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Building And Flying An Aeroplane
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.. meta::
        :PG.Title: Building And Flying An Aeroplane
        :PG.Id: 62973
        :PG.Rights: Public Domain
        :PG.Producer: James Simmons
        :PG.Credits: This file was produced from page images at the Internet Archive.
        :DC.Creator: Charles B. Hayward
        :DC.Title: Building And Flying An Aeroplane
        :DC.Language: en
        :DC.Created: 1912
        :PG.Released: 2020-08-18
        :coverpage: images/CoverImage.jpg

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.. topic:: Transcriber's Note

    This book was transcribed from scans of the original found at the Internet Archive and at Google Books. 
    I have rotated some images. Tables are treated as images. There are two versions of this book: the first contains both parts and
    the second is published as two volumes with Examination Papers at the end of each, which the student would return to the American
    School of Correspondence for credit. I have included these Examination Papers at the end of each part.

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   :alt: Book Cover Image 

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   :alt: TWENTY HORSEPOWER NEUPORT MONOPLANE MAKING A LANDING
   
   TWENTY HORSEPOWER NEUPORT MONOPLANE MAKING A LANDING
   *This Photograph Protected By International Copyright*

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       BUILDING AND FLYING 

       AN AEROPLANE 

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       A PRACTICAL HANDBOOK COVERING THE DESIGN, 

       CONSTRUCTION, AND OPERATION OF 

       AEROPLANES AND GLIDERS 

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       By
 
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       CHARLES B. HAYWARD 

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       MEMBER, THE AERONAUTICAL SOCIETY; MEMBER, SOCIETY OF AUTOMOBILE 

       ENGINEERS; FORMERLY SECRETARY, SOCIETY OF AUTOMOBILE ENGINEERS; 

       FORMERLY ENGINEERING EDITOR, THE AUTOMOBILE 

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       ILLUSTRATED 

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       CHICAGO
 
       AMERICAN SCHOOL OF CORRESPONDENCE 

       1912 

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    Copyright 1912 by

    American School of Correspondence

    Entered at Stationers' Hall, London 

    All Rights Reserved 

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BUILDING AND FLYING AN AEROPLANE
--------------------------------

INTRODUCTION
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The field of aviation has, from the inception of successful flight 
by the Wright Brothers, had a wonderful fascination for the 
amateur mechanic. At first the strong element of mystery in the 
movements of this monster man-ridden bird appalled him, but an 
examination of approved designs has removed the mystery and has 
assured him that he can, with his own hands and at a cost well 
within his reach, build his own machine in his own back yard. 

But in this ease of accomplishment lies a danger, namely, the 
belittling of the value of accurate design and the misjudging of the 
true importance of small things. The inventive mind usually believes 
itself capable of making improvements in almost anything, and 
the aeroplane inventor is no exception to the rule. Filled with the 
confidence born of ignorance, and with only the knowledge he 
has gleaned from newspaper and magazine accounts of the popular 
types of machines, he works out a brand new design. The usual, 
in fact, the invariable result is failure, discouragement, and a loss of 
time and money. How much more sensible for the young inventor 
to build his first machine without varying in one particular from a 
tried and proved model, leaving his flights of inventive fancy to his 
later years of maturer knowledge and judgment. 

The author of this little book has followed, in both biplane 
and monoplane models, the well-known types of Curtiss and Bleriot, 
choosing each as the simplest representative of its class in 
construction and design. It is hoped that the book may not only be of 
assistance to the amateur builder, but may also be the means of turning 
the too confident inventor into safer and more established paths. 

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   :alt: HARRY ATWOOD IN HIS BURGESS HYDROAEROPLANE SKIMMING OVER THE SURFACE OF MARBLEHEAD BAY
   
   HARRY ATWOOD IN HIS BURGESS HYDROAEROPLANE SKIMMING OVER THE SURFACE OF MARBLEHEAD BAY

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PART 1 
``````

One of the commonest phases of interest in aviation is the 
desire to build a flying machine. In fact, this is very frequently 
the first thing the experimenter undertakes after having gone into 
the theory of flight to some extent. Only too often, no effort 
whatever is made to get beyond theory and the machine is an experiment 
in every sense of the word. An experience of this nature is 
costly—far more so than is agreeable for the student, and is likely to 
result in disgusting him with aviation generally. There are hundreds 
of schemes and principles in the art that have been tried again and 
again with the same dismal failure in the end. Refer to the story 
of the Wright Brothers and note how many things they mention 
having tried and rejected as worse than useless. About once in so 
often someone "rediscovers" some of these things and, having no 
facilities for properly investigating what patent attorneys term the 
"prior art" (everything that has gone before, from the beginning of 
invention, or at least patented invention) becomes possessed of 
the idea that he has hit upon something entirely novel and wholly 
original. There is no desire in the present work to discourage the 
seeker after new principles—undoubtedly there are many yet to be 
discovered. The art of flight is in its infancy and there is still a 
great deal to be learned about it, but there is no more discouraged 
inventor than he who-discovers a principle and, after having 
experimented with it at great expense, finds that it is only one of many 
things that numerous others have spent considerable money in 
proving fallacious, a great many years ago. 

If it be your ambition to build a flying machine and you believe 
that you have discovered something new of value, it will be to your 
interest to retain a responsible patent attorney to advise you as to 
the prior art, before expending any money on its construction. You 
will find it very much more economical in the end. There are 
probably not more than half a dozen men alive in this country today 
who "know all the schemes that won't work." The average seeker 
after knowledge is assuredly not likely to be one of these few, so 
that until he knows he is working along new and untried lines that 
give promise of success, it will pay him to stick to those that have 
proved successful in actual practice. In other words, to confine 
his efforts in the building line to a machine that experience has 
demonstrated will fly if properly constructed and, what is of equal 
importance, skilfully handled. Build a machine, by all means, if 
you have the opportunity. It represents the best possible experience. 
But as is pointed out under the "Art of Flying," take a few lessons 
from some one who knows how to fly, before risking your neck in 
what is to you a totally untried element. Even properly designed 
and constructed machines are not always ready to fly. An aeroplane 
needs careful inspection of every part and adjustment before it is 
safe to take to the air in it, and to be of any value this 
looking-over must be carried out by an experienced eye. 

BUILDING AEROPLANE MODELS
#########################

The student may enter upon the business of building to any 
extent that his inclination or his financial resources or his desire to 
experiment may lead him. The simplest stage, of course, is that 
of model building and there is a great deal to be learned from the 
construction and flying of experimental models. This has become 
quite a popular pastime in the public schools and some very 
creditable examples of work have been turned out. The apparent 
limitations of these rubber-band driven models need not discourage the 
student, as some of the school-boy builders have succeeded in 
constructing models capable of flying a quarter mile in still air and their 
action in the air is wonderfully like the full-sized machines. 

**Models with Rubber-Band Motor**. The limitations of the 
available power at command must be borne in mind, as the 
rubber-band motor is at best but a poor power plant. It is accordingly not 
good practice to have the spread of the main planes exceed 24 inches, 
though larger successful models have been built. In attempting to 
reproduce any of the well-known models, difficulty is often 
experienced in accommodating the rubber-band motor to them, as even 
where the necessary space is available, its weight throws the balance 
out entirely, and the result is a model that will not fly. This has led 
to the production of many original creations, but these, while 
excellent flyers, would not serve as models for larger machines, as of 
necessity they have been designed around their power plants. The rubber 
bands for this purpose may be purchased of any aeronautic supply 
house. The most practical method of mounting the motor is to 
attach it to the rear end of the fuselage, usually a single stick, which 
is accordingly made extra long for that purpose. At the other end 
it is attached to a bent wire fastened to the propeller in order to 
revolve the latter. An easy way to wand up the motor is to employ 
an ordinary egg beater, modified as described below, or a hand 
drill, inserting a small wire yoke in the jaws in place of the usual 
drill, or bit. This yoke is placed so as to engage the propeller blades, 
and the latter is then turned in the opposite direction, storing 
energy in the rubber band by twisting its strands tightly. 

.. figure:: images/Image3.jpg
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   :alt: Fig. 1. Details of Main Frame of Rubber-Band Driven Aeroplane Model 
   
   Fig. 1. Details of Main Frame of Rubber-Band Driven Aeroplane Model 

For those students who do not care to undertake an original 
design at the outset, or who would prefer to have the experience 
gained by building from a plan that has already been tried, before 
attempting to originate, the following description of a successful 
model is given. This model can not only be made for less than the 
models sold at three to five dollars, but is a much more efficient flyer, 
having frequently flown 700 feet. 

*Main Frame*. The main frame of the model monoplane 
consists of two strips A of spruce, each 28 inches long, and measuring in 
cross section 1/4 by 3/8 of an inch. As shown in Fig. 1, the two strips 
are tied together at the front with strong thread and are then 
glued, the glue being spread over and between the windings of the 
thread, Figs. 1 and 2. The rear ends of these strips are spread 
apart 4 1/4 inches to form a stout triangular frame, and are tied together 
by cross bars of bamboo B and C which are secured to the main 
strips A by strong thread and glue. 

.. figure:: images/Image4.jpg
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   :alt: Fig. 2. Details of Forward Skids of Aeroplane Model 
   
   Fig. 2. Details of Forward Skids of Aeroplane Model 

*Propellers*. The propellers *D* are two in number and are carried by 
the two long strips *A*. Each propeller is 5 inches in diameter, and 
is whittled out of a single block of white pine. The propellers have 
a pitch of about 10 inches. After the whittling is done they 
are sandpapered and coated with varnish. The thickness of the 
wood at the hub *E₂*, Fig. 3, of the propeller should be about 5/8
inch. At the rear ends of the strips *A*, bearing blocks *E₁* are secured. 
These bearing blocks are simply small pieces of wood projecting 
about 5/8 inch laterally from the strips *A*. They are drilled to 
receive a small metal tube *T₂* (steel, brass, or copper), through which 
tube the propeller shaft *T₁* passes. 

.. figure:: images/Image5.jpg
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   :alt: Fig. 3. Details of Propeller and Rudder of Aeroplane Model 
   
   Fig. 3. Details of Propeller and Rudder of Aeroplane Model 

The propeller shaft itself consists of a piece of steel wire passing 
through the propeller hub and bent over the wood, so that it can 
not turn independently of the propeller. Any other expedient for 
causing the propeller to turn with the shaft may obviously be 
employed. Small metal washers *T₃*, at least three in number, are 
slipped over the propeller shaft so as to lie between the propeller 
and the bearing block. 

That portion of the propeller shaft which projects forwardly 
through the bearing block *E₁* is bent to form a hook *T₄*. To the hook *T₁* rubber strips *T₂* by which 
the propellers are driven, are secured. The rubber strips are nearly 
as long as the main strips *A*. At their forward ends they are secured 
to a fastening consisting of a double hook *G H*, the hook *G* lying in 
a horizontal plane, the hook *H* in a vertical plane. The hook holds 
the rubber strips, as shown in Figs. 1 and 4, while the hook *H* 
engages a hook *T*. This hook is easily made by passing a strip of steel 
wire through the meeting ends of the main strips *A*, the portions 
projecting from each side of the strips being bent into the hooks *I*. 

*Skids*. Three skids are provided, on which the model slides, 
one at the forward end, and two near the rear end. All are made 
of bamboo. As shown in Fig. 2 the front skid may be of any length 
that seems desirable. A 6-inch piece of bamboo will probably answer 
most requirements. This piece *N* is bent in opposite directions at 
the ends to form arms *Z* and *U*, The arm *Z* is secured to the forward 
ends of the two strips *A*, constituting the main frame, by means of 
thread and glue. The strips and skid are not held together by the 
same thread, but the skid is attached to the two strips after they have 
been wound. Hence, there are two sets of windings of thread, one 
for the two strips *A* themselves, and another for the skid and the 
strips. Strong thread and glue should be used, as before. In order 
to stiffen the skid, two bamboo struts *W* will be found necessary. 
These are bent over at the ends to form arms *V₁*, Fig. 2. Each of the 
arms is secured to the under side of a strip *A* by strong thread and 
glue. The arms *X* are superimposed and tied to the bamboo skid *V* 
with strong thread and glue. 

.. figure:: images/Image6.jpg
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   :alt: Fig. 4. Details of Rear Skids on Aeroplane Model  
   
   Fig. 4. Details of Rear Skids on Aeroplane Model 

The two rear skids, of which one is shown in Fig. 5, consist each 
of two 5-inch strips of bamboo *S*, likewise bent at either end in opposite 
directions to form arms *S₂* and *S₃*, The arms *S₂* are fastened to the 
strips *A* by strong thread and glue. To stiffen the skids a strut *C₁* is 
provided for each skid. Each strut consists of a 3-inch strip of 
bamboo bent over so as to form arms *C₂*. Strong thread and 
glue are employed to fasten each strut in position on the strip and 
the skid. In the crotch of the triangular space *B₁*, a tie bar *J*, Figs. 
4 and 5, is secured by means of thread and glue. This tie bar 
connects the two skids, as shown in Figs. 1 and 4, and serves to stiffen 
them. The triangular space *B₁* is covered with paper, preferably 
bamboo paper. If bamboo paper is not available, parchment or 
stiff light paper of some kind may be used. It does not need to 
be waterproof. Thus triangular fins are formed which act as 
stabilizing surfaces.

.. figure:: images/Image7.jpg
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   :alt: Fig. 5. Enlarged Details of One Rear Skid, Aeroplane Model 
   
   Fig. 5. Enlarged Details of One Rear Skid, Aeroplane Model 

*Main Planes*. The main planes are two in number, but are 
different in size. Contrary to the practice followed in large 
man-carrying monoplanes, the front supporting surface is comparatively 
small in area and the rear supporting surface comparatively large. 
These supporting surfaces *L* and *P* are shown in detail in Figs. 6 
and 7. It has been found that a surface of considerable area is 
required at the rear of the machine to support it, hence, the 
discrepancy in size. Although the two supporting surfaces differ in 
size, they are made in exactly the same manner, each consisting of 
a thin longitudinal piece of spruce *R*, to which cross pieces of bamboo 
*Q* are attached. In the smaller plane, Fig. 7, all the cross pieces are 
of the same size. In the larger plane, Fig. 6, the outer strips *S* are 
somewhat shorter than the others. Their length is 2 1/2 inches, whereas 
the length of the strips *Q* is 3 1/2 inches. In order to allow for the more 
gradual tapering of the plane, around the outer ends of the 
longitudinal strips *R* and the ribs *Q* a strip of bamboo is tied. The 
frame, composed of the longitudinal strip and cross strips, is then 
covered with bamboo paper, parchment paper, or any other style 
light paper, which is glued in place. 

.. figure:: images/Image8.jpg
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   :alt: Fig. 6. Details of Main Plane of Aeroplane Model
   
   Fig. 6. Details of Main Plane of Aeroplane Model

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   :alt: Fig. 7. Details of Smaller Plane of Aeroplane Model 
   
   Fig. 7. Details of Smaller Plane of Aeroplane Model 

The forward or smaller plane has a spread of 8 1/2 inches and a 
depth of 3 1/4 inches. The main plane has a spread of 20 inches and 
a depth of 3 1/2 inches at the widest portion. The author has made 
experiments which lead him to believe that the tapering form given 
to the outer edge of the plane improves both the stability and 
endurance of the machine. 

The planes are slightly arched, although it will be found that 
flat planes will also give good results. The rear edge of the main 
plane should be placed 4 1/4 inches distant from the forward edge of 
the propeller block *E₁*. 

The front plane must have a slight angle of incidence, just how 
much depends upon the weight of the machine, the manner in which 
it is made, and various other factors. This 
angle of incidence is obtained by resting the 
front portion of the plane on two small blocks 
N, Figs. 1 and 2, which are fastened to the 
top of the main strip *A* by strong thread and 
glue. 

.. figure:: images/Image10.jpg
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   :alt: Fig. 8. Device for Winding up Rubber-Band Motors 
   
   Fig. 8. Device for Winding up Rubber-Band Motors 

The height of the blocks N should be 
about 1/4 inch, although this will necessarily 
vary with the machine. The blocks should 
be placed approximately 4 inches from the 
forward end of the machine. The front end 
of the forward plane should be elevated about 
1/4 inch above the rear end, which rests directly 
on the main strips. 

Both the front and rear planes *L* and *P* 
are removably lashed to the frame by means 
of ordinary rubber bands, which may be obtained at any stationery 
store. These rubber bands are lettered *M* in Fig. 1. 

*Winding the Rubber Strips*. The rubber strips can be most 
conveniently wound up by means of an egg beater, slightly changed 
for the purpose. Fig. 8. The beater and the frame in which it is 
carried are entirely removed, leaving only the main rod *E*, which 
is cut off at the lower end so that the total length is not more than 
2 or 3 inches. The two brass strips *D* on either side of the rod, 
which are attached to the pinion *Q* meshing with the large driving 
wheel *H*, are likewise retained. A washer *F* is soldered to the rod
near its upper end, so as to limit the motion of the small pinion 
and the brass strips *D* attached to the pinion. Next a wire *B* is bent 
in the form of a loop, through which loop the central rod passes. 
The ends of the wire are soldered to the side strips *D*. Lastly, a 
piece of wire *C* is bent and soldered to the lower ends of the side 
strips. In order to wind up a rubber strip, the strip is detached from 
the forward end of the model, and the hook *A* slipped over the wire 
*C*. The opposite end of the rubber band is held in any convenient 
manner. Naturally the two strips must be wound in opposite 
directions, so that the two propellers will turn in opposite directions. 
By stretching the rubber while it is being wound, more revolutions 
can be obtained. It is not safe to have the propeller revolve more 
than 700 times. The ratio of the gears of the egg-beater winder can 
be figured out so that the requisite number of twists can be given 
to the rubber bands for that particular number of revolutions. 

*Model with Gasoline Motor*. The next and somewhat more 
ambitious stage is the building of a power-driven model, which has 
been made possible by the manufacture of miniature gasoline motors 
and propellers for this purpose. Motors of this kind, weighing but 
a few pounds and capable of developing 1/4 horse-power or more, may 
be had complete with an 18-inch aluminum propeller and accessories 
for about $45. As is the case with the rubber-band driven model, 
the monoplane is the simplest type to construct, and the dimensions 
and details of an aeroplane of this type are given here. It will be 
found that a liberal-sized machine is required to support even such 
a small motor. The planes, Fig. 9, have a spread of 7 feet 8 inches 
from tip to tip, each wing measuring 3 1/2 feet by a chord of 15 inches. 
They are supported on a front and rear wing spar of spruce, 1/2 by 
3/8 inch in section, while the ribs in both the main plane and the 
rear stabilizing plane measure 1/8 by 1/2 inch in cross section. There 
are eight of these spruce ribs in the main plane, and they are separately 
heated and curved over a Bunsen burner, or over a gas stove, which 
is the same tiling. They are then nailed to the wing spars 6 inches 
apart. The main spars of the fuselage are 7 feet long and they are 
made of 1/2 by 3/8 inch spruce, the struts being placed 1 1/2 feet apart, 
measuring from the rear, with several intermediate struts to brace 
the engine bed. Instead of using strut sockets for the fuselage, which 
would increase the cost of construction unnecessarily, a simple 
combination of a three-way wire fastener and a wire nail may be resorted 
to. The shape of these fasteners is shown at *A* in Fig. 9. They may 
be cut out of old cracker boxes or tin cans (sheet iron) with a pair 
of shears, the holes in the ends being made either with a small drill 
or by driving a wire nail through the metal placed on a board, and 
filing the burrs off smooth. A central hole must also be made for 
the 1 1/2 inch wire nail which is driven through the main spar and the 
fastener then slipped over it. As indicated, this nail also serves to 
hold the strut. A drop of solder will serve to attach the fastener to 
the nail. The front of the fuselage is 9 inches square, tapering down 
to 6 inches at the rear. The height of the camber of the main planes
is 1 1/2 inches and the angle of incidence is 7 degrees, measured with 
relation to the fuselage. The non-lifting tail plane at the rear which 
is to give the machine longitudinal stability, measures 4 feet in span 
by 14 inches in depth. 

.. figure:: images/Image11.jpg
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   :alt: Fig. 9. Details of Power-Driven Aeroplane Model
   
   Fig. 9. Details of Power-Driven Aeroplane Model

The running gear or front landing frame is made of 1/2 inch 
square spruce, all joints being made with 1/16 by 1 inch bolts. 
Aluminum sleeves, procurable at an aeronautic supply house, are employed 
for the attachment of the rubber springs and the radius rods running 
down to the wheels, which may also be purchased ready to install. 
Old bicycle wheels will serve the purpose admirably. Light steel 
tubes 1/2 inch in diameter are used to run these aluminum sleeves on. 
Two other steel tubes are joined to the lower corner of the frame 
by flattening them at the ends and drilling with a small hole for a 
nail. These are run diagonally up to the fuselage and serve as buffers 
to take the shocks of landing. For bracing the wings, two similar 
tubes are fastened to form a pyramid on top of the main plane just 
back of the engine. From these, guys are run to the wings as shown. 
The engine bed is made of 1/2 by 3/4-inch white pine, and to make it 
solid it is carried as far back as the rear edge of the main plane. The 
batteries and coil are directly attached to this plane, care being 
taken in their placing to preserve the balance of the machine. The 
rudder measures 14 inches square and is made of 3/8-inch square spruce, 
reinforced with tin at the joints, as it is necessary to make the frame 
perfectly rigid. Both sides are covered with fabric. In this case 
a 1-horse-power motor furnishes the necessary energy and it is 
fitted with an 18-inch aluminum propeller which it is capable of 
turning at 2,400 r.p.m. The carbureter and gas tank are made integral, 
and the gasoline and oil are both placed in this tank in the 
proportion of about four parts to one, in order to save the weight of an 
extra tank for oil. 

Flights of half a mile are possible with this model in calm weather, 
but a great deal of measuring and testing of the fuel is necessary in 
order to regulate the flight, and "grass-cutting" should be practiced 
by the builder in order to properly regulate the machine. Trials 
have shown that the flat non-lifting tail on the fuselage gives excellent 
longitudinal stability, the machine rising nicely and making its 
descent very easy angle, so that it is seldom damaged by violent 
collisions in landing. 

BUILDING A GLIDER
#################

The building of hand- or power-driven models does not suffice 
to give that personal experience that most students are desirous of 
obtaining. The best method of securing this is to build a glider 
and practice with it. Any flying machine without a motor is a glider 
and the latter is the basis of the successful aeroplane. In the building 
of an aeroplane the first thing constructed is the glider, *i.e.* the frame, 
main planes, stabilizing planes, elevators, rudders, etc. It is only by 
the installation of motive power that it becomes a flying machine. 
The biplane will be found the most satisfactory type of glider as it
is more compact and therefore more easily handled, which is of great 
importance for practicing in a wind. The generally accepted rule is 
that 152 square feet of surface will sustain the weight of the average 
man, about 170 pounds, and it will be apparent that the length of 
the glider will have to be greater if this surface is to be in the form 
of a single plane than if the same amount is obtained by 
incorporating it in two planes—the biplane. A glider with a span of 20 
feet and a chord of 4 feet will have a surface of 152 square feet. So 
far as learning to balance and guide the machine are concerned, this 
may be mastered more readily in a small glider than in a large one, so 
that there is no advantage in exceeding these dimensions—in fact, 
rather the reverse, as the larger construction would be 
correspondingly more difficult to handle. The materials necessary consist of 
a supply of spruce, linen shoe thread, metal sockets, piano wire, 
turnbuckles, glue, and closely-woven, light cotton fabric for the 
covering of the planes. 

**Main Frame**. The main frame or box cell is made of four 
horizontal beams of spruce 20 feet long and 1 1/2 by 3/4 inch in section. They 
must be straight-grained and perfectly free from knots or other 
defects. If it be impossible to obtain single pieces of this length, 
they may be either spliced or the glider may be built in three sections, 
consisting of a central section 8 feet long, and two end sections each 
6 feet in length, this form of construction also making the glider 
much easier to dismantle and stow in a small space. In this case, 
the ends of the beams of each end section are made to project beyond 
the fabric for 10 inches and are slipped into tubes bolted to corresponding
projections of the central section. These tubes are drilled
with three holes each and bolts are passed through these holes and 
corresponding holes in the projecting ends after they have been 
fitted into the tubes, and drawn up tightly with two nuts on each 
bolt to prevent shaking loose. Ordinary 3/16-inch stove bolts will 
serve very nicely for this purpose. The upper and lower planes 
forming the box cell, are held apart by 12 struts, 4 feet long by 7/8 inch 
diameter, preferably of rounded or oval form with the small edge 
forward to minimize the head resistance. It is only necessary to 
space these equally, starting from both ends; this will bring the 
splices of the demountable sections in the center of the square on 
either side of the central section. The main ribs are 3 feet long by 
1 1/4- by 1/2-inch section and their placing should coincide with the 
position of the struts. Between these main ribs are placed 41 small 
ribs, equally spaced and consisting of pieces 4 feet long by 1/2 inch 
square. These, as well as all the other pieces, should have the sharp 
edges of the square rounded off with sand paper. The ribs should 
have a camber of 2 inches in their length and the simplest method 
of giving them this is to take a piece of plank, draw the desired curve 
on it, and then nail blocks on both sides of this curve, forming a 
simple mould. The rib pieces should then be steamed, bent into this 
mould, and allowed to dry, when they will be found to have 
permanently assumed the desired curvature. Meanwhile, all the 
other pieces may be shellaced and allowed to dry. 

.. figure:: images/Image12.jpg
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   :alt: Fig 10. Wrong and Right way of Making a Wire Joint
   
   Fig 10. Wrong and Right way of Making a Wire Joint

*Assembling the Planes*. To assemble the glider, the beams are 
laid out on a floor, spaced the exact distance apart, *i.e.*, 3 feet, 
and exactly parallel—in the demountable plan, each section is 
assembled independently. The main ribs are then glued in place 
and allowed to set, after which they are strongly bound in place with 
the linen thread, and the various layers of thread given a coating of 
hot glue as they are put on. This method is not arbitrary, but it is 
simple and gives the lightest form of construction. If desired, 
tie-plates, clamps, or any other light method of fastening may be 
employed. This also applies to the ribs. They are assembled by 
placing them flush with the front beam and allowing them to extend 
back a foot beyond the rear beam, arched side up in every case. They 
may be glued and bound with thread, held by clamps, or nailed or 
screwed into place, care being taken to first start a hole in the beam 
with an awl and to dip the nails in soft soap to prevent splitting the 
wood. Twenty-one ribs, spaced one foot apart, are used in the upper 
plane, and 20 in the lower, owing to the space left for the operator in 
the latter. For fastening the two planes together, whether as a 
whole or in sectional units, 24 aluminum sockets will be required. 
These may be purchased either ready to fit, or an effective substitute 
made by sawing short lengths of steel tubing, slitting them with 
the hack saw an inch from the bottom, and then flattening out 
and drilling the right-angle flanges thus formed to take screws for 
attaching the sockets to the beams. In case these sockets are bought, 
they will be provided with eye bolts for the guy wires; if homemade, 
they may have extra holes drilled in the edges of the flanges for this 
purpose or some simple wire fastener such as that described in 
connection with the power-driven model may be used, heavier metal, 
however, being employed to make 
them. The sockets should all be 
screwed to the beams at the 
proper points and then the struts 
should be forced into them. The 
next move is to "tie" the frame 
together with guy wires. No. 12 
piano wire being employed for this 
purpose. Each rectangle is trussed 
by running diagonal guy wires 
from each corner to its opposite. To pull these wires taut, a 
turnbuckle should be inserted in each and after the wire has been pulled 
as tightly as possible by hand, it should be wound upon itself to 
make a good strong joint, as shown at *B*, Fig. 6. A fastening as 
shown at *A* will pull out under comparatively little strain and is not 
safe. As is the case with most of the other fittings, these 
turnbuckles may be bought or made at home, the simple bicycle type of 
turnbuckle mentioned in connection with "Building a Curtiss," 
being admirably adapted to this purpose. In fact, the construction 
of the latter will be found to cover the requirements of the glider, 
except that the ribs are simpler and lighter, as already described, 
and no provision for the engine or similar details is necessary. All 
the guy wires must be tightened until they are rigid, and the proper 
degree of tension for them may be simply determined in the 
following manner: 

After the entire frame is wired, place each end of it on a saw horse 
so as to lift it two or three feet clear of the floor. Stand in the 
opening of the central section, as if about to take a glide, and by grasping 
the forward central struts, raise yourself from the floor so as to bring 
your entire weight upon them. If properly put together the frame 
will be rigid and unyielding, but should it sag even slightly, the guy 
wires must be uniformly tightened until even the faintest perceptible 
tendency to give under the weight is overcome. 

*Stretching the Fabric*. The method of attaching the fabric will 
be determined by whether the glider is to be one piece or sectional, 
and the expense for this important item of material may be as little 
or as much as the builder wishes to make it. Some employ rubberized 
silk, others special aeronautic fabrics, but for the purposes of the 
amateur, ordinary muslin of good quality, treated with a coat of 
light varnish after it is in place, will be found to serve all purposes. 
The cloth should be cut into 4-foot strips, glued to the front horizontal 
beams, stretched back tightly, and tacked to both the rear horizontal 
beams and to the ribs. Tacks should also supplement the glue on 
the forward beams and the upholstery style should be used to 
prevent tearing through the cloth. In case the glider is built in sections, 
the abutting edges of the cloth will have to be reinforced by turning 
it over and stitching down a strip one inch wide, and it will make 
this edge stronger if an extra strip of loose fabric be inserted under 
the turn before sewing it down. Eyelets must then be made along 
these edges and the different sections tightly laced together when 
assembling the glider. It is also desirable to place a strip of cloth or 
light felt along the beams under the tacks to prevent the cloth from 
tearing out under the pressure. 

To form a more comfortable support for the operator, two arm 
pieces of spruce, 3 feet by 1 inch by 1 3/4 inches, should be bolted to 
the front and rear beams about 14 inches apart over the central 
opening left in the lower plane. These will be more convenient than 
holding on to the struts for support, as it will not be necessary to 
spread the arms so much and there will be more freedom for 
manipulating the weight to control the glider in flight. In using the struts, 
it is customary to grasp them with the hands, while with the arm 
pieces, as the name implies, the operator places his arms over them, 
one of the strips coming under each armpit. After the fabric has 
been given a coat of varnish on the upper side and allowed to dry, 
the glider is ready for use. The cost of the material should be about 
$30 to $40, depending upon the extent to which the builder has 
relied upon his own ingenuity in fashioning the necessary 
fittings—in any case, it will be less than the amount required for the purchase 
of the engine alone for a power-driven model. 

**Glider with Rudder and Elevator**. It will be noted that this is 
the simplest possible form of glider in that it is not even provided 
with a rudder, but for the beginning of his gliding education the 
novice will not require this, as first attempts should be confined to 
glides over level ground in moderate, steady wind currents and at a 
modest elevation. Some of the best gliding flights made by Herring, 
Chanute's co-worker, were in a rudderless glider. After having 
mastered the rudiments of the art, the student may go as far as the 
dictates of his ambition impel him in the direction of improvements 
in his glider, by adding a rudder, elevator, and warping control. In 
fact, it is not necessary to confine himself to the simple design of 
glider here outlined at all. He may take either the Wright or Curtiss 
machines as a model and build a complete glider, following the 
dimensions and general methods of construction here given, though 
these may also be improved upon by the man handy with tools, 
bearing in mind that the object to be achieved is the minimum weight 
consistent with the maximum strength. 

**Learning to Glide**. The first trials should be made on level 
ground and the would-be aviator should be assisted by two 
companions to help him in getting under way. The operator takes a 
position in the center rectangle, back far enough to tilt up slightly 
the forward edges of the planes. A start and run forward is made 
at a moderate pace, the keepers carrying the weight of the glider 
and overcoming its head resistance by running forward at the same 
speed. As the glider cuts into the air, the wind caused by running 
will catch under the uplifted edges of the curved planes and will 
buoy it up, causing it to rise in the air taking the operator with 
it. This rise will be probably only sufficient to lift him clear of the 
ground a foot or two. Now he projects his legs slightly forward so as 
to shift the center of gravity a trifle and bring the edges of the glider 
on an exact level, parallel with the ground. This, with the momentum 
acquired at the start, will keep the glider moving forward for some
distance. When the weight of the operator is slightly back of the 
center of gravity, the leading edges of the planes are tilted up 
somewhat, increasing the angle of incidence and in consequence the 
pressure under the planes, causing the glider to rise, and if the glide is 
being made into a wind, as should always be the case, quite a height 
may be reached as the result of this energy. Once it ceases, the 
tendency to a forward and upward movement is lost, and it is to prolong 
this as much as possible that the operator shifts the center of gravity 
to bring the machine on an even keel, or where at a little height, 
slightly below this, giving it a negative angle of incidence, which 
permits him to coast down the air until sufficient speed is acquired 
to reverse the angle of incidence and again rise so as to provide a 
"hill" for another coast, thus prolonging the flight considerably. 
To put it in the simplest language, when the operator moves 
backward, shifting the center of gravity to the rear, the planes are tilted 
so that they catch or "scoop up" the advancing air and rise upon it, 
whereas when he moves forward and the planes tilt downward, this 
air is "spilled" out behind and no longer acts as a support, and the 
glider coasts, either until the ground is reached or enough momentum 
is gained to again mount upon the wind. A comparatively few flights 
will suffice to make the student proficient in the control of his 
apparatus by his body movements, not only as concerns the elevating 
and depressing of the planes to ascend or descend, corresponding 
to the use of the elevator on a power machine, but also actual 
steering, which is accomplished by lateral movement to the left or 
right. 

Stable equilibrium is one of the chief essentials to successful 
flight and this can not be maintained in an uncertain, gusty wind, 
especially by the novice. The beginner should certainly not attempt 
a glide unless the conditions are right. These are a clear, level space 
without obstructions such as trees, and a steady wind not exceeding 
12 miles per hour. When a reasonable amount of proficiency has 
been attained in the handling of the glider over level ground, the 
field of practice may be changed to some gentle slope. In starting 
from this, it will be found easier to keep the glider afloat, but the 
experience at first will prove startling to the amateur, for as the 
glider sails away from the top of the slope, the distance between him 
and the ground increases so rapidly that he will imagine himself at 
a tremendous height, but by preserving the balance and otherwise 
manipulating his weight in the manner taught by the practice over 
the level, a nice flight of much greater distance will be made and the 
machine will gradually settle down to the ground much farther away 
from the starting place than was possible in the earlier trials, this being 
one of the great advantages of starting from an elevation. There is 
nothing that will fit the beginner so well for the actual handling of 
a power machine as a thorough course of gliding flights, and it is 
recommended that those who build gliders become proficient in their 
use before attempting to pilot an aeroplane, whether of their own 
make or not. 

A further step in advance is the actual building of a full-fledged 
power machine, and for those who desire a simple and comparatively 
inexpensive type, requiring very little work that can not be 
performed in the home workshop, a description of the construction of a 
Curtiss biplane is given, while for those who are more ambitious 
and also have greater financial resources, the details of the building 
of a Bleriot monoplane are given. 

BUILDING A CURTISS BIPLANE
##########################

Cost. First of all, the prospective builder will want to know 
the cost. The best answer to this is that the machine will cost all 
its builder can afford to spend upon it and probably a little more, 
as the man to whom the expense is not of vital consideration will 
doubtless not undertake its construction. Speaking generally, and 
there can be nothing very definite about it, in view of the great 
difference in the conditions, an expenditure of three to four hundred 
dollars will cover the complete outlay for everything but the motor. 
If the builder has the time and facilities for doing all the work 
himself, this amount may be reduced very materially. On the other 
hand, if he finds it necessary to purchase most of the material in 
form ready to assemble, it may exceed this. But it will be a great 
aid to many to know that there is practically nothing about the 
modern aeroplane which can not be found in stock at one of the 
aeronautic supply houses. This makes it possible for many to 
undertake the construction of a machine to whom it would not be 
feasible, or at least not an attractive project in view of the time 
involved, were it necessary to make every part at home. So far
as becoming involved in any 
legal difficulties is concerned 
owing to existing patents, 
the student need not worry 
himself about this in 
attempting the construction of 
a Curtiss biplane, so long as 
he restricts the use of his 
machine to experimental 
purposes and does not try to 
compete with the patentees 
in their own field—that of 
exhibiting and selling 
machines. 

.. figure:: images/Image13.jpg
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   :alt: Fig 11. Detailed Front View of Curtiss Biplane
   
   Fig 11. Detailed Front View of Curtiss Biplane

**General Specifications**. Just 
how long it will take to 
complete such a machine will 
depend very largely upon the 
skill of the builder and the 
extent of his resources for, as 
already mentioned, the expense 
may be cut down by making 
all the necessary parts at 
home, but it will naturally be 
at the sacrifice of a great deal 
of time. For instance, the 
oval struts and beams may be 
bought already shaped from 
the local planing mill, or they 
may be shaved down from the 
rough by hand. Turnbuckles 
can be made from bicycle 
spokes and nipples and strips 
of sheet steel, or they can be 
bought at 12 to 15 cents each. 
As a hundred or more of them 
are needed, their cost is quite 
a substantial item. 

.. figure:: images/Image14.jpg
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   :alt: Fig 12. Plan and Side Elevation of Curtiss Biplane
   
   Fig 12. Plan and Side Elevation of Curtiss Biplane

Aeroplane construction doubtless impresses the average observer 
as being something shrouded in considerable mystery—something 
about which there is no little secrecy. Quite the contrary is the case 
in reality. Any man who is fairly proficient as a carpenter and 
knows how to use the more common machinist's tools, such as taps 
and dies, drills, hacksaw, and the like, will find no difficulty in 
constructing the machine of which the details are given here. Having 
completed its building, he will have to draw upon his capital to 
supply the motor. One capable of developing 25 to 30 horse-power 
at 1,000 to 1,200 r.p.m. will give the machine considerable speed, 
as it will be recalled that Curtiss made a number of his first flights
with a 25-horse-power motor. As to the weight, the lighter the 
better, but 400 pounds for the complete power plant will not be 
excessive. The machine can sustain itself in the air with less power 
than that mentioned, but with a heavy, low-power motor it will be 
sluggish in action. This is an advantage for the amateur, rather 
than otherwise, as it will provide him with an aeroplane that will 
not be apt to get away from him during his first trials, thus making 
it safer to learn on. 

.. figure:: images/Image15.jpg
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   :alt: Fig 13. Details of Main and Small Ribs, Curtiss Biplane
   
   Fig 13. Details of Main and Small Ribs, Curtiss Biplane

The Curtiss biplane has a spread of 30 feet, the main planes or 
wings being divided into sections of a length equal to the distance 
between struts, Figs. 11 and 12. There are five of these sections, each 
measuring six feet. The struts can be taken out and the sections 
laid flat on each other for storage. The framework for the front and 
rear rudders can also be jointed, if desired, making it possible to 
store the machine in small compass. The longest parts of the machine, 
when taken apart, are the two diagonal beams running from the 
front wheel back to the engine bed, and the skid. The horizontal 
front rudder is packed intact. The vertical rear rudder is unhung 
and laid flat on the tail. Two men can take the machine apart in 
a few hours, and can reassemble it in a day. Whether these particular 
features of construction are covered by patents can not be said, as 
Curtiss has declined to commit himself regarding any rights he 
may have to them. 

.. figure:: images/Image16.jpg
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   :alt: Table 1. Relative Strength of Clear Spruce and Elm as Demonstrated By Tests
   
*Ribs*. Two distinct types of ribs are used, main ribs and small 
ribs, both of the same curvature, Fig. 13. The main ribs are used 
between pairs of struts, to hold apart the front and rear beams; they 
are heavy enough to be quite rigid. Three to four small ribs are laid 
across each section of the planes, between the pairs of main ribs, to 
give the cloth the proper curvature, and to maintain it in the form 
desired. The main ribs are built up of six 1/4-inch laminations of wood 
7/8 inch wide and securely glued together. The small ribs are made of 
three layers 1/2 inch wide. 

The first part of the actual construction will be the making of 
these laminated ribs, but before describing this detail, the question 
of suitable material should be well considered. Both weight and 
strength must be figured on and this limits the choice to a few kinds 
of wood. Of these *spruce* and *elm* are the best available, with the 
occasional use of *ash* to give greater rigidity. Spruce is, of course, 
the first choice. This wood was once considered as having no 
great strength, but a series of careful tests shows this belief to 
be unfounded. With the exception of the bed, or support for the
motor and a few other parts, the Wright machines are constructed 
wholly of spruce. 

Table I gives results of tests made with spruce from Washington 
and Oregon, and with elm from Michigan and Indiana. Testing 
scales were employed, the pieces being supported at their ends with 
the load in the center. 

These tests were made with clear wood in each case, as knots 
naturally decrease the strength of a piece greatly, this depending on 
their size and location. 

.. figure:: images/Image17.jpg
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   :alt: Fig. 14. Details of Rib Press, Curtiss Biplane
   
   Fig. 14. Details of Rib Press, Curtiss Biplane

Before proceeding with the ribs themselves, the press for giving 
them the proper curvature must be made. Take a good piece of 
oak, ash, or other solid wood, 8 inches wide by 5 feet long, and 
dressed all over. On the side of the piece lay out the curve, the 
dimensions of which are illustrated in Fig. 14. First, rule the 
horizontal, or chord line, on it, marking off 4 feet 6 inches on this line, 
equidistant from each end. Then divide the chord into 6-inch 
sections and, at the point of each 6-inch section, erect perpendiculars 
beginning at the rear, 3/4 inch, 1 3/8 inches, 2 inches, and so on, as 
indicated on the drawing. The upper ends of these perpendiculars will 
form locating points for the curve. Through them draw a smooth 
curve as shown, continuing it down through the chord at each end. 
Take the piece with the curve thus marked on it to the local planing, 
sash and blind, or sawmill—any plant equipped with a band saw—and 
have it cut apart along the curve. This will cost little or 
nothing—acquaintance will obtain it as a favor, and acquaintance with any 
wood-working concern in the aeroplane builder's home town will 
be of great aid. Failing this aid, the operation may be carried out 
with a hand saw (rip), but the job will not be as neat and will have 
to be cleaned up with a draw knife and sand paper, taking care to 
preserve the outline of the curve as drawn. As the rib press is really 
a mould or pattern from which all the ribs are to be bent to a uniform 
curvature, care must be taken in its construction. 

To clamp the two halves of the press together, a dozen machine 
bolts will be required; they should measure 3/4 X 15 inches. If 
obtainable, eye bolts will be found more convenient as they may be turned 
up with but one wrench and a bar. The steel straps are 3/8 by 1 1/2 by 
10 inches long with 3/4-inch holes drilled 9 inches apart to centers, 
to enclose the 8-inch pieces. 

Obtain a sufficient supply of boards of reasonably clear spruce, 
1/4 inch thick, 6 to 7 inches wide, and at least 4 feet 9 inches long 
(dressed both sides), to make all the ribs necessary both small and large. 
This material should be purchased from the mill as it is out of the 
question to attempt to cut the ribs from larger sizes by hand. Buy 
several pounds of good cabinet makers' glue and a water-jacketed 
gluepot. This glue comes in sheets and in numerous grades—a 
good quality should be used, costing from 40 to 50 cents a pound if 
bought in a large city. Laminating the ribs in this manner and 
gluing them together is not only the quickest and easiest method 
of giving them the proper curve, being much superior to steam 
bending, but is also stronger when well done, as the quality of the material 
can be watched more closely. 

Start with the making of the small ribs; apply the glue thin and 
piping hot in a generous layer to three boards with a good-sized flat 
paint or varnish brush. Omit on the upper surface of third board 
and apply between three others, Fig. 13. This will give two series 
of three each in the press. Tighten up the end bolts first, as the 
upper part of the press near the top of the curve is likely to be weak
unless liberally proportioned. Then turn down the nuts on the 
other bolts. Do not attempt to turn any one of them as far as it 
will go the first time, but tighten each one a little at a time, thus 
gradually making the compression over the whole surface as nearly 
uniform as possible. This should be continued until the glue will 
no longer ooze out from between the boards, indicating that they are 
in close contact. Twenty-four hours should be allowed for drying, 
and when taken out the cracks between the boards should be almost 
invisible in the finished ribs. 

Have the laminated boards cut by a power rip saw at the planing 
mill, to the dimensions shown in the drawing, making an allowance 
of 1/4 inch for the width of the saw blade at each cut in calculating 
the number of ribs which can be cut from each board. In addition, 
a margin should be allowed at each side, as it is impractical to get 
all the thin boards squarely in line. For the main ribs, apply the 
glue between all six boards, clamp and dry in the same manner. 
Thirty small ribs will be required, if three are used in each section, 
and forty if four are specified, while twelve main ribs will be needed 
for standard construction, and sixteen if the quick-demountable 
plan referred to is followed. It is advisable to make several extra 
ribs of each kind in addition. If the builder has not sufficient faith 
in spruce alone, despite the figures given in Table I, one of the 
laminations, preferably the center, or if two be employed, the outer 
ones, may be of ash, though this will add considerably to the weight. 

To prevent the ribs from splitting open at the ends, they are 
protected by light steel ferrules, shown in Fig. 15. When received in 
the rough-sawed condition from the mill, the ribs must be tapered 
at the ends with a plane or spoke shave to fit these ferrules, and the 
sharp edges should be rounded off. In doing this, it must be 
remembered that the upper surface of the small ribs gives the curvature 
to the cloth surface, so that any tapering must be done on the lower 
side. The main ribs may be tapered from both sides, as it is the 
center line, or crack between the third and fourth laminations, that 
determines the curve. Every inch along this line A-inch holes are 
to be drilled for the lacing, Fig. 15. 

The ferrules for the front ends of the small ribs are light 1/2-inch 
seamless steel tubing; they may be flattened to the proper shape 
in a vise without heating and are drilled with a 1/8-inch hole. They 
are driven tight on to the tapered ends of the ribs and fastened in 
place with a small screw. The rear-end ferrules are 1/2-inch lengths 
of 3/8-inch tubing, driven on and drilled with a 1/32-inch hole for the 
rear-edge wire. The rear ferrules of the main ribs may be the same 
1/2-inch tubing used for the front of the small ribs; they should be 
cut off so that their ends will come in the same line as the holes in 
the ends of the small ribs. If the quick-demountable plan be 
followed, the second main rib from each end may be left long and 
drilled with a hole like the small ribs. The front ferrules of the 
main ribs should be 3/4-inch tubing of heavier gauge, drilled with a 
1/4-inch hole. The finished ribs are sandpapered smooth and 
shellaced or coated with spar varnish. The latter is much more expensive 
and slower in drying but has the great advantage of being 
weather-proof and will protect the glue cracks from moisture. The ferrules 
may be painted with black enamel. 

.. figure:: images/Image18.jpg
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   :alt: Fig. 15. Details of Ribs and Struts, Curtiss Biplane
   
   Fig. 15. Details of Ribs and Struts, Curtiss Biplane

*Struts*. Before going into the detail of the construction of the 
remainder of the *main cell* and its attached framing, a brief description
of its parts and their relation to one another will make matters 
clearer. The upright struts, Fig. 15, which hold the two planes 
apart, fit at each end into sockets, which are simply metal cups with 
bolts projecting through their ends. Fig. 16. Those at the bottom 
of the front row of struts pass through the eyes of the turnbuckles 
and connections for the wire trussing, then through the flattened 
ferrules of the main ribs, and finally through the beam, all being 
clamped together with a nut. Those at the top go through the 
turnbuckles first, then through the beam, and finally the rib ferrule. 
The bolts at the back row of struts must go through the full 
thickness of the main ribs, and so must be longer. The drawings. Figs. 
15 and 16, show the method of attachment of both the main and 
the small ribs and illustrate a neat method of attaching the 
turnbuckles—instead of being strung on the socket bolt one after another, 
they are riveted to the corners of a steel plate which alone is clamped 
under the socket. 

.. figure:: images/Image19.jpg
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   :alt: Fig. 16. Details of Metal Parts of Curtiss Biplane 
   
   Fig. 16. Details of Metal Parts of Curtiss Biplane 

*Beams*. The beams are jointed at each strut connection, the 
ends being cut square and united by a sheet-steel sleeve, a pattern 
of which is shown in Fig. 16, clamped on by two small bolts. The 
hole for the socket bolt is drilled half in each of the two abutting 
beams. As it is very difficult to obtain long pieces of wood 
sufficiently straight grained and free from knots for the purpose, this 
jointed system considerably cheapens the construction. Both beams 
and struts are of spruce, but to give additional strength, the beams 
of the middle section may be ash. Special aero cloth, rubberized 
fabrics, or light, closely-woven duck (racing yacht sail cloth of fine 
quality, this being employed at first by the Wright Brothers in 
their machines) forms the surfaces of the wings. The front edge of 
each section of the surface is tacked to the beam and the rear edge 
is laced over the rear wire already referred to, this wire being stretched 
taut through the holes in the rear tips of the ribs, both main and 
small. After the cloth is stretched tight, it is tacked to the small 
ribs, a strip of tape being laid under the tack heads to prevent the 
cloth from pulling away from under them. If the aeroplane is intended 
to be taken apart very often, the standard design as shown by the 
large drawings, Figs. 11 and 12, may be modified so as to make it 
unnecessary to unlace the cloth each time. This is arranged by 
regarding the two outer sections at each end of the plane as one, 
and never separating them. Additional main ribs are then 
provided at the inner ends of these sections, and are attached directly 
to the beams, instead of being clamped under the strut sockets. 
In taking the machine apart, the struts are pulled from the sockets, 
leaving the latter in place. It will then be an advantage to shorten 
the main planes somewhat, say 3 inches on each section, so that the 
outer double sections will come under the "12-foot rule" of the Express 
Companies. 

*Running Gear*. Three wheels are provided—one in front under 
the outrigger and two under the main cell for starting and landing. 
Two beams extend from the front wheel to the engine bed and 
serve to carry the pilot's seat, as will be seen from the elevator, 
Fig. 12. A third beam runs back horizontally from the front wheel 
and on rough ground acts as a skid. The rest of the running gear is 
made of steel tubing, the pieces being joined simply by flattening 
the ends, drilling and clamping with bolts; no sockets or special 
connections of any kind are necessary here. If desired, the wheels 
may be carried in bicycle forks and may be fitted with shock absorbers, 
some idea of the various expedients adopted by different builders 
for this purpose being obtainable from the sketches. Fig. 40 in "Types 
of Aeroplanes." Two separate tubes, one on each side of the wheel
make a simple construction and will probably serve just as well. The 
details of the running gear will be given later. 

*Outrigging and Rudders*. For the outriggers and the frames 
carrying the front horizontal or elevating rudder and the rear vertical 
rudder and tail, or horizontal keel, either spruce or bamboo may be 
employed. Bamboo will be found on machines turned out by the 
Curtiss factory, and while it is the lighter of the two, it is not 
generally favored, as spruce is easier to obtain in good quality and is 
far easier to work. At their ends, these outriggers are fitted with 
ferrules of steel tubing, flattened and drilled through. The 
outriggers are attached to the main framework of the machine by 
slipping the ferrules over the socket bolts of the middle section 
struts, above and below the beams. It is preferable, however, to 
attach the rear outriggers to extra bolts running through the beams, 
so that when the machine is to be housed the tail and rudder can be 
unshipped and the triangular frames swung around against the main 
frame, considerably reducing the space required. 

The tail, horizontal and vertical rudders, and the ailerons are 
light frames of wood, covered on both sides with the same kind of 
cloth as the main planes or wings. These frames are braced with 
piano wire in such a manner that no twisting strains can be put on 
them. The front horizontal rudder, which is of biplane 
construction like the main cell, is built up with struts in the same way. Instead 
of being fitted with sockets, however, the struts are held by long 
screws run through the planes and into their ends, passing through 
the eyes of the turnbuckles. 

DETAILS OF CONSTRUCTION
#######################

**Main Planes and Struts**. It is preferable to begin with the 
construction of the main planes and their struts and truss wires, 
the ribs already described being the first step. 

The main beams offer no special difficulties. They are ovals 
1 1/4 by 1 5/8 inches, all 6 feet long except the eight end ones, which 
are 6 feet 2 inches. The beams of the central section should be of 
ash, or should be thicker than the others. In the latter case, they 
must be tapered at the ends so that the clamping sleeves will fit and 
the additional wood must be all on the lower side, so that the rib will 
not be thrown out of alignment. The spruce used for the other beams 
should be reasonably clear and straight grained, but a small knot 
or two does not matter, provided it does not come near the ends of 
the beam. The beams may be cut to the oval shape by the sawmill 
or planed down by hand. 

"Fish-shaped" or "stream-line" section, as it is more commonly 
termed, is used for the struts, Fig. 15. It is questionable whether 
this makes any material difference in the wind resistance, but it is 
common practice to follow it in order to minimize this factor. It is 
more important that the struts be larger at their centers than at the 
ends, as this strengthens them considerably. At their ends the 
struts have ferrules of the 1-inch brass or steel tubing, and fit into 
the sockets which clamp the ribs and beams together. The material 
is spruce but the four central struts which carry the engine bed should 
either be ash or of larger size, say 1 1/4 by 3 inches. 

*Care Necessary to Get Planes Parallel*. The front struts must 
be longer than the rear ones by the thickness of a main rib at the 
point where the rear strut bolt passes through it, less the thickness 
of the rib ferrule through which the bolt of the front strut must 
pass. However, the first distance is not really the actual thickness 
of the rib, but the distance between the top of the rear beam and the 
bottom of the strut socket. In the drawings the difference in length 
between the front and rear struts is given as 2 inches, but it is 
preferable for the builder to leave the rear struts rather long and then 
measure the actual distance when assembling, cutting the struts to 
fit. The ends of the struts should also be countersunk enough to 
clear the head of the socket bolt. 

One of the items which the builder can not well escape buying 
in finished form is the strut sockets. These are cup-shaped affairs 
of pressed steel which sell at 20 cents each. Sixteen of them will be 
required for the main frame, and a dozen more can advantageously 
be used in the front and rear controls, though for this purpose they 
are not absolutely necessary. They can also be obtained in a larger 
oval size suitable for the four central struts that carry the engine 
bed, as well as in the standard 1-inch size. The bolts which project 
through the bottom of the sockets are ordinary 1/4-inch stove bolts, 
with their heads brazed to the sockets. 

For the rear struts, where the bolt must pass through the 
slanting main rib, it is advisable to make angle washers to put under the
socket and also between the beam and rib. These washers are made 
by sawing up a piece of heavy brass tubing, or a bar with a 1/4-inch 
hole drilled in its center, the saw cuts being taken alternately at 
right angles and at 60 degrees to the axis of the tube. 

The sleeves which clamp together the ends of the beams are 
made of sheet steel of about 20 gauge. The steel is cut out on the 
pattern given in the drawing, Fig. 16, and the 3/16-inch bolt holes 
drilled in the flanges. The flanges are bent over by clamping the 
sheet in a vise along the bending line and then beating down with a 
hammer. Then the sleeves can be bent into shape around a stray 
end of the beam wood. The holes for the strut socket bolts should 
not be drilled until ready to assemble. Ordinarily, 3/16-inch stove 
bolts will do to clamp the flanges together. 

Having reached this stage, the amateur builder must now supply 
himself with turnbuckles. As already mentioned, these may either 
be purchased or made by hand. It is permissible to use either one 
or two turnbuckles on each wire. One is really sufficient, but 
two—one at each end—add but little weight and give greater leeway in 
making adjustments. As there are about 115 wires in the machine 
which need turnbuckles, the number required will be either 115 
or 230, depending upon the plan which is followed. Those of the 
turnbuckles to be used on the front and rear controls and the ailerons, 
about one-fifth of the total number, may be of lighter stock than those 
employed on wires which carry part of the weight of the machine. 

**Making Turnbuckles for the Truss Wires**. On the supposition 
that the builder will make his own turnbuckles, a simple form is 
described here. As will be seen from Fig. 16, the turnbuckles are 
simply bicycle spokes, with the nipple caught in a loop of sheet steel 
and the end of the spoke itself twisted into an eye to which the truss 
wire can be attached. The sheet steel used should be 18 or 16 gauge, 
and may be cut to pattern with a heavy pair of tin snips. The spokes 
should be 3/32 inch over the threaded portion. The eye should be 
twisted up tight and brazed so that it can not come apart. The 
hole in the middle of each strip is, of course, drilled the same size 
as the spoke nipple. The holes in the ends are 3/16 inch. 

In the original Curtiss machines, the turnbuckles were strung 
on the socket bolts one after another, sometimes making a pack of 
them half an inch thick. A much neater construction is shown in 
the drawings, in which the bolt pierces a single plate with lugs to 
which to make the turnbuckles fast by riveting. The plates are of 
different shapes, with two, three, or four lugs, according to the 
places where they are to be used. They are cut from steel stock 
3/32 inch thick, with 1/4-inch holes for the socket bolts and 3/16 inch, or 
other convenient size, for the rivets that fasten on the turnbuckles. 

The relative merits of cable and piano wire for trussing have 
not been thoroughly threshed out. Each has its advantages and 
disadvantages. Most of the well-known builders use cable; yet if 
the difference between 1,000 feet of cable at 2 1/4 cents per foot (the 
price for 500-foot spools), and 8 pounds of piano wire at 70 cents a 
pound, looks considerable to the amateur builder, let him by all 
means use the wire. The cable, if used, should be the 3/32-inch size, 
which will stand a load of 800 pounds; piano wire should be 24 gauge, 
tested to 745 pounds. It should be noted that there is a special 
series of gauges for piano wire, known as the music wire gauge, in 
which the size of the wire increases with the gauge numbers, instead 
of the contrary, as is usual with machinery wire gauges. 

One by no means unimportant advantage of the piano wire 
is that it is much easier to fasten into the turnbuckles. A small sleeve 
or ferrule, a 1/4-inch length of 1/8-inch tubing, is first strung on the 
wire. The end of the wire is then passed through the turnbuckle 
eye, bent up, thrust through the sleeve, and again bent down. When 
the machine is taken apart, the wire is not disconnected from the 
eye, but instead the turnbuckle spoke is unscrewed from the nipple. 
The shape of the sheet-steel loop should be such as to hold the latter 
in place. Cable, on the other hand, must be cut with about 2 inches 
to spare. After being threaded through the turnbuckle eye, the 
end is wound back tightly on itself and then soldered, to make certain 
that it can not loosen. 

With a supply of turnbuckles and cable or piano wire at hand, 
the builder may go ahead with the main box-like structure or cell, 
which should be completed except for the cloth covering, and in 
proper alignment, before taking up the construction of the running 
gear and controls. 

**Running Gear**. The running gear of the machine is built of 
seamless steel tubing, those parts which carry the weight of the 
machine direct being of 3/4-inch outside diameter, 16-gauge tubing,
while the others are 5/8-inch outside diameter, either 18 or 20 gauge. 
About 25 feet of the heavy and 45 feet of the light tubing will be 
required, in lengths as follows: Heavy, four 3-foot, three 4-foot; light, 
one 6-foot, two 4-foot 6-inch, and seven 4-foot pieces. Referring 
to Fig. 17, two diagonal braces from the rear beam to the engine 
bed, the V-shaped piece under the front engine bed struts and all 
of the rear frame except the horizontal piece from wheel to wheel, 
are of heavy tubing. The horizontal in the rear frame, diagonals 
from the rear wheels and the rear end of the skid to the front beam, 
the two horizontals between the front and rear beam, and the 
forward V are of light tubing. 

.. figure:: images/Image20.jpg
   :align: center
   :scale: 85 %
   :alt: Fig. 17. Details of Curtiss Running Gear
   
   Fig. 17. Details of Curtiss Running Gear 

Three ash beams are used in the running gear. Two of these 
run diagonally from the rear end of the engine bed to the front wheel. 
These are about 10 feet long and 1 by 1 3/4 inches section. The third, 
which on rough ground acts as a skid, is 8 1/2 feet long and about 2 
inches square. Between the joints where the tubing frames are 
attached to it, the upper corners may be beveled off with a spoke 
shave an inch or more down each side. The beams are attached to 
the front wheel with strips of steel stock 1 1/2 inches wide and 1/8 inch 
thick. The engine bed beams are also ash about 1 by 1 3/4 inches 
section. Their rear ends are bolted to the middle of the rear engine 
bed struts and the front ends may be 1/2 inch higher. 

.. figure:: images/Image21.jpg
   :figclass: white-space-pre-line
   :align: center
   :scale: 85 %
   :alt: SCENE AT AVIATION MEET AT ROUEN, FRANCE, SHOWING AN ANTOINETTE MONOPLANE MAKING A TURN
   
   SCENE AT AVIATION MEET AT ROUEN, FRANCE, SHOWING AN ANTOINETTE MONOPLANE MAKING A TURN 
   *This Photograph Protected By International Copyright* 

.. figure:: images/Image22.jpg
   :figclass: white-space-pre-line
   :align: center
   :scale: 85 %
   :alt: A FRENCH MONOPLANE TRAVELLING SIXTY-FIVE MILES AN HOUR
   
   A FRENCH MONOPLANE TRAVELLING SIXTY-FIVE MILES AN HOUR
   *This Photograph Protected By International Copyright* 

The wheels are usually 20 by 2 inches, and of the bicycle type, 
but heavier and wider in the hub; the tires are single tube. These 
wheels, complete with tires, cost about $10 each. This size is used 
on the standard Curtiss machines, but novice operators, whose 
landings are not quite as gentle as they might be, find them easily broken. 
Therefore, it may be more economical in the end to pay a little more 
and get heavier tires—at least to start with. 

For working the tubing into shape, a plumber's blow torch is 
almost indispensable—most automobilists will already possess one 
of these. The oval, flat variety, holding about one pint, is very handy 
and packs away easily, but on steady work requires filling somewhat 
too frequently. With a dozen bricks a shield can be built in front of 
the torch to protect the flame and concentrate the heat. Whenever 
it is to be flattened and bent, the tubing should be brought to a 
bright red or yellow heat. Screwing the vise down on it will then 
flatten it quickly without hammer marks. Where the bend is to be 
made in the middle of the piece, however, it may be necessary to 
resort to the hammer and anvil. 

It is convenient to start with the framework under the rear 
beam. This may be drawn accurately to full size on the workshop 
floor, and the tubes bent to fit the drawing. With this framework once 
in place, a definite starting point for the remainder of the running gear 
is established. Here and in all other places, when boring through 
wood, the holes should be drilled out full, and larger washers should 
be placed under the bolt head and nut. All nuts should be provided 
with some sort of locking device The perspective drawing. Fig. 17, 
should show the general arrangement clearly enough to enable the 
builder to finish the running gear. 

**Outriggers**. Both the front and rear control members, or 
"outriggers" as they are termed, Fig. 12, may be conveniently 
built up on the central section of the main frame, which, it is assumed, 
has now been fitted with the running gear. 

The horizontal rudder, or "elevator," is a biplane structure like 
the main cell of the machine, but with fewer struts; it is carried in 
front of the main planes on two **A**-shaped frames. The vertical 
rudder, at the rear, is split along the middle and straddles a fixed 
horizontal plane, or *tail*. This also is carried on two **A**-shaped 
frames. Lateral stability is controlled by two auxiliary planes or 
ailerons, one at each side of the machine and carried on the two outer
front struts. These three control units—*elevator*, *tail* and *rudder*, and 
*ailerons*—will now be taken up separately and their construction, 
location on the machine, and operation will be described. 

.. figure:: images/Image23.jpg
   :align: center
   :scale: 85 %
   :alt: Fig. 18. Details of Rudders and Ailerons, Curtiss Biplane 
   
   Fig. 18. Details of Rudders and Ailerons, Curtiss Biplane 

*Horizonal Rudder or Elevator*. The two planes of the elevator 
are 2 feet wide by 5 feet 8 inches long and are spaced 2 feet apart, 
being held in this position by ten struts. The frames of the planes 
are built of spruce sticks 1/2 by 1 inch, each plane having two sticks 
the full length and five evenly spaced crosspieces or ribs. These 
are joined together with squares of X-sheet tin, as shown in the 
detailed drawing, Fig. 18. With a little experimenting, paper 
patterns can be made from which the tin pieces can be cut out. 
The sticks are then nailed through the tin with 3/4-inch brads. 

It is convenient to draw the frames out accurately on a smooth 
wood floor and then work over this drawing. The first few brads 
will hold the sticks in place. When all the brads have been driven, 
a little drop of solder should be run in around the head of each one. 
This is a tedious job. One must be careful to use no more solder than 
necessary as it increases the weight very rapidly. Two pounds of 
wire solder should be sufficient for all the control members which are 
built in this way. When the top side is soldered, pry the frame loose 
from the floor with a screwdriver and turn it over. Then the 
projecting points of the brads must be clinched and the soldering repeated. 

At this stage, the two frames should be covered on both sides 
with the prepared cloth used for covering the main planes. The 
method of preparing this cloth is detailed a little farther along. 

The struts, so-called, to continue the analogy with the main 
planes, are turned sticks of spruce 3/8 inch in diameter. They are 
fitted at each end with ferrules of thin 3/8-inch brass, or steel tubing, 
driven on tight. Instead of using sockets, the struts are held at each 
end, simply by a long wood screw driven through the tin and wood 
of the plane frame and into the strut. These screws also hold the 
turnbuckles for the truss wires. For trussing purposes, the elevator 
is regarded as consisting of two sections only, the intermediate struts 
being disregarded. 

The turnbuckles and wire used here and in the other control 
members may well be of lighter stock than those used in the main 
planes. Piano wire, No. 18, or 1/16-inch cable is amply strong. The 
sheet steel may be about 22 gauge, instead of 16, and the bicycle 
spokes smaller in proportion. No turnbuckle plates are necessary. 
The screws running into the struts may be passed directly through 
the eyes of the turnbuckles, where they would have been attached 
to the turnbuckle plate. In order to secure a square and neat 
structure, those struts which have turnbuckles at their ends should be 
made a trifle shorter than the others. 

At each end, the elevator has an **X**-shaped frame of 1/4-inch steel 
tubing; at the intersection of the **X**'s are pivots on which the elevator 
is supported. Each **X** is made of two tubes, bent into a y and 
flattened and brazed together at the points. The ends of the **X**'s are 
flattened and bent over so that the screws which hold the struts 
in place may pass through them. 

.. figure:: images/Image24.jpg
   :align: center
   :scale: 85 %
   :alt: Fig. 19. Curtiss Biplane Ready for Flight
   
   Fig. 19. Curtiss Biplane Ready for Flight 

To the front middle 
strut is attached an 
extension which acts as a lever 
for operating the elevator. 
This is a stick of spruce 3/4 
inch in diameter and 3 feet 
3 inches long. At its upper 
end it has a ferrule of steel 
tubing, flattened at the 
end. The lower part of 
the stick may be fastened 
to the strut by wrapping 
the tube with friction tape, 
or by improvising a couple 
of sheet steel clamps. The 
upper end of the stick is 
braced by a 1/4-inch steel 
tube, extending to the top 
of the rear middle strut, 
and held by the same 
screw as the strut. This 
extension lever is 
connected to the steering column 
by a bamboo rod, 1 inch 
in diameter and about 10 
feet long, provided with 
flattened ferrules of steel 
tubing at each end. Each 
ferrule should be held on 
by a 1/8-inch stove bolt 
passing through it. 

*Front and Rear Outrigger 
Frames*. Both the front 
elevator and the tail and 
rudder at the rear, are 
carried, as mentioned above, 
each on a pair of **A**-shaped 
frames, similar to one 
another, except that those in the rear are longer than those in the 
front. Both are made of spruce of about the same section as used 
for the struts of the main frame. These pieces may either be full 
length, or they may be jointed at the intersection of the crosspieces, 
the ends being clamped in a sheet-steel sleeve, just like that used 
on the beams of the main frame. In this case, it is advisable to 
run a 1/8-inch stove bolt through each of the ends. 

.. figure:: images/Image25.jpg
   :align: center
   :scale: 85 %
   :alt: Fig. 20. Details of Outriggers and Front Elevating Planes as Seen from Driver's Seat
   
   Fig. 20. Details of Outriggers and Front Elevating Planes as Seen from Driver's Seat

The crosspieces of the **A**-frames are spruce of the same section, 
or a little smaller. At their ends may be used strut sockets like those 
of the main frame; or, if it is desired to save this expense, they may 
be fastened by strips of 1/16-inch steel stock with through bolts. 

The front outrigger has, besides the two A-frames, a rather 
complicated arrangement of struts designed to brace the front wheel 
against the shocks of landing. This arrangement does not appear 
very plain in a plan or elevation, and may best be understood by 
reference to the photograph, Fig. 19, and the perspective drawing, 
Fig. 20. Fig. 20 is a view from the driver's seat. The elevator is 
seen in front, the **A**-frames at each side, and at the bottom the two 
diagonal beams to the engine bed and the skid. 

Reference to this drawing will show the two diagonals run from 
the front wheel up and back to the top of the main frame, and two 
more from the wheel forward to the short crosspieces near the apexes 
of the **A**-frame: there is also a vertical strut which intersects two 
horizontal pieces running between the ends of the longer crosspieces 
of the **A**-frames. Altogether, there are five attachments on each side 
of the front wheel, through which the axle bolt must pass, viz, the 
connections to the skid, to one of the diagonals to the engine bed, 
to one of the rear diagonals, to one of the front diagonals, and to one 
side of the fork carrying the vertical strut. Of these the skid 
attachments should be on the inside closest to the wheel, and the engine 
bed diagonals next. 

The four additional diagonals running to the front wheel may 
be spruce of the same section used in the **A**-frames, or turned one 
inch round. At each end they have flattened ferrules of steel tubing. 
The beams of the **A**-frames have similar ferrules at the ends where 
they attach to the main frames. These attachments should be made 
on the socket bolts of the struts on either side of the middle 6-foot 
section and on the outer side of the main beams—not between the 
beam and the socket itself. 

It is possible, of course, to make all the **A**-frames and diagonal 
braces of bamboo, if desired, the qualities of this material already 
having been referred to. Bamboo rods for this purpose should be 
between 1 and 1 1/4 inches in diameter. Where ferrules are fitted on 
the ends, the hole of the bamboo should be plugged with wood glued 
in place. 

Generally, in the construction of the outrigger frames, the 
builder can use his own discretion to a considerable extent. There 
tire innumerable details which can be varied—far too many to 
consider even a part of the possibilities in this connection. If the builder 
runs across any detail which he does not see mentioned here, he may 
safely assume that any workmanlike job will suffice. Often, the 
method may be adapted to the materials on hand. The diagonal 
wires from the crosspieces of the A-frames to the struts should be 
crossed. 

*Rudder and Tail Construction*. The frame for the rudder and 
tail are constructed in much the same way as those for the elevator, 
Fig. 18. Spruce sticks 1 by 1/2 inch are used throughout, except for 
the piece at the back edge of the rudder and the long middle piece 
across the tail; these should be 1 1/2 by 1/2 inch. This long middle piece 
of the tail is laid across on top of the rest of the framework. When 
the cloth is put on, this makes the upper surface slightly convex while 
the lower surface remains flat. The ends of this piece should be 
reinforced with sheet steel, fairly heavy and drilled for 1/4-inch bolts, 
attaching the tail to the **A**-frames. 

The rudder is hung from two posts extending above and below 
the tail. These posts may be set in cast aluminum sockets, such as 
may be obtained from any supply house for 20 cents apiece. The 
posts need not be more than 3/4 inch in diameter. At their outer ends, 
they should have ferrules of steel tubing, and the turnbuckles or other 
attachments for the truss wires should be attached by a wood screw 
running into the end of each. From these posts the rudder may be 
hung on any light hinges the builder may find convenient, or on 
hinges improvised from screw eyes or eye bolts, with a bolt passing 
through the eyes of each. 

In steering, the rudder is controlled by a steering wheel carried 
on a hinged post in front of the pilot. This post should be ash about 
1 by 1 1/4 inches. It hinges at the bottom on a steel tube of 1/2-inch 
diameter which passes through it and is supported at the ends on 
diagonal beams to the engine bed. Two diagonals of lighter tubing 
may be put in to hold the posts centered between the two beams. 

The post is, of course, upright, and the hub of the wheel is 
horizontal. The wheel may be conveniently mounted on a piece of 
tubing of the same size as the hub hole, run through the post and 
held by a comparatively small bolt, which passes through it and has 
a big washer on either end. The wheel is preferably of the 
motor-boat variety with a groove around the rim for the steering cable. 

The rear edge of the tail should be about 1 inch lower than the 
front. To make the rudder post stand approximately vertical, 
wedge-shaped pieces of wood may be set under the sockets. 

The steering connections should be of flexible cables of steel 
such as are made for this purpose. There should be a double pulley 
on the post just under the wheel, and the cables should be led off 
the post just at the hinge at the bottom, so that swinging the post 
will not affect them. The cable is then carried under the lower main 
plane and out the lower beams of the **A**-frames. It is attached to 
the rudder at the back edge; snap hooks should be used for easy 
disconnection in packing. Perhaps the best way of guiding the cable, 
instead of using pulleys, is to run it through short pieces of tubing 
lashed to the beams with friction tape. The tubing can be bent 
without flattening by first filling it with melted lead, which, after 
the bending, can be melted out again. 

**Ailerons for Lateral Stability**. The framework of the ailerons 
is made in the same way as that for the elevator, tail, and rudder, 
Fig. 18. The pieces around the edges should be 1 1/2 by 1/2 inch, as 
also the long strip laid over the top of the ribs. The ribs should be 
1/2 by 3/4 inch. Each aileron has two holes, one for the strut to pass 
through, and the other for the diagonal truss wires at their 
intersection. The back edge also has a notch in it to clear the fore and 
aft wires. Each aileron is hung on four strips of soft steel about 1/2 
by 3/16 inch, twisted so that one end is at right angles to the other. 
These are arranged one on each side of the strut which passes through 
the aileron, and one at each end. Bolts through the struts carry three 
of them and the outer one is trussed by wires to each end of the outer 
strut. 

A frame of 1/4-inch steel tubing fits around the aviator's shoulders 
and is hinged to the seat, so that he can move it by leaning from one 
side to the other. This is connected by flexible cable to the rear 
edges of the ailerons, so that when the aviator leans to the left, he 
will raise the left and lower the right aileron. The upper edges of 
the ailerons are directly connected to each other by a cable running 
along the upper front beam, so that they must always move together. 

**Covering of the Planes**. Mention has already been made of 
the fact, in the general description of the machine, that light sail 
cloth, as employed on the Wright machines, may be used for the 
planes or wings. As a matter of fact, many different materials may 
be successfully employed, the selection depending upon the builder 
himself and his financial resources. About 55 square yards of material 
will be required, and in comparing prices always compare the width 
as this may vary from 28 to 55 inches. Rubberized silk which is used 
on the standard Curtiss machines is the most expensive covering, 
its cost running up to something like two hundred dollars. There 
are also several good aero fabrics on the market which sell at 60 
cents a square yard, as well as a number of brands of varnish for the 
cloth—most of them, however, quite expensive. The most economical 
method is to employ a strong linen cloth coated with shellac, which 
will be found very satisfactory. 

The covering of the frames with the cloth may well be 
postponed until after the engine has been installed and tested, thus 
avoiding the splashing of oil and dirt which the fabric is apt to receive 
during this operation. The wire to which the cloth is laced, must 
be strung along the rear ends of the ribs of each plane. The wires 
pass through holes in the ends of the small ribs and are attached 
to the main ribs with turnbuckles. At the ends of the planes the 
main ribs must be braced against the pull of the wire by a piece of 
1/4-inch tubing running from the end of the rib diagonally up to the 
rear beam. Both turnbuckles and tube are fastened with one wood 
screw running into the end of the rib. 

The cloth should be cut to fit the panels between the main 
ribs and hemmed up, allowing at least an inch in each direction for 
stretch. Small eyelets should be put along the sides and rear edges 
an inch apart for the lacing. At the front edge, the cloth is tacked 
directly to the beam, the edge being taken well under and around 
to the back. Strong fish line is good material for the lacing. 

After the cloth is laced on, it must be tacked down to the small 
ribs. For this purpose, use upholstery tacks as they have big 
cup-shaped heads which grip the cloth and do not tear out. As an extra 
precaution a strip of heavy tape must be run over each rib under 
the tack heads. All the control members are covered on both sides, 
the edges being folded under and held by tacks. 

**Making the Propeller**. If the completed biplane is to fly 
properly and also have sufficient speed to make it safe, 
considerable care must be devoted to the design and making of the 
propeller. Every aeroplane has a safe speed, usually referred to in 
technical parlance as its *critical speed*. In the case of the Curtiss 
biplane under consideration, this speed is about 40 miles an hour. 
By speeding up the motor considerably, it may be able to make 
42 to 43 miles an hour in a calm, such a condition representing the 
only true measure of an aeroplane's ability in this direction, while 
on the other hand, it would not be safe to let its speed with relation 
to the wind (not to the ground) fall much below 35 miles an hour. 
At any slower rate of travel, its dynamic stability would be 
precarious and the machine would be likely to dive to the ground 
unexpectedly. The reasons for this have been explained more in detail 
under the heading of "The Internal Work of the Wind." 

The necessity of making the propeller need not discourage the 
ambitious builder—if he can spare the time to do it right, it will 
be excellent experience. If not, propellers designed for driving a 
machine of this size can be purchased ready to mount from any one 
of quite a number of manufacturers. But as the outlay required 
will be at least $50, doubtless most experimenters will prefer to 
undertake this part of the work as well as that of building the 
framework and main cell, particularly as more than 90 per cent of the 
sum mentioned is represented by labor. The cost of the material 
required is insignificant by comparison. 

*True-Screw Design*. First it will be necessary to design the 
propeller to meet the requirements of the biplane itself. As this is 
a matter that has already been gone into in considerable detail 
under the appropriate heading, no further explanation of propeller 
characteristics or of the technical terms employed, should be needed 
here. We will assume that the biplane is to have a speed of 40 miles 
per hour in still air with the motor running at 1,200 r.p.m. With 
this data, it will not be difficult to calculate the correct pitch of the 
propeller to give that result. Thus 

40 X 5,280 X 100 / 60 X 1,200 X 85 = 3.45

or in round numbers a pitch of 3 1/2 feet. 40 (the speed in miles per 
hour) times 5,280 (feet per mile) divided by 00 (minutes in an hour) 
gives the speed of the aeroplane in feet per minute. Dividing this by 
1,200 (revolutions per minute) gives the number of feet the aeroplane 
is to advance per revolution of the propeller. The "100/85" part of 
the equation represents the efficiency of the propeller which can 
safely be figured on, *i.e.*, 85 per cent, or an allowance for slip of 15 
per cent. Forty miles an hour is the maximum speed to be expected, 
while the r.p.m. rate of the engine should be that at which it operates 
to the best advantage. 

The merits of the *true-screw* and *variable-pitch* propellers have 
already been dwelt upon. The former is not only more simple to 
build, but experience has shown that, as generally employed, it 
gives better efficiency. Hence, the propeller under consideration 
will, be of the true-screw type. Its pitch has already been calculated 
as 3 1/2 feet. For a machine of this size and power, it should be 6 feet 
in diameter. Having worked out the pitch and decided upon the 
diameter, the next and most important thing is to calculate the pitch 
angle. It will be evident that no two points on the blade will travel 
through the air at the same speed. Obviously, a point near the tip 
of the propeller moves faster than one near the hub, just as in 
rounding a curve, the outer wheel of an automobile has to travel faster 
than the inner, because it has to travel farther to cover the same 
ground. For instance, taking the dimensions of the propeller in 
question it will be seen that its tips will be traveling through the air 
at close to 4.3 miles per minute, that is, 

6 X π X 1200 / 5,280 = 4.28 

in which 6, the diameter of the propeller in feet, times π gives the 
circumference of the circle which is traveled by the blade tips 1,200 
times per minute; this divided by the number of feet per mile gives 
the miles per minute covered. On the other hand, a point on the 
blade but 6 inches from the hub will turn at only approximately 
3,500 feet per minute. Therefore, if every part of the blade is to 
advance through the air equally, the inner part must be set at a 
greater angle than the outer part. Each part of the blade must be 
set at such an angle that at each revolution it will move forward 
through the air a distance equal to the pitch. This is known as the 
pitch angle. The pitch divided by the circumference of the circle 
described by any part of the blade, will give a quantity known as 
the tangent of an angle for that particular part. The angle 
corresponding to that tangent may most easily be found by referring to 
a book of trigonometric tables. 

.. figure:: images/Image26.jpg
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   :alt: Table II. Propeller Blade Data
   
For example, take that part of the blade of a 3 1/2-foot pitch 
propeller which is 6 inches from the center of the hub. Then 

3.5 X 12 / 6 X 2 π = 1.1141 tangent of 48 degrees 5 minutes 

in which 3.5 X 12 reduces the pitch to inches, while 6 X 2π  is the 
circumference of the circle described by the point 6 inches from the 
hub. However, in order to give the propeller blade a proper hold 
on the air, it must be set at a greater angle than these figures would 
indicate. That is, it must be given an angle of incidence similar to 
that given to every one of the supporting planes of the machine. 
This additional angle ranges from 2 degrees 30 minutes, to 4 degrees, 
depending upon the speed at which the particular part of the blade 
travels; the greater the speed, the less the angle. This does not apply 
to that part of the blade near the hub as the latter is depended upon 
solely for strength and is not expected to add to the effective thrust 
of the propeller. 

Table II shows the complete set of figures for a blade of 3 1/2-foot 
pitch, the angles being worked out for sections of the blade 3 inches 
apart. 

These angles are employed in Fig. 21, which shows one blade 
of the propeller and its cross sections. 

It should be understood that these calculations apply only to 
the type of propeller known as the *true screw*, as distinguished from 
the *variable pitch*. The design of the latter is a matter of personal 
skill and experience in its making which is hardly capable of 
expression in any mathematical formula. There are said to be only 
about three men in this country who know how to make a proper 
variable-pitch propeller, and it naturally is without advantage when 
made otherwise. 

.. figure:: images/Image27.jpg
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   :alt: Fig. 21. Details of Propeller Construction, Curtiss Biplane
   
   Fig. 21. Details of Propeller Construction, Curtiss Biplane

*Shaping the Blades*. Like the ribs, the propeller is made up 
of a number of laminations of boards finished true and securely 
glued, afterward being cut to the proper shape, though this process, 
of course, involves far more skill than in the former case. Spruce is 
the strongest wood for its weight, but it is soft and cracks easily. 
Maple, on the other hand, is tough and hard, so that it will be an 
advantage to alternate the layers of these woods with an extra 
maple board, in order to make both outside strips of the harder 
wood, so as to form a good backing for the steel flanges at the hub, 
the rear layer extending the full length of the thin rear edges of the 
blades. Other woods may be employed and frequently are used by 
propeller manufacturers, such as mahogany (not the grained wood 
used for furniture, but a cheaper grade which is much stronger), 
walnut, alternate spruce and whitewood, and others. 

The boards should be selected with the greatest care so as to 
insure their being perfectly clear, *i.e.*, absolutely free of knots, 
cross-grained streaks, or similar flaws, which would impair their 
strength and render them difficult to work smoothly. They should 
measure 6 inches wide by 6 feet 1 inch in length. Their surfaces 
must be finished perfectly true, so that they will come together 
uniformly all over the area on which they bear on one another, and 
the various pieces must be glued together with the most painstaking 
care. Have the glue hot, so that it will spread evenly, and see that 
it is of a uniform consistency, in order that it may be smoothly 
applied to every bit of the surface. They must then be clamped 
together under as much pressure as it is possible to apply to them 
with the means at hand, the rib press already described in detail 
forming an excellent tool for this purpose. Tighten up the nuts 
evenly a little at a time, avoiding the application of excessive or 
uneven pressure at one point, continuing the gradual tightening up 
process until it can not be carried any farther. This is to prevent the 
boards from assuming a curve in drying fast. Allow at least 
twenty-four hours for drying, during which period the laminated block should 
be kept in a cool, dry place at as even a temperature as possible. 

Before undertaking the remainder of the work, all of which 
must be carried out by hand, with the exception of cutting the 
block to the outline of the propeller, which may be done with a band 
saw, a set of templates or gauges should be made from the drawings. 
These will be necessary as guides for finishing the propeller accurately. 
Draw the sections out full size on sheets of cardboard or tin and 
cut out along the curves, finally dividing each sheet into two parts, 
one for the upper side and one for the lower. Care must be taken 
to get the sides of the template square, and when they are used, the 
propeller should be laid on a perfectly true and flat block. Each 
template should be marked as it is finished, to indicate what part 
of the blade it is a gauge for. The work of cutting the laminated 
block down to the lines represented by the templates is carried out 
with the aid of the plane, spoke shave, and gouge. After the first 
*roughing out* to approximate the curvature of the finished propeller 
is completed, the cuts taken should be very fine, as it will be an easy 
matter to go too deep, thus spoiling the block and necessitating a 
new start with fresh material. For finishing, pieces of broken glass 
are employed to scrape the wood to a smooth surface, followed by 
coarse and finally by fine sandpaper. 

*Mounting*. The hub should be of the same diameter as the 
flange on the engine crank shaft to which the flywheel was bolted, 
and should have its bolt holes drilled to correspond. To strengthen 
the hub, light steel plates of the same diameter are screwed to it, 
front and back, and the bolt holes drilled right through the metal 
and wood. This method of fastening is recommended where it is 
possible to substitute the propeller for the flywheel formerly on the 
engine, it being common practice to omit the use of the flywheel 
altogether. The writer does not recommend this, however, as the 
advantages of smoother running and more reliable operation gained 
by the use of a flywheel in addition to the propeller far more than 
offset any disadvantage represented by its weight. It will be noted 
that the Wright motors have always been equipped with a flywheel 
of ample size and weight and this is undoubtedly responsible, in some 
measure at least, for the fact that the Wright biplanes fly with 
considerably less power than is ordinarily employed for machines of 
the same size. If the motor selected be equipped with an unusually 
heavy flywheel, and particularly where the wheel is of comparatively 
small diameter, making it less effective as a balancer, it may be 
replaced with one of lighter weight and larger diameter. It may be 
possible to attach it by keying to the forward end of the crank shaft, 
thus leaving the flange from which the flywheel was taken free for 
mounting the propeller. An ordinary belt pulley will serve 
excellently as the new flywheel, as most of its weight is centered in its rim, 
but as the common cast-iron belt pulley of commerce is seldom 
intended to run at any such speed as that of an automobile motor, 
it should be examined carefully for flaws. Otherwise, there will be 
danger of its blunting with disastrous results under the influence of 
centrifugal force. Its diameter should not exceed 16 inches in order 
to keep its peripheral speed within reasonable limits. Where the 
mounting of the motor permits of its use, a wood pulley 18 to 20 
inches in diameter with a steel band about 1/8 to 1/4-inch thick, shrunk 
on its periphery, may be employed. Most builders will ridicule the 
idea of a flywheel other than the propeller itself. "You do not need 
it; so why carry the extra weight?" will be their query. It is not 
absolutely necessary, but it is an advantage. 

In case the flywheel of the engine selected is keyed to the crank 
shaft, or in case it is not possible to mount both the flywheel and 
the propeller on different ends of the crank shaft, some other expedient 
rather than that of bolting to the flange must be adopted. In such 
a case, the original flywheel, where practical to retain it, may be 
drilled and tapped and the propeller attached directly to it. Where 
the flywheel can not be kept, it will usually be found practical to 
cut off its rim and bolt the propeller either to the web or spokes, or 
to the flywheel hub, if it be cut down to the latter. 

The drawing. Fig. 21, shows the rear or concave side of the 
propeller. From the viewpoint of a man standing in its wind and 
facing forward, it turns to the left, or anti-clockwise. On many of 
the propellers now on the market, the curved edge is designed to go 
first. This type may have greater advantages over that described, 
but the straight front edge propeller is easier for the amateur to 
make. 

**Mounting the Engine**. Having completed the propeller, the 
next step is the mounting of the engine. Reference to the types 
available to the amateur aeroplane builder has already been made. 
There are a number of motors now on the market that have been 
designed specially for this purpose and not a few of them are of 
considerable merit. Their cost ranges from about $250 up to $2,500, 
but it may be possible to pick up a comparatively light-weight 
automobile motor second hand which will serve all purposes and 
which will cost far less than the cheapest aeronautic motor on the 
market. It must be capable of developing 30 actual horse-power 
at 1,000 to 1,200 r.p.m. and must not exceed 400 pounds complete 
with all accessories, such as the radiator and piping, magneto, water, 
oil, etc. Considerable weight may be saved on an automobile motor 
by removing the exhaust manifold and substituting a lighter flywheel 
for the one originally on the engine—or omitting it altogether, as 
just mentioned. A light-weight aeronautic radiator should be used 
in preference to the usual automobile radiator. 

When placing the engine in position on the ash beams forming 
its bed or support, it must be borne in mind that the complete 
machine, with the operator in the aviator's seat, is designed to 
balance on a point about 1 1/2 feet back of the front edge of the main 
planes. As the operator and the motor represent much the larger 
part of the total weight, the balance may easily be regulated by 
moving them slightly forward or backward, as may be required. 
It will be necessary, of course, to place the engine far enough back 
in any case to permit the propeller blades to clear the planes. The 
actual installation of the engine itself will be an easy matter for 
anyone who has had any experience in either automobile or marine 
gasoline motor work. It is designed to be bolted to the two engine 
beams in the same manner as on the side members of the frame of 
an automobile, or the engine bed in a boat. Just in front of the 
engine is the best place for the gasoline tank, which should be 
cylindrical with tapering ends, to cut down its wind resistance. If the 
designer is not anxious to carry out points as fine as this, a light 
copper cylindrical tank may be purchased from stock. It should 
hold at least ten gallons of gasoline. In front of the tank is the 
radiator. 

**Controls**. The controls may be located to conform to the 
builder's own ideas of accessibility and convenience. Usually the 
switch is placed on the steering column, and it may be of the ordinary 
*knife* variety, or one of the special switches made for this purpose, 
as taste may dictate. The throttle control and spark advance may 
either be in the form of pedals, working against springs, or of small 
levers working on a notched sector, at the side of the seat. The 
complete control, levers, and sector may be purchased ready to 
mount whenever desired, as they are made in this form for both 
automobile and marine work. This likewise applies to the wheel, 
which it would not pay the amateur to attempt to make. 

Another pedal should work a brake on the front wheel, the 
brake shoe consisting of a strip of sheet steel, fastened at one end 
to the fore part of the skid and pressed against the wheel by a bamboo 
rod directly connected with the brake pedal. An emergency brake 
can also be made by loosely bolting a stout bar of steel on the skid 
near its rear end; one end of this bar is connected to a lever near the 
seat, so that when this lever is pulled back the other end of the bar 
tends to dig into the ground. As making a landing is one of the most 
difficult feats for the amateur aviator to master and sufficient space 
for a long run after alighting is not always available, these brakes 
will be found a very important feature of the machine. 

.. figure:: images/Image28.jpg
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   :alt: Fig. 22. Method of Starting the Engine of an Aeroplane
   
   Fig. 22. Method of Starting the Engine of an Aeroplane

The engine is started by swinging the propeller, and this is an 
operation requiring far more caution than cranking an automobile 
motor. Both hands should be placed on the same blade. Fig. 22, 
and the latter should always be pulled downward—never upward. 
With the switch off, first turn the propeller over several times to 
fill the cylinders with gas, leaving it just ahead of dead center of one 
of the cylinders, and with one blade extending upward and to the 
left at a 45-degree angle. After closing the switch, take the left 
blade with both hands and swing it downward sharply, getting out 
of the way of the following blade as quickly as possible. 

**Tests**. The first thing to be done after the propeller is finished 
and mounted on the engine is to test the combination, or power 
plant of the biplane, for speed and thrust, or pulling power. From 
these two quantities it will be easy to figure the power that the 
engine is delivering. The only instruments necessary are a spring 
balance reading to 300 pounds or over; a revolution counter, such as 
may be procured at any machinist's supply house for a dollar or two; 
and a watch. One end of the spring balance is fastened to the front 
end of the skid and the other to a heavy stake firmly driven in the 
ground a few feet back. The wheels of the biplane should be set on 
smooth boards so that they will not offer any resistance to the 
forward thrust. When the engine is started the spring balance will 
give a direct reading of the pull of the propeller. 

With one observer noting the thrust, another should check the 
number of revolutions the engine is turning per minute. To do this, 
a small hole should previously have been countersunk in the hub 
of the propeller to receive the conical rubber tip of the revolution 
counter. The observer stands behind the propeller, watch in one 
hand and revolution counter in the other. At the beginning of the 
minute period, the counter is pressed firmly against the hub, and 
quickly withdrawn at the end of the minute. A stop watch is 
naturally an advantage for the purpose. The horse-power is figured as 
follows, assuming, for example, a thrust of 250 pounds at 1,200 r.p.m. 

250 X 1200 X 3.5 X 100 / 33.000 X 85 = 37 h. p. 

As before, the "100/85" allows for the slip and represents the 
efficiency of the propeller; 33,000 is the number of foot pounds per 
minute or the equivalent of one horse-power, and 3.5 is the pitch of 
the propeller. 

**Assembling the Biplane**. Assembling the machine complete 
requires more space than is available in the average workshop. 
However, it is possible to assemble the sections of the planes in a 
comparatively small room, carrying the work far enough to make 
sure that everything will go together properly when the time comes 
for complete assembly at the testing ground. In this case, it is 
preferable to assemble the end sections first, standing them away 
when complete to make room for the central section, on which the 
running gear and outriggers are to be built up. 

The builder will have decided by this time whether he will 
make his machine on the regular plan, with one main rib between 
each section, or on the quick-detachable plan, which has two main 
ribs on either side of the central section, as previously explained. 

It is desirable to be able to assemble two sections at once and 
this should be possible anywhere as it requires a space only about 
6 by 13 feet. Two wood 2X4's, about 12 feet long, should be nailed 
down on the blocks on the floor; make these level and parallel to 
each other at a distance of 3 feet 6 inches on centers, one being 3 
inches higher than the other. Strips of wood should be nailed on 
them, so as to hold the main beams of the frame in place while 
assembling. 

The two front and two rear beam sections are laid in place and 
joined with the sheet-steel sleeves, the flanges of the sleeves on the 
inner side of the beams. Then through the sleeves in the front 
beams, which are, of course, those on the higher bed, drill the holes 
for the strut socket bolts (1/4 inch). The holes for the outer ones go 
through the projecting ends of the beams; those for the inner ones 
are half in each of the two abutting beams. At the end where the 
central section joins on, a short length of wood of the same section 
may be inserted in the sleeve while drilling the hole. An assistant 
should hold the beams firmly together while the holes are being 
drilled. 

Now lay in place the three main ribs belonging to the two 
sections under construction and fasten them at the front ends by putting 
in place the strut sockets for which the holes have been drilled, with 
a turnbuckle plate under each socket, Fig. 16. The strut socket 
bolt passes through the main rib and the beam. The bed on which 
the assembling is being done, should be cut when sufficiently under 
the joints to leave room for the projecting bolt ends. Set the ribs 
square with the front beams, then arrange the rear beams so that 
their joints come exactly under the ribs; clamp the ribs down and 
drill a true, vertical hole through the rib beam, holding the two 
sections of the beam together as before. Then put the rear strut 
sockets in place, using the angle washers previously described, above 
and below the rib. 

When the quick-detachable plan is followed, the ribs at the 
inner ends of the double section, where they join the central section, 
should be bolted on an inch from the ends of the beam, using 1/4-inch 
stove bolts instead of the socket bolts. The sleeves should be slotted, 
so that they can slide off without removing these bolts, as the sleeves 
and ribs which occupy the position over the joints of the beams, 
belong to the central section. 

The sections should now be strung up with the diagonal truss 
wires which will make them rigid enough to stand handling. The 
wires are attached at each end to the flange bolts of the sleeves. 
Either one or two turnbuckles may be used on each wire, as already 
explained; if but one turnbuckle be used, the other end of the wire 
may be conveniently attached to a strip of sheet steel bent double 
and drilled for the bolt, like the sheet-steel slip of a turnbuckle. 
The attachment, of whatever nature, should be put between the 
end and the flange of the sleeve, not between the two flanges. 

Three or four ribs can be used on each section; four are 
preferable on sections of full 6-foot length. They are, of course, evenly 
spaced on centers. At the front ends, they are attached to the beam 
by wood screws through their flattened ferrules. The attachment to 
the rear beam is made with a slip of sheet steel measuring 1/2 by 3 
inches, bent over the rib and fastened to the beam at each side with 
a wood screw. A long wire nail is driven through the rib itself on 
the beam. 

Four double sections should be built up in this manner, the 
right and left upper and the right and left lower sections. Uppers 
and lowers are alike except for the inversion of the sockets in the 
upper sections. Rights and lefts differ in that the outer beams are 
long enough to fill up the sleeves, not leaving room for another beam 
to join on. 

Inserting the struts in their sockets between the upper and lower 
sections of the same side will now form either of the two sides of the 
machine complete. Care should be taken to get the rear struts the 
proper length with respect to the front ones to bring the upper and 
lower planes parallel. The distance from the top of the lower front 
beam to the top of the upper front beam should be the same as the 
distance between the rows of bracing holes in the upper and lower 
main ribs just above and below the rear struts—about 4 feet 6 inches. 
It should hardly be necessary to mention that the thick edges of the 
struts come to the front—they are fish-shaped and a fish is thicker 
at the head than at the tail. 

The truss wires may now be strung on in each square of the 
struts, beams, and main ribs, using turnbuckles as previously 
described. The wires should be taut enough to sing a low note when 
plucked between the thumb and forefinger. If the construction is 
carried out properly, the framework will stand square and true 
with an even tension on all the wires. It is permissible for the 
struts to slant backward a little as seen from the side, but all should 
be perfectly in line. 

For adjusting the turnbuckles, the builder should make for 
himself a handy little tool usually termed a nipple wrench. It is 
simply a strip of steel 1 1/2 by 1/2 by 3/32 inches, with a notch cut in the 
middle of the long sides to fit the flattened ends of the turnbuckle 
nipples. This is much handier than the pliers and does not burr up 
the nipples. 

It has been assumed in this description of the assembling that 
the builder is working in a limited space; if, on the contrary, he has 
room enough to set up the whole frame at once, the work will be 
much simpler. In this case, the construction bed should be 30 feet 
long. First build up the upper plane complete, standing it against 
the wall when finished; then build the lower plane, put the struts 
in their sockets, and lay on the upper plane complete. 

Returning to the plan of assembly by sections, after the side 
sections or wings of the machine have been completed, the struts 
may be taken out and the sections laid aside. The middle section, 
to which the running gear and outriggers will be attached, is now to 
be built up in the same way. If the builder is following the plan 
in which there is one main rib between each section, it will be 
necessary to take off the four inner main ribs from the sections already 
completed, to be used at the ends of the central section. The plan 
drawing of the complete machine shows that the ribs of the central 
section are cut off just back of the rear beam to make room for the 
propeller. This is necessary in order to set the motor far enough 
forward to balance the machine properly. The small ribs in this 
section have the same curve but are cut off 10 inches shorter at their 
rear ends, and the stumps are smoothed down for ferrules like those 
for the other small ribs. In the plan which has one main rib between 
each section, the main rib on each side of the central section must 
be left full length. In the quick-detachable plan with two main 
ribs on each side of the central section, the inner ones, which really 
belong to this section, are cut off short like the small ribs. 

In the drawing of the complete machine, the distance between 
the struts which carry the engine bed is shown as 2 feet. This is 
only approximate, as the distance must be varied to suit the motor 
employed. By this time, the builder will have decided what engine 
he is going to use—or can get—and should drill the holes for the 
sockets of these struts with due respect to the width of the engine's 
supporting feet or lugs, remembering that the engine bed beams go 
on the inside of the struts. In the drawing of the running gear. Fig. 
17, the distance between the engine-bed struts has been designated 
*A*. The distances, *B*, on each side are, of course, approximately 
(6'— 2*A*), whatever *A* may be. 

.. figure:: images/Image29.jpg
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   :alt: VIEW OF THE FRENCH AVIATION GROUNDS SHOWING THE HANGARS RANGED ALONG THE EDGES OF THE FIELD
   
   VIEW OF THE FRENCH AVIATION GROUNDS SHOWING THE HANGARS RANGED ALONG THE EDGES OF THE FIELD
   *This Photograph Protected By International Copyright*

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    EXAMINATION PAPER 

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    BUILDING AND FLYING AN 

    AEROPLANE 

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    **PART I**

**Read Carefully**: Place your name and full address at the head of the 
paper. Any cheap, light paper like the sample previously sent you may be 
used. Do not crowd your work, but arrange it neatly and legibly. *Do not 
copy the answers from the Instruction Paper; use your own words so that we 
may be sure that you understand the subject*. 

1. What type of machine, biplane or monoplane, makes the best glider and why? 

2. Give the dimensions of a glider which will support a man's weight. 

3. In a glider which has no rudder, how is the machine controlled? 

4. Give carefully the details of the start in making a glide. 

5. In what direction relative to the wind should a glide be made? Justify your answer. 

6. How must the stability and balance of a glider in flight be controlled? 

7. State the proper conditions for a successful glide. 

8. Give the essential characteristics of a Curtiss aeroplane, defining the various parts. 

9. Describe briefly the details of construction of the main supporting surfaces of a Curtiss. 

10. Draw a diagram of the assembled planes showing how the struts and cross wires are placed to give the required rigidity. 

11. Give the details of the running gear of the Curtiss. 

12. What is the office of the Curtiss ailerons and how are they controlled from the operator's seat? Draw sketch. 

13. Describe the details of the front and rear outriggers. 

14. What type of propeller is advised for the Curtiss? Give the details of its construction. 

15. Describe carefully the manner in which a propeller should move through the air in order to give the maximum propulsion. 

16. What determines the exact location of the motor in the aeroplane? 

17. Give correct method of starting the motor when ready for a flight. 

18. What tests should be conducted before a flight is undertaken? 

**After completing the work, add and sign the following statement:**

I hereby certify that the above work is entirely my own. 

(Signed) 

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PART II
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BUILDING A BLERIOT MONOPLANE
############################

As mentioned in connection with the description of its 
construction, the Curtiss biplane was selected as a standard of this type 
of aeroplane after which the student could safely pattern for a number 
of reasons. It is not only remarkably simple in construction, easily 
built by anyone with moderate facilities and at a slight outlay, but 
it is likewise the easiest machine to learn to drive. The monoplane is 
far more *difficult* and *expensive* to build. 

The Bleriot may be regarded as the most typical example in this 
field, in view of its great success and the very large numbers which 
have been turned out. In fact, the Bleriot monoplane is the product 
of a factory which would compare favorably with some of the large 
automobile plants. Its construction requires skillful workmanship 
both in wood and metal, and a great many special castings, forgings, 
and stampings are necessary. Although some concerns in this 
country advertise that they carry these fittings as stock parts, they 
are not always correct in design and, in any case, are expensive. 
Wherever it is possible to avoid the use of such parts by any expedient, 
both forms of construction are described, so that the builder may 
take his choice. 

Bleriot monoplanes are made in a number of different models, 
the principal ones being the 30-horse-power "runabout," Figs. 23 
and 24, the 50- and 70-horse-power passenger-carrying machines, 
and the 50-, 70-, and 100-horse-power racing machines. Of these the 
first has been chosen as best adapted to the purpose. Its construction 
is typical of the higher-power monoplanes of the same make, and it 
is more suitable for the beginner to fly as well as to build. It is 
employed exclusively by the Bleriot schools. 

.. figure:: images/Image30a.jpg
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   :alt: Fig. 23. Details of Bleriot Monoplane
   
.. figure:: images/Image30b.jpg
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   :alt: Fig. 23. Details of Bleriot Monoplane
   
   Fig. 23. Details of Bleriot Monoplane

**Motor**. The motor regularly employed is the 30-horse-power, 
three-cylinder Anzani, a two-cylinder type of which is shown in 
"Aeronautical Motors" Fig. 40. From the amateur's standpoint, a 
disadvantage of the Bleriot is the very short space allowed for the 
installation of the motor. For this reason, the power plant must be 
fan shaped, like the Anzani; star form, like the Gnome; or of the 
two-cylinder opposed type. It must likewise be air-cooled, as there 
is no space available for a radiator. 

.. figure:: images/Image31a.jpg
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   :alt: Fig. 24. Side Elevation of Bleriot Monoplane
   
   Fig. 24. Side Elevation of Bleriot Monoplane

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   :alt: Fig. 25. Top and Side View of Bleriot Fuselage on Which Machine Is Assembled
   
   Fig. 25. Top and Side View of Bleriot Fuselage on Which Machine Is Assembled

**Fuselage**. Like most monoplanes, the Bleriot has a long central 
body, usually termed "fuselage," to which the wings, running gear, 
and controls are all attached. A drawing of the fuselage with all 
dimensions is reproduced in Fig. 25, and as the machine is, to a large 
extent, built up around this essential, its construction is taken up 
first. It consists of four long beams united by 35 crosspieces. The 
beams are of ash, 1 3/16 inches square for the first third of their length 
and tapering to 7/8 inch square at the rear ends. Owing to the 
difficulty of securing good pieces of wood the full length, and also to 
facilitate packing for shipment, the beams are made in halves, the 
abutting ends being joined by sleeves of 1 1/8-inch, 20-gauge steel 
tubing, each held on by two 1/8-inch bolts. Although the length of 
the fuselage is 21 feet 11 1/4 inches, the beams must be made of two 
11-foot halves to allow for the curve at the rear ends. 

.. figure:: images/Image32.jpg
   :align: center
   :scale: 85 %
   :alt: Fig. 26. Details of U-bolt Which is a Feature of Bleriot Construction
   
   Fig. 26. Details of U-bolt Which is a Feature of Bleriot Construction

The struts are also of ash, the majority of them being 7/8 by 1 1/4
inches, and oval in section except for an inch and a half at each end. 
But the first, second, and third struts (counting from the forward 
end) on each side, the first and second on the top, and the first strut 
on the bottom are 1 3/16 inches square, of the same stock as the main 
beams. Practically all of the struts are joined to the main beams 
by U-bolts, as shown by the detail drawing, Fig. 26, this being one 
of Louis Bleriot's inventions. The small struts are held by 1/8-inch 
bolts and the larger ones by 3/16-inch bolts. The ends of the struts 
must be slotted for these bolts, this being done by drilling three holes 
in a row with a 5/32- or 7/32-inch drill, according to whether the slot is 
for the smaller or larger size bolt. The wood between the holes is 
cut out with a sharp knife and the slot finished with a coarse, flat file. 

All of the U-bolts measure 2 inches between the ends. The 
vertical struts are set 1 inch forward of the corresponding horizontal 
struts, so that the four holes through the beam at each joint are 
spaced 1 inch apart, alternately horizontal and vertical. To the 
projecting angles of the U-bolts are attached the diagonal truss wires, 
which cross all the rectangles of the fuselage, except that in which the 
driver sits. This trussing should be of 20-gauge piano wire 
(music-wire gauge) or 1/10-inch cable, except in the rectangles bounded by 
the large struts, where it should be 25-gauge piano wire or 3/32-inch 
cable. Each wire, of course, should have a turnbuckle. About 100 
of these will be required, either of the spoke type or the regular type, 
with two screw eyes—the latter preferred. 

Transverse squares, formed by the two horizontal and two 
vertical struts at each point, are also trussed with diagonal wires. 
Although turnbuckles are sometimes omitted on these wires, it takes 
considerable skill to get accurate adjustments without them. The 
extreme rear strut to which the rudder is attached, is not fastened in 
the usual way. It should be cut with tongues at top and bottom, 
fitting into notches in the ends of the beams, and the whole bound 
with straps of 20-gauge sheet steel, bolted through the beams with 
1/8-inch bolts. 

Continuing forward, the struts have no peculiarity until the 
upper horizontal one is reached, just behind the driver's seat. As it 
is impossible to truss the quadrangle forward of this strut, owing to 
the position of the driver's body, the strut is braced with a U-shaped 
half-round strip of 1/2 by 1 inch of ash or hickory bolted to the beams 
at the sides and to the strut at the rear, with two 1/8-inch bolts at each 
point. The front side of the strut should be left square where this 
brace is in contact with it. The brace should be steam bent with the 
curves on a 9-inch radius, and the half-round side on the inside of 
the curve. 

The vertical struts just forward of the driver's seat carry the 
inner ends of the rear wing beams. Each beam is attached with a 
single bolt, giving the necessary freedom to rock up and down in 
warping the wings. The upper 6 inches of each of these struts fits 
into a socket designed to reinforce it. In the genuine Bleriot, this 
socket is an aluminum casting. However, a socket which many would 
regard as even better can be made from a 7-inch length of 20-gauge 
1 1/8-inch square tubing. One end of the tube is sawed one inch through 
the corners; two opposite sides are then bent down at right angles to 
form flanges, and the other two sides sawed off. A 1- by 3-inch strip 
of 20-gauge sheet steel, brazed across the top and flanges completes 
the socket. With a little care, a very creditable socket can be made 
in this way. Finally, with the strut in place, a 3/8-inch hole is drilled 
through 4 inches from the top of the socket for the bolt securing the 
wing beam. 

The upper horizontal strut at this point should be arched about 
six inches to give plenty of elbow room over the steering wheel. 
The bending should be done in a steam press. The strut should be 
1 3/16 inches square, cut sufficiently long to allow for the curve, and 
fitted at the ends with sockets as described above, but set at an angle 
by sawing the square tube down further on one side than on the other. 

On the two lower beams, is laid a floor of half-inch boards, 
extending one foot forward and one foot back of the center line of the 
horizontal strut. This floor may be of spruce, if it is desired to save 
a little weight, or of ordinary tongue-and-grooved floor boards, 
fastened to the beams with wood screws or bolts. The horizontal 
strut under this floor may be omitted, but its presence adds but little 
weight and completes the trussing. Across the top of the fuselage 
above the first upper horizontal strut, lies a steel tube which forms 
the sockets for the inner end of the front wing beams. This tube is 
1 3/4 inches diameter, 18 gauge, and 26 3/4 inches long. It is held fast by 
two steel straps, 16 gauge and 1 inch wide, clamped down by the nuts 
of the vertical strut U-bolts. The center of the tube is, therefore, in 
line with the center of the vertical struts, not the horizontal ones. 
The U-bolts which make this attachment are, of course, the 3/16-inch 
size, and one inch longer on each end than usual. To make a neat 
job, the tube may be seated in wood blocks, suitably shaped, but 
these must not raise it more than a small fraction of an inch above 
the top of the fuselage, as this would increase the angle of incidence 
of the wings. 

The first vertical struts on each side are extras, without 
corresponding horizontal ones; they serve only to support the engine. 
When the Gnome motor is used, its central shaft is carried at the 
centers of two **X**-shaped, pressed-steel frames, one on the front side, 
flush with the end of the fuselage and one on the rear. 

**Truss Frame Built on Fuselage**. In connection with the fuselage 
may be considered the overhead truss frame and the warping frame. 
The former consists of two inverted **V**'s of 20-gauge, 1- by 3/8-inch oval 
tubing, joined at their apexes by a 20-gauge, 3/4-inch tube. Each **V** 
is formed of a single piece of the oval tubing about 5 feet long. The 
flattened ends of the horizontal tube are fastened by a bolt in the 
angles of the **V**'s. The center of the horizontal tube should be 2 feet 
above the top of the fuselage. The flattened lower ends of the rear **V** 
should be riveted and brazed to strips of 18-gauge steel, which will 
fit over the bolts attaching the vertical fuselage struts at this point. 
The legs of the front **V** should be slightly shorter, as they rest on top 
of the wing socket tube. Each should be held down by a single 
3/16-inch bolt, passing through the upper wall of the tube and its 
retaining strap; these bolts also serve the purpose of preventing the 
tube from sliding out from under the strap. Each side of the frame 
is now braced by diagonal wires (No. 20 piano wire, or 1/14-inch cable) 
with turnbuckles. 

At the upper corners of this frame are attached the wires which 
truss the upper sides of the wings. The front wires are simply 
fastened under the head and nut of the bolt which holds the frame 
together at this corner. The attachment of the rear wires, however, 
is more complex, as these wires must run over pulleys to allow for 
the rocking of the rear wing beams when the wings are warped. To 
provide a suitable place for the pulleys, the angle of the rear **V** is 
enclosed by two plates of 20-gauge sheet steel, one on the front and 
one on the rear, forming a triangular box 1 inch thick fore and aft, 
and about 2 inches on each side, only the bottom side being open. 
These plates are clamped together by a 3/16-inch steel bolt, on which 
are mounted the pulleys. There should be sufficient clearance for 
pulleys 1 inch in diameter. The wires running over these pulleys 
must then pass through holes drilled in the tube. The holes should 
not be drilled until the wings are on, when the proper angle for them 
can be seen. The cutting and bending of the steel plates is a matter 
of some difficulty, and should not be done until the frame is otherwise 
assembled, so that paper patterns can be cut for them. They should 
have flanges bent around the tube, secured by the bolts which hold 
the frame together, to keep them from slipping off. 

The oval tubing is used in the vertical parts of this frame, 
principally to reduce the wind resistance, being placed with the 
narrow side to the front. However, if this tubing be difficult to 
obtain, or if price is a consideration, no harm will be done by 
using 3/4-inch round tubing. Beneath the floor of the driver's cockpit 
in the fuselage is the warping frame, the support for the wires which 
truss the rear wing beams and also control the warping.

This frame is built up of four 3/4-inch, 20-gauge steel tubes, each 
about 3 feet long, forming an inverted, 4-sided pyramid. The front 
and back pairs of tubes are fastened to the lower fuselage beams with 
3/16-inch bolts at points 15 inches front and back of the horizontal 
strut. At their lower ends the tubes are joined by a fixture which 
carries the pulleys for the warping wires and the lever by which the 
pulleys are turned. In the genuine Bleriot, this fixture is a special 
casting. However, a very neat connection can be made with a piece 
of 1/16-inch steel stock, 1 1/4 by 6 inches, bent into a **U**-shape with the 
legs 1 inch apart inside. The flattened ends of the tubes are riveted 
and brazed to the outside upper corners of the **U**, and a bolt to carry 
the pulleys passes through the lower part, high enough to give 
clearance for 2-inch pulleys. This frame needs no diagonal wires. 

**Running Gear**. Passing now to the running gear, the builder 
will encounter the most difficult part of the entire machine, and it is 
impossible to avoid the use of a few special castings. The general 
plan of the running gear is shown in the drawing of the complete 
machine. Figs. 23 and 24, while some of the details are illustrated 
in Fig. 27, and the remainder are given in the detail sheet, Fig. 28. 
It will be seen that each of the two wheels is carried in a double fork, 
the lower fork acting simply as a radius rod, while the upper fork is 
attached to a slide which is free to move up and down on a 2-inch 
steel tube. This slide is held down by two tension springs, consisting 
of either rubber tubes or steel coil springs, which absorb the shocks 
of landing. The whole construction is such that the wheels are free 
to pivot sideways around the tubes, so that when landing in a 
quartering wind the wheels automatically adjust themselves to the direction 
of the machine. 

.. figure:: images/Image34.jpg
   :figclass: white-space-pre-line
   :align: center
   :scale: 85 %
   :alt: A FRENCH DEVELOPMENT OF THE WRIGHT MACHINE BUILT UNDER THE WRIGHT PATENTS
   
   A FRENCH DEVELOPMENT OF THE WRIGHT MACHINE BUILT UNDER THE WRIGHT PATENTS
   There is Little Resemblance to the Original Except in Wing Form and Warping

*Framework*. The main framework of the running gear consists 
of two horizontal beams, two vertical struts, and two vertical tubes. 
The beams are of ash, 4 3/4 inches wide in the middle half, tapering to 
3 3/4 inches at the ends, and 5 feet 2 3/4 inches long overall. The upper 
beam is H inch thick and the lower 1 inch. The edges of the beams 
are rounded off except at the points where they are drilled for bolt 
holes for the attachment of other parts. The two upper beams of 
the fuselage rest on these beams and are secured to them by two 
3/16-inch bolts each. 

The vertical struts are also of ash, 1 3/16 inch by 3 inches and 
4 feet 2 inches long overall. They have tenons at each end which fit 
into corresponding square holes in the horizontal beams. The two 
lower fuselage beams are fastened to these struts by two 3/16-inch 
through bolts and steel angle plates formed from 1/16-inch sheet steel. 
The channel section member across the front sides of these struts is 
for the attachment of the motor, and will be taken up later. The 
general arrangement at this point depends largely on what motor is 
to be used, and the struts should not be rounded or drilled for bolt 
holes until this has been decided. 

From the lower ends of these struts *CC*, Fig. 27, diagonal struts 
*DD* run back to the fuselage. These are of ash, 1 3/16 by 2 1/2 inches 
and 2 feet inches long. The rear ends of the struts *DD* are fastened 
to the fuselage beams by the projecting ends of the **U**-bolts of the 
horizontal fuselage struts, and also by angle plates of sheet steel. 
At the lower front ends the struts *DD* are fastened to the struts *CC* 
and the beam *E* by steel angle plates, and the beam is reinforced by 
other plates on its under side. 

*Trussing*. In the genuine Bleriot, the framework is trussed by 
a single length of steel tape, 1 1/8 by 1/16 inch and about 11 feet long, 
fastened to U-bolts in the beam *A*, Fig. 27. This tape runs down 
one side, under the beam *E*, and up the other side, passing through 
the beam in two places, where suitable slots must be cut. The tape 
is not made in this country, but must be imported at considerable 
expense. Ordinary sheet steel will not do. If the tape can not be 
obtained, a good substitute is 1/8-inch cable, which then would be made 
in two pieces and fastened to eye bolts at each end. 

.. figure:: images/Image35.jpg
   :figclass: white-space-pre-line
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   :scale: 85 %
   :alt: Fig. 27. Details of Bleriot Running Gear
   
   Fig. 27. Details of Bleriot Running Gear

.. figure:: images/Image36.jpg
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   :align: center
   :scale: 85 %
   :alt: Fig. 28. Details of Various Fittings for Bleriot Monoplane
   
   Fig. 28. Details of Various Fittings for Bleriot Monoplane

The two steel tubes are 2 inches in diameter, 18-gauge, and about 
4 feet 10 inches long. At their lower ends they are flattened, but 
cut away so that a 2-inch ring will pass over them. To these 
flattened ends are attached springs and wires which run from each tube 
across to the hub of the opposite wheel. The purpose of these is 
simply to keep the wheels normally in position behind the tubes. 
The tubes, it will be noticed, pass through the lower beam, but are 
sunk only 1/8 inch into the upper beam. They are held in place by 
sheet-steel sockets on the lower side of the upper beam and the upper 
side of the lower beam. The other sides of the beams are provided 
with flat plates of sheet steel. The genuine Bleriot has these sockets 
stamped out of sheet steel, but as the amateur builder will not have 
the facilities for doing this, an alternative construction is given here. 

In this method, the plates are cut out to pattern, the material 
being sheet steel 1/16 inch thick, and a 1/2-inch hole drilled through the 
center, a 2-inch circle then being drawn around this. Then, with a 
cold chisel a half dozen radial cuts are made between the hole and 
the circle. Finally this part of the plate is heated with a blow-torch 
and a 2-inch piece of pipe driven through, bending up the triangular 
corners. These bent up corners are then brazed to the tubes, and a 
strip of light sheet steel is brazed on to cover up the sharp edges. 
Of course, the brazing should not be done until the slides *GG*, Figs. 
27 and 28, have been put on. When these are once in place, they 
have to stay on and a breakage of one of them, means the 
replacement of the tube as well. This is a fault of the Bleriot design that 
can not well be avoided. It should be noticed that the socket at the 
upper end, as well as its corresponding plate on the other side of the 
beam, has extensions which reinforce the beam where the eye bolts 
or **U**-bolts for the attachment of the steel tape pass through. 

*Forks*. Next in order are the forks which carry the wheels. 
The short forks *JJ*, Figs. 27 and 28, which act simply as radius 
rods, are made of 1- by 3/8-inch oval tubing, a stock size which was 
specified for the overhead truss frame. It will be noticed that these 
are in two parts, fastened together with a bolt at the front end. 
The regular Bleriot construction calls for forged steel eyes to go in 
the ends of tubes, but these will be hard to obtain. The construction 
shown in the drawings is much simpler. The ends of the tubes are 
heated and flattened until the walls are about 1/16 inch apart inside. 
Then a strip of 1/16-inch sheet steel is cut the right width to fit in the 
flattened end of the tube, and brazed in place. The bolt holes then 
pass through the combined thickness of the tube and the steel strip, 
giving a better bearing surface, which may be further increased by 
brazing on a washer. 

The long forks *FF*, which transmit the landing shocks to the 
springs, are naturally made of heavier material. The proper size 
tubing for them is 1 1/8 by 5/8 inches, this being the nearest equivalent 
to the 14 by 28 mm French tubing. However, this is not a stock 
size in this country and can only be procured by order, or it can 
be made by rolling out 15/16-inch round tubing. If the oval tubing 
can not be secured, the round can be employed instead, other parts 
being modified to correspond. The ends are reinforced in the same 
way as described for the small forks. 

These forks are strengthened by aluminum clamps *H*, Figs. 27 
and 28, which keep the tubes from spreading apart. Here, of 
course, is another call for special castings, but a handy workman 
may be able to improvise a satisfactory substitute from sheet steel. 
On each tube there are four fittings: At the bottom, the collar *M* 
to which the fork *J* is attached, and above, the slide *G* and the clamps 
*K* and *L*, which limit its movement. The collar and slide should be 
forged, but as this may be impossible, the drawings have been 
proportioned for castings. The work is simple and may be done by the 
amateur with little experience. The projecting studs are pieces of 
3/4-inch, 14-gauge steel tubing screwed in tight and pinned, though if 
these parts be forged, the studs should be integral. 

The clamps which limit the movement of the slides are to be 
whittled out of ash or some other hard wood. The upper clamp is 
held in place by four bolts, which are screwed up tight; but when 
the machine makes a hard landing the clamp will yield a little and 
slip up the tube, thus deadening the shock. After such a landing, 
the clamps should be inspected and again moved down a bit, if 
necessary. The lower clamps, which, of course, only keep the wheels 
from hanging down too far, have bolts passing clear through the tubes. 

To the projecting lugs on the slides *GG* are attached the rubber 
tube springs, the lower ends connecting with eye bolts through the 
beam *E*. These rubber tubes, of which four will be needed, are being 
made by several companies in this country and are sold by supply 
houses. They should be about 14 inches long, unstretched, and 
1 1/4 inches in diameter, with steel tips at the ends for attachment. 

*Hub Attachments*. The hubs of the two wheels are connected 
with the link *P*, with universal joints *N N* at each end. In case the 
machine lands while drifting sidewise, the wheel which touches the 
ground first will swing around to head in the direction in which the 
machine is actually moving, and the link will cause the other wheel 
to assume a parallel position; thus the machine can run diagonally 
on the ground without any tendency to upset. 

This link is made of the same 1- by 3/8-inch oval tubing used 
elsewhere in the machine. In the original Bleriot, the joints are 
carefully made up with steel forgings. But joints which will serve 
the purpose can be improvised from a 1-inch cube of hard wood and 
three steel straps, as shown in the sketch, Fig. 27. From each of 
these joints a wire runs diagonally to the bottom of the tube on the 
other side, with a spring which holds the wheel in its normal position. 
This spring should be either a rubber tube, like those described above, 
but smaller, or a steel coil spring. In the latter case, it should be 
of twenty 3/4-inch coils of No. 25 piano wire. 

*Wheels*. The wheels are regularly 28 by 2 inches, corresponding 
to the 700 by 50 mm French size, with 30 spokes of 12-gauge wire. 
The hub should be 5 1/4 inches wide, with a 5/8-inch bolt. Of course, 
these sizes need not be followed exactly, but any variations will 
involve corresponding changes in the dimensions of the forks. The 
long fork goes on the hub inside of the short fork, so that the inside 
measurement of the end of the big fork should correspond to the 
width of the hub, and the inside measurement of the small fork 
should equal the outside measurement of the large fork. 

*Rear Skid*. Several methods are employed for supporting the rear 
end of the fuselage when the machine is on the ground. The first 
Bleriot carried a small wheel in a fork provided with rubber springs, the 
same as the front wheels. The later models, however, have a double 
**U**-shaped skid, as shown in Figs. 23 and 24. This skid is made of 
two 8-foot strips of ash or hickory 1/2 by 3/4 inches, steamed and bent 
to the **U**-shape as shown in the drawing of the complete machine. 

.. figure:: images/Image37.jpg
   :figclass: white-space-pre-line
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   :scale: 85 %
   :alt: Fig. 29. Details of Framework of Bleriot Main Supporting Planes
   
   Fig. 29. Details of Framework of Bleriot Main Supporting Planes

**Wings**. Having completed the fuselage and running gear, the 
wings are next in order. These are constructed in a manner which 
may seem unnecessarily complicated, but which gives great strength 
for comparatively little weight. Each wing contains two stout ash 
beams which carry their share of the weight of the machine, and 
12 ribs which give the proper curvature to the surfaces and at the 
same time reinforce the beams. These ribs in turn are tied together 
and reinforced by light strips running parallel to the main beams. 

.. figure:: images/Image38.jpg
   :figclass: white-space-pre-line
   :align: center
   :scale: 85 %
   :alt: Fig. 30. Complete Rib of Bleriot Wing and Pattern from Which Web Is Cut 
   
   Fig. 30. Complete Rib of Bleriot Wing and Pattern from Which Web Is Cut 

In the drawing of the complete wing. Fig. 29, the beams are 
designated by the letters *B* and *E*. *A* is a sheet aluminum member 
intended to hold the cloth covering in shape on the front edge. *C*, *D*, 
and *F* are pairs of strips (one strip on top, the other underneath) 
which tie the ribs together. *G* is a strip along the rear edge, and *H* 
is a bent strip which gives the rounded shape to the end of the wing. 
The ribs are designated by the numbers 1 to 12 inclusive. 

*Ribs*. The first and most difficult operation is to make the ribs. 
These are built up of a spruce board 3/16 inch thick, cut to shape on 
a jig saw, with 3/16- by 5/8-inch spruce strip stacked and glued to the 
upper and lower edges. Each rib thus has an I-beam section, such 
as is used in structural steel work and automobile front axles. Each 
of the boards, or webs as they are usually called, is divided into three 
parts by the main beams which pass through it. Builders sometimes 
make the mistake of cutting out each web in three pieces, but this 
makes it very difficult to put the rib together accurately. Each web 
should be cut out of a single piece, as shown in the detail drawing. 
Fig. 30, and the holes for the beams should be cut in after the top 
and bottom strips have been glued on. 

The detail drawing, Fig. 30, gives the dimensions of a typical 
rib. This should be drawn out full size on a strip of tough paper, 
and then a margin of 3/16 inch should be taken off all round except at 
the front end where the sheet aluminum member *A* goes on. This 
allows for the thickness of the top and bottom strips. In preparing 
the pattern for the jig saw, the notches for strips *C*, *D*, and *F* should 
be disregarded; neither should it be expected that the jig-saw 
operator will cut out the oval holes along the center of the web, 
which are simply to lighten it. The notches for the front ends of the 
top and bottom strips should also be smoothed over in the pattern. 

When the pattern is ready, a saw or planing mill provided with 
a saw suitable for the work, should cut out the 40 ribs (allowing a 
sufficient number for defective pieces and breakage) for about $2. 
The builder then cuts the notches and makes the oval openings with 
an auger and keyhole saw. Of course, these holes need not be 
absolutely accurate, but at least 3/4 inch of wood should be left all 
around them. 

Nine of the twelve ribs in each wing are exactly alike. No. 1, 
which forms the inner end of the wing, does not have any holes cut 
in the web, and instead of the slot for the main beam *B*, has a 1 3/4-inch 
round hole, as the stub end of the beam is rounded to fit the socket 
tube. (See Fig. 23.) Rib No. 11 is 5 feet 10 1/2 inches long, and No. 12 
is 3 feet long. These can be whittled out by hand, and the shape for 
them will be obvious as soon as the main part of the wing is put 
together. 

The next step is to glue on the top and bottom strips. The 
front ends should be put on first and held, during the drying, in a 
screw clamp, the ends setting close up into the notches provided for 
them. Thin 1/2-inch brads should be driven in along the top and 
bottom at 1- to 2-inch intervals. The rear ends of the strips should 
be cut off to the proper length and whittled off a little on the inside, 
so that there will be room between them for the strip *G*, 1/4 inch thick. 
Finally, cut the slots for the main beams, using a bit and brace and 
the keyhole saw, and the ribs will be ready to assemble. 

*Beams and Strips*. The main beams are of ash, the front beam 
in each wing being 3 1/4 by 3/4 inches and the rear beam 2 1/2 by 5/8 inches. 
They are not exactly rectangular but must be planed down slightly 
on the top and bottom edges, so that they will fit into the 
irregularly-shaped slots left for them in the ribs. The front beams, as mentioned 
above, have round stubs which fit into the socket tube on the 
fuselage. These stubs may be made by bolting short pieces of ash board 
on each side of the end of the beam and rounding down the whole. 

To give the wings their slight inclination, or dihedral angle, 
which will be apparent in the front view of the machine, the stubs 
must lie at an angle of 2 1/2 degrees with the beam itself. This angle 
should be laid out very carefully, as a slight inaccuracy at this point 
will result in a much larger error at the tips. The rear beams project 
about 2 inches from the inner ribs. The ends should be reinforced 
with bands of sheet steel to prevent splitting, and each drilled with 
a 3/8-inch hole for the bolt which attaches to the fuselage strut. A 
strip of heavy sheet steel should be bent to make an angle washer 
to fill up the triangular space between the beam and the strut; the 
bolt hole should be drilled perpendicularly to the beam, and not to 
the strut. The outer ends of the beams, beyond rib No. 10, taper 
down to 1 inch deep at the ends. 

The aluminum member *A*, Fig. 29, which holds the front edge 
of the wing in shape, is made of a 4-inch strip of fairly heavy sheet 
aluminum, rolled into shape round a piece of half-round wood, 2 1/4 
inches in diameter. As sheet aluminum usually comes in 6-foot 
lengths, each of these members will have to be made in two sections, 
joined either by soldering (if the builder has mastered this difficult 
process) or by a number of small copper rivets. 

No especial difficulties are presented by the strips, *C*, *D*, and *F*, 
which are of spruce 3/16 by 5/8 inch, or by the rear edge strip *G*, of spruce 
1/4 by 1 1/2 inches. Each piece *H* should be 1 by 1/2 inch half-round 
spruce, bent into shape, fitted into the aluminum piece at the front, 
and at the rear flattened down to 1/4 inch and reinforced by a small 
strip glued to the back, finally running into the strip *G*. The exact 
curve of this piece does not matter, provided it is the same on both 
wings. 

*Assembling the Wings*. Assembling the wings is an operation 
which demands considerable care. The main beams should first be 
laid across two horses, set level so that there will be no strain on the 
framework as it is put together. Then the 12 ribs should be slipped 
over the beams and evenly spaced 13 inches apart to centers, care 
being taken to see that each rib stands square with the beams, Fig. 31. 
The ribs are not glued to the beams, as this would make repairs 
difficult, but are fastened with small nails. 

Strips *C*, *D*, and *F*, Fig, 29, are next put in place, simply being 
strung through the rows of holes provided for them in the ribs, and 
fastened with brads. Then spacers of 3/16-inch spruce, 2 or 3 inches 
long, are placed between each pair of strips halfway between each 
rib, and fastened with glue and brads. This can be seen in the 
broken-off view of the wing in the front view drawing, Fig. 23. 
The rear edge strip fits between the ends of the top and bottom 
strips of the ribs, as mentioned above, fastened with brads or with 
strips of sheet-aluminum tacked on. 

.. figure:: images/Image39.jpg
   :figclass: white-space-pre-line
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   :alt: Fig. 31. Assembling the Main Planes of a Bleriot Monoplane 
   
   Fig. 31. Assembling the Main Planes of a Bleriot Monoplane 

Each wing is trussed by eight wires, half above and half below; 
half attached to the front and half to the rear beam. In the genuine 
Bleriot steel tape is used for the lower trussing of the main beams, 
similar to the tape employed in the running gear, but American 
builders prefer to use 1/8-inch cable. The lower rear trussing should 
be 3/32- or 7/64-inch cable, and the upper trussing 3/32-inch. 

The beams are provided with sheet-steel fixtures for the 
attachment of the cables, as shown in the broken-off wing view, Fig. 23. 
These are cut from fairly-heavy metal, and go in pairs, one on each 
side of the end beam, fasten with three 3/16-inch bolts. They have 
lugs top and bottom. They are placed between the fifth and sixth 
and ninth and tenth ribs on each side. 

To resist the backward pressure of the air, the wings are trussed 
with struts of 1-inch spruce and 1/16-inch cable, as shown in Fig. 23. 
The struts are placed between the cable attachments, being provided 
with ferrules of flattened steel tubing arranged to allow the rear beam 
freedom to swing up and down. The diagonal cables are provided 
with turnbuckles and run through the open spaces in the ribs. 

**Control System**. The steering gear and tail construction of the 
Bleriot are as distinctive as the swiveling wheels and the **U**-bolts, and 
the word "cloche" applied to the bell-like attachment for the control 
wires, has been adopted into the international vocabulary of 
aeroplaning. The driver has between his knees a small steering wheel 
mounted on a short vertical post. This wheel does not turn, but 
instead the post has a universal joint at the bottom which allows it 
to be swung backward and forward or to either side. The post is 
really a lever, and the wheel a handle. Encircling the lower part of 
the post is a hemispherical bell—the cloche—with its bottom edge on 
the same level as the universal joint. 

Four wires are attached to the edge of the cloche. Those 
at the front and back are connected with the elevator, and those at 
the sides with the wing-warping lever. The connections are so 
arranged that pulling the wheel back starts the machine upward, 
while pushing it forward causes it to descend, and pulling to either 
side lowers that side and raises the other. The machine can be kept 
on a level keel by the use of the wheel and cloche alone; the aviator 
uses them just as if they were rigidly attached to the machine, and 
by them he could move the machine bodily into the desired position. 

In practice, however, it has been found that lateral stability can 
be maintained more easily by the use of the vertical rudder than by 
warping. This is because the machine naturally tips inward on a 
turn, and, consequently, a tip can be corrected by a partial turn in 
the other direction. If, for example, the machine tips to the right, 
the aviator steers slightly to the left, and the machine comes back 
to a level keel without any noticeable change in direction. Under 
ordinary circumstances this plan is used altogether, and the warping 
is used only on turns and in bad weather. 

It will be noticed that the Bleriot control system is almost 
identical with that of the Henri Farman biplane, the only difference 
being that in the Farman the cloche and wheel are replaced by a 
long lever. The movements, however, remain the same, and as there 
are probably more Bleriot and Farman machines in use than all other 
makes together, this control may be regarded almost as a standard. 
It is not as universal as the steering wheel, gear shift, and brake 
levers of the automobile, but still it is a step in the right direction. 

.. figure:: images/Image40.jpg
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   :alt: Fig. 32. Control Device of Steel Tubing instead of Bleriot "Cloche"
   
   Fig. 32. Control Device of Steel Tubing instead of Bleriot "Cloche"

In the genuine Bleriot, the cloche is built up of two bells, one 
inside the other, both of sheet aluminum about 1/16 inch thick. The 
outer bell is 11 inches in diameter and 3 1/2 inches deep, and the inner 
one 10 inches in diameter and 2 inches deep. A ring of hard wood 
is clamped between their edges and the steering column, an aluminum 
casting passing through their centers. This construction is so 
complicated and requires so many special castings and parts that it is 
almost impossible for the amateur. 

*Steering Gear*. While not so neat, the optional construction 
shown in the accompanying drawing, Fig. 32, is equally effective. 
In this plan, the cloche is replaced by four **V**-shaped pieces of 1/2-inch, 
20-gauge steel tubing, attached to a steering post of 1-inch, 20-gauge 
tubing. At the lower end, the post has a fork, made of pieces of 
smaller tubing bent and brazed into place, and this fork forms part 
of the universal joint on which the post is mounted. The cross of 
the universal joint, which is somewhat similar to those employed on 
automobiles, can best be made of two pieces of heavy tubing, 1/2 inch 
by 12 gauge, each cut half away at the middle. The two pieces are 
then fastened together by a small bolt and brazed for greater security. 
The ends which are to go into the fork of the steering post must then 
be tapped for 3/8-inch machine screws. The two other ends of the 
cross are carried on **V**'s of 1/2-inch, 20-gauge tubing, spread far enough 
apart at the bottom to make a firm base, and bolted to the floor of 
the cockpit. 

The steering wheel itself is comparatively unimportant. On 
the genuine Bleriot it is a solid piece of wood 8 inches in diameter, 
with two holes cut in it for hand grips. On the post just under the 
wheel are usually placed the spark and throttle levers. It is rather 
difficult, however, to arrange the connections for these levers in such 
a way that they will not be affected by the movements of the post, 
and for this reason many amateur builders place the levers at one 
side on one of the fuselage beams. 

From the sides of the cloche, or from the tubing triangles which 
may be substituted for it, two heavy wires run straight down to the 
ends of the warping lever. This lever, together with two pulleys, 
is mounted at the lower point of the warping frame already described. 
The lever is 12 inches long, 11 inches between the holes at its ends, 
and 2 inches wide in the middle; it should be cut from a piece of 
sheet steel about 1/16 inch thick. The pulleys should be 2 1/2 inches in 
diameter, one of them bolted to the lever, the other one running 
free. The wires from the outer ends of the rear wing beams are 
joined by a piece of flexible control cable, which is given a single 
turn over the free pulley. The inner wires, however, each have a 
piece of flexible cable attached to their ends, and these pieces of 
cable, after being given a turn round the other pulley, are made fast 
to the opposite ends of the warping lever. These cables should be 
run over the pulleys, not under, so that when the cloche is pulled 
to the right, the left wing will be warped downward. 

It is a common mistake to assume that both pulleys are fastened 
to the warping lever; but when this is done the outer wire slackens 
off and does not move in accord with the inner wire, on account of 
the different angles at which they work. 

*Foot Levers*. The foot lever for steering is cut from a piece of 
wood 22 inches long, hollowed out at the ends to form convenient 
rests for the feet. The wires connecting the lever to the rudder may 
either be attached to this lever direct, or, if a neater construction is 
desired, they may be attached to another lever under the floor of the 
cockpit. In the latter case, a short piece of 1-inch steel tubing serves 
as a vertical shaft to connect the two levers, which are fastened to 
the shaft by means of aluminum sockets such as may be obtained 
from any supply house. The lower lever is 12 inches long and 2 
inches wide, cut from 1/16-inch steel similar to the warping lever. 

Amateur builders often cross the rudder wires so that pressing 
the lever to the right will cause the machine to steer to the left. 
This may seem more natural at first glance, but it is not the Bleriot 
way. In the latter, the wires are not crossed, the idea being to 
facilitate the use of the vertical rudder for maintaining lateral 
equilibrium. With this arrangement, pressing the lever with the foot on 
the high side of the machine tends to bring it back to an even keel. 

*Tail and Elevator*. The tail and elevator planes are built up 
with ribs and tie strips in much the same manner as the wings. 
However, it will hardly pay to have these ribs cut out on a jig saw 
unless the builder can have this work done very cheaply. It serves 
the purpose just as well to clamp together a number of strips of 
3/16-inch spruce and plane them down by hand. The ribs when 
finished should be 24 1/4 inches long. The greatest depth of the curve 
is 1 1/4 inches, at a point one-third of the way back from the front 
edge, and the greatest depth of the ribs themselves 2 1/4 inches, at the 
same point. Sixteen ribs are required. 

A steel tube 1 inch by 20 gauge, *C*, Fig. 33, runs through both 
tail and elevators, and is the means of moving the latter. Each rib 
at the point where the tube passes through, is provided with an 
aluminum socket. Those on the tail ribs act merely as bearings 
for the tube, but those on the elevator ribs are bolted fast, so that 
the elevators must turn with the tube. At its center the tube carries 
a lever *G*, of 1/16-inch steel 12 by 2 inches, fastened on by two aluminum 
sockets, one on each side. From the top of the lever a wire runs to 
the front side of the cloche, and from the bottom a second wire runs 
to the rear side of the cloche. 

.. figure:: images/Image41.jpg
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   :alt: Fig. 33. Construction Details of Bleriot Tail, Elevators, and Rudder
   
   Fig. 33. Construction Details of Bleriot Tail, Elevators, and Rudder

.. figure:: images/Image42.jpg
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   :alt: AN OLD DUTCH WINDMILL AND A MODERN FRENCH AEROPLANE
   
   AN OLD DUTCH WINDMILL AND A MODERN FRENCH AEROPLANE
   *This Photograph Protected By International Copyright*

.. figure:: images/Image43.jpg
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   :alt: VIEW OF THE R. E. P. MOTOR AND LANDING GEAR
   
   VIEW OF THE R. E. P. MOTOR AND LANDING GEAR
   This Machine is the Work of One of the Cleverest Aeroplane Designers in Europe

The tube is carried in two bearings *HH*, attached to the lower 
beams of the fuselage. These are simply blocks of hard wood, 
fastened by steel strips and bolts. The angle of incidence of the 
tail is adjustable, the tail itself being held in place by two vertical 
strips of steel rising from the rear edge and bolted to the fuselage, 
as shown in the drawing, Fig. 33. To prevent the tail from folding 
up under the air pressure to which it is subjected, it is reinforced 
by two 3/4-inch, 20-gauge steel tubes running down from the upper 
sides of the fuselage, as shown in the drawing of the complete machine,
Fig. 23. 

The tail and elevators have two pairs of tie strips, *B* and *D*, 
Fig. 33, made of 3/16- by 5/8-inch spruce. The front edge *A* is half 
round, 1- by 1/2-inch spruce, and the rear edge *E* is a spruce strip 
1/4- by 1 1/2-inches. The end pieces are curved. 

*Rudder*. The rudder is built up on a piece of 1-inch round 
spruce *M*, corresponding in a way to the steel tube used for the 
elevators. On this are mounted two long ribs *KK*, and a short rib 
*J*, made of spruce 3/8 inch thick and 1 3/8 inches wide at the point where 
*M* passes through them. They are fastened to *M* with 1/8-inch through 
bolts. The rudder lever *N*, of 1/16-inch steel, 12 by 2 inches, is laid 
flat on *J* and bolted in place; it is then trussed by wires running 
from each end to the rear ends of *KK*. From the lever other wires 
also run forward to the foot lever which controls the rudder. 

The wires to the elevator and rudder should be of the flexible 
cable specially made for this purpose, and should be supported by 
fairleaders attached to the fuselage struts. Fairleaders of different 
designs may be procured from supply houses, or may be improvised. 
Ordinary screw eyes are often used, or pieces of copper tubing, bound 
to the struts with friction tape. 

**Covering the Planes**. Covering the main planes, tail, elevators, 
and rudder may well be left until the machine is otherwise ready 
for its trial trip, as the cloth will not then be soiled by the dust and 
grime of the shop. The cloth may be any of the standard brands
which are on the market, preferably in a rather light weight made 
specially for double-surfaced machines of this type; or light-weight 
sail cloth may be used, costing only 25 or 30 cents a yard. About 
80 yards will be required, assuming a width of 36 inches. 

.. figure:: images/Image44.jpg
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   :alt: Fig. 34. Method of Mounting Fabric on Main Supporting Frame
   
   Fig. 34. Method of Mounting Fabric on Main Supporting Frame

Except on the rudder, the cloth is applied on the bias, the idea 
being that with this arrangement the threads act like diagonal truss 
wires, thus strengthening and bracing the framework. When the 
cloth is to be put on in this way it must first be sewed together in 
sheets large enough to cover the entire plane. Each wing will require 
a sheet about 14 feet square, and two sheets each 6 feet square will 
be required for the elevators and tail. The strips of cloth run 
diagonally across the sheets, the longest strips in the wing sheets 
being 20 feet long. 

Application of the cloth to the wings, Fig. 34, is best begun 
by fastening one edge of a sheet to the rear edge of the wing, 
stretching the cloth as tight as can be done conveniently with one hand. 
The cloth is then spread forward over the upper surface of the wing 
and is made fast along the inner end rib. Small copper tacks are 
used, spaced 2 inches apart on the upper side and 1 inch on the 
lower side. After the cloth has been tacked to the upper sides of 
all the ribs, the wing is turned over and the cloth stretched over 
the lower side. Finally the raw edges are trimmed off and covered 
with light tape glued down, tape also being glued over all the rows 
of tacks along the ribs, making a neat finish and at the same time 
preventing the cloth from tearing off over the tack heads. 

**Installation of Motor**. As stated previously, the ideal motor 
for a Bleriot-type machine is short along the crank shaft, as the 
available space in the fuselage is limited, and air-cooled for the same 
reason. Genuine Bleriots are always fitted with one of the special 
types of radial or rotary aeronautic motors, which are always 
air-cooled. Next in popularity to these is the two-cylinder, 
horizontal-opposed motor, either air- or water-cooled. However, successful 
machines have been built with standard automobile-type, 
four-cylinder, water-cooled motors, and with four-cylinder, two-cycle, 
aeronautic motors. 

When the motor is water-cooled, there will inevitably be some 
difficulty in finding room for a radiator of sufficient size. One scheme 
is to use twin radiators, one on each side of the fuselage, inside of 
the main frame of the running gear. Another plan is to place the 
radiator underneath the fuselage, using a supplementary water tank 
above the cylinders to facilitate circulation. These two seem to be 
about the only practicable arrangements, as behind the motor the 
radiator would not get enough air, and above it would obstruct the 
view of the operator. 

It is impossible to generalize to much effect about the method 
of supporting the motor in the fuselage, as this must differ with the 
motor. Automobile-type motors will be carried on two heavy ash 
beams, braced by lengths of steel tubing of about 1 inch diameter and 
16 gauge. When the seven-cylinder rotary Gnome motor is used, 
the crank shaft alone is supported; it is carried at the center of two 
X-shaped frames of pressed steel, one in front of and the other behind 
the motor. The three-cylinder Anzani motors are carried on four 
lengths of channel steel bent to fit around the upper and lower 
portions of the crank case, which is of the motorcycle type. 

Considerable care should be taken to prevent the exhaust from 
blowing back into the operator's face as this sometimes carries with 
it drops of burning oil, besides disagreeable smoke and fumes. The
usual plan is to arrange a sloping dashboard of sheet aluminum so 
as to deflect the gases down under the fuselage. 

The three sections of the fuselage back of the engine section are 
usually covered on the sides and bottom with cloth like that used 
on the wings. Sometimes sheet aluminum is used to cover the 
section between the wing beams. However, those who are just 
learning to operate machines and are a little doubtful about their 
landings often leave off the covering in order to be able to see the 
ground immediately beneath their front wheels. 

.. figure:: images/Image45.jpg
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   :alt: Fig. 35. Running Gear of Morane Type of Bleriot Monoplane 
   
   Fig. 35. Running Gear of Morane Type of Bleriot Monoplane 

**New Features**. *Morane Landing Gear*. Although the regular 
Bleriot landing gear already described, has many advantages and 
ha.s been in use with only detail changes for several years, some 
aviators prefer the landing gear of the new Morane monoplane, 
which in other respects closely resembles the Bleriot. This gear, 
Fig. 35, is an adaptation of that long in use on the Henri Farman 
and Sommer biplanes, combining skids and wheels with rubber-band 
springs. In case a wheel or spring breaks, whether due to a defect 
or to a rough landing, the skids often save an upset. Besides, the 
tension of the springs is usually such that on a rough landing the 
wheels jump up and allow the skids to take the shock; this also 
prevents the excessive rebound of the Bleriot springs under similar 
conditions. 

Another advantage which may have some weight with the 
amateur builder, is that the Morane running gear is much cheaper 
and easier to construct. Instead of the two heavy tubes, the four 
forks of oval tubing, and the many slides, collars, and blocks—most 
of them special forgings or castings—the Morane gear simply requires 
two short laminated skids, four ash struts, and some sheet steel. 

The laminated skids are built up of three boards each of 
5/8 by 2-inch ash, 3 1/2 feet long. These must be glued under heavy 
pressure in forms giving the proper curve at the front end. When 
they are taken from the press, three or four 1/2-inch holes should be 
bored at equal distances along the center line and wood pins driven 
in; these help in retaining the curve. The finished size of the skids 
should be 1 3/4 by 1 3/4 inches. 

Four ash struts 1 1/4 by 2 1/2 inches support the fuselage. They 
are rounded off to an oval shape except at the ends, where they 
are attached to the skids and the fuselage beams with clamps of 
1/16 inch sheet steel. The ends of the struts must be beveled off 
carefully to make a good fit; they spread out 15 degrees from the 
vertical, and the rear pair have a backward slant of 30 degrees from 
vertical. 

Additional fuselage struts must be provided at the front end of 
the fuselage to take the place of the struts and beams of the Bleriot 
running gear. The two vertical struts at the extreme front end may 
be of the same 1 1/4- by 2 1/2-inch ash used in the running gear, planed 
down to 1 3/16 inches thick to match the thickness of the fuselage 
beams. The horizontal struts should be 1 3/16 by 1 3/4 inches. 

The wheels run on the ends of an axle tube, and usually have 
plain bearings. The standard size bore of the hub is 15/16 inch, and 
the axle tube should be 15/16 inch diameter by 11 gauge. The tube 
also has loosely mounted on it two spools to carry the rubber band 
springs. These are made of 2 1/4-inch lengths of 1 3/8-inch tubing, with 
walls of sufficient thickness to make an easy sliding fit on the axle 
tube. To the ends of each length of tube are brazed 2 1/2-inch washers 
of 3/16 inch steel, completing the spool. 

The ends of the rubber bands are carried on rollers of 3/4-inch, 
16-gauge tubing, fastened to the skids by fittings bent up from 
3/16-inch sheet steel. Each fitting is bolted to the skid with two 
3/8-inch bolts. 

Some arrangement must now be made to keep the axle centered 
under the machine, as the rubber bands will not take any sidewise 
strain. A clamp of heavy sheet steel should be made to fit over the 
axle at its center, and from this heavy wires or cables run to the 
bottom ends of the forward struts. These wires may be provided 
with stiff coil springs, if it is desired to allow a little sidewise 
movement. 

.. figure:: images/Image46.jpg
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   :alt: Fig. 36. Details of Bleriot Inverse Curve Tail
   
   Fig. 36. Details of Bleriot Inverse Curve Tail

*New Bleriot Inverse Curve Tail*. Some of the latest Bleriot 
machines have a new tall which seems to add considerable to their 
speed. It consists of a fixed tail, Fig. 36, nearly as large as the 
old-style tail and elevators combined, with two elevator flaps hinged 
to its rear edge. The peculiarity of these elevators, from which the 
tail gets its name, is that the curve is concave above and convex 
below—at first glance seeming to have been attached upside down. 
In this construction, the 1-inch, 20-gauge tube, which formerly 
passed through the center of the tail, now runs along the rear edge, 
being held on by strips of 1/2- by 1/16-inch steel bent into **U**-shape 
and fastened with screws or bolts to the ribs. Similar strips attach 
the elevators to the tube, but these strips are bolted to the tube. 
The construction is otherwise like that previously described. It is 
said that fitting this tail to a Bleriot in place of the old-style tail 
adds 5 miles an hour to the speed, without any other changes being 
made. 

Another slight change which distinguishes the newer Bleriots is 
in the overhead frame, which now consists of a single inverted **V** 
instead of two **V**'s connected by a horizontal tube. The single **V** 
is set slightly back of the main wing beam, and is higher and, of 
course, of heavier tubing than in the previous construction. Its top 
should stand 2 feet 6 inches above the fuselage, and the tubing 
should be 1 inch 18 gauge. It also requires four truss wires, two 
running to the front end of the fuselage and two to the struts to 
which the rear wing beams are attached. All of the wires on the 
upper side of the wings converge to one point at the top of this **V**, 
the wires from the wing beams, of course, passing over pulleys. 

These variations from the form already described may be of 
interest to those who wish to have their machines up-to-date in 
every detail, but they are by no means essential. Hundreds of the 
old-style Bleriots are flying every day and giving perfect satisfaction. 

ART OF FLYING
#############

Knowledge of the science of aeronautics and ability to fly are 
two totally different things. Long-continued study of the problem 
from its scientific side enabled the Wright Brothers to learn how 
to build a machine that would fly, but it did not teach them how to 
fly with it. That came as the result of persistent attempts at 
flying itself. A study of the theoretic laws of balancing does not 
form a good foundation for learning how to ride a bicycle—practice 
with the actual machine is the only road to success. The best 
evidence of this is to be found in the fact that several of the most 
successful aviators today have but a slight knowledge of the science of 
aeronautics. They are not particularly well versed in what makes 
flight possible, but they know how to fly because they have learned 
it in actual practice. 

Reference to the early work of the Wright Brothers shows that 
during a period of several years they spent a large part of their time 
in actual experiments in the air, and it was not until these had proved
entirely satisfactory that they attempted to build a power-driven 
machine. 

**Methods Used in Aviation Schools**. Aviation schools are 
springing up all over this country and there are a number of well-established 
institutions of this kind abroad. In the course of instruction, the 
student must first learn the use of the various controls on a dummy 
machine. In the case of an English school, this dummy, Fig. 37, is 
a motorless aeroplane mounted on a universally-jointed support so 
as to swing about a pivot as desired. This is employed for the 
purpose of familiarizing the beginner with the means of maintaining 
equilibrium in the air. 

.. figure:: images/Image47.jpg
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   :alt: Fig. 37. Monoplane Dummy Used for Practice in Aviation School
   
   Fig. 37. Monoplane Dummy Used for Practice in Aviation School

.. figure:: images/Image48.jpg
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   :alt: Fig. 38. Aerocycle with Treadle Power for Practice Work
   
   Fig. 38. Aerocycle with Treadle Power for Practice Work

A French school, on the other hand, employs a wingless machine, 
which is otherwise complete, as it consists of a regulation chassis 
with motor and propeller, all steering and elevating controls. On 
this, the student may practice what has come to be familiarly known 
as "grass-cutting," to his heart's content, without any danger of 
the machine taking to the air unexpectedly, as has frequently been the 
case where first attempts have been made on a full-fledged machine. 
Usually, most of such attempts result disastrously, often destroying 
in a moment the result of months of work in building the machine. 

.. figure:: images/Image49.jpg
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   :alt: Fig. 39. Voisin Biplane with Double Control for Teaching Beginners
   
   Fig. 39. Voisin Biplane with Double Control for Teaching Beginners

A French aerocycle, Fig. 38, a comparatively inexpensive machine, 
is also useful for practice in balancing and in short, low flights. The 
French apparatus in question may accordingly be considered an 
advance, not only over the English machine, even of the type shown 
in Fig. 39, which has a double control, and is especially designed for 
the teaching of beginners, but very much over the practice of 
attempting to actually fly for the first time in a strange machine, as it 
provides the necessary practice in the handling of the motor and the 
lateral steering. The machine can make high speed over the ground,
but is perfectly safe for the beginner, as it is incapable of rising. 
Having gone through the stages represented by either of these 
contrivances, the best course for the learner to follow is to try gliding, 
taking short glides to attain the ability to quickly meet varying 
conditions of the atmosphere. 

The fact that these glides are of extremely short duration at first 
need not be discouraging when it is recalled that, after several years 
of work, the Wright Brothers considered that great progress had 
been made when, in 1902, they were able to make glides of 26 seconds. 
During six days of the practice season of that year, they made 375 
gliding flights of various distances, most of them comparatively 
short, but each one of value in familiarizing the glider with the 
conditions to be met. It is not material whether gliding or manipulation 
of the control levers is taken up first, as both should be mastered as 
far as possible before attempting to fly a regular machine. 

**Use of the Elevating Plane**. So many things are necessary to 
the control of an aeroplane that thinking becomes entirely too slow 
a process—the aviator must be endowed with something approaching 
the instinct of the bird; he must be so familiar with his machine and 
its peculiarities that a large part of the work of controlling it is the 
result of subconscious movement. The control levers of many 
machines are so arranged that this subconscious movement on the 
part of the aviator directly operates the balancing mechanism. 
There is no time to think. When a machine rises from the ground, 
facing the wind as it should, its path of flight should be a gradual 
upward inclination, this being something difficult to accomplish at 
first, owing to the sensitiveness of the elevating rudder, the tendency 
almost invariably being to give the latter too great an angle of 
incidence. At this stage, the maximum velocity of flight has not yet 
been attained and care must be taken to keep the angle of ascent 
small. Otherwise, the power of the engine, which may not have 
reached its maximum, would not be sufficient to cause the machine 
to ascend an inclined path at the starting speed. If the speed of 
flight be reduced by the increased resistance at this point, the whole 
machine will slide back in the air, and if a sudden gust of wind happens 
to coincide with the attempt to rise at too great an angle, there is 
danger of it being blown over backward. 

Where the machine is just leaving the ground and the elevator 
has been set at an excessive angle, the rear end of the skids or the 
tail may slap the ground hard and break off, or they will impose so 
much resistance upon its movement by scraping over the turf that 
the machine can not attain its soaring speed. It must be borne in 
mind, of course, that remarks such as the present can be only of the 
most general nature, every type of machine having its own 
peculiarities—in some instances, the extreme opposite of those characterizing 
similar machines. For example, in the Voisin 1910 type, the very 
large and powerful light tail tends to lift before the main planes, 
and if this be not counteracted, the whole machine may turn up on 
its end. In order to offset this tendency, the elevator must be raised 
so as to keep sufficient pressure beneath it; the moment of this 
pressure about the center of gravity must be at least equal to the pressure 
under the tail planes about the center of gravity of the machine, or 
the tail will rise unduly in the air. At least that is the theory of 
it—naturally, only practice with that particular machine would suffice 
to enable an aviator to familiarize himself with that particular 
peculiarity. Again, some machines are "tail heavy." But there is 
great difficulty in even approximating the degree of relative motion, 
for which reason it has been suggested, under "Accidents and Their 
Lessons," that a gradometer, or small spirit level, in plain sight of 
the aviator, should form part of the equipment of every machine. 
The Wrights long ago adopted the expedient of attaching a strip of 
ribbon to the elevator to provide an indication of motion relative 
to the wind. 

**Aeroplane in Flight**. The sensation of motion after the machine 
leaves the ground is almost imperceptible, and it is likewise extremely 
difficult to tell at just what moment the aeroplane ceases running 
on the solid ground and takes to the air. There is a feeling of 
exhilaration but very little of motion. Whereas 40 miles an hour over the 
ground, particularly in an automobile, brings with it a lively 
appreciation of the speed of travel, the same speed in an aeroplane is a 
very gentle motion when high above the ground. If there be no 
objects close at hand, with which to compare the speed, the sense of 
motion is almost entirely lost. 

**Center of Gravity**. The static balance of a machine should be 
carefully tried before commencing to fly, and particularly that of a 
biplane of the Wright type, in which the aviator sits behind the engine.
When provision is made for carrying a passenger, his seat is placed 
in the center line of the machine, so that his presence or absence 
does not materially affect the question of lateral balance. As men 
are not all of the same weight, in cases in which the aviator only 
partly balances the engine about the center line, his weight being 
insufficient for the purpose, extra weights should be placed on the 
wing tip at the lightest end until the true balance is secured, 
otherwise a permanent warping, or *gauchissement* as the French term it, 
is required at this side in order to keep the machine on an even keel. 
In other words, the machine will carry what sailors term a port helm 
where the left side of the machine is lighter than the right, and *vice 
versa*, and it will be necessary to keep the rudder over to that side 
slightly during the entire flight to counteract this tendency. 

In aeroplanes fitted with tails, the center of gravity is usually 
in the vicinity of the trailing edge of the main planes and, of course, 
should be on the center line of the machine. The center of gravity 
of the aviator on a monoplane should approximately coincide with 
that of the machine. If this be not the case, the stabilizers or the 
elevator must be permanently set to produce longitudinal balance. 
Much downward set, or the increase of the angle of incidence of the 
tail, will create undue resistance to flight and should be avoided when 
possible by bringing the weight farther forward. The center of 
pressure should coincide with the center of gravity, and balance will 
result. 

Before even ground work is attempted, the position of the 
center of gravity should be determined in the manner shown in Fig. 
40, the approximate location for four types of machines being shown. 
At what point the machine must be suspended, so that it can tip only 
frontward and backward and be evenly balanced, is a question that 
must be answered in order to ascertain the probability of the machine's 
pitching forward whenever mud, grass, or rough ground is 
encountered in alighting. If the center of gravity should lie in front of the 
axles of the ground wheels in a machine of the Farman type, trouble 
is sure to follow. Always consider the relation of the center of gravity 
to the wheels, in order that you may gain some idea of the 
distribution of the weight on the running gear when the machine is tipped 
forward 10 degrees. If the wheels are not forward far enough there 
will be trouble in running on the ground. The elevators must correct 
whatever variance there may be from the correct center of gravity 
and position of the wheels, and the manipulation of the elevators for 
that purpose requires skill. If the tail be very heavy, the elevator 
may not be able to counteract that defect. 

.. figure:: images/Image50.jpg
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   :alt: Fig. 40. Method of Determining Center of Gravity of Different Types of Machines 
   
   Fig. 40. Method of Determining Center of Gravity of Different Types of Machines 

The position of the center of gravity of a machine in regard to 
lateral stability in flight is a matter of far greater importance than 
untried aviators realize. Having it too low is quite as bad as too high, 
as in either case there is a tendency to upset. Although the dihedral 
angle is considered wasteful of power, it seems to do more to secure 
inherent stability than any other device. Devices for maintaining 
stability automatically are to be frowned upon in the present state 
of the art. The sensitive perception and quick response which come 
with intimate knowledge of a machine's peculiarities, are at present 
worth more than gyroscopes and pendulums. To acquire this 
intimate knowledge, the aviator must familiarize himself thoroughly 
with the machine; he must become so accustomed to controls that 
he and the machine are literally one. A practiced bicycle rider does 
not have to think about balance, neither does the practiced aviator, 
yet he must always be prepared to meet motor stoppages, unusual 
air disturbances, and breakages. A leap from the ground directly 
into the air, without preliminary practice, means certain accident, 
to put it mildly. 

**Center of Pressure**. But although the center of gravity remains 
approximately constant, the center of pressure is continually 
varying and is never constant for many seconds. The center of pressure 
on an aerocurve constructed to Phillips' design, Fig. 41, is about 
one-third of the chord from the leading edge of the plane under normal 
conditions, *i.e.*, when the angle of incidence is about 8 degrees between 
the direction of motion of the plane and that of the air. At the 
moment this angle is increased the center of pressure moves toward 
the rear, and *vice versa*. The center of gravity must be moved to 
coincide with this new position, or the center of pressure must be 
artificially restored by the use of supplementary planes or elevators, 
moving in a contrary direction. A forward movement of the center of 
pressure tends to lower the tail of the machine, when the intensity of 
the pressure is unchanged, and to counterbalance this the rear elevator 
must have its angle of incidence increased in order to increase the 
lift at the rear of the machine, or it will slide down backward. The 
alternative to be adopted in case of temporary lack of engine power 
is to decrease the angle of the elevator and allow the aeroplane to 
sweep downward, thus gaining momentum. The increase of speed 
will then be sufficient probably 
to enable the machine to 
continue in a horizontal flight, 
when the center of pressure is again restored to its normal position.

.. figure:: images/Image51.jpg
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   :alt: Fig. 41. Aerocurve of Phillip's Design
   
   Fig. 41. Aerocurve of Phillip's Design

**Ground Practice**. First of all, the aviator should familiarize 
himself with his seat for it is from that place that he must judge 
wind effects, vibration, motor trouble, and the thousand and one 
little creaks and hums that will ultimately mean so much to him. 
Not until he has thoroughly accustomed himself to his seat, should 
he try to run along the ground. This done, hours should be spent 
running up and down and around the field to learn the use of the 
rudder, particularly on rough ground. The runs should be straight 
so that when the time comes to leap into the air, the aviator may be 
sure that he is on an even keel, and flying straightaway. In order 
to prevent the possibility of leaving the ground unexpectedly in 
practice, trials should be made only in calm weather and with the 
motor well throttled down so that the machine will be reduced to a 
speed of not more than 15 miles per hour. After a time this may be 
increased to 20, but the latter is the maximum for ground practice, 
as the machine will rise at speeds slightly exceeding this. In these 
practice rims on the ground, the student should learn to gauge the 
rush of air against his face, as when aloft his best gauge will be the 
wind pressure on his cheeks, as that will tell him whether he is 
moving with sufficient speed to keep up or not. It will also tell him 
ultimately whether he is moving along the ground fast enough to leap up. 

.. figure:: images/Image52.jpg
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   :align: center
   :scale: 85 %
   :alt: VEDRINES, ONE OF THE MOST FAMOUS AND SUCCESSFUL OF EUROPEAN AEROPLANE PILOTS, SEATED IN A DEPERDUSSIN MONOPLANE
   
   VEDRINES, ONE OF THE MOST FAMOUS AND SUCCESSFUL OF EUROPEAN AEROPLANE PILOTS, SEATED 
   IN A DEPERDUSSIN MONOPLANE

.. figure:: images/Image53.jpg
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   :alt: AIRSHIP CROSSING ONE OF THE NATIONAL ROADS IN RURAL FRANCE
   
   AIRSHIP CROSSING ONE OF THE NATIONAL ROADS IN RURAL FRANCE
   *This Photograph Protected by International Copyright*

In this stage of experimenting on the ground, the elevator is 
kept neutral as far as possible. With increasing skill its use may be 
ventured, but only sparingly, for it takes very little to lift the machine 
from the ground with a speed in excess of 20 miles per hour. It will 
soon be discovered that the elevator can be used as a brake to 
prevent pitching forward. The tail elevators on the Farman or Bleriot 
running gear are very effective owing to the blast of the propeller, 
even when the main planes are not moving forward at lifting speed. 
With the Curtiss type of running gear and a front elevator only, 
it is often possible at 18 to 20 miles per hour to raise the front wheel 
off the ground for a second or two—facts which indicate that at 25 
to 28 miles per hour, the elevator is far more effective. 

**First Flight**. The first actual flight should be confined to a short 
trip parallel to the ground and not more than one or two feet above 
it. At first, the student should see how close he can fly to the ground 
without actually touching it, which he can do by gradually 
increasing his forward speed. This must be done in an absolute calm as an 
appreciable amount of wind will bring in too many other factors for 
the student to master at so early a stage. This practice should be 
continued in calm air until short, straight flights can be made a foot 
or two from the ground with the motor wide open. If it be found 
that the machine barely flies straightaway with the full power of the 
motor, the latter is either badly out of adjustment, or a more 
powerful engine is required. In an under-powered machine turning would 
be suicidal. Moreover, the resistance encountered in the air is 
greater than on the ground and may be such that the speed is not 
sufficient for sustentation. Fig. 42, (a) and (b), show why it is possible 
to run along the ground faster than it is possible to travel in the air, 
under certain conditions, and why the ground can be left at low 
speed. If it were possible to drive a machine with such enormous
projected areas as *BB*, shown in Fig. 42 (b), a man could fly slowly for 
an indefinite period. But the projected area is greater than the air 
displaced by the propeller, and it is impossible to fly except with a 
moderate angle of incidence, giving projected areas *A A*, Fig. 42 (a). 
The student, as he increases in skill, may venture to a height of 
10 feet, which should be maintained as accurately as before, and 
after making a run of 100 yards, the machine should be pointed 
down, but ever so slightly. The wind pressure on the face immediately 
becomes greater. Within a foot or two of the ground the motor 
should be cut off or throttled. This should be tried ten or fifteen 
times, and the height increased to 30 or 40 feet, in order that the 
student may familiarize himself with the sensation of coasting. At 
the end of each glide the machine will seem to become more responsive, 
as indeed it does, for gliding down greatly increases the efficiency 
of the elevator and other controls, because of the increased speed. 
Gliding down steep angles is often the aviator's salvation in a tight 
place, particularly when the motor fails, a side gust threatens or 
an air pocket is encountered. 

.. figure:: images/Image54.jpg
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   :alt: Fig. 42. Diagrams Showing Greater Projected Area of Main Plane when Running along Ground
   
   Fig. 42. Diagrams Showing Greater Projected Area of Main Plane when 
   Running along Ground

**Warping the Wings**. When sufficient confidence has been 
attained at a height of 30 to 40 feet, the ailerons or warping devices 
may be tried judiciously. Here the intention should be to correct 
any tendency to side tipping, and not purposely to incline the machine 
as far as possible without actually causing a wreck. The use of the 
lateral control may cause the machine to swerve a little, but that 
may be ignored. Before landing, a straight course should be taken 
so that the machine will always come down on an even keel. With 
increasing practice, the student may fly higher, but always with the 
understanding that there is a limit to the angle of incidence. An 
automobile is retarded when it strikes a short, steep hill; so is an 
aeroplane. No aeroplane has yet been built that can take a steep 
angle and climb right up that grade continuously. Altitude is
reached by a series of small steps and at comparatively low angles, 
as unless the course is straightened out at regular intervals, a machine 
will lose its speed and tend to plunge tail first, just as is the case when 
an attempt is made to rise from the ground at too sharp an angle. 

In warping the wings an increase of lift imparted to one wing 
of the machine is produced by increasing the angle of incidence of 
the whole or part of the wing, or by an increase of pressure under 
that wing, and will tend to cause that side of the machine to rise 
and the other side to lower, the result being that the machine will 
be liable to slide through the air diagonally. In the majority of 
aeroplanes there are no fins or keels to counteract this movement, 
and lateral stability must be restored by artificially increasing the 
lift of the depressed wing. This can be done by warping, or lowering 
the trailing edge of the depressed wing and increasing its lift, and 
simultaneously raising the trailing edge of the other wing, thus 
decreasing the angle of incidence of the latter and reducing its lifting 
effect. This applies to flight on a straight course, whatever the cause 
may be that tends to upset lateral stability. It will be seen, 
therefore, that the center of gravity remains constant and the center of 
pressure must be manipulated to restore stability. This 
manipulation is much more rapid and positive than the alteration of the center 
of gravity by the movement of the aviator's body resorted to in the 
early gliding flights of pioneer experimenters. 

**Making a Turn**. The first turn should be made over a large 
field and the diameter of the turn should be at least half a mile. The 
height should be not less than 50 feet. After that level has been 
maintained, the rudder should be moved very gingerly. The machine 
will lean in almost immediately, because the outer end travels at a 
higher speed than the inner and therefore has a greater lift. Warping 
or working the ailerons should be resorted to as a means of 
counteracting this tendency, and the rudder swung to the opposite 
direction, if necessary. It is obvious that if the rudder will cause the 
machine to bank when swung in one direction, it will right the machine 
again when swung in the opposite direction. It is even possible to 
turn the machine on an even keel by anticipating the banking, simply 
by correctly using the rudder, which was necessary in the old Voisin 
machine flown by Farman in 1908, because it had no mechanical 
lateral control. The student should learn the correct angle of 
banking, *i.e.* the angle at which the machine will neither skid nor slide 
down and which is most economical of power because it requires 
less use of the lateral controls. The necessity of "feeling the air" 
is greater in turning than in any other phase of flying. By "feeling 
the air" is meant the ability to meet any contingency intuitively 
and not until this is acquired can the student become an expert 
aviator. When it has been acquired, safe flying is assured and is 
dependent only upon the integrity of the planes, motor, and controls. 
By using the rudder discreetly and by banking simply far enough 
to partially offset the centrifugal force of turning, the use of the 
lateral control will not be necessary in still air. Even too short a 
turn can be corrected by a quick use of the rudder. 

The peculiarities existing between different types of 
monoplanes become even more marked than between the biplane and the 
monoplane. For example, in piloting a Bleriot monoplane, Fig. 
43, it is necessary to take into account the effect of the engine torque. 
As the engine rotates in a right-hand direction, from the point of 
view of the pilot, the left wing tends to rise in the air, owing to the 
depression of the right side of the machine. The machine also tends 
to turn to the right, and this must be counteracted by putting the 
rudder over to the left. An aeroplane answers its controls with 
comparative slowness, with the exception, perhaps, of the Wright machine, 
which is noted for its sensitive and quick response to every 
movement of the levers. All control movements must, therefore, be very 
gentle, as the behavior of an aeroplane is more like that of a boat 
than that of an automobile. The action of the elevator has already 
been described, and it is, perhaps, the most difficult of all the 
controls to manipulate, in that it requires the exercise of a new sense. 
The direction rudder is naturally a more familiar type of control, 
and in action is similar to the rudder of a boat. 

The torque of the motor renders it advisable for a novice to 
turn his machine to the right, if a right-hand propeller be used, and 
*vice versa*. If two propellers, turning in opposite directions, are 
employed, as in the Wright biplane, there is no inequality from the 
torque of the motor. Since torque is not noticeable in straight 
flying, straightening out again will always serve the student when he 
finds himself in trouble on a turn. When the use of the rudders 
and ailerons has reduced the speed, a downward glide will increase 
it again, and if the motor should stop on a turn, such a downward 
glide is immediately imperative. When the machine is thus gliding, 
a change in the fore-and-aft balance becomes at once apparent, 
because the blast of the propeller no longer acts on the tail, and the 
elevator must then be used with greater amplitude to obtain the 
same effect.
 
.. figure:: images/Image55.jpg
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   :alt: Fig. 43. Making a Start with Bleriot Monoplane
   
   Fig. 43. Making a Start with Bleriot Monoplane

Only by constant practice in calm air can the student familiarize 
himself with exactly the amount of warping and rudder control to 
employ to property offset the lowering of the inner wing in rounding 
a turn. If this be not corrected, the whole machine tends to bank 
excessively and will be apt to slide downward in a diagonal 
direction, Fig. 44. This is a perilous position for the aviator and must 
be guarded against by the manipulation of the warping control so 
as to increase the lift of the inner wing of a biplane, at the same time, 
employing the rudder to counteract this tendency. The use of the 
rudder is of even greater importance on the monoplane, as, in this 
case, warping the inner wing tends to direct the whole machine 
downward instead of raising the inner wing itself. Several bad 
accidents have resulted from monoplanes refusing to respond to the 
warping of the inner wing when making a turn. In such machines, 
the rudder must be practically always employed in connection with 
the warping of the wings in order to keep the machine on an even 
keel, although the controls may not actually be interconnected, 
this being one of the grounds on which foreign manufacturers are 
trying to make use of the Wright principle, without infringing the 
Wright patents, as while they employ warping in connection with 
the simultaneous use of the rudder, the controls are not attached to 
the same lever as in the Wright machine. 

.. figure:: images/Image56.jpg
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   :alt: Fig. 44. An Aeroplane "Banking" as it Rounds a Pylon
   
   Fig. 44. An Aeroplane "Banking" as it Rounds a Pylon

Lateral resistance must also be taken into consideration in 
turning, otherwise the machine, if kept on an even keel, will tend 
to skid through the air and turn about its center of gravity as a pivot. 
In the case of an automobile, the resistance to lateral displacement 
is great, though on a greasy surface it may be small, as when the 
machine skids sideways, a suitable banking of the road being 
necessary to prevent this on turns. Many hold that the banking of the 
aeroplane on turns is only the direct effect of the turning itself, but 
the fallacy of this will be apparent upon a consideration of the law 
of centrifugal force. It is obvious that to make a turn, some force 
must be imparted to the machine to counteract the effect of the 
centrifugal force upon the machine as a whole. And as the sidewise 
projection of the machine is small, a compensating force must be 
introduced. This can be done only by previously banking up the 
machine on the outer wing, so that the pressure of the air under the 
main plane can counteract the tendency to lateral displacement. 
The force then acting under the planes is in a diagonal direction, 
and the angle at which it is inclined vertically depends upon the 
banking of the planes, it being normal to their greater dimension. 
This force can be resolved into two forces, one perpendicular and one 
horizontal, the magnitude of each being dependent upon the degree 
of banking. When the speed of the machine is higher, the amount 
of banking must be greater in order to increase the value of the 
horizontal component in proportion to the increase of the value of the 
centrifugal force at the higher speed, in spite of the fact that the 
forces acting under the planes are also greater due to the higher 
speed. 

As the curve commences, the rudder being put over, the difference 
of the pressures on the two wings, owing to their different flying 
speeds comes into account, as already explained, and care must be 
taken that the banking does not increase abnormally. When the 
turn is completed, the rudder is straightened and the machine is 
again brought to an even keel with the aid of the wing-warping 
control, or the ailerons. The effect of a reverse warping to prevent 
excessive banking, lowering the inside wing tip incidentally, puts a 
slight drag on that wing and assists in the action of turning, as does 
also the provision of small vertical planes between the elevator planes 
of the original Wright machine. Since the adoption of the headless 
type, these surfaces are placed between the forward ends of the skids 
and the braces leading down to them. 

In making a turn, say, to the left, the outside or right-hand 
wing is first raised by lowering the wing tip on that side and the 
rudder is then put over to the left. When the correct amount of 
banking is acquired, the wing tip is restored to its normal position, 
and probably the left wing tip may have to be lowered slightly to 
increase the lift on that side owing to its reduced speed. When the 
turn is completed, the rudder is straightened out and the left wing 
tip lowered to restore the machine to an even keel. Both Glenn 
Curtiss in this country and R. E. Pelterie in France have shown 
that it is possible to maneuver without using the rudder at all, the 
ailerons or wing tips alone being relied upon for this purpose. 

Before flights in other than calm air are attempted, much 
practice is required. The machine must be inspected over and over 
again, and the wind variations studied with a watchful eye. Not 
until this familiarity with machine and atmosphere be acquired 
should flying in a wind be attempted. To the man on the 
ground, wind is simply air moving horizontally, but to the man 
in the air it is quite different. Not only must he consider horizontal 
movement, but vertical draughts and vortices as well. A rising 
current of air lifts a machine, a downward current depresses it, and 
he must learn to take advantage of the former as the birds do. 
Horizontal currents affect forward speed over the ground; swirls and 
vortices create inequalities in wind pressure on the planes and 
disturb lateral balance. Familiarity with all these atmospheric 
conditions can be acquired only after long practice. Against every 
tree, house, hill, fence, and hedge beats an invisible surf of air; 
upward currents on one side and downward on the other. The upward 
draught is not usually dangerous, for it simply lifts the machine; but 
the down draught will cause it to drop. A swift downward glide 
under the full power of the motor must then be made, to increase 
the forward speed and consequently the lift. This explains why 
it is dangerous to fly near the ground in a wind; likewise why the 
beginner should never attempt flying at first in anything but a dead 
calm. 

*Turning in a Wind*. When turning in a wind, two velocities 
must be borne in mind, that of the machine relative to the air and 
that relative to the earth. The former is limited at its lower value 
to that of the flying speed of the machine, and the latter must be 
considered on account of the momentum of the machine as a whole. 
Change of momentum is a matter of horse-power and weight and 
is the governing factor in flying in a wind on a circular course. 
Suppose the flying speed of a machine is a minimum of 30 miles an hour 
relative to the air, and a wind of 20 miles an hour is blowing. The 
actual speed of the machine relative to the earth in flying against 
the wind will be 10 miles an hour. If it be desired to turn down the 
wind, the speed of the machine relative to the earth must be increased
from 10 miles to 50 miles an hour during the turn and a 
corresponding change of momentum must be overcome. There are two ways of 
accomplishing this, either by speeding up the motor to give the 
maximum power, or by rising just previous to making the turn and 
then sweeping down as the turn is made, thus utilizing the 
acceleration due to gravity to assist the motor. The wind's velocity will 
assist the machine also and during the turn it will make considerable 
leeway, a small amount of which is deducted to counteract the 
centrifugal force of the machine. 

Turning in a contrary direction, *i.e.*, up into the wind when 
running with it, requires considerable skill, as when flying 50 miles 
an hour, the tendency on rounding a corner into a 20-mile-an-hour 
wind would be for the machine to rise rapidly in the air. The 
centrifugal force at such a speed is also considerable, causing the machine 
to make much leeway with the wind during the turn. Turning under 
such circumstances should be commenced early, particularly if 
there are any obstructions in the vicinity, and considerable skill 
should be acquired before an attempt is made to fly in such a wind. 

**Starting and Landing**. A machine should always be started 
and landed in the teeth of the wind, and no one but the most 
experienced aviators can afford to disregard this advice, certainly not the 
novice. The precaution is necessary because in landing the machine 
should always travel straight ahead without the possibility of 
lurching and consequently breaking a wing, as frequently happens. 
Contact with the ground is necessarily made at a time when the 
machine is traveling over it at a speed of 30 to 40 miles per hour 
and skidding sideways at 10 to 15 miles per hour, all circumstances 
which tend to wreck an aeroplane. 

**Planning a Flight**. It is easy to lose one's way in the air. For 
that reason it is best to follow the Wright idea of starting out with a 
definite plan, and of landing in some predetermined spot, as aimless 
wandering about may prove disastrous to the inexperienced aviator, 
he may forget which way the wind was blowing, or how much fuel 
he had, or the character of the ground beneath him. Should the 
motor stop, he may make an all too hasty decision in landing. It is 
an easy matter to lose one's bearings in the air, not only because 
the vehicle is completely immersed in the medium in which it is 
traveling, but also because the earth assumes a new aspect from the 
seat of an aeroplane. Cecil Grace was one of those who lost his 
bearings and, as a consequence, his life. Ordinary winds blowing 
over a level country can be negotiated with comparative safety. 
Not so the puffy wind. To cope with that, constant vigilance is 
required, particularly in turning. In a circular flight in a steady 
wind, the only apparent effect is that the earth is swept over faster 
in one direction than in the other. Before a cross-country flight 
is attempted, the starting field should be circled over at a great 
height, as not until then may the long distance flight be started in 
safety. Cross-country flying is, of course, fascinating, and it is a 
sore temptation, at an altitude of a few hundred feet, to throw off 
all caution and fly off over that strange country below, which is, 
indeed, a new land as viewed from aloft. To quote a professional 
aviator: "Here the greatest self-restraint must be exercised. Not 
until the necessary practice has been acquired, not until the right 
kind of confidence has been gained, may one of these trips be 
attempted, and then only after it has been properly planned." 

**Training the Professional Aviator**. Look back over the 
achievements in the air during the comparatively short time that man has 
actually been flying, and it will be noted that the beginners, burning 
up with the enthusiasm of the novice, have performed the most 
spectacular feats and flown with the greatest fearlessness. Curtiss 
was comparatively new at aviation when he won the Gordon-Bennett 
at Rheims in 1909. John B. Moisant, the sixth time he ever went 
up in an aeroplane, flew from Paris to London with a 187-pound 
passenger and 302 pounds of fuel, oil, and spare parts. Hamilton 
made his successful flight from New York to Philadelphia and 
return when he was hardly more than a novice, while Atwood's great 
flights from St. Louis to New York and Boston to Washington were 
made before his name had become known, and Beachey had been 
flying only a few months when he broke the world's altitude record 
at Chicago, while more recent achievements, notably Dixon's flight 
across the Rockies, have emphasized the work of the beginner. All 
of this substantiates the belief held at every aviation headquarters 
in the country—namely, that the older men already in aviation 
may improve the art by executive ability and scientific experiments, 
but most of them will degenerate as flyers. Beyond a certain point, 
frequency of flight does not necessarily create a feeling of confidence 
and safety; rather it brings a fuller appreciation of the dangers, 
and the men who best know how to fly are most content to stay upon 
the ground. 

Professional aviators are drawn from every walk of life, but 
trick bicycle performers, acrobats, parachute jumpers, and racing 
automobile drivers make the most promising applicants. By a kind 
of sixth sense, both the Wrights and Curtiss weed out the promising 
ones after a brief examination. They select men who have an almost 
intuitive sense of balance. Most of these, provided they have nerve, 
have in them the stuff of which aviators are made, even though they 
may have had no experience in any line akin to aviation. Neither 
Curtiss nor the Wrights will accept women under any condition. 
The Moisant school does not share this discrimination and trained 
three women for pilot's licenses during 1911. 

Curtiss and the Wrights are keen in their realization that 
recklessness is pulling a wing feather from aviation every time a 
man is killed, and they are doing their utmost to promote conservatism. 
Curtiss said in an interview: 

   I do not encourage and never have encouraged fancy flying. I regard 
   the spectacular gyrations of several aviators I know as foolhardy and 
   unnecessary. I do not believe that fancy or trick flying demonstrates anything except 
   an unlimited amount of a certain kind of nerve and perhaps the possibilities 
   of what is valueless—aerial acrobatics. Some aviators develop the sense of 
   balance very rapidly, while others acquire it only after long practice. It may 
   be developed to a large extent by going up as a passenger with an experienced 
   man. Therefore, in teaching a beginner, I make it a point to have him make 
   as many trips as possible with someone else operating the machine. In this 
   way the pupil gains confidence, becomes accustomed to the sensation of flying, 
   and is soon ready for a flight on his own hook. This is the method used in 
   training army and navy officers to fly. I have never seen novices more cautious 
   and yet more eager to fly than these young officers. They have always learned 
   every detail of their machines before going aloft, and largely because of this 
   they have developed into great flyers. Perhaps it is due to the military bent 
   of their minds; at any rate, they have made good almost without exception. 

ACCIDENTS AND THEIR LESSONS
###########################

**Press Reports**. Whenever an industry, profession, or what 
not, is prominently before the public, every event connected with 
it is regarded as "good copy" by the daily press. Happenings of so 
insignificant a nature that in any commonplace calling would not 
be considered worthy of mention at all, are "played up." This is
particularly the case with fatalities, and the eagerness to cater to the 
morbid streak in human nature has been responsible for the unusual 
amount of attention devoted to any or all accidents to flying machines, 
and more especially where they have a fatal ending. In fact, this 
has led to the chronicling of many deaths in the field of aviation 
that have not happened—some of them where there was not even 
an accident of any kind. For instance, in many of the casualty lists 
published abroad from time to time, such flyers as Hamilton, 
Brookins, and others have figured among those who have been killed, ever 
since the date of mishaps that they had months ago. 

It will be recalled that five years ago, when the automobile 
began to assume a very prominent position, every fatality for which 
it was responsible was heralded broadcast where deaths caused by 
other vehicles would not be accorded more than local notice. To a 
large extent, this is still true and will probably continue to be the 
case until the automobile assumes a role in our daily existence as 
commonplace as the horse-drawn wagon and trolley car. There is 
undoubtedly ample justification for this and particularly for the 
editorial comment always accompanying it, where the number of 
lives sacrificed to what can be regarded only as criminal recklessness 
is concerned. Still, the fact that in a city like New York the truck 
and the trolley car are responsible for an annual death roll more 
than twice as large as that caused by the automobile, does not call 
for any particular mention. Horses and wagons, we have always 
had with us, and the trolley car long since became too commonplace 
an institution around which to build a sensation. 

As the most novel and recent of man's accomplishments, the 
conquest of the air and everything pertaining to it is a subject on 
which the public is exceedingly keen for news and nothing appears 
to be of too trivial import to merit space. Where an aviator of any 
prominence is injured, or succumbs to an accident, the event is 
accorded an amount of attention little short of that given the death 
of some one prominent in official life. During the four years that 
aviation has been to the fore, about 104 men and one woman have 
been killed, not including the deaths of three or four spectators 
resulting from accidents to aeroplanes, during this period—*i.e.*, from 
the beginning of 1908 to the end of 1911. In view of the lack of 
corroboration in some cases, the figures are made thus indefinite. 
Naturally most of these deaths have occurred in 1910 and 
1911—in fact, 50 per cent took place from 1908 to the end of 1910, and the 
remainder during 1911, since these years were responsible for a far 
greater development, and particularly for a greater increase in the 
number engaged, than ever before. More was accomplished in these 
two years than in the entire period intervening between that day 
in December, 1903, when the Wright Brothers first succeeded in 
leaving the ground in a power-driven machine, and the beginning 
of 1910. 

**Fatal Accidents**. Conceding that the maximum number 
mentioned, 105, were killed during the four years in question, throughout 
the world, it will doubtless come as a surprise to many to learn 
that this is probably not quite twice the number who have 
succumbed to football accidents during the same time in the United 
States alone. Authentic statistics place the number thus killed at 
13 during 1908, 23 in 1909, 14 during 1910, and 17 in 1911, or a total 
of 67. But we have been playing football for a couple of centuries 
or more and this is regarded as a matter of course. The death of a 
football player occurring in some small, out-of-the-way place would 
not receive more than local attention, unless there were other reasons 
for giving it prominence, so that, in all probability, the statistics in 
question fall far short of the truth, rather than otherwise. 

The object of mentioning this phase of the matter is to place 
the question of accidents in its true light. That the development 
of any new art is bound to be attended by numerous mishaps, many 
of them fatal, goes without saying and it is something that can not 
be ignored. Nothing could be worse than attempting to gloss over 
or belittle the loss of life for which aviation has been responsible 
and doubtless will continue to be. Progress invariably takes its 
toll and it is more often founded upon failure than unvarying success, 
for every accident is a failure, in a sense, and every accident carries 
with it its own lesson. 

Where the cause is apparent, it gives an indication of the remedy 
which will bring about the prevention of its recurrence. In other 
words, it serves to point out weaknesses and shows what is necessary 
to overcome them. For that reason alone is the question of accidents 
taken up here, as a study of those that have occurred points the way 
to improvement. Table III gives a resume of the more 
important fatalities that have resulted from the use of a heavier-than-air 
machine during the *past four years*: 

.. figure:: images/Image57.jpg
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   :alt: TABLE III Fatal Aeroplane Accidents
   
Fatalities greatly increased in number during 1911, but not out 
of proportion to the greatly augmented number of aviators. With 
comparatively few exceptions, however, the accidents were more or 
less similar in their nature to those already tabulated, so that it 
would be of no particular value to extend the comparison in this 
manner to cover them. Many of the fatalities during that year were 
not of the aviators themselves, but of the spectators, a fact which calls 
attention to a danger that has not been fully appreciated before. 
At the start of the Paris-Madrid race, the French minister of war 
and another official were killed by a monoplane plunging into the 
crowd, and on the same day, May 21, 1911, five people were killed 
at Odessa, Russia, in the same manner. An unusual type of mishap, 
not mentioned in the tabulation and in which three or four aviators 
lost their lives during 1911, was the burning of the aeroplane in 
midair, or the explosion of the gasoline, setting fire to the wings 
and either burning the aviator at his post or killing him by the fall. 
One such accident occurred in France in September, another in 
Spain two days later, and a third in Germany, in which two men 
were killed. Accidents of an even more unusual nature were the 
collision of two biplanes in midair at St. Petersburg, the collision of 
a motorcycle with a biplane as it swooped down on a race track, and 
the partial wrecking of Fowler's biplane by a bull upon landing 
near Fort Worth, Texas, but these, of course, had no bearing on the 
design of the machines. 

Apart from those specially referred to, the great majority of 
accidents during 1911 may be ascribed to two or three of the causes 
detailed in connection with the comparative table. Of these, lack of 
experience and foolhardiness stand out prominently, the latter 
undoubtedly causing the double fatality at Chicago when two 
aeroplanes plunged into Lake Michigan, drowning one of the aviators, 
while a third machine collapsed in mid-air, hurling the aviator to 
his death on the field. Careful reading of the reports of a large 
number of these accidents usually brings to light the statement "in 
attempting to make a quick turn," or similar phrase, showing that 
the moving cause of the accident was due to subjecting the parts of
the machine to excessive stresses, as outlined in the following pages. 

**Causes**. *Lack of Experience*. It will be at once noticeable 
by Table III that out of a total of 28, no less than 16, or considerably 
more than half of the accidents, were due in one way or another to 
lack of experience. In other words, the aviators had not fully 
complied with the cardinal principle for success in flying upon which 
the Wright Brothers have always laid so much stress, *i.e.*, you must 
first learn to fly before you can attempt to go aloft safely. Nothing 
short of a thorough mastery of the machine can suffice to give the 
aviator the ability to do the right thing at the right moment, in the 
great majority of cases. There will always be occasions when even 
the most skilled aviator will make errors of judgment and frequently 
they cost him his life. But this is equally true of every dangerous 
calling, whether it be running an automobile, driving a locomotive, 
or doing any of the thousand and one things where the responsibility 
for his own and other lives is placed in one man's hands and depends 
to a large extent on his discretion and judgment in cases of emergency, 
so that there will be fatalities from this cause as long as man 
continues to fly. This involves the personal equation that must always 
be reckoned with. Just how many of the accidents that have resulted 
in the fatalities set forth, have been due to the fallibility of the operator 
and for how much the design of the current types of machines is 
responsible, would be hard to say. Fig. 45, for example, which 
shows H. V. Roe in the act of striking the ground in his triplane, illustrates 
an accident due to bad design. Methods of control will be improved 
and simplified and made as nearly "fool-proof" as human ingenuity 
can accomplish, but experience in other fields has demonstrated 
unmistakably that they can never be developed to a point where it 
is impossible to do the wrong thing. With skill at such a premium 
in callings of responsibility which involve only conditions that have 
been familiar for years, how much more so must it be in the air 
about which so little is known? Consequently, the real danger is to 
be found in the personal equation, just as it is in every other mode 
of conveyance, despite the fact that it has been perfected to a point 
which apparently admits of little further development where 
safe-guarding it is concerned. 

.. figure:: images/Image58.jpg
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   :alt: Fig. 45. Roe's Multiplane as it Struck the Ground. An Accident Due to Poor Design

   Fig. 45. Roe's Multiplane as it Struck the Ground. An Accident Due to Poor Design
   
.. figure:: images/Image59.jpg
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   :alt: Fig. 46. DeLessep's Machine after Striking an Obstruction

   Fig. 46. DeLessep's Machine after Striking an Obstruction
   
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   :alt: Fig. 47. Overturned Monoplane Due to a Start in a Gale

   Fig. 47. Overturned Monoplane Due to a Start in a Gale
   
**Obstructions**. Obstructions are bound to play a prominent 
part in accidents to any method of conveyance, but less so in aviation 
than in any other, as it is only in rising and alighting that this danger
is present. Of the two fatal accidents ascribed to this cause, one 
resulted from colliding with an obstruction while running along the 
ground preparatory to rising, and the other from striking an 
obstruction in flight, Fig. 46. In view of the numerous cross-country flights 
that have been made, trips across cities and the like, it is to be 
marveled at that up to the present writing no fatalities have been caused 
by what the aviator most dreads when leaving the safety of the open 
field, that is, being compelled to make a landing through stoppage 
of the motor, whether from a defection or lack of fuel. While no 
fatalities have as yet to be put down to this ever-present danger 
in extended flights, an accident that might have had a fatal 
termination, occurred to Le Blanc during the competition for the 
Gordon-Bennett trophy, which was the chief event of the International Meet 
in October, 1010, at Belmont Park, near New York. Le Blanc and 
his fellow compatriots who were eligible were all experienced 
cross-country flyers, the former having won the *Circuit de L'Est*, a race 
around France, and by far the most ambitious of its kind which had 
been attempted up to that time. They accordingly protested most 
vigorously against flying over the American course to compete for 
the cup which Curtiss had captured at Rheims the year before, 
owing to the fact that it presented numerous dangerous obstructions 
in the form of trees and telegraph poles. But as it was impossible 
to provide any other convenient five-kilometer circuit (3.11 miles) 
as called for by the conditions, the protest was of no avail. After 
having covered 19 of the 20 laps necessary to complete the distance 
of 100 kilometers in time that had never been approached before, 
Le Blanc was compelled to descend through lack of fuel, and as he had 
not risen more than 80 to 100 feet at any time during the race, this 
meant coming down the moment the motor stopped. The result was a 
collision with a telegraph pole, breaking it off and wrecking the 
monoplane, the aviator fortunately escaping any serious injury. During 
the same meet Moisant demolished his Bleriot monoplane by trying 
to start in the face of a high wind, Figs. 47 and 48. 

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   :alt: Fig. 48. View of Moisant Monoplane after a Bad Spill

   Fig. 48. View of Moisant Monoplane after a Bad Spill

**Stopping of Motor**. The mere fact that the motor stops does 
not necessarily mean a disastrous ending to a flight, as is very 
commonly believed, this having been strikingly illustrated by Brookins' 
glide to earth from an altitude of 5,000 feet with the motor dead, 
and Moisant's glide from an even greater height in France. But it 
does mean a wreck unless a suitable landing place can be reached 
with the limited ability to control the machine that the aviator has 
when he can no longer command its power. Motors will undoubtedly 
become more and more reliable as development progresses, but the 
human equation—the partly-filled fuel tank, the loose adjustment 
that is overlooked before starting, and a hundred and one things of 
a similar nature—will always play their role, so that compulsory 
landing in unsuitable places will always constitute a source of danger 
as flights become more and more extended. 

**Breakage of Parts of Aeroplanes**. In studying the foregoing 
table, it can only be a source of satisfaction to the intelligent student 
and believer in aerial navigation, to note how large a proportion 
of the accidents is due to the breakage of parts of the machine. 
This implies a fault in construction, but not in principle. It reveals 
the fact that, in the attempt to secure lightness, strength has 
sometimes been sacrificed, chiefly through lack of appreciation of the 
stresses to which the machine is subjected in operation. At a time 
when weight is regarded almost as the paramount factor by so many 
builders, it is inevitable that some should err by shaving things too 
fine. Lightness is an absolute necessity and failure to achieve it in 
every instance without eliminating the factor of safety has been due 
more to the crude methods of construction and lack of suitable 
materials, than any other cause—conditions that are bound to obtain in the 
early days of any art. Construction is improving rapidly, but 
progress is bound to be attended with accidents of this nature. The 
fact that their proportion is greatly diminishing despite the rapidly 
increasing number of aviators is the best evidence of what is being 
accomplished. When machines are built with such a high factor 
of safety in every part that breakage is an almost unheard-of thing, 
failures from this cause will have been reduced to an unsurpassable 
minimum. 

**Failure of the Control Mechanism**. Under the general classification B, 
are included not alone those accidents directly due to breakage 
of some vital part, but also those instances in which some element 
of the control, such as the elevator, has become inoperative through 
jamming. When an accident happens in the air, it takes place so 
quickly and the machine is so totally wrecked by falling to the ground, 
that it is usually difficult to determine the exact nature of the cause 
through a subsequent examination of the parts, so that it can seldom 
be stated with certainty just what the initial defection consisted of, 
though it may be regarded as a foregone conclusion that, in the case 
of experienced aviators who have previously demonstrated their 
ability to cope with all ordinary emergencies, nothing short of the 
failure of some vital part could have caused their fall. 

This was the case with Johnstone's accident at Denver—an 
occurrence illustrating another phase of the personal equation that 
must be taken into consideration when noting the lessons to be 
learned from a study of accidents and their causes. It is simply 
the old, old story of familiarity breeding contempt—the miner 
thawing out sticks of dynamite before an open fire. Due to the 
rarefied air of Denver, which is at an elevation of more than 5,000 
feet, Johnstone had underestimated the braking powers of the air 
on the machine in landing the day previous and had crashed into a 
fence, breaking one of the right outermost struts between the 
supporting planes. 

Proper regard for safety should naturally have called for its 
replacement by an entirely new strut, but conditions at flying meets 
as at present conducted make quick repairs to damaged machines 
imperative. The damaged upright was accordingly glued and braced 
by placing iron rings around it, the rings themselves being held in 
place by ordinary nails passing through holes in the iron large enough 
to let the nail head slip through. The vibration of the motor and 
the straining of the strut in warping the wings caused the nails to 
work out of the holes, permitting the rings to slide out of place as 
well. Johnstone was an accomplished aviator, much given to the 
execution of aerial maneuvers only possible to the skilled flyer of 
quick and ready judgment. But such performances impose excessive 
stresses on the supporting planes and their braces, and one of 
Johnstone's quick turns caused the repaired struts to collapse through 
the strain of sharply warping the wing tips on that side. He 
immediately attempted to restore the balance of the machine by bringing 
the left wing down with the control, then tried to force the twisting 
on the right side, succeeding momentarily, and a few seconds later 
losing all control and crashing to the ground. It appeared to 
demonstrate that even when disabled an aeroplane is not entirely without 
support, but has more or less buoyancy—something which is really 
more of an optical illusion than anything else due to underestimating 
the speed at which a body falls from any great height. Johnstone's 
accident was the first of its kind, in that he fell from a height of about 
800 feet, during the first 500 of which he struggled to regain control 
of the machine, finally dropping the remaining 300 feet apparently 
as so much dead weight. It showed in a most striking manner the 
vital importance of the struts connecting the supporting surfaces of 
the biplane, any damage to them resulting in the crippling of the 
balancing devices and the end of all aerial support. 

**Biplane vs. Monoplane**. It requires only a glance at Table III 
to show that the greater number of accidents have happened to 
the biplane, yet the latter is generally regarded as the safer of the 
two. Prior to Delagrange's fatal fall in January, 1910, there had 
been only four fatalities with modern flying machines: Selfridge 
and Lefebre were killed in Wright machines, the latter of French 
manufacture, Ferber lost control of his Voisin biplane, and 
Fernandez was killed flying a biplane of his own design. In one case at 
least, that of Lieutenant Selfridge, the accident appears to have 
been due to the failure of a vital part—the propeller. It has since 
become customary to cover the tips of propellers for at least a foot 
or so with fabric tightly fitted and varnished so as to become 
practically an integral part of the wood. This prevents splintering as 
well as avoiding the danger of the laminations succumbing to 
centrifugal force and flying apart. At the extremely high speeds, 
particularly at which direct-driven propellers are run, the stress imposed 
on the outer portion of the blades by this force is tremendous. In 
making any attempt to compare the number of accidents to the 
biplane and the monoplane, it must also be borne in mind that the 
former has been in the majority. 

Delagrange's accident offers two special features of technical 
interest. It was the first fatality to happen with the monoplane 
and was likewise the first fatal accident which appeared to be 
distinctly due to a failure of the main structure of the machine. For 
obvious reasons, it is usually difficult to definitely fix the cause of 
an accident, but in this case there seemed good reason to suppose 
that the main framing of one of the wings gave way altogether. 
Curiously enough, Santos-Dumont had an accident the day following 
from an exactly similar cause, the machine plunging to the ground. 
But with the good fortune that has attended the experimenter 
throughout his long aerial career, he was uninjured. It was definitely 
established that the cause was the fracture of one of the wires taking 
the upward thrust of the wing. In the case of the biplane, the top 
and bottom members are both of wood, with wooden struts, the 
whole being braced with numerous ties of wire. In the monoplane, 
however, the main spars are trussed to a strut below by a 
comparatively small number of wires. The structure of each wing is, in fact, 
very much like the rigging of a sailboat, the main spars taking the 
place of the mast while the wire stays take that of the shrouds, with 
this very important difference, that the mast of the boat is provided 
with a forestay to take the longitudinal pressure when going head 
to the wind, while the wing of an aeroplane often has no such 
provision, the longitudinal pressure due to air resistance being taken 
entirely by the spar. 

It is quite possible that this had something to do with 
Delagrange's accident, as, in the effort to make a new record, his Bleriot 
had just been fitted with a very much more powerful motor. In fact, 
double that for which the machine was originally designed, and this 
was given by the maker as the probable cause of the mishap. As the 
new motor was of a very light type, the extra weight, if any, was 
quite a negligible proportion of the total weight of the machine. 
The vertical stresses on the wings and their supporting wires would, 
therefore, not be materially increased. But as the more powerful 
engine drove the wings through the air a great deal faster, the stresses 
brought upon them by the increased resistance would be 
substantially augmented and, unless provision were made for this, the factor 
of safety would be much reduced. Whether the failure of the wing 
was actually from longitudinal stress or the breaking of a 
supporting wire, as in Santos-Dumont's case, will never be known, but it is 
quite clear that the question of ample strength to resist longitudinal 
stresses should be carefully considered, especially when increasing 
the power of an existing machine. 

The question of the most suitable materials and fastenings 
for the supporting wires is, moreover, a matter which requires very 
careful consideration. In the case of the biplane, the wires are so 
numerous that the failure of one, or even more, may not endanger 
the whole structure, but those of the monoplane are so few that the 
breaking of but one may mean the loss of the wing. In this respect, 
as in others, the conditions are parallel to the mast of the sailboat. 
It is only reasonable to expect, therefore, that similar materials 
would be best adapted to the purpose. At present, however, the 
stays of aeroplane wings are almost invariably solid steel wire, or 
ribbon, while marine shrouds are always of stranded wire rope, solid 
wire not having been found satisfactory. Weight for weight, the 
solid wire will stand a greater strain when tried in a testing machine 
than will the stranded rope, but practice has always demonstrated 
that it is not so reliable. The stranded rope never breaks without 
warning, and sometimes several of its wires may go before the whole 
gives way. As the breakage of the strands can be easily seen, it is 
possible to replace a damaged stay before it becomes unsafe. In the 
case of a single wire, there is nothing to show whether it has 
deteriorated or not. It seems a doubtful policy to use in an aeroplane 
what experience has shown not to be good enough for a boat, and 
stranded wire cables particularly designed for aeronautic use are 
now being placed on the market in this country. 

**Record Breaking**. Striving after records has undoubtedly 
proved one of the most prolific causes of accident. What is wanted 
to make the aeroplane of the greatest practical use is that it should 
be safe and reliable. The tendency of record-breaking machines is 
the exact opposite of this, as the weights of all the most essential 
parts must be cut down to the finest limits possible in order to 
provide sufficient power and fuel-carrying capacity for the record 
flight. It is, in fact, generally the case in engineering that the design 
and materials which will give the best results for a short time are 
essentially different from those which are the most reliable, and 
striving after speed records consists simply in disregarding safety 
and reliability to the greatest extent to which the pilots are willing 
to risk their necks, and there is no difficulty in getting men to take 
practically any risk for the substantial rewards offered. 

The performance of specially sensational feats in the air is 
likewise a fertile source of accidents. One noted aviator who has the 
reputation of being a most conservative and expert operator, while 
endeavoring to land within a set space, made too sudden a turn, which 
resulted in the tail of the machine giving way, precipitating him to 
the ground. In fact, the number of failures resulting from abrupt 
turns shows conclusively that there is too small a factor of safety in 
the construction, not because the added weight could not be carried, 
but because the extreme lightness alone made possible the stunts 
for which there is always applause or financial reward. It may seem 
strange to the man whose only interest in aeronautics is that of an 
observer, that so many should be willing to take such unheard-of 
chances; that an aeronaut will rise to great heights, knowing in 
advance that a vital part of his machine has been deranged, or is 
only temporarily repaired; and that many others will attempt 
ambitious flights with engines or other parts that have never been tested 
previously in operation in the air. Many young and inexperienced 
aviators are not content to thoroughly test out each new part on the 
ground, or close to it, but must go aloft at once to do their 
experimenting, with the usual result of such foolhardiness. If in other 
sports safe conditions were absolutely disregarded in this 
manner—take football as an instance—the resulting fatalities would not be 
charged against the sport itself. But aviation is so extremely 
novel and likewise so mysterious to the uninitiated that this is never 
taken into consideration. 

**Excessive Lightness of Machines**. If, even at the present early 
stage of aviation, machines are being made excessively light for 
purposes of competition, it is time that the contest committees of 
organizations in charge of meetings formulate rules as to the size of 
engines, weight of machines, and similar factors, so that accidents 
will not only be reduced to a minimum, but competition along proper 
lines will develop types of machines which are useful and not merely 
racing freaks, as has already been done in the automobile field. 
Hair-raising performances also should be prohibited, at least until 
such time as improvements in the construction of machines make 
it reasonably certain that they are able, to withstand the terrific 
strains imposed upon them in this manner. Suddenly attempting 
to bring the machine to a horizontal plane after a long dip at an 
appalling angle is an extremely dangerous maneuver, whether it be 
taken in the upper air or is one of the now familiar long glides to 
earth, which require pulling up short when within a few feet of the 
ground and after the dropping machine has acquired considerable 
inertia. The aviator is simply staking his life against the ability of 
the struts and stays to withstand the terrific stresses imposed upon 
them every time this is done. [#]_ 

As at present constructed, many of the machines are not 
sufficiently strong to withstand the utmost in the way of speed and 
sudden turns which the skilled operator is likely to put on them. 
They should be made heavier, or of materials providing greatly 
increased strength with the same weight. That they can be made 
heavier without seriously damaging their flying ability has been 
clearly demonstrated by the numerous flights with one and two 
passengers, and on one occasion in which three passengers besides 
the driver were taken up on an ordinary machine. This was likewise 
tempting fate by overloading, but it served to show the possibilities.

.. figure:: images/Image62.jpg
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   :alt: Fig. 49. Monoplane is Liable to Stand on its Head if Landing is Not Properly Made

   Fig. 49. Monoplane is Liable to Stand on its Head if Landing is Not Properly Made
 
**Landings**. Then there is a class of accidents for which neither 
the aviator nor the machine is responsible, as where spectators have 
crowded on the field, causing the flyers to make altogether too sudden 
or impromptu landings at angles which would otherwise not be 
considered for a moment. This, of course, refers solely to exhibition meets, 
and the comparative immunity of cross-country flights from fatal 
accidents as compared with the latter, speaks for itself in this respect. 
In the open, even the novice seems to be able to pick a safe landing, 
especially if high enough to glide some distance before reaching the 
ground. This brings out the fact that, as a rule, the machines are 
safer in the air—a large part of the danger lies in making a landing. 
Starting places are usually smooth, but landing places may be the 
reverse. When alighting directly against the wind, which is the only 
safe practice, most of the machines will remain on an even keel until 
they come to a stop, but the slightest bump or depression, in 
connection with a side gust of wind, may swerve it around and capsize it, as 
demonstrated by the illustration of a bad landing by De Lesseps, 
Fig. 49. This was emphasized by some of the minor accidents at the 
International Meet near New York. There is no precision or accuracy 
in the movements of a flying machine when rolling slowly over the 
ground after the engine has been shut off, and the aviator is, to a 
certain extent, helpless. The wheels on most machines are placed too 
near the center and too close together. When an attempt is made 
to land with the wind on the quarter or side, although the machine 
may strike the ground safely, owing to the accuracy with which it 
may be controlled in the air while at speed, it is apt to turn after 
rolling a short distance and the wind will then easily capsize it, 
breaking a wing, smashing a propeller, and sometimes injuring the motor 
or the aviator. Accidents from this cause have been common. 

These accidents and collisions with obstructions make plain the 
fact that brakes are quite as necessary on an aeroplane as on any 
other vehicle intended to run on the ground. Practically all 
aeroplanes are fitted with pneumatic tires and ball-bearing wheels and, 
as there is very little head resistance, they will run a considerable 
distance after alighting at a speed of 20 to 30 miles an hour. The 
employment of a brake on the wheels would have averted one of 
the fatal accidents abroad, as noted in Table III. They would 
have enabled Johnstone to stop his machine before colliding with 
the fence surrounding the aviation grounds at Denver, and they 
would have prevented several minor accidents at various meets, 
which, though not endangering the aviator in every instance, have 
often seriously damaged his machine. Every exhibition field is 
obstructed by fences, posts, buildings, and the like, and to avoid 
coming in contact with these, as well as with the irrepressible spectator, 
the aviator should certainly have an effective means of bringing the 
machine to a standstill when it is running along the ground. How 
much more so is this necessary for cross-country flying when the choice 
of a landing place is a difficult matter at best. Ability to come to a 
stop quickly would make it possible to land in restricted places where 
only a very limited run along the ground could be had. 

**Lack of Sufficient Motor Control**. Another class of accidents 
that take place on the ground suggests the necessity for improving 
the motor control. In alighting, the motor is usually stopped by 
cutting off the ignition—ordinarily by grounding or short-circuiting. 
Throttling to stop appears to be seldom resorted to, but as several 
instances have occurred in which the aviator found it impossible to 
cut off the ignition, resulting in a collision with another machine or 
a building, it is evident that the control should be arranged so that 
both methods could be employed. With the increasing use of 
air-cooled motors that may continue to run through self-ignition after 
the spark has been cut off, this is more necessary than ever. 

While it has been demonstrated that the stoppage of the motor 
does not necessarily involve a fall, most aviators will naturally prefer 
to command the assistance of the motor at all times, and in the case 
of motors using a carbureter this should be jacketed either from the 
cooling water or the exhaust, and means provided for increasing the 
air supply to prevent the motor stopping at a great height owing to 
the cold and the rarefied air. The reasons for this have been gone 
into more at length under the heading of "Altitude." With these 
and similar improvements that will be suggested by experience and 
further accidents, there appears to be no reason why aviation can 
not be made as safe as the personal equation will permit it to be. 
There will always be reckless flyers. Ignorance and incompetence 
can not be altogether eliminated any more than they can in sailing, 
hunting, or any other sport. The annual hunting fatalities from 
these causes in this country alone make a total beside which the 
aggregate of four years in aviation the world over, is but an 
insignificant fraction. 

**Parachute Garment as a Safeguard**. To save as many as 
possible of these reckless ones from themselves, so to speak, a parachute 
garment has been devised to ease the shock of the fall. It will be 
recalled that Voisin would not fly in his biplane until he had 
provided himself with a heavily-padded helmet, somewhat on the order 
of the football headpiece. But neither a padded headpiece nor padded 
clothing would avail much against a fall of any kind from an 
aeroplane; hence, the parachute garment. Its object is not to take the 
shock of a fall, as are the pads, nor is it to prevent a fall, but to reduce 
the rate of drop by interposing sufficient air resistance to make the 
fall safe. This new parachute is in the form of a loose flowing 
garment, securely fastened to the body and fitted over a framework 
carried on the aviator's back. The lower ends of the garment are 
secured to the ankles. The arrangement is such that when the aviator 
throws out his arms, the garment is extended somewhat in umbrella 
or parachute form, thus creating sufficient resistance to prevent too 
rapid a descent. Experiments have been made with this parachute 
dress in which the wearer has jumped from buildings, cliffs, and other 
heights, and the garment has assumed its role of parachute at once, 
permitting a safe and easy descent. 

**Study of Stresses in Fancy Flying**. To sum up, it will be seen 
that the most prolific cause of fatalities is the personal equation. 
Of all the many dangers encountered in aeroplaning, one of the most 
clearly defined, as well as one of the most seductive, results from fancy 
flying: from wheeling round sharp, horizontal curves; from conic 
spiraling; from cascading, swooping, and undulating in vertical plane 
curves, popularly dubbed "stunts." These are forms of flying in 
which aviators constantly vie with one another. They frequently 
result in imposing stresses upon the machine which are far beyond 
its capacity to withstand. The danger is particularly alluring to 
reckless young aviators engaged in public exhibitions. The death 
of St. Croix Johnstone, at the Chicago Meet in the summer of 1911, 
affords a typical illustration of what may be expected as the result 
of such performances. Nevertheless, partly because they do not 
adequately appreciate the risk, and largely, no doubt, because of 
the liberal applause accorded by an admiring throng which also fails 
to realize the hazardous nature of the fascinating maneuvers, there 
will doubtless always be aviators to undertake such feats. 

Singularly enough, the exact magnitude of such hazards, or 
more accurately, the extent of the increased stress in the machine, 
though beyond even the approximate guess of the aviator, is capable 
of nice computation in terms of the speed and curvature of flight. 
During an exhibition meet in Washington, D. C, during the summer 
of 1911, Glenn H. Curtiss found difficulty in restraining one of his 
young pupils from executing various hair-raising maneuvers. He 
would plunge from a great elevation to acquire the utmost speed,
then suddenly rebound and shoot far aloft. He would undulate about 
the field, and on turns would bank the machine until the wings 
appeared to stand vertical. Curtiss solemnly warned the young 
aviator and earnestly restrained him, pointing out the dangers of 
sweeping sharp curves at high speed, of swooping at such dangerous 
angles, and the like. Curtiss then turned to A. F. Zahm and expressed 
the wish that someone would determine exactly the amount of the 
added stress in curvilinear flight. The following, published by Zahm, 
in the *Scientific American*, gives the method of calculating this: 

When a body pursues a curvilinear path in space, the centripetal force 
urging it at any instant may be expressed by the equation 

Fn = m(V/R)² (absolute units) = (m/g)(V²/R) (gravitational units) 

in which *Fn* is the centripetal force, *m* the mass of the body, *V* its velocity, 
and *R* the instantaneous radius of curvature of the path followed by its center 
of mass. Since the mass may be regarded as constant for any short period, 
the equation may be expressed by the following simple law: 

*The centripetal force varies directly as the square of the velocity of flight
and inversely as the instantaneous radius of the curvature of its path.*

In applying the above equation to compute the stress in an 
aeroplane of given mass *m*, we may assume a series of values for 
*V* and *R*, compute the corresponding values for *Fn*, and tabulate 
the results for reference. Table IV has been obtained in this manner. 
It may be noted that on substituting in the equation, *V* is taken as 
representing miles per hour, *R* as feet, and *g* as 22 miles an hour, 
in order to simplify the figuring, this being 32.1 feet per second. 
The table shows at a glance the centripetal force acting on an 
aeroplane to be a fractional part of the gravitational force, of weight of the 
machine and its load. For example, if the aviator is rounding a curve 
of 300 feet radius at 60 miles per hour, the centripetal force is 0.55 
of the total weight. At the excessively high speed of 100 miles per 
hour and the extremely short radius of 100 feet, the centripetal force 
would be 4.55 times the weight of the moving mass. The pilot would 
then feel heavier on his seat than he would sitting still with a man 
of his own weight on either shoulder. For speeds below 60 miles 
per hour and radii of curvature above 500 feet, the centripetal force 
is less than one third of the weight. The table gives values for 
speeds of 30 to 100 miles per hour, by increments of 10 miles and for 
radii of curvature of 100 to 500 feet, by increments of 100 feet, so 
that intermediate speeds and radii may readily be calculated. 

.. figure:: images/Image63.jpg
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   :alt: Fig. TABLE IV. Centripetal Force Acting on Aeroplane at Various Speeds and Curvatures of Flight

The entire stress on the aeroplane in horizontal flight, being 
substantially the resultant of the total weight and the centripetal 
force, can readily be figured by compounding them. Thus in 
horizontal wheeling, the resultant force as shown in the diagram, Fig. 
50, is approximately 

*F = √(Fn²+W²)*

In swooping, or undulating in a vertical plane, the resultant 
force at the bottom of the curve has its maximum value 

*F = (Fn+W)*

and at any other part of the vertical path, it has a more complex 
though smaller value, which need not be given in detail. 

It is obvious that the greatest stress on the machine occurs at 
the bottom of a swoop, if the machine be made to rebound on a sharp 
curve. The total force *(Fn+W)* sustained at this point may 
be found from the table, if *V* 
and *R* be known, simply by 
adding 1 to the figures given, 
then multiplying by the 
weight of the machine. For 
example, if the speed be 90 
miles per hour and the radius of 
curvature 200 feet, the total force on the sustaining surface would 
be 2.84 times the total weight of the machine. In this case, the stress 
on all parts of the framing would be 2.84 times its value in level 
flight, when only the weight has to be sustained. The pilot would 
feel nearly three times his usual weight. 

.. figure:: images/Image64.jpg
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   :alt: Fig. 50. Force Diagram in Horizontal Wheeling 

   Fig. 50. Force Diagram in Horizontal Wheeling 

From the foregoing, it is apparent that in ordinary banking 
at moderate speeds on moderate curves, the additional stress due to 
centripetal force is usually well below that due to the weight of the 
machine, and that in violent flying, the added stress may 
considerably exceed that due to the weight of the machine and may 
accordingly be dangerous, unless the aeroplane be constructed with a 
specially high factor of safety. But there is nothing in the results here 
obtained that seems to make sharp curving and swooping prohibitive. 
If the framing of the machine be given an extra factor of safety, at 
the expense perhaps of endurance and speed, it may be made 
practically unbreakable by such maneuvers, and still afford to the pilot 
and spectators alike all the pleasures of fantastic flying. 

**Methods of Making Tests**. In order to obtain actual data for 
the fluctuations of stress in an aeroplane in varied flying, it is 
suggested that the stress or 
strain of some tension or 
compression member of 
the machine be recorded 
when in action; or simpler 
still, perhaps, that a record of the aeroplane's acceleration be taken 
and particularly its transverse acceleration. A very simple device to 
reveal the transverse acceleration of an aeroplane in flight would be 
a massive index elastically supported. A lath or flat bar stretching 
lengthwise of the machine, one end fixed, the other free to vibrate, 
and carrying a pencil along a vertical chronograph drum, would 
serve the purpose. This could be protected from the wind by a 
housing as shown in the sketch, Fig. 51. 

.. figure:: images/Image65.jpg
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   :alt: Fig. 51. Method of Boxing an Acceleration Recorder

   Fig. 51. Method of Boxing an Acceleration Recorder

An adjustable sliding weight could be set to increase or diminish 
the amplitude of the tracing, and an aerial or liquid damper could be 
added to smooth the tracing. The zero line would be midway between 
the tracings made on the drum by the stationary instrument when 
resting alternately in its normal position and upside down; the distance 
between this zero line to the actual tracing of the stationary 
instrument would be proportional to the aeroplane stresses in level, 
rectilinear flight; while in level flight on a curve, either horizontal or 
vertical, the deviation of the mean tracing from the zero line would 
indicate the actual stress during such accelerated flight. Of course, 
the drum could be omitted and a simple scale put in its place, so 
that the pilot could observe the mean excursion of the pencil or pointer 
from instant to instant; also, the damper of such excursion could 
be adjusted to any amount in the proposed instrument if the 
vibrating lath fitted its encasing box closely with an adjustable passage 
for the air as it moved to and fro; or if light damping wings were 
added to the lath, or flat pencil bar. 

Another method would be to obtain by instantaneous 
photography the position of the centroid of the aeroplane at a number of 
successive instants, from which could be determined its speed and 
path, or *V* and *R* of the first equation, by which data, therefore, 
the stress could be read from Table IV. 

Perhaps the simplest plan would be to add an acceleration 
penholder, with its spring and damper, to any recording drum the 
aeroplane may carry for recording air pressure, temperature, speed, and 
so forth. Indeed, all such records could be taken on a single drum. 

A score of devices, more or less simple, but suitable for 
revealing the varying stress in an aeroplane, will occur to any engineer 
who may give the subject attention. And it is desirable in the 
interests both of aeroplane design and of prudent manipulation that 
someone obtain roughly accurate data for the stresses developed in 
actual flight. 

**Increment of Speed in Driving**. It is commonly supposed by 
aviators that the *increment* of speed due to driving is very prodigious. 
An easy formula will determine the major limit of such speed 
increment. If the initial and natural speed of the aeroplane be *v*, and 
the change of level in diving be *h*, while the speed at the end of the 
dive be *V*, the minimum change of level necessary to acquire any 
increment of speed, *V—v*, may be found from the equation 

h = (V - v)/2g

.. figure:: images/Image66.jpg
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   :alt: TABLE V Minimum Change of Level Necessary to Produce Various Speed Increments

If, as before, *g* be taken as 22 miles per hour, the equation reduces 
to the convenient formula 

h = (V-v)/30

in which *V* and *v* are taken in miles per hour. Assuming various 
values for *V* and *v*, Table V has been found for the corresponding 
values of *h* in feet: For example, if the natural speed of the 
aeroplane in level flight be 50 miles per hour, and the aviator wishes to 
increase the speed by 20 miles per hour, he must dive at least 80 
feet, assuming that the aeroplane falls freely, like a body in vacuo, or 
that its propeller overcomes the air resistance completely; 
otherwise the fall must be rather more than 80 feet. 

It has been suggested that a contest be arranged to determine 
which aviator could dive most swiftly and rebound most suddenly, 
the prize going to the one who should stress his machine most as 
indicated by the accelerograph above proposed. But to avoid 
danger, the contest would have to be supervised by competent 
experimentalists, and would be best conducted over water. It is safe to say 
that more than one well-known aeroplane would be denied entry in 
such a contest because of lack of a sufficient factor of safety in its 
construction. 

**Dirigible Accidents**. Because its wrecks are spectacular and 
the loss involved tremendous, the dirigible has probably earned an 
undeserved reputation, though it must be admitted that the big 
airships have come to grief with surprising regularity. The fact 
must be noted, however, that when an airplane is wrecked, the 
aviator seldom escapes with his life, while the spectators' lives are 
endangered to an even greater extent, whereas in the case of the 
dirigible, the loss is simply financial, both the crew and passengers 
usually escaping without a scratch. This is largely due to the fact 
that the majority of accidents to dirigibles have happened on the 
ground, and have been caused by lack of facilities for properly 
handling or "docking" the huge gas bag. Of course, lack of flotation 
or an accident to the motors, or both combined, have brought two 
of the numerous Zeppelins to earth in a very hazardous manner, 
though no one was killed, while four French army officers lost their 
lives in the Republique disaster, the exact cause of which was never 
definitely ascertained. This was likewise the case with Erbsloeh 
and his companion who were dropped from the sky, their airship 
having taken fire. It was thought that ignition was caused by 
atmospheric electricity, in this instance. 

By far the great majority of later dirigible accidents have been 
due solely to the crude methods of handling the airships on the 
ground, and the frequency with which these have occurred should 
certainly have been responsible for the adoption of improvements 
in this respect at an earlier day. 

For instance, the Morning Post, a big Lebaudy type bought 
for English use, had the envelope ripped open by an iron girder 
projecting from its shed. Repairs took several months, and at the end 
of the first trial thereafter, the ship was again Wrecked in landing. A 
company of soldiers failed to hold the big craft and it drifted 
broadside into a clump of trees, hopelessly wrecking it. In attempting to 
dock the Deutschland I, 200 men were unable to hold it down, a 
heavy gust of wand catching the big airship and pounding it down 
on top of a wind break that had been specially erected at the entrance 
of the shed for protection. A similar accident happened to the big 
Parseval, a violent gust of wind casting it against the shed and tearing 
such a hole in the envelope that the gas rushed out and the car 
dropped 30 feet to the ground. The big British naval dirigible of the 
rigid type, the Mayfly, was broken in half in attempting to take it 
out of the shed the first time. A cross wind was blowing and the 
gas bag of one of the central sections was torn, deflating it and 
showing in a striking manner that the solidity of a rigid dirigible results 
chiefly from the aerostatic pressure of the gas in its various 
compartments. Without the gas lift, a rigid frame is so in reality only for 
certain limited distances, as was shown by the total collapse of the 
Mayfly's frame after having been subjected to the opposed leverage 
of the parts on either side of the original break. This, of course, 
was an error in design, as the frame of a rigid dirigible should 
certainly not be so weak in itself as to collapse upon the deflation of a 
single one of the central compartments. The incident on the trip of 
the Zeppelin III to Berlin, in 1909, when the flying blades of a broken 
propeller pierced the hull without causing an accident, shows how 
much resistance it may offer. 

.. [#] This is exactly what occured at the Chicago Meet, August 15, 1911, when Badger's Baldwin biplane collapsed at the end of a long dive, causing the death of the aviator. 

AMATEUR AVIATORS
################

It will probably come as a surprise to the average reader to 
learn that at the end of 1910, there were more than a thousand 
amateur aviators in this country, though all the flights which form the 
subject of newspaper reports have been the work of not more than 
a dozen flyers and doubtless half the population has not as yet seen 
an aeroplane in flight. The desire to fly, whether it be to satisfy one's 
desire to soar above the world in seeming defiance of natural laws, 
or merely to obtain the financial reward that is won by successful 
flight, attracts a great many from all stations and walks of life. This 
is particularly true among older boys who look on aviation as an 
advanced form of kite-flying. An example of rather serious work 
along this line may be cited of two high school boys of Chicago, 
Harold Turner and Fred Croll, who built a monoplane weighing 125 
pounds, Fig. 52. This machine, although too small for a motor, 
was equipped with rudder and other operating planes and levers, 
the elevating plane and ailerons being automatically operated by 
an electrical device. On one of its flights the machine, carrying a 
120 pound operator, was started and propelled by attaching it to an 
automobile; it rose to a height of 15 feet, and remained in the air 43 
seconds. 

Contrary to all precedent, the average amateur is bent upon 
achieving what the skilled professional considers as beyond even 
his talent and resources—that of building his own flying machine. 
With every other mechanical vehicle, the amateur learns to drive first 
and the majority are content with that achievement—for example, 
very few chauffeurs have any great ambition to build their own 
automobiles. With flying machines (one of the most difficult of 
mechanical contrivances), nearly all amateurs want to construct 
new types for themselves and all confidently expect to fly with 
no more knowledge than that gained in constructing them. We all 
have to be apprentices before becoming masters, so all aviators 
necessarily have to be learners and "grass cutters" before being professionals. 
Charles K. Hamilton was an exception, but he was already an expert 
pilot of dirigible balloons, and he did not try to build his own 
aeroplane. Willard, Mars, and Ely, all Curtiss pupils, flew after a very 
short training, but they did not attempt to construct aeroplanes for 
themselves. This is also true of Clifford B. Harmon, the champion 
amateur. 

.. figure:: images/Image67.jpg
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   :alt: Fig. 52. What an Amateur Aviator Can Do in Building an Aeroplane

   Fig. 52. What an Amateur Aviator Can Do in Building an Aeroplane

**Classes of Amateurs**. *Inventors*. Generally speaking, 
amateurs are of two classes. Those of the *first class* believe they have 
conceived some entirely new system or invention, or an 
improvement on some machine that has previously proved a failure; they 
think they have discovered the secret which other inventors who 
preceded them failed to grasp. They expend their meager capital 
in trying to realize high hopes. A comparatively small number 
ever get as far as completing the machine and one trial on the field 
is usually sufficient to put a quietus on those who do, as it is 
disappointing, to say the least, to see the result of a number of months' 
work undone in a twinkling without the machine having shown the 
least disposition or ability to get off terra firma. 

*Would Be Performers*. *The second class* finds its chief 
incentive in the munificent reward to be gained with what appears to be 
comparatively little effort or expenditure, and the amateur who is 
seeking financial returns has no alternative except to build his own 
machine, or enter either the Wright or Curtiss school of flying and 
secure a berth with one of these companies. 

**Wright and Curtiss Patents**. This is the result of conditions 
at present obtaining in the field of aviation. The only generally 
successful types of American aeroplanes are the Wright and Curtiss, 
and the acquirement of a biplane of either type means the 
expenditure of at least $5,000 for the machine alone, and they are sold only 
to individuals on the express condition that the machines are not 
to be used for exhibition or as a means of profit to the owner. The 
manufacturers have expert flyers of their own who attend meets 
and fairs throughout the country. It would make their monopoly 
impossible to allow outsiders to fly their aeroplanes publicly or to 
exhibit them. By this restriction the price of the machines is kept 
up and large returns are gained by exhibitions and flying. 

To break this monopoly by importing European machines is 
not possible. All the successful aeroplanes made abroad such as the 
Farman, Cody, and Sommer biplanes; and the Bleriot, Antoinette, 
and Grade monoplanes are fitted with devices of control or stability, 
or both, covered by the Wright patents and can not be flown in this 
country without legal trouble. The numerous foreign aviators 
who brought over their machines in the fall of 1910 to compete at 
the International Meet, did so only on being granted a concession 
by the Wright Company to the effect that they would not be 
considered as infringers and sued. Similar arrangements were made at 
subsequent meets and this handicap will always be present where 
foreign machines are used. 

*Evasion by Invention of New Types*. But when he thinks of 
the unprecedented sums paid professionals for simply exhibiting 
their machines and making short flights, the amateur is anxious to 
obtain a share of the profits. No thought is given the fact that were 
he and all his kind permitted to fly, the achievement would soon 
be commonplace and the aviator's golden age would be over. There
are accordingly hundreds of would-be aviators in this country today 
who are striving to evade the Wright basic patents by either 
devising entirely new types of aeroplanes, or by inventing new methods 
of control and stability that will not infringe. Others, reasoning 
that the old aeroplanes built before the advent of the Wright machine 
cannot be held as infringements owing to priority, propose to develop 
Maxim, Langley, and Ader machines, though the dictum in the 
New York Court of Appeals decision referred to under the head of 
"Legal Status of Wright Patent," which states that a prior machine 
which *had never been known to fly* would not be considered an 
anticipation of a modern successful machine, may prove a stumbling block 
in their case as well. Thus, a round of the workshops of these 
enthusiasts reveals a host of heavier-than-air machines of every 
conceivable type and shape, every one of which, according to its builder, 
is *an aeroplane that will fly*. Mineola and Garden City, Long Island, 
harbor a score of these little shops the year round, but the same 
scenes are being enacted on a smaller scale in almost every state in 
the Union, and particularly in California, Ohio, Kansas, 
Massachusetts, and Arizona, in addition to which there are many who are 
carrying their experiments on in secret. Each believes deep in his 
heart that he will succeed where a master failed. 

"Maxim failed with this type of machine," quotes one. "How 
did he expect to fly when his control was not proportionate to the 
machine's lift capacity?" Seemingly, nobody ever thought of that 
and our friend will make a fortune by going Maxim one better, but 
he does not. After months of labor and a great deal of expense he 
finds that some unforeseen difficulty develops which keeps his 
machine to earth as if it were part and parcel of it. Another has 
conceived a type of monoplane that is entirely new—different from 
any existing type—and as the latter are all foreign, he prides 
himself on having developed a monoplane that will be entirely 
American—the first and only American monoplane. Theoretically, it is a 
wonder; mechanically it is correct; and it speeds over the turf with 
surprising velocity; but when the elevating rudder is operated to 
make the machine rise, it balks and plunges head first into the 
ground. Again and again, the propeller and other broken parts 
are replaced at no small expense; again and again the inventor goes 
over every part of the machinery and computes the dimensions of 
the supporting surface to see if it all corresponds with the formula 
of his special theory. But time after time, the aeroplane acts like a 
jumping frog and lands head first. At last, its builder becomes 
convinced that there is something radically wrong and begins to depart 
from his original plans, involving changes that simply mean a waste 
of effort and money, since the inventor does not himself know what 
he is trying to correct and no one else knows better than he what 
the trouble is. 

*Evasion by Acquiring European Types*. Others still, realizing 
from the foregoing experiences that it is almost impossible to 
construct an entirely new type of aeroplane off-hand, acquire European 
types and propose to fit them with new control and stability devices, 
such as are not covered by the Wright patents. So far, none has 
succeeded. Somehow, the Wrights seem to have covered all the 
conceivable working devices for control and stability, and the 
numerous attempts have accordingly resulted in failure. Undoubtedly, 
some of these aeroplanes built by amateurs may really be capable 
of flight; but how is the inventor to know it when he lacks the ability 
to operate it? To know how to fly an aeroplane is a condition 
precedent to success in the field of aviation that can not be met by 
building of a machine. The beginner is thus badly handicapped. Even 
though his machine may embody the elements essential to successful
flight, he may never be able to establish the fact, since his first 
blundering attempt or two frequently ends by wrecking the machine, 
and many have neither the means nor the stamina to persevere 
further after a few bad wrecks, involving weeks and weeks of rebuilding 
each time. He can not engage an expert to fly his machine for him, 
as the expert's time per minute figures out a price that makes him 
gasp, and even at that the expert professional's time is pretty much 
all taken. Furthermore, very few would run the risk of attempting 
to fly an untried aeroplane—they have more to lose through 
accidental injury than the builder has through the failure of his theories. 

And so it is with most inventors. They may have conceived 
something really good, but it is not complete, and an aeroplane is 
hardly worth its weight as junk unless it is. Hundreds of patents 
are taken out every year on devices to be used on heavier-than-air 
machines; inventors by scores make daily rounds trying to interest 
financiers in some seemingly wonderful mechanical scheme, and 
dozens of companies are organized each year to exploit some 
especially promising inventions. Numbers of aeroplanes are constructed 
and hailed as marvels, but, somehow, when a successful flight is made 
by an amateur it is always with some standard aeroplane, either of 
the Curtiss or Farman types, and mostly the former. In fact, the 
Curtiss has become a favorite with the amateur since the Federal 
court refused to sustain the granting of a preliminary injunction in 
favor of the Wright Company against Glenn H. Curtiss. It is 
accordingly being taken for granted in general that the outcome of the 
Wright vs. Curtiss litigation will be to declare the Curtiss machine 
non-infringing. Should it be the other way about, there will certainly 
be gloom and despair in the amateur camps throughout the country. 
However, neither the Wrights nor Curtiss impose any restriction 
upon the building of machines of their types for experimental 
purposes, so that the amateur who wishes to copy them may safely do 
so, provided no attempt be made to employ the machine for 
purposes of public exhibition or financial gain. 

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    EXAMINATION PAPER 

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    BUILDING AND FLYING AN 

    AEROPLANE 

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    **PART II**

**Read Carefully**: Place your name and full address at the head of the 
paper. Any cheap, light paper like the sample previously sent you may be 
used. Do not crowd your work, but arrange it neatly and legibly. *Do not 
copy the answers from the Instruction Paper; use your own words so that we 
may be sure that you understand the subject*. 

1. Contrast the Bleriot with the Curtiss in every essential particular.

2. Give details of the Bleriot running gear.

3. How is the supporting plane of the Bleriot built and reinforced?
4. What sort of fabric is used to cover the plane and how is it fastened on?

5. Describe by sketch the Bleriot control system.

6. How does the location of the motor in the Bleriot compare with its location in the Curtiss?

7. What is “grass-cutting” and why is it practiced?

8. Describe some of the devices used in aviation schools.

9. How is the elevating plane manipulated to start the aeroplane from the ground?

10. How is the static balance of a machine determined?

11. How does warping the wings affect the behavior of an aeroplane? How should this be practiced?

12. Give the process of making a turn in an aeroplane.

13. What is “banking”? What must be done to prevent excessive banking on a turn?

14. How can a turn be made in a wind?

15. Why should the start and the landing always be made in the teeth of the wind?

16. What is the attitude of the masters of aviation toward fancy flying?

17. Classify the most common sources of accidents.

18. What must an aviator do in case his motor stops in midair? Is this considered a dangerous situation?

19. What are the relative merits of biplane and monoplane as regards the avoidance of accidents?

20. What are some of the devices used to protect the aviator in case his machine collapses?

21. Analyze rather carefully the additional stresses put upon an aeroplane when an aviator suddenly swoops and then rights his machine by a quick movement of the control.

**After completing the work, add and sign the following statement:**

I hereby certify that the above work is entirely my own.

(Signed)

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