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diff --git a/old/flymc10.txt b/old/flymc10.txt new file mode 100644 index 0000000..f7cd45e --- /dev/null +++ b/old/flymc10.txt @@ -0,0 +1,7363 @@ +Project Gutenberg Etext; Flying Machines: Construction/Operation + + +Copyright laws are changing all over the world, be sure to check +the copyright laws for your country before posting these files!! + +Please take a look at the important information in this header. +We encourage you to keep this file on your own disk, keeping an +electronic path open for the next readers. Do not remove this. + + +**Welcome To The World of Free Plain Vanilla Electronic Texts** + +**Etexts Readable By Both Humans and By Computers, Since 1971** + +*These Etexts Prepared By Hundreds of Volunteers and Donations* + +Information on contacting Project Gutenberg to get Etexts, and +further information is included below. We need your donations. + + +Flying Machines: Construction and Operation + +W.J. Jackman and Thos. H. 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Russell + + + +FLYING MACHINES: CONSTRUCTION and OPERATION + + + +A Practical Book Which Shows, in Illustrations, +Working Plans and Text, How to Build and Navigate the +Modern Airship. + +By +W.J. Jackman, M.E., +Author of "A B C of the Motorcycle," +"Facts for Motorists," etc. etc. + +AND + +THOS. H. RUSSELL, A.M., M.E., +Charter Member of the Aero Club of Illinois, Author of +"History of the Automobile," "Motor Boats: Construction +and Operation," etc. etc. + +WITH INTRODUCTORY CHAPTER BY +OCTAVE CHANUTE, C.E., +President Aero Club of Illinois + +1912 + + + +PREFACE. + +This book is written for the guidance of the novice in +aviation--the man who seeks practical information as to +the theory, construction and operation of the modern +flying machine. With this object in view the wording +is intentionally plain and non-technical. It contains some +propositions which, so far as satisfying the experts is +concerned, might doubtless be better stated in technical +terms, but this would defeat the main purpose of its preparation. +Consequently, while fully aware of its shortcomings +in this respect, the authors have no apologies to make. + +In the stating of a technical proposition so it may be +clearly understood by people not versed in technical matters +it becomes absolutely necessary to use language +much different from that which an expert would employ, +and this has been done in this volume. + +No man of ordinary intelligence can read this book +without obtaining a clear, comprehensive knowledge of +flying machine construction and operation. He will +learn, not only how to build, equip, and manipulate an +aeroplane in actual flight, but will also gain a thorough +understanding of the principle upon which the suspension +in the air of an object much heavier than the air is made +possible. + +This latter feature should make the book of interest +even to those who have no intention of constructing or +operating a flying machine. It will enable them to better +understand and appreciate the performances of the +daring men like the Wright brothers, Curtiss, Bleriot, +Farman, Paulhan, Latham, and others, whose bold experiments +have made aviation an actuality. + +For those who wish to engage in the fascinating pastime +of construction and operation it is intended as a +reliable, practical guide. + +It may be well to explain that the sub-headings in the +articles by Mr. Chanute were inserted by the authors +without his knowledge. The purpose of this was merely +to preserve uniformity in the typography of the book. +This explanation is made in justice to Mr. Chanute. + THE AUTHORS. + + + +IN MEMORIAM. + +Octave Chanute, "the father of the modern flying machine," +died at his home in Chicago on November 23, 1910, +at the age of 72 years. His last work in the interest of +aviation was to furnish the introductory chapter to the first +edition of this volume, and to render valuable assistance +in the handling of the various subjects. He even made the +trip from his home to the office of the publishers one +inclement day last spring, to look over the proofs of the +book and, at his suggestion, several important changes were +made. All this was "a labor of love" on Mr. Chanute's +part. He gave of his time and talents freely because he +was enthusiastic in the cause of aviation, and because he +knew the authors of this book and desired to give them +material aid in the preparation of the work--a favor that +was most sincerely appreciated. + + +The authors desire to make acknowledgment of many courtesies +in the way of valuable advice, information, etc., extended by Mr. +Octave Chanute, C. E., Mr. E. L. Jones, Editor of Aeronautics, +and the publishers of, the New England Automobile Journal and +Fly. + + + +CONTENTS + +Chapter + +I. Evolution of the Two-Surface Flying Machine + Introductory Chapter by Octave Chanute, C. E. +II. Theory Development and Use + Origin of the Aeroplane--Developments by Chanute + and the Wrights--Practical Uses and Limits. +III. Mechanical Bird Action + What the Motor Does--Puzzle in Bird Soaring. +IV. Various Forms of Flying Machines + Helicopters, Ornithopters and Aeroplanes-- + Monoplanes, Biplanes and Triplanes. +V. Constructing a Gliding Machine + Plans and Materials Required--Estimate of Cost-- + Sizes and Preparation of Various Parts--Putting the + Parts Together +VI. Learning to Fly + How to Use the Glider--Effect of Body Movements + --Rules for Beginners--Safest Place to Glide. +VII. Putting On the Rudder + Its Construction, Application and Use. +VIII. The Real Flying Machine + Surface Area Required--Proper Size of Frame and + Auxiliaries--Installation of Motor--Cost of + Constructing Machine. +IX. Selection of the Motor + Essential Features--Multiplicity of Cylinders--Power + Required--Kind and Action of Propellers--Placing + of the Motor +X. Proper Dimensions of Machines + Figuring Out the Details--How to Estimate Load + Capacity--Distribution of the Weight--Measurements + of Leading Machines. +XI. Plane and Rudder Control + Various Methods in Use--Wheels and Hand and + Foot Levers +XII. How to Use the Machine + Rules of Leading Aviators--Rising from the Ground + --Reasonable Altitude--Preserving Equilibrium-- + Learning to Steer. +XIII. Peculiarities of Aeroplane Power + Pressure of the Wind--How to Determine Upon + Power--Why Speed Is Required--Bird find Flying + Machine Areas. +XIV. About Wind Currents, Etc. + Uncertainty of Direct Force--Trouble With Gusty + Currents--Why Bird Action Is Imitated. +XV. The Element of Danger + Risk Small Under Proper Conditions--Two Fields + of Safety--Lessons in Recent Accidents. +XVI. Radical Changes Being Made + Results of Recent Experiments--New Dimensions + --Increased Speed--The One Governing Rule. +XVII. Some of the New Designs + ù Automatic Control of Plane Stability--Inventor + Herring's Devices--Novel Ideas of Students. +XVIII. Demand for Flying Machines + Wonderful Results in a Year--Factories Over- + crowded with Orders. +XIX. Law of the Airship + Rights of Property Owners--Some Legal + Peculiarities--Danger of Trespass. +XX. Soaring Flight +XXI. Flying Machines vs. Balloons +XXII. Problems of Aerial Fligh +XXIII. Amateurs May Use Wright Patents +XXIV. Hints on Propeller Construction +XXV. New Motors and Devices +XXVI. Monoplanes, Triplanes, Multiplanes +XXVII. Records of Various Kinds + + + + +FLYING MACHINES: CONSTRUCTION and OPERATION + + + +CHAPTER I. + +EVOLUTION OF TWO-SURFACE FLYING MACHINE. + +By Octave Chanute. + + +I am asked to set forth the development of the "two- +surface" type of flying machine which is now used with +modifications by Wright Brothers, Farman, [1]Delagrange, +Herring and others. + + +[1] Now dead. + + +This type originated with Mr. F. H. Wenham, who +patented it in England in 1866 (No. 1571), taking out +provisional papers only. In the abridgment of British +patent Aeronautical Specifications (1893) it is described +as follows: + +"Two or more aeroplanes are arranged one above the +other, and support a framework or car containing the +motive power. The aeroplanes are made of silk or canvas +stretched on a frame by wooden rods or steel ribs. +When manual power is employed the body is placed +horizontally, and oars or propellers are actuated by the +arms or legs. + +"A start may be obtained by lowering the legs and +running down hill or the machine may be started from +a moving carriage. One or more screw propellers may +be applied for propelling when steam power is employed. + +On June 27, 1866, Mr. Wenham read before the +"Aeronautical Society of Great Britain," then recently +organized, the ablest paper ever presented to that society, and +thereby breathed into it a spirit which has continued to +this day. In this paper he described his observations of +birds, discussed the laws governing flight as to the +surfaces and power required both with wings and screws, +and he then gave an account of his own experiments with +models and with aeroplanes of sufficient size to carry +the weight of a man. + +Second Wenham Aeroplane. + +His second aeroplane was sixteen feet from tip to tip. +A trussed spar at the bottom carried six superposed +bands of thin holland fabric fifteen inches wide, connected +with vertical webs of holland two feet apart, thus +virtually giving a length of wing of ninety-six feet and +one hundred and twenty square feet of supporting surface. +The man was placed horizontally on a base board +beneath the spar. This apparatus when tried in the wind +was found to be unmanageable by reason of the fluttering +motions of the fabric, which was insufficiently stiffened +with crinoline steel, but Mr. Wenham pointed out that +this in no way invalidated the principle of the apparatus, +which was to obtain large supporting surfaces without +increasing unduly the leverage and consequent weight +of spar required, by simply superposing the surfaces. + +This principle is entirely sound and it is surprising that +it is, to this day, not realized by those aviators who are +hankering for monoplanes. + +Experiments by Stringfellow. + +The next man to test an apparatus with superposed +surfaces was Mr. Stringfellow, who, becoming much impressed +with Mr. Wenham's proposal, produced a largish +model at the exhibition of the Aeronautical Society in +1868. It consisted of three superposed surfaces aggregating 28 +square feet and a tail of 8 square feet more. +The weight was under 12 pounds and it was driven by a +central propeller actuated by a steam engine overestimated +at one-third of a horsepower. It ran suspended +to a wire on its trials but failed of free flight, in +consequence of defective equilibrium. This apparatus has +since been rebuilt and is now in the National Museum +of the Smithsonian Institution at Washington. +Linfield's Unsuccessful Efforts. + +In 1878 Mr. Linfield tested an apparatus in England +consisting of a cigar-shaped car, to which was attached +on each side frames five feet square, containing each +twenty-five superposed planes of stretched and varnished +linen eighteen inches wide, and only two inches apart, +thus reminding one of a Spanish donkey with panniers. +The whole weighed two hundred and forty pounds. This +was tested by being mounted on a flat car behind a +locomotive going 40 miles an hour. When towed by a line +fifteen feet long the apparatus rose only a little from the +car and exhibited such unstable equilibrium that the +experiment was not renewed. The lift was only about one- +third of what it would have been had the planes been +properly spaced, say their full width apart, instead of +one-ninth as erroneously devised. + +Renard's "Dirigible Parachute." + +In 1889 Commandant Renard, the eminent superintendent +of the French Aeronautical Department, exhibited +at the Paris Exposition of that year, an apparatus +experimented with some years before, which he termed +a "dirigible parachute." It consisted of an oviform body +to which were pivoted two upright slats carrying above +the body nine long superposed flat blades spaced about +one-third of their width apart. When this apparatus +was properly set at an angle to the longitudinal axis of +the body and dropped from a balloon, it travelled back +against the wind for a considerable distance before +alighting. The course could be varied by a rudder. No +practical application seems to have been made of this +device by the French War Department, but Mr. J. P. +Holland, the inventor of the submarine boat which bears +his name, proposed in 1893 an arrangement of pivoted +framework attached to the body of a flying machine +which combines the principle of Commandant Renard +with the curved blades experimented with by Mr. Phillips, +now to be noticed, with the addition of lifting screws +inserted among the blades. + +Phillips Fails on Stability Problem. + +In 1893 Mr. Horatio Phillips, of England, after some +very interesting experiments with various wing sections, +from which he deduced conclusions as to the shape of +maximum lift, tested an apparatus resembling a Venetian +blind which consisted of fifty wooden slats of +peculiar shape, 22 feet long, one and a half inches wide, +and two inches apart, set in ten vertical upright boards. +All this was carried upon a body provided with three +wheels. It weighed 420 pounds and was driven at 40 +miles an hour on a wooden sidewalk by a steam engine +of nine horsepower which actuated a two-bladed screw. +The lift was satisfactory, being perhaps 70 pounds per +horsepower, but the equilibrium was quite bad and the +experiments were discontinued. They were taken up +again in 1904 with a similar apparatus large enough to +carry a passenger, but the longitudinal equilibrium was +found to be defective. Then in 1907 a new machine was +tested, in which four sets of frames, carrying similar sets +of slat "sustainers" were inserted, and with this +arrangement the longitudinal stability was found to be very +satisfactory. The whole apparatus, with the operator, +weighed 650 pounds. It flew about 200 yards when +driven by a motor of 20 to 22 h.p. at 30 miles an hour, +thus exhibiting a lift of about 32 pounds per h.p., while +it will be remembered that the aeroplane of Wright +Brothers exhibits a lifting capacity of 50 pounds to +the h.p. + +Hargrave's Kite Experiments. + +After experimenting with very many models and +building no less than eighteen monoplane flying model +machines, actuated by rubber, by compressed air and by +steam, Mr. Lawrence Hargrave, of Sydney, New South +Wales, invented the cellular kite which bears his name +and made it known in a paper contributed to the Chicago +Conference on Aerial Navigation in 1893, describing +several varieties. The modern construction is well +known, and consists of two cells, each of superposed surfaces +with vertical side fins, placed one behind the other +and connected by a rod or frame. This flies with great +steadiness without a tail. Mr. Hargrave's idea was to +use a team of these kites, below which he proposed to +suspend a motor and propeller from which a line would +be carried to an anchor in the ground. Then by actuating +the propeller the whole apparatus would move +forward, pick up the anchor and fly away. He said: +"The next step is clear enough, namely, that a flying +machine with acres of surface can be safely got under +way or anchored and hauled to the ground by means of +the string of kites." + +The first tentative experiments did not result well and +emphasized the necessity for a light motor, so that Mr. +Hargrave has since been engaged in developing one, not +having convenient access to those which have been produced +by the automobile designers and builders. + +Experiments With Glider Model. + +And here a curious reminiscence may be indulged in. +In 1888 the present writer experimented with a two-cell +gliding model, precisely similar to a Hargrave kite, as +will be confirmed by Mr. Herring. It was frequently +tested by launching from the top of a three-story house +and glided downward very steadily in all sorts of breezes, +but the angle of descent was much steeper than that of +birds, and the weight sustained per square foot was less +than with single cells, in consequence of the lesser support +afforded by the rear cell, which operated upon air +already set in motion downward by the front cell, so +nothing more was done with it, for it never occurred to +the writer to try it as a kite and he thus missed the +distinction which attaches to Hargrave's name. + +Sir Hiram Maxim also introduced fore and aft superposed +surfaces in his wondrous flying machine of 1893, +but he relied chiefly for the lift upon his main large surface +and this necessitated so many guys, to prevent distortion, +as greatly to increase the head resistance and +this, together with the unstable equilibrium, made it +evident that the design of the machine would have to +be changed. + +How Lilienthal Was Killed. + +In 1895, Otto Lilienthal, the father of modern aviation, +the man to whose method of experimenting almost all +present successes are due, after making something like +two thousand glides with monoplanes, added a superposed +surface to his apparatus and found the control of +it much improved. The two surfaces were kept apart +by two struts or vertical posts with a few guy wires, but +the connecting joints were weak and there was nothing +like trussing. This eventually cost his most useful life. +Two weeks before that distressing loss to science, Herr +Wilhelm Kress, the distinguished and veteran aviator +of Vienna, witnessed a number of glides by Lilienthal +with his double-decked apparatus. He noticed that it +was much wracked and wobbly and wrote to me after +the accident: "The connection of the wings and the +steering arrangement were very bad and unreliable. I +warned Herr Lilienthal very seriously. He promised +me that he would soon put it in order, but I fear that he +did not attend to it immediately." + +In point of fact, Lilienthal had built a new machine, +upon a different principle, from which he expected great +results, and intended to make but very few more flights +with the old apparatus. He unwisely made one too +many and, like Pilcher, was the victim of a distorted +apparatus. Probably one of the joints of the struts +gave way, the upper surface blew back and Lilienthal, +who was well forward on the lower surface, was pitched +headlong to destruction. + +Experiments by the Writer. + +In 1896, assisted by Mr. Herring and Mr. Avery, I +experimented with several full sized gliding machines, +carrying a man. The first was a Lilienthal monoplane +which was deemed so cranky that it was discarded after +making about one hundred glides, six weeks before +Lilienthal's accident. The second was known as the +multiple winged machine and finally developed into five +pairs of pivoted wings, trussed together at the front and +one pair in the rear. It glided at angles of descent of +10 or 11 degrees or of one in five, and this was deemed +too steep. Then Mr. Herring and myself made computations +to analyze the resistances. We attributed much +of them to the five front spars of the wings and on a +sheet of cross-barred paper I at once drew the design for +a new three-decked machine to be built by Mr. Herring. + +Being a builder of bridges, I trussed these surfaces +together, in order to obtain strength and stiffness. When +tested in gliding flight the lower surface was found too +near the ground. It was taken off and the remaining +apparatus now consisted of two surfaces connected together +by a girder composed of vertical posts and diagonal +ties, specifically known as a "Pratt truss." Then +Mr. Herring and Mr. Avery together devised and put +on an elastic attachment to the tail. This machine +proved a success, it being safe and manageable. Over +700 glides were made with it at angles of descent of 8 +to 10 degrees, or one in six to one in seven. + +First Proposed by Wenham. + +The elastic tail attachment and the trussing of the +connecting frame of the superposed wings were the only +novelties in this machine, for the superposing of the +surfaces had first been proposed by Wenham, but in +accordance with the popular perception, which bestows +all the credit upon the man who adds the last touch +making for success to the labors of his predecessors, the +machine has since been known by many persons as the +"Chanute type" of gliders, much to my personal gratification. + +It has since been improved in many ways. Wright +Brothers, disregarding the fashion which prevails among +birds, have placed the tail in front of their apparatus and +called it a front rudder, besides placing the operator in +horizontal position instead of upright, as I did; and also +providing a method of warping the wings to preserve +equilibrium. Farman and Delagrange, under the very +able guidance and constructive work of Voisin brothers, +then substituted many details, including a box tail for +the dart-like tail which I used. This may have increased +the resistance, but it adds to the steadiness. Now the +tendency in France seems to be to go back to the monoplane. + +Monoplane Idea Wrong. + +The advocates of the single supporting surface are +probably mistaken. It is true that a single surface +shows a greater lift per square foot than superposed +surfaces for a given speed, but the increased weight due +to leverage more than counterbalances this advantage by +requiring heavy spars and some guys. I believe that +the future aeroplane dynamic flier will consist of superposed +surfaces, and, now that it has been found that by +imbedding suitably shaped spars in the cloth the head +resistance may be much diminished, I see few objections +to superposing three, four or even five surfaces properly +trussed, and thus obtaining a compact, handy, manageable +and comparatively light apparatus.[2] + + +[2] Aeronautics. + + + +CHAPTER II. + +THEORY, DEVELOPMENT, AND USE. + + +While every craft that navigates the air is an airship, +all airships are not flying machines. The balloon, +for instance, is an airship, but it is not what is known +among aviators as a flying machine. This latter term +is properly used only in referring to heavier-than-air +machines which have no gas-bag lifting devices, and are made to +really fly by the application of engine propulsion. + +Mechanical Birds. + +All successful flying machines--and there are a number +of them--are based on bird action. The various +designers have studied bird flight and soaring, mastered +its technique as devised by Nature, and the modern flying +machine is the result. On an exaggerated, enlarged +scale the machines which are now navigating the air +are nothing more nor less than mechanical birds. + +Origin of the Aeroplane. + +Octave Chanute, of Chicago, may well be called "the +developer of the flying machine." Leaving balloons and +various forms of gas-bags out of consideration, other +experimenters, notably Langley and Lilienthal, antedated +him in attempting the navigation of the air on +aeroplanes, or flying machines, but none of them were +wholly successful, and it remained for Chanute to demonstrate +the practicability of what was then called the +gliding machine. This term was adopted because the +apparatus was, as the name implies, simply a gliding +machine, being without motor propulsion, and intended +solely to solve the problem of the best form of +construction. The biplane, used by Chanute in 1896, is +still the basis of most successful flying machines, the +only radical difference being that motors, rudders, etc., +have been added. + +Character of Chanute's Experiments. + +It was the privilege of the author of this book to be +Mr. Chanute's guest at Millers, Indiana, in 1896, when, +in collaboration with Messrs. Herring and Avery, he was +conducting the series of experiments which have since +made possible the construction of the modern flying +machine which such successful aviators as the Wright +brothers and others are now using. It was a wild +country, much frequented by eagles, hawks, and similar +birds. The enthusiastic trio, Chanute, Herring and +Avery, would watch for hours the evolutions of some +big bird in the air, agreeing in the end on the verdict, +"When we master the principle of that bird's soaring +without wing action, we will have come close to solving +the problem of the flying machine." + +Aeroplanes of various forms were constructed by Mr. +Chanute with the assistance of Messrs. Herring and +Avery until, at the time of the writer's visit, they had +settled upon the biplane, or two-surface machine. Mr. +Herring later equipped this with a rudder, and made +other additions, but the general idea is still the basis of +the Wright, Curtiss, and other machines in which, by +the aid of gasolene motors, long flights have been made. + +Developments by the Wrights. + +In 1900 the Wright brothers, William and Orville, who were then +in the bicycle business in Dayton, Ohio, +became interested in Chanute's experiments and +communicated with him. The result was that the Wrights +took up Chanute's ideas and developed them further, +making many additions of their own, one of which was +the placing of a rudder in front, and the location of the +operator horizontally on the machine, thus diminishing +by four-fifths the wind resistance of the man's body. +For three years the Wrights experimented with the +glider before venturing to add a motor, which was not +done until they had thoroughly mastered the control of +their movements in the air. + +Limits of the Flying Machine. + +In the opinion of competent experts it is idle to look +for a commercial future for the flying machine. There +is, and always will be, a limit to its carrying capacity +which will prohibit its employment for passenger or +freight purposes in a wholesale or general way. There +are some, of course, who will argue that because a +machine will carry two people another may be constructed +that will carry a dozen, but those who make +this contention do not understand the theory of weight +sustentation in the air; or that the greater the load the +greater must be the lifting power (motors and plane +surface), and that there is a limit to these--as will be +explained later on--beyond which the aviator cannot go. + +Some Practical Uses. + +At the same time there are fields in which the flying +machine may be used to great advantage. These are: + +Sports--Flying machine races or flights will always +be popular by reason of the element of danger. It is +a strange, but nevertheless a true proposition, that it is +this element which adds zest to all sporting events. + +Scientific--For exploration of otherwise inaccessible +regions such as deserts, mountain tops, etc. + +Reconnoitering--In time of war flying machines may +be used to advantage to spy out an enemy's encampment, +ascertain its defenses, etc. + + + +CHAPTER III. + +MECHANICAL BIRD ACTION + +In order to understand the theory of the modern flying +machine one must also understand bird action and wind +action. In this connection the following simple experiment +will be of interest: + +Take a circular-shaped bit of cardboard, like the lid of +a hat box, and remove the bent-over portion so as to +have a perfectly flat surface with a clean, sharp edge. +Holding the cardboard at arm's length, withdraw your +hand, leaving the cardboard without support. What is +the result? The cardboard, being heavier than air, and +having nothing to sustain it, will fall to the ground. +Pick it up and throw it, with considerable force, against +the wind edgewise. What happens? Instead of falling +to the ground, the cardboard sails along on the wind, +remaining afloat so long as it is in motion. It seeks +the ground, by gravity, only as the motion ceases, and +then by easy stages, instead of dropping abruptly as in +the first instance. + +Here we have a homely, but accurate illustration of +the action of the flying machine. The motor does for +the latter what the force of your arm does for the cardboard-- +imparts a motion which keeps it afloat. The +only real difference is that the motion given by the +motor is continuous and much more powerful than that +given by your arm. The action of the latter is limited +and the end of its propulsive force is reached within a +second or two after it is exerted, while the action of the +motor is prolonged. + +Another Simple Illustration. + +Another simple means of illustrating the principle of +flying machine operation, so far as sustentation and the +elevation and depression of the planes is concerned, is +explained in the accompanying diagram. + +A is a piece of cardboard about 2 by 3 inches in size. +B is a piece of paper of the same size pasted to one edge +of A. If you bend the paper to a curve, with convex +side up and blow across it as shown in Figure C, the +paper will rise instead of being depressed. The dotted +lines show that the air is passing over the top of the +curved paper and yet, no matter how hard you may +blow, the effect will be to elevate the paper, despite the +fact that the air is passing over, instead of under the +curved surface. + +In Figure D we have an opposite effect. Here the +paper is in a curve exactly the reverse of that shown in +Figure C, bringing the concave side up. Now if you +will again blow across the surface of the card the action +of the paper will be downward--it will be impossible to +make it rise. The harder you blow the greater will be +the downward movement. + +Principle In General Use. + +This principle is taken advantage of in the construction +of all successful flying machines. Makers of monoplanes +and biplanes alike adhere to curved bodies, with +the concave surface facing downward. Straight planes +were tried for a time, but found greatly lacking in the +power of sustentation. By curving the planes, and placing +the concave surface downward, a sort of inverted bowl +is formed in which the air gathers and exerts a buoyant +effect. Just what the ratio of the curve should be is a +matter of contention. In some instances one inch to the +foot is found to be satisfactory; in others this is doubled, +and there are a few cases in which a curve of as much as +3 inches to the foot has been used. + +Right here it might be well to explain that the word +"plane" applied to flying machines of modern construction +is in reality a misnomer. Plane indicates a flat, +level surface. As most successful flying machines have +curved supporting surfaces it is clearly wrong to speak +of "planes," or "aeroplanes." Usage, however, has made +the terms convenient and, as they are generally accepted +and understood by the public, they are used in like manner +in this volume. + +Getting Under Headway. + +A bird, on first rising from the ground, or beginning +its flight from a tree, will flap its wings to get under +headway. Here again we have another illustration of +the manner in which a flying machine gets under headway-- +the motor imparts the force necessary to put the +machine into the air, but right here the similarity ceases. +If the machine is to be kept afloat the motor must be +kept moving. A flying machine will not sustain itself; +it will not remain suspended in the air unless it is +under headway. This is because it is heavier than air, +and gravity draws it to the ground. + +Puzzle in Bird Soaring. + +But a bird, which is also heavier than air, will remain +suspended, in a calm, will even soar and move in a +circle, without apparent movement of its wings. This +is explained on the theory that there are generally vertical +columns of air in circulation strong enough to sustain +a bird, but much too weak to exert any lifting power +on a flying machine, It is easy to understand how a +bird can remain suspended when the wind is in action, +but its suspension in a seeming dead calm was a puzzle +to scientists until Mr. Chanute advanced the proposition +of vertical columns of air. + +Modeled Closely After Birds. + +So far as possible, builders of flying machines have +taken what may be called "the architecture" of birds as +a model. This is readily noticeable in the form of +construction. When a bird is in motion its wings (except +when flapping) are extended in a straight line at right +angles to its body. This brings a sharp, thin edge +against the air, offering the least possible surface for +resistance, while at the same time a broad surface for +support is afforded by the flat, under side of the wings. +Identically the same thing is done in the construction of +the flying machine. + +Note, for instance, the marked similarity in form as +shown in the illustration in Chapter II. Here A is the +bird, and B the general outline of the machine. The +thin edge of the plane in the latter is almost a duplicate +of that formed by the outstretched wings of the bird, +while the rudder plane in the rear serves the same purpose +as the bird's tail. + + + +CHAPTER IV. + +VARIOUS FORMS OF FLYING MACHINES. + +There are three distinct and radically different forms +of flying machines. These are: + +Aeroplanes, helicopters and ornithopers. + +Of these the aeroplane takes precedence and is used +almost exclusively by successful aviators, the helicopters +and ornithopers having been tried and found lacking in +some vital features, while at the same time in some +respects the helicopter has advantages not found in the +aeroplane. + +What the Helicopter Is. + +The helicopter gets its name from being fitted with +vertical propellers or helices (see illustration) by the +action of which the machine is raised directly from the +ground into the air. This does away with the necessity +for getting the machine under a gliding headway before +it floats, as is the case with the aeroplane, and consequently +the helicopter can be handled in a much smaller +space than is required for an aeroplane. This, in many +instances, is an important advantage, but it is the only +one the helicopter possesses, and is more than overcome +by its drawbacks. The most serious of these is that the +helicopter is deficient in sustaining capacity, and requires +too much motive power. + +Form of the Ornithopter. + +The ornithopter has hinged planes which work like +the wings of a bird. At first thought this would seem +to be the correct principle, and most of the early experimenters +conducted their operations on this line. It +is now generally understood, however, that the bird in +soaring is in reality an aeroplane, its extended wings +serving to sustain, as well as propel, the body. At any +rate the ornithoper has not been successful in aviation, +and has been interesting mainly as an ingenious toy. +Attempts to construct it on a scale that would permit +of its use by man in actual aerial flights have been far +from encouraging. + +Three Kinds of Aeroplanes. + +There are three forms of aeroplanes, with all of which +more or less success has been attained. These are: + +The monoplane, a one-surfaced plane, like that used +by Bleriot. + +The biplane, a two-surfaced plane, now used by the +Wrights, Curtiss, Farman, and others. + +The triplane, a three-surfaced plane This form is +but little used, its only prominent advocate at present +being Elle Lavimer, a Danish experimenter, who has not +thus far accomplished much. + +Whatever of real success has been accomplished in +aviation may be credited to the monoplane and biplane, +with the balance in favor of the latter. The monoplane +is the more simple in construction and, where weight- +sustaining capacity is not a prime requisite, may +probably be found the most convenient. This opinion is +based on the fact that the smaller the surface of the +plane the less will be the resistance offered to the air, +and the greater will be the speed at which the machine +may be moved. On the other hand, the biplane has a +much greater plane surface (double that of a monoplane +of the same size) and consequently much greater weight- +carrying capacity. + +Differences in Biplanes. + +While all biplanes are of the same general construction +so far as the main planes are concerned, each aviator +has his own ideas as to the "rigging." + +Wright, for instance, places a double horizontal rudder +in front, with a vertical rudder in the rear. There +are no partitions between the main planes, and the +bicycle wheels used on other forms are replaced by skids. + +Voisin, on the contrary, divides the main planes with +vertical partitions to increase stability in turning; uses +a single-plane horizontal rudder in front, and a big box- +tail with vertical rudder at the rear; also the bicycle +wheels. + +Curtiss attaches horizontal stabilizing surfaces to the +upper plane; has a double horizontal rudder in front, +with a vertical rudder and horizontal stabilizing surfaces +in rear. Also the bicycle wheel alighting gear. + + + +CHAPTER V. + +CONSTRUCTING A GLIDING MACHINE. + +First decide upon the kind of a machine you want-- +monoplane, biplane, or triplane. For a novice the biplane +will, as a rule, be found the most satisfactory as +it is more compact and therefore the more easily handled. +This will be easily understood when we realize that the +surface of a flying machine should be laid out in proportion +to the amount of weight it will have to sustain. +The generally accepted rule is that 152 square feet of +surface will sustain the weight of an average-sized man, +say 170 pounds. Now it follows that if these 152 square +feet of surface are used in one plane, as in the monoplane, +the length and width of this plane must be greater +than if the same amount of surface is secured by using +two planes--the biplane. This results in the biplane +being more compact and therefore more readily manipulated +than the monoplane, which is an important item +for a novice. + +Glider the Basis of Success. + +Flying machines without motors are called gliders. In +making a flying machine you first construct the glider. +If you use it in this form it remains a glider. If you +install a motor it becomes a flying machine. You must +have a good glider as the basis of a successful flying +machine. + +It will be well for the novice, the man who has never +had any experience as an aviator, to begin with a glider +and master its construction and operation before he +essays the more pretentious task of handling a fully- +equipped flying machine. In fact, it is essential that he +should do so. + +Plans for Handy Glider. + +A glider with a spread (advancing edge) of 20 feet, and +a breadth or depth of 4 feet, will be about right to begin +with. Two planes of this size will give the 152 square +yards of surface necessary to sustain a man's weight. +Remember that in referring to flying machine measurements +"spread" takes the place of what would ordinarily +be called "length," and invariably applies to the long +or advancing edge of the machine which cuts into the air. +Thus, a glider is spoken of as being 20 feet spread, and +4 feet in depth. So far as mastering the control of the +machine is concerned, learning to balance one's self in +the air, guiding the machine in any desired direction by +changing the position of the body, etc., all this may be +learned just as readily, and perhaps more so, with a 20- +foot glider than with a larger apparatus. + +Kind of Material Required. + +There are three all-important features in flying machine +construction, viz.: lightness, strength and extreme +rigidity. Spruce is the wood generally used for glider +frames. Oak, ash and hickory are all stronger, but they +are also considerably heavier, and where the saving of +weight is essential, the difference is largely in favor of +spruce. This will be seen in the following table: + + Weight Tensile Compressive + per cubic ft. Strength Strength + Wood in lbs. lbs. per sq. in. lbs. per sq in. +Hickory 53 12,000 8,500 +Oak 50 12,000 9,000 +Ash 38 12,000 6,000 +Walnut 38 8,000 6,000 +Spruce 25 8,000 5,000 +Pine 25 5,000 4,500 + + +Considering the marked saving in weight spruce has +a greater percentage of tensile strength than any of the +other woods. It is also easier to find in long, straight- +grained pieces free from knots, and it is this kind only +that should be used in flying machine construction. + +You will next need some spools or hanks of No. 6 +linen shoe thread, metal sockets, a supply of strong +piano wire, a quantity of closely-woven silk or cotton +cloth, glue, turnbuckles, varnish, etc. + +Names of the Various Parts. + +The long strips, four in number, which form the front +and rear edges of the upper and lower frames, are called +the horizontal beams. These are each 20 feet in length. +These horizontal beams are connected by upright strips, +4 feet long, called stanchions. There are usually 12 of +these, six on the front edge, and six on the rear. They +serve to hold the upper plane away from the lower one. +Next comes the ribs. These are 4 feet in length (projecting +for a foot over the rear beam), and while intended +principally as a support to the cloth covering of +the planes, also tend to hold the frame together in a +horizontal position just as the stanchions do in the vertical. +There are forty-one of these ribs, twenty-one on +the upper and twenty on the lower plane. Then come +the struts, the main pieces which join the horizontal +beams. All of these parts are shown in the illustrations, +reference to which will make the meaning of the +various names clear. + +Quantity and Cost of Material. + +For the horizontal beams four pieces of spruce, 20 feet +long, 1 1/2 inches wide and 3/4 inch thick are necessary. +These pieces must be straight-grain, and absolutely free +from knots. If it is impossible to obtain clear pieces +of this length, shorter ones may be spliced, but this is +not advised as it adds materially to the weight. The +twelve stanchions should be 4 feet long and 7/8 inch in +diameter and rounded in form so as to offer as little +resistance as possible to the wind. The struts, there +are twelve of them, are 3 feet long by 11/4 x 1/2 inch. For +a 20-foot biplane about 20 yards of stout silk or unbleached +muslin, of standard one yard width, will be +needed. The forty-one ribs are each 4 feet long, and +1/2 inch square. A roll of No. 12 piano wire, twenty-four +sockets, a package of small copper tacks, a pot of glue, +and similar accessories will be required. The entire +cost of this material should not exceed $20. The wood +and cloth will be the two largest items, and these should +not cost more than $10. This leaves $10 for the varnish, +wire, tacks, glue, and other incidentals. This estimate +is made for cost of materials only, it being taken for +granted that the experimenter will construct his own +glider. Should the services of a carpenter be required +the total cost will probably approximate $60 or $70. + +Application of the Rudders. + +The figures given also include the expense of rudders, +but the details of these have not been included as the +glider is really complete without them. Some of the best +flights the writer ever saw were made by Mr. A. M. Herring in a +glider without a rudder, and yet there can +be no doubt that a rudder, properly proportioned and +placed, especially a rear rudder, is of great value to the +aviator as it keeps the machine with its head to the +wind, which is the only safe position for a novice. For +initial educational purposes, however, a rudder is not +essential as the glides will, or should, be made on level +ground, in moderate, steady wind currents, and at a +modest elevation. The addition of a rudder, therefore, +may well be left until the aviator has become reasonably +expert in the management of his machine. + +Putting the Machine Together. + +Having obtained the necessary material, the first move +is to have the rib pieces steamed and curved. This curve +may be slight, about 2 inches for the 4 feet. While +this is being done the other parts should be carefully +rounded so the square edges will be taken off. This +may be done with sand paper. Next apply a coat of +shellac, and when dry rub it down thoroughly with fine +sand paper. When the ribs are curved treat them in +the same way. + +Lay two of the long horizontal frame pieces on the +floor 3 feet apart. Between these place six of the strut +pieces. Put one at each end, and each 4 1/2 feet put +another, leaving a 2-foot space in the center. This will +give you four struts 4 1/2 feet apart, and two in the center +2 feet apart, as shown in the illustration. This makes +five rectangles. Be sure that the points of contact are +perfect, and that the struts are exactly at right angles +with the horizontal frames. This is a most important +feature because if your frame "skews" or twists you +cannot keep it straight in the air. Now glue the ends +of the struts to the frame pieces, using plenty of glue, +and nail on strips that will hold the frame in place while +the glue is drying. The next day lash the joints together +firmly with the shoe thread, winding it as you would to +mend a broken gun stock, and over each layer put a +coating of glue. This done, the other frame pieces and +struts may be treated in the same way, and you will thus +get the foundations for the two planes. + +Another Way of Placing Struts. + +In the machines built for professional use a stronger +and more certain form of construction is desired. This +is secured by the placing the struts for the lower plane +under the frame piece, and those for the upper plane +over it, allowing them in each instance to come out flush +with the outer edges of the frame pieces. They are then +securely fastened with a tie plate or clamp which passes +over the end of the strut and is bound firmly against +the surface of the frame piece by the eye bolts of the +stanchion sockets. + +Placing the Rib Pieces. + +Take one of the frames and place on it the ribs, with +the arched side up, letting one end of the ribs come +flush with the front edge of the forward frame, and the +other end projecting about a foot beyond the rear frame. +The manner of fastening the ribs to the frame pieces is +optional. In some cases they are lashed with shoe +thread, and in others clamped with a metal clamp fastened +with 1/2-inch wood screws. Where clamps and +screws are used care should be taken to make slight +holes in the wood with an awl before starting the screws +so as to lessen any tendency to split the wood. On the +top frame, twenty-one ribs placed one foot apart will be +required. On the lower frame, because of the opening +left for the operator's body, you will need only twenty. + +Joining the Two Frames. + +The two frames must now be joined together. For this +you will need twenty-four aluminum or iron sockets +which may be purchased at a foundry or hardware shop. +These sockets, as the name implies, provide a receptacle +in which the end of a stanchion is firmly held, and have +flanges with holes for eye-bolts which hold them firmly +to the frame pieces, and also serve to hold the guy wires. +In addition to these eye-bolt holes there are two others +through which screws are fastened into the frame pieces. +On the front frame piece of the bottom plane place six +sockets, beginning at the end of the frame, and locating +them exactly opposite the struts. Screw the sockets into +position with wood screws, and then put the eye-bolts in +place. Repeat the operation on the rear frame. Next +put the sockets for the upper plane frame in place. + +You are now ready to bring the two planes together. +Begin by inserting the stanchions in the sockets in the +lower plane. The ends may need a little rubbing with +sandpaper to get them into the sockets, but care must +be taken to have them fit snugly. When all the stanchions +are in place on the lower plane, lift the upper +plane into position, and fit the sockets over the upper +ends of the stanchions. + +Trussing with Guy Wires. + +The next move is to "tie" the frame together rigidly +by the aid of guy wires. This is where the No. 12 piano +wire comes in. Each rectangle formed by the struts and +stanchions with the exception of the small center one, +is to be wired separately as shown in the illustration. +At each of the eight corners forming the rectangle the +ring of one of the eye-bolts will be found. There are +two ways of doing this "tieing," or trussing. One is to +run the wires diagonally from eye-bolt to eye-bolt, depending +upon main strength to pull them taut enough, +and then twist the ends so as to hold. The other is to +first make a loop of wire at each eye-bolt, and connect +these loops to the main wires with turn-buckles. This +latter method is the best, as it admits of the tension being +regulated by simply turning the buckle so as to draw +the ends of the wire closer together. A glance at the +illustration will make this plain, and also show how the +wires are to be placed. The proper degree of tension +may be determined in the following manner: + +After the frame is wired place each end on a saw-horse +so as to lift the entire frame clear of the work-shop +floor. Get under it, in the center rectangle and, grasping +the center struts, one in each hand, put your entire +weight on the structure. If it is properly put together +it will remain rigid and unyielding. Should it sag ever +so slightly the tension of the wires must be increased +until any tendency to sag, no matter how slight it may +be, is overcome. + +Putting on the Cloth. + +We are now ready to put on the cloth covering which +holds the air and makes the machine buoyant. The kind +of material employed is of small account so long as it is +light, strong, and wind-proof, or nearly so. Some aviators +use what is called rubberized silk, others prefer +balloon cloth. Ordinary muslin of good quality, treated +with a coat of light varnish after it is in place, will answer +all the purposes of the amateur. + +Cut the cloth into strips a little over 4 feet in length. +As you have 20 feet in width to cover, and the cloth is +one yard wide, you will need seven strips for each plane, +so as to allow for laps, etc. This will give you fourteen +strips. Glue the end of each strip around the front +horizontal beams of the planes, and draw each strip back, +over the ribs, tacking the edges to the ribs as you go +along, with small copper or brass tacks. In doing this +keep the cloth smooth and stretched tight. Tacks should +also be used in addition to the glue, to hold the cloth to +the horizontal beams. + +Next, give the cloth a coat of varnish on the clear, or +upper side, and when this is dry your glider will be +ready for use. + +Reinforcing the Cloth. + +While not absolutely necessary for amateur purposes, +reinforcement of the cloth, so as to avoid any tendency +to split or tear out from wind-pressure, is desirable. One +way of doing this is to tack narrow strips of some +heavier material, like felt, over the cloth where it laps +on the ribs. Another is to sew slips or pockets in the +cloth itself and let the ribs run through them. Still another +method is to sew 2-inch strips (of the same material +as the cover) on the cloth, placing them about one +yard apart, but having them come in the center of each +piece of covering, and not on the laps where the various +pieces are joined. + +Use of Armpieces. + +Should armpieces be desired, aside from those afforded +by the center struts, take two pieces of spruce, 3 feet +long, by 1 x 1 3/4 inches, and bolt them to the front and +rear beams of the lower plane about 14 inches apart. +These will be more comfortable than using the struts, +as the operator will not have to spread his arms so +much. In using the struts the operator, as a rule, takes +hold of them with his hands, while with the armpieces, +as the name implies, he places his arms over them, one +of the strips coming under each armpit. + +Frequently somebody asks why the ribs should be +curved. The answer is easy. The curvature tends to +direct the air downward toward the rear and, as the air +is thus forced downward, there is more or less of an impact +which assists in propelling the aeroplane upwards. + + + +CHAPTER VI. + +LEARNING TO FLY. + +Don't be too ambitious at the start. Go slow, and +avoid unnecessary risks. At its best there is an element +of danger in aviation which cannot be entirely eliminated, but it +may be greatly reduced and minimized by +the use of common sense. + +Theoretically, the proper way to begin a glide is from +the top of an incline, facing against the wind, so that +the machine will soar until the attraction of gravitation +draws it gradually to the ground. This is the manner in +which experienced aviators operate, but it must be kept +in mind that these men are experts. They understand +air currents, know how to control the action and direction +of their machines by shifting the position of their +bodies, and by so doing avoid accidents which would be +unavoidable by a novice. + +Begin on Level Ground. + +Make your first flights on level ground, having a couple +of men to assist you in getting the apparatus under +headway. Take your position in the center rectangle, +back far enough to give the forward edges of the glider +an inclination to tilt upward very slightly. Now start +and run forward at a moderately rapid gait, one man at +each end of the glider assisting you. As the glider cuts +into the air the wind will catch under the uplifted edges +of the curved planes, and buoy it up so that it will rise +in the air and take you with it. This rise will not be +great, just enough to keep you well clear of the ground. +Now project your legs a little to the front so as to shift +the center of gravity a trifle and bring the edges of the +glider on an exact level with the atmosphere. This, with +the momentum acquired in the start, will keep the machine +moving forward for some distance. + +Effect of Body Movements. + +When the weight of the body is slightly back of the +center of gravity the edges of the advancing planes are +tilted slightly upward. The glider in this position acts +as a scoop, taking in the air which, in turn, lifts it off the +ground. When a certain altitude is reached--this varies +with the force of the wind--the tendency to a forward +movement is lost and the glider comes to the ground. +It is to prolong the forward movement as much as possible +that the operator shifts the center of gravity slightly, +bringing the apparatus on an even keel as it were by +lowering the advancing edges. This done, so long as +there is momentum enough to keep the glider moving, it +will remain afloat. + +If you shift your body well forward it will bring the +front edges of the glider down, and elevate the rear ones. +In this way the air will be "spilled" out at the rear, and, +having lost the air support or buoyancy, the glider comes +down to the ground. A few flights will make any ordinary +man proficient in the control of his apparatus by his +body movements, not only as concerns the elevating and +depressing of the advancing edges, but also actual steering. You +will quickly learn, for instance, that, as the +shifting of the bodily weight backwards and forwards +affects the upward and downward trend of the planes, so +a movement sideways--to the left or the right--affects +the direction in which the glider travels. + +Ascends at an Angle. + +In ascending, the glider and flying machine, like the +bird, makes an angular, not a vertical flight. Just what +this angle of ascension may be is difficult to determine. +It is probable and in fact altogether likely, that it varies +with the force of the wind, weight of the rising body, +power of propulsion, etc. This, in the language of physicists, +is the angle of inclination, and, as a general thing, +under normal conditions (still air) should be put down as +about one in ten, or 5 3/4 degrees. This would be an ideal +condition, but it has not, as vet been reached. The force +of the wind affects the angle considerably, as does also +the weight and velocity of the apparatus. In general +practice the angle varies from 23 to 45 degrees. At +more than 45 degrees the supporting effort is overcome +by the resistance to forward motion. + +Increasing the speed or propulsive force, tends to +lessen the angle at which the machine may be successfully +operated because it reduces the wind pressure. +Most of the modern flying machines are operated at an +angle of 23 degrees, or less. + +Maintaining an Equilibrium. + +Stable equilibrium is one of the main essentials to +successful flight, and this cannot be preserved in an +uncertain, gusty wind, especially by an amateur. The +novice should not attempt a glide unless the conditions +are just right. These conditions are: A clear, level +space, without obstructions, such as trees, etc., and a +steady wind of not exceeding twelve miles an hour. Always +fly against the wind. + +When a reasonable amount of proficiency in the handling +of the machine on level ground has been acquired +the field of practice may be changed to some gentle +slope. In starting from a slope it will be found easier +to keep the machine afloat, but the experience at first is +likely to be very disconcerting to a man of less than iron +nerve. As the glider sails away from the top of the +slope the distance between him and the ground increases +rapidly until the aviator thinks he is up a hundred miles +in the air. If he will keep cool, manipulate his apparatus +so as to preserve its equilibrium, and "let nature take its +course," he will come down gradually and safely to the +ground at a considerable distance from the starting place. +This is one advantage of starting from an elevation-- +your machine will go further. + +But, if the aviator becomes "rattled"; if he loses control +of his machine, serious results, including a bad fall +with risk of death, are almost certain. And yet this +practice is just as necessary as the initial lessons on +level ground. When judgment is used, and "haste made +slowly," there is very little real danger. While experimenting +with gliders the Wrights made flights innumerable +under all sorts of conditions and never had an accident +of any kind. + +Effects of Wind Currents. + +The larger the machine the more difficult it will be to +control its movements in the air, and yet enlargement is +absolutely necessary as weight, in the form of motor, +rudder, etc., is added. + +Air currents near the surface of the ground are diverted +by every obstruction unless the wind is blowing +hard enough to remove the obstruction entirely. Take, +for instance, the case of a tree or shrub, in a moderate +wind of from ten to twelve miles an hour. As the wind +strikes the tree it divides, part going to one side and +part going to the other, while still another part is directed +upward and goes over the top of the obstruction. +This makes the handling of a glider on an obstructed +field difficult and uncertain. To handle a glider successfully +the place of operation should be clear and the wind +moderate and steady. If it is gusty postpone your flight. +In this connection it will be well to understand the velocity +of the wind, and what it means as shown in the +following table: + +Miles per hour Feet per second Pressure per sq. foot + 10 14.7 .492 + 25 36.7 3.075 + 50 73.3 12.300 + 100 146.6 49.200 + +Pressure of wind increases in proportion to the square +of the velocity. Thus wind at 10 miles an hour has four +times the pressure of wind at 5 miles an hour. The +greater this pressure the large and heavier the object +which can be raised. Any boy who has had experience +in flying kites can testify to this, High winds, however, +are almost invariably gusty and uncertain as to direction, +and this makes them dangerous for aviators. It +is also a self-evident fact that, beyond a certain stage, +the harder the wind blows the more difficult it is to +make headway against it. + +Launching Device for Gliders. + +On page 195 will be found a diagram of the various +parts of a launcher for gliders, designed and patented +by Mr. Octave Chanute. In describing this invention +in Aeronautics, Mr. Chanute says: + +"In practicing, the track, preferably portable, is +generally laid in the direction of the existing wind and +the car, preferably a light platform-car, is placed on the +track. The truck carrying the winding-drum and its motor +is placed to windward a suitable distance--say from +two hundred to one thousand feet--and is firmly blocked +or anchored in line with the portable track, which is +preferably 80 or 100 feet in length. The flying or gliding +machine to be launched with its operator is placed on +the platform-car at the leeward end of the portable track. +The line, which is preferably a flexible combination +wire-and-cord cable, is stretched between the winding- +drum on the track and detachably secured to the flying +or gliding machine, preferably by means of a trip-hoop, +or else held in the hand of the operator, so that the +operator may readily detach the same from the flying- +machine when the desired height is attained. + +How Glider Is Started. + +"Then upon a signal given by the operator the engineer +at the motor puts it into operation, gradually increasing +the speed until the line is wound upon the drum +at a maximum speed of, say, thirty miles an hour. The +operator of the flying-machine, whether he stands upright and +carries it on his shoulders, or whether he sits +or lies down prone upon it, adjusts the aeroplane or +carrying surfaces so that the wind shall strike them on +the top and press downward instead of upward until +the platform-car under action of the winding-drum and +line attains the required speed. + +"When the operator judges that his speed is sufficient, +and this depends upon the velocity of the wind as well +as that of the car moving against the wind, he quickly +causes the front of the flying-machine to tip upward, so +that the relative wind striking on the under side of the +planes or carrying surfaces shall lift the flying machine +into the air. It then ascends like a kite to such height +as may be desired by the operator, who then trips the +hook and releases the line from the machine. + +What the Operator Does. + +"The operator being now free in the air has a certain +initial velocity imparted by the winding-drum and line +and also a potential energy corresponding to his height +above the ground. If the flying or gliding machine is +provided with a motor, he can utilize that in his further +flight, and if it is a simple gliding machine without +motor he can make a descending flight through the air +to such distance as corresponds to the velocity acquired +and the height gained, steering meanwhile by the devices +provided for that purpose. + +"The simplest operation or maneuver is to continue +the flight straight ahead against the wind; but it is possible +to vary this course to the right or left, or even to +return in downward flight with the wind to the vicinity +of the starting-point. Upon nearing the ground the +operator tips upward his carrying-surfaces and stops his +headway upon the cushion of increased air resistance +so caused. The operator is in no way permanently +fastened to his machine, and the machine and the operator +simply rest upon the light platform-car, so that +the operator is free to rise with the machine from the +car whenever the required initial velocity is attained. + +Motor For the Launcher. + +"The motor may be of any suitable kind or construction, +but is preferably an electric or gasolene motor. +The winding-drum is furnished with any suitable or customary +reversing-guide to cause the line to wind smoothly +and evenly upon the drum. The line is preferably a +cable composed of flexible wire and having a cotton or +other cord core to increase its flexibility. The line +extends from the drum to the flying or gliding machine. +Its free end may, if desired, be grasped and held by the +operator until the flying-machine ascends to the desired +height, when by simply letting go of the line the operator +may continue his flight free. The line, however, is preferably +connected to the flying or gliding machine +directly by a trip-hook having a handle or trip lever +within reach of the operator, so that when he ascends +to the required height he may readily detach the line +from the flying or gliding machine." + + + +CHAPTER VII. + +PUTTING ON THE RUDDER. + +Gliders as a rule have only one rudder, and this is in +the rear. It tends to keep the apparatus with its head to +the wind. Unlike the rudder on a boat it is fixed and +immovable. The real motor-propelled flying machine, +generally has both front and rear rudders manipulated +by wire cables at the will of the operator. + +Allowing that the amateur has become reasonably expert +in the manipulation of the glider he should, before +constructing an actual flying machine, equip his glider +with a rudder. + +Cross Pieces for Rudder Beam. + +To do this he should begin by putting in a cross piece, +2 feet long by 1/4x3/4 inches between the center struts, +in the lower plane. This may be fastened to the struts +with bolts or braces. The former method is preferable. +On this cross piece, and on the rear frame of the plane +itself, the rudder beam is clamped and bolted. This +rudder beam is 8 feet 11 inches long. Having put these +in place duplicate them in exactly the same manner and +dimensions from the upper frame The cross pieces on +which the ends of the rudder beams are clamped should +be placed about one foot in advance of the rear frame +beam. + +The Rudder Itself. + +The next step is to construct the rudder itself. This +consists of two sections, one horizontal, the other vertical. +The latter keeps the aeroplane headed into the wind, +while the former keeps it steady--preserves the equilibrium. + +The rudder beams form the top and bottom frames of +the vertical rudder. To these are bolted and clamped +two upright pieces, 3 feet, 10 inches in length, and 3/4 +inch in cross section. These latter pieces are placed about +two feet apart. This completes the framework of the +vertical rudder. See next page (59). + +For the horizontal rudder you will require two strips +6 feet long, and four 2 feet long. Find the exact center +of the upright pieces on the vertical rudder, and at this +spot fasten with bolts the long pieces of the horizontal, +placing them on the outside of the vertical strips. Next +join the ends of the horizontal strips with the 2-foot +pieces, using small screws and corner braces. This done +you will have two of the 2-foot pieces left. These go in +the center of the horizontal frame, "straddling" the +vertical strips, as shown in the illustration. + +The framework is to be covered with cloth in the +same manner as the planes. For this about ten yards +will be needed. + +Strengthening the Rudder. + +To ensure rigidity the rudder must be stayed with +guy wires. For this purpose the No. 12 piano wire is +the best. Begin by running two of these wires from the +top eye-bolts of stanchions 3 and 4, page 37, to rudder +beam where it joins the rudder planes, fastening them +at the bottom. Then run two wires from the top of the +rudder beam at the same point, to the bottom eye-bolts +of the same stanchions. This will give you four diagonal +wires reaching from the rudder beam to the top +and bottom planes of the glider. Now, from the outer +ends of the rudder frame run four similar diagonal wires +to the end of the rudder beam where it rests on the +cross piece. You will then have eight truss wires +strengthening the connection of the rudder to the main +body of the glider. + +The framework of the rudder planes is then to be +braced in the same way, which will take eight more +wires, four for each rudder plane. All the wires are +to be connected at one end with turn-buckles so the +tension may be regulated as desired. + +In forming the rudder frame it will be well to mortise +the corners, tack them together with small nails, and +then put in a corner brace in the inside of each joint. +In doing this bear in mind that the material to be thus +fastened is light, and consequently the lightest of nails, +screws, bolts and corner pieces, etc., is necessary. + + + +CHAPTER VIII. + +THE REAL FLYING MACHINE. + +We will now assume that you have become proficient +enough to warrant an attempt at the construction of a +real flying machine--one that will not only remain suspended +in the air at the will of the operator, but make +respectable progress in whatever direction he may desire to go. +The glider, it must be remembered, is not +steerable, except to a limited extent, and moves only in +one direction--against the wind. Besides this its power +of flotation--suspension in the air--is circumscribed. + +Larger Surface Area Required. + +The real flying machine is the glider enlarged, and +equipped with motor and propeller. The first thing to +do is to decide upon the size required. While a glider +of 20 foot spread is large enough to sustain a man it +could not under any possible conditions, be made to rise +with the weight of the motor, propeller and similar +equipment added. As the load is increased so must the +surface area of the planes be increased. Just what this +increase in surface area should be is problematical as +experienced aviators disagree, but as a general proposition +it may be placed at from three to four times the area of +a 20-foot glider.[3] + +[3] See Chapter XXV. + +Some Practical Examples. + +The Wrights used a biplane 41 feet in spread, and 6 1/2 +ft. deep. This, for the two planes, gives a total surface +area of 538 square feet, inclusive of auxiliary planes. +This sustains the engine equipment, operator, etc., a total +weight officially announced at 1,070 pounds. It shows +a lifting capacity of about two pounds to the square +foot of plane surface, as against a lifting capacity of +about 1/2 pound per square foot of plane surface for the +20-foot glider. This same Wright machine is also reported +to have made a successful flight, carrying a total +load of 1,100 pounds, which would be over two pounds +for each square foot of surface area, which, with auxiliary +planes, is 538 square feet. + +To attain the same results in a monoplane, the single +surface would have to be 60 feet in spread and 9 feet +deep. But, while this is the mathematical rule, Bleriot +has demonstrated that it does not always hold good. +On his record-breaking trip across the English channel, +July 25th, 1909, the Frenchman was carried in a +monoplane 24 1/2 feet in spread, and with a total sustaining +surface of 150 1/2 square feet. The total weight of +the outfit, including machine, operator and fuel sufficient +for a three-hour run, was only 660 pounds. With +an engine of (nominally) 25 horsepower the distance of +21 miles was covered in 37 minutes. + +Which is the Best? + +Right here an established mathematical quantity is +involved. A small plane surface offers less resistance +to the air than a large one and consequently can attain +a higher rate of speed. As explained further on in this +chapter speed is an important factor in the matter of +weight-sustaining capacity. A machine that travels one- +third faster than another can get along with one-half the +surface area of the latter without affecting the load. See +the closing paragraph of this chapter on this point. In +theory the construction is also the simplest, but this is +not always found to be so in practice. The designing +and carrying into execution of plans for an extensive +area like that of a monoplane involves great skill and +cleverness in getting a framework that will be strong +enough to furnish the requisite support without an undue excess +of weight. This proposition is greatly simplified +in the biplane and, while the speed attained by the latter +may not be quite so great as that of the monoplane, it +has much larger weight-carrying capacity. + +Proper Sizes For Frame. + +Allowing that the biplane form is selected the construction +may be practically identical with that of the +20-foot glider described in Chapter V., except as to size +and elimination of the armpieces. In size the surface +planes should be about twice as large as those of the +20-foot glider, viz: 40 feet spread instead of 20, and 6 feet +deep instead of 3. The horizontal beams, struts, stanchions, +ribs, etc., should also be increased in size proportionately. + +While care in the selection of clear, straight-grained +timber is important in the glider, it is still more important +in the construction of a motor-equipped flying +machine as the strain on the various parts will be much +greater. + +How to Splice Timbers. + +It is practically certain that you will have to resort to +splicing the horizontal beams as it will be difficult, if not +impossible, to find 40-foot pieces of timber totally free +from knots and worm holes, and of straight grain. + +If splicing is necessary select two good 20-foot pieces, +3 inches wide and 1 1/2 inches thick, and one 10-foot long, +of the same thickness and width. Plane off the bottom +sides of the 10-foot strip, beginning about two feet back +from each end, and taper them so the strip will be about +3/4 inch thick at the extreme ends. Lay the two 20-foot +beams end to end, and under the joint thus made place +the 10-foot strip, with the planed-off ends downward. +The joint of the 20-foot pieces should be directly in the +center of the 10-foot piece. Bore ten holes (with a 1/4- +inch augur) equi-distant apart through the 20-foot +strips and the 10-foot strip under them. Through these +holes run 1/4-inch stove bolts with round, beveled heads. +In placing these bolts use washers top and bottom, one +between the head and the top beam, and the other between +the bottom beam and the screw nut which holds +the bolt. Screw the nuts down hard so as to bring the +two beams tightly together, and you will have a rigid +40-foot beam. + +Splicing with Metal Sleeves. + +An even better way of making a splice is by tonguing +and grooving the ends of the frame pieces and enclosing +them in a metal sleeve, but it requires more mechanical +skill than the method first named. The operation of +tonguing and grooving is especially delicate and calls +for extreme nicety of touch in the handling of tools, but +if this dexterity is possessed the job will be much more +satisfactory than one done with a third timber. + +As the frame pieces are generally about 1 1/2 inch in +diameter, the tongue and the groove into which the +tongue fits must be correspondingly small. Begin by +sawing into one side of one of the frame pieces about 4 +inches back from the end. Make the cut about 1/2 inch +deep. Then turn the piece over and duplicate the cut. +Next saw down from the end to these cuts. When the +sawed-out parts are removed you will have a "tongue" +in the end of the frame timber 4 inches long and 1/2 inch +thick. The next move is to saw out a 5/8-inch groove in +the end of the frame piece which is to be joined. You +will have to use a small chisel to remove the 5/8-inch bit. +This will leave a groove into which the tongue will fit +easily. + +Joining the Two Pieces. + +Take a thin metal sleeve--this is merely a hollow tube +of aluminum or brass open at each end--8 inches long, +and slip it over either the tongued or grooved end of one +of the frame timbers. It is well to have the sleeve fit +snugly, and this may necessitate a sand-papering of the +frame pieces so the sleeve will slip on. + +Push the sleeve well back out of the way. Cover the +tongue thoroughly with glue, and also put some on the +inside of the groove. Use plenty of glue. Now press +the tongue into the groove, and keep the ends firmly +together until the glue is thoroughly dried. Rub off the +joint lightly with sand-paper to remove any of the glue +which may have oozed out, and slip the sleeve into place +over the joint. Tack the sleeve in position with small +copper tacks, and you will have an ideal splice. + +The same operation is to be repeated on each of the +four frame pieces. Two 20-foot pieces joined in this +way will give a substantial frame, but when suitable +timber of this kind can not be had, three pieces, each 6 +feet 11 inches long, may be used. This would give 20 +feet 9 inches, of which 8 inches will be taken up in the +two joints, leaving the frame 20 feet 1 inch long. + +Installation of Motor. + +Next comes the installation of the motor. The kinds +and efficiency of the various types are described in the +following chapter (IX). All we are interested in at +this point is the manner of installation. This varies +according to the personal ideas of the aviator. Thus one +man puts his motor in the front of his machine, another +places it in the center, and still another finds the rear of +the frame the best. All get good results, the comparative +advantages of which it is difficult to estimate. Where +one man, as already explained, flies faster than another, +the one beaten from the speed standpoint has an advantage +in the matter of carrying weight, etc. + +The ideas of various well-known aviators as to the +correct placing of motors may be had from the following: + +Wrights--In rear of machine and to one side. + +Curtiss--Well to rear, about midway between upper +and lower planes. + +Raich--In rear, above the center. + +Brauner-Smith--In exact center of machine. + +Van Anden--In center. + +Herring-Burgess--Directly behind operator. + +Voisin--In rear, and on lower plane. + +Bleriot--In front. + +R. E. P.--In front. + +The One Chief Object. + +An even distribution of the load so as to assist in +maintaining the equilibrium of the machine, should be +the one chief object in deciding upon the location of the +motor. It matters little what particular spot is selected +so long as the weight does not tend to overbalance the +machine, or to "throw it off an even keel." It is just +like loading a vessel, an operation in which the expert +seeks to so distribute the weight of the cargo as to keep +the vessel in a perfectly upright position, and prevent a +"list" or leaning to one side. The more evenly the cargo +is distributed the more perfect will be the equilibrium of +the vessel and the better it can be handled. Sometimes, +when not properly stowed, the cargo shifts, and this at +once affects the position of the craft. When a ship +"lists" to starboard or port a preponderating weight of +the cargo has shifted sideways; if bow or stern is unduly +depressed it is a sure indication that the cargo has shifted +accordingly. In either event the handling of the craft +becomes not only difficult, but extremely hazardous. +Exactly the same conditions prevail in the handling of a +flying machine. + +Shape of Machine a Factor. + +In placing the motor you must be governed largely by +the shape and construction of the flying machine frame. +If the bulk of the weight of the machine and auxiliaries +is toward the rear, then the natural location for the motor +will be well to the front so as to counterbalance the +excess in rear weight. In the same way if the +preponderance of the weight is forward, then the motor +should be placed back of the center. + +As the propeller blade is really an integral part of the +motor, the latter being useless without it, its placing +naturally depends upon the location selected for the +motor. + +Rudders and Auxiliary Planes. + +Here again there is great diversity of opinion among +aviators as to size, location and form. The striking +difference of ideas in this respect is well illustrated in +the choice made by prominent makers as follows: + +Voisin--horizontal rudder, with two wing-like planes, +in front; box-like longitudinal stability plane in rear, +inside of which is a vertical rudder. + +Wright--large biplane horizontal rudder in front at +considerable distance--about 10 feet--from the main +planes; vertical biplane rudder in rear; ends of upper +and lower main planes made flexible so they may be +moved. + +Curtiss--horizontal biplane rudder, with vertical damping +plane between the rudder planes about 10 feet in +front of main planes; vertical rudder in rear; stabilizing +planes at each end of upper main plane. + +Bleriot--V-shaped stabilizing fin, projecting from rear +of plane, with broad end outward; to the broad end of +this fin is hinged a vertical rudder; horizontal biplane +rudder, also in rear, under the fin. + +These instances show forcefully the wide diversity of +opinion existing among experienced aviators as to the +best manner of placing the rudders and stabilizing, or +auxiliary planes, and make manifest how hopeless would +be the task of attempting to select any one form and +advise its exclusive use. + +Rudder and Auxiliary Construction. + +The material used in the construction of the rudders +and auxiliary planes is the same as that used in the main +planes--spruce for the framework and some kind of +rubberized or varnished cloth for the covering. The +frames are joined and wired in exactly the same manner +as the frames of the main planes, the purpose being to +secure the same strength and rigidity. Dimensions of +the various parts depend upon the plan adopted and the +size of the main plane. + +No details as to exact dimensions of these rudders and +auxiliary planes are obtainable. The various builders, +while willing enough to supply data as to the general +measurements, weight, power, etc., of their machines, +appear to have overlooked the details of the auxiliary +parts, thinking, perhaps, that these were of no particular +import to the general public. In the Wright machine, the +rear horizontal and front vertical rudders may be set +down as being about one-quarter (probably a little less) +the size of the main supporting planes. + +Arrangement of Alighting Gear. + +Most modern machines are equipped with an alighting +gear, which not only serves to protect the machine and +aviator from shock or injury in touching the ground, but +also aids in getting under headway. All the leading +makes, with the exception of the Wright, are furnished +with a frame carrying from two to five pneumatic rubber- +tired bicycle wheels. In the Curtiss and Voisin +machines one wheel is placed in front and two in the +rear. In the Bleriot and other prominent machines the +reverse is the rule--two wheels in front and one in the +rear. Farman makes use of five wheels, one in the, +extreme rear, and four, arranged in pairs, a little to the +front of the center of the main lower plane. + +In place of wheels the Wright machine is equipped +with a skid-like device consisting of two long beams +attached to the lower plane by stanchions and curving +up far in front, so as to act as supports to the horizontal +rudder. + +Why Wood Is Favored. + +A frequently asked question is: "Why is not aluminum, +or some similar metal, substituted for wood." +Wood, particularly spruce, is preferred because, weight +considered, it is much stronger than aluminum, and this +is the lightest of all metals. In this connection the following +table will be of interest: + + Compressive + Weight Tensile Strength Strength + per cubic foot per sq. inch per sq. inch +Material in lbs. in lbs. in lbs. +Spruce . . . . 25 8,000 5,000 +Aluminum 162 16,000 ...... +Brass (sheet) 510 23,000 12,000 +Steel (tool) 490 100,000 40,000 +Copper (sheet) 548 30,000 40,000 + +As extreme lightness, combined with strength, +especially tensile strength, is the great essential in flying- +machine construction, it can be readily seen that the +use of metal, even aluminum, for the framework, is +prohibited by its weight. While aluminum has double the +strength of spruce wood it is vastly heavier, and thus +the advantage it has in strength is overbalanced many +times by its weight. The specific gravity of aluminum +is 2.50; that of spruce is only 0.403. + +Things to Be Considered. + +In laying out plans for a flying machine there are five +important points which should be settled upon before +the actual work of construction is started. These are: + +First--Approximate weight of the machine when finished +and equipped. + +Second--Area of the supporting surface required. + +Third--Amount of power that will be necessary to +secure the desired speed and lifting capacity. + +Fourth--Exact dimensions of the main framework +and of the auxiliary parts. + +Fifth--Size, speed and character of the propeller. + +In deciding upon these it will be well to take into +consideration the experience of expert aviators regarding +these features as given elsewhere. (See Chapter X.) + +Estimating the Weights Involved. + +In fixing upon the probable approximate weight in +advance of construction much, of course, must be assumed. +This means that it will be a matter of advance +estimating. If a two-passenger machine is to be built +we will start by assuming the maximum combined +weight of the two people to be 350 pounds. Most of +the professional aviators are lighter than this. Taking +the medium between the weights of the Curtiss and +Wright machines we have a net average of 850 pounds +for the framework, motor, propeller, etc. This, with +the two passengers, amounts to 1,190 pounds. As the +machines quoted are in successful operation it will be +reasonable to assume that this will be a safe basis to +operate on. + +What the Novice Must Avoid. + +This does not mean, however, that it will be safe to +follow these weights exactly in construction, but that +they will serve merely as a basis to start from. Because +an expert can turn out a machine, thoroughly equipped, +of 850 pounds weight, it does not follow that a novice +can do the same thing. The expert's work is the result +of years of experience, and he has learned how to construct +frames and motor plants of the utmost lightness +and strength. + +It will be safer for the novice to assume that he can +not duplicate the work of such men as Wright and Curtiss +without adding materially to the gross weight of +the framework and equipment minus passengers. + +How to Distribute the Weight. + +Let us take 1,030 pounds as the net weight of the machine +as against the same average in the Wright and +Curtiss machines. Now comes the question of distributing +this weight between the framework, motor, and +other equipment. As a general proposition the framework +should weigh about twice as much as the complete +power plant (this is for amateur work). + +The word "framework" indicates not only the wooden +frames of the main planes, auxiliary planes, rudders, +etc., but the cloth coverings as well--everything in fact +except the engine and propeller. + +On the basis named the framework would weigh 686 +pounds, and the power plant 344. These figures are +liberal, and the results desired may be obtained well +within them as the novice will learn as he makes progress +in the work. + +Figuring on Surface Area. + +It was Prof. Langley who first brought into prominence +in connection with flying machine construction the +mathematical principle that the larger the object the +smaller may be the relative area of support. As explained +in Chapter XIII, there are mechanical limits as +to size which it is not practical to exceed, but the main +principle remains in effect. + +Take two aeroplanes of marked difference in area of +surface. The larger will, as a rule, sustain a greater +weight in relative proportion to its area than the smaller +one, and do the work with less relative horsepower. As +a general thing well-constructed machines will average +a supporting capacity of one pound for every one-half +square foot of surface area. Accepting this as a working +rule we find that to sustain a weight of 1,200 pounds +--machine and two passengers--we should have 600 +square feet of surface. + +Distributing the Surface Area. + +The largest surfaces now in use are those of the +Wright, Voisin and Antoinette machines--538 square +feet in each. The actual sustaining power of these machines, +so far as known, has never been tested to the +limit; it is probable that the maximum is considerably +in excess of what they have been called upon to show. +In actual practice the average is a little over one pound +for each one-half square foot of surface area. + +Allowing that 600 square feet of surface will be used, +the next question is how to distribute it to the best +advantage. This is another important matter in which +individual preference must rule. We have seen how +the professionals disagree on this point, some using +auxiliary planes of large size, and others depending upon +smaller auxiliaries with an increase in number so as to +secure on a different plan virtually the same amount of +surface. + +In deciding upon this feature the best thing to do is +to follow the plans of some successful aviator, increasing +the area of the auxiliaries in proportion to the increase +in the area of the main planes. Thus, if you use 600 +square feet of surface where the man whose plans you +are following uses 500, it is simply a matter of making +your planes one-fifth larger all around. + +The Cost of Production. + +Cost of production will be of interest to the amateur +who essays to construct a flying machine. Assuming +that the size decided upon is double that of the glider +the material for the framework, timber, cloth, wire, etc., +will cost a little more than double. This is because it +must be heavier in proportion to the increased size of +the framework, and heavy material brings a larger price +than the lighter goods. If we allow $20 as the cost of +the glider material it will be safe to put down the cost +of that required for a real flying machine framework +at $60, provided the owner builds it himself. + +As regards the cost of motor and similar equipment +it can only be said that this depends upon the selection +made. There are some reliable aviation motors which +may be had as low as $500, and there are others which +cost as much as $2,000. + +Services of Expert Necessary. + +No matter what kind of a motor may be selected the +services of an expert will be necessary in its proper +installation unless the amateur has considerable genius +in this line himself. As a general thing $25 should be +a liberal allowance for this work. No matter how carefully +the engine may be placed and connected it will be +largely a matter of luck if it is installed in exactly the +proper manner at the first attempt. The chances are +that several alterations, prompted by the results of trials, +will have to be made. If this is the case the expert's bill may +readily run up to $50. If the amateur is competent to do this +part of the work the entire item of $50 may, of course, be cut +out. + +As a general proposition a fairly satisfactory flying machine, +one that will actually fly and carry the operator with it, may be +constructed for $750, but it will lack the better qualities which +mark the higher priced machines. This computation is made on +the basis of $60 for material, $50 for services of expert, $600 +for motor, etc., and an allowance of $40 for extras. + +No man who has the flying machine germ in his system will be long +satisfied with his first moderate price machine, no matter how +well it may work. It's the old story of the automobile "bug" +over again. The man who starts in with a modest $1,000 automobile +invariably progresses by easy stages to the $4,000 or $5,000 +class. The natural tendency is to want the biggest and best +attainable within the financial reach of the owner. + +It's exactly the same way with the flying machine +convert. The more proficient he becomes in the manipulation +of his car, the stronger becomes the desire to fly +further and stay in the air longer than the rest of his +brethren. This necessitates larger, more powerful, and +more expensive machines as the work of the germ progresses. + +Speed Affects Weight Capacity. + +Don't overlook the fact that the greater speed you +can attain the smaller will be the surface area you can +get along with. If a machine with 500 square feet of +sustaining surface, traveling at a speed of 40 miles an +hour, will carry a weight of 1,200 pounds, we can cut +the sustaining surface in half and get along with 250 +square feet, provided a speed of 60 miles an hour can +be obtained. At 100 miles an hour only 80 square feet +of surface area would be required. In both instances the +weight sustaining capacity will remain the same as with +the 500 square feet of surface area--1,200 pounds. + +One of these days some mathematical genius will +figure out this problem with exactitude and we will have +a dependable table giving the maximum carrying capacity +of various surface areas at various stated speeds, +based on the dimensions of the advancing edges. At +present it is largely a matter of guesswork so far as +making accurate computation goes. Much depends upon +the shape of the machine, and the amount of surface +offering resistance to the wind, etc. + + + +CHAPTER IX. + +SELECTION OF THE MOTOR. + +Motors for flying machines must be light in weight, +of great strength, productive of extreme speed, and +positively dependable in action. It matters little +as to the particular form, or whether air or +water cooled, so long as the four features named are +secured. There are at least a dozen such motors or +engines now in use. All are of the gasolene type, and +all possess in greater or lesser degree the desired qualities. +Some of these motors are: + +Renault--8-cylinder, air-cooled; 50 horse power; +weight 374 pounds. + +Fiat--8-cylinder, air-cooled; 50 horse power; weight +150 pounds. + +Farcot--8-cylinder, air-cooled; from 30 to 100 horse +power, according to bore of cylinders; weight of smallest, +84 pounds. + +R. E. P.--10-cylinder, air-cooled; 150 horse power; +weight 215 pounds. + +Gnome--7 and 14 cylinders, revolving type, air-cooled; +50 and 100 horse power; weight 150 and 300 pounds. + +Darracq--2 to 14 cylinders, water cooled; 30 to 200 +horse power; weight of smallest 100 pounds. + +Wright--4-cylinder, water-cooled; 25 horse power; +weight 200 pounds. + +Antoinette--8 and 16-cylinder, water-cooled; 50 and 100 +horse power; weight 250 and 500 pounds. + +E. N. V.--8-cylinder, water-cooled; from 30 to 80 +horse power, according to bore of cylinder; weight 150 +to 400 pounds. + +Curtiss--8-cylinder, water-cooled; 60 horse power; +weight 300 pounds. + +Average Weight Per Horse Power. + +It will be noticed that the Gnome motor is unusually +light, being about three pounds to the horse power +produced, as opposed to an average of 4 1/2 pounds per +horse power in other makes. This result is secured by +the elimination of the fly-wheel, the engine itself revolving, +thus obtaining the same effect that would be produced +by a fly-wheel. The Farcot is even lighter, being +considerably less than three pounds per horse power, +which is the nearest approach to the long-sought engine +equipment that will make possible a complete flying +machine the total weight of which will not exceed one +pound per square foot of area. + +How Lightness Is Secured. + +Thus far foreign manufacturers are ahead of Americans +in the production of light-weight aerial motors, as +is evidenced by the Gnome and Farcot engines, both of +which are of French make. Extreme lightness is made +possible by the use of fine, specially prepared steel for +the cylinders, thus permitting them to be much thinner +than if ordinary forms of steel were used. Another big +saving in weight is made by substituting what are +known as "auto lubricating" alloys for bearings. These +alloys are made of a combination of aluminum and magnesium. + +Still further gains are made in the use of alloy steel +tubing instead of solid rods, and also by the paring away +of material wherever it can be done without sacrificing +strength. This plan, with the exclusive use of the best +grades of steel, regardless of cost, makes possible a +marked reduction in weight. + +Multiplicity of Cylinders. + +Strange as it may seem, multiplicity of cylinders does +not always add proportionate weight. Because a 4- +cylinder motor weighs say 100 pounds, it does not necessarily +follow that an 8-cylinder equipment will weigh +200 pounds. The reason of this will be plain when it +is understood that many of the parts essential to a 4- +cylinder motor will fill the requirements of an 8-cylinder +motor without enlargement or addition. + +Neither does multiplying the cylinders always increase +the horsepower proportionately. If a 4-cylinder +motor is rated at 25 horsepower it is not safe to take +it for granted that double the number of cylinders will +give 50 horsepower. Generally speaking, eight cylinders, +the bore, stroke and speed being the same, will give +double the power that can be obtained from four, but +this does not always hold good. Just why this exception +should occur is not explainable by any accepted rule. + +Horse Power and Speed. + +Speed is an important requisite in a flying-machine +motor, as the velocity of the aeroplane is a vital factor +in flotation. At first thought, the propeller and similar +adjuncts being equal, the inexperienced mind would +naturally argue that a 50-horsepower engine should +produce just double the speed of one of 25-horsepower. +That this is a fallacy is shown by actual performances. +The Wrights, using a 25-horsepower motor, have made +44 miles an hour, while Bleriot, with a 50-horsepower +motor, has a record of a short-distance flight at the rate +of 52 miles an hour. The fact is that, so far as speed +is concerned, much depends upon the velocity of the +wind, the size and shape of the aeroplane itself, and the +size, shape and gearing of the propeller. The stronger +the wind is blowing the easier it will be for the aeroplane +to ascend, but at the same time the more difficult +it will be to make headway against the wind in a horizontal +direction. With a strong head wind, and proper +engine force, your machine will progress to a certain +extent, but it will be at an angle. If the aviator desired +to keep on going upward this would be all right, but +there is a limit to the altitude which it is desirable to +reach--from 100 to 500 feet for experts--and after that +it becomes a question of going straight ahead. + +Great Waste of Power. + +One thing is certain--even in the most efficient of +modern aerial motors there is a great loss of power between +the two points of production and effect. The +Wright outfit, which is admittedly one of the most effective +in use, takes one horsepower of force for the raising +and propulsion of each 50 pounds of weight. This, +for a 25-horsepower engine, would give a maximum lifting +capacity of 1250 pounds. It is doubtful if any of the +higher rated motors have greater efficiency. As an 8- +cylinder motor requires more fuel to operate than a 4- +cylinder, it naturally follows that it is more expensive +to run than the smaller motor, and a normal increase in +capacity, taking actual performances as a criterion, is +lacking. In other words, what is the sense of using an +8-cylinder motor when one of 4 cylinders is sufficient? + +What the Propeller Does. + +Much of the efficiency of the motor is due to the form +and gearing of the propeller. Here again, as in other +vital parts of flying-machine mechanism, we have a wide +divergence of opinion as to the best form. A fish makes +progress through the water by using its fins and tail; +a bird makes its way through the air in a similar manner +by the use of its wings and tail. In both instances the +motive power comes from the body of the fish or bird. + +In place of fins or wings the flying machine is equipped +with a propeller, the action of which is furnished by the +engine. Fins and wings have been tried, but they don't +work. + +While operating on the same general principle, aerial +propellers are much larger than those used on boats. +This is because the boat propeller has a denser, more +substantial medium to work in (water), and consequently +can get a better "hold," and produce more propulsive +force than one of the same size revolving in the air. +This necessitates the aerial propellers being much larger +than those employed for marine purposes. Up to this +point all aviators agree, but as to the best form most of +them differ. + +Kinds of Propellers Used. + +One of the most simple is that used by Curtiss. It +consists of two pear-shaped blades of laminated wood, +each blade being 5 inches wide at its extreme point, +tapering slightly to the shaft connection. These blades +are joined at the engine shaft, in a direct line. The propeller +has a pitch of 5 feet, and weighs, complete, less +than 10 pounds. The length from end to end of the two +blades is 6 1/2 feet. + +Wright uses two wooden propellers, in the rear of his +biplane, revolving in opposite directions. Each propeller +is two-bladed. + +Bleriot also uses a two-blade wooden propeller, but +it is placed in front of his machine. The blades are each +about 3 1/2 feet long and have an acute "twist." + +Santos-Dumont uses a two-blade wooden propeller, +strikingly similar to the Bleriot. + +On the Antoinette monoplane, with which good records +have been made, the propeller consists of two spoon- +shaped pieces of metal, joined at the engine shaft in +front, and with the concave surfaces facing the machine. + +The propeller on the Voisin biplane is also of metal, +consisting of two aluminum blades connected by a forged +steel arm. + +Maximum thrust, or stress--exercise of the greatest +air-displacing force--is the object sought. This, according +to experts, is best obtained with a large propeller +diameter and reasonably low speed. The diameter is the +distance from end to end of the blades, which on the +largest propellers ranges from 6 to 8 feet. The larger +the blade surface the greater will be the volume of air +displaced, and, following this, the greater will be the +impulse which forces the aeroplane ahead. In all centrifugal +motion there is more or less tendency to disintegration +in the form of "flying off" from the center, and +the larger the revolving object is the stronger is this +tendency. This is illustrated in the many instances in +which big grindstones and fly-wheels have burst from +being revolved too fast. To have a propeller break +apart in the air would jeopardize the life of the aviator, +and to guard against this it has been found best to make +its revolving action comparatively slow. Besides this +the slow motion (it is only comparatively slow) gives +the atmosphere a chance to refill the area disturbed by +one propeller blade, and thus have a new surface for +the next blade to act upon. + +Placing of the Motor. + +As on other points, aviators differ widely in their +ideas as to the proper position for the motor. Wright +locates his on the lower plane, midway between the front +and rear edges, but considerably to one side of the exact +center. He then counter-balances the engine weight by +placing his seat far enough away in the opposite direction +to preserve the center of gravity. This leaves a +space in the center between the motor and the operator +in which a passenger may be carried without disturbing +the equilibrium. + +Bleriot, on the contrary, has his motor directly in +front and preserves the center of gravity by taking his +seat well back, this, with the weight of the aeroplane, +acting as a counter-balance. + +On the Curtiss machine the motor is in the rear, the +forward seat of the operator, and weight of the horizontal +rudder and damping plane in front equalizing the +engine weight. + +No Perfect Motor as Yet. + +Engine makers in the United States, England, France +and Germany are all seeking to produce an ideal motor +for aviation purposes. Many of the productions are +highly creditable, but it may be truthfully said that +none of them quite fill the bill as regards a combination +of the minimum of weight with the maximum of +reliable maintained power. They are all, in some respects, +improvements upon those previously in use, but +the great end sought for has not been fully attained. + +One of the motors thus produced was made by the +French firm of Darracq at the suggestion of Santos Dumont, and on +lines laid down by him. Santos Dumont +wanted a 2-cylinder horizontal motor capable of developing +30 horsepower, and not exceeding 4 1/2 pounds per +horsepower in weight. + +There can be no question as to the ability and skill +of the Darracq people, or of their desire to produce a +motor that would bring new credit and prominence to +the firm. Neither could anything radically wrong be +detected in the plans. But the motor, in at least one +important requirement, fell short of expectations. + +It could not be depended upon to deliver an energy +of 30 horsepower continuously for any length of time. +Its maximum power could be secured only in "spurts." + +This tends to show how hard it is to produce an ideal +motor for aviation purposes. Santos Dumont, of undoubted +skill and experience as an aviator, outlined definitely +what he wanted; one of the greatest designers +in the business drew the plans, and the famous house of +Darracq bent its best energies to the production. But +the desired end was not fully attained. + +Features of Darracq Motor. + +Horizontal motors were practically abandoned some +time ago in favor of the vertical type, but Santos Dumont +had a logical reason for reverting to them. He +wanted to secure a lower center of gravity than would +be possible with a vertical engine. Theoretically his +idea was correct as the horizontal motor lies flat, and +therefore offers less resistance to the wind, but it did not +work out as desired. + +At the same time it must be admitted that this Darracq +motor is a marvel of ingenuity and exquisite workmanship. +The two cylinders, having a bore of 5 1-10 +inches and a stroke of 4 7-10 inches, are machined out +of a solid bar of steel until their weight is only 8 4-5 +pounds complete. The head is separate, carrying the +seatings for the inlet and exhaust valves, is screwed onto +the cylinder, and then welded in position. A copper +water-jacket is fitted, and it is in this condition that the +weight of 8 4-5 pounds is obtained. + +On long trips, especially in regions where gasolene is +hard to get, the weight of the fuel supply is an important +feature in aviation. As a natural consequence flying +machine operators favor the motor of greatest economy +in gasolene consumption, provided it gives the necessary +power. + +An American inventor, Ramsey by name, is working +on a motor which is said to possess great possibilities +in this line. Its distinctive features include a connecting +rod much shorter than usual, and a crank shaft located +the length of the crank from the central axis of the +cylinder. This has the effect of increasing the piston +stroke, and also of increasing the proportion of the +crank circle during which effective pressure is applied +to the crank. + +Making the connecting rod shorter and leaving the +crank mechanism the same would introduce excessive +cylinder friction. This Ramsey overcomes by the location +of his crank shaft. The effect of the long piston +stroke thus secured, is to increase the expansion of the +gases, which in turn increases the power of the engine +without increasing the amount of fuel used. + +Propeller Thrust Important. + +There is one great principle in flying machine propulsion +which must not be overlooked. No matter how +powerful the engine may be unless the propeller thrust +more than overcomes the wind pressure there can be +no progress forward. Should the force of this propeller +thrust and that of the wind pressure be equal the result +is obvious. The machine is at a stand-still so far +as forward progress is concerned and is deprived of the +essential advancing movement. + +Speed not only furnishes sustentation for the airship, +but adds to the stability of the machine. An aeroplane +which may be jerky and uncertain in its movements, so +far as equilibrium is concerned, when moving at a slow +gait, will readily maintain an even keel when the speed +is increased. + +Designs for Propeller Blades. + +It is the object of all men who design propellers to +obtain the maximum of thrust with the minimum expenditure +of engine energy. With this purpose in view +many peculiar forms of propeller blades have been +evolved. In theory it would seem that the best effects +could be secured with blades so shaped as to present a +thin (or cutting) edge when they come out of the wind, +and then at the climax of displacement afford a maximum +of surface so as to displace as much air as possible. +While this is the form most generally favored +there are others in successful operation. + +There is also wide difference in opinion as to the +equipment of the propeller shaft with two or more +blades. Some aviators use two and some four. All +have more or less success. As a mathematical proposition +it would seem that four blades should give more +propulsive force than two, but here again comes in one +of the puzzles of aviation, as this result is not always +obtained. + +Difference in Propeller Efficiency. + +That there is a great difference in propeller efficiency +is made readily apparent by the comparison of effects +produced in two leading makes of machines--the Wright +and the Voisin. + +In the former a weight of from 1,100 to 1,200 pounds +is sustained and advance progress made at the rate of +40 miles an hour and more, with half the engine speed +of a 25 horse-power motor. This would be a sustaining +capacity of 48 pounds per horsepower. But the actual +capacity of the Wright machine, as already stated, is 50 +pounds per horsepower. + +The Voisin machine, with aviator, weighs about 1,370 +pounds, and is operated with a so-horsepower motor. +Allowing it the same speed as the Wright we find that, +with double the engine energy, the lifting capacity is +only 27 1/2 pounds per horsepower. To what shall we +charge this remarkable difference? The surface of the +planes is exactly the same in both machines so there +is no advantage in the matter of supporting area. + +Comparison of Two Designs. + +On the Wright machine two wooden propellers of +two blades each (each blade having a decided "twist") +are used. As one 25 horsepower motor drives both propellers the +engine energy amounts to just one-half of +this for each, or 12 1/2 horsepower. And this energy is +utilized at one-half the normal engine speed. + +On the Voisin a radically different system is employed. +Here we have one metal two-bladed propeller with a +very slight "twist" to the blade surfaces. The full energy +of a 50-horsepower motor is utilized. + +Experts Fail to Agree. + +Why should there be such a marked difference in +the results obtained? Who knows? Some experts +maintain that it is because there are two propellers on +the Wright machine and only one on the Voisin, and +consequently double the propulsive power is exerted. +But this is not a fair deduction, unless both propellers +are of the same size. Propulsive power depends upon +the amount of air displaced, and the energy put into the +thrust which displaces the air. + +Other experts argue that the difference in results may +be traced to the difference in blade design, especially +in the matter of "twist." + +The fact is that propeller results depend largely upon +the nature of the aeroplanes on which they are used. +A propeller, for instance, which gives excellent results +on one type of aeroplane, will not work satisfactorily on +another. + +There are some features, however, which may be safely +adopted in propeller selection. These are: As extensive +a diameter as possible; blade area 10 to 15 per cent +of the area swept; pitch four-fifths of the diameter; +rotation slow. The maximum of thrust effort will be thus +obtained. + + + +CHAPTER X. + +PROPER DIMENSIONS OF MACHINES. + +In laying out plans for a flying machine the first thing +to decide upon is the size of the plane surfaces. The +proportions of these must be based upon the load to be +carried. This includes the total weight of the machine +and equipment, and also the operator. This will be a +rather difficult problem to figure out exactly, but +practical approximate figures may be reached. + +It is easy to get at the weight of the operator, motor +and propeller, but the matter of determining, before they +are constructed, what the planes, rudders, auxiliaries, +etc., will weigh when completed is an intricate proposition. +The best way is to take the dimensions of some +successful machine and use them, making such alterations +in a minor way as you may desire. + +Dimensions of Leading Machines. + +In the following tables will be found the details as to +surface area, weight, power, etc., of the nine principal +types of flying machines which are now prominently before +the public: + + MONOPLANES. + Surface area Spread in Depth in +Make Passengers sq. feet linear feet linear +feet +Santos-Dumont . . 1 110 16.0 26.0 +Bleriot . . . . . 1 150.6 24.6 22.0 +R. E. P . . . . . 1 215 34.1 28.9 +Bleriot . . . . . 2 236 32.9 23.0 +Antoinette. . . . 2 538 41.2 37.9 + No. of Weight Without +Propeller +Make Cylinders Horse Power Operator +Diameter +Santos-Dumont. . 2 30 250 5.0 +Bleriot. . . . . 3 25 680 6.9 +R. E. P. . . . . 7 35 900 6.6 +Bleriot. . . . . 7 50 1,240 8.1 +Antoinette . . . 8 50 1,040 7.2 + + BIPLANES. + Surface Area Spread in Depth +in +Make Passengers sq. feet linear feet linear +feet +Curtiss . . . 2 258 29.0 +28.7 +Wright. . . . 2 538 41.0 +30.7 +Farman. . . . 2 430 32.9 +39.6 +Voisin. . . . 2 538 37.9 +39.6 + + No. of Weight Without +Propeller +Make Cylinders Horse Power Operator +Diameter +Curtiss . . . 8 50 600 6.0 +Wright. . . . 4 25 1,100 8.1 +Farman. . . . 7 50 1,200 8.9 +Voisin. . . . 8 50 1,200 6.6 + +In giving the depth dimensions the length over all-- +from the extreme edge of the front auxiliary plane to +the extreme tip of the rear is stated. Thus while the +dimensions of the main planes of the Wright machine +are 41 feet spread by 6 1/2 feet in depth, the depth over +all is 30.7. + +Figuring Out the Details. + +With this data as a guide it should be comparatively +easy to decide upon the dimensions of the machine required. +In arriving at the maximum lifting capacity the +weight of the operator must be added. Assuming this +to average 170 pounds the method of procedure would be +as follows: + +Add the weight of the operator to the weight of the +complete machine. The new Wright machine complete +weighs 900 pounds. This, plus 170, the weight of the +operator, gives a total of 1,070 pounds. There are 538 +square feet of supporting surface, or practically one +square foot of surface area to each two pounds of load. + +There are some machines, notably the Bleriot, in which +the supporting power is much greater. In this latter +instance we find a surface area of 150 1/2 square feet +carrying a load of 680 plus 170, or an aggregate of 850 +pounds. This is the equivalent of five pounds to the +square foot. This ratio is phenomenally large, and +should not be taken as a guide by amateurs. + +The Matter of Passengers. + +These deductions are based on each machine carrying +one passenger, which is admittedly the limit at present +of the monoplanes like those operated for record-making +purposes by Santos-Dumont and Bleriot. The biplanes, +however, have a two-passenger capacity, and this adds +materially to the proportion of their weight-sustaining +power as compared with the surface area. In the following +statement all the machines are figured on the +one-passenger basis. Curtiss and Wright have carried +two passengers on numerous occasions, and an extra 170 +pounds should therefore be added to the total weight +carried, which would materially increase the capacity. +Even with the two-passenger load the limit is by no +means reached, but as experiments have gone no further +it is impossible to make more accurate figures. + +Average Proportions of Load. + +It will be interesting, before proceeding to lay out the +dimension details, to make a comparison of the proportion +of load effect with the supporting surfaces of various +well-known machines. Here are the figures: + +Santos-Dumont--A trifle under four pounds per square +foot. + +Bleriot--Five pounds. + +R. E. P.--Five pounds. + +Antoinette--About two and one-quarter pounds. + +Curtiss--About two and one-half pounds. + +Wright--Two and one-quarter pounds. + +Farman--A trifle over three pounds. + +Voisin--A little under two and one-half pounds. + +Importance of Engine Power. + +While these figures are authentic, they are in a way +misleading, as the important factor of engine power +is not taken into consideration. Let us recall the fact +that it is the engine power which keeps the machine in +motion, and that it is only while in motion that the machine +will remain suspended in the air. Hence, to attribute the support +solely to the surface area is erroneous. +True, that once under headway the planes contribute +largely to the sustaining effect, and are absolutely essential +in aerial navigation--the motor could not rise without +them--still, when it comes to a question of weight- +sustaining power, we must also figure on the engine +capacity. + +In the Wright machine, in which there is a lifting +capacity of approximately 2 1/4 pounds to the square foot +of surface area, an engine of only 25 horsepower is used. +In the Curtiss, which has a lifting capacity of 2 1/2 +pounds per square foot, the engine is of 50 horsepower. +This is another of the peculiarities of aerial construction +and navigation. Here we have a gain of 1/4 pound in +weight-lifting capacity with an expenditure of double +the horsepower. It is this feature which enables Curtiss +to get along with a smaller surface area of supporting +planes at the expense of a big increase in engine power. +Proper Weight of Machine. + +As a general proposition the most satisfactory machine +for amateur purposes will be found to be one with +a total weight-sustaining power of about 1,200 pounds. +Deducting 170 pounds as the weight of the operator, +this will leave 1,030 pounds for the complete motor- +equipped machine, and it should be easy to construct one +within this limit. This implies, of course, that due care +will be taken to eliminate all superfluous weight by using +the lightest material compatible with strength and safety. + +This plan will admit of 686 pounds weight in the +frame work, coverings, etc., and 344 for the motor, +propeller, etc., which will be ample. Just how to distribute +the weight of the planes is a matter which must +be left to the ingenuity of the builder. + +Comparison of Bird Power. + +There is an interesting study in the accompanying +illustration. Note that the surface area of the albatross +is much smaller than that of the vulture, although the +wing spread is about the same. Despite this the albatross +accomplishes fully as much in the way of flight +and soaring as the vulture. Why? Because the albaboss is quicker +and more powerful in action. It is +the application of this same principle in flying machines +which enables those of great speed and power to get +along with less supporting surface than those of slower +movement. + +Measurements of Curtiss Machine. + +Some idea of framework proportion may be had from +the following description of the Curtiss machine. The +main planes have a spread (width) of 29 feet, and are +4 1/2 feet deep. The front double surface horizontal rudder +is 6x2 feet, with an area of 24 square feet. To the +rear of the main planes is a single surface horizontal +plane 6x2 feet, with an area of 12 square feet. In connection +with this is a vertical rudder 2 1/2 feet square. +Two movable ailerons, or balancing planes, are placed +at the extreme ends of the upper planes. These are 6x2 +feet, and have a combined area of 24 square feet. There +is also a triangular shaped vertical steadying surface in +connection with the front rudder. + +Thus we have a total of 195 square feet, but as the +official figures are 258, and the size of the triangular- +shaped steadying surface is unknown, we must take it +for granted that this makes up the difference. In the +matter of proportion the horizontal double-plane rudder +is about one-tenth the size of the main plane, counting +the surface area of only one plane, the vertical rudder +one-fortieth, and the ailerons one-twentieth. + + + +CHAPTER XI. + +PLANE AND RUDDER CONTROL. + +Having constructed and equipped your machine, the +next thing is to decide upon the method of controlling +the various rudders and auxiliary planes by which the +direction and equilibrium and ascending and descending +of the machine are governed. + +The operator must be in position to shift instantaneously the +position of rudders and planes, and also to control +the action of the motor. This latter is supposed to +work automatically and as a general thing does so with +entire satisfaction, but there are times when the supply +of gasolene must be regulated, and similar things done. +Airship navigation calls for quick action, and for this +reason the matter of control is an important one--it is +more than important; it is vital. + +Several Methods of Control. + +Some aviators use a steering wheel somewhat after +the style of that used in automobiles, and by this not +only manipulate the rudder planes, but also the flow of +gasolene. Others employ foot levers, and still others, +like the Wrights, depend upon hand levers. + +Curtiss steers his aeroplane by means of a wheel, but +secures the desired stabilizing effect with an ingenious +jointed chair-back. This is so arranged that by leaning +toward the high point of his wing planes the aeroplane +is restored to an even keel. The steering post of the +wheel is movable backward and forward, and by this +motion elevation is obtained. + +The Wrights for some time used two hand levers, one +to steer by and warp the flexible tips of the planes, the +other to secure elevation. They have now consolidated +all the functions in one lever. Bleriot also uses the +single lever control. + +Farman employs a lever to actuate the rudders, but +manipulates the balancing planes by foot levers. + +Santos-Dumont uses two hand levers with which to +steer and elevate, but manipulates the planes by means +of an attachment to the back of his outer coat. + +Connection With the Levers. + +No matter which particular method is employed, the +connection between the levers and the object to be manipulated +is almost invariably by wire. For instance, from +the steering levers (or lever) two wires connect with opposite +sides of the rudder. As a lever is moved so as to +draw in the right-hand wire the rudder is drawn to the +right and vice versa. The operation is exactly the same +as in steering a boat. It is the same way in changing +the position of the balancing planes. A movement of +the hands or feet and the machine has changed its +course, or, if the equilibrium is threatened, is back on +an even keel. + +Simple as this seems it calls for a cool head, quick +eye, and steady hand. The least hesitation or a false +movement, and both aviator and craft are in danger. + +Which Method is Best? + +It would be a bold man who would attempt to pick +out any one of these methods of control and say it was +better than the others. As in other sections of aeroplane +mechanism each method has its advocates who dwell +learnedly upon its advantages, but the fact remains that +all the various plans work well and give satisfaction. + +What the novice is interested in knowing is how the +control is effected, and whether he has become proficient +enough in his manipulation of it to be absolutely dependable +in time of emergency. No amateur should attempt +a flight alone, until he has thoroughly mastered +the steering and plane control. If the services and advice of an +experienced aviator are not to be had the +novice should mount his machine on some suitable supports +so it will be well clear of the ground, and, getting +into the operator's seat, proceed to make himself well +acquainted with the operation of the steering wheel and +levers. + +Some Things to Be Learned. + +He will soon learn that certain movements of the +steering gear produce certain effects on the rudders. If, +for instance, his machine is equipped with a steering +wheel, he will find that turning the wheel to the right +turns the aeroplane in the same direction, because the +tiller is brought around to the left. In the same way +he will learn that a given movement of the lever throws +the forward edge of the main plane upward, and that the +machine, getting the impetus of the wind under the concave +surfaces of the planes, will ascend. In the same +way it will quickly become apparent to him that an opposite +movement of the lever will produce an opposite +effect--the forward edges of the planes will be lowered, +the air will be "spilled" out to the rear, and the machine +will descend. + +The time expended in these preliminary lessons will +be well spent. It would be an act of folly to attempt to +actually sail the craft without them. + + + +CHAPTER XII. + +HOW TO USE THE MACHINE. + +It is a mistaken idea that flying machines must be +operated at extreme altitudes. True, under the impetus +of handsome prizes, and the incentive to advance scientific +knowledge, professional aviators have ascended to +considerable heights, flights at from 500 to 1,500 feet being +now common with such experts as Farman, Bleriot, +Latham, Paulhan, Wright and Curtiss. The altitude +record at this time is about 4,165 feet, held by Paulhan. + +One of the instructions given by experienced aviators +to pupils, and for which they insist upon implicit obeyance, is: +"If your machine gets more than 30 feet high, +or comes closer to the ground than 6 feet, descend at +once." Such men as Wright and Curtiss will not tolerate +a violation of this rule. If their instructions are +not strictly complied with they decline to give the offender +further lessons. + +Why This Rule Prevails. + +There is good reason for this precaution. The higher +the altitude the more rarefied (thinner) becomes the air, +and the less sustaining power it has. Consequently the +more difficult it becomes to keep in suspension a given +weight. When sailing within 30 feet of the ground sustentation +is comparatively easy and, should a fall occur, +the results are not likely to be serious. On the other +hand, sailing too near the ground is almost as objectionable +in many ways as getting up too high. If the craft +is navigated too close to the ground trees, shrubs, fences +and other obstructions are liable to be encountered. +There is also the handicap of contrary air currents +diverted by the obstructions referred to, and which will +be explained more fully further on. + +How to Make a Start. + +Taking it for granted that the beginner has familiarized +himself with the manipulation of the machine, and especially +the control mechanism, the next thing in order +is an actual flight. It is probable that his machine will +be equipped with a wheeled alighting gear, as the skids +used by the Wrights necessitate the use of a special +starting track. In this respect the wheeled machine is +much easier to handle so far as novices are concerned +as it may be easily rolled to the trial grounds. This, +as in the case of the initial experiments, should be a +clear, reasonably level place, free from trees, fences, +rocks and similar obstructions with which there may be +danger of colliding. + +The beginner will need the assistance of three men. +One of these should take his position in the rear of the +machine, and one at each end. On reaching the trial +ground the aviator takes his seat in the machine and, +while the men at the ends hold it steady the one in the rear +assists in retaining it until the operator is ready. In the +meantime the aviator has started his motor. Like the +glider the flying machine, in order to accomplish the +desired results, should be headed into the wind. + +When the Machine Rises. + +Under the impulse of the pushing movement, and assisted +by the motor action, the machine will gradually +rise from the ground--provided it has been properly +proportioned and put together, and everything is in working +order. This is the time when the aviator requires +a cool head, At a modest distance from the ground use +the control lever to bring the machine on a horizontal +level and overcome the tendency to rise. The exact +manipulation of this lever depends upon the method of +control adopted, and with this the aviator is supposed +to have thoroughly familiarized himself as previously +advised in Chapter XI. + +It is at this juncture that the operator must act +promptly, but with the perfect composure begotten of +confidence. One of the great drawbacks in aviation by +novices is the tendency to become rattled, and this is +much more prevalent than one might suppose, even +among men who, under other conditions, are cool and +confident in their actions. + +There is something in the sensation of being suddenly +lifted from the ground, and suspended in the air that is +disconcerting at the start, but this will soon wear off if +the experimenter will keep cool. A few successful flights +no matter how short they may be, will put a lot of +confidence into him. + +Make Your Flights Short. + +Be modest in your initial flights. Don't attempt to +match the records of experienced men who have devoted +years to mastering the details of aviation. Paulhan, +Farman, Bleriot, Wright, Curtiss, and all the rest of +them began, and practiced for years, in the manner here +described, being content to make just a little advancement +at each attempt. A flight of 150 feet, cleanly and +safely made, is better as a beginning than one of 400 +yards full of bungling mishaps. + +And yet these latter have their uses, provided the +operator is of a discerning mind and can take advantage +of them as object lessons. But, it is not well to invite +them. They will occur frequently enough under the +most favorable conditions, and it is best to have them +come later when the feeling of trepidation and uncertainty +as to what to do has worn off. + +Above all, don't attempt to fly too high. Keep within +a reasonable distance from the ground--about 25 or 30 +feet. This advice is not given solely to lessen the risk +of serious accident in case of collapse, but mainly because +it will assist to instill confidence in the operator. + +It is comparatively easy to learn to swim in shallow +water, but the knowledge that one is tempting death in +deep water begets timidity. + +Preserving the Equilibrium. + +After learning how to start and stop, to ascend and +descend, the next thing to master is the art of preserving +equilibrium, the knack of keeping the machine perfectly +level in the air--on an "even keel," as a sailor would +say. This simile is particularly appropriate as all aviators +are in reality sailors, and much more daring ones +than those who course the seas. The latter are in craft +which are kept afloat by the buoyancy of the water, +whether in motion or otherwise and, so long as normal +conditions prevail, will not sink. Aviators sail the air +in craft in which constant motion must be maintained in +order to ensure flotation. + +The man who has ridden a bicycle or motorcycle +around curves at anything like high speed, will have a +very good idea as to the principle of maintaining equilibrium +in an airship. He knows that in rounding curves +rapidly there is a marked tendency to change the direction +of the motion which will result in an upset unless +he overcomes it by an inclination of his body in an opposite +direction. This is why we see racers lean well +over when taking the curves. It simply must be done +to preserve the equilibrium and avoid a spill. + +How It Works In the Air. + +If the equilibrium of an airship is disturbed to an +extent which completely overcomes the center of gravity +it falls according to the location of the displacement. +If this displacement, for instance, is at either end the +apparatus falls endways; if it is to the front or rear, the +fall is in the corresponding direction. + +Owing to uncertain air currents--the air is continually +shifting and eddying, especially within a hundred feet or +so of the earth--the equilibrium of an airship is almost +constantly being disturbed to some extent. Even if this +disturbance is not serious enough to bring on a fall it +interferes with the progress of the machine, and should +be overcome at once. This is one of the things connected +with aerial navigation which calls for prompt, +intelligent action. + +Frequently, when the displacement is very slight, it +may be overcome, and the craft immediately righted by +a mere shifting of the operator's body. Take, for illustration, +a case in which the extreme right end of the +machine becomes lowered a trifle from the normal level. +It is possible to bring it back into proper position by +leaning over to the left far enough to shift the weight +to the counter-balancing point. The same holds good as +to minor front or rear displacements. + +When Planes Must Be Used. + +There are other displacements, however, and these are +the most frequent, which can be only overcome by manipulation of +the stabilizing planes. The method of procedure +depends upon the form of machine in use. The +Wright machine, as previously explained, is equipped +with plane ends which are so contrived as to admit of +their being warped (position changed) by means of the +lever control. These flexible tip planes move simultaneously, +but in opposite directions. As those on one end +rise, those on the other end fall below the level of the +main plane. By this means air is displaced at one point, +and an increased amount secured in another. + +This may seem like a complicated system, but its +workings are simple when once understood. It is by +the manipulation or warping of these flexible tips that +transverse stability is maintained, and any tendency to +displacement endways is overcome. Longitudinal stability +is governed by means of the front rudder. + +Stabilizing planes of some form are a feature, and a +necessary feature, on all flying machines, but the methods +of application and manipulation vary according to the +individual ideas of the inventors. They all tend, however, +toward the same end--the keeping of the machine +perfectly level when being navigated in the air. + +When to Make a Flight. + +A beginner should never attempt to make a flight +when a strong wind is blowing. The fiercer the wind, +the more likely it is to be gusty and uncertain, and the +more difficult it will be to control the machine. Even +the most experienced and daring of aviators find there +is a limit to wind speed against which they dare not +compete. This is not because they lack courage, but +have the sense to realize that it would be silly and useless. + +The novice will find a comparatively still day, or one +when the wind is blowing at not to exceed 15 miles an +hour, the best for his experiments. The machine will be +more easily controlled, the trip will be safer, and also +cheaper as the consumption of fuel increases with the +speed of the wind against which the aeroplane is forced. + + + +CHAPTER XIII. + +PECULIARITIES OF AIRSHIP POWER. + +As a general proposition it takes much more power to +propel an airship a given number of miles in a certain +time than it does an automobile carrying a far heavier +load. Automobiles with a gross load of 4,000 pounds, +and equipped with engines of 30 horsepower, have travelled +considerable distances at the rate of 50 miles an +hour. This is an equivalent of about 134 pounds per +horsepower. For an average modern flying machine, +with a total load, machine and passengers, of 1,200 +pounds, and equipped with a 50-horsepower engine, 50 +miles an hour is the maximum. Here we have the equivalent +of exactly 24 pounds per horsepower. Why this +great difference? + +No less an authority than Mr. Octave Chanute answers +the question in a plain, easily understood manner. He +says: + +"In the case of an automobile the ground furnishes a +stable support; in the case of a flying machine the engine +must furnish the support and also velocity by which the +apparatus is sustained in the air." + +Pressure of the Wind. + +Air pressure is a big factor in the matter of aeroplane +horsepower. Allowing that a dead calm exists, a body +moving in the atmosphere creates more or less resistance. +The faster it moves, the greater is this resistance. +Moving at the rate of 60 miles an hour the resistance, +or wind pressure, is approximately 50 pounds to the +square foot of surface presented. If the moving object +is advancing at a right angle to the wind the following +table will give the horsepower effect of the resistance +per square foot of surface at various speeds. + + Horse Power +Miles per Hour per sq. foot +10 0.013 +15 0 044 +20 0.105 +25 0.205 +30 0.354 +40 0.84 +50 1.64 +60 2.83 +80 6.72 +100 13.12 + +While the pressure per square foot at 60 miles an hour, +is only 1.64 horsepower, at 100 miles, less than double +the speed, it has increased to 13.12 horsepower, or exactly +eight times as much. In other words the pressure +of the wind increases with the square of the velocity. +Wind at 10 miles an hour has four times more pressure +than wind at 5 miles an hour. + +How to Determine Upon Power. + +This element of air resistance must be taken into consideration +in determining the engine horsepower required. +When the machine is under headway sufficient +to raise it from the ground (about 20 miles an hour), +each square foot of surface resistance, will require nearly +nine-tenths of a horsepower to overcome the wind pressure, +and propel the machine through the air. As +shown in the table the ratio of power required increases +rapidly as the speed increases until at 60 miles an hour +approximately 3 horsepower is needed. + +In a machine like the Curtiss the area of wind-exposed +surface is about 15 square feet. On the basis of this +resistance moving the machine at 40 miles an hour would +require 12 horsepower. This computation covers only +the machine's power to overcome resistance. It does +not cover the power exerted in propelling the machine +forward after the air pressure is overcome. To meet +this important requirement Mr. Curtiss finds it necessary +to use a 50-horsepower engine. Of this power, as +has been already stated, 12 horsepower is consumed +in meeting the wind pressure, leaving 38 horsepower +for the purpose of making progress. + +The flying machine must move faster than the air to +which it is opposed. Unless it does this there can be no +direct progress. If the two forces are equal there is no +straight-ahead advancement. Take, for sake of illustration, +a case in which an aeroplane, which has developed a +speed of 30 miles an hour, meets a wind velocity of +equal force moving in an opposite direction. What is +the result? There can be no advance because it is a +contest between two evenly matched forces. The aeroplane +stands still. The only way to get out of the difficulty +is for the operator to wait for more favorable conditions, +or bring his machine to the ground in the usual +manner by manipulation of the control system. + +Take another case. An aeroplane, capable of making +50 miles an hour in a calm, is met by a head wind of 25 +miles an hour. How much progress does the aeroplane +make? Obviously it is 25 miles an hour over the ground. + +Put the proposition in still another way. If the wind +is blowing harder than it is possible for the engine power +to overcome, the machine will be forced backward. + +Wind Pressure a Necessity. + +While all this is true, the fact remains that wind +pressure, up to a certain stage, is an absolute necessity +in aerial navigation. The atmosphere itself has very +little real supporting power, especially if inactive. If +a body heavier than air is to remain afloat it must move +rapidly while in suspension. + +One of the best illustrations of this is to be found in +skating over thin ice. Every school boy knows that if +he moves with speed he may skate or glide in safety +across a thin sheet of ice that would not begin to bear +his weight if he were standing still. Exactly the same +proposition obtains in the case of the flying machine. + +The non-technical reason why the support of the machine +becomes easier as the speed increases is that the +sustaining power of the atmosphere increases with the +resistance, and the speed with which the object is moving +increases this resistance. With a velocity of 12 miles +an hour the weight of the machine is practically reduced +by 230 pounds. Thus, if under a condition of absolute +calm it were possible to sustain a weight of 770 pounds, +the same atmosphere would sustain a weight of 1,000 +pounds moving at a speed of 12 miles an hour. This +sustaining power increases rapidly as the speed increases. +While at 12 miles the sustaining power is figured at +230 pounds, at 24 miles it is four times as great, or 920 +pounds. + +Supporting Area of Birds. + +One of the things which all producing aviators seek +to copy is the motive power of birds, particularly in their +relation to the area of support. Close investigation has +established the fact that the larger the bird the less is +the relative area of support required to secure a given +result. This is shown in the following table: + + Supporting + Weight Surface Horse area +Bird in lbs. in sq. feet power per lb. +Pigeon 1.00 0.7 0.012 0.7 +Wild Goose 9.00 2.65 0.026 0.2833 +Buzzard 5.00 5.03 0.015 1.06 +Condor 17.00 9.85 0.043 0.57 + +So far as known the condor is the largest of modern +birds. It has a wing stretch of 10 feet from tip to tip, a +supporting area of about 10 square feet, and weighs 17 +pounds. It. is capable of exerting perhaps 1-30 horsepower. +(These figures are, of course, approximate.) +Comparing the condor with the buzzard with a wing +stretch of 6 feet, supporting area of 5 square feet, and a +little over 1-100 horsepower, it may be seen that, broadly +speaking, the larger the bird the less surface area (relatively) +is needed for its support in the air. + +Comparison With Aeroplanes. + +If we compare the bird figures with those made possible +by the development of the aeroplane it will be +readily seen that man has made a wonderful advance in +imitating the results produced by nature. Here are the +figures: + + Supporting + Weight Surface Horse area +Machine in lbs. in sq. feet power per lb. +Santos-Dumont . . 350 110.00 30 0.314 +Bleriot . . . . . 700 150.00 25 0.214 +Antoinette. . . . 1,200 538.00 50 0.448 +Curtiss . . . . . 700 258.00 60 0.368 +Wright. . . . .[4]1,100 538.00 25 0.489 +Farman. . . . . . 1,200 430.00 50 0.358 +Voisin. . . . . . 1,200 538.00 50 0.448 + +[4] The Wrights' new machine weighs only 900 pounds. + +While the average supporting surface is in favor of +the aeroplane, this is more than overbalanced by the +greater amount of horsepower required for the weight +lifted. The average supporting surface in birds is about +three-quarters of a square foot per pound. In the average +aeroplane it is about one-half square foot per pound. +On the other hand the average aeroplane has a lifting +capacity of 24 pounds per horsepower, while the buzzard, +for instance, lifts 5 pounds with 15-100 of a horsepower. +If the Wright machine--which has a lifting power of 50 +pounds per horsepower--should be alone considered the +showing would be much more favorable to the aeroplane, +but it would not be a fair comparison. + +More Surface, Less Power. + +Broadly speaking, the larger the supporting area the +less will be the power required. Wright, by the use of +538 square feet of supporting surface, gets along with an +engine of 25 horsepower. Curtiss, who uses only 258 +square feet of surface, finds an engine of 50 horsepower +is needed. Other things, such as frame, etc., being equal, +it stands to reason that a reduction in the area of +supporting surface will correspondingly reduce the weight +of the machine. Thus we have the Curtiss machine with +its 258 square feet of surface, weighing only 600 pounds +(without operator), but requiring double the horsepower +of the Wright machine with 538 square feet of surface +and weighing 1,100 pounds. This demonstrates in a +forceful way the proposition that the larger the surface +the less power will be needed. + +But there is a limit, on account of its bulk and +awkwardness in handling, beyond which the surface area +cannot be enlarged. Otherwise it might be possible to +equip and operate aeroplanes satisfactorily with engines +of 15 horsepower, or even less. + +The Fuel Consumption Problem. + +Fuel consumption is a prime factor in the production +of engine power. The veriest mechanical tyro knows in +a general way that the more power is secured the more +fuel must be consumed, allowing that there is no difference +in the power-producing qualities of the material +used. But few of us understand just what the ratio of +increase is, or how it is caused. This proposition is one +of keen interest in connection with aviation. + +Let us cite a problem which will illustrate the point +quoted: Allowing that it takes a given amount of gasolene +to propel a flying machine a given distance, half the +way with the wind, and half against it, the wind blowing +at one-half the speed of the machine, what will be +the increase in fuel consumption? + +Increase of Thirty Per Cent. + +On the face of it there would seem to be no call for +an increase as the resistance met when going against the +wind is apparently offset by the propulsive force of the +wind when the machine is travelling with it. This, however, +is called faulty reasoning. The increase in fuel +consumption, as figured by Mr. F. W. Lanchester, of the +Royal Society of Arts, will be fully 30 per cent over +the amount required for a similar operation of the machine +in still air. If the journey should be made at right +angles to the wind under the same conditions the increase +would be 15 per cent. + +In other words Mr. Lanchester maintains that the work +done by the motor in making headway against the wind +for a certain distance calls for more engine energy, and +consequently more fuel by 30 per cent, than is saved by +the helping force of the wind on the return journey. + + + +CHAPTER XIV. + +ABOUT WIND CURRENTS, ETC. + +One of the first difficulties which the novice will +encounter is the uncertainty of the wind currents. With a +low velocity the wind, some distance away from the +ground, is ordinarily steady. As the velocity increases, +however, the wind generally becomes gusty and fitful +in its action. This, it should be remembered, does not +refer to the velocity of the machine, but to that of the +air itself. + +In this connection Mr. Arthur T. Atherholt, president +of the Aero Club of Pennsylvania, in addressing the +Boston Society of Scientific Research, said: + +"Probably the whirlpools of Niagara contain no more +erratic currents than the strata of air which is now immediately +above us, a fact hard to realize on account +of its invisibility." + +Changes In Wind Currents. + +While Mr. Atherholt's experience has been mainly +with balloons it is all the more valuable on this account, +as the balloons were at the mercy of the wind and their +varying directions afforded an indisputable guide as to +the changing course of the air currents. In speaking of +this he said: + +"In the many trips taken, varying in distance traversed +from twenty-five to 900 miles, it was never possible +except in one instance to maintain a straight course. +These uncertain currents were most noticeable in the +Gordon-Bennett race from St. Louis in 1907. Of the +nine aerostats competing in that event, eight covered a +more or less direct course due east and southeast, whereas +the writer, with Major Henry B. Hersey, first started +northwest, then north, northeast, east, east by south, and +when over the center of Lake Erie were again blown +northwest notwithstanding that more favorable winds +were sought for at altitudes varying from 100 to 3,000 +meters, necessitating a finish in Canada nearly northeast +of the starting point. + +"These nine balloons, making landings extending from +Lake Ontario, Canada, to Virginia, all started from one +point within the same hour. + +"The single exception to these roving currents occurred +on October 21st, of last year (1909) when, starting +from Philadelphia, the wind shifted more than eight +degrees, the greatest variation being at the lowest altitudes, +yet at no time was a height of over a mile reached. + +"Throughout the entire day the sky was overcast, with +a thermometer varying from fifty-seven degrees at 300 +feet to forty-four degrees, Fahrenheit at 5,000 feet, at +which altitude the wind had a velocity of 43 miles an +hour, in clouds of a cirro-cumulus nature, a landing finally +being made near Tannersville, New York, in the +Catskill mountains, after a voyage of five and one-half +hours. + +"I have no knowledge of a recorded trip of this distance +and duration, maintained in practically a straight +line from start to finish." + +This wind disturbance is more noticeable and more +difficult to contend with in a balloon than in a flying +machine, owing to the bulk and unwieldy character of +the former. At the same time it is not conducive to +pleasant, safe or satisfactory sky-sailing in an aeroplane. +This is not stated with the purpose of discouraging +aviation, but merely that the operator may know what to +expect and be prepared to meet it. + +Not only does the wind change its horizontal course +abruptly and without notice, but it also shifts in a vertical +direction, one second blowing up, and another +down. No man has as yet fathomed the why and wherefore +of this erratic action; it is only known that it exists. + +The most stable currents will be found from 50 to 100 +feet from the earth, provided the wind is not diverted +by such objects as trees, rocks, etc. That there are +equally stable currents higher up is true, but they are +generally to be found at excessive altitudes. + +How a Bird Meets Currents. + +Observe a bird in action on a windy day and you will +find it continually changing the position of its wings. +This is done to meet the varying gusts and eddies of the +air so that sustentation may be maintained and headway +made. One second the bird is bending its wings, altering +the angle of incidence; the next it is lifting or depressing +one wing at a time. Still again it will extend +one wing tip in advance of the other, or be spreading or +folding, lowering or raising its tail. + +All these motions have a meaning, a purpose. They +assist the bird in preserving its equilibrium. Without +them the bird would be just as helpless in the air as a +human being and could not remain afloat. + +When the wind is still, or comparatively so, a bird, +having secured the desired altitude by flight at an angle, +may sail or soar with no wing action beyond an occasional +stroke when it desires to advance. But, in a +gusty, uncertain wind it must use its wings or alight +somewhere. + +Trying to Imitate the Bird. + +Writing in _Fly_, Mr. William E. White says: + +"The bird's flight suggests a number of ways in which +the equilibrium of a mechanical bird may be controlled. +Each of these methods of control may be effected by +several different forms of mechanism. + +"Placing the two wings of an aeroplane at an angle of +three to five degrees to each other is perhaps the oldest +way of securing lateral balance. This way readily occurs +to anyone who watches a sea gull soaring. The +theory of the dihedral angle is that when one wing is +lifted by a gust of wind, the air is spilled from under it; +while the other wing, being correspondingly depressed, +presents a greater resistance to the gust and is lifted +restoring the balance. A fixed angle of three to five degrees, +however, will only be sufficient for very light puffs +of wind and to mount the wings so that the whole wing +may be moved to change the dihedral angle presents +mechanical difficulties which would be better avoided. + +"The objection of mechanical impracticability applies +to any plan to preserve the balance by shifting weight +or ballast. The center of gravity should be lower than +the center of the supporting surfaces, but cannot be +made much lower. It is a common mistake to assume +that complete stability will be secured by hanging the +center of gravity very low on the principle of the +parachute. An aeroplane depends upon rapid horizontal motion for +its support, and if the center of gravity be far +below the center of support, every change of speed or +wind pressure will cause the machine to turn about its +center of gravity, pitching forward and backward dangerously. + +Preserving Longitudinal Balance. + +"The birds maintain longitudinal, or fore and aft balance, +by elevating or depressing their tails. Whether +this action is secured in an aeroplane by means of a +horizontal rudder placed in the rear, or by deflecting +planes placed in front of the main planes, the principle +is evidently the same. A horizontal rudder placed well +to the rear as in the Antoinette, Bleriot or Santos-Dumont +monoplanes, will be very much safer and steadier +than the deflecting planes in front, as in the Wright or +Curtiss biplanes, but not so sensitive or prompt in action. + +"The natural fore and aft stability is very much +strengthened by placing the load well forward. The +center of gravity near the front and a tail or rudder +streaming to the rear secures stability as an arrow is +balanced by the head and feathering. The adoption of +this principle makes it almost impossible for the aeroplane +to turn over. + +The Matter of Lateral Balance. + +"All successful aeroplanes thus far have maintained +lateral balance by the principle of changing the angle +of incidence of the wings. + +"Other ways of maintaining the lateral balance, suggested +by observation of the flight of birds are--extending +the wing tips and spilling the air through the pinions; +or, what is the same thing, varying the area of the +wings at their extremities. + +"Extending the wing tips seems to be a simple and +effective solution of the problem. The tips may be made +to swing outward upon a vertical axis placed at the front +edge of the main planes; or they may be hinged to the +ends of the main plane so as to be elevated or depressed +through suitable connections by the aviator; or they may +be supported from a horizontal axis parallel with the +ends of the main planes so that they may swing outward, +the aviator controlling both tips through one lever +so that as one tip is extended the other is retracted. + +"The elastic wing pinions of a bird bend easily before +the wind, permitting the gusts to glance off, but presenting +always an even and efficient curvature to the +steady currents of the air." + +High Winds Threaten Stability. + +To ensure perfect stability, without control, either human +or automatic, it is asserted that the aeroplane must +move faster than the wind is blowing. So long as the +wind is blowing at the rate of 30 miles an hour, and the +machine is traveling 40 or more, there will be little trouble +as regards equilibrium so far as wind disturbance +goes, provided the wind blows evenly and does not come +in gusts or eddying currents. But when conditions are +reversed--when the machine travels only 30 miles an +hour and the wind blows at the rate of 50, look out for +loss of equilibrium. + +One of the main reasons for this is that high winds +are rarely steady; they seldom blow for any length of +time at the same speed. They are usually "gusty," the +gusts being a momentary movement at a higher speed. +Tornadic gusts are also formed by the meeting of two +opposing currents, causing a whirling motion, which +makes stability uncertain. Besides, it is not unusual +for wind of high speed to suddenly change its direction +without warning. + +Trouble With Vertical Columns. + +Vertical currents--columns of ascending air--are +frequently encountered in unexpected places and have more +or less tendency, according to their strength, to make +it difficult to keep the machine within a reasonable +distance from the ground. + +These vertical currents are most generally noticeable +in the vicinity of steep cliffs, or deep ravines. In such +instances they are usually of considerable strength, being +caused by the deflection of strong winds blowing +against the face of the cliffs. This deflection exerts a +back pressure which is felt quite a distance away from +the point of origin, so that the vertical current exerts an +influence in forcing the machine upward long before the +cliff is reached. + + + +CHAPTER XV. + +THE ELEMENT OF DANGER. + +That there is an element of danger in aviation is +undeniable, but it is nowhere so great as the public +imagines. Men are killed and injured in the operation +of flying machines just as they are killed and injured in +the operation of railways. Considering the character of +aviation the percentage of casualties is surprisingly +small. + +This is because the results following a collapse in the +air are very much different from what might be imagined. +Instead of dropping to the ground like a bullet an +aeroplane, under ordinary conditions will, when anything +goes wrong, sail gently downward like a parachute, +particularly if the operator is cool-headed and nervy enough +to so manipulate the apparatus as to preserve its equilibrium +and keep the machine on an even keel. + +Two Fields of Safety. + +At least one prominent aviator has declared that there +are two fields of safety--one close to the ground, and +the other well up in the air. In the first-named the fall +will be a slight one with little chance of the operator +being seriously hurt. From the field of high altitude the +the descent will be gradual, as a rule, the planes of the +machine serving to break the force of the fall. With a +cool-headed operator in control the aeroplane may be +even guided at an angle (about 1 to 8) in its descent so +as to touch the ground with a gliding motion and with +a minimum of impact. + +Such an experience, of course, is far from pleasant, +but it is by no means so dangerous as might appear. +There is more real danger in falling from an elevation +of 75 or 100 feet than there is from 1,000 feet, as in the +former case there is no chance for the machine to serve as +a parachute--its contact with the ground comes too +quickly. + +Lesson in Recent Accidents. + +Among the more recent fatalities in aviation are the +deaths of Antonio Fernandez and Leon Delagrange. The +former was thrown to the ground by a sudden stoppage +of his motor, the entire machine seeming to collapse. +It is evident there were radical defects, not only in the +motor, but in the aeroplane framework as well. At the +time of the stoppage it is estimated that Fernandez was +up about 1,500 feet, but the machine got no opportunity +to exert a parachute effect, as it broke up immediately. +This would indicate a fatal weakness in the structure +which, under proper testing, could probably have been +detected before it was used in flight. + +It is hard to say it, but Delagrange appears to have +been culpable to great degree in overloading his machine +with a motor equipment much heavier than it was +designed to sustain. He was 65 feet up in the air when +the collapse occurred, resulting in his death. As in the +case of Fernandez common-sense precaution would +doubtless have prevented the fatality. + +Aviation Not Extra Hazardous. + +All told there have been, up to the time of this writing +(April, 1910), just five fatalities in the history of power- +driven aviation. This is surprisingly low when the nature +of the experiments, and the fact that most of the +operators were far from having extended experience, is +taken into consideration. Men like the Wrights, Curtiss, +Bleriot, Farman, Paulhan and others, are now experts, +but there was a time, and it was not long ago, when they +were unskilled. That they, with numerous others less +widely known, should have come safely through their +many experiments would seem to disprove the prevailing +idea that aviation is an extra hazardous pursuit. + +In the hands of careful, quick-witted, nervy men the +sailing of an airship should be no more hazardous than +the sailing of a yacht. A vessel captain with common +sense will not go to sea in a storm, or navigate a weak, +unseaworthy craft. Neither should an aviator attempt +to sail when the wind is high and gusty, nor with a machine +which has not been thoroughly tested and found to +be strong and safe. + +Safer Than Railroading. + +Statistics show that some 12,000 people are killed and +72,000 injured every year on the railroads of the United +States. Come to think it over it is small wonder that +the list of fatalities is so large. Trains are run at high +speeds, dashing over crossings at which collisions are +liable to occur, and over bridges which often collapse +or are swept away by floods. Still, while the number of +casualties is large, the actual percentage is small considering +the immense number of people involved. + +It is so in aviation. The number of casualties is remarkably +small in comparison with the number of flights +made. In the hands of competent men the sailing of an +airship should be, and is, freer from risk of accident than +the running of a railway train. There are no rails to +spread or break, no bridges to collapse, no crossings at +which collisions may occur, no chance for some sleepy +or overworked employee to misunderstand the dispatcher's +orders and cause a wreck. + +Two Main Causes of Trouble. + +The two main causes of trouble in an airship leading +to disaster may be attributed to the stoppage of the +motor, and the aviator becoming rattled so that he loses +control of his machine. Modern ingenuity is fast developing +motors that almost daily become more and more +reliable, and experience is making aviators more and +more self-confident in their ability to act wisely and +promptly in cases of emergency. Besides this a satisfactory +system of automatic control is in a fair way +of being perfected. + +Occasionally even the most experienced and competent +of men in all callings become careless and by foolish +action invite disaster. This is true of aviators the same +as it is of railroaders, men who work in dynamite mills, +etc. But in nearly every instance the responsibility rests +with the individual; not with the system. There are +some men unfitted by nature for aviation, just as there +are others unfitted to be railway engineers. + + + +CHAPTER XVI. + +RADICAL CHANGES BEING MADE. + +Changes, many of them extremely radical in their nature, +are continually being made by prominent aviators, +and particularly those who have won the greatest amount +of success. Wonderful as the results have been few of +the aviators are really satisfied. Their successes have +merely spurred them on to new endeavors, the ultimate +end being the development of an absolutely perfect aircraft. + +Among the men who have been thus experimenting +are the Wright Brothers, who last year (1909) brought +out a craft totally different as regards proportions and +weight from the one used the preceding year. One +marked result was a gain of about 3 1/2 miles an hour in +speed. + +Dimensions of 1908 Machine. + +The 1908 model aeroplane was 40 by 29 feet over all. +The carrying surfaces, that is, the two aerocurves, were +40 by 6 feet, having a parabolical curve of one in twelve. +With about 70 square feet of surface in the rudders, the +total surface given was about 550 square feet. The +engine, which is the invention of the Wright brothers, +weighed, approximately, 200 pounds, and gave about 25 +horsepower at 1,400 revolutions per minute. The total +weight of the aeroplane, exclusive of passenger, but +inclusive of engine, was about 1,150 pounds. This result +showed a lift of a fraction over 2 1/4 pounds to the square +foot of carrying surface. The speed desired was 40 +miles an hour, but the machine was found to make only +a scant 39 miles an hour. The upright struts were +about 7/8-inch thick, the skids, 2 1/2 by 1 1/4 inches thick. + +Dimensions of 1909 Machine. + +The 1909 aeroplane was built primarily for greater +speed, and relatively heavier; to be less at the mercy +of the wind. This result was obtained as follows: The +aerocurves, or carrying surfaces, were reduced in dimensions +from 40 by 6 feet to 36 by 5 1/2 feet, the curve +remaining the same, one in twelve. The upright struts +were cut from seven-eighths inch to five-eighths inch, and +the skids from two and one-half by one and one-quarter +to two and one-quarter by one and three-eighths inches. +This result shows that there were some 81 square feet +of carrying surface missing over that of last year's +model. and some 25 pounds loss of weight. Relatively, +though, the 1909 model aeroplane, while actually 25 +pounds lighter, is really some 150 pounds heavier in the +air than the 1908 model, owing to the lesser square +feet of carrying surface. + +Some of the Results Obtained. + +Reducing the carrying surfaces from 6 to 5 1/2 feet +gave two results--first, less carrying capacity; and, second, +less head-on resistance, owing to the fact that the +extent of the parabolic curve in the carrying surfaces +was shortened. The "head-on" resistance is the retardance +the aeroplane meets in passing through the air, +and is counted in square feet. In the 1908 model the +curve being one in twelve and 6 feet deep, gave 6 inches +of head-on resistance. The plane being 40 feet spread, +gave 6 inches by 40 feet, or 20 square feet of head-on +resistance. Increasing this figure by a like amount for +each plane, and adding approximately 10 square feet for +struts, skids and wiring, we have a total of approximately, +50 square feet of surface for "head-on" resistance. + +In the 1909 aeroplane, shortening the curve 6 inches +at the parabolic end of the curve took off 1 inch of +head-on resistance. Shortening the spread of the planes +took off between 3 and 4 square feet of head-on resistance. +Add to this the total of 7 square feet, less curve +surface and about 1 square foot, less wire and woodwork +resistance, and we have a grand total of, approximately, +12 square feet of less "head-on" resistance over +the 1908 model. + +Changes in Engine Action. + +The engine used in 1909 was the same one used in +1908, though some minor changes were made as +improvements; for instance, a make and break spark was +used, and a nine-tooth, instead of a ten-tooth magneto +gear-wheel was used. This increased the engine revolutions +per minute from 1,200 to 1,400, and the propeller +revolutions per minute from 350 to 371, giving a propeller +thrust of, approximately, 170 foot pounds instead +of 153, as was had last year. + +More Speed and Same Capacity. + +One unsatisfactory feature of the 1909 model over +that of 1908, apparently, was the lack of inherent lateral +stability. This was caused by the lesser surface and +lesser extent of curvatures at the portions of the +aeroplane which were warped. This defect did not show so +plainly after Mr. Orville Wright had become fully +proficient in the handling of the new machine, and with +skillful management, the 1909 model aeroplane will be +just as safe and secure as the other though it will take +a little more practice to get that same degree of skill. + +To sum up: The aeroplane used in 1909 was 25 +pounds lighter, but really about 150 pounds heavier in +the air, had less head-on resistance, and greater +propeller thrust. The speed was increased from about 39 +miles per hour to 42 1/2 miles per hour. The lifting +capacity remained about the same, about 450 pounds +capacity passenger-weight, with the 1908 machine. In this +respect, the loss of carrying surface was compensated for +by the increased speed. + +During the first few flights it was plainly demonstrated +that it would need the highest skill to properly +handle the aeroplane, as first one end and then the other +would dip and strike the ground, and either tear the canvas +or slew the aeroplane around and break a skid. + +Wrights Adopt Wheeled Gears. + +In still another important respect the Wrights, so far +as the output of one of their companies goes, have made +a radical change. All the aeroplanes turned out by the +Deutsch Wright Gesellschaft, according to the German +publication, _Automobil-Welt_, will hereafter be equipped +with wheeled running gears and tails. The plan of this +new machine is shown in the illustration on page 145. +The wheels are three in number, and are attached one +to each of the two skids, just under the front edge of +the planes, and one forward of these, attached to a cross- +member. It is asserted that with these wheels the +teaching of purchasers to operate the machines is much +simplified, as the beginners can make short flights on +their own account without using the starting derrick. + +This is a big concession for the Wrights to make, as +they have hitherto adhered stoutly to the skid gear. +While it is true they do not control the German company +producing their aeroplanes, yet the nature of their +connection with the enterprise is such that it may be +taken for granted no radical changes in construction +would be made without their approval and consent. + +Only Three Dangerous Rivals. + +Official trials with the 1909 model smashed many records +and leave the Wright brothers with only three dangerous +rivals in the field, and with basic patents which +cover the curve, warp and wing-tip devices found on +all the other makes of aeroplanes. These three rivals +are the Curtiss and Voisin biplane type and the Bleriot +monoplane pattern. + +The Bleriot monoplane is probably the most dangerous +rival, as this make of machine has a record of 54 +miles per hour, has crossed the English channel, and +has lifted two passengers besides the operator. The latest type +of this machine only weighs 771.61 pounds complete, +without passengers, and will lift a total passenger +weight of 462.97 pounds, which is a lift of 5.21 pounds +to the square foot. This is a better result than those +published by the Wright brothers, the best noted being +4.25 pounds per square foot. + +Other Aviators at Work. + +The Wrights, however, are not alone in their efforts +to promote the efficiency of the flying machine. Other +competent inventive aviators, notably Curtiss, Voisin, +Bleriot and Farman, are close after them. The Wrights, +as stated, have a marked advantage in the possession of +patents covering surface plane devices which have thus +far been found indispensable in flying machine construction. +Numerous law suits growing out of alleged infringements +of these patents have been started, and +others are threatened. What effect these actions will +have in deterring aviators in general from proceeding +with their experiments remains to be seen. + +In the meantime the four men named--Curtiss, Voisin, +Bleriot and Farman--are going ahead regardless of +consequences, and the inventive genius of each is so strong +that it is reasonable to expect some remarkable developments +in the near future. + +Smallest of Flying Machines. + +To Santos Dumont must be given the credit of producing +the smallest practical flying machine yet constructed. +True, he has done nothing remarkable with it +in the line of speed, but he has demonstrated the fact +that a large supporting surface is not an essential feature. + +This machine is named "La Demoiselle." It is a monoplane +of the dihedral type, with a main plane on each +side of the center. These main planes are of 18 foot +spread, and nearly 6 1/2 feet in depth, giving approximately +115 feet of surface area. The total weight is 242 pounds, +which is 358 pounds less than any other machine which +has been successfully used. The total depth from front +to rear is 26 feet. + +The framework is of bamboo, strengthened and held +taut with wire guys. + +Have One Rule in Mind. + +In this struggle for mastery in flying machine efficiency +all the contestants keep one rule in mind, and this +is: + +"The carrying capacity of an aeroplane is governed +by the peripheral curve of its carrying surfaces, plus the +speed; and the speed is governed by the thrust of the +propellers, less the 'head-on' resistance." + +Their ideas as to the proper means of approaching +the proposition may, and undoubtedly are, at variance, +but the one rule in solving the problem of obtaining the +greatest carrying capacity combined with the greatest +speed, obtains in all instances. + + + +CHAPTER XVII. + +SOME OF THE NEW DESIGNS. + +Spurred on by the success attained by the more experienced +and better known aviators numerous inventors +of lesser fame are almost daily producing practical flying +machines varying radically in construction from +those now in general use. + +One of these comparatively new designs is the Van +Anden biplane, made by Frank Van Anden of Islip, +Long Island, a member of the New York Aeronautic +Society. While his machine is wholly experimental, +many successful short flights were made with it last fall +(1909). One flight, made October 19th, 1909, is of particular +interest as showing the practicability of an automatic +stabilizing device installed by the inventor. The +machine was caught in a sudden severe gust of wind +and keeled over, but almost immediately righted itself, +thus demonstrating in a most satisfactory manner the +value of one new attachment. + +Features of Van Anden Model. + +In size the surfaces of the main biplane are 26 feet +in spread, and 4 feet in depth from front to rear. The +upper and lower planes are 4 feet apart. Silkolene +coated with varnish is used for the coverings. Ribs +(spruce) are curved one inch to the foot, the deepest +part of the curve (4 inches) being one foot back from the +front edge of the horizontal beam. Struts (also of +spruce, as is all the framework) are elliptical in shape. +The main beams are in three sections, nearly half round +in form, and joined by metal sleeves. + +There is a two-surface horizontal rudder, 2x2x4 feet, +in front. This is pivoted at its lateral center 8 feet from +the front edge of the main planes. In the rear is another +two-surface horizontal rudder 2x2x2 1/2 feet, pivoted +in the same manner as the front one, 15 feet from the +rear edges of the main planes. + +Hinged to the rear central strut of the rear rudder +is a vertical rudder 2 feet high by 3 feet in length. + +The Method of Control. + +In the operation of these rudders--both front and rear +--and the elevation and depression of the main planes, +the Curtiss system is employed. Pushing the steering- +wheel post outward depresses the front edges of the +planes, and brings the machine downward; pulling the +steering-wheel post inward elevates the front edges of +the planes and causes the machine to ascend. + +Turning the steering wheel itself to the right swings +the tail rudder to the left, and the machine, obeying this +like a boat, turns in the same direction as the wheel +is turned. By like cause turning the wheel to the left +turns the machine to the left. + +Automatic Control of Wings. + +There are two wing tips, each of 6 feet spread (length) +and 2 feet from front to rear. These are hinged half +way between the main surfaces to the two outermost +rear struts. Cables run from these to an automatic +device working with power from the engine, which automatically +operates the tips with the tilting of the +machine. Normally the wing tips are held horizontal +by stiff springs introduced in the cables outside of the +device. + +It was the successful working of this device which +righted the Van Anden craft when it was overturned in +the squall of October 19th, 1909. Previous to that +occurrence Mr. Van Anden had looked upon the device +as purely experimental, and had admitted that he had +grave uncertainty as to how it would operate in time of +emergency. He is now quoted as being thoroughly satisfied +with its practicability. It is this automatic device +which gives the Van Anden machine at least one distinctively +new feature. + +While on this subject it will not be amiss to add that +Mr. Curtiss does not look kindly on automatic control. +"I would rather trust to my own action than that of a +machine," he says. This is undoubtedly good logic so +far as Mr. Curtiss is concerned, but all aviators are not +so cool-headed and resourceful. + +Motive Power of Van Anden. + +A 50-horsepower "H-F" water cooled motor drives a +laminated wood propeller 6 feet in diameter, with a 17 +degree pitch at the extremities, increasing toward the +hub. The rear end of the motor is about 6 inches back +from the rear transverse beam and the engine shaft is +in a direct line with the axes of the two horizontal rudders. +An R. I. V. ball bearing carries the shaft at this +point. Flying, the motor turns at about 800 revolutions +per minute, delivering 180 pounds pull. A test of the +motor running at 1,200 showed a pull of 250 pounds on +the scales. + +Still Another New Aeroplane. + +Another new aeroplane is that produced by A. M. +Herring (an old-timer) and W. S. Burgess, under the +name of the Herring-Burgess. This is also equipped +with an automatic stability device for maintaining the +balance transversely. The curvature of the planes is +also laid out on new lines. That this new plan is +effective is evidenced by the fact that the machine has +been elevated to an altitude of 40 feet by using one-half +the power of the 30-horsepower motor. + +The system of rudder and elevation control is very +simple. The aviator sits in front of the lower plane, +and extending his arms, grasps two supports which extend +down diagonally in front. On the under side of +these supports just beneath his fingers are the controls +which operate the vertical rudder, in the rear. Thus, if +he wishes to turn to the right, he presses the control +under the fingers of his right hand; if to the left, that +under the fingers of his left hand. The elevating rudder +is operated by the aviator's right foot, the control +being placed on a foot-rest. + +Motor Is Extremely Light. + +Not the least notable feature of the craft is its motor. +Although developing, under load, 30-horsepower, or that +of an ordinary automobile, it weighs, complete, hardly +100 pounds. Having occasion to move it a little distance +for inspection, Mr. Burgess picked it up and walked +off with it--cylinders, pistons, crankcase and all, even +the magneto, being attached. There are not many 30- +horsepower engines which can be so handled. Everything +about it is reduced to its lowest terms of simplicity, +and hence, of weight. A single camshaft operates +not only all of the inlet and exhaust valves, but the magneto +and gear water pump, as well. The motor is placed +directly behind the operator, and the propeller is directly +mounted on the crankshaft. + +This weight of less than 100 pounds, it must be +remembered, is not for the motor alone; it includes the +entire power plant equipment. + +The "thrust" of the propeller is also extraordinary, +being between 250 and 260 pounds. The force of the +wind displacement is strong enough to knock down a +good-sized boy as one youngster ascertained when he +got behind the propeller as it was being tested. He +was not only knocked down but driven for some distance +away from the machine. The propeller has four +blades which are but little wider than a lath. + +Machine Built by Students. + +Students at the University of Pennsylvania, headed by +Laurence J. Lesh, a protege of Octave Chanute, have +constructed a practical aeroplane of ordinary maximum +size, in which is incorporated many new ideas. The +most unique of these is to be found in the steering gear, +and the provision made for the accommodation of a +pupil while taking lessons under an experienced aviator. + +Immediately back of the aviator is an extra seat and +an extra steering wheel which works in tandem style +with the front wheel. By this arrangement a beginner +may be easily and quickly taught to have perfect control +of the machine. These tandem wheels are also +handy for passengers who may wish to operate the car +independently of one another, it being understood, of +course, that there will be no conflict of action. + +Frame Size and Engine Power. + +The frame has 36 feet spread and measures 35 feet +from the front edge to the end of the tail in the rear. It +is equipped with two rear propellers operated by a Ramsey +8-cylinder motor of 50 horsepower, placed horizontally +across the lower plane, with the crank shaft running +clear through the engine. + +The "Pennsylvania I" is the first two-propeller biplane +chainless car, this scheme having been adopted in order +to avoid the crossing of chains. The lateral control is +by a new invention by Octave Chanute and Laurence J. +Lesh, for which Lesh is now applying for a patent. The +device was worked out before the Wright brothers' suit +was begun, and is said to be superior to the Wright +warping or the Curtiss ailerons. The landing device is +also new in design. This aeroplane will weigh about +1,500 pounds, and will carry fuel for a flight of 150 miles, +and it is expected to attain a speed of at least 45 miles +an hour. + +There are others, lots of them, too numerous in fact +to admit of mention in a book of this size. + + + +CHAPTER XVIII. + +DEMAND FOR FLYING MACHINES. + +As a commercial proposition the manufacture and sale +of motor-equipped aeroplanes is making much more +rapid advance than at first obtained in the similar +handling of the automobile. Great, and even phenomenal, +as was the commercial development of the motor +car, that of the flying machine is even greater. This is +a startling statement, but it is fully warranted by the +facts. + +It is barely more than a year ago (1909) that attention +was seriously attracted to the motor-equipped aeroplane +as a vehicle possible of manipulation by others +than professional aviators. Up to that time such actual +flights as were made were almost exclusively with the +sole purpose of demonstrating the practicability of the +machine, and the merits of the ideas as to shape, engine +power, etc., of the various producers. + +Results of Bleriot's Daring. + +It was not until Bleriot flew across the straits of +Dover on July 25th, 1909, that the general public awoke +to a full realization of the fact that it was possible for +others than professional aviators to indulge in aviation. +Bleriot's feat was accepted as proof that at last an +absolutely new means of sport, pleasure and research, +had been practically developed, and was within the +reach of all who had the inclination, nerve and financial +means to adopt it. + +From this event may be dated the birth of the modern +flying machine into the world of business. The automobile +was taken up by the general public from the +very start because it was a proposition comparatively +easy of demonstration. There was nothing mysterious +or uncanny in the fact that a wheeled vehicle could be +propelled on solid, substantial roads by means of engine +power. And yet it took (comparatively speaking) a long +time to really popularize the motor car. + +Wonderful Results in a Year. + +Men of large financial means engaged in the manufacture +of automobiles, and expended fortunes in attracting +public attention to them through the medium of +advertisements, speed and road contests, etc. By these +means a mammoth business has been built up, but bringing +this business to its present proportions required +years of patient industry and indomitable pluck. + +At this writing, less than a year from the day when +Bleriot crossed the channel, the actual sales of flying +machines outnumber the actual sales of automobiles in +the first year of their commercial development. This +may appear incredible, but it is a fact as statistics will +show. + +In this connection we should take into consideration +the fact that up to a year ago there was no serious intention +of putting flying machines on the market; no +preparations had been made to produce them on a commercial +scale; no money had been expended in advertisements +with a view to selling them. + +Some of the Actual Results. + +Today flying machines are being produced on a commercial +basis, and there is a big demand for them. The +people making them are overcrowded with orders. Some +of the producers are already making arrangements to +enlarge their plants and advertise their product for sale +the same as is being done with automobiles, while a +number of flying machine motor makers are already +promoting the sale of their wares in this way. + +Here are a few actual figures of flying machine sales +made by the more prominent producers since July 25th, +1909. + +Santos Dumont, 90 machines; Bleriot, 200; Farman, +130; Clemenceau-Wright, 80; Voisin, 100; Antoinette, +100. Many of these orders have been filled by delivery +of the machines, and in others the construction work +is under way. + +The foregoing are all of foreign make. In this country +Curtiss and the Wrights are engaged in similar +work, but no actual figures of their output are obtainable. + +Larger Plants Are Necessary. + +And this situation exists despite the fact that none of +the producers are really equipped with adequate plants +for turning out their machines on a modern, business- +like basis. The demand was so sudden and unexpected +that it found them poorly prepared to meet it. This, +however, is now being remedied by the erection of special +plants, the enlargement of others, and the introduction +of new machinery and other labor-saving conveniences. + +Companies, with large capitalization, to engage in the +exclusive production of airships are being organized in +many parts of the world. One notable instance of this +nature is worth quoting as illustrative of the manner +in which the production of flying machines is being +commercialized. This is the formation at Frankfort, +Germany, of the Flugmaschine Wright, G. m. b. H., with +a capital of $119,000, the Krupps, of Essen, being interested. + +Prices at Which Machines Sell. + +This wonderful demand from the public has come +notwithstanding the fact that the machines, owing to lack +of facilities for wholesale production, are far from being +cheap. Such definite quotations as are made are +on the following basis: + +Santos Dumont--List price $1,000, but owing to the +rush of orders agents are readily getting from $1,300 to +$1,500. This is the smallest machine made. + +Bleriot--List price $2,500. This is for the cross- +channel type, with Anzani motor. + +Antoinette--List price from $4,000 to $5,000, according +to size. + +Wright--List price $5,600. + +Curtiss--List price $5,000. + +There is, however, no stability in prices as purchasers +are almost invariably ready to pay a considerable premium +to facilitate delivery. + +The motor is the most expensive part of the flying +machine. Motor prices range from $500 to $2,000, this +latter amount being asked for the Curtiss engine. + +Systematic Instruction of Amateurs. + +In addition to the production of flying machines many +of the experienced aviators are making a business of +the instruction of amateurs. Curtiss and the Wrights +in this country have a number of pupils, as have also +the prominent foreigners. Schools of instruction are +being opened in various parts of the world, not alone as +private money-making ventures, but in connection with +public educational institutions. One of these latter is +to be found at the University of Barcelona, Spain. + +The flying machine agent, the man who handles the +machines on a commission, has also become a known +quantity, and will soon be as numerous as his brother +of the automobile. The sign "John Bird, agent for +Skimmer's Flying Machine," is no longer a curiosity. + +Yes, the Airship Is Here. + +From all of which we may well infer that the flying +machine in practical form has arrived, and that it is +here to stay. It is no exaggeration to say that the time +is close at hand when people will keep flying machines +just as they now keep automobiles, and that pleasure +jaunts will be fully as numerous and popular. With +the important item of practicability fully demonstrated, +"Come, take a trip in my airship," will have more real +significance than now attaches to the vapid warblings +of the vaudeville vocalist. + +As a further evidence that the airship is really here, +and that its presence is recognized in a business way, +the action of life and accident insurance companies is +interesting. Some of them are reconstructing their policies +so as to include a special waiver of insurance by +aviators. Anything which compels these great corporations +to modify their policies cannot be looked upon as +a mere curiosity or toy. + +It is some consolation to know that the movement in +this direction is not thus far widespread. Moreover it +is more than probable that the competition for business +will eventually induce the companies to act more +liberally toward aviators, especially as the art of aviation +advances. + + + +CHAPTER XIX. + +LAW OF THE AIRSHIP. + +Successful aviation has evoked some peculiar things +in the way of legal action and interpretation of the law. + +It is well understood that a man's property cannot +be used without his consent. This is an old established +principle in common law which holds good today. + +The limits of a man's property lines, however, have +not been so well understood by laymen. According to +eminent legal authorities such as Blackstone, Littleton +and Coke, the "fathers of the law," the owner of realty +also holds title above and below the surface, and this +theory is generally accepted without question by the +courts. + +Rights of Property Owners. + +In other words the owner of realty also owns the sky +above it without limit as to distance. He can dig as +deep into his land, or go as high into the air as he desires, +provided he does not trespass upon or injure similar +rights of others. + +The owner of realty may resist by force, all other +means having failed, any trespass upon, or invasion of +his property. Other people, for instance, may not enter +upon it, or over or under it, without his express permission +and consent. There is only one exception, and +this is in the case of public utility corporations such as +railways which, under the law of eminent domain, may +condemn a right of way across the property of an obstinate owner +who declines to accept a fair price for the +privilege. + +Privilege Sharply Confined. + +The law of eminent domain may be taken advantage +of only by corporations which are engaged in serving +the public. It is based upon the principle that the +advancement and improvement of a community is of more +importance and carries with it more rights than the +interests of the individual owner. But even in cases where +the right of eminent domain is exercised there can be no +confiscation of the individual's property. + +Exercising the right of eminent domain is merely +obtaining by public purchase what is held to be essential +to the public good, and which cannot be secured by private +purchase. When eminent domain proceedings are +resorted to the court appoints appraisers who determine +upon the value of the property wanted, and this value +(in money) is paid to the owner. + +How It Affects Aviation. + +It should be kept in mind that this privilege of the +"right of eminent domain" is accorded only to corporations +which are engaged in serving the public. Individuals +cannot take advantage of it. Thus far all aviation +has been conducted by individuals; there are no flying +machine or airship corporations regularly engaged in the +transportation of passengers, mails or freight. + +This leads up to the question "What would happen if +realty owners generally, or in any considerable numbers. +should prohibit the navigation of the air above their +holdings?" It is idle to say such a possibility is ridiculous-- +it is already an actuality in a few individual instances. + +One property owner in New Jersey, a justice of the +peace, maintains a large sign on the roof of his house +warning aviators that they must not trespass upon his +domain. That he is acting well within his rights in doing +this is conceded by legal authorities. + +Hard to Catch Offenders. + +But, suppose the alleged trespass is committed, what +is the property owner going to do about it? He must +first catch the trespasser and this would be a pretty hard +job. He certainly could not overtake him, unless he +kept a racing aeroplane for this special purpose. It +would be equally difficult to indentify the offender after +the offense had been committed, even if he were located, +as aeroplanes carry no license numbers. + +Allowing that the offender should be caught the only +recourse of the realty owner is an action for damages. +He may prevent the commission of the offense by force +if necessary, but after it is committed he can only sue +for damages. And in doing this he would have a lot of +trouble. + +Points to Be Proven. + +One of the first things the plaintiff would be called +upon to prove would be the elevation of the machine. +If it were reasonably close to the ground there would, +of course, be grave risk of damage to fences, shrubbery, +and other property, and the court would be justified in +holding it to be a nuisance that should be suppressed. + +If, on the other hand; the machine was well up in the +air, but going slowly, or hovering over the plaintiff's +property, the court might be inclined to rule that it +could not possibly be a nuisance, but right here the court +would be in serious embarrassment. By deciding that +it was not a nuisance he would virtually override the +law against invasion of a man's property without his +consent regardless of the nature of the invasion. By +the same decision he would also say in effect that, if one +flying machine could do this a dozen or more would +have equal right to do the same thing. While one machine +hovering over a certain piece of property may be +no actual nuisance a dozen or more in the same position +could hardly be excused. + +Difficult to Fix Damages. + +Such a condition would tend to greatly increase the +risk of accident, either through collision, or by the +carelessness +of the aviators in dropping articles which might +cause damages to the people or property below. In +such a case it would undoubtedly be a nuisance, and +in addition to a fine, the offender would also be liable +for the damages. + +Taking it for granted that no actual damage is done, +and the owner merely sues on account of the invasion +of his property, how is the amount of compensation to +be fixed upon? The owner has lost nothing; no part of +his possessions has been taken away; nothing has been +injured or destroyed; everything is left in exactly the +same condition as before the invasion. And yet, if the +law is strictly interpreted, the offender is liable. + +Right of Way for Airships. + +Somebody has suggested the organization of flying- +machine corporations as common carriers, which would +give them the right of eminent domain with power to +condemn a right of way. But what would they condemn? +There is nothing tangible in the air. Railways +in condemning a right of way specify tangible property +(realty) within certain limits. How would an aviator +designate any particular right of way through the air +a certain number of feet in width, and a certain distance +from the ground? + +And yet, should the higher courts hold to the letter +of the law and decide that aviators have no right to +navigate their craft over private property, something +will have to be done to get them out of the dilemma, as +aviation is too far advanced to be discarded. Fortunately +there is little prospect of any widespread antagonism +among property owners so long as aviators refrain +from making nuisances of themselves. + +Possible Solution Offered. + +One possible solution is offered and that is to confine +the path of airships to the public highways so that nobody's +property rights would be invaded. In addition, +as a matter of promoting safety for both operators and +those who may happen to be beneath the airships as +they pass over a course, adoption of the French rules +are suggested. These are as follows: + +Aeroplanes, when passing, must keep to the right, and +pass at a distance of at least 150 feet. They are free +from this rule when flying at altitudes of more than 100 +feet. Every machine when flying at night or during +foggy weather must carry a green light on the right, +and a red light on the left, and a white headlight on the +front. + +These are sensible rules, but may be improved upon +by the addition of a signal system of some kind, either +horn, whistle or bell. + +Responsibility of Aviators. + +Mr. Jay Carver Bossard, in recent numbers of _Fly_, +brings out some curious and interesting legal points in +connection with aviation, among which are the following: + +"Private parties who possess aerial craft, and desire +to operate the same in aerial territory other than their +own, must obtain from land owners special permission +to do so, such permission to be granted only by agreement, +founded upon a valid consideration. Otherwise, +passing over another's land will in each instance amount +to a trespass. + +"Leaving this highly technical side of the question, +let us turn to another view: the criminal and tort liability +of owners and operators to airship passengers. If +A invites B to make an ascension with him in his machine, +and B, knowing that A is merely an enthusiastic +amateur and far from being an expert, accepts and is +through A's innocent negligence injured, he has no +grounds for recovery. But if A contracts with B, to +transport him from one place to another, for a consideration, +and B is injured by the poor piloting of A, +A would be liable to B for damages which would result. +Now in order to safeguard such people as B, curious to +the point of recklessness, the law will have to require +all airship operators to have a license, and to secure +this license airship pilots will have to meet certain +requirements. Here again is a question. Who is going +to say whether an applicant is competent to pilot a balloon +or airship? + +Fine for an Aeronaut. + +"An aeroplane while maneuvering is suddenly caught +by a treacherous gale and swept to the ground. A crowd +of people hasten over to see if the aeronaut is injured, +and in doing so trample over Tax-payer Smith's garden, +much to the detriment of his growing vegetables and +flowers. Who is liable for the damages? Queer as it +may seem, a case very similar to this was decided in +1823, in the New York supreme court, and it was held +that the aeronaut was liable upon the following grounds: +'To render one man liable in trespass for the acts of +others, it must appear either that they acted in concert, +or that the act of the one, ordinarily and naturally produced +the acts of the others, Ascending in a balloon is +not an unlawful act, but it is certain that the aeronaut +has no control over its motion horizontally, but is at +the sport of the wind, and is to descend when and how +he can. His reaching the earth is a matter of hazard. +If his descent would according to the circumstances +draw a crowd of people around him, either out of curiosity, +or for the purpose of rescuing him from a perilous +situation, all this he ought to have foreseen, and must be +responsible for.' + +Air Not Really Free. + +"The general belief among people is, that the air is +free. Not only free to breathe and enjoy, but free to +travel in, and that no one has any definite jurisdiction +over, or in any part of it. Now suppose this were made a +legal doctrine. Would a murder perpetrated above the +clouds have to go unpunished? Undoubtedly. For felonies +committed upon the high seas ample provision is +made for their punishment, but new provisions will have +to be made for crimes committed in the air. + +Relations of Owner and Employee. + +"It is a general rule of law that a master is bound to +provide reasonably safe tools, appliances and machines +for his servant. How this rule is going to be applied +in cases of aeroplanes, remains to be seen. The aeroplane +owner who hires a professional aeronaut, that is, +one who has qualified as an expert, owes him very little +legal duty to supply him with a perfect aeroplane. The +expert is supposed to know as much regarding the machine +as the owner, if not more, and his acceptance of +his position relieves the owner from liability. When +the owner hires an amateur aeronaut to run the aeroplane, and +teaches him how to manipulate it, even though +the prescribed manner of manipulation will make flight +safe, nevertheless if the machine is visibly defective, or +known to be so, any injury which results to the aeronaut +the owner is liable for. + +As to Aeroplane Contracts. + +"At the present time there are many orders being +placed with aeroplane manufacturing companies. There +are some unique questions to be raised here under the +law of contract. It is an elementary principle of law +that no one can be compelled to complete a contract +which in itself is impossible to perform. For instance, +a contract to row a boat across the Atlantic in two +weeks, for a consideration, could never be enforced because +it is within judicial knowledge that such an undertaking +is beyond human power. Again, contracts formed +for the doing of acts contrary to nature are never +enforcible, and here is where our difficulty comes in. Is +it possible to build a machine or species of craft which +will transport a person or goods through the air? The +courts know that balloons are practical; that is, they +know that a bag filled with gas has a lifting power and +can move through the air at an appreciable height. +Therefore, a contract to transport a person in such manner +is a good contract, and the conditions being favorable +could undoubtedly be enforced. But the passengers' +right of action for injury would be very limited. + +No Redress for Purchasers. + +"In the case of giving warranties on aeroplanes, we +have yet to see just what a court is going to say. It is +easy enough for a manufacturer to guarantee to build a +machine of certain dimensions and according to certain +specifications, but when he inserts a clause in the contract to +the effect that the machine will raise itself from +the surface of the earth, defy the laws of gravity, and +soar in the heavens at the will of the aviator, he is to +say the least contracting to perform a miracle. + +"Until aeroplanes have been made and accepted as +practical, no court will force a manufacturer to turn out +a machine guaranteed to fly. So purchasers can well +remember that if their machines refuse to fly they have +no redress against the maker, for he can always say, +'The industry is still in its experimental stage.' In +contracting for an engine no builder will guarantee that +the particular engine will successfully operate the aeroplane. +In fact he could never be forced to live up to +such an agreement, should he agree to a stipulation of +that sort. The best any engine maker will guarantee +is to build an engine according to specifications." + + + +CHAPTER XX. + +SOARING FLIGHT. + +By Octave Chanute. + +[5]There is a wonderful performance daily exhibited in +southern climes and occasionally seen in northerly +latitudes in summer, which has never been thoroughly +explained. It is the soaring or sailing flight of certain +varieties of large birds who transport themselves on rigid, +unflapping wings in any desired direction; who in winds +of 6 to 20 miles per hour, circle, rise, advance, return and +remain aloft for hours without a beat of wing, save for +getting under way or convenience in various maneuvers. +They appear to obtain from the wind alone all the necessary +energy, even to advancing dead against that wind. +This feat is so much opposed to our general ideas of +physics that those who have not seen it sometimes deny +its actuality, and those who have only occasionally +witnessed it subsequently doubt the evidence of their own +eyes. Others, who have seen the exceptional performances, +speculate on various explanations, but the majority +give it up as a sort of "negative gravity." + +[5] Aeronautics. + +Soaring Power of Birds. + +The writer of this paper published in the "Aeronautical +Annual" for 1896 and 1897 an article upon the sailing +flight of birds, in which he gave a list of the authors who +had described such flight or had advanced theories for +its explanation, and he passed these in review. He also +described his own observations and submitted some computations +to account for the observed facts. These computations +were correct as far as they went, but they were +scanty. It was, for instance, shown convincingly by +analysis that a gull weighing 2.188 pounds, with a total +supporting surface of 2.015 square feet, a maximum body +cross-section of 0.126 square feet and a maximum cross- +section of wing edges of 0.098 square feet, patrolling on +rigid wings (soaring) on the weather side of a steamer +and maintaining an upward angle or attitude of 5 degrees +to 7 degrees above the horizon, in a wind blowing 12.78 +miles an hour, which was deflected upward 10 degrees +to 20 degrees by the side of the steamer (these all being +carefully observed facts), was perfectly sustained at its +own "relative speed" of 17.88 miles per hour and extracted +from the upward trend of the wind sufficient energy +to overcome all the resistances, this energy +amounting to 6.44 foot-pounds per second. + +Great Power of Gulls. + +It was shown that the same bird in flapping flight in +calm air, with an attitude or incidence of 3 degrees to 5 +degrees above the horizon and a speed of 20.4 miles an +hour was well sustained and expended 5.88 foot-pounds +per second, this being at the rate of 204 pounds sustained +per horsepower. It was stated also that a gull in its observed +maneuvers, rising up from a pile head on unflapping +wings, then plunging forward against the wind and +subsequently rising higher than his starting point, must +either time his ascents and descents exactly with the +variations in wind velocities, or must meet a wind billow +rotating on a horizontal axis and come to a poise on its +crest, thus availing of an ascending trend. + +But the observations failed to demonstrate that the +variations of the wind gusts and the movements of the +bird were absolutely synchronous, and it was conjectured +that the peculiar shape of the soaring wing of certain +birds, as differentiated from the flapping wing, might, +when experimented upon, hereafter account for the performance. + +Mystery to be Explained. + +These computations, however satisfactory they were +for the speed of winds observed, failed to account for the +observed spiral soaring of buzzards in very light winds +and the writer was compelled to confess: "Now, this +spiral soaring in steady breezes of 5 to 10 miles per hour +which are apparently horizontal, and through which the +bird maintains an average speed of about 20 miles an +hour, is the mystery to be explained. It is not accounted +for, quantitatively, by any of the theories which have +been advanced, and it is the one performance which has +led some observers to claim that it was done through +'aspiration.' i, e., that a bird acted upon by a current, +actually drew forward into that current against its exact +direction of motion." + +Buzzards Soar in Dead Calm. + +A still greater mystery was propounded by the few +observers who asserted that they had seen buzzards soaring +in a dead calm, maintaining their elevation and their +speed. Among these observers was Mr. E. C. Huffaker, +at one time assistant experimenter for Professor Langley. +The writer believed and said then that he must in some +way have been mistaken, yet, to satisfy himself, he paid +several visits to Mr. Huffaker, in Eastern Tennessee and +took along his anemometer. He saw quite a number of +buzzards sailing at a height of 75 to 100 feet in breezes +measuring 5 or 6 miles an hour at the surface of the +ground, and once he saw one buzzard soaring apparently +in a dead calm. + +The writer was fairly baffled. The bird was not simply +gliding, utilizing gravity or acquired momentum, he was +actually circling horizontally in defiance of physics and +mathematics. It took two years and a whole series of +further observations to bring those two sciences into +accord with the facts. + +Results of Close Observations. + +Curiously enough the key to the performance of circling +in a light wind or a dead calm was not found +through the usual way of gathering human knowledge, +i. e., through observations and experiment. These had +failed because I did not know what to look for. The +mystery was, in fact, solved by an eclectic process of +conjecture and computation, but once these computations +indicated what observations should be made, the results +gave at once the reasons for the circling of the birds, for +their then observed attitude, and for the necessity of an +independent initial sustaining speed before soaring began. +Both Mr. Huffaker and myself verified the data +many times and I made the computations. + +These observations disclosed several facts: + +1st.--That winds blowing five to seventeen miles per +hour frequently had rising trends of 10 degrees to 15 +degrees, and that upon occasions when there seemed to be +absolutely no wind, there was often nevertheless a local +rising of the air estimated at a rate of four to eight miles +or more per hour. This was ascertained by watching +thistledown, and rising fogs alongside of trees or hills of +known height. Everyone will readily realize that when +walking at the rate of four to eight miles an hour in a +dead calm the "relative wind" is quite inappreciable to +the senses and that such a rising air would not be noticed. + +2nd.--That the buzzard, sailing in an apparently dead +horizontal calm, progressed at speeds of fifteen to eighteen +miles per hour, as measured by his shadow on the +ground. It was thought that the air was then possibly +rising 8.8 feet per second, or six miles per hour. + +3rd.--That when soaring in very light winds the angle +of incidence of the buzzards was negative to the horizon +--i. e., that when seen coming toward the eye, the afternoon +light shone on the back instead of on the breast, +as would have been the case had the angle been inclined +above the horizon. + +4th.--That the sailing performance only occurred after +the bird had acquired an initial velocity of at least fifteen +or eighteen miles per hour, either by industrious flapping +or by descending from a perch. + +An Interesting Experiment. + +5th.--That the whole resistance of a stuffed buzzard, +at a negative angle of 3 degrees in a current of air of +15.52 miles per hour, was 0.27 pounds. This test was +kindly made for the writer by Professor A. F. Zahm in +the "wind tunnel" of the Catholic University at Washington, +D. C., who, moreover, stated that the resistance +of a live bird might be less, as the dried plumage could +not be made to lie smooth. + +This particular buzzard weighed in life 4.25 pounds, +the area of his wings and body was 4.57 square feet, the +maximum cross-section of his body was 0.110 square feet, +and that of his wing edges when fully extended was +0.244 square feet. + +With these data, it became surprisingly easy to compute +the performance with the coefficients of Lilienthal +for various angles of incidence and to demonstrate how +this buzzard could soar horizontally in a dead horizontal +calm, provided that it was not a vertical calm, and that +the air was rising at the rate of four or six miles per +hour, the lowest observed, and quite inappreciable without +actual measuring. + +Some Data on Bird Power. + +The most difficult case is purposely selected. For if +we assume that the bird has previously acquired an initial +minimum speed of seventeen miles an hour (24.93 +feet per second, nearly the lowest measured), and that +the air was rising vertically six miles an hour (8.80 feet +per second), then we have as the trend of the "relative +wind" encountered: + + 6 + -- = 0.353, or the tangent of 19 degrees 26'. + 17 + +which brings the case into the category of rising wind +effects. But the bird was observed to have a negative +angle to the horizon of about 3 degrees, as near as could be +guessed, so that his angle of incidence to the "relative +wind" was reduced to 16 degrees 26'. + +The relative speed of his soaring was therefore: + +Velocity = square root of (17 squared + 6 squared) = 18.03 miles +per hour. + +At this speed, using the Langley co-efficient recently +practically confirmed by the accurate experiments of Mr. +Eiffel, the air pressure would be: + +18.03 squared X 0.00327 = 1.063 pounds per square foot. + +If we apply Lilienthal's co-efficients for an angle of +6 degrees 26', we have for the force in action: + +Normal: 4.57 X 1.063 X 0.912 = 4.42 pounds. + +Tangential: 4.57 X 1.063 X 0.074 = - 0.359 pounds, +which latter, being negative, is a propelling force. + +Results Astonish Scientists. + +Thus we have a bird weighing 4.25 pounds not only +thoroughly supported, but impelled forward by a force +of 0.359 pounds, at seventeen miles per hour, while the +experiments of Professor A. F. Zahm showed that the +resistance at 15.52 miles per hour was only 0.27 pounds, + 17 squared +or 0.27 X ------- = 0.324 pounds, at seventeen miles an + 15.52 squared +hour. + +These are astonishing results from the data obtained, +and they lead to the inquiry whether the energy of the +rising air is sufficient to make up the losses which occur +by reason of the resistance and friction of the bird's body +and wings, which, being rounded, do not encounter air +pressures in proportion to their maximum cross-section. + +We have no accurate data upon the co-efficients to apply +and estimates made by myself proved to be much +smaller than the 0.27 pounds resistance measured by +Professor Zahm, so that we will figure with the latter +as modified. As the speed is seventeen miles per hour, or +24.93 feet per second, we have for the work: + +Work done, 0.324 X 24.93 = 8.07 foot pounds per second. + +Endorsed by Prof. Marvin. + +Corresponding energy of rising air is not sufficient at +four miles per hour. This amounts to but 2.10 foot pounds +per second, but if we assume that the air was rising at +the rate of seven miles per hour (10.26 feet per second), +at which the pressure with the Langley coefficient would +be 0.16 pounds per square foot, we have on 4.57 square +feet for energy of rising air: 4.57 X 0.16 X 10.26 = 7.50 +foot pounds per second, which is seen to be still a little +too small, but well within the limits of error, in view of +the hollow shape of the bird's wings, which receive +greater pressure than the flat planes experimented upon +by Langley. + +These computations were chiefly made in January, +1899, and were communicated to a few friends, who found +no fallacy in them, but thought that few aviators would +understand them if published. They were then submitted +to Professor C. F. Marvin of the Weather Bureau, who +is well known as a skillful physicist and mathematician. +He wrote that they were, theoretically, entirely sound +and quantitatively, probably, as accurate as the present +state of the measurements of wind pressures permitted. +The writer determined, however, to withhold publication +until the feat of soaring flight had been performed by +man, partly because he believed that, to ensure safety, it +would be necessary that the machine should be equipped +with a motor in order to supplement any deficiency in +wind force. + +Conditions Unfavorable for Wrights. + +The feat would have been attempted in 1902 by Wright +brothers if the local circumstances had been more favorable. +They were experimenting on "Kill Devil Hill," +near Kitty Hawk, N. C. This sand hill, about 100 feet +high, is bordered by a smooth beach on the side whence +come the sea breezes, but has marshy ground at the back. +Wright brothers were apprehensive that if they rose on +the ascending current of air at the front and began to +circle like the birds, they might be carried by the +descending current past the back of the hill and land in +the marsh. Their gliding machine offered no greater +head resistance in proportion than the buzzard, and their gliding +angles of descent are practically as favorable, but +the birds performed higher up in the air than they. + +Langley's Idea of Aviation. + +Professor Langley said in concluding his paper upon +"The Internal Work of the Wind": + +"The final application of these principles to the art of +aerodromics seems, then, to be, that while it is not likely +that the perfected aerodrome will ever be able to dispense +altogether with the ability to rely at intervals on +some internal source of power, it will not be indispensable +that this aerodrome of the future shall, in order to +go any distance--even to circumnavigate the globe without +alighting--need to carry a weight of fuel which +would enable it to perform this journey under conditions +analogous to those of a steamship, but that the fuel and +weight need only be such as to enable it to take care of +itself in exceptional moments of calm." + +Now that dynamic flying machines have been evolved +and are being brought under control, it seems to be +worth while to make these computations and the succeeding +explanations known, so that some bold man will +attempt the feat of soaring like a bird. The theory +underlying the performance in a rising wind is not new, +it has been suggested by Penaud and others, but it has +attracted little attention because the exact data and the +maneuvers required were not known and the feat had +not yet been performed by a man. The puzzle has always +been to account for the observed act in very light +winds, and it is hoped that by the present selection of +the most difficult case to explain--i. e., the soaring in a +dead horizontal calm--somebody will attempt the exploit. + +Requisites for Soaring Flights. + +The following are deemed to be the requisites and +maneuvers to master the secrets of soaring flight: + +1st--Develop a dynamic flying machine weighing +about one pound per square foot of area, with stable +equilibrium and under perfect control, capable of gliding +by gravity at angles of one in ten (5 3/4 degrees) in still air. + +2nd.--Select locations where soaring birds abound and +occasions where rising trends of gentle winds are frequent +and to be relied on. + +3rd.--Obtain an initial velocity of at least 25 feet per +second before attempting to soar. + +4th.--So locate the center of gravity that the apparatus +shall assume a negative angle, fore and aft, of about 3 degrees. + +Calculations show, however, that sufficient propelling +force may still exist at 0 degrees, but disappears entirely at ++4 degrees. + +5th.--Circle like the bird. Simultaneously with the +steering, incline the apparatus to the side toward which +it is desired to turn, so that the centrifugal force shall +be balanced by the centripetal force. The amount of the +required inclination depends upon the speed and on the +radius of the circle swept over. + +6th.--Rise spirally like the bird. Steer with the +horizontal rudder, so as to descend slightly when going +with the wind and to ascend when going against the +wind. The bird circles over one spot because the rising +trends of wind are generally confined to small areas or +local chimneys, as pointed out by Sir H. Maxim and +others. + +7th.--Once altitude is gained, progress may be made +in any direction by gliding downward by gravity. + +The bird's flying apparatus and skill are as yet infinitely +superior to those of man, but there are indications that +within a few years the latter may evolve more accurately +proportioned apparatus and obtain absolute control over +it. + +It is hoped, therefore, that if there be found no radical +error in the above computations, they will carry the conviction +that soaring flight is not inaccessible to man, as +it promises great economies of motive power in favorable +localities of rising winds. + +The writer will be grateful to experts who may point +out any mistake committed in data or calculations, and +will furnish additional information to any aviator who +may wish to attempt the feat of soaring. + + + +CHAPTER XXI. + +FLYING MACHINES VS. BALLOONS. + +While wonderful success has attended the development +of the dirigible (steerable) balloon the most ardent +advocates of this form of aerial navigation admit that it +has serious drawbacks. Some of these may be described +as follows: + +Expense and Other Items. + +Great Initial Expense.--The modern dirigible balloon +costs a fortune. The Zeppelin, for instance, costs more +than $100,000 (these are official figures). + +Expense of Inflation.--Gas evaporates rapidly, and a +balloon must be re-inflated, or partially re-inflated, every +time it is used. The Zeppelin holds 460,000 cubic feet +of gas which, even at $1 per thousand, would cost $460. + +Difficulty of Obtaining Gas.--If a balloon suddenly +becomes deflated, by accident or atmospheric conditions, +far from a source of gas supply, it is practically worthless. +Gas must be piped to it, or the balloon carted to +the gas house--an expensive proceeding in either event. + +Lack of Speed and Control. + +Lack of Speed.--Under the most favorable conditions +the maximum speed of a balloon is 30 miles an hour. +Its great bulk makes the high speed attained by flying +machines impossible. + +Difficulty of Control.--While the modern dirigible balloon is +readily handled in calm or light winds, its bulk +makes it difficult to control in heavy winds. + +The Element of Danger.--Numerous balloons have +been destroyed by lightning and similar causes. One of +the largest of the Zeppelins was thus lost at Stuttgart +in 1908. + +Some Balloon Performances. + +It is only a matter of fairness to state that, under +favorable conditions, some very creditable records have +been made with modern balloons, viz: + +November 23d, 1907, the French dirigible Patrie, travelled +187 miles in 6 hours and 45 minutes against a +light wind. This was a little over 28 miles an hour. + +The Clement-Bayard, another French machine, sold +to the Russian government, made a trip of 125 miles at +a rate of 27 miles an hour. + +Zeppelin No. 3, carrying eight passengers, and having +a total lifting capacity of 5,500 pounds of ballast in +addition to passengers, weight of equipment, etc., was +tested in October, 1906, and made 67 miles in 2 hours +and 17 minutes, about 30 miles an hour. + +These are the best balloon trips on record, and show +forcefully the limitations of speed, the greatest being not +over 30 miles an hour. + +Speed of Flying Machines. + +Opposed to the balloon performances we have flying +machine trips (of authentic records) as follows: + +Bleriot--monoplane--in 1908--52 miles an hour. + +Delagrange--June 22, 1908--10 1/2 miles in 16 minutes, +approximately 42 miles an hour. + +Wrights--October, 1905--the machine was then in its +infancy--24 miles in 38 minutes, approximately 44 miles +an hour. On December 31, 1908, the Wrights made 77 +miles in 2 hours and 20 minutes. + +Lambert, a pupil of the Wrights, and using a Wright +biplane, on October 18, 1909, covered 29.82 miles in 49 +minutes and 39 seconds, being at the rate of 36 miles +an hour. This flight was made at a height of 1,312 feet. + +Latham--October 21, 1909--made a short flight, about +11 minutes, in the teeth of a 40 mile gale, at Blackpool, +Eng. He used an Antoniette monoplane, and the official +report says: "This exhibition of nerve, daring and ability +is unparalled in the history of aviation." + +Farman--October 20, 1909--was in the air for 1 hour, +32 min., 16 seconds, travelling 47 miles, 1,184 yards, a +duration record for England. + +Paulhan--January 18, 1901--47 1/2 miles at the rate of +45 miles an hour, maintaining an altitude of from 1,000 +to 2,000 feet. + +Expense of Producing Gas. + +Gas is indispensable in the operation of dirigible balloons, +and gas is expensive. Besides this it is not always +possible to obtain it in sufficient quantities even in large +cities, as the supply on hand is generally needed for +regular customers. Such as can be had is either water +or coal gas, neither of which is as efficient in lifting +power as hydrogen. + +Hydrogen is the lightest and consequently the most +buoyant of all known gases. It is secured commercially +by treating zinc or iron with dilute sulphuric or +hydrochloric acid. The average cost may be safely placed +at $10 per 1,000 feet so that, to inflate a balloon of the +size of the Zeppelin, holding 460,000 cubic feet, would +cost $4,600. + +Proportions of Materials Required. + +In making hydrogen gas it is customary to allow 20 +per cent for loss between the generation and the introduction +of the gas into the balloon. Thus, while the +formula calls for iron 28 times heavier than the weight +of the hydrogen required, and acid 49 times heavier, the +real quantities are 20 per cent greater. Hydrogen weighs +about 0.09 ounce to the cubic foot. Consequently if we +need say 450,000 cubic feet of gas we must have 2,531.25 +pounds in weight. To produce this, allowing for the 20 +percent loss, we must have 35 times its weight in iron, +or over 44 tons. Of acid it would take 60 times the +weight of the gas, or nearly 76 tons. + +In Time of Emergency. + +These figures are appalling, and under ordinary conditions +would be prohibitive, but there are times when +the balloon operator, unable to obtain water or coal gas, +must foot the bills. In military maneuvers, where the +field of operation is fixed, it is possible to furnish supplies +of hydrogen gas in portable cylinders, but on long +trips where sudden leakage or other cause makes descent +in an unexpected spot unavoidable, it becomes a question +of making your own hydrogen gas or deserting the balloon. +And when this occurs the balloonist is up against +another serious proposition--can he find the necessary +zinc or iron? Can he get the acid? + +Balloons for Commercial Use. + +Despite all this the balloon has its uses. If there is to +be such a thing as aerial navigation in a commercial +way--the carrying of freight and passengers--it will +come through the employment of such monster balloons +as Count Zeppelin is building. But even then the carrying +capacity must of necessity be limited. The latest +Zeppelin creation, a monster in size, is 450 feet long, +and 42 1/2 feet in diameter. The dimensions are such as +to make all other balloons look like pigmies; even many +ocean-going steamers are much smaller, and yet its passenger +capacity is very small. On its 36-hour flight in +May, 1909, the Zeppelin, carried only eight passengers. +The speed, however, was quite respectable, 850 miles +being covered in the 36 hours, a trifle over 23 miles an +hour. The reserve buoyancy, that is the total lifting +capacity aside from the weight of the airship and its +equipment, is estimated at three tons. + + + +CHAPTER XXII. + +PROBLEMS OF AERIAL FLIGHT. + +In a lecture before the Royal Society of Arts, reported +in Engineering, F. W. Lanchester took the position that +practical flight was not the abstract question which some +apparently considered it to be, but a problem in locomotive +engineering. The flying machine was a locomotive +appliance, designed not merely to lift a weight, +but to transport it elsewhere, a fact which should be +sufficiently obvious. Nevertheless one of the leading scientific +men of the day advocated a type in which this, the +main function of the flying machine, was overlooked. +When the machine was considered as a method of transport, +the vertical screw type, or helicopter, became at +once ridiculous. It had, nevertheless, many advocates +who had some vague and ill-defined notion of subsequent +motion through the air after the weight was raised. + +Helicopter Type Useless. + +When efficiency of transport was demanded, the helicopter +type was entirely out of court. Almost all of +its advocates neglected the effect of the motion of the +machine through the air on the efficiency of the vertical +screws. They either assumed that the motion was +so slow as not to matter, or that a patch of still air +accompanied the machine in its flight. Only one form of this +type had any possibility of success. In this there were +two screws running on inclined axles--one on each side +of the weight to be lifted. The action of such inclined +screw was curious, and in a previous lecture he had +pointed out that it was almost exactly the same as that +of a bird's wing. In high-speed racing craft such inclined +screws were of necessity often used, but it was +at a sacrifice of their efficiency. In any case the efficiency +of the inclined-screw helicopter could not compare +with that of an aeroplane, and that type might be +dismissed from consideration so soon as efficiency became +the ruling factor of the design. + +Must Compete With Locomotive. + +To justify itself the aeroplane must compete, in some +regard or other, with other locomotive appliances, performing +one or more of the purposes of locomotion more +efficiently than existing systems. It would be no use +unless able to stem air currents, so that its velocity must +he greater than that of the worst winds liable to be encountered. +To illustrate the limitations imposed on the +motion of an aeroplane by wind velocity, Mr. Lanchester +gave the diagrams shown in Figs. 1 to 4. The circle +in each case was, he said, described with a radius equal +to the speed of the aeroplane in still air, from a center +placed "down-wind" from the aeroplane by an amount +equal to the velocity of the wind. + +Fig. 1 therefore represented the case in which the +air was still, and in this case the aeroplane represented +by _A_ had perfect liberty of movement in any direction + +In Fig. 2 the velocity of the wind was half that of the +aeroplane, and the latter could still navigate in any +direction, but its speed against the wind was only one- +third of its speed with the wind. + +In Fig. 3 the velocity of the wind was equal to that +of the aeroplane, and then motion against the wind was +impossible; but it could move to any point of the +circle, but not to any point lying to the left of the tangent +_A_ _B_. Finally, when the wind had a greater +speed than the aeroplane, as in Fig. 4, the machine could +move only in directions limited by the tangents _A_ _C_ +and _A_ _D_. + +Matter of Fuel Consumption. + +Taking the case in which the wind had a speed equal +to half that of the aeroplane, Mr. Lanchester said that +for a given journey out and home, down wind and back, +the aeroplane would require 30 per cent more fuel than +if the trip were made in still air; while if the journey +was made at right angles to the direction of the wind +the fuel needed would be 15 per cent more than in a +calm. This 30 per cent extra was quite a heavy enough +addition to the fuel; and to secure even this figure it +was necessary that the aeroplane should have a speed of +twice that of the maximum wind in which it was desired +to operate the machine. Again, as stated in the last +lecture, to insure the automatic stability of the machine +it was necessary that the aeroplane speed should be +largely in excess of that of the gusts of wind liable to +be encountered. + +Eccentricities of the Wind. + +There was, Mr. Lanchester said, a loose connection +between the average velocity of the wind and the maximum +speed of the gusts. When the average speed of +the wind was 40 miles per hour, that of the gusts might +be equal or more. At one moment there might be a +calm or the direction of the wind even reversed, followed, +the next moment, by a violent gust. About the same +minimum speed was desirable for security against gusts +as was demanded by other considerations. Sixty miles +an hour was the least figure desirable in an aeroplane, +and this should be exceeded as much as possible. Actually, +the Wright machine had a speed of 38 miles per +hour, while Farman's Voisin machine flew at 45 miles +per hour. + +Both machines were extremely sensitive to high winds, +and the speaker, in spite of newspaper reports to the +contrary, had never seen either flown in more than a +gentle breeze. The damping out of the oscillations of +the flight path, discussed in the last lecture, increased +with the fourth power of the natural velocity of flight, +and rapid damping formed the easiest, and sometimes +the only, defense against dangerous oscillations. A +machine just stable at 35 miles per hour would have +reasonably rapid damping if its speed were increased to +60 miles per hour. + +Thinks Use Is Limited. + +It was, the lecturer proceeded, inconceivable that any +very extended use should be made of the aeroplane unless +the speed was much greater than that of the motor car. +It might in special cases be of service, apart from this +increase of speed, as in the exploration of countries +destitute of roads, but it would have no general utility. +With an automobile averaging 25 to 35 miles per hour, +almost any part of Europe, Russia excepted, was attainable +in a day's journey. A flying machine of but +equal speed would have no advantages, but if the speed +could be raised to 90 or 100 miles per hour, the whole +continent of Europe would become a playground, every +part being within a daylight flight of Berlin. Further, +some marine craft now had speeds of 40 miles per hour, +and efficiently to follow up and report movements of +such vessels an aeroplane should travel at 60 miles per +hour at least. Hence from all points of view appeared +the imperative desirability of very high velocities of +flight. The difficulties of achievement were, however, +great. + +Weight of Lightest Motors. + +As shown in the first lecture of his course, the resistance +to motion was nearly independent of the velocity, +so that the total work done in transporting a given +weight was nearly constant. Hence the question of fuel +economy was not a bar to high velocities of flight, though +should these become excessive, the body resistance might +constitute a large proportion of the total. The horsepower +required varied as the velocity, so the factor governing +the maximum velocity of flight was the horsepower +that could be developed on a given weight. At +present the weight per horsepower of feather-weight +motors appeared to range from 2 1/4 pounds up to 7 +pounds per brake horsepower, some actual figures being +as follows: + +Antoinette........ 5 lbs. +Fiat.............. 3 lbs. +Gnome....... Under 3 lbs. +Metallurgic....... 8 lbs. +Renault........... 7 lbs. +Wright.............6 lbs. + +Automobile engines, on the other hand, commonly +weighed 12 pounds to 13 pounds per brake horsepower. + +For short flights fuel economy was of less importance +than a saving in the weight of the engine. For long +flights, however, the case was different. Thus, if the +gasolene consumption was 1/2 pound per horsepower hour, +and the engine weighed 3 pounds per brake horsepower, +the fuel needed for a six-hour flight would weigh as much +as the engine, but for half an hour's flight its weight +would be unimportant. + +Best Means of Propulsion. + +The best method of propulsion was by the screw, +which acting in air was subject to much the same conditions +as obtained in marine work. Its efficiency depended +on its diameter and pitch and on its position, +whether in front of or behind the body propelled. From +this theory of dynamic support, Mr. Lanchester proceeded, +the efficiency of each element of a screw propeller +could be represented by curves such as were given +in his first lecture before the society, and from these +curves the over-all efficiency of any proposed propeller +could be computed, by mere inspection, with a fair degree +of accuracy. These curves showed that the tips of +long-bladed propellers were inefficient, as was also the +portion of the blade near the root. In actual marine +practice the blade from boss to tip was commonly of +such a length that the over-all efficiency was 95 per cent +of that of the most efficient element of it. + +Advocates Propellers in Rear. + +From these curves the diameter and appropriate pitch +of a screw could be calculated, and the number of +revolutions was then fixed. Thus, for a speed of 80 feet +per second the pitch might come out as 8 feet, in which +case the revolutions would be 600 per minute, which +might, however, be too low for the motor. It was then +necessary either to gear down the propeller, as was done +in the Wright machine, or, if it was decided to drive it +direct, to sacrifice some of the efficiency of the propeller. +An analogous case arose in the application of the steam +turbine to the propulsion of cargo boats, a problem as +yet unsolved. The propeller should always be aft, so +that it could abstract energy from the wake current, and +also so that its wash was clear of the body propelled. +The best possible efficiency was about 70 per cent, and +it was safe to rely upon 66 per cent. + +Benefits of Soaring Flight. + +There was, Mr. Lanchester proceeded, some possibility +of the aeronaut reducing the power needed for transport +by his adopting the principle of soaring flight, as +exemplified by some birds. There were, he continued, two +different modes of soaring flight. In the one the bird +made use of the upward current of air often to be found +in the neighborhood of steep vertical cliffs. These cliffs +deflected the air upward long before it actually reached +the cliff, a whole region below being thus the seat of +an upward current. Darwin has noted that the condor +was only to be found in the neighborhood of such cliffs. +Along the south coast also the gulls made frequent use +of the up currents due to the nearly perpendicular chalk +cliffs along the shore. + +In the tropics up currents were also caused by +temperature differences. Cumulus clouds, moreover, were +nearly always the terminations of such up currents of +heated air, which, on cooling by expansion in the upper +regions, deposited their moisture as fog. These clouds +might, perhaps, prove useful in the future in showing +the aeronaut where up currents were to he found. An- +other mode of soaring flight was that adopted by the +albatross, which took advantage of the fact that the air +moved in pulsations, into which the bird fitted itself, +being thus able to extract energy from the wind. +Whether it would be possible for the aeronaut to employ +a similar method must be left to the future to decide. + +Main Difficulties in Aviation. + +In practical flight difficulties arose in starting and in +alighting. There was a lower limit to the speed at +which the machine was stable, and it was inadvisable to +leave the ground till this limit was attained. Similarly, +in alighting it was inexpedient to reduce the speed below +the limit of stability. This fact constituted a difficulty +in the adoption of high speeds, since the length of run +needed increased in proportion to the square of the +velocity. This drawback could, however, be surmounted +by forming starting and alighting grounds of ample size. +He thought it quite likely in the future that such grounds +would be considered as essential to the flying machine +as a seaport was to an ocean-going steamer or as a road +was to the automobile. + +Requisites of Flying Machine. + +Flying machines were commonly divided into monoplanes +and biplanes, according as they had one or two +supporting surfaces. The distinction was not, however, +fundamental. To get the requisite strength some form +of girder framework was necessary, and it was a mere +question of convenience whether the supporting surface +was arranged along both the top and the bottom of this +girder, or along the bottom only. The framework adopted +universally was of wood braced by ties of pianoforte +wire, an arrangement giving the stiffness desired with +the least possible weight. Some kind of chassis was also +necessary. + + + +CHAPTER XXIII. + +AMATEURS MAY USE WRIGHT PATENTS. + +Owing to the fact that the Wright brothers have enjoined +a number of professional aviators from using +their system of control, amateurs have been slow to +adopt it. They recognize its merits, and would like to +use the system, but have been apprehensive that it +might involve them in litigation. There is no danger +of this, as will be seen by the following statement made +by the Wrights: + +What Wright Brothers Say. + +"Any amateur, any professional who is not exhibiting +for money, is at liberty to use our patented devices. +We shall be glad to have them do so, and there will be +no interference on our part, by legal action, or otherwise. +The only men we proceed against are those who, without +our permission, without even asking our consent, +coolly appropriate the results of our labors and use them +for the purpose of making money. Curtiss, Delagrange, +Voisin, and all the rest of them who have used our +devices have done so in money-making exhibitions. So +long as there is any money to be made by the use of the +products of our brains, we propose to have it ourselves. +It is the only way in which we can get any return for +the years of patient work we have given to the problem +of aviation. On the other hand, any man who wants +to use these devices for the purpose of pleasure, or the +advancement of science, is welcome to do so, without +money and without price. This is fair enough, is it not?" + +Basis of the Wright Patents. + +In a flying machine a normally flat aeroplane having +lateral marginal portions capable of movement to different +positions above or below the normal plane of the +body of the aeroplane, such movement being about an +axis transverse to the line of flight, whereby said lateral +marginal portions may be moved to different angles relatively +to the normal plane of the body of the aeroplane, +so as to present to the atmosphere different angles +of incidence, and means for so moving said lateral marginal +portions, substantially as described. + +Application of vertical struts near the ends having +flexible joints. + +Means for simultaneously imparting such movement +to said lateral portions to different angles relatively to +each other. + +Refers to the movement of the lateral portions on the +same side to the same angle. + +Means for simultaneously moving vertical rudder so +as to present to the wind that side thereof nearest the +side of the aeroplane having the smallest angle of incidence. + +Lateral stability is obtained by warping the end wings +by moving the lever at the right hand of the operator, +connection being made by wires from the lever to the +wing tips. The rudder may also be curved or warped in +similar manner by lever action. + +Wrights Obtain an Injunction. + +In January, 1910, Judge Hazel, of the United States +Circuit Court, granted a preliminary injunction restraining +the Herring-Curtiss Co., and Glenn H. Curtiss, from +manufacturing, selling, or using for exhibition purposes +the machine known as the Curtiss aeroplane. The injunction +was obtained on the ground that the Curtiss +machine is an infringement upon the Wright patents in +the matter of wing warping and rudder control. + +It is not the purpose of the authors to discuss the +subject pro or con. Such discussion would have no proper +place in a volume of this kind. It is enough to say that +Curtiss stoutly insists that his machine is not an +infringement of the Wright patents, although Judge Hazel +evidently thinks differently. + +What the Judge Said. + +In granting the preliminary injunction the judge said: + +"Defendants claim generally that the difference in +construction of their apparatus causes the equilibrium or +lateral balance to be maintained and its aerial movement +secured upon an entirely different principle from that +of complainant; the defendants' aeroplanes are curved, +firmly attached to the stanchions and hence are incapable +of twisting or turning in any direction; that the +supplementary planes or so-called rudders are secured to +the forward stanchion at the extreme lateral ends of +the planes and are adjusted midway between the upper +and lower planes with the margins extending beyond the +edges; that in moving the supplementary planes equal +and uniform angles of incidence are presented as +distinguished from fluctuating angles of incidence. Such +claimed functional effects, however, are strongly +contradicted by the expert witness for complainant. + +Similar to Plan of Wrights. + +"Upon this contention it is sufficient to say that the +affidavits for the complainant so clearly define the +principle of operation of the flying machines in question +that I am reasonably satisfied that there is a variableness +of the angle of incidence in the machine of defendants +which is produced when a supplementary plane on one +side is tilted or raised and the other stimultaneously +tilted or lowered. I am also satisfied that the rear +rudder is turned by the operator to the side having the +least angle of incidence and that such turning is done +at the time the supplementary planes are raised +or depressed to prevent tilting or upsetting the machine. +On the papers presented I incline to the view, as already +indicated, that the claims of the patent in suit should be +broadly construed; and when given such construction, +the elements of the Wright machine are found in defendants' +machine performing the same functional result. +There are dissimilarities in the defendants' structure-- +changes of form and strengthening of parts--which may +be improvements, but such dissimilarities seem to me to +have no bearing upon the means adopted to preserve the +equilibrium, which means are the equivalent of the claims +in suit and attain an identical result. + +Variance From Patent Immaterial. + +"Defendants further contend that the curved or arched +surfaces of the Wright aeroplanes in commercial use are +departures from the patent, which describes 'substantially +flat surfaces,' and that such a construction would +be wholly impracticable. The drawing, Fig. 3, however, +attached to the specification, shows a curved line inward +of the aeroplane with straight lateral edges, and considering +such drawing with the terminology of the specification, +the slight arching of the surface is not thought +a material departure; at any rate, the patent in issue +does not belong to the class of patents which requires +narrowing to the details of construction." + +"June Bug" First Infringement. + +Referring to the matter of priority, the judge said: + +"Indeed, no one interfered with the rights of the +patentees by constructing machines similar to theirs until +in July, 1908, when Curtiss exhibited a flying machine +which he called the 'June Bug.' He was immediately +notified by the patentees that such machine with its +movable surfaces at the tips of wings infringed the patent +in suit, and he replied that he did not intend to publicly +exhibit the machine for profit, but merely was engaged +in exhibiting it for scientific purposes as a member +of the Aerial Experiment Association. To this the patentees +did not object. Subsequently, however, the machine, +with supplementary planes placed midway between +the upper and lower aeroplanes, was publicly exhibited +by the defendant corporation and used by Curtiss in +aerial flights for prizes and emoluments. It further appears +that the defendants now threaten to continue such +use for gain and profit, and to engage in the manufacture +and sale of such infringing machines, thereby becoming +an active rival of complainant in the business of +constructing flying machines embodying the claims in suit, +but such use of the infringing machines it is the duty +of this court, on the papers presented, to enjoin. + +"The requirements in patent causes for the issuance +of an injunction pendente lite--the validity of the patent, +general acquiescence by the public and infringement +by the defendants--are so reasonably clear that I believe +if not probable the complainant may succeed at final +hearing, and therefore, status quo should be preserved +and a preliminary injunction granted. + +"So ordered." + +Points Claimed By Curtiss. + +That the Herring-Curtiss Co. will appeal is a certainty. +Mr. Emerson R. Newell, counsel for the company, +states its case as follows: + +"The Curtiss machine has two main supporting surfaces, +both of which are curved * * * and are absolutely +rigid at all times and cannot be moved, warped or +distorted in any manner. The front horizontal rudder is +used for the steering up or down, and the rear vertical +rudder is used only for steering to the right or left, in +the same manner as a boat is steered by its rudder. The +machine is provided at the rear with a fixed horizontal +surface, which is not present in the machine of the patent, +and which has a distinct advantage in the operation +of defendants' machine, as will be hereafter discussed. + +Does Not Warp Main Surface. + +"Defendants' machine does not use the warping of the +main supporting surfaces in restoring the lateral equilibrium, +but has two comparatively small pivoted balancing +surfaces or rudders. When one end of the machine +is tipped up or down from the normal, these planes may +be thrown in opposite directions by the operator, and +so steer each end of the machine up or down to its +normal level, at which time tension upon them is released +and they are moved back by the pressure of the +wind to their normal position. + +Rudder Used Only For Steering. + +"When defendants' balancing surfaces are moved they +present equal angles of incidence to the normal rush +of air and equal resistances, at each side of the machine, +and there is therefore no tendency to turn around a +vertical axis as is the case of the machine of the patent, +consequently no reason or necessity for turning the vertical +rear rudder in defendants' machine to counteract any +such turning tendency. At any rate, whatever may be +the theories in regard to this matter, the fact is that +the operator of defendants' machine does not at any +time turn his vertical rudder to counteract any turning +tendency clue to the side balancing surfaces, but only +uses it to steer the machine the same as a boat is +steered." + +Aero Club Recognizes Wrights. + +The Aero Club of America has officially recognized +the Wright patents. This course was taken following a +conference held April 9th, 1910, participated in by William +Wright and Andrew Freedman, representing the +Wright Co., and the Aero Club's committee, of Philip +T. Dodge, W. W. Miller, L. L. Gillespie, Wm. H. Page +and Cortlandt F. Bishop. + +At this meeting arrangements were made by which +the Aero Club recognizes the Wright patents and will +not give its section to any open meet where the promoters +thereof have not secured a license from the +Wright Company. + +The substance of the agreement was that the Aero +Club of America recognizes the rights of the owners of +the Wright patents under the decisions of the Federal +courts and refuses to countenance the infringement of +those patents as long as these decisions remain in force. + +In the meantime, in order to encourage aviation, both +at home and abroad, and in order to permit foreign +aviators to take part in aviation contests in this country +it was agreed that the Aero Club of America, as the +American representative of the International Aeronautic +Federation, should approve only such public contests +as may be licensed by the Wright Company and that +the Wright Company, on the other hand, should encourage +the holding of open meets or contests where ever approved as +aforesaid by the Aero Club of America +by granting licenses to promoters who make satisfactory +arrangements with the company for its compensation +for the use of its patents. At such licensed meet any +machine of any make may participate freely without +securing any further license or permit. The details and +terms of all meets will be arranged by the committee +having in charge the interests of both organizations. + + + +CHAPTER XXIV. + +HINTS ON PROPELLER CONSTRUCTION. + +Every professional aviator has his own ideas as to the +design of the propeller, one of the most important features +of flying-machine construction. While in many +instances the propeller, at a casual glance, may appear +to be identical, close inspection will develop the fact that +in nearly every case some individual idea of the designer +has been incorporated. Thus, two propellers of the two- +bladed variety, while of the same general size as to +length and width of blade, will vary greatly as to pitch +and "twist" or curvature. + +What the Designers Seek. + +Every designer is seeking for the same result--the +securing of the greatest possible thrust, or air displacement, +with the least possible energy. + +The angles of any screw propeller blade having a +uniform or true pitch change gradually for every increased +diameter. In order to give a reasonably clear +explanation, it will be well to review in a primary way +some of the definitions or terms used in connection with +and applied to screw propellers. + +Terms in General Use. + +Pitch.--The term "pitch," as applied to a screw propeller, +is the theoretical distance through which it would +travel without slip in one revolution, and as applied to +a propeller blade it is the angle at which the blades are +set so as to enable them to travel in a spiral path through +a fixed distance theoretically without slip in one revolution. + +Pitch speed.--The term "pitch speed" of a screw +propeller is the speed in feet multiplied by the number of +revolutions it is caused to make in one minute of time. +If a screw propeller is revolved 600 times per minute, +and if its pitch is 7 ft., then the pitch speed of such a +propeller would be 7x600 revolutions, or 4200 ft. per +minute. + +Uniform pitch.--A true pitch screw propeller is one +having its blades formed in such a manner as to enable +all of its useful portions, from the portion nearest the +hub to its outer portion, to travel at a uniform pitch +speed. Or, in other words, the pitch is uniform when the +projected area of the blade is parallel along its full +length and at the same time representing a true sector +of a circle. + +All screw propellers having a pitch equal to their +diameters have the same angle for their blades at their +largest diameter. + +When Pitch Is Not Uniform. + +A screw propeller not having a uniform pitch, but +having the same angle for all portions of its blades, or +some arbitrary angle not a true pitch, is distinguished +from one having a true pitch in the variation of the pitch +speeds that the various portions of its blades are forced +to travel through while traveling at its maximum pitch +speed. + +On this subject Mr. R. W. Jamieson says in Aeronautics: + +"Take for example an 8-foot screw propeller having an +8-foot pitch at its largest diameter. If the angle is the +same throughout its entire blade length, then all the porions +of its blades approaching the hub from its outer portion would +have a gradually decreasing pitch. The 2-foot +portion would have a 2-foot pitch; the 3-foot portion a 3- +foot pitch, and so on to the 8-foot portion which would +have an 8-foot pitch. When this form of propeller is +caused to revolve, say 500 r.p.m., the 8-foot portion would +have a calculated pitch speed of 8 feet by 500 revolutions, +or 4,000 feet per min.; while the 2-foot portion would +have a calculated pitch speed of 500 revolutions by 2 feet, +or 1,000 feet per minute. + +Effect of Non-Uniformity. + +"Now, as all of the portions of this type of screw +propeller must travel at some pitch speed, which must have +for its maximum a pitch speed in feet below the calculated +pitch speed of the largest diameter, it follows that +some portions of its blades would perform useful work +while the action of the other portions would be negative +--resisting the forward motion of the portions having a +greater pitch speed. The portions having a pitch speed +below that at which the screw is traveling cease to perform +useful work after their pitch speed has been exceeded +by the portions having a larger diameter and a +greater pitch speed. + +"We might compare the larger and smaller diameter +portions of this form of screw propeller, to two power- +driven vessels connected with a line, one capable of traveling +20 miles per hour, the other 10 miles per hour. It +can be readily understood that the boat capable of traveling +10 miles per hour would have no useful effect to +help the one traveling 20 miles per hour, as its action +would be such as to impose a dead load upon the latter's +progress." + +The term "slip," as applied to a screw propeller, is the +distance between its calculated pitch speed and the actual +distance it travels through under load, depending upon +the efficiency and proportion of its blades and the amount +of load it has to carry. + +The action of a screw propeller while performing useful +work might be compared to a nut traveling on a +threaded bolt; little resistance is offered to its forward +motion while it spins freely without load, but give it a +load to carry; then it will take more power to keep up its +speed; if too great a load is applied the thread will strip, +and so it is with a screw propeller gliding spirally on the +air. A propeller traveling without load on to new air +might be compared to the nut traveling freely on the bolt. +It would consume but little power and it would travel at +nearly its calculated pitch speed, but give it work to do +and then it will take power to drive it. + +There is a reaction caused from the propeller projecting +air backward when it slips, which, together with the supporting +effect of the blades, combine to produce useful +work or pull on the object to be carried. + +A screw propeller working under load approaches more +closely to its maximum efficiency as it carries its load +with a minimum amount of slip, or nearing its calculated +pitch speed. + +Why Blades Are Curved. + +It has been pointed out by experiment that certain +forms of curved surfaces as applied to aeroplanes will lift +more per horse power, per unit of square foot, while on +the other hand it has been shown that a flat surface will +lift more per horse power, but requires more area of surface +to do it. + +As a true pitch screw propeller is virtually a rotating +aeroplane, a curved surface may be advantageously employed +when the limit of size prevents using large plane +surfaces for the blades. + +Care should be exercised in keeping the chord of any +curve to be used for the blades at the proper pitch angle, +and in all cases propeller blades should be made rigid so +as to preserve the true angle and not be distorted by +centrifugal force or from any other cause, as flexibility +will seriously affect their pitch speed and otherwise affect +their efficiency. + +How to Determine Angle. + +To find the angle for the proper pitch at any point in +the diameter of a propeller, determine the circumference +by multiplying the diameter by 3.1416, which represent +by drawing a line to scale in feet. At the end of this line +draw another line to represent the desired pitch in feet. +Then draw a line from the point representing the desired +pitch in feet to the beginning of the circumference line. +For example: + +If the propeller to be laid out is 7 feet in diameter, and +is to have a 7-foot pitch, the circumference will be 21.99 +feet. Draw a diagram representing the circumference +line and pitch in feet. If this diagram is wrapped around +a cylinder the angle line will represent a true thread 7 +feet in diameter and 7 feet long, and the angle of the +thread will be 17 3/4 degrees. + +Relation of Diameter to Circumference. + +Since the areas of circles decrease as the diameter +lessens, it follows that if a propeller is to travel at a uniform +pitch speed, the volume of its blade displacement +should decrease as its diameter becomes less, so as to +occupy a corresponding relation to the circumferences of +larger diameters, and at the same time the projected +area of the blade must be parallel along its full length +and should represent a true sector of a circle. + +Let us suppose a 7-foot circle to be divided into 20 +sectors, one of which represents a propeller blade. If the +pitch is to be 7 feet, then the greatest depth of the angle +would be 1/20 part of the pitch, or 4 2/10 inch. If the +line representing the greatest depth of the angle is kept +the same width as it approaches the hub, the pitch will +be uniform. If the blade is set at an angle so its projected +area is 1/20 part of the pitch, and if it is moved +through 20 divisions for one revolution, it would have a +travel of 7 feet. + + + +CHAPTER XXV. + +NEW MOTORS AND DEVICES. + +Since the first edition of this book was printed, early in 1910, +there has been a remarkable advance in the construction of +aeroplane motors, which has resulted in a wonderful decrease +in the amount of surface area from that formerly required. +Marked gain in lightness and speed of the motor has enabled +aviators to get along, in some instances, with one-quarter of +the plane supporting area previously used. The first Wright +biplane, propelled by a motor of 25 h.p., productive of a fair +average speed of 30 miles an hour, had a plane surface of 538 +square feet. Now, by using a specially designed motor of 65 +h. p., capable of developing a speed of from 70 to 80 miles an +hour, the Wrights are enabled to successfully navigate a machine +the plane area of which is about 130 square feet. This +apparatus is intended to carry only one person (the operator). +At Belmont Park, N. Y., the Wrights demonstrated that the +small-surfaced biplane is much faster, easier to manage in the +hands of a skilled manipulator, and a better altitude climber +than the large and cumbersome machines with 538 square feet +of surface heretofore used by them. + +In this may be found a practical illustration of the principle +that increased speed permits of a reduction in plane area in +mathematical ratio to the gain in speed. The faster any object +can be made to move through the air, the less will be the +supporting +surface required to sustain a given weight. But, there +is a limit beyond which the plane surface cannot be reduced +with safety. Regard must always be had to the securing of +an ample sustaining surface so that in case of motor stoppage +there will be sufficient buoyancy to enable the operator to +descend safely. + +The baby Wright used at the Belmont Park (N. Y.) aviation +meet in the fall of 1910, had a plane length of 19 feet 6 inches, +and an extreme breadth of 21 feet 6 inches, with a total surface +area of 146 square feet. It was equipped with a new Wright +8-cylinder motor of 60 h. p., and two Wright propellers of 8 +feet 6 inches diameter and 500 r. p. m. It was easily the fastest +machine at the meet. After the tests, Wilbur Wright said: + +"It is our intention to put together a machine with specially +designed propellers, specially designed gears and a motor which +will give us 65 horsepower at least. We will then be able, +after some experimental work we are doing now, to send forth +a machine that will make a new speed record." + +In the new Wright machines the front elevating planes for +up-and-down control have been eliminated, and the movements +of the apparatus are now regulated solely by the rear, or +"tail" +control. + +A Powerful Light Motor. + +Another successful American aviation motor is the aeromotor, +manufactured by the Detroit Aeronautic Construction. +Aeromotors are made in four models as follows: + +Model 1.--4-cylinder, 30-40 h. p., weight 200 pounds. + +Model 2.--4-cylinder, (larger stroke and bore) 40-50 h. p., +weight 225 pounds. + +Model 3.--6-cylinder. 50-60 h. p., weight 210 pounds. + +Model 4.--6-cylinder, 60-75 h. p., weight 275 pounds. + +This motor is of the 4-cycle, vertical, water-cooled type. +Roberts Aviation Motor. + +One of the successful aviation motors of American make, is +that produced by the Roberts Motor Co., of Sandusky, Ohio. +It is designed by E. W. Roberts, M. E., who was formerly +chief assistant and designer for Sir Hiram Maxim, when the +latter was making his celebrated aeronautical experiments in +England in 1894-95. This motor is made in both the 4- and +6-cylinder forms. The 4-cylinder motor weighs complete with +Bosch magneto and carbureter 165 pounds, and will develop +40 actual brake h. p. at 1,000 r. p. m., 46 h. p. at 1,200 and 52 +h. p. at 1,400. The 6-cylinder weighs 220 pounds and will +develop 60 actual brake h. p. at 1,000 r. p. m., 69 h. p. at +1,200 and 78 h. p. at 1,500. + +Extreme lightness has been secured by doing away with all +superfluous parts, rather than by a shaving down of materials +to a dangerous thinness. For example, there is neither an intake +or exhaust manifold on the motor. The distributing valve +forms a part of the crankcase as does the water intake, and +the gear pump. Magnalium takes the place of aluminum in +the crankcase, because it is not only lighter but stronger and +can be cast very thin. The crankshaft is 2 1/2-inch diameter +with a 2 1/4-inch hole, and while it would be strong enough in +ordinary 40 per cent carbon steel it is made of steel twice the +strength of that customarily employed. Similar care has been +exercised on other parts and the result is a motor weighing 4 +pounds per h. p. + +The Rinek Motor. + +The Rinek aviation motor, constructed by the Rinek Aero +Mfg. Co., of Easton, Pa., is another that is meeting with favor +among aviators. Type B-8 is an 8-cylinder motor, the cylinders +being set at right angles, on a V-shaped crank case. It is water +cooled, develops 50-60 h. p., the minimum at 1,220 r. p. m., and +weighs 280 pounds with all accessories. Type B-4, a 4-cylinder +motor, develops 30 h. p. at 1,800 r. p. m., and weighs 130 pounds +complete. The cylinders in both motors are made of cast iron +with copper water jackets. + +The Overhead Camshaft Boulevard. + +The overhead camshaft Boulevard is still another form of +aviation motor which has been favorably received. This is +the product of the Boulevard Engine Co., of St. Louis. It is +made with 4 and 8 cylinders. The former develops 30-35 h. p. +at 1,200 r. p. m., and weighs 130 pounds. The 8-cylinder motor +gives 60-70 h. p. at 1,200 r. p. m., and weighs 200 pounds. +Simplicity of construction is the main feature of this motor, +especially in the manipulation of the valves. + + + +CHAPTER XXVI. + +MONOPLANES, TRIPLANES, MULTIPLANES. + +Until recently, American aviators had not given serious +attention to any form of flying machines aside from biplanes. +Of the twenty-one monoplanes competing at the International +meet at Belmont Park, N. Y., in November, 1910, only three +makes were handled by Americans. Moissant and Drexel +navigated Bleriot machines, Harkness an Antoinette, and +Glenn Curtiss a single decker of his own construction. On +the other hand the various foreign aviators who took part in +the meet unhesitatingly gave preference to monoplanes. + +Whatever may have been the cause of this seeming prejudice +against the monoplane on the part of American air sailors, +it is slowly being overcome. When a man like Curtiss, who +has attained great success with biplanes, gives serious attention +to the monoplane form of construction and goes so far as +to build and successfully operate a single surface machine, +it may be taken for granted that the monoplane is a fixture in +this country. + +Dimensions of Monoplanes. + +The makes, dimensions and equipment of the various monoplanes +used at Belmont Park are as follows: + +Bleriot--(Moissant, operator)--plane length 23 feet, extreme +breadth 28 feet, surface area 160 square feet, 7-cylinder, 50 h. +p. +Gnome engine, Chauviere propeller, 7 feet 6 inches diameter, +1,200 r. p. m. + +Bleriot--(Drexel, operator)--exactly the same as Moissant's +machine. + +Antoinette--(Harkness, operator)--plane length 42 feet, +extreme breadth 46 feet, surface area 377 square feet, Emerson +6-cylinder, 50 h. p. motor, Antoinette propeller, 7 feet 6 inches +diameter, 1,200 r. p. m. + +Curtiss--(Glenn H. Curtiss, operator)--plane length 25 feet, +extreme breadth 26 feet, surface area 130 square feet, Curtiss +8-cylinder, 60 h. p. motor, Paragon propeller, 7 feet in +diameter, 1,200 r. p. m. + +With one exception Curtiss had the smallest machine of +any of those entering into competition. The smallest was La +Demoiselle, made by Santos-Dumont, the proportions of which +were: plane length 20 feet, extreme breadth 18 feet, surface +area 100 square feet, Clement-Bayard 2-cylinder, 30 h. p. motor, +Chauviere propeller, 6 feet 6 inches in diameter, 1,100 r. p. m. + +Winnings Made with Monoplanes. + +Operators of monoplanes won a fair share of the cash prizes. +They won $30,283 out of a total of $63,250, to say nothing about +Grahame-White's winnings. The latter won $13,600, but part +of his winning flights were made in a Bleriot monoplane, and +part in a Farman machine. Aside from Grahame-White the +winnings were divided as follows: Moissant (Bleriot) $13,350; +Latham (Antoinette) $8,183; Aubrun (Bleriot) $2,400; +De Lesseps (Bleriot) $2,300; Drexel (Bleriot) $1,700; Radley +(Bleriot) $1,300; Simon (Bleriot) $750; Andemars (Clement- +Bayard) $100; Barrier (Bleriot) $100. + +Out of a total of $30,283, operators of Bleriot machines won +$21,900, again omitting Grahame-White's share. If the winnings +with monoplane and biplane could be divided so as to +show the amount won with each type of machine the credit +side of the Bleriot account would be materially enlarged. + +The Most Popular Monoplanes. + +While the number of successful monoplanes is increasing +rapidly, and there is some feature of advantage in nearly all +the new makes, interest centers chiefly in the Santos-Dumont, +Antoinette and Bleriot machines. This is because more has +been accomplished with them than with any of the others, +possibly because they have had greater opportunities. + +For the guidance of those who may wish to build a machine +of the monoplane type after the Santos-Dumont or Bleriot +models, the following details will be found useful. + +Santos-Dumont--The latest production of this maker is +called the "No. 20 Baby." It is of 18 feet spread, and 20 feet +over all in depth. It stands 4 feet 2 inches in height, not +counting the propeller. When this latter is in a vertical +position +the extreme height of the machine is 7 feet 5 inches. It +is strictly a one-man apparatus. The total surface area is 115 +square feet. The total weight of the monoplane with engine +and propeller is 352 pounds. Santos-Dumont weighs 110 +pounds, so the entire weight carried while in flight is 462 +pounds, or about 3.6 pounds per square foot of surface. + +Bamboo is used in the construction of the body frame, and +also for the frame of the tail. The body frame consists of +three bamboo poles about 2 inches in diameter at the forward +end and tapering to about 1 inch at the rear. These poles are +jointed with brass sockets near the rear of the main plane so +they may be taken apart easily for convenience in housing or +transportation. The main plane is built upon four transverse +spars of ash, set at a slight dihedral angle, two being placed on +each side of the central bamboo. These spars are about 2 inches +wide by 1 1/8-inch deep for a few feet each side of the center of +the machine, and from there taper down to an inch in depth +at the center bamboo, and at their outer ends, but the width +remains the same throughout their entire length. The planes +are double surfaced with silk and laced above and below the +bamboo ribs which run fore and aft under the main spars and +terminate in a forked clip through which a wire is strung for +lacing on the silk. The tail consists of a horizontal and +vertical +surface placed on a universal joint about 10 feet back of +the rear edge of the main plane. Both of these surfaces are +flat and consist of a silk covering stretched upon bamboo ribs. +The horizontal surface is 6 feet 5 inches across, and 4 feet 9 +inches from front to back. The vertical surface is of the same +width (6 feet 5 inches) but is only 3 feet 7 inches from front +to back. All the details of construction are shown in the +accompanying illustration. + +Power is furnished by a very light (110 pounds) Darracq +motor, of the double-opposed-cylinder type. It has a bore of +4.118 inches, and stroke of 4.724 inches, runs at 1,800 r. p. m., +and with a 6 1/2-foot propeller develops a thrust of 242 1/2 +pounds +when the monoplane is held steady. + +Bleriot--No. XI, the latest of the Bleriot productions, and +the greatest record maker of the lot, is 28 feet in spread of +main +plane, and depth of 6 feet in largest part. This would give a +main surface of 168 square feet, but as the ends of the plane +are sharply tapered from the rear, the actual surface is reduced +to 150 square feet. Projecting from the main frame is an +elongated tail (shown in the illustration) which carries the +horizontal and vertical rudders. The former is made in three +sections. The center piece is 6 feet 1 inch in spread, and 2 feet +10 inches in depth, containing 17 square feet of surface. The +end sections, which are made movable for warping purposes, +are each 2 feet 10 inches square, the combined surface area in +the entire horizontal rudder being 33 square feet. The vertical +rudder contains 4 1/2 square feet of surface, making the entire +supporting area 187 1/2 square feet. + +From the outer end of the propeller shaft in front to the extreme +rear edge of the vertical rudder, the machine is 25 feet +deep. Deducting the 6-foot depth of the main plane leaves 19 +feet as the length of the rudder beam and rudders. The motor +equipment consists of a 3-cylinder, air-cooled engine of about +30 h. p. placed at the front end of the body frame, and carrying +on its crankshaft a two-bladed propeller 6 feet 8 inches in +diameter. The engine speed is about 1,250 r. p. m. at which +the propeller develops a thrust of over 200 pounds. + +The Bleriot XI complete weighs 484 pounds, and with +operator and fuel supply ready for a 25- or 30-mile flight, 715 +pounds. One peculiarity of the Bleriot construction is that, +while the ribs of the main plane are curved, there is no +preliminary +bending of the pieces as in other forms of construction. +Bleriot has his rib pieces cut a little longer than required +and, by springing them into place, secures the necessary +curvature. A good view of the Bleriot plane framework is +given on page 63. + +Combined Triplane and Biplane. + +At Norwich, Conn., the Stebbins-Geynet Co., after several +years of experiment, has begun the manufacture of a combination +triplane and biplane machine. The center plane, which is +located about midway between the upper and lower surfaces, +is made removable. The change from triplane to biplane, or +vice versa, may be readily made in a few minutes. The +constructors +claim for this type of air craft a large supporting +surface area with the minimum of dimensions in planes. Although +this machine has only 24-foot spread and is only 26 +feet over all, its total amount of supporting area is 400 square +feet; weight, 600 pounds in flying order, and lifting capacity +approximately 700 pounds more. + +The frame is made entirely of a selected grade of Oregon +spruce, finished down to a smooth surface and varnished. All +struts are fish-shaped and set in aluminum sockets, which are +bolted to top and lower beams with special strong bolts of +small diameter. The middle plane is set inside the six uprights +and held in place by aluminum castings. A flexible twisted +seven-strand wire cable and Stebbins-Geynet turnbuckles are +used for trussing. + +The top plane is in three sections, laced together. It has a +24-foot spread and is 7 feet in depth. The middle plane is in +two sections each of 7 1/2 feet spread and 6 feet in depth. The +center ends of the middle plane sections do not come within +5 feet of joining, this open space being left for the engine. +The bottom plane is of 16 feet spread and 5 feet in depth. It +will thus be seen that the planes overhang one another in depth, +the bottom one being the smallest in this respect. The planes +are set at an angle of 9 degrees, and there is a clear space of 3 +1/2 feet between each, making the total distance from the bottom +to the top plane a trifle over 7 feet. The total supporting +surface in the main planes is 350 square feet. By arranging the +three plane surfaces at an angle as described and varying their +size, the greatest amount of lifting area is secured above the +center of gravity, and the greatest weight carried below. + +The ribs are made of laminated spruce, finished down to +1/2x3/4-inch cross section dimensions, with a curvature of about +1 in 20, and fastened to the beams with special aluminum +castings. +Number 2 Naiad aeroplane cloth is used in covering the +planes, with pockets sewn in for the ribs. + +Two combination elevating rudders are set up well in front, +each having 18 square feet of supporting area. These rudders +are arranged to work in unison, independently, or in opposite +directions. In the Model B machine, there are also two small +rear elevating rudders, which work in unison with the front +rudders. One vertical rudder of 10 square feet is suspended +in the rear of a small stationary horizontal plane in Model A, +while the vertical rudder on Model B is only 6 square feet in +size. The elevating rudders are arranged so as to act as +stabilizing +planes when the machine is in flight. The wing tips are +held in place with a special two-piece casting which forms a +hinge, and makes a quick detachable joint. Wing tips are also +used in balancing. + +Model A is equipped with a Cameron 25-30 h. p., 4-cylinder, +air-cooled motor. On Model B a Holmes rotary 7-cylinder +motor of 4x4-inch bore and stroke is used. + +Positive control is secured by use of the Stebbins-Geynet +"auto-control" system. A pull or push movement operates the +elevating rudders, while the balancing is done by means of +side movements or slight turns. The rear vertical rudder is +manipulated by means of a foot lever. + +New Cody Biplane. + +Among the comparatively new biplanes is one constructed by +Willard F. Cody, of London, Eng., the principal distinctive +feature of which is an automaticcontrol which works independently +of the hand levers. For the other control a long lever +carrying a steering wheel furnishes all the necessary control +movements, there being no footwork at all. The lever is +universally jointed and when moved fore and aft operates the +two ailerons as if they were one; when the shaft is rotated it +moves the tail as a whole. The horizontal tail component is +immovable. When the lever is moved from side to side it works +not only the ailerons and the independent elevators, but also +through a peculiar arrangement, the vertical rear rudder as well. + +The spread of the planes is 46 feet 6 inches and the width 6 +feet 6 inches. The ailerons jut out 1 foot 6 inches on each +side of the machine and are 13 feet 6 inches long. The cross- +shaped tail is supported by an outrigger composed of two long +bamboos and of this the vertical plane is 9 feet by 4 feet, while +the horizontal plane is 8 feet by 4 feet. The over-all length +of the machine is 36 feet. The lifting surface is 857 square +feet. It will weigh, with a pilot, 1,450 pounds. The distance +between the main planes is 8 feet 6 inches, which is a rather +notable feature in this flyer. + +The propeller has a diameter of 11 feet and 2 inches with a +13-foot 6-inch pitch; it is driven at 560 revolutions by a chain, +and the gear reduction between the chain and propeller shaft +is two to one. + +The machine from elevator to tail plane bristles in original +points. The hump in the ribs has been cut away entirely, so +that although the plane is double surfaced, the surfaces are +closest together at a point which approximates the center of +pressure. The plane is practically of two stream-line forms, +of which one is the continuation of the other. This construction, +claims the inventor, will give increased lift, and decreased +head resistance. The trials substantiate this, as the angle of +incidence in flying is only about one in twenty-six. + +The ribs in the main planes are made of strips of silver spruce +one-half by one-half inch, while those in the ailerons are solid +and one-fourth inch thick. In the main planes the fabric is +held down with thin wooden fillets. Cody's planes are noted +for their neatness, rigidity and smoothness. Pegamoid fabric +is used throughout. + +Pressey Automatic Control. + +Another ingenious system of automatic control has been +perfected by Dr. J. B. Pressey, of Newport News, Va. The +aeroplane is equipped with a manually operated, vertical rudder, +(3), at the stern, and a horizontal, manually operated, +front control, (4), in front. At the ends of the main plane, and +about midway between the upper and lower sections thereof, +there are supplemental planes, (5). + +In connection with these supplemental planes (5), there is +employed a gravity influenced weight, the aviator in his seat, +for holding them in a horizontal, or substantially horizontal, +position when the main plane is traveling on an even keel; and +for causing them to tip when the main plane dips laterally, to +port or starboard, the planes (5) having a lifting effect upon +the +depressed end of the main plane, and a depressing effect upon +the lifted end of the main plane, so as to correct such lateral +dip +of the main plane, and restore it to an even keel. To the +forward, +upper edge of planes (5) connection is made by means +of rod (13) to one arm of a bellcrank lever, (14) the latter +being +pivotally mounted upon a fore and aft pin (15), supported from +the main plane; and the other arms of the port and starboard +bellcrank levers (16), are connected by rod (17), which has an +eye (18), for receiving the segmental rod (19), secured to and +projecting from cross bar on seat supporting yoke (7). When, +therefore, the main plane tips downwardly on the starboard +side, the rod (17) will be moved bodily to starboard, and the +starboard balancing plane (5) will be inclined so as to raise its +forward edge and depress its rear edge, while, at the same time, +the port balancing plane (5), will be inclined so as to depress +its forward edge, and raise its rear edge, thereby causing the +starboard balancing plane to exert a lifting effect, and the port +balancing plane to exert a depressing effect upon the main +plane, with the result of restoring the main plane to an even +keel, at which time the balancing planes (5), will have resumed +their normal, horizontal position. + +When the main plane dips downwardly on the port side, a +reverse action takes place, with the like result of restoring the +main plane to an even keel. In order to correct forward and +aft dip of the main plane, fore and aft balancing planes (20) +and (23) are provided. These planes are carried by transverse +rock shafts, which may be pivotally mounted in any suitable +way, upon structures carried by main plane. In the present +instance, the forward balancing plane is pivotally mounted in +extensions (21) of the frame (22) which carries the forward, +manually operated, horizontal ascending and descending plane + +It is absolutely necessary, in making a turn with an aeroplane, +if that turn is to be made in safety, that the main plane shall +be inclined, or "banked," to a degree proportional to the +radius +of the curve and to the speed of the aeroplane. Each different +curve, at the same speed, demands a different inclination, as is +also demanded by each variation in speed in rounding like +curves. This invention gives the desired result with absolute +certainty. + +The Sellers' Multiplane. + +Another innovation is a multiplane, or four-surfaced machine, +built and operated by M. B. Sellers, formerly of Grahn, Ky., +but now located at Norwood, Ga. Aside from the use of four +sustaining surfaces, the novelty in the Sellers machine lies in +the fact that it is operated successfully with an 8 h. p. motor, +which is the smallest yet used in actual flight. In describing +his work, Mr. Sellers says his purpose has been to develop the +efficiency of the surfaces to a point where flight may be +obtained +with the minimum of power and, judging by the results +accomplished, he has succeeded. In a letter written to the +authors of this book, Mr. Sellers says: + +"I dislike having my machine called a quadruplane, because +the number of planes is immaterial; the distinctive feature being +the arrangement of the planes in steps; a better name would +be step aeroplane, or step plane. + +"The machine as patented, comprises two or more planes +arranged in step form, the highest being in front. The machine +I am now using has four planes 3 ft. x 18 ft.; total about 200 +square feet; camber (arch) 1 in 16. + +"The vertical keel is for lateral stability; the rudder for +direction. This is the first machine (so far as I know) to have a +combination of wheels and runners or skids (Oct. 1908). The +wheels rise up automatically when the machine leaves the +ground, so that it may alight on the runners. + +"A Duthirt & Chalmers 2-cylinder opposed, 3 1/8-inch engine +was used first, and several hundred short flights were made. +The engine gave four brake h. p., which was barely sufficient +for continued flight. The aeroplane complete with this engine +weighed 78 pounds. The engine now used is a Bates 3 5/8-inch, +2-cylinder opposed, showing 8 h. p., and apparently giving +plenty of power. The weight of aeroplane with this engine is +now 110 pounds. Owing to poor grounds only short flights +have been made, the longest to date (Dec. 31, 1910) being about +1,000 feet. + +"In building the present machine, my object was to produce a +safe, slow, light, and small h. p. aeroplane, a purpose which I +have accomplished." + + + +CHAPTER XXVII. + +1911 AEROPLANE RECORDS. + +THE WORLD AT LARGE. + +Greatest Speed Per Hour, Whatever Length of Flight, Aviator +Alone--E. Nieuport, Mourmelon, France, June 21, Nieuport Machine, +82.72 miles; with one passenger, E. Nieuport, Moumlelon, France, +June 12, Nieuport Machine, 67.11 miles; with two passengers, E. +Nieuport, Mourmelon, France, March 9, Nieuport Machine, 63.91 +miles; with three passengers, G. Busson, Rheims, France, March +10, Deperdussin Machine, 59.84 miles; with four passengers, G. +Busson, Rheims, France, March 10, Deperdussin Machine, 54.21 +miles. + +Greatest Distance Aviator Alone--G. Fourny, no stops, Buc, +France, September 2, M. Farman Machine, 447.01 miles; E. Helen, +three stops, Etampes, France, September 8, Nieuport Machine, +778.45 miles; with one passenger, Lieut. Bier, Austria, October +2, Etrich Machine, 155.34 miles; with two passengers, Lieut. +Bier, Austria, October 4, Etrich Machine, 69.59 miles; with three +passengers, G. Busson, Rheims, France, March 10, Deperdussin +Machine, 31.06 miles; with four passengers, G. Busson, Rheims, +France, March 10, Deperdussin Machine, 15.99 miles. + +Greatest Duration Aviator Alone--G. Fourny, no stops, Buc, +France, September 2, M. Farman Machine, 11 hours, 1 minute, 29 +seconds, E. Helen, three stops, Etampes, France, September 8, +Nieuport Machine, 14 hours, 7 minutes, 50 seconds, 13 hours, 17 +minutes net time; with one passenger, Suvelack, Johannisthal, +Germany, December 8, 4 hours, 23 minutes; with two passengers, T. +de W. Milling, Nassau Boulevard, New York, September 26, +Burgess-Wright Machine, 1 hour, 54 minutes, 42 3-5 seconds; with +three passengers, Warchalowski, Wiener-Neustadt, Aust., October +30, 45 minutes, 46 seconds; with four passengers, G. Busson, +Rheims, France, March 10, Deperdussin Machine, 17 minutes, 28 1-5 +seconds. + +Greatest Altitude Aviator Alone--Garros, St. Malo, France, +September 4, Bleriot Machine, 13,362 feet; with one passenger, +Prevost, Courcy, France, December 2, 9,840 feet; with two +passengers, Lieut. Bier, Austria, Etrich Machine, 4,010 feet. + +AMERICAN RECORDS. + +Greatest Speed Per Hour, Whatever Length of Flight, Aviator +Alone--A. Leblanc, Belmont Park, N. Y., October 29, Bleriot +Machine, 67.87 miles; with one passenger, C. Grahame-White, +Squantum, Mass., September 4, Nieuport Machine, 63.23 miles; with +two passengers, T. O. M. Sopwith, Chicago, Ill., August 15, +Wright Machine, 34.96 miles. + +Greatest Distance Aviator Alone--St. Croix Johnstone, Mineola, +N. Y., July 27, Moisant (Bleriot Type) Machine, 176.23 miles. + +Greatest Duration Aviator Alone--Howard W. Gill, Kinloch, Mo., +October 19, Wright Machine, 4 hours, 16 minutes, 35 seconds; with +one passenger, G. W. Beatty, Chicago, Ill., August 19, Wright +Machine, 3 hours, 42 minutes, 22 1-5 seconds; with two +passengers, T. de W. Milling, Nassau Boulevard, N. Y., September +26, Burgess-Wright Machine, 1 hour, 54 minutes, 42 3-5 seconds. + +Greatest Altitude Aviator Alone--L. Beachy, Chicago, Ill., August +20, Curtiss Machine, 11,642 feet; with one passenger, C. Grahame- +White, Nassau Boulevard, N. Y., September 30, Nieuport Machine, +3,347 feet. + +Weight Carrying--P. O. Parmelee, Chicago, III., August 19, +Wright Machine, 458 lbs. + +AVIATION DEVELOPMENT. + +The wonderful progress made in the science of aviation +during the year 1911 far surpasses any twelve months' advancement +recorded. The advancement has not been confined to any country or +continent, since every part of the world is taking its part in +aviation history making. + +The rapidly increasing interest in aviation has brought +forth schools for the instruction of flying in both the old and +new world, and licensed air pilots before they receive their +sanctions from the governing aero clubs of their country are +required to pass an extremely trying examination in actual +flights. Exhibition flights and races were common in all +parts of the world during 1911, and touring aviators visited +India, China, Japan, South Africa, Australia and South +America, giving exhibitions and instruction. + +Europe was the scene of a number of cross-country races +in which entries ranging from ten to twenty aviators flew +from city to city around a given circuit, which in some +instances exceeded 1,000 miles in distance. Cross-country +flights with and without passengers became so common that +those of less than two hours' duration attracted little +attention. There were fewer attempts at high altitude soaring, +although the world's record in this department of aviation +was bettered several times. In place of these high flights, the +aviators devoted more attention to speed, duration and +spectacular manoeuvres, which appeared to satisfy the spectators. +The prize money won during 1911 exceeded $1,000,000, but +owing to the increased number of aviators the individual +winnings were not as large as in 1910. + +It is estimated that within the past twelve months more +than 300,000 miles have been covered in aeroplane flights +and more than seven thousand persons, classed either as +aviators or passengers, taken up into the air. The aeroplane +of today ranges through monoplane, biplane, triplane and +even quadraplane, and more than two hundred types of these +machines are in use. + +Aeroplanes are becoming a factor of international commerce. +The records of the Bureau of Statistics show that +more than $50,000 worth of aeroplanes were imported into, +and exported from, the United States in the months of July, +August and September, 1911. The Bureau of Statistics only +began the maintenance of a separate record of this comparatively +new article of commerce with the opening of the fiscal +year 1911-12. + +Two of the prominent developments of 1911 were the +introduction of the hydro-aeroplane and the motorless glider +experiments of the Wright brothers at Killdevil Hills, N. C., +where during the two weeks' experiments numerous flights +with and against the wind were made, culminating in the +establishing of a record by Orville Wright on October 25, +1911, when in a 52-mile per hour blow he reached an elevation +of 225 feet and remained in the air 10 minutes and 34 +seconds. The search for the secret of automatic stability +still continues, and though some remarkable progress has +been made the solution has not yet been reached. + +NOTABLE CROSS-COUNTRY FLIGHTS OF 1911. + +One of the important features of 1911 in aviation was the +rapid increase in the number and distance of cross-country +flights made either for the purpose of exhibition, testing, +instruction or pleasure. Flights between cities in almost every +country of the world became common occurrences. So great +was the number that only those of more than ordinary importance +because of speed, distance or duration are recorded. +The flights of Harry N. Atwood from Boston to Washington +and from St. Louis to New York, and C. P. Rodgers from +New York to Los Angeles were the most important events +of the kind in this country. The St Louis to New York flight +was a distance by air route, 1,266 miles. Duration of flight, +12 days. Net flying time, 28 hours 53 minutes. Average +daily flight, 105.5 miles. Average speed, 43.9 miles per hour. + +Transcontinental Flight of Calbraith P. Rodgers.--All +world records for cross-country flying were broken during +the New York to Los Angeles flight of Calbraith P. Rodgers, +who left Sheepshead Bay, N. Y., on Sunday, September 17, +1911, and completed his flight to the Pacific Coast on Sunday, +November 5, at Pasadena, Cal. Rodgers flew a Wright biplane, +and during his long trip the machine was repeatedly +repaired, so great was the strain of the long journey in the +air. Rodgers is estimated to have covered 4,231 miles, +although the actual route as mapped out was but 4,017 miles. +Elapsed time to Pasadena, Cal., 49 days; actual time in the +air, 4,924 minutes, equivalent to 3 days 10 hours 4 minutes; +average speed approximating 51 miles per hour. Rodgers' +longest flight in one day was from Sanderson to Sierra Blanca, +Texas, on October 28, when he covered 231 miles. On November +12, Rodgers fell at Compton, Cal., and was badly injured, +causing a delay of 28 days. + +European Circuit Race.--Started from Paris on June 18, +1911. Distance, 1,073 miles, via Paris to Liege; Liege to Spa +to Liege; Liege to Utrecht, Holland; Utrecht to Brussels, +Belgium; Brussels to Roubaix; Roubaix to Calais; Calais to +London; London to Calais and Calais to Paris. Three aeronauts +were killed either at the start or shortly after the race +was in progress. They were Capt. Princetau, M. Le Martin +and M. Lendron. Three others were injured by falls. Seven +hundred thousand spectators witnessed the start from the +aviation field at Vincennes, near Paris. There were more +than forty starters, of which eight finished. The winner, Lieut. +Jean Conneau, who flies under the name of "Andre Beaumont," +completed the circuit on July 7; his actual net flying time for +the distance being 58h. 38m. 4-5s. + +Circuit of England Race--1,010 Miles in Five Sections.-- + +Start, July 22. Finish, July 26. Prize, $50,000. Twenty- +eight entries and eighteen starters. Seventeen finished the +first section from Brooklands to Hendon, a distance of twenty +miles. Five reached Edinburgh, the second section, a distance +of 343 miles, and four completed the entire circuit. + +Paris to Madrid Race.--This race was started at the Paris +aviation held at Issy-les-Moulineaux on Sunday, May 21. There +were twenty-one entrants, and fully 300,000 spectators gathered +to witness the initial flight of the aerial races. The race +was divided into three stages as follows: Paris to Angouleme, +248 miles; Angouleme to St. Sebastian, 208 miles, and from +St. Sebastian to Madrid, 386 miles, a total distance of 842 +miles. After three of the entrants had safely left the field, +Aviator Train lost control of his plane, and in falling struck +and killed M. Berteaux, the French Minister of War, and +seriously injured Premier Monis. The accident caused the +withdrawal of all but six of the original entrants, and of these +but one finished. The race called for a flight over the +Pyrenees Mountains, and Vedrines, the winner, had to rise +to a height of more than 7,000 feet to pass the mountain +barrier near Somosierra Pass. Both Vedrines and Gibert, another +competitor, were attacked by eagles during the latter +stages of the flight. Vedrines, who started from Paris on +Monday, May 22, finished the long and perilous race at 8:06 +a. m. Friday, May 26. Vedrines net flying time, all controls +and enforced stops subtracted, was 14h. 55m. 18s. The various +prizes to the winner aggregated $30,000. + +The Paris-Rome-Turin Race.--The conditions of this race +called for a flight between the cities of Paris, Rome and +Turin, covering a distance of 1,300 miles. The aviators were +permitted by the rules to alight whenever and wherever they +desired and the time limit was set from May 28 to June 15. +A prize of $100,000 was offered the winner, but the contest +was never finished, as one after another the aviators dropped +out until Frey fell near Roncigilione, France, breaking both +arms and legs and unofficially ending the contest. There +were twenty-one entries and twelve actual starters. + +International Speed Cup Race.--The third annual international +James Gordon Bennett speed cup race was held at +Eastchurch, England, on July 1, 1911, and for the second +time was won by an American aviator, C. T. Weymann, in a +French racing aeroplane. The distance was 150 kilometres +equivalent to 94 miles, and the winner's time of 1h. 11m. 36s. +showed an average speed of 78.77 miles per hour. The first +race was held in 1909 and was won by Glenn Curtiss, who +flew the twenty kilometres (12.4 miles) in 15 minutes 50 2-5 +seconds at an average speed of 47 miles per hour. In 1910 +the winner was Grahame-White, who covered 100 kilometres +(62 miles) at Belmont Park, L. I., in 60 minutes 47 3-5 seconds, +an average speed of 61.3 miles per hour. In the 1911 +race there were six starters: three from France, two from +Great Britain and one from the United States. + +Milan to Turin to Milan Race.--This race which was +started from Milan, Italy, on October 29, was restricted to +Italian aviators and had six starters. The distance was +approximately 177 miles and won by Manissero in a Bleriot +machine in 3h. 16m. 2 4-5s. + +New York to Philadelphia Race.--The first intercity aeroplane +race ever held in the United States was started from +New York City on August 5, and finished in Philadelphia the +same day. The prize of $5,000 was offered by a commercial +concern with stores in the two cities: Three entrants competed +from the Curtiss Exhibition Company. The distance +was approximately 83 miles and won by L. Beachey in a +Curtiss machine in 1h. 50m. at an average speed of 45 miles +per hour. + +Tri-State Race.--The tri-state race was the feature event +of the Harvard Aviation Society meet held at Squantum, +Mass., August 26 to September 6. It was held Labor Day, +September 4, over a course of 174 miles, from Boston to +Nashua to Worcester to Providence to Boston. Four competitors +started, of which two finished, the winner, E. Ovington, +in a Bleriot machine. Ovington's net flying time, 3h. 6m. +22 1-5s. Winner's prize, $10,000. + +AEROPLANES AND DIRIGIBLE BALLOONS IN WARFARE. + +Wonderful progress has been made in the development of +the aeroplane in this country and in Europe since 1903, and +within the last two or three years the leading powers of the +world have entered upon extensive tests and experiments to +determine its availability and usefulness in land and naval +warfare. + +At the present time all the great powers are building or +purchasing aeroplanes on an extensive scale. They have +established government schools for the instruction of their +army and navy officers and for experimental work. So-called +"Airship Fleets" have been constructed and placed in commission +as auxiliaries to the armies and navies. The fleets +of France and Germany are about equal and are larger by +far than those of any of the other powers. The length of the +dirigibles composing these fleets runs from 150 to 500 feet; +they are equipped with engines of from 50 to 500 horse-power, +with a rate of speed ranging from 20 to 30 miles per hour. +Their approximate range is from 200 to 900 miles; the longest +actual run (made by the Zeppelin II, Germany) is 800 miles. + +A British naval airship, one of the largest yet built, was +completed last summer. It has cost over $200,000, and it was +in course of designing and construction two years. It is 510 +feet long; can carry 22 persons, and has a lift of 21 tons. + +The relative value of the dirigible balloon and the aeroplane +in actual war is yet to be determined. The dirigible +is considered to be the safer, yet several large balloons of this +class in Germany and France have met with disaster, involving +loss of lives. The capacity of the dirigible for longer +flights and its superior facilities for carrying apparatus and +operators for wireless telegraphy are distinct advantages. + +There has not yet been much opportunity to test the airship +in actual warfare. The aeroplane has been used by the +Italians in Tripoli for scouting and reconnoitering and is said +to have justified expectations. On several occasions the Italian +military aviators followed the movements of the enemy, in +one instance as far as forty miles inland. At the time of the +attack by the Turks a skillful aeroplane reconnaissance revealed +the approach of a large Turkish force, believed to be at +the time sixty miles away in the mountains. + +Aeroplanes and airships, as they exist today, would doubtless +render very valuable service in a time of war, both over +land and water, in scouting, reconnoitering, carrying dispatches, +and as some experts believe, in locating submarines +and mines placed by the enemy in channels of exits from ports. +A "coast aeroplane" could fly out 30 or 40 miles from land. +and rising to a great height, descry any hostile ships on the +distant horizon, observe their number, strength, formation and +direction, and return within two hours with a report to obtain +which would require several swift torpedo-boat destroyers +and a much greater time. The question as to whether it +would be practicable to bombard an enemy on land or sea +with explosive bombs dropped or discharged from flying machines +or airships, is one which is much discussed but hardly +yet determined. + +Aeroplanes have been constructed with floats in the place +of runners and several attempts have been made, in some +cases successfully, to light with them on and to rise from the +water. Mr. Curtiss did this at San Francisco, in January, +1911. Attempts have also been made with the aeroplane to +alight on and to take flight from the deck of a warship. Toward +the end of 1910 Aviator Ely flew to land from the +cruiser Birmingham, and in January, 1911, he flew from land +and alighted on the cruiser Pennsylvania. But in these cases +special arrangements were made which would be hardly practicable +in a time of actual war. + +In November, 1911, a test was made at Newport, R. I., by +Lieut. Rodgers, of the navy, of a "hydro-areoplane" as an +auxiliary to a battleship. The idea of the test was to alight +alongside of the ship, hoist the machine aboard, put out to sea +and launch the machine again with the use of a crane. Lieut. +Rodgers came down smoothly alongside the Ohio, his machine +was easily drawn aboard with a crane, and the Ohio steamed +down to the open sea, where it was blowing half a gale. But, +owing to the misjudgment of the ship's headway, one of the +wings of the machine when it struck the water after being +released from the crane, went under the water and was +snapped off. Lieut. Rodgers was convinced that this method +was too risky and that some other must be devised. + + + +CHAPTER XXVIII. + +GLOSSARY OF AERONAUTICAL TERMS. + +Aerodrome.--Literally a machine that runs in the air. +Aerofoil.--The advancing transverse section of an aeroplane. + +Aeroplane.--A flying machine of the glider pattern, +used in contra-distinction to a dirigible balloon. + +Aeronaut.--A person who travels in the air. + +Aerostat.--A machine sustaining weight in the air. A +balloon is an aerostat. + +Aerostatic.--Pertaining to suspension in the air; the +art of aerial navigation. + +Ailerons.--Small stabilizing planes attached to the main +planes to assist in preserving equilibrium. + +Angle of Incidence.--Angle formed by making comparison +with a perpendicular line or body. + +Angle of Inclination.--Angle at which a flying machine +rises. This angle, like that of incidence, is obtained +by comparison with an upright, or perpendicular line. + +Auxiliary Planes.--Minor plane surfaces, used in conjunction +with the main planes for stabilizing purposes. + +Biplane.--A flying-machine of the glider type with two +surface planes. + +Blade Twist.--The angle of twist or curvature on a +propeller blade. + +Cambered.--Curve or arch in plane, or wing from port +to starboard. + +Chassis.--The under framework of a flying machine; the +framework of the lower plane. + +Control.--System by which the rudders and stabilizing +planes are manipulated. + +Dihedral.--Having two sides and set at an angle, like +dihedral planes, or dihedral propeller blades. + +Dirigible.--Obedient to a rudder; something that may +be steered or directed. + +Helicopter.--Flying machine the lifting power of which +is furnished by vertical propellers. + +Lateral Curvature.--Parabolic form in a transverse direction. + +Lateral Equilibrium or Stability.--Maintenance of the +machine on an even keel transversely. If the lateral +equilibrium is perfect the extreme ends of the machine +will be on a dead level. + +Longitudinal Equilibrium or Stability.--Maintenance of +the machine on an even keel from front to rear. + +Monoplane.--Flying machine with one supporting, or +surface plane. + +Multiplane.--Flying machine with more than three surface +planes. + +Ornithopter.--Flying machine with movable bird-like +wings. + +Parabolic Curves.--Having the form of a parabola--a +conic section. + +Pitch of Propeller Blade.--See "Twist." + +Ribs.--The pieces over which the cloth covering is +stretched. + +Spread.--The distance from end to end of the main surface; +the transverse dimension. + +Stanchions.--Upright pieces connecting the upper and +lower frames. + +Struts.--The pieces which hold together longitudinally +the main frame beams. + +Superposed.--Placed one over another. + +Surface Area.--The amount of cloth-covered supporting +surface which furnishes the sustaining quality. + +Sustentation.--Suspension in the air. Power of sustentation; +the quality of sustaining a weight in the air. + +Triplane.--Flying machine with three surface planes. + +Thrust of Propeller.--Power with which the blades displace +the air. + +Width.--The distance from the front to the rear edge +of a flying machine. + +Wind Pressure.--The force exerted by the wind when +a body is moving against it. There is always more +or less wind pressure, even in a calm. + +Wing Tips.--The extreme ends of the main surface +planes. Sometimes these are movable parts of the +main planes, and sometimes separate auxiliary planes. + + + + + +End Project Gutenberg Etext of Flying Machine: Construction and Operation + |