path: root/old/flymc10.txt

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. Russell

May, 1997  [Etext #907]


Project Gutenberg Etext; Flying Machines: Construction/Operation
*****This file should be named flymc10.txt or flymc10.zip******

Corrected EDITIONS of our etexts get a new NUMBER, flymc11.txt.
VERSIONS based on separate sources get new LETTER, flymc10a.txt.


Scanned by Charles Keller with OmniPage Professional OCR software


We are now trying to release all our books one month in advance
of the official release dates, for time for better editing.

Please note:  neither this list nor its contents are final till
midnight of the last day of the month of any such announcement.
The official release date of all Project Gutenberg Etexts is at
Midnight, Central Time, of the last day of the stated month.  A
preliminary version may often be posted for suggestion, comment
and editing by those who wish to do so.  To be sure you have an
up to date first edition [xxxxx10x.xxx] please check file sizes
in the first week of the next month.  Since our ftp program has
a bug in it that scrambles the date [tried to fix and failed] a
look at the file size will have to do, but we will try to see a
new copy has at least one byte more or less.


Information about Project Gutenberg (one page)

We produce about two million dollars for each hour we work.  The
fifty hours is one conservative estimate for how long it we take
to get any etext selected, entered, proofread, edited, copyright
searched and analyzed, the copyright letters written, etc.  This
projected audience is one hundred million readers.  If our value
per text is nominally estimated at one dollar then we produce $2
million dollars per hour this year as we release thirty-two text
files per month:  or 400 more Etexts in 1996 for a total of 800.
If these reach just 10% of the computerized population, then the
total should reach 80 billion Etexts.

The Goal of Project Gutenberg is to Give Away One Trillion Etext
Files by the December 31, 2001.  [10,000 x 100,000,000=Trillion]
This is ten thousand titles each to one hundred million readers,
which is only 10% of the present number of computer users.  2001
should have at least twice as many computer users as that, so it
will require us reaching less than 5% of the users in 2001.


We need your donations more than ever!


All donations should be made to "Project Gutenberg/CMU": and are
tax deductible to the extent allowable by law.  (CMU = Carnegie-
Mellon University).

For these and other matters, please mail to:

Project Gutenberg
P. O. Box  2782
Champaign, IL 61825

When all other email fails try our Executive Director:
Michael S. Hart <hart@pobox.com>

We would prefer to send you this information by email
(Internet, Bitnet, Compuserve, ATTMAIL or MCImail).

******
If you have an FTP program (or emulator), please
FTP directly to the Project Gutenberg archives:
[Mac users, do NOT point and click. . .type]

ftp uiarchive.cso.uiuc.edu
login:  anonymous
password:  your@login
cd etext/etext90 through /etext96
or cd etext/articles [get suggest gut for more information]
dir [to see files]
get or mget [to get files. . .set bin for zip files]
GET INDEX?00.GUT
for a list of books
and
GET NEW GUT for general information
and
MGET GUT* for newsletters.

**Information prepared by the Project Gutenberg legal advisor**
(Three Pages)


***START**THE SMALL PRINT!**FOR PUBLIC DOMAIN ETEXTS**START***
Why is this "Small Print!" statement here?  You know: lawyers.
They tell us you might sue us if there is something wrong with
your copy of this etext, even if you got it for free from
someone other than us, and even if what's wrong is not our
fault.  So, among other things, this "Small Print!" statement
disclaims most of our liability to you.  It also tells you how
you can distribute copies of this etext if you want to.

*BEFORE!* YOU USE OR READ THIS ETEXT
By using or reading any part of this PROJECT GUTENBERG-tm
etext, you indicate that you understand, agree to and accept
this "Small Print!" statement.  If you do not, you can receive
a refund of the money (if any) you paid for this etext by
sending a request within 30 days of receiving it to the person
you got it from.  If you received this etext on a physical
medium (such as a disk), you must return it with your request.

ABOUT PROJECT GUTENBERG-TM ETEXTS
This PROJECT GUTENBERG-tm etext, like most PROJECT GUTENBERG-
tm etexts, is a "public domain" work distributed by Professor
Michael S. Hart through the Project Gutenberg Association at
Carnegie-Mellon University (the "Project").  Among other
things, this means that no one owns a United States copyright
on or for this work, so the Project (and you!) can copy and
distribute it in the United States without permission and
without paying copyright royalties.  Special rules, set forth
below, apply if you wish to copy and distribute this etext
under the Project's "PROJECT GUTENBERG" trademark.

To create these etexts, the Project expends considerable
efforts to identify, transcribe and proofread public domain
works.  Despite these efforts, the Project's etexts and any
medium they may be on may contain "Defects".  Among other
things, Defects may take the form of incomplete, inaccurate or
corrupt data, transcription errors, a copyright or other
intellectual property infringement, a defective or damaged
disk or other etext medium, a computer virus, or computer
codes that damage or cannot be read by your equipment.

LIMITED WARRANTY; DISCLAIMER OF DAMAGES
But for the "Right of Replacement or Refund" described below,
[1] the Project (and any other party you may receive this
etext from as a PROJECT GUTENBERG-tm etext) disclaims all
liability to you for damages, costs and expenses, including
legal fees, and [2] YOU HAVE NO REMEDIES FOR NEGLIGENCE OR
UNDER STRICT LIABILITY, OR FOR BREACH OF WARRANTY OR CONTRACT,
INCLUDING BUT NOT LIMITED TO INDIRECT, CONSEQUENTIAL, PUNITIVE
OR INCIDENTAL DAMAGES, EVEN IF YOU GIVE NOTICE OF THE
POSSIBILITY OF SUCH DAMAGES.

If you discover a Defect in this etext within 90 days of
receiving it, you can receive a refund of the money (if any)
you paid for it by sending an explanatory note within that
time to the person you received it from.  If you received it
on a physical medium, you must return it with your note, and
such person may choose to alternatively give you a replacement
copy.  If you received it electronically, such person may
choose to alternatively give you a second opportunity to
receive it electronically.

THIS ETEXT IS OTHERWISE PROVIDED TO YOU "AS-IS".  NO OTHER
WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, ARE MADE TO YOU AS
TO THE ETEXT OR ANY MEDIUM IT MAY BE ON, INCLUDING BUT NOT
LIMITED TO WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE.

Some states do not allow disclaimers of implied warranties or
the exclusion or limitation of consequential damages, so the
above disclaimers and exclusions may not apply to you, and you
may have other legal rights.

INDEMNITY
You will indemnify and hold the Project, its directors,
officers, members and agents harmless from all liability, cost
and expense, including legal fees, that arise directly or
indirectly from any of the following that you do or cause:
[1] distribution of this etext, [2] alteration, modification,
or addition to the etext, or [3] any Defect.

DISTRIBUTION UNDER "PROJECT GUTENBERG-tm"
You may distribute copies of this etext electronically, or by
disk, book or any other medium if you either delete this
"Small Print!" and all other references to Project Gutenberg,
or:

[1]  Only give exact copies of it.  Among other things, this
     requires that you do not remove, alter or modify the
     etext or this "small print!" statement.  You may however,
     if you wish, distribute this etext in machine readable
     binary, compressed, mark-up, or proprietary form,
     including any form resulting from conversion by word pro-
     cessing or hypertext software, but only so long as
     *EITHER*:

     [*]  The etext, when displayed, is clearly readable, and
          does *not* contain characters other than those
          intended by the author of the work, although tilde
          (~), asterisk (*) and underline (_) characters may
          be used to convey punctuation intended by the
          author, and additional characters may be used to
          indicate hypertext links; OR

     [*]  The etext may be readily converted by the reader at
          no expense into plain ASCII, EBCDIC or equivalent
          form by the program that displays the etext (as is
          the case, for instance, with most word processors);
          OR

     [*]  You provide, or agree to also provide on request at
          no additional cost, fee or expense, a copy of the
          etext in its original plain ASCII form (or in EBCDIC
          or other equivalent proprietary form).

[2]  Honor the etext refund and replacement provisions of this
     "Small Print!" statement.

[3]  Pay a trademark license fee to the Project of 20% of the
     net profits you derive calculated using the method you
     already use to calculate your applicable taxes.  If you
     don't derive profits, no royalty is due.  Royalties are
     payable to "Project Gutenberg Association/Carnegie-Mellon
     University" within the 60 days following each
     date you prepare (or were legally required to prepare)
     your annual (or equivalent periodic) tax return.

WHAT IF YOU *WANT* TO SEND MONEY EVEN IF YOU DON'T HAVE TO?
The Project gratefully accepts contributions in money, time,
scanning machines, OCR software, public domain etexts, royalty
free copyright licenses, and every other sort of contribution
you can think of.  Money should be paid to "Project Gutenberg
Association / Carnegie-Mellon University".

*END*THE SMALL PRINT! FOR PUBLIC DOMAIN ETEXTS*Ver.04.29.93*END*





Scanned by Charles Keller with OmniPage Professional OCR software





Flying Machine: Construction and Operation
W.J. Jackman and Thos. H. 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