bronze,
+ and malleable iron are fully treated, as well as a clear
+ explanation of the proper manner to burn the carbon out of the
+ combustion head. This book is of utmost value, since the
+ perplexing problems arising when metal is heated to a melting
+ point are fully explained and the proper methods to overcome
+ them shown. 167 pages, fully illustrated. Price =$1.00=
+
+
+
+
+ Every Practical Man Needs A Magazine Which Will Tell Him How To
+ Make And Do Things
+
+
+ _=Have us enter your subscription to the best mechanical magazine
+ on the market. Only one dollar a year for twelve numbers.
+ Subscribe today to=_
+
+ =Everyday Engineering=
+
+A monthly magazine devoted to practical mechanics for everyday men. Its
+aim is to popularize engineering as a science, teaching the elements of
+applied mechanics and electricity in a straightforward and
+understandable manner. The magazine maintains its own experimental
+laboratory where the devices described in articles submitted to the
+Editor are first tried out and tested before they are published. This
+important innovation places the standard of the published material very
+high, and it insures accuracy and dependability.
+
+The magazine is the only one in this country that specializes in
+practical model building. Articles in past issues have given
+comprehensive designs for many model boats, including submarines and
+chasers, model steam and gasoline engines, electric motors and
+generators, etc., etc. This feature is a permanent one in this magazine.
+
+Another popular department is that devoted to automobiles and airplanes.
+Care, maintenance, and operation receive full and authoritative
+treatment. Every article is written from the practical, everyday man,
+standpoint rather than from that of the professional.
+
+The magazine entertains while it instructs. It is a journal of
+practical, dependable information given in such a style that it may be
+readily assimilated and applied by the man with little or no technical
+training. The aim is to place before the man who leans toward practical
+mechanics, a series of concise, crisp, readable talks on what is going
+on and _how it is done_. These articles are profusely illustrated with
+clear, snappy photographs, specially posed to illustrate the subject in
+the magazine's own studio by its own staff of technically-trained
+illustrators and editors.
+
+=The subscription price of the magazine is one dollar per year of twelve
+numbers. Sample copy sent on receipt of ten cents.=
+
+Enter your subscription to this practical magazine with your bookseller.
+
+
+=The Norman W. Henley Publishing Co.,=
+
+=2 West 45th Street, New York=
+
+
+
+
+ +-----------------------------------------------------------------+
+ | TRANSCRIBER'S NOTES |
+ | |
+ | General remarks: |
+ | There are some differences in wording between the Table of |
+ | Contents, the lists of sections per chapter, and the actual |
+ | section titles. Their meaning is clear, and they have been |
+ | left as they were in the original work. |
+ | Page 56, table: Fig. 8 in the first column does not refer to |
+ | Fig. 8 in this work. |
+ | The original work does not have a Figure 89. |
+ | Page 303, table: it is uncertain what "free with kerosene" |
+ | means, there may be a word omitted. |
+ | Page 544, entirely censored. It is not clear what this page |
+ | originally contained (possibly a table), since text and |
+ | numbering of illustrations are uninterrupted. The text |
+ | "CENSORED" has been moved to after the first paragraph of the |
+ | section on Mercedes Engines. |
+ | The List of Illustrations does not occur in the original work.|
+ | |
+ | Changes made: |
+ | The text of the original work (including inconsistencies in |
+ | accents, spelling, hyphenation and lay-out, and differences |
+ | between the main text, illustrations and advertisements) has |
+ | been followed, except when listed below. Only some minor |
+ | obvious typographical errors have been corrected silently. |
+ | Where the author used x for multiplication, this has been |
+ | replaced by x in the body of the text (not in the |
+ | advertisements or illustrations). |
+ | The illustrations have been moved so as not to disrupt the |
+ | flow of the text. |
+ | Engine and aircraft types are not always named consistently in|
+ | the original; Curtiss engine O X 2, OX-2 and 0X2 have all |
+ | been changed to OX-2, Curtiss aircraft JN4 and JN-4 to JN-4. |
+ | Multi-page tables: repeated headings have been removed, and |
+ | the tables treated as one consecutive table. |
+ | Page 22: "The product of" has been moved into the first |
+ | formula. |
+ | Page 25: "When B x r = M" changed to "When P x r = M". |
+ | Page 74: ".225 / 775 = .2905" changed to ".225 / .775 = |
+ | .2905". |
+ | Page 137 (caption): "Bavary" changed to "Baverey" as |
+ | elsewhere. |
+ | Page 172: "evidently" changed to "evident". |
+ | Page 214: "drop to O" changed to "drop to 0". |
+ | Page 248: "actual from a common" changed to "actuated from a |
+ | common". |
+ | Page 256: "values" changed to "valves". |
+ | Page 280: "Fig. 6" changed to "Fig. 112". |
+ | Page 306: "Fig. 127, B" changed to "Fig. 127, C" (2nd |
+ | reference). |
+ | Page 324: "Rhone" changed to "Le Rhone" as elsewhere. |
+ | Page 334: "Check values" changed to "Check valves". |
+ | Page 364: "LeRhone" changed to "Le Rhone" as elsewhere. |
+ | Page 390: "Fig. 62, D" changed to "Fig. 168, B". |
+ | Page 408: "Stilson" changed to "Stillson" as elsewhere. |
+ | Page 490: "both valves" changed to "both halves". |
+ | Page 514: "standard ratio is 5.3" changed to "standard ratio |
+ | is 5:3". |
+ | Page 529: "gallons per minute 1,400 R. P. M." changed to |
+ | "gallons per minute at 1,400 R. P. M." |
+ | Page 546: "Hispano Suiza" changed to "Hispano-Suiza" as |
+ | elsewhere. |
+ | Page 556: "Diameter of crank-shaft, 56 mm." changed to |
+ | "Diameter of crank-shaft, 55 mm." |
+ | Page 7 (advertisements): "Hazlehurst Field" changed to |
+ | "Hazelhurst Field". |
+ | Page 21 (advertisements): "Rhose Island Compound" changed to |
+ | "Rhode Island Compound". |
+ | Index: "Shebler" changed to "Schebler", "camshaft" to |
+ | "cam-shaft", "wristpin" to "wrist-pin", etc. (all as in text).|
+ +-----------------------------------------------------------------+
+
+
+
+***END OF THE PROJECT GUTENBERG EBOOK AVIATION ENGINES***
+
+
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