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diff --git a/.gitattributes b/.gitattributes new file mode 100644 index 0000000..6833f05 --- /dev/null +++ b/.gitattributes @@ -0,0 +1,3 @@ +* text=auto +*.txt text +*.md text diff --git a/907-h.zip b/907-h.zip Binary files differnew file mode 100644 index 0000000..4d64b23 --- /dev/null +++ b/907-h.zip diff --git a/907-h/907-h.htm b/907-h/907-h.htm new file mode 100644 index 0000000..31342e3 --- /dev/null +++ b/907-h/907-h.htm @@ -0,0 +1,7581 @@ +<?xml version="1.0" encoding="us-ascii"?> + +<!DOCTYPE html + PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd" > + +<html xmlns="http://www.w3.org/1999/xhtml" lang="en"> + <head> + <title> + Flying Machine: Construction and Operation, by W.J. Jackman and Thos. H. + Russell + </title> + <style type="text/css" xml:space="preserve"> + + body { margin:5%; background:#faebd0; text-align:justify} + P { text-indent: 1em; margin-top: .25em; margin-bottom: .25em; } + H1,H2,H3,H4,H5,H6 { text-align: center; margin-left: 15%; margin-right: 15%; } + hr { width: 50%; text-align: center;} + .foot { margin-left: 20%; margin-right: 20%; text-align: justify; text-indent: -3em; font-size: 90%; } + blockquote {font-size: 97%; font-style: italic; margin-left: 10%; margin-right: 10%;} + .mynote {background-color: #DDE; color: #000; padding: .5em; margin-left: 10%; margin-right: 10%; font-family: sans-serif; font-size: 95%;} + .toc { margin-left: 10%; margin-bottom: .75em;} + .toc2 { margin-left: 20%;} + div.fig { display:block; margin:0 auto; text-align:center; } + div.middle { margin-left: 20%; margin-right: 20%; text-align: justify; } + .figleft {float: left; margin-left: 0%; margin-right: 1%;} + .figright {float: right; margin-right: 0%; margin-left: 1%;} + .pagenum {display:inline; font-size: 70%; font-style:normal; + margin: 0; padding: 0; position: absolute; right: 1%; + text-align: right;} + pre { font-style: italic; font-size: 90%; margin-left: 10%;} + +</style> + </head> + <body> +<pre xml:space="preserve"> + +Project Gutenberg's Flying Machines, by W.J. Jackman and Thos. H. Russell + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Flying Machines + Construction and Operation + +Author: W.J. Jackman and Thos. H. Russell + +Release Date: July 26, 2008 [EBook #907] +Last Updated: February 7, 2013 + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK FLYING MACHINES *** + + + + +Produced by Charles Keller, and David Widger + + + + + +</pre> + <p> + <br /><br /> + </p> + <h1> + FLYING MACHINE: CONSTRUCTION AND OPERATION + </h1> + <p> + <br /> + </p> + <h2> + By W.J. Jackman and Thos. H. Russell + </h2> + <p> + <br /> <br /> + </p> + <p> + A Practical Book Which Shows, in Illustrations, Working Plans and Text, + How to Build and Navigate the Modern Airship. + </p> + <p> + W.J. JACKMAN, M.E., Author of "A B C of the Motorcycle," "Facts for + Motorists," etc. etc. + </p> + <p> + and + </p> + <p> + THOS. H. RUSSELL, A.M., M.E., Charter Member of the Aero Club of Illinois, + Author of "History of the Automobile," "Motor Boats: Construction and + Operation," etc. etc. + </p> + <p> + With Introductory Chapter By Octave Chanute, C.E., President Aero Club of + Illinois + </p> + <h3> + 1912 + </h3> + <p> + <a name="link2H_PREF" id="link2H_PREF"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + PREFACE. + </h2> + <p> + This book is written for the guidance of the novice in aviation—the + man who seeks practical information as to the theory, construction and + operation of the modern flying machine. With this object in view the + wording is intentionally plain and non-technical. It contains some + propositions which, so far as satisfying the experts is concerned, might + doubtless be better stated in technical terms, but this would defeat the + main purpose of its preparation. Consequently, while fully aware of its + shortcomings in this respect, the authors have no apologies to make. + </p> + <p> + In the stating of a technical proposition so it may be clearly understood + by people not versed in technical matters it becomes absolutely necessary + to use language much different from that which an expert would employ, and + this has been done in this volume. + </p> + <p> + No man of ordinary intelligence can read this book without obtaining a + clear, comprehensive knowledge of flying machine construction and + operation. He will learn, not only how to build, equip, and manipulate an + aeroplane in actual flight, but will also gain a thorough understanding of + the principle upon which the suspension in the air of an object much + heavier than the air is made possible. + </p> + <p> + This latter feature should make the book of interest even to those who + have no intention of constructing or operating a flying machine. It will + enable them to better understand and appreciate the performances of the + daring men like the Wright brothers, Curtiss, Bleriot, Farman, Paulhan, + Latham, and others, whose bold experiments have made aviation an + actuality. + </p> + <p> + For those who wish to engage in the fascinating pastime of construction + and operation it is intended as a reliable, practical guide. + </p> + <p> + It may be well to explain that the sub-headings in the articles by Mr. + Chanute were inserted by the authors without his knowledge. The purpose of + this was merely to preserve uniformity in the typography of the book. This + explanation is made in justice to Mr. Chanute. + </p> + <p> + THE AUTHORS. <a name="link2H_4_0002" id="link2H_4_0002"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + IN MEMORIAM. + </h2> + <p> + Octave Chanute, "the father of the modern flying machine," died at his + home in Chicago on November 23, 1910, at the age of 72 years. His last + work in the interest of aviation was to furnish the introductory chapter + to the first edition of this volume, and to render valuable assistance in + the handling of the various subjects. He even made the trip from his home + to the office of the publishers one inclement day last spring, to look + over the proofs of the book and, at his suggestion, several important + changes were made. All this was "a labor of love" on Mr. Chanute's part. + He gave of his time and talents freely because he was enthusiastic in the + cause of aviation, and because he knew the authors of this book and + desired to give them material aid in the preparation of the work—a + favor that was most sincerely appreciated. + </p> + <p> + The authors desire to make acknowledgment of many courtesies in the way of + valuable advice, information, etc., extended by Mr. Octave Chanute, C. E., + Mr. E. L. Jones, Editor of Aeronautics, and the publishers of, the New + England Automobile Journal and Fly. + </p> + <p> + <br /> <br /> + </p> + <hr /> + <p> + <br /> <br /> + </p> + <blockquote> + <p class="toc"> + <big><b>CONTENTS</b></big> + </p> + <p> + <br /> + </p> + <p class="toc"> + <a href="#link2H_PREF"> PREFACE. </a> + </p> + <p class="toc"> + <a href="#link2H_4_0002"> IN MEMORIAM. </a> + </p> + <p> + <br /> + </p> + <p class="toc"> + <a href="#link2H_4_0003"> <big><b>FLYING MACHINES: CONSTRUCTION and + OPERATION</b></big> </a> + </p> + <p> + <br /> + </p> + <p class="toc"> + <a href="#link2HCH0001"> CHAPTER I. EVOLUTION OF TWO-SURFACE FLYING + MACHINE. </a> + </p> + <p class="toc"> + <a href="#link2HCH0002"> CHAPTER II. THEORY, DEVELOPMENT, AND USE. </a> + </p> + <p class="toc"> + <a href="#link2HCH0003"> CHAPTER III. MECHANICAL BIRD ACTION </a> + </p> + <p class="toc"> + <a href="#link2HCH0004"> CHAPTER IV. VARIOUS FORMS OF FLYING MACHINES. + </a> + </p> + <p class="toc"> + <a href="#link2HCH0005"> CHAPTER V. CONSTRUCTING A GLIDING MACHINE. </a> + </p> + <p class="toc"> + <a href="#link2HCH0006"> CHAPTER VI. LEARNING TO FLY. </a> + </p> + <p class="toc"> + <a href="#link2HCH0007"> CHAPTER VII. PUTTING ON THE RUDDER. </a> + </p> + <p class="toc"> + <a href="#link2HCH0008"> CHAPTER VIII. THE REAL FLYING MACHINE. </a> + </p> + <p class="toc"> + <a href="#link2HCH0009"> CHAPTER IX. SELECTION OF THE MOTOR. </a> + </p> + <p class="toc"> + <a href="#link2HCH0010"> CHAPTER X. PROPER DIMENSIONS OF MACHINES. </a> + </p> + <p class="toc"> + <a href="#link2HCH0011"> CHAPTER XI. PLANE AND RUDDER CONTROL. </a> + </p> + <p class="toc"> + <a href="#link2HCH0012"> CHAPTER XII. HOW TO USE THE MACHINE. </a> + </p> + <p class="toc"> + <a href="#link2HCH0013"> CHAPTER XIII. PECULIARITIES OF AIRSHIP POWER. + </a> + </p> + <p class="toc"> + <a href="#link2HCH0014"> CHAPTER XIV. ABOUT WIND CURRENTS, ETC. </a> + </p> + <p class="toc"> + <a href="#link2HCH0015"> CHAPTER XV. THE ELEMENT OF DANGER. </a> + </p> + <p class="toc"> + <a href="#link2HCH0016"> CHAPTER XVI. RADICAL CHANGES BEING MADE. </a> + </p> + <p class="toc"> + <a href="#link2HCH0017"> CHAPTER XVII. SOME OF THE NEW DESIGNS. </a> + </p> + <p class="toc"> + <a href="#link2HCH0018"> CHAPTER XVIII. DEMAND FOR FLYING MACHINES. </a> + </p> + <p class="toc"> + <a href="#link2HCH0019"> CHAPTER XIX. LAW OF THE AIRSHIP. </a> + </p> + <p class="toc"> + <a href="#link2HCH0020"> CHAPTER XX. SOARING FLIGHT. </a> + </p> + <p class="toc"> + <a href="#link2HCH0021"> CHAPTER XXI. FLYING MACHINES VS. BALLOONS. </a> + </p> + <p class="toc"> + <a href="#link2HCH0022"> CHAPTER XXII. PROBLEMS OF AERIAL FLIGHT. </a> + </p> + <p class="toc"> + <a href="#link2HCH0023"> CHAPTER XXIII. AMATEURS MAY USE WRIGHT PATENTS. + </a> + </p> + <p class="toc"> + <a href="#link2HCH0024"> CHAPTER XXIV. HINTS ON PROPELLER CONSTRUCTION. + </a> + </p> + <p class="toc"> + <a href="#link2HCH0025"> CHAPTER XXV. NEW MOTORS AND DEVICES. </a> + </p> + <p class="toc"> + <a href="#link2HCH0026"> CHAPTER XXVI. MONOPLANES, TRIPLANES, + MULTIPLANES. </a> + </p> + <p class="toc"> + <a href="#link2HCH0027"> CHAPTER XXVII. 1911 AEROPLANE RECORDS. </a> + </p> + <p class="toc"> + <a href="#link2H_NOTA"> NOTABLE CROSS-COUNTRY FLIGHTS OF 1911. </a> + </p> + <p class="toc"> + <a href="#link2HCH0028"> CHAPTER XXVIII. GLOSSARY OF AERONAUTICAL TERMS. + </a> + </p> + <p> + <br /> + </p> + <p class="toc"> + <a href="#link2H_FOOT"> Footnotes: </a> + </p> + </blockquote> + <p> + <br /> <br /> + </p> + <hr /> + <p> + <br /> <br /> <a name="link2H_4_0003" id="link2H_4_0003"> + <!-- H2 anchor --> </a> + </p> + <h1> + FLYING MACHINES: CONSTRUCTION and OPERATION + </h1> + <p> + <a name="link2HCH0001" id="link2HCH0001"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER I. EVOLUTION OF TWO-SURFACE FLYING MACHINE. + </h2> + <h3> + By Octave Chanute. + </h3> + <p> + I am asked to set forth the development of the "two-surface" type of + flying machine which is now used with modifications by Wright Brothers, + Farman, <a href="#linknote-1" name="linknoteref-1" id="linknoteref-1"><small>1</small></a> + Delagrange, Herring and others. + </p> + <p> + This type originated with Mr. F. H. Wenham, who patented it in England in + 1866 (No. 1571), taking out provisional papers only. In the abridgment of + British patent Aeronautical Specifications (1893) it is described as + follows: + </p> + <p> + "Two or more aeroplanes are arranged one above the other, and support a + framework or car containing the motive power. The aeroplanes are made of + silk or canvas stretched on a frame by wooden rods or steel ribs. When + manual power is employed the body is placed horizontally, and oars or + propellers are actuated by the arms or legs. + </p> + <p> + "A start may be obtained by lowering the legs and running down hill or the + machine may be started from a moving carriage. One or more screw + propellers may be applied for propelling when steam power is employed." + </p> + <p> + On June 27, 1866, Mr. Wenham read before the "Aeronautical Society of + Great Britain," then recently organized, the ablest paper ever presented + to that society, and thereby breathed into it a spirit which has continued + to this day. In this paper he described his observations of birds, + discussed the laws governing flight as to the surfaces and power required + both with wings and screws, and he then gave an account of his own + experiments with models and with aeroplanes of sufficient size to carry + the weight of a man. + </p> + <p> + Second Wenham Aeroplane. + </p> + <p> + His second aeroplane was sixteen feet from tip to tip. A trussed spar at + the bottom carried six superposed bands of thin holland fabric fifteen + inches wide, connected with vertical webs of holland two feet apart, thus + virtually giving a length of wing of ninety-six feet and one hundred and + twenty square feet of supporting surface. The man was placed horizontally + on a base board beneath the spar. This apparatus when tried in the wind + was found to be unmanageable by reason of the fluttering motions of the + fabric, which was insufficiently stiffened with crinoline steel, but Mr. + Wenham pointed out that this in no way invalidated the principle of the + apparatus, which was to obtain large supporting surfaces without + increasing unduly the leverage and consequent weight of spar required, by + simply superposing the surfaces. + </p> + <p> + This principle is entirely sound and it is surprising that it is, to this + day, not realized by those aviators who are hankering for monoplanes. + </p> + <p> + Experiments by Stringfellow. + </p> + <p> + The next man to test an apparatus with superposed surfaces was Mr. + Stringfellow, who, becoming much impressed with Mr. Wenham's proposal, + produced a largish model at the exhibition of the Aeronautical Society in + 1868. It consisted of three superposed surfaces aggregating 28 square feet + and a tail of 8 square feet more. The weight was under 12 pounds and it + was driven by a central propeller actuated by a steam engine overestimated + at one-third of a horsepower. It ran suspended to a wire on its trials but + failed of free flight, in consequence of defective equilibrium. This + apparatus has since been rebuilt and is now in the National Museum of the + Smithsonian Institution at Washington. Linfield's Unsuccessful Efforts. + </p> + <p> + In 1878 Mr. Linfield tested an apparatus in England consisting of a + cigar-shaped car, to which was attached on each side frames five feet + square, containing each twenty-five superposed planes of stretched and + varnished linen eighteen inches wide, and only two inches apart, thus + reminding one of a Spanish donkey with panniers. The whole weighed two + hundred and forty pounds. This was tested by being mounted on a flat car + behind a locomotive going 40 miles an hour. When towed by a line fifteen + feet long the apparatus rose only a little from the car and exhibited such + unstable equilibrium that the experiment was not renewed. The lift was + only about one-third of what it would have been had the planes been + properly spaced, say their full width apart, instead of one-ninth as + erroneously devised. + </p> + <p> + Renard's "Dirigible Parachute." + </p> + <p> + In 1889 Commandant Renard, the eminent superintendent of the French + Aeronautical Department, exhibited at the Paris Exposition of that year, + an apparatus experimented with some years before, which he termed a + "dirigible parachute." It consisted of an oviform body to which were + pivoted two upright slats carrying above the body nine long superposed + flat blades spaced about one-third of their width apart. When this + apparatus was properly set at an angle to the longitudinal axis of the + body and dropped from a balloon, it travelled back against the wind for a + considerable distance before alighting. The course could be varied by a + rudder. No practical application seems to have been made of this device by + the French War Department, but Mr. J. P. Holland, the inventor of the + submarine boat which bears his name, proposed in 1893 an arrangement of + pivoted framework attached to the body of a flying machine which combines + the principle of Commandant Renard with the curved blades experimented + with by Mr. Phillips, now to be noticed, with the addition of lifting + screws inserted among the blades. + </p> + <p> + Phillips Fails on Stability Problem. + </p> + <p> + In 1893 Mr. Horatio Phillips, of England, after some very interesting + experiments with various wing sections, from which he deduced conclusions + as to the shape of maximum lift, tested an apparatus resembling a Venetian + blind which consisted of fifty wooden slats of peculiar shape, 22 feet + long, one and a half inches wide, and two inches apart, set in ten + vertical upright boards. All this was carried upon a body provided with + three wheels. It weighed 420 pounds and was driven at 40 miles an hour on + a wooden sidewalk by a steam engine of nine horsepower which actuated a + two-bladed screw. The lift was satisfactory, being perhaps 70 pounds per + horsepower, but the equilibrium was quite bad and the experiments were + discontinued. They were taken up again in 1904 with a similar apparatus + large enough to carry a passenger, but the longitudinal equilibrium was + found to be defective. Then in 1907 a new machine was tested, in which + four sets of frames, carrying similar sets of slat "sustainers" were + inserted, and with this arrangement the longitudinal stability was found + to be very satisfactory. The whole apparatus, with the operator, weighed + 650 pounds. It flew about 200 yards when driven by a motor of 20 to 22 + h.p. at 30 miles an hour, thus exhibiting a lift of about 32 pounds per + h.p., while it will be remembered that the aeroplane of Wright Brothers + exhibits a lifting capacity of 50 pounds to the h.p. + </p> + <p> + Hargrave's Kite Experiments. + </p> + <p> + After experimenting with very many models and building no less than + eighteen monoplane flying model machines, actuated by rubber, by + compressed air and by steam, Mr. Lawrence Hargrave, of Sydney, New South + Wales, invented the cellular kite which bears his name and made it known + in a paper contributed to the Chicago Conference on Aerial Navigation in + 1893, describing several varieties. The modern construction is well known, + and consists of two cells, each of superposed surfaces with vertical side + fins, placed one behind the other and connected by a rod or frame. This + flies with great steadiness without a tail. Mr. Hargrave's idea was to use + a team of these kites, below which he proposed to suspend a motor and + propeller from which a line would be carried to an anchor in the ground. + Then by actuating the propeller the whole apparatus would move forward, + pick up the anchor and fly away. He said: "The next step is clear enough, + namely, that a flying machine with acres of surface can be safely got + under way or anchored and hauled to the ground by means of the string of + kites." + </p> + <p> + The first tentative experiments did not result well and emphasized the + necessity for a light motor, so that Mr. Hargrave has since been engaged + in developing one, not having convenient access to those which have been + produced by the automobile designers and builders. + </p> + <p> + Experiments With Glider Model. + </p> + <p> + And here a curious reminiscence may be indulged in. In 1888 the present + writer experimented with a two-cell gliding model, precisely similar to a + Hargrave kite, as will be confirmed by Mr. Herring. It was frequently + tested by launching from the top of a three-story house and glided + downward very steadily in all sorts of breezes, but the angle of descent + was much steeper than that of birds, and the weight sustained per square + foot was less than with single cells, in consequence of the lesser support + afforded by the rear cell, which operated upon air already set in motion + downward by the front cell, so nothing more was done with it, for it never + occurred to the writer to try it as a kite and he thus missed the + distinction which attaches to Hargrave's name. + </p> + <p> + Sir Hiram Maxim also introduced fore and aft superposed surfaces in his + wondrous flying machine of 1893, but he relied chiefly for the lift upon + his main large surface and this necessitated so many guys, to prevent + distortion, as greatly to increase the head resistance and this, together + with the unstable equilibrium, made it evident that the design of the + machine would have to be changed. + </p> + <p> + How Lilienthal Was Killed. + </p> + <p> + In 1895, Otto Lilienthal, the father of modern aviation, the man to whose + method of experimenting almost all present successes are due, after making + something like two thousand glides with monoplanes, added a superposed + surface to his apparatus and found the control of it much improved. The + two surfaces were kept apart by two struts or vertical posts with a few + guy wires, but the connecting joints were weak and there was nothing like + trussing. This eventually cost his most useful life. Two weeks before that + distressing loss to science, Herr Wilhelm Kress, the distinguished and + veteran aviator of Vienna, witnessed a number of glides by Lilienthal with + his double-decked apparatus. He noticed that it was much wracked and + wobbly and wrote to me after the accident: "The connection of the wings + and the steering arrangement were very bad and unreliable. I warned Herr + Lilienthal very seriously. He promised me that he would soon put it in + order, but I fear that he did not attend to it immediately." + </p> + <p> + In point of fact, Lilienthal had built a new machine, upon a different + principle, from which he expected great results, and intended to make but + very few more flights with the old apparatus. He unwisely made one too + many and, like Pilcher, was the victim of a distorted apparatus. Probably + one of the joints of the struts gave way, the upper surface blew back and + Lilienthal, who was well forward on the lower surface, was pitched + headlong to destruction. + </p> + <p> + Experiments by the Writer. + </p> + <p> + In 1896, assisted by Mr. Herring and Mr. Avery, I experimented with + several full sized gliding machines, carrying a man. The first was a + Lilienthal monoplane which was deemed so cranky that it was discarded + after making about one hundred glides, six weeks before Lilienthal's + accident. The second was known as the multiple winged machine and finally + developed into five pairs of pivoted wings, trussed together at the front + and one pair in the rear. It glided at angles of descent of 10 or 11 + degrees or of one in five, and this was deemed too steep. Then Mr. Herring + and myself made computations to analyze the resistances. We attributed + much of them to the five front spars of the wings and on a sheet of + cross-barred paper I at once drew the design for a new three-decked + machine to be built by Mr. Herring. + </p> + <p> + Being a builder of bridges, I trussed these surfaces together, in order to + obtain strength and stiffness. When tested in gliding flight the lower + surface was found too near the ground. It was taken off and the remaining + apparatus now consisted of two surfaces connected together by a girder + composed of vertical posts and diagonal ties, specifically known as a + "Pratt truss." Then Mr. Herring and Mr. Avery together devised and put on + an elastic attachment to the tail. This machine proved a success, it being + safe and manageable. Over 700 glides were made with it at angles of + descent of 8 to 10 degrees, or one in six to one in seven. + </p> + <p> + First Proposed by Wenham. + </p> + <p> + The elastic tail attachment and the trussing of the connecting frame of + the superposed wings were the only novelties in this machine, for the + superposing of the surfaces had first been proposed by Wenham, but in + accordance with the popular perception, which bestows all the credit upon + the man who adds the last touch making for success to the labors of his + predecessors, the machine has since been known by many persons as the + "Chanute type" of gliders, much to my personal gratification. + </p> + <p> + It has since been improved in many ways. Wright Brothers, disregarding the + fashion which prevails among birds, have placed the tail in front of their + apparatus and called it a front rudder, besides placing the operator in + horizontal position instead of upright, as I did; and also providing a + method of warping the wings to preserve equilibrium. Farman and + Delagrange, under the very able guidance and constructive work of Voisin + brothers, then substituted many details, including a box tail for the + dart-like tail which I used. This may have increased the resistance, but + it adds to the steadiness. Now the tendency in France seems to be to go + back to the monoplane. + </p> + <p> + Monoplane Idea Wrong. + </p> + <p> + The advocates of the single supporting surface are probably mistaken. It + is true that a single surface shows a greater lift per square foot than + superposed surfaces for a given speed, but the increased weight due to + leverage more than counterbalances this advantage by requiring heavy spars + and some guys. I believe that the future aeroplane dynamic flier will + consist of superposed surfaces, and, now that it has been found that by + imbedding suitably shaped spars in the cloth the head resistance may be + much diminished, I see few objections to superposing three, four or even + five surfaces properly trussed, and thus obtaining a compact, handy, + manageable and comparatively light apparatus. <a href="#linknote-2" + name="linknoteref-2" id="linknoteref-2"><small>2</small></a> + </p> + <p> + <a name="link2HCH0002" id="link2HCH0002"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER II. THEORY, DEVELOPMENT, AND USE. + </h2> + <p> + While every craft that navigates the air is an airship, all airships are + not flying machines. The balloon, for instance, is an airship, but it is + not what is known among aviators as a flying machine. This latter term is + properly used only in referring to heavier-than-air machines which have no + gas-bag lifting devices, and are made to really fly by the application of + engine propulsion. + </p> + <p> + Mechanical Birds. + </p> + <p> + All successful flying machines—and there are a number of them—are + based on bird action. The various designers have studied bird flight and + soaring, mastered its technique as devised by Nature, and the modern + flying machine is the result. On an exaggerated, enlarged scale the + machines which are now navigating the air are nothing more nor less than + mechanical birds. + </p> + <p> + Origin of the Aeroplane. + </p> + <p> + Octave Chanute, of Chicago, may well be called "the developer of the + flying machine." Leaving balloons and various forms of gas-bags out of + consideration, other experimenters, notably Langley and Lilienthal, + antedated him in attempting the navigation of the air on aeroplanes, or + flying machines, but none of them were wholly successful, and it remained + for Chanute to demonstrate the practicability of what was then called the + gliding machine. This term was adopted because the apparatus was, as the + name implies, simply a gliding machine, being without motor propulsion, + and intended solely to solve the problem of the best form of construction. + The biplane, used by Chanute in 1896, is still the basis of most + successful flying machines, the only radical difference being that motors, + rudders, etc., have been added. + </p> + <p> + Character of Chanute's Experiments. + </p> + <p> + It was the privilege of the author of this book to be Mr. Chanute's guest + at Millers, Indiana, in 1896, when, in collaboration with Messrs. Herring + and Avery, he was conducting the series of experiments which have since + made possible the construction of the modern flying machine which such + successful aviators as the Wright brothers and others are now using. It + was a wild country, much frequented by eagles, hawks, and similar birds. + The enthusiastic trio, Chanute, Herring and Avery, would watch for hours + the evolutions of some big bird in the air, agreeing in the end on the + verdict, "When we master the principle of that bird's soaring without wing + action, we will have come close to solving the problem of the flying + machine." + </p> + <p> + Aeroplanes of various forms were constructed by Mr. Chanute with the + assistance of Messrs. Herring and Avery until, at the time of the writer's + visit, they had settled upon the biplane, or two-surface machine. Mr. + Herring later equipped this with a rudder, and made other additions, but + the general idea is still the basis of the Wright, Curtiss, and other + machines in which, by the aid of gasolene motors, long flights have been + made. + </p> + <p> + Developments by the Wrights. + </p> + <p> + In 1900 the Wright brothers, William and Orville, who were then in the + bicycle business in Dayton, Ohio, became interested in Chanute's + experiments and communicated with him. The result was that the Wrights + took up Chanute's ideas and developed them further, making many additions + of their own, one of which was the placing of a rudder in front, and the + location of the operator horizontally on the machine, thus diminishing by + four-fifths the wind resistance of the man's body. For three years the + Wrights experimented with the glider before venturing to add a motor, + which was not done until they had thoroughly mastered the control of their + movements in the air. + </p> + <p> + Limits of the Flying Machine. + </p> + <p> + In the opinion of competent experts it is idle to look for a commercial + future for the flying machine. There is, and always will be, a limit to + its carrying capacity which will prohibit its employment for passenger or + freight purposes in a wholesale or general way. There are some, of course, + who will argue that because a machine will carry two people another may be + constructed that will carry a dozen, but those who make this contention do + not understand the theory of weight sustentation in the air; or that the + greater the load the greater must be the lifting power (motors and plane + surface), and that there is a limit to these—as will be explained + later on—beyond which the aviator cannot go. + </p> + <p> + Some Practical Uses. + </p> + <p> + At the same time there are fields in which the flying machine may be used + to great advantage. These are: + </p> + <p> + Sports—Flying machine races or flights will always be popular by + reason of the element of danger. It is a strange, but nevertheless a true + proposition, that it is this element which adds zest to all sporting + events. + </p> + <p> + Scientific—For exploration of otherwise inaccessible regions such as + deserts, mountain tops, etc. + </p> + <p> + Reconnoitering—In time of war flying machines may be used to + advantage to spy out an enemy's encampment, ascertain its defenses, etc. + </p> + <p> + <a name="link2HCH0003" id="link2HCH0003"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER III. MECHANICAL BIRD ACTION + </h2> + <p> + In order to understand the theory of the modern flying machine one must + also understand bird action and wind action. In this connection the + following simple experiment will be of interest: + </p> + <p> + Take a circular-shaped bit of cardboard, like the lid of a hat box, and + remove the bent-over portion so as to have a perfectly flat surface with a + clean, sharp edge. Holding the cardboard at arm's length, withdraw your + hand, leaving the cardboard without support. What is the result? The + cardboard, being heavier than air, and having nothing to sustain it, will + fall to the ground. Pick it up and throw it, with considerable force, + against the wind edgewise. What happens? Instead of falling to the ground, + the cardboard sails along on the wind, remaining afloat so long as it is + in motion. It seeks the ground, by gravity, only as the motion ceases, and + then by easy stages, instead of dropping abruptly as in the first + instance. + </p> + <p> + Here we have a homely, but accurate illustration of the action of the + flying machine. The motor does for the latter what the force of your arm + does for the cardboard—imparts a motion which keeps it afloat. The + only real difference is that the motion given by the motor is continuous + and much more powerful than that given by your arm. The action of the + latter is limited and the end of its propulsive force is reached within a + second or two after it is exerted, while the action of the motor is + prolonged. + </p> + <p> + Another Simple Illustration. + </p> + <p> + Another simple means of illustrating the principle of flying machine + operation, so far as sustentation and the elevation and depression of the + planes is concerned, is explained in the accompanying diagram. + </p> + <p> + A is a piece of cardboard about 2 by 3 inches in size. B is a piece of + paper of the same size pasted to one edge of A. If you bend the paper to a + curve, with convex side up and blow across it as shown in Figure C, the + paper will rise instead of being depressed. The dotted lines show that the + air is passing over the top of the curved paper and yet, no matter how + hard you may blow, the effect will be to elevate the paper, despite the + fact that the air is passing over, instead of under the curved surface. + </p> + <p> + In Figure D we have an opposite effect. Here the paper is in a curve + exactly the reverse of that shown in Figure C, bringing the concave side + up. Now if you will again blow across the surface of the card the action + of the paper will be downward—it will be impossible to make it rise. + The harder you blow the greater will be the downward movement. + </p> + <p> + Principle In General Use. + </p> + <p> + This principle is taken advantage of in the construction of all successful + flying machines. Makers of monoplanes and biplanes alike adhere to curved + bodies, with the concave surface facing downward. Straight planes were + tried for a time, but found greatly lacking in the power of sustentation. + By curving the planes, and placing the concave surface downward, a sort of + inverted bowl is formed in which the air gathers and exerts a buoyant + effect. Just what the ratio of the curve should be is a matter of + contention. In some instances one inch to the foot is found to be + satisfactory; in others this is doubled, and there are a few cases in + which a curve of as much as 3 inches to the foot has been used. + </p> + <p> + Right here it might be well to explain that the word "plane" applied to + flying machines of modern construction is in reality a misnomer. Plane + indicates a flat, level surface. As most successful flying machines have + curved supporting surfaces it is clearly wrong to speak of "planes," or + "aeroplanes." Usage, however, has made the terms convenient and, as they + are generally accepted and understood by the public, they are used in like + manner in this volume. + </p> + <p> + Getting Under Headway. + </p> + <p> + A bird, on first rising from the ground, or beginning its flight from a + tree, will flap its wings to get under headway. Here again we have another + illustration of the manner in which a flying machine gets under headway—the + motor imparts the force necessary to put the machine into the air, but + right here the similarity ceases. If the machine is to be kept afloat the + motor must be kept moving. A flying machine will not sustain itself; it + will not remain suspended in the air unless it is under headway. This is + because it is heavier than air, and gravity draws it to the ground. + </p> + <p> + Puzzle in Bird Soaring. + </p> + <p> + But a bird, which is also heavier than air, will remain suspended, in a + calm, will even soar and move in a circle, without apparent movement of + its wings. This is explained on the theory that there are generally + vertical columns of air in circulation strong enough to sustain a bird, + but much too weak to exert any lifting power on a flying machine, It is + easy to understand how a bird can remain suspended when the wind is in + action, but its suspension in a seeming dead calm was a puzzle to + scientists until Mr. Chanute advanced the proposition of vertical columns + of air. + </p> + <p> + Modeled Closely After Birds. + </p> + <p> + So far as possible, builders of flying machines have taken what may be + called "the architecture" of birds as a model. This is readily noticeable + in the form of construction. When a bird is in motion its wings (except + when flapping) are extended in a straight line at right angles to its + body. This brings a sharp, thin edge against the air, offering the least + possible surface for resistance, while at the same time a broad surface + for support is afforded by the flat, under side of the wings. Identically + the same thing is done in the construction of the flying machine. + </p> + <p> + Note, for instance, the marked similarity in form as shown in the + illustration in Chapter II. Here A is the bird, and B the general outline + of the machine. The thin edge of the plane in the latter is almost a + duplicate of that formed by the outstretched wings of the bird, while the + rudder plane in the rear serves the same purpose as the bird's tail. + </p> + <p> + <a name="link2HCH0004" id="link2HCH0004"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER IV. VARIOUS FORMS OF FLYING MACHINES. + </h2> + <p> + There are three distinct and radically different forms of flying machines. + These are: + </p> + <p> + Aeroplanes, helicopters and ornithopers. + </p> + <p> + Of these the aeroplane takes precedence and is used almost exclusively by + successful aviators, the helicopters and ornithopers having been tried and + found lacking in some vital features, while at the same time in some + respects the helicopter has advantages not found in the aeroplane. + </p> + <p> + What the Helicopter Is. + </p> + <p> + The helicopter gets its name from being fitted with vertical propellers or + helices (see illustration) by the action of which the machine is raised + directly from the ground into the air. This does away with the necessity + for getting the machine under a gliding headway before it floats, as is + the case with the aeroplane, and consequently the helicopter can be + handled in a much smaller space than is required for an aeroplane. This, + in many instances, is an important advantage, but it is the only one the + helicopter possesses, and is more than overcome by its drawbacks. The most + serious of these is that the helicopter is deficient in sustaining + capacity, and requires too much motive power. + </p> + <p> + Form of the Ornithopter. + </p> + <p> + The ornithopter has hinged planes which work like the wings of a bird. At + first thought this would seem to be the correct principle, and most of the + early experimenters conducted their operations on this line. It is now + generally understood, however, that the bird in soaring is in reality an + aeroplane, its extended wings serving to sustain, as well as propel, the + body. At any rate the ornithoper has not been successful in aviation, and + has been interesting mainly as an ingenious toy. Attempts to construct it + on a scale that would permit of its use by man in actual aerial flights + have been far from encouraging. + </p> + <p> + Three Kinds of Aeroplanes. + </p> + <p> + There are three forms of aeroplanes, with all of which more or less + success has been attained. These are: + </p> + <p> + The monoplane, a one-surfaced plane, like that used by Bleriot. + </p> + <p> + The biplane, a two-surfaced plane, now used by the Wrights, Curtiss, + Farman, and others. + </p> + <p> + The triplane, a three-surfaced plane This form is but little used, its + only prominent advocate at present being Elle Lavimer, a Danish + experimenter, who has not thus far accomplished much. + </p> + <p> + Whatever of real success has been accomplished in aviation may be credited + to the monoplane and biplane, with the balance in favor of the latter. The + monoplane is the more simple in construction and, where weight-sustaining + capacity is not a prime requisite, may probably be found the most + convenient. This opinion is based on the fact that the smaller the surface + of the plane the less will be the resistance offered to the air, and the + greater will be the speed at which the machine may be moved. On the other + hand, the biplane has a much greater plane surface (double that of a + monoplane of the same size) and consequently much greater weight-carrying + capacity. + </p> + <p> + Differences in Biplanes. + </p> + <p> + While all biplanes are of the same general construction so far as the main + planes are concerned, each aviator has his own ideas as to the "rigging." + </p> + <p> + Wright, for instance, places a double horizontal rudder in front, with a + vertical rudder in the rear. There are no partitions between the main + planes, and the bicycle wheels used on other forms are replaced by skids. + </p> + <p> + Voisin, on the contrary, divides the main planes with vertical partitions + to increase stability in turning; uses a single-plane horizontal rudder in + front, and a big box-tail with vertical rudder at the rear; also the + bicycle wheels. + </p> + <p> + Curtiss attaches horizontal stabilizing surfaces to the upper plane; has a + double horizontal rudder in front, with a vertical rudder and horizontal + stabilizing surfaces in rear. Also the bicycle wheel alighting gear. + </p> + <p> + <a name="link2HCH0005" id="link2HCH0005"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER V. CONSTRUCTING A GLIDING MACHINE. + </h2> + <p> + First decide upon the kind of a machine you want—monoplane, biplane, + or triplane. For a novice the biplane will, as a rule, be found the most + satisfactory as it is more compact and therefore the more easily handled. + This will be easily understood when we realize that the surface of a + flying machine should be laid out in proportion to the amount of weight it + will have to sustain. The generally accepted rule is that 152 square feet + of surface will sustain the weight of an average-sized man, say 170 + pounds. Now it follows that if these 152 square feet of surface are used + in one plane, as in the monoplane, the length and width of this plane must + be greater than if the same amount of surface is secured by using two + planes—the biplane. This results in the biplane being more compact + and therefore more readily manipulated than the monoplane, which is an + important item for a novice. + </p> + <p> + Glider the Basis of Success. + </p> + <p> + Flying machines without motors are called gliders. In making a flying + machine you first construct the glider. If you use it in this form it + remains a glider. If you install a motor it becomes a flying machine. You + must have a good glider as the basis of a successful flying machine. + </p> + <p> + It will be well for the novice, the man who has never had any experience + as an aviator, to begin with a glider and master its construction and + operation before he essays the more pretentious task of handling a + fully-equipped flying machine. In fact, it is essential that he should do + so. + </p> + <p> + Plans for Handy Glider. + </p> + <p> + A glider with a spread (advancing edge) of 20 feet, and a breadth or depth + of 4 feet, will be about right to begin with. Two planes of this size will + give the 152 square yards of surface necessary to sustain a man's weight. + Remember that in referring to flying machine measurements "spread" takes + the place of what would ordinarily be called "length," and invariably + applies to the long or advancing edge of the machine which cuts into the + air. Thus, a glider is spoken of as being 20 feet spread, and 4 feet in + depth. So far as mastering the control of the machine is concerned, + learning to balance one's self in the air, guiding the machine in any + desired direction by changing the position of the body, etc., all this may + be learned just as readily, and perhaps more so, with a 20-foot glider + than with a larger apparatus. + </p> + <p> + Kind of Material Required. + </p> + <p> + There are three all-important features in flying machine construction, + viz.: lightness, strength and extreme rigidity. Spruce is the wood + generally used for glider frames. Oak, ash and hickory are all stronger, + but they are also considerably heavier, and where the saving of weight is + essential, the difference is largely in favor of spruce. This will be seen + in the following table: + </p> +<pre xml:space="preserve"> + Weight Tensile Compressive + per cubic ft. Strength Strength + Wood in lbs. lbs. per sq. in. lbs. per sq in. + Hickory 53 12,000 8,500 + Oak 50 12,000 9,000 + Ash 38 12,000 6,000 + Walnut 38 8,000 6,000 + Spruce 25 8,000 5,000 + Pine 25 5,000 4,500 +</pre> + <p> + Considering the marked saving in weight spruce has a greater percentage of + tensile strength than any of the other woods. It is also easier to find in + long, straight-grained pieces free from knots, and it is this kind only + that should be used in flying machine construction. + </p> + <p> + You will next need some spools or hanks of No. 6 linen shoe thread, metal + sockets, a supply of strong piano wire, a quantity of closely-woven silk + or cotton cloth, glue, turnbuckles, varnish, etc. + </p> + <p> + Names of the Various Parts. + </p> + <p> + The long strips, four in number, which form the front and rear edges of + the upper and lower frames, are called the horizontal beams. These are + each 20 feet in length. These horizontal beams are connected by upright + strips, 4 feet long, called stanchions. There are usually 12 of these, six + on the front edge, and six on the rear. They serve to hold the upper plane + away from the lower one. Next comes the ribs. These are 4 feet in length + (projecting for a foot over the rear beam), and while intended principally + as a support to the cloth covering of the planes, also tend to hold the + frame together in a horizontal position just as the stanchions do in the + vertical. There are forty-one of these ribs, twenty-one on the upper and + twenty on the lower plane. Then come the struts, the main pieces which + join the horizontal beams. All of these parts are shown in the + illustrations, reference to which will make the meaning of the various + names clear. + </p> + <p> + Quantity and Cost of Material. + </p> + <p> + For the horizontal beams four pieces of spruce, 20 feet long, 1 1/2 inches + wide and 3/4 inch thick are necessary. These pieces must be + straight-grain, and absolutely free from knots. If it is impossible to + obtain clear pieces of this length, shorter ones may be spliced, but this + is not advised as it adds materially to the weight. The twelve stanchions + should be 4 feet long and 7/8 inch in diameter and rounded in form so as + to offer as little resistance as possible to the wind. The struts, there + are twelve of them, are 3 feet long by 11/4 x 1/2 inch. For a 20-foot + biplane about 20 yards of stout silk or unbleached muslin, of standard one + yard width, will be needed. The forty-one ribs are each 4 feet long, and + 1/2 inch square. A roll of No. 12 piano wire, twenty-four sockets, a + package of small copper tacks, a pot of glue, and similar accessories will + be required. The entire cost of this material should not exceed $20. The + wood and cloth will be the two largest items, and these should not cost + more than $10. This leaves $10 for the varnish, wire, tacks, glue, and + other incidentals. This estimate is made for cost of materials only, it + being taken for granted that the experimenter will construct his own + glider. Should the services of a carpenter be required the total cost will + probably approximate $60 or $70. + </p> + <p> + Application of the Rudders. + </p> + <p> + The figures given also include the expense of rudders, but the details of + these have not been included as the glider is really complete without + them. Some of the best flights the writer ever saw were made by Mr. A. M. + Herring in a glider without a rudder, and yet there can be no doubt that a + rudder, properly proportioned and placed, especially a rear rudder, is of + great value to the aviator as it keeps the machine with its head to the + wind, which is the only safe position for a novice. For initial + educational purposes, however, a rudder is not essential as the glides + will, or should, be made on level ground, in moderate, steady wind + currents, and at a modest elevation. The addition of a rudder, therefore, + may well be left until the aviator has become reasonably expert in the + management of his machine. + </p> + <p> + Putting the Machine Together. + </p> + <p> + Having obtained the necessary material, the first move is to have the rib + pieces steamed and curved. This curve may be slight, about 2 inches for + the 4 feet. While this is being done the other parts should be carefully + rounded so the square edges will be taken off. This may be done with sand + paper. Next apply a coat of shellac, and when dry rub it down thoroughly + with fine sand paper. When the ribs are curved treat them in the same way. + </p> + <p> + Lay two of the long horizontal frame pieces on the floor 3 feet apart. + Between these place six of the strut pieces. Put one at each end, and each + 4 1/2 feet put another, leaving a 2-foot space in the center. This will + give you four struts 4 1/2 feet apart, and two in the center 2 feet apart, + as shown in the illustration. This makes five rectangles. Be sure that the + points of contact are perfect, and that the struts are exactly at right + angles with the horizontal frames. This is a most important feature + because if your frame "skews" or twists you cannot keep it straight in the + air. Now glue the ends of the struts to the frame pieces, using plenty of + glue, and nail on strips that will hold the frame in place while the glue + is drying. The next day lash the joints together firmly with the shoe + thread, winding it as you would to mend a broken gun stock, and over each + layer put a coating of glue. This done, the other frame pieces and struts + may be treated in the same way, and you will thus get the foundations for + the two planes. + </p> + <p> + Another Way of Placing Struts. + </p> + <p> + In the machines built for professional use a stronger and more certain + form of construction is desired. This is secured by the placing the struts + for the lower plane under the frame piece, and those for the upper plane + over it, allowing them in each instance to come out flush with the outer + edges of the frame pieces. They are then securely fastened with a tie + plate or clamp which passes over the end of the strut and is bound firmly + against the surface of the frame piece by the eye bolts of the stanchion + sockets. + </p> + <p> + Placing the Rib Pieces. + </p> + <p> + Take one of the frames and place on it the ribs, with the arched side up, + letting one end of the ribs come flush with the front edge of the forward + frame, and the other end projecting about a foot beyond the rear frame. + The manner of fastening the ribs to the frame pieces is optional. In some + cases they are lashed with shoe thread, and in others clamped with a metal + clamp fastened with 1/2-inch wood screws. Where clamps and screws are used + care should be taken to make slight holes in the wood with an awl before + starting the screws so as to lessen any tendency to split the wood. On the + top frame, twenty-one ribs placed one foot apart will be required. On the + lower frame, because of the opening left for the operator's body, you will + need only twenty. + </p> + <p> + Joining the Two Frames. + </p> + <p> + The two frames must now be joined together. For this you will need + twenty-four aluminum or iron sockets which may be purchased at a foundry + or hardware shop. These sockets, as the name implies, provide a receptacle + in which the end of a stanchion is firmly held, and have flanges with + holes for eye-bolts which hold them firmly to the frame pieces, and also + serve to hold the guy wires. In addition to these eye-bolt holes there are + two others through which screws are fastened into the frame pieces. On the + front frame piece of the bottom plane place six sockets, beginning at the + end of the frame, and locating them exactly opposite the struts. Screw the + sockets into position with wood screws, and then put the eye-bolts in + place. Repeat the operation on the rear frame. Next put the sockets for + the upper plane frame in place. + </p> + <p> + You are now ready to bring the two planes together. Begin by inserting the + stanchions in the sockets in the lower plane. The ends may need a little + rubbing with sandpaper to get them into the sockets, but care must be + taken to have them fit snugly. When all the stanchions are in place on the + lower plane, lift the upper plane into position, and fit the sockets over + the upper ends of the stanchions. + </p> + <p> + Trussing with Guy Wires. + </p> + <p> + The next move is to "tie" the frame together rigidly by the aid of guy + wires. This is where the No. 12 piano wire comes in. Each rectangle formed + by the struts and stanchions with the exception of the small center one, + is to be wired separately as shown in the illustration. At each of the + eight corners forming the rectangle the ring of one of the eye-bolts will + be found. There are two ways of doing this "tieing," or trussing. One is + to run the wires diagonally from eye-bolt to eye-bolt, depending upon main + strength to pull them taut enough, and then twist the ends so as to hold. + The other is to first make a loop of wire at each eye-bolt, and connect + these loops to the main wires with turn-buckles. This latter method is the + best, as it admits of the tension being regulated by simply turning the + buckle so as to draw the ends of the wire closer together. A glance at the + illustration will make this plain, and also show how the wires are to be + placed. The proper degree of tension may be determined in the following + manner: + </p> + <p> + After the frame is wired place each end on a saw-horse so as to lift the + entire frame clear of the work-shop floor. Get under it, in the center + rectangle and, grasping the center struts, one in each hand, put your + entire weight on the structure. If it is properly put together it will + remain rigid and unyielding. Should it sag ever so slightly the tension of + the wires must be increased until any tendency to sag, no matter how + slight it may be, is overcome. + </p> + <p> + Putting on the Cloth. + </p> + <p> + We are now ready to put on the cloth covering which holds the air and + makes the machine buoyant. The kind of material employed is of small + account so long as it is light, strong, and wind-proof, or nearly so. Some + aviators use what is called rubberized silk, others prefer balloon cloth. + Ordinary muslin of good quality, treated with a coat of light varnish + after it is in place, will answer all the purposes of the amateur. + </p> + <p> + Cut the cloth into strips a little over 4 feet in length. As you have 20 + feet in width to cover, and the cloth is one yard wide, you will need + seven strips for each plane, so as to allow for laps, etc. This will give + you fourteen strips. Glue the end of each strip around the front + horizontal beams of the planes, and draw each strip back, over the ribs, + tacking the edges to the ribs as you go along, with small copper or brass + tacks. In doing this keep the cloth smooth and stretched tight. Tacks + should also be used in addition to the glue, to hold the cloth to the + horizontal beams. + </p> + <p> + Next, give the cloth a coat of varnish on the clear, or upper side, and + when this is dry your glider will be ready for use. + </p> + <p> + Reinforcing the Cloth. + </p> + <p> + While not absolutely necessary for amateur purposes, reinforcement of the + cloth, so as to avoid any tendency to split or tear out from + wind-pressure, is desirable. One way of doing this is to tack narrow + strips of some heavier material, like felt, over the cloth where it laps + on the ribs. Another is to sew slips or pockets in the cloth itself and + let the ribs run through them. Still another method is to sew 2-inch + strips (of the same material as the cover) on the cloth, placing them + about one yard apart, but having them come in the center of each piece of + covering, and not on the laps where the various pieces are joined. + </p> + <p> + Use of Armpieces. + </p> + <p> + Should armpieces be desired, aside from those afforded by the center + struts, take two pieces of spruce, 3 feet long, by 1 x 1 3/4 inches, and + bolt them to the front and rear beams of the lower plane about 14 inches + apart. These will be more comfortable than using the struts, as the + operator will not have to spread his arms so much. In using the struts the + operator, as a rule, takes hold of them with his hands, while with the + armpieces, as the name implies, he places his arms over them, one of the + strips coming under each armpit. + </p> + <p> + Frequently somebody asks why the ribs should be curved. The answer is + easy. The curvature tends to direct the air downward toward the rear and, + as the air is thus forced downward, there is more or less of an impact + which assists in propelling the aeroplane upwards. + </p> + <p> + <a name="link2HCH0006" id="link2HCH0006"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER VI. LEARNING TO FLY. + </h2> + <p> + Don't be too ambitious at the start. Go slow, and avoid unnecessary risks. + At its best there is an element of danger in aviation which cannot be + entirely eliminated, but it may be greatly reduced and minimized by the + use of common sense. + </p> + <p> + Theoretically, the proper way to begin a glide is from the top of an + incline, facing against the wind, so that the machine will soar until the + attraction of gravitation draws it gradually to the ground. This is the + manner in which experienced aviators operate, but it must be kept in mind + that these men are experts. They understand air currents, know how to + control the action and direction of their machines by shifting the + position of their bodies, and by so doing avoid accidents which would be + unavoidable by a novice. + </p> + <p> + Begin on Level Ground. + </p> + <p> + Make your first flights on level ground, having a couple of men to assist + you in getting the apparatus under headway. Take your position in the + center rectangle, back far enough to give the forward edges of the glider + an inclination to tilt upward very slightly. Now start and run forward at + a moderately rapid gait, one man at each end of the glider assisting you. + As the glider cuts into the air the wind will catch under the uplifted + edges of the curved planes, and buoy it up so that it will rise in the air + and take you with it. This rise will not be great, just enough to keep you + well clear of the ground. Now project your legs a little to the front so + as to shift the center of gravity a trifle and bring the edges of the + glider on an exact level with the atmosphere. This, with the momentum + acquired in the start, will keep the machine moving forward for some + distance. + </p> + <p> + Effect of Body Movements. + </p> + <p> + When the weight of the body is slightly back of the center of gravity the + edges of the advancing planes are tilted slightly upward. The glider in + this position acts as a scoop, taking in the air which, in turn, lifts it + off the ground. When a certain altitude is reached—this varies with + the force of the wind—the tendency to a forward movement is lost and + the glider comes to the ground. It is to prolong the forward movement as + much as possible that the operator shifts the center of gravity slightly, + bringing the apparatus on an even keel as it were by lowering the + advancing edges. This done, so long as there is momentum enough to keep + the glider moving, it will remain afloat. + </p> + <p> + If you shift your body well forward it will bring the front edges of the + glider down, and elevate the rear ones. In this way the air will be + "spilled" out at the rear, and, having lost the air support or buoyancy, + the glider comes down to the ground. A few flights will make any ordinary + man proficient in the control of his apparatus by his body movements, not + only as concerns the elevating and depressing of the advancing edges, but + also actual steering. You will quickly learn, for instance, that, as the + shifting of the bodily weight backwards and forwards affects the upward + and downward trend of the planes, so a movement sideways—to the left + or the right—affects the direction in which the glider travels. + </p> + <p> + Ascends at an Angle. + </p> + <p> + In ascending, the glider and flying machine, like the bird, makes an + angular, not a vertical flight. Just what this angle of ascension may be + is difficult to determine. It is probable and in fact altogether likely, + that it varies with the force of the wind, weight of the rising body, + power of propulsion, etc. This, in the language of physicists, is the + angle of inclination, and, as a general thing, under normal conditions + (still air) should be put down as about one in ten, or 5 3/4 degrees. This + would be an ideal condition, but it has not, as vet been reached. The + force of the wind affects the angle considerably, as does also the weight + and velocity of the apparatus. In general practice the angle varies from + 23 to 45 degrees. At more than 45 degrees the supporting effort is + overcome by the resistance to forward motion. + </p> + <p> + Increasing the speed or propulsive force, tends to lessen the angle at + which the machine may be successfully operated because it reduces the wind + pressure. Most of the modern flying machines are operated at an angle of + 23 degrees, or less. + </p> + <p> + Maintaining an Equilibrium. + </p> + <p> + Stable equilibrium is one of the main essentials to successful flight, and + this cannot be preserved in an uncertain, gusty wind, especially by an + amateur. The novice should not attempt a glide unless the conditions are + just right. These conditions are: A clear, level space, without + obstructions, such as trees, etc., and a steady wind of not exceeding + twelve miles an hour. Always fly against the wind. + </p> + <p> + When a reasonable amount of proficiency in the handling of the machine on + level ground has been acquired the field of practice may be changed to + some gentle slope. In starting from a slope it will be found easier to + keep the machine afloat, but the experience at first is likely to be very + disconcerting to a man of less than iron nerve. As the glider sails away + from the top of the slope the distance between him and the ground + increases rapidly until the aviator thinks he is up a hundred miles in the + air. If he will keep cool, manipulate his apparatus so as to preserve its + equilibrium, and "let nature take its course," he will come down gradually + and safely to the ground at a considerable distance from the starting + place. This is one advantage of starting from an elevation—your + machine will go further. + </p> + <p> + But, if the aviator becomes "rattled"; if he loses control of his machine, + serious results, including a bad fall with risk of death, are almost + certain. And yet this practice is just as necessary as the initial lessons + on level ground. When judgment is used, and "haste made slowly," there is + very little real danger. While experimenting with gliders the Wrights made + flights innumerable under all sorts of conditions and never had an + accident of any kind. + </p> + <p> + Effects of Wind Currents. + </p> + <p> + The larger the machine the more difficult it will be to control its + movements in the air, and yet enlargement is absolutely necessary as + weight, in the form of motor, rudder, etc., is added. + </p> + <p> + Air currents near the surface of the ground are diverted by every + obstruction unless the wind is blowing hard enough to remove the + obstruction entirely. Take, for instance, the case of a tree or shrub, in + a moderate wind of from ten to twelve miles an hour. As the wind strikes + the tree it divides, part going to one side and part going to the other, + while still another part is directed upward and goes over the top of the + obstruction. This makes the handling of a glider on an obstructed field + difficult and uncertain. To handle a glider successfully the place of + operation should be clear and the wind moderate and steady. If it is gusty + postpone your flight. In this connection it will be well to understand the + velocity of the wind, and what it means as shown in the following table: + </p> +<pre xml:space="preserve"> + Miles per hour Feet per second Pressure per sq. foot + 10 14.7 .492 + 25 36.7 3.075 + 50 73.3 12.300 + 100 146.6 49.200 +</pre> + <p> + Pressure of wind increases in proportion to the square of the velocity. + Thus wind at 10 miles an hour has four times the pressure of wind at 5 + miles an hour. The greater this pressure the large and heavier the object + which can be raised. Any boy who has had experience in flying kites can + testify to this, High winds, however, are almost invariably gusty and + uncertain as to direction, and this makes them dangerous for aviators. It + is also a self-evident fact that, beyond a certain stage, the harder the + wind blows the more difficult it is to make headway against it. + </p> + <p> + Launching Device for Gliders. + </p> + <p> + On page 195 will be found a diagram of the various parts of a launcher for + gliders, designed and patented by Mr. Octave Chanute. In describing this + invention in Aeronautics, Mr. Chanute says: + </p> + <p> + "In practicing, the track, preferably portable, is generally laid in the + direction of the existing wind and the car, preferably a light + platform-car, is placed on the track. The truck carrying the winding-drum + and its motor is placed to windward a suitable distance—say from two + hundred to one thousand feet—and is firmly blocked or anchored in + line with the portable track, which is preferably 80 or 100 feet in + length. The flying or gliding machine to be launched with its operator is + placed on the platform-car at the leeward end of the portable track. The + line, which is preferably a flexible combination wire-and-cord cable, is + stretched between the winding-drum on the track and detachably secured to + the flying or gliding machine, preferably by means of a trip-hoop, or else + held in the hand of the operator, so that the operator may readily detach + the same from the flying-machine when the desired height is attained." + </p> + <p> + How Glider Is Started. + </p> + <p> + "Then upon a signal given by the operator the engineer at the motor puts + it into operation, gradually increasing the speed until the line is wound + upon the drum at a maximum speed of, say, thirty miles an hour. The + operator of the flying-machine, whether he stands upright and carries it + on his shoulders, or whether he sits or lies down prone upon it, adjusts + the aeroplane or carrying surfaces so that the wind shall strike them on + the top and press downward instead of upward until the platform-car under + action of the winding-drum and line attains the required speed. + </p> + <p> + "When the operator judges that his speed is sufficient, and this depends + upon the velocity of the wind as well as that of the car moving against + the wind, he quickly causes the front of the flying-machine to tip upward, + so that the relative wind striking on the under side of the planes or + carrying surfaces shall lift the flying machine into the air. It then + ascends like a kite to such height as may be desired by the operator, who + then trips the hook and releases the line from the machine." + </p> + <p> + What the Operator Does. + </p> + <p> + "The operator being now free in the air has a certain initial velocity + imparted by the winding-drum and line and also a potential energy + corresponding to his height above the ground. If the flying or gliding + machine is provided with a motor, he can utilize that in his further + flight, and if it is a simple gliding machine without motor he can make a + descending flight through the air to such distance as corresponds to the + velocity acquired and the height gained, steering meanwhile by the devices + provided for that purpose. + </p> + <p> + "The simplest operation or maneuver is to continue the flight straight + ahead against the wind; but it is possible to vary this course to the + right or left, or even to return in downward flight with the wind to the + vicinity of the starting-point. Upon nearing the ground the operator tips + upward his carrying-surfaces and stops his headway upon the cushion of + increased air resistance so caused. The operator is in no way permanently + fastened to his machine, and the machine and the operator simply rest upon + the light platform-car, so that the operator is free to rise with the + machine from the car whenever the required initial velocity is attained. + </p> + <p> + Motor For the Launcher. + </p> + <p> + "The motor may be of any suitable kind or construction, but is preferably + an electric or gasolene motor. The winding-drum is furnished with any + suitable or customary reversing-guide to cause the line to wind smoothly + and evenly upon the drum. The line is preferably a cable composed of + flexible wire and having a cotton or other cord core to increase its + flexibility. The line extends from the drum to the flying or gliding + machine. Its free end may, if desired, be grasped and held by the operator + until the flying-machine ascends to the desired height, when by simply + letting go of the line the operator may continue his flight free. The + line, however, is preferably connected to the flying or gliding machine + directly by a trip-hook having a handle or trip lever within reach of the + operator, so that when he ascends to the required height he may readily + detach the line from the flying or gliding machine." + </p> + <p> + <a name="link2HCH0007" id="link2HCH0007"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER VII. PUTTING ON THE RUDDER. + </h2> + <p> + Gliders as a rule have only one rudder, and this is in the rear. It tends + to keep the apparatus with its head to the wind. Unlike the rudder on a + boat it is fixed and immovable. The real motor-propelled flying machine, + generally has both front and rear rudders manipulated by wire cables at + the will of the operator. + </p> + <p> + Allowing that the amateur has become reasonably expert in the manipulation + of the glider he should, before constructing an actual flying machine, + equip his glider with a rudder. + </p> + <p> + Cross Pieces for Rudder Beam. + </p> + <p> + To do this he should begin by putting in a cross piece, 2 feet long by 1/4 + x 3/4 inches between the center struts, in the lower plane. This may be + fastened to the struts with bolts or braces. The former method is + preferable. On this cross piece, and on the rear frame of the plane + itself, the rudder beam is clamped and bolted. This rudder beam is 8 feet + 11 inches long. Having put these in place duplicate them in exactly the + same manner and dimensions from the upper frame The cross pieces on which + the ends of the rudder beams are clamped should be placed about one foot + in advance of the rear frame beam. + </p> + <p> + The Rudder Itself. + </p> + <p> + The next step is to construct the rudder itself. This consists of two + sections, one horizontal, the other vertical. The latter keeps the + aeroplane headed into the wind, while the former keeps it steady—preserves + the equilibrium. + </p> + <p> + The rudder beams form the top and bottom frames of the vertical rudder. To + these are bolted and clamped two upright pieces, 3 feet, 10 inches in + length, and 3/4 inch in cross section. These latter pieces are placed + about two feet apart. This completes the framework of the vertical rudder. + See next page (59). + </p> + <p> + For the horizontal rudder you will require two strips 6 feet long, and + four 2 feet long. Find the exact center of the upright pieces on the + vertical rudder, and at this spot fasten with bolts the long pieces of the + horizontal, placing them on the outside of the vertical strips. Next join + the ends of the horizontal strips with the 2-foot pieces, using small + screws and corner braces. This done you will have two of the 2-foot pieces + left. These go in the center of the horizontal frame, "straddling" the + vertical strips, as shown in the illustration. + </p> + <p> + The framework is to be covered with cloth in the same manner as the + planes. For this about ten yards will be needed. + </p> + <p> + Strengthening the Rudder. + </p> + <p> + To ensure rigidity the rudder must be stayed with guy wires. For this + purpose the No. 12 piano wire is the best. Begin by running two of these + wires from the top eye-bolts of stanchions 3 and 4, page 37, to rudder + beam where it joins the rudder planes, fastening them at the bottom. Then + run two wires from the top of the rudder beam at the same point, to the + bottom eye-bolts of the same stanchions. This will give you four diagonal + wires reaching from the rudder beam to the top and bottom planes of the + glider. Now, from the outer ends of the rudder frame run four similar + diagonal wires to the end of the rudder beam where it rests on the cross + piece. You will then have eight truss wires strengthening the connection + of the rudder to the main body of the glider. + </p> + <p> + The framework of the rudder planes is then to be braced in the same way, + which will take eight more wires, four for each rudder plane. All the + wires are to be connected at one end with turn-buckles so the tension may + be regulated as desired. + </p> + <p> + In forming the rudder frame it will be well to mortise the corners, tack + them together with small nails, and then put in a corner brace in the + inside of each joint. In doing this bear in mind that the material to be + thus fastened is light, and consequently the lightest of nails, screws, + bolts and corner pieces, etc., is necessary. + </p> + <p> + <a name="link2HCH0008" id="link2HCH0008"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER VIII. THE REAL FLYING MACHINE. + </h2> + <p> + We will now assume that you have become proficient enough to warrant an + attempt at the construction of a real flying machine—one that will + not only remain suspended in the air at the will of the operator, but make + respectable progress in whatever direction he may desire to go. The + glider, it must be remembered, is not steerable, except to a limited + extent, and moves only in one direction—against the wind. Besides + this its power of flotation—suspension in the air—is + circumscribed. + </p> + <p> + Larger Surface Area Required. + </p> + <p> + The real flying machine is the glider enlarged, and equipped with motor + and propeller. The first thing to do is to decide upon the size required. + While a glider of 20 foot spread is large enough to sustain a man it could + not under any possible conditions, be made to rise with the weight of the + motor, propeller and similar equipment added. As the load is increased so + must the surface area of the planes be increased. Just what this increase + in surface area should be is problematical as experienced aviators + disagree, but as a general proposition it may be placed at from three to + four times the area of a 20-foot glider. <a href="#linknote-3" + name="linknoteref-3" id="linknoteref-3"><small>3</small></a> + </p> + <p> + Some Practical Examples. + </p> + <p> + The Wrights used a biplane 41 feet in spread, and 6 1/2 ft. deep. This, + for the two planes, gives a total surface area of 538 square feet, + inclusive of auxiliary planes. This sustains the engine equipment, + operator, etc., a total weight officially announced at 1,070 pounds. It + shows a lifting capacity of about two pounds to the square foot of plane + surface, as against a lifting capacity of about 1/2 pound per square foot + of plane surface for the 20-foot glider. This same Wright machine is also + reported to have made a successful flight, carrying a total load of 1,100 + pounds, which would be over two pounds for each square foot of surface + area, which, with auxiliary planes, is 538 square feet. + </p> + <p> + To attain the same results in a monoplane, the single surface would have + to be 60 feet in spread and 9 feet deep. But, while this is the + mathematical rule, Bleriot has demonstrated that it does not always hold + good. On his record-breaking trip across the English channel, July 25th, + 1909, the Frenchman was carried in a monoplane 24 1/2 feet in spread, and + with a total sustaining surface of 150 1/2 square feet. The total weight + of the outfit, including machine, operator and fuel sufficient for a + three-hour run, was only 660 pounds. With an engine of (nominally) 25 + horsepower the distance of 21 miles was covered in 37 minutes. + </p> + <p> + Which is the Best? + </p> + <p> + Right here an established mathematical quantity is involved. A small plane + surface offers less resistance to the air than a large one and + consequently can attain a higher rate of speed. As explained further on in + this chapter speed is an important factor in the matter of + weight-sustaining capacity. A machine that travels one-third faster than + another can get along with one-half the surface area of the latter without + affecting the load. See the closing paragraph of this chapter on this + point. In theory the construction is also the simplest, but this is not + always found to be so in practice. The designing and carrying into + execution of plans for an extensive area like that of a monoplane involves + great skill and cleverness in getting a framework that will be strong + enough to furnish the requisite support without an undue excess of weight. + This proposition is greatly simplified in the biplane and, while the speed + attained by the latter may not be quite so great as that of the monoplane, + it has much larger weight-carrying capacity. + </p> + <p> + Proper Sizes For Frame. + </p> + <p> + Allowing that the biplane form is selected the construction may be + practically identical with that of the 20-foot glider described in Chapter + V., except as to size and elimination of the armpieces. In size the + surface planes should be about twice as large as those of the 20-foot + glider, viz: 40 feet spread instead of 20, and 6 feet deep instead of 3. + The horizontal beams, struts, stanchions, ribs, etc., should also be + increased in size proportionately. + </p> + <p> + While care in the selection of clear, straight-grained timber is important + in the glider, it is still more important in the construction of a + motor-equipped flying machine as the strain on the various parts will be + much greater. + </p> + <p> + How to Splice Timbers. + </p> + <p> + It is practically certain that you will have to resort to splicing the + horizontal beams as it will be difficult, if not impossible, to find + 40-foot pieces of timber totally free from knots and worm holes, and of + straight grain. + </p> + <p> + If splicing is necessary select two good 20-foot pieces, 3 inches wide and + 1 1/2 inches thick, and one 10-foot long, of the same thickness and width. + Plane off the bottom sides of the 10-foot strip, beginning about two feet + back from each end, and taper them so the strip will be about 3/4 inch + thick at the extreme ends. Lay the two 20-foot beams end to end, and under + the joint thus made place the 10-foot strip, with the planed-off ends + downward. The joint of the 20-foot pieces should be directly in the center + of the 10-foot piece. Bore ten holes (with a 1/4-inch augur) equi-distant + apart through the 20-foot strips and the 10-foot strip under them. Through + these holes run 1/4-inch stove bolts with round, beveled heads. In placing + these bolts use washers top and bottom, one between the head and the top + beam, and the other between the bottom beam and the screw nut which holds + the bolt. Screw the nuts down hard so as to bring the two beams tightly + together, and you will have a rigid 40-foot beam. + </p> + <p> + Splicing with Metal Sleeves. + </p> + <p> + An even better way of making a splice is by tonguing and grooving the ends + of the frame pieces and enclosing them in a metal sleeve, but it requires + more mechanical skill than the method first named. The operation of + tonguing and grooving is especially delicate and calls for extreme nicety + of touch in the handling of tools, but if this dexterity is possessed the + job will be much more satisfactory than one done with a third timber. + </p> + <p> + As the frame pieces are generally about 1 1/2 inch in diameter, the tongue + and the groove into which the tongue fits must be correspondingly small. + Begin by sawing into one side of one of the frame pieces about 4 inches + back from the end. Make the cut about 1/2 inch deep. Then turn the piece + over and duplicate the cut. Next saw down from the end to these cuts. When + the sawed-out parts are removed you will have a "tongue" in the end of the + frame timber 4 inches long and 1/2 inch thick. The next move is to saw out + a 5/8-inch groove in the end of the frame piece which is to be joined. You + will have to use a small chisel to remove the 5/8-inch bit. This will + leave a groove into which the tongue will fit easily. + </p> + <p> + Joining the Two Pieces. + </p> + <p> + Take a thin metal sleeve—this is merely a hollow tube of aluminum or + brass open at each end—8 inches long, and slip it over either the + tongued or grooved end of one of the frame timbers. It is well to have the + sleeve fit snugly, and this may necessitate a sand-papering of the frame + pieces so the sleeve will slip on. + </p> + <p> + Push the sleeve well back out of the way. Cover the tongue thoroughly with + glue, and also put some on the inside of the groove. Use plenty of glue. + Now press the tongue into the groove, and keep the ends firmly together + until the glue is thoroughly dried. Rub off the joint lightly with + sand-paper to remove any of the glue which may have oozed out, and slip + the sleeve into place over the joint. Tack the sleeve in position with + small copper tacks, and you will have an ideal splice. + </p> + <p> + The same operation is to be repeated on each of the four frame pieces. Two + 20-foot pieces joined in this way will give a substantial frame, but when + suitable timber of this kind can not be had, three pieces, each 6 feet 11 + inches long, may be used. This would give 20 feet 9 inches, of which 8 + inches will be taken up in the two joints, leaving the frame 20 feet 1 + inch long. + </p> + <p> + Installation of Motor. + </p> + <p> + Next comes the installation of the motor. The kinds and efficiency of the + various types are described in the following chapter (IX). All we are + interested in at this point is the manner of installation. This varies + according to the personal ideas of the aviator. Thus one man puts his + motor in the front of his machine, another places it in the center, and + still another finds the rear of the frame the best. All get good results, + the comparative advantages of which it is difficult to estimate. Where one + man, as already explained, flies faster than another, the one beaten from + the speed standpoint has an advantage in the matter of carrying weight, + etc. + </p> + <p> + The ideas of various well-known aviators as to the correct placing of + motors may be had from the following: + </p> + <p> + Wrights—In rear of machine and to one side. + </p> + <p> + Curtiss—Well to rear, about midway between upper and lower planes. + </p> + <p> + Raich—In rear, above the center. + </p> + <p> + Brauner-Smith—In exact center of machine. + </p> + <p> + Van Anden—In center. + </p> + <p> + Herring-Burgess—Directly behind operator. + </p> + <p> + Voisin—In rear, and on lower plane. + </p> + <p> + Bleriot—In front. + </p> + <p> + R. E. P.—In front. + </p> + <p> + The One Chief Object. + </p> + <p> + An even distribution of the load so as to assist in maintaining the + equilibrium of the machine, should be the one chief object in deciding + upon the location of the motor. It matters little what particular spot is + selected so long as the weight does not tend to overbalance the machine, + or to "throw it off an even keel." It is just like loading a vessel, an + operation in which the expert seeks to so distribute the weight of the + cargo as to keep the vessel in a perfectly upright position, and prevent a + "list" or leaning to one side. The more evenly the cargo is distributed + the more perfect will be the equilibrium of the vessel and the better it + can be handled. Sometimes, when not properly stowed, the cargo shifts, and + this at once affects the position of the craft. When a ship "lists" to + starboard or port a preponderating weight of the cargo has shifted + sideways; if bow or stern is unduly depressed it is a sure indication that + the cargo has shifted accordingly. In either event the handling of the + craft becomes not only difficult, but extremely hazardous. Exactly the + same conditions prevail in the handling of a flying machine. + </p> + <p> + Shape of Machine a Factor. + </p> + <p> + In placing the motor you must be governed largely by the shape and + construction of the flying machine frame. If the bulk of the weight of the + machine and auxiliaries is toward the rear, then the natural location for + the motor will be well to the front so as to counterbalance the excess in + rear weight. In the same way if the preponderance of the weight is + forward, then the motor should be placed back of the center. + </p> + <p> + As the propeller blade is really an integral part of the motor, the latter + being useless without it, its placing naturally depends upon the location + selected for the motor. + </p> + <p> + Rudders and Auxiliary Planes. + </p> + <p> + Here again there is great diversity of opinion among aviators as to size, + location and form. The striking difference of ideas in this respect is + well illustrated in the choice made by prominent makers as follows: + </p> + <p> + Voisin—horizontal rudder, with two wing-like planes, in front; + box-like longitudinal stability plane in rear, inside of which is a + vertical rudder. + </p> + <p> + Wright—large biplane horizontal rudder in front at considerable + distance—about 10 feet—from the main planes; vertical biplane + rudder in rear; ends of upper and lower main planes made flexible so they + may be moved. + </p> + <p> + Curtiss—horizontal biplane rudder, with vertical damping plane + between the rudder planes about 10 feet in front of main planes; vertical + rudder in rear; stabilizing planes at each end of upper main plane. + </p> + <p> + Bleriot—V-shaped stabilizing fin, projecting from rear of plane, + with broad end outward; to the broad end of this fin is hinged a vertical + rudder; horizontal biplane rudder, also in rear, under the fin. + </p> + <p> + These instances show forcefully the wide diversity of opinion existing + among experienced aviators as to the best manner of placing the rudders + and stabilizing, or auxiliary planes, and make manifest how hopeless would + be the task of attempting to select any one form and advise its exclusive + use. + </p> + <p> + Rudder and Auxiliary Construction. + </p> + <p> + The material used in the construction of the rudders and auxiliary planes + is the same as that used in the main planes—spruce for the framework + and some kind of rubberized or varnished cloth for the covering. The + frames are joined and wired in exactly the same manner as the frames of + the main planes, the purpose being to secure the same strength and + rigidity. Dimensions of the various parts depend upon the plan adopted and + the size of the main plane. + </p> + <p> + No details as to exact dimensions of these rudders and auxiliary planes + are obtainable. The various builders, while willing enough to supply data + as to the general measurements, weight, power, etc., of their machines, + appear to have overlooked the details of the auxiliary parts, thinking, + perhaps, that these were of no particular import to the general public. In + the Wright machine, the rear horizontal and front vertical rudders may be + set down as being about one-quarter (probably a little less) the size of + the main supporting planes. + </p> + <p> + Arrangement of Alighting Gear. + </p> + <p> + Most modern machines are equipped with an alighting gear, which not only + serves to protect the machine and aviator from shock or injury in touching + the ground, but also aids in getting under headway. All the leading makes, + with the exception of the Wright, are furnished with a frame carrying from + two to five pneumatic rubber-tired bicycle wheels. In the Curtiss and + Voisin machines one wheel is placed in front and two in the rear. In the + Bleriot and other prominent machines the reverse is the rule—two + wheels in front and one in the rear. Farman makes use of five wheels, one + in the extreme rear, and four, arranged in pairs, a little to the front of + the center of the main lower plane. + </p> + <p> + In place of wheels the Wright machine is equipped with a skid-like device + consisting of two long beams attached to the lower plane by stanchions and + curving up far in front, so as to act as supports to the horizontal + rudder. + </p> + <p> + Why Wood Is Favored. + </p> + <p> + A frequently asked question is: "Why is not aluminum, or some similar + metal, substituted for wood." Wood, particularly spruce, is preferred + because, weight considered, it is much stronger than aluminum, and this is + the lightest of all metals. In this connection the following table will be + of interest: + </p> +<pre xml:space="preserve"> + Compressive + Weight Tensile Strength Strength + per cubic foot per sq. inch per sq. inch + Material in lbs. in lbs. in lbs. + Spruce.... 25 8,000 5,000 + Aluminum 162 16,000 ...... + Brass (sheet) 510 23,000 12,000 + Steel (tool) 490 100,000 40,000 + Copper (sheet) 548 30,000 40,000 +</pre> + <p> + As extreme lightness, combined with strength, especially tensile strength, + is the great essential in flying-machine construction, it can be readily + seen that the use of metal, even aluminum, for the framework, is + prohibited by its weight. While aluminum has double the strength of spruce + wood it is vastly heavier, and thus the advantage it has in strength is + overbalanced many times by its weight. The specific gravity of aluminum is + 2.50; that of spruce is only 0.403. + </p> + <p> + Things to Be Considered. + </p> + <p> + In laying out plans for a flying machine there are five important points + which should be settled upon before the actual work of construction is + started. These are: + </p> + <p> + First—Approximate weight of the machine when finished and equipped. + </p> + <p> + Second—Area of the supporting surface required. + </p> + <p> + Third—Amount of power that will be necessary to secure the desired + speed and lifting capacity. + </p> + <p> + Fourth—Exact dimensions of the main framework and of the auxiliary + parts. + </p> + <p> + Fifth—Size, speed and character of the propeller. + </p> + <p> + In deciding upon these it will be well to take into consideration the + experience of expert aviators regarding these features as given elsewhere. + (See Chapter X.) + </p> + <p> + Estimating the Weights Involved. + </p> + <p> + In fixing upon the probable approximate weight in advance of construction + much, of course, must be assumed. This means that it will be a matter of + advance estimating. If a two-passenger machine is to be built we will + start by assuming the maximum combined weight of the two people to be 350 + pounds. Most of the professional aviators are lighter than this. Taking + the medium between the weights of the Curtiss and Wright machines we have + a net average of 850 pounds for the framework, motor, propeller, etc. + This, with the two passengers, amounts to 1,190 pounds. As the machines + quoted are in successful operation it will be reasonable to assume that + this will be a safe basis to operate on. + </p> + <p> + What the Novice Must Avoid. + </p> + <p> + This does not mean, however, that it will be safe to follow these weights + exactly in construction, but that they will serve merely as a basis to + start from. Because an expert can turn out a machine, thoroughly equipped, + of 850 pounds weight, it does not follow that a novice can do the same + thing. The expert's work is the result of years of experience, and he has + learned how to construct frames and motor plants of the utmost lightness + and strength. + </p> + <p> + It will be safer for the novice to assume that he can not duplicate the + work of such men as Wright and Curtiss without adding materially to the + gross weight of the framework and equipment minus passengers. + </p> + <p> + How to Distribute the Weight. + </p> + <p> + Let us take 1,030 pounds as the net weight of the machine as against the + same average in the Wright and Curtiss machines. Now comes the question of + distributing this weight between the framework, motor, and other + equipment. As a general proposition the framework should weigh about twice + as much as the complete power plant (this is for amateur work). + </p> + <p> + The word "framework" indicates not only the wooden frames of the main + planes, auxiliary planes, rudders, etc., but the cloth coverings as well—everything + in fact except the engine and propeller. + </p> + <p> + On the basis named the framework would weigh 686 pounds, and the power + plant 344. These figures are liberal, and the results desired may be + obtained well within them as the novice will learn as he makes progress in + the work. + </p> + <p> + Figuring on Surface Area. + </p> + <p> + It was Prof. Langley who first brought into prominence in connection with + flying machine construction the mathematical principle that the larger the + object the smaller may be the relative area of support. As explained in + Chapter XIII, there are mechanical limits as to size which it is not + practical to exceed, but the main principle remains in effect. + </p> + <p> + Take two aeroplanes of marked difference in area of surface. The larger + will, as a rule, sustain a greater weight in relative proportion to its + area than the smaller one, and do the work with less relative horsepower. + As a general thing well-constructed machines will average a supporting + capacity of one pound for every one-half square foot of surface area. + Accepting this as a working rule we find that to sustain a weight of 1,200 + pounds—machine and two passengers—we should have 600 square + feet of surface. + </p> + <p> + Distributing the Surface Area. + </p> + <p> + The largest surfaces now in use are those of the Wright, Voisin and + Antoinette machines—538 square feet in each. The actual sustaining + power of these machines, so far as known, has never been tested to the + limit; it is probable that the maximum is considerably in excess of what + they have been called upon to show. In actual practice the average is a + little over one pound for each one-half square foot of surface area. + </p> + <p> + Allowing that 600 square feet of surface will be used, the next question + is how to distribute it to the best advantage. This is another important + matter in which individual preference must rule. We have seen how the + professionals disagree on this point, some using auxiliary planes of large + size, and others depending upon smaller auxiliaries with an increase in + number so as to secure on a different plan virtually the same amount of + surface. + </p> + <p> + In deciding upon this feature the best thing to do is to follow the plans + of some successful aviator, increasing the area of the auxiliaries in + proportion to the increase in the area of the main planes. Thus, if you + use 600 square feet of surface where the man whose plans you are following + uses 500, it is simply a matter of making your planes one-fifth larger all + around. + </p> + <p> + The Cost of Production. + </p> + <p> + Cost of production will be of interest to the amateur who essays to + construct a flying machine. Assuming that the size decided upon is double + that of the glider the material for the framework, timber, cloth, wire, + etc., will cost a little more than double. This is because it must be + heavier in proportion to the increased size of the framework, and heavy + material brings a larger price than the lighter goods. If we allow $20 as + the cost of the glider material it will be safe to put down the cost of + that required for a real flying machine framework at $60, provided the + owner builds it himself. + </p> + <p> + As regards the cost of motor and similar equipment it can only be said + that this depends upon the selection made. There are some reliable + aviation motors which may be had as low as $500, and there are others + which cost as much as $2,000. + </p> + <p> + Services of Expert Necessary. + </p> + <p> + No matter what kind of a motor may be selected the services of an expert + will be necessary in its proper installation unless the amateur has + considerable genius in this line himself. As a general thing $25 should be + a liberal allowance for this work. No matter how carefully the engine may + be placed and connected it will be largely a matter of luck if it is + installed in exactly the proper manner at the first attempt. The chances + are that several alterations, prompted by the results of trials, will have + to be made. If this is the case the expert's bill may readily run up to + $50. If the amateur is competent to do this part of the work the entire + item of $50 may, of course, be cut out. + </p> + <p> + As a general proposition a fairly satisfactory flying machine, one that + will actually fly and carry the operator with it, may be constructed for + $750, but it will lack the better qualities which mark the higher priced + machines. This computation is made on the basis of $60 for material, $50 + for services of expert, $600 for motor, etc., and an allowance of $40 for + extras. + </p> + <p> + No man who has the flying machine germ in his system will be long + satisfied with his first moderate price machine, no matter how well it may + work. It's the old story of the automobile "bug" over again. The man who + starts in with a modest $1,000 automobile invariably progresses by easy + stages to the $4,000 or $5,000 class. The natural tendency is to want the + biggest and best attainable within the financial reach of the owner. + </p> + <p> + It's exactly the same way with the flying machine convert. The more + proficient he becomes in the manipulation of his car, the stronger becomes + the desire to fly further and stay in the air longer than the rest of his + brethren. This necessitates larger, more powerful, and more expensive + machines as the work of the germ progresses. + </p> + <p> + Speed Affects Weight Capacity. + </p> + <p> + Don't overlook the fact that the greater speed you can attain the smaller + will be the surface area you can get along with. If a machine with 500 + square feet of sustaining surface, traveling at a speed of 40 miles an + hour, will carry a weight of 1,200 pounds, we can cut the sustaining + surface in half and get along with 250 square feet, provided a speed of 60 + miles an hour can be obtained. At 100 miles an hour only 80 square feet of + surface area would be required. In both instances the weight sustaining + capacity will remain the same as with the 500 square feet of surface area—1,200 + pounds. + </p> + <p> + One of these days some mathematical genius will figure out this problem + with exactitude and we will have a dependable table giving the maximum + carrying capacity of various surface areas at various stated speeds, based + on the dimensions of the advancing edges. At present it is largely a + matter of guesswork so far as making accurate computation goes. Much + depends upon the shape of the machine, and the amount of surface offering + resistance to the wind, etc. + </p> + <p> + <a name="link2HCH0009" id="link2HCH0009"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER IX. SELECTION OF THE MOTOR. + </h2> + <p> + Motors for flying machines must be light in weight, of great strength, + productive of extreme speed, and positively dependable in action. It + matters little as to the particular form, or whether air or water cooled, + so long as the four features named are secured. There are at least a dozen + such motors or engines now in use. All are of the gasolene type, and all + possess in greater or lesser degree the desired qualities. Some of these + motors are: + </p> + <p> + Renault—8-cylinder, air-cooled; 50 horse power; weight 374 pounds. + </p> + <p> + Fiat—8-cylinder, air-cooled; 50 horse power; weight 150 pounds. + </p> + <p> + Farcot—8-cylinder, air-cooled; from 30 to 100 horse power, according + to bore of cylinders; weight of smallest, 84 pounds. + </p> + <p> + R. E. P.—10-cylinder, air-cooled; 150 horse power; weight 215 + pounds. + </p> + <p> + Gnome—7 and 14 cylinders, revolving type, air-cooled; 50 and 100 + horse power; weight 150 and 300 pounds. + </p> + <p> + Darracq—2 to 14 cylinders, water cooled; 30 to 200 horse power; + weight of smallest 100 pounds. + </p> + <p> + Wright—4-cylinder, water-cooled; 25 horse power; weight 200 pounds. + </p> + <p> + Antoinette—8 and 16-cylinder, water-cooled; 50 and 100 horse power; + weight 250 and 500 pounds. + </p> + <p> + E. N. V.—8-cylinder, water-cooled; from 30 to 80 horse power, + according to bore of cylinder; weight 150 to 400 pounds. + </p> + <p> + Curtiss—8-cylinder, water-cooled; 60 horse power; weight 300 pounds. + </p> + <p> + Average Weight Per Horse Power. + </p> + <p> + It will be noticed that the Gnome motor is unusually light, being about + three pounds to the horse power produced, as opposed to an average of 4 + 1/2 pounds per horse power in other makes. This result is secured by the + elimination of the fly-wheel, the engine itself revolving, thus obtaining + the same effect that would be produced by a fly-wheel. The Farcot is even + lighter, being considerably less than three pounds per horse power, which + is the nearest approach to the long-sought engine equipment that will make + possible a complete flying machine the total weight of which will not + exceed one pound per square foot of area. + </p> + <p> + How Lightness Is Secured. + </p> + <p> + Thus far foreign manufacturers are ahead of Americans in the production of + light-weight aerial motors, as is evidenced by the Gnome and Farcot + engines, both of which are of French make. Extreme lightness is made + possible by the use of fine, specially prepared steel for the cylinders, + thus permitting them to be much thinner than if ordinary forms of steel + were used. Another big saving in weight is made by substituting what are + known as "auto lubricating" alloys for bearings. These alloys are made of + a combination of aluminum and magnesium. + </p> + <p> + Still further gains are made in the use of alloy steel tubing instead of + solid rods, and also by the paring away of material wherever it can be + done without sacrificing strength. This plan, with the exclusive use of + the best grades of steel, regardless of cost, makes possible a marked + reduction in weight. + </p> + <p> + Multiplicity of Cylinders. + </p> + <p> + Strange as it may seem, multiplicity of cylinders does not always add + proportionate weight. Because a 4-cylinder motor weighs say 100 pounds, it + does not necessarily follow that an 8-cylinder equipment will weigh 200 + pounds. The reason of this will be plain when it is understood that many + of the parts essential to a 4-cylinder motor will fill the requirements of + an 8-cylinder motor without enlargement or addition. + </p> + <p> + Neither does multiplying the cylinders always increase the horsepower + proportionately. If a 4-cylinder motor is rated at 25 horsepower it is not + safe to take it for granted that double the number of cylinders will give + 50 horsepower. Generally speaking, eight cylinders, the bore, stroke and + speed being the same, will give double the power that can be obtained from + four, but this does not always hold good. Just why this exception should + occur is not explainable by any accepted rule. + </p> + <p> + Horse Power and Speed. + </p> + <p> + Speed is an important requisite in a flying-machine motor, as the velocity + of the aeroplane is a vital factor in flotation. At first thought, the + propeller and similar adjuncts being equal, the inexperienced mind would + naturally argue that a 50-horsepower engine should produce just double the + speed of one of 25-horsepower. That this is a fallacy is shown by actual + performances. The Wrights, using a 25-horsepower motor, have made 44 miles + an hour, while Bleriot, with a 50-horsepower motor, has a record of a + short-distance flight at the rate of 52 miles an hour. The fact is that, + so far as speed is concerned, much depends upon the velocity of the wind, + the size and shape of the aeroplane itself, and the size, shape and + gearing of the propeller. The stronger the wind is blowing the easier it + will be for the aeroplane to ascend, but at the same time the more + difficult it will be to make headway against the wind in a horizontal + direction. With a strong head wind, and proper engine force, your machine + will progress to a certain extent, but it will be at an angle. If the + aviator desired to keep on going upward this would be all right, but there + is a limit to the altitude which it is desirable to reach—from 100 + to 500 feet for experts—and after that it becomes a question of + going straight ahead. + </p> + <p> + Great Waste of Power. + </p> + <p> + One thing is certain—even in the most efficient of modern aerial + motors there is a great loss of power between the two points of production + and effect. The Wright outfit, which is admittedly one of the most + effective in use, takes one horsepower of force for the raising and + propulsion of each 50 pounds of weight. This, for a 25-horsepower engine, + would give a maximum lifting capacity of 1250 pounds. It is doubtful if + any of the higher rated motors have greater efficiency. As an 8-cylinder + motor requires more fuel to operate than a 4-cylinder, it naturally + follows that it is more expensive to run than the smaller motor, and a + normal increase in capacity, taking actual performances as a criterion, is + lacking. In other words, what is the sense of using an 8-cylinder motor + when one of 4 cylinders is sufficient? + </p> + <p> + What the Propeller Does. + </p> + <p> + Much of the efficiency of the motor is due to the form and gearing of the + propeller. Here again, as in other vital parts of flying-machine + mechanism, we have a wide divergence of opinion as to the best form. A + fish makes progress through the water by using its fins and tail; a bird + makes its way through the air in a similar manner by the use of its wings + and tail. In both instances the motive power comes from the body of the + fish or bird. + </p> + <p> + In place of fins or wings the flying machine is equipped with a propeller, + the action of which is furnished by the engine. Fins and wings have been + tried, but they don't work. + </p> + <p> + While operating on the same general principle, aerial propellers are much + larger than those used on boats. This is because the boat propeller has a + denser, more substantial medium to work in (water), and consequently can + get a better "hold," and produce more propulsive force than one of the + same size revolving in the air. This necessitates the aerial propellers + being much larger than those employed for marine purposes. Up to this + point all aviators agree, but as to the best form most of them differ. + </p> + <p> + Kinds of Propellers Used. + </p> + <p> + One of the most simple is that used by Curtiss. It consists of two + pear-shaped blades of laminated wood, each blade being 5 inches wide at + its extreme point, tapering slightly to the shaft connection. These blades + are joined at the engine shaft, in a direct line. The propeller has a + pitch of 5 feet, and weighs, complete, less than 10 pounds. The length + from end to end of the two blades is 6 1/2 feet. + </p> + <p> + Wright uses two wooden propellers, in the rear of his biplane, revolving + in opposite directions. Each propeller is two-bladed. + </p> + <p> + Bleriot also uses a two-blade wooden propeller, but it is placed in front + of his machine. The blades are each about 3 1/2 feet long and have an + acute "twist." + </p> + <p> + Santos-Dumont uses a two-blade wooden propeller, strikingly similar to the + Bleriot. + </p> + <p> + On the Antoinette monoplane, with which good records have been made, the + propeller consists of two spoon-shaped pieces of metal, joined at the + engine shaft in front, and with the concave surfaces facing the machine. + </p> + <p> + The propeller on the Voisin biplane is also of metal, consisting of two + aluminum blades connected by a forged steel arm. + </p> + <p> + Maximum thrust, or stress—exercise of the greatest air-displacing + force—is the object sought. This, according to experts, is best + obtained with a large propeller diameter and reasonably low speed. The + diameter is the distance from end to end of the blades, which on the + largest propellers ranges from 6 to 8 feet. The larger the blade surface + the greater will be the volume of air displaced, and, following this, the + greater will be the impulse which forces the aeroplane ahead. In all + centrifugal motion there is more or less tendency to disintegration in the + form of "flying off" from the center, and the larger the revolving object + is the stronger is this tendency. This is illustrated in the many + instances in which big grindstones and fly-wheels have burst from being + revolved too fast. To have a propeller break apart in the air would + jeopardize the life of the aviator, and to guard against this it has been + found best to make its revolving action comparatively slow. Besides this + the slow motion (it is only comparatively slow) gives the atmosphere a + chance to refill the area disturbed by one propeller blade, and thus have + a new surface for the next blade to act upon. + </p> + <p> + Placing of the Motor. + </p> + <p> + As on other points, aviators differ widely in their ideas as to the proper + position for the motor. Wright locates his on the lower plane, midway + between the front and rear edges, but considerably to one side of the + exact center. He then counter-balances the engine weight by placing his + seat far enough away in the opposite direction to preserve the center of + gravity. This leaves a space in the center between the motor and the + operator in which a passenger may be carried without disturbing the + equilibrium. + </p> + <p> + Bleriot, on the contrary, has his motor directly in front and preserves + the center of gravity by taking his seat well back, this, with the weight + of the aeroplane, acting as a counter-balance. + </p> + <p> + On the Curtiss machine the motor is in the rear, the forward seat of the + operator, and weight of the horizontal rudder and damping plane in front + equalizing the engine weight. + </p> + <p> + No Perfect Motor as Yet. + </p> + <p> + Engine makers in the United States, England, France and Germany are all + seeking to produce an ideal motor for aviation purposes. Many of the + productions are highly creditable, but it may be truthfully said that none + of them quite fill the bill as regards a combination of the minimum of + weight with the maximum of reliable maintained power. They are all, in + some respects, improvements upon those previously in use, but the great + end sought for has not been fully attained. + </p> + <p> + One of the motors thus produced was made by the French firm of Darracq at + the suggestion of Santos Dumont, and on lines laid down by him. Santos + Dumont wanted a 2-cylinder horizontal motor capable of developing 30 + horsepower, and not exceeding 4 1/2 pounds per horsepower in weight. + </p> + <p> + There can be no question as to the ability and skill of the Darracq + people, or of their desire to produce a motor that would bring new credit + and prominence to the firm. Neither could anything radically wrong be + detected in the plans. But the motor, in at least one important + requirement, fell short of expectations. + </p> + <p> + It could not be depended upon to deliver an energy of 30 horsepower + continuously for any length of time. Its maximum power could be secured + only in "spurts." + </p> + <p> + This tends to show how hard it is to produce an ideal motor for aviation + purposes. Santos Dumont, of undoubted skill and experience as an aviator, + outlined definitely what he wanted; one of the greatest designers in the + business drew the plans, and the famous house of Darracq bent its best + energies to the production. But the desired end was not fully attained. + </p> + <p> + Features of Darracq Motor. + </p> + <p> + Horizontal motors were practically abandoned some time ago in favor of the + vertical type, but Santos Dumont had a logical reason for reverting to + them. He wanted to secure a lower center of gravity than would be possible + with a vertical engine. Theoretically his idea was correct as the + horizontal motor lies flat, and therefore offers less resistance to the + wind, but it did not work out as desired. + </p> + <p> + At the same time it must be admitted that this Darracq motor is a marvel + of ingenuity and exquisite workmanship. The two cylinders, having a bore + of 5 1-10 inches and a stroke of 4 7-10 inches, are machined out of a + solid bar of steel until their weight is only 8 4-5 pounds complete. The + head is separate, carrying the seatings for the inlet and exhaust valves, + is screwed onto the cylinder, and then welded in position. A copper + water-jacket is fitted, and it is in this condition that the weight of 8 + 4-5 pounds is obtained. + </p> + <p> + On long trips, especially in regions where gasolene is hard to get, the + weight of the fuel supply is an important feature in aviation. As a + natural consequence flying machine operators favor the motor of greatest + economy in gasolene consumption, provided it gives the necessary power. + </p> + <p> + An American inventor, Ramsey by name, is working on a motor which is said + to possess great possibilities in this line. Its distinctive features + include a connecting rod much shorter than usual, and a crank shaft + located the length of the crank from the central axis of the cylinder. + This has the effect of increasing the piston stroke, and also of + increasing the proportion of the crank circle during which effective + pressure is applied to the crank. + </p> + <p> + Making the connecting rod shorter and leaving the crank mechanism the same + would introduce excessive cylinder friction. This Ramsey overcomes by the + location of his crank shaft. The effect of the long piston stroke thus + secured, is to increase the expansion of the gases, which in turn + increases the power of the engine without increasing the amount of fuel + used. + </p> + <p> + Propeller Thrust Important. + </p> + <p> + There is one great principle in flying machine propulsion which must not + be overlooked. No matter how powerful the engine may be unless the + propeller thrust more than overcomes the wind pressure there can be no + progress forward. Should the force of this propeller thrust and that of + the wind pressure be equal the result is obvious. The machine is at a + stand-still so far as forward progress is concerned and is deprived of the + essential advancing movement. + </p> + <p> + Speed not only furnishes sustentation for the airship, but adds to the + stability of the machine. An aeroplane which may be jerky and uncertain in + its movements, so far as equilibrium is concerned, when moving at a slow + gait, will readily maintain an even keel when the speed is increased. + </p> + <p> + Designs for Propeller Blades. + </p> + <p> + It is the object of all men who design propellers to obtain the maximum of + thrust with the minimum expenditure of engine energy. With this purpose in + view many peculiar forms of propeller blades have been evolved. In theory + it would seem that the best effects could be secured with blades so shaped + as to present a thin (or cutting) edge when they come out of the wind, and + then at the climax of displacement afford a maximum of surface so as to + displace as much air as possible. While this is the form most generally + favored there are others in successful operation. + </p> + <p> + There is also wide difference in opinion as to the equipment of the + propeller shaft with two or more blades. Some aviators use two and some + four. All have more or less success. As a mathematical proposition it + would seem that four blades should give more propulsive force than two, + but here again comes in one of the puzzles of aviation, as this result is + not always obtained. + </p> + <p> + Difference in Propeller Efficiency. + </p> + <p> + That there is a great difference in propeller efficiency is made readily + apparent by the comparison of effects produced in two leading makes of + machines—the Wright and the Voisin. + </p> + <p> + In the former a weight of from 1,100 to 1,200 pounds is sustained and + advance progress made at the rate of 40 miles an hour and more, with half + the engine speed of a 25 horse-power motor. This would be a sustaining + capacity of 48 pounds per horsepower. But the actual capacity of the + Wright machine, as already stated, is 50 pounds per horsepower. + </p> + <p> + The Voisin machine, with aviator, weighs about 1,370 pounds, and is + operated with a so-horsepower motor. Allowing it the same speed as the + Wright we find that, with double the engine energy, the lifting capacity + is only 27 1/2 pounds per horsepower. To what shall we charge this + remarkable difference? The surface of the planes is exactly the same in + both machines so there is no advantage in the matter of supporting area. + </p> + <p> + Comparison of Two Designs. + </p> + <p> + On the Wright machine two wooden propellers of two blades each (each blade + having a decided "twist") are used. As one 25 horsepower motor drives both + propellers the engine energy amounts to just one-half of this for each, or + 12 1/2 horsepower. And this energy is utilized at one-half the normal + engine speed. + </p> + <p> + On the Voisin a radically different system is employed. Here we have one + metal two-bladed propeller with a very slight "twist" to the blade + surfaces. The full energy of a 50-horsepower motor is utilized. + </p> + <p> + Experts Fail to Agree. + </p> + <p> + Why should there be such a marked difference in the results obtained? Who + knows? Some experts maintain that it is because there are two propellers + on the Wright machine and only one on the Voisin, and consequently double + the propulsive power is exerted. But this is not a fair deduction, unless + both propellers are of the same size. Propulsive power depends upon the + amount of air displaced, and the energy put into the thrust which + displaces the air. + </p> + <p> + Other experts argue that the difference in results may be traced to the + difference in blade design, especially in the matter of "twist." + </p> + <p> + The fact is that propeller results depend largely upon the nature of the + aeroplanes on which they are used. A propeller, for instance, which gives + excellent results on one type of aeroplane, will not work satisfactorily + on another. + </p> + <p> + There are some features, however, which may be safely adopted in propeller + selection. These are: As extensive a diameter as possible; blade area 10 + to 15 per cent of the area swept; pitch four-fifths of the diameter; + rotation slow. The maximum of thrust effort will be thus obtained. + </p> + <p> + <a name="link2HCH0010" id="link2HCH0010"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER X. PROPER DIMENSIONS OF MACHINES. + </h2> + <p> + In laying out plans for a flying machine the first thing to decide upon is + the size of the plane surfaces. The proportions of these must be based + upon the load to be carried. This includes the total weight of the machine + and equipment, and also the operator. This will be a rather difficult + problem to figure out exactly, but practical approximate figures may be + reached. + </p> + <p> + It is easy to get at the weight of the operator, motor and propeller, but + the matter of determining, before they are constructed, what the planes, + rudders, auxiliaries, etc., will weigh when completed is an intricate + proposition. The best way is to take the dimensions of some successful + machine and use them, making such alterations in a minor way as you may + desire. + </p> + <p> + Dimensions of Leading Machines. + </p> + <p> + In the following tables will be found the details as to surface area, + weight, power, etc., of the nine principal types of flying machines which + are now prominently before the public: + </p> +<pre xml:space="preserve"> + MONOPLANES. + Surface area Spread in Depth in + Make Passengers sq. feet linear feet linear + feet + Santos-Dumont.. 1 110 16.0 26.0 + Bleriot..... 1 150.6 24.6 22.0 + R. E. P..... 1 215 34.1 28.9 + Bleriot..... 2 236 32.9 23.0 + Antoinette.... 2 538 41.2 37.9 + No. of Weight Without + Propeller + Make Cylinders Horse Power Operator + Diameter + Santos-Dumont.. 2 30 250 5.0 + Bleriot..... 3 25 680 6.9 + R. E. P..... 7 35 900 6.6 + Bleriot..... 7 50 1,240 8.1 + Antoinette... 8 50 1,040 7.2 + + BIPLANES. + Surface Area Spread in Depth + in + Make Passengers sq. feet linear feet linear + feet + Curtiss... 2 258 29.0 + 28.7 + Wright.... 2 538 41.0 + 30.7 + Farman.... 2 430 32.9 + 39.6 + Voisin.... 2 538 37.9 + 39.6 + + No. of Weight Without + Propeller + Make Cylinders Horse Power Operator + Diameter + Curtiss... 8 50 600 6.0 + Wright.... 4 25 1,100 8.1 + Farman.... 7 50 1,200 8.9 + Voisin.... 8 50 1,200 6.6 +</pre> + <p> + In giving the depth dimensions the length over all—from the extreme + edge of the front auxiliary plane to the extreme tip of the rear is + stated. Thus while the dimensions of the main planes of the Wright machine + are 41 feet spread by 6 1/2 feet in depth, the depth over all is 30.7. + </p> + <p> + Figuring Out the Details. + </p> + <p> + With this data as a guide it should be comparatively easy to decide upon + the dimensions of the machine required. In arriving at the maximum lifting + capacity the weight of the operator must be added. Assuming this to + average 170 pounds the method of procedure would be as follows: + </p> + <p> + Add the weight of the operator to the weight of the complete machine. The + new Wright machine complete weighs 900 pounds. This, plus 170, the weight + of the operator, gives a total of 1,070 pounds. There are 538 square feet + of supporting surface, or practically one square foot of surface area to + each two pounds of load. + </p> + <p> + There are some machines, notably the Bleriot, in which the supporting + power is much greater. In this latter instance we find a surface area of + 150 1/2 square feet carrying a load of 680 plus 170, or an aggregate of + 850 pounds. This is the equivalent of five pounds to the square foot. This + ratio is phenomenally large, and should not be taken as a guide by + amateurs. + </p> + <p> + The Matter of Passengers. + </p> + <p> + These deductions are based on each machine carrying one passenger, which + is admittedly the limit at present of the monoplanes like those operated + for record-making purposes by Santos-Dumont and Bleriot. The biplanes, + however, have a two-passenger capacity, and this adds materially to the + proportion of their weight-sustaining power as compared with the surface + area. In the following statement all the machines are figured on the + one-passenger basis. Curtiss and Wright have carried two passengers on + numerous occasions, and an extra 170 pounds should therefore be added to + the total weight carried, which would materially increase the capacity. + Even with the two-passenger load the limit is by no means reached, but as + experiments have gone no further it is impossible to make more accurate + figures. + </p> + <p> + Average Proportions of Load. + </p> + <p> + It will be interesting, before proceeding to lay out the dimension + details, to make a comparison of the proportion of load effect with the + supporting surfaces of various well-known machines. Here are the figures: + </p> + <p> + Santos-Dumont—A trifle under four pounds per square foot. + </p> + <p> + Bleriot—Five pounds. + </p> + <p> + R. E. P.—Five pounds. + </p> + <p> + Antoinette—About two and one-quarter pounds. + </p> + <p> + Curtiss—About two and one-half pounds. + </p> + <p> + Wright—Two and one-quarter pounds. + </p> + <p> + Farman—A trifle over three pounds. + </p> + <p> + Voisin—A little under two and one-half pounds. + </p> + <p> + Importance of Engine Power. + </p> + <p> + While these figures are authentic, they are in a way misleading, as the + important factor of engine power is not taken into consideration. Let us + recall the fact that it is the engine power which keeps the machine in + motion, and that it is only while in motion that the machine will remain + suspended in the air. Hence, to attribute the support solely to the + surface area is erroneous. True, that once under headway the planes + contribute largely to the sustaining effect, and are absolutely essential + in aerial navigation—the motor could not rise without them—still, + when it comes to a question of weight-sustaining power, we must also + figure on the engine capacity. + </p> + <p> + In the Wright machine, in which there is a lifting capacity of + approximately 2 1/4 pounds to the square foot of surface area, an engine + of only 25 horsepower is used. In the Curtiss, which has a lifting + capacity of 2 1/2 pounds per square foot, the engine is of 50 horsepower. + This is another of the peculiarities of aerial construction and + navigation. Here we have a gain of 1/4 pound in weight-lifting capacity + with an expenditure of double the horsepower. It is this feature which + enables Curtiss to get along with a smaller surface area of supporting + planes at the expense of a big increase in engine power. Proper Weight of + Machine. + </p> + <p> + As a general proposition the most satisfactory machine for amateur + purposes will be found to be one with a total weight-sustaining power of + about 1,200 pounds. Deducting 170 pounds as the weight of the operator, + this will leave 1,030 pounds for the complete motor-equipped machine, and + it should be easy to construct one within this limit. This implies, of + course, that due care will be taken to eliminate all superfluous weight by + using the lightest material compatible with strength and safety. + </p> + <p> + This plan will admit of 686 pounds weight in the frame work, coverings, + etc., and 344 for the motor, propeller, etc., which will be ample. Just + how to distribute the weight of the planes is a matter which must be left + to the ingenuity of the builder. + </p> + <p> + Comparison of Bird Power. + </p> + <p> + There is an interesting study in the accompanying illustration. Note that + the surface area of the albatross is much smaller than that of the + vulture, although the wing spread is about the same. Despite this the + albatross accomplishes fully as much in the way of flight and soaring as + the vulture. Why? Because the albaboss is quicker and more powerful in + action. It is the application of this same principle in flying machines + which enables those of great speed and power to get along with less + supporting surface than those of slower movement. + </p> + <p> + Measurements of Curtiss Machine. + </p> + <p> + Some idea of framework proportion may be had from the following + description of the Curtiss machine. The main planes have a spread (width) + of 29 feet, and are 4 1/2 feet deep. The front double surface horizontal + rudder is 6x2 feet, with an area of 24 square feet. To the rear of the + main planes is a single surface horizontal plane 6x2 feet, with an area of + 12 square feet. In connection with this is a vertical rudder 2 1/2 feet + square. Two movable ailerons, or balancing planes, are placed at the + extreme ends of the upper planes. These are 6x2 feet, and have a combined + area of 24 square feet. There is also a triangular shaped vertical + steadying surface in connection with the front rudder. + </p> + <p> + Thus we have a total of 195 square feet, but as the official figures are + 258, and the size of the triangular-shaped steadying surface is unknown, + we must take it for granted that this makes up the difference. In the + matter of proportion the horizontal double-plane rudder is about one-tenth + the size of the main plane, counting the surface area of only one plane, + the vertical rudder one-fortieth, and the ailerons one-twentieth. + </p> + <p> + <a name="link2HCH0011" id="link2HCH0011"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XI. PLANE AND RUDDER CONTROL. + </h2> + <p> + Having constructed and equipped your machine, the next thing is to decide + upon the method of controlling the various rudders and auxiliary planes by + which the direction and equilibrium and ascending and descending of the + machine are governed. + </p> + <p> + The operator must be in position to shift instantaneously the position of + rudders and planes, and also to control the action of the motor. This + latter is supposed to work automatically and as a general thing does so + with entire satisfaction, but there are times when the supply of gasolene + must be regulated, and similar things done. Airship navigation calls for + quick action, and for this reason the matter of control is an important + one—it is more than important; it is vital. + </p> + <p> + Several Methods of Control. + </p> + <p> + Some aviators use a steering wheel somewhat after the style of that used + in automobiles, and by this not only manipulate the rudder planes, but + also the flow of gasolene. Others employ foot levers, and still others, + like the Wrights, depend upon hand levers. + </p> + <p> + Curtiss steers his aeroplane by means of a wheel, but secures the desired + stabilizing effect with an ingenious jointed chair-back. This is so + arranged that by leaning toward the high point of his wing planes the + aeroplane is restored to an even keel. The steering post of the wheel is + movable backward and forward, and by this motion elevation is obtained. + </p> + <p> + The Wrights for some time used two hand levers, one to steer by and warp + the flexible tips of the planes, the other to secure elevation. They have + now consolidated all the functions in one lever. Bleriot also uses the + single lever control. + </p> + <p> + Farman employs a lever to actuate the rudders, but manipulates the + balancing planes by foot levers. + </p> + <p> + Santos-Dumont uses two hand levers with which to steer and elevate, but + manipulates the planes by means of an attachment to the back of his outer + coat. + </p> + <p> + Connection With the Levers. + </p> + <p> + No matter which particular method is employed, the connection between the + levers and the object to be manipulated is almost invariably by wire. For + instance, from the steering levers (or lever) two wires connect with + opposite sides of the rudder. As a lever is moved so as to draw in the + right-hand wire the rudder is drawn to the right and vice versa. The + operation is exactly the same as in steering a boat. It is the same way in + changing the position of the balancing planes. A movement of the hands or + feet and the machine has changed its course, or, if the equilibrium is + threatened, is back on an even keel. + </p> + <p> + Simple as this seems it calls for a cool head, quick eye, and steady hand. + The least hesitation or a false movement, and both aviator and craft are + in danger. + </p> + <p> + Which Method is Best? + </p> + <p> + It would be a bold man who would attempt to pick out any one of these + methods of control and say it was better than the others. As in other + sections of aeroplane mechanism each method has its advocates who dwell + learnedly upon its advantages, but the fact remains that all the various + plans work well and give satisfaction. + </p> + <p> + What the novice is interested in knowing is how the control is effected, + and whether he has become proficient enough in his manipulation of it to + be absolutely dependable in time of emergency. No amateur should attempt a + flight alone, until he has thoroughly mastered the steering and plane + control. If the services and advice of an experienced aviator are not to + be had the novice should mount his machine on some suitable supports so it + will be well clear of the ground, and, getting into the operator's seat, + proceed to make himself well acquainted with the operation of the steering + wheel and levers. + </p> + <p> + Some Things to Be Learned. + </p> + <p> + He will soon learn that certain movements of the steering gear produce + certain effects on the rudders. If, for instance, his machine is equipped + with a steering wheel, he will find that turning the wheel to the right + turns the aeroplane in the same direction, because the tiller is brought + around to the left. In the same way he will learn that a given movement of + the lever throws the forward edge of the main plane upward, and that the + machine, getting the impetus of the wind under the concave surfaces of the + planes, will ascend. In the same way it will quickly become apparent to + him that an opposite movement of the lever will produce an opposite effect—the + forward edges of the planes will be lowered, the air will be "spilled" out + to the rear, and the machine will descend. + </p> + <p> + The time expended in these preliminary lessons will be well spent. It + would be an act of folly to attempt to actually sail the craft without + them. + </p> + <p> + <a name="link2HCH0012" id="link2HCH0012"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XII. HOW TO USE THE MACHINE. + </h2> + <p> + It is a mistaken idea that flying machines must be operated at extreme + altitudes. True, under the impetus of handsome prizes, and the incentive + to advance scientific knowledge, professional aviators have ascended to + considerable heights, flights at from 500 to 1,500 feet being now common + with such experts as Farman, Bleriot, Latham, Paulhan, Wright and Curtiss. + The altitude record at this time is about 4,165 feet, held by Paulhan. + </p> + <p> + One of the instructions given by experienced aviators to pupils, and for + which they insist upon implicit obeyance, is: "If your machine gets more + than 30 feet high, or comes closer to the ground than 6 feet, descend at + once." Such men as Wright and Curtiss will not tolerate a violation of + this rule. If their instructions are not strictly complied with they + decline to give the offender further lessons. + </p> + <p> + Why This Rule Prevails. + </p> + <p> + There is good reason for this precaution. The higher the altitude the more + rarefied (thinner) becomes the air, and the less sustaining power it has. + Consequently the more difficult it becomes to keep in suspension a given + weight. When sailing within 30 feet of the ground sustentation is + comparatively easy and, should a fall occur, the results are not likely to + be serious. On the other hand, sailing too near the ground is almost as + objectionable in many ways as getting up too high. If the craft is + navigated too close to the ground trees, shrubs, fences and other + obstructions are liable to be encountered. There is also the handicap of + contrary air currents diverted by the obstructions referred to, and which + will be explained more fully further on. + </p> + <p> + How to Make a Start. + </p> + <p> + Taking it for granted that the beginner has familiarized himself with the + manipulation of the machine, and especially the control mechanism, the + next thing in order is an actual flight. It is probable that his machine + will be equipped with a wheeled alighting gear, as the skids used by the + Wrights necessitate the use of a special starting track. In this respect + the wheeled machine is much easier to handle so far as novices are + concerned as it may be easily rolled to the trial grounds. This, as in the + case of the initial experiments, should be a clear, reasonably level + place, free from trees, fences, rocks and similar obstructions with which + there may be danger of colliding. + </p> + <p> + The beginner will need the assistance of three men. One of these should + take his position in the rear of the machine, and one at each end. On + reaching the trial ground the aviator takes his seat in the machine and, + while the men at the ends hold it steady the one in the rear assists in + retaining it until the operator is ready. In the meantime the aviator has + started his motor. Like the glider the flying machine, in order to + accomplish the desired results, should be headed into the wind. + </p> + <p> + When the Machine Rises. + </p> + <p> + Under the impulse of the pushing movement, and assisted by the motor + action, the machine will gradually rise from the ground—provided it + has been properly proportioned and put together, and everything is in + working order. This is the time when the aviator requires a cool head, At + a modest distance from the ground use the control lever to bring the + machine on a horizontal level and overcome the tendency to rise. The exact + manipulation of this lever depends upon the method of control adopted, and + with this the aviator is supposed to have thoroughly familiarized himself + as previously advised in Chapter XI. + </p> + <p> + It is at this juncture that the operator must act promptly, but with the + perfect composure begotten of confidence. One of the great drawbacks in + aviation by novices is the tendency to become rattled, and this is much + more prevalent than one might suppose, even among men who, under other + conditions, are cool and confident in their actions. + </p> + <p> + There is something in the sensation of being suddenly lifted from the + ground, and suspended in the air that is disconcerting at the start, but + this will soon wear off if the experimenter will keep cool. A few + successful flights no matter how short they may be, will put a lot of + confidence into him. + </p> + <p> + Make Your Flights Short. + </p> + <p> + Be modest in your initial flights. Don't attempt to match the records of + experienced men who have devoted years to mastering the details of + aviation. Paulhan, Farman, Bleriot, Wright, Curtiss, and all the rest of + them began, and practiced for years, in the manner here described, being + content to make just a little advancement at each attempt. A flight of 150 + feet, cleanly and safely made, is better as a beginning than one of 400 + yards full of bungling mishaps. + </p> + <p> + And yet these latter have their uses, provided the operator is of a + discerning mind and can take advantage of them as object lessons. But, it + is not well to invite them. They will occur frequently enough under the + most favorable conditions, and it is best to have them come later when the + feeling of trepidation and uncertainty as to what to do has worn off. + </p> + <p> + Above all, don't attempt to fly too high. Keep within a reasonable + distance from the ground—about 25 or 30 feet. This advice is not + given solely to lessen the risk of serious accident in case of collapse, + but mainly because it will assist to instill confidence in the operator. + </p> + <p> + It is comparatively easy to learn to swim in shallow water, but the + knowledge that one is tempting death in deep water begets timidity. + </p> + <p> + Preserving the Equilibrium. + </p> + <p> + After learning how to start and stop, to ascend and descend, the next + thing to master is the art of preserving equilibrium, the knack of keeping + the machine perfectly level in the air—on an "even keel," as a + sailor would say. This simile is particularly appropriate as all aviators + are in reality sailors, and much more daring ones than those who course + the seas. The latter are in craft which are kept afloat by the buoyancy of + the water, whether in motion or otherwise and, so long as normal + conditions prevail, will not sink. Aviators sail the air in craft in which + constant motion must be maintained in order to ensure flotation. + </p> + <p> + The man who has ridden a bicycle or motorcycle around curves at anything + like high speed, will have a very good idea as to the principle of + maintaining equilibrium in an airship. He knows that in rounding curves + rapidly there is a marked tendency to change the direction of the motion + which will result in an upset unless he overcomes it by an inclination of + his body in an opposite direction. This is why we see racers lean well + over when taking the curves. It simply must be done to preserve the + equilibrium and avoid a spill. + </p> + <p> + How It Works In the Air. + </p> + <p> + If the equilibrium of an airship is disturbed to an extent which + completely overcomes the center of gravity it falls according to the + location of the displacement. If this displacement, for instance, is at + either end the apparatus falls endways; if it is to the front or rear, the + fall is in the corresponding direction. + </p> + <p> + Owing to uncertain air currents—the air is continually shifting and + eddying, especially within a hundred feet or so of the earth—the + equilibrium of an airship is almost constantly being disturbed to some + extent. Even if this disturbance is not serious enough to bring on a fall + it interferes with the progress of the machine, and should be overcome at + once. This is one of the things connected with aerial navigation which + calls for prompt, intelligent action. + </p> + <p> + Frequently, when the displacement is very slight, it may be overcome, and + the craft immediately righted by a mere shifting of the operator's body. + Take, for illustration, a case in which the extreme right end of the + machine becomes lowered a trifle from the normal level. It is possible to + bring it back into proper position by leaning over to the left far enough + to shift the weight to the counter-balancing point. The same holds good as + to minor front or rear displacements. + </p> + <p> + When Planes Must Be Used. + </p> + <p> + There are other displacements, however, and these are the most frequent, + which can be only overcome by manipulation of the stabilizing planes. The + method of procedure depends upon the form of machine in use. The Wright + machine, as previously explained, is equipped with plane ends which are so + contrived as to admit of their being warped (position changed) by means of + the lever control. These flexible tip planes move simultaneously, but in + opposite directions. As those on one end rise, those on the other end fall + below the level of the main plane. By this means air is displaced at one + point, and an increased amount secured in another. + </p> + <p> + This may seem like a complicated system, but its workings are simple when + once understood. It is by the manipulation or warping of these flexible + tips that transverse stability is maintained, and any tendency to + displacement endways is overcome. Longitudinal stability is governed by + means of the front rudder. + </p> + <p> + Stabilizing planes of some form are a feature, and a necessary feature, on + all flying machines, but the methods of application and manipulation vary + according to the individual ideas of the inventors. They all tend, + however, toward the same end—the keeping of the machine perfectly + level when being navigated in the air. + </p> + <p> + When to Make a Flight. + </p> + <p> + A beginner should never attempt to make a flight when a strong wind is + blowing. The fiercer the wind, the more likely it is to be gusty and + uncertain, and the more difficult it will be to control the machine. Even + the most experienced and daring of aviators find there is a limit to wind + speed against which they dare not compete. This is not because they lack + courage, but have the sense to realize that it would be silly and useless. + </p> + <p> + The novice will find a comparatively still day, or one when the wind is + blowing at not to exceed 15 miles an hour, the best for his experiments. + The machine will be more easily controlled, the trip will be safer, and + also cheaper as the consumption of fuel increases with the speed of the + wind against which the aeroplane is forced. + </p> + <p> + <a name="link2HCH0013" id="link2HCH0013"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XIII. PECULIARITIES OF AIRSHIP POWER. + </h2> + <p> + As a general proposition it takes much more power to propel an airship a + given number of miles in a certain time than it does an automobile + carrying a far heavier load. Automobiles with a gross load of 4,000 + pounds, and equipped with engines of 30 horsepower, have travelled + considerable distances at the rate of 50 miles an hour. This is an + equivalent of about 134 pounds per horsepower. For an average modern + flying machine, with a total load, machine and passengers, of 1,200 + pounds, and equipped with a 50-horsepower engine, 50 miles an hour is the + maximum. Here we have the equivalent of exactly 24 pounds per horsepower. + Why this great difference? + </p> + <p> + No less an authority than Mr. Octave Chanute answers the question in a + plain, easily understood manner. He says: + </p> + <p> + "In the case of an automobile the ground furnishes a stable support; in + the case of a flying machine the engine must furnish the support and also + velocity by which the apparatus is sustained in the air." + </p> + <p> + Pressure of the Wind. + </p> + <p> + Air pressure is a big factor in the matter of aeroplane horsepower. + Allowing that a dead calm exists, a body moving in the atmosphere creates + more or less resistance. The faster it moves, the greater is this + resistance. Moving at the rate of 60 miles an hour the resistance, or wind + pressure, is approximately 50 pounds to the square foot of surface + presented. If the moving object is advancing at a right angle to the wind + the following table will give the horsepower effect of the resistance per + square foot of surface at various speeds. + </p> +<pre xml:space="preserve"> + Horse Power + Miles per Hour per sq. foot + 10 0.013 + 15 0 044 + 20 0.105 + 25 0.205 + 30 0.354 + 40 0.84 + 50 1.64 + 60 2.83 + 80 6.72 + 100 13.12 +</pre> + <p> + While the pressure per square foot at 60 miles an hour, is only 1.64 + horsepower, at 100 miles, less than double the speed, it has increased to + 13.12 horsepower, or exactly eight times as much. In other words the + pressure of the wind increases with the square of the velocity. Wind at 10 + miles an hour has four times more pressure than wind at 5 miles an hour. + </p> + <p> + How to Determine Upon Power. + </p> + <p> + This element of air resistance must be taken into consideration in + determining the engine horsepower required. When the machine is under + headway sufficient to raise it from the ground (about 20 miles an hour), + each square foot of surface resistance, will require nearly nine-tenths of + a horsepower to overcome the wind pressure, and propel the machine through + the air. As shown in the table the ratio of power required increases + rapidly as the speed increases until at 60 miles an hour approximately 3 + horsepower is needed. + </p> + <p> + In a machine like the Curtiss the area of wind-exposed surface is about 15 + square feet. On the basis of this resistance moving the machine at 40 + miles an hour would require 12 horsepower. This computation covers only + the machine's power to overcome resistance. It does not cover the power + exerted in propelling the machine forward after the air pressure is + overcome. To meet this important requirement Mr. Curtiss finds it + necessary to use a 50-horsepower engine. Of this power, as has been + already stated, 12 horsepower is consumed in meeting the wind pressure, + leaving 38 horsepower for the purpose of making progress. + </p> + <p> + The flying machine must move faster than the air to which it is opposed. + Unless it does this there can be no direct progress. If the two forces are + equal there is no straight-ahead advancement. Take, for sake of + illustration, a case in which an aeroplane, which has developed a speed of + 30 miles an hour, meets a wind velocity of equal force moving in an + opposite direction. What is the result? There can be no advance because it + is a contest between two evenly matched forces. The aeroplane stands + still. The only way to get out of the difficulty is for the operator to + wait for more favorable conditions, or bring his machine to the ground in + the usual manner by manipulation of the control system. + </p> + <p> + Take another case. An aeroplane, capable of making 50 miles an hour in a + calm, is met by a head wind of 25 miles an hour. How much progress does + the aeroplane make? Obviously it is 25 miles an hour over the ground. + </p> + <p> + Put the proposition in still another way. If the wind is blowing harder + than it is possible for the engine power to overcome, the machine will be + forced backward. + </p> + <p> + Wind Pressure a Necessity. + </p> + <p> + While all this is true, the fact remains that wind pressure, up to a + certain stage, is an absolute necessity in aerial navigation. The + atmosphere itself has very little real supporting power, especially if + inactive. If a body heavier than air is to remain afloat it must move + rapidly while in suspension. + </p> + <p> + One of the best illustrations of this is to be found in skating over thin + ice. Every school boy knows that if he moves with speed he may skate or + glide in safety across a thin sheet of ice that would not begin to bear + his weight if he were standing still. Exactly the same proposition obtains + in the case of the flying machine. + </p> + <p> + The non-technical reason why the support of the machine becomes easier as + the speed increases is that the sustaining power of the atmosphere + increases with the resistance, and the speed with which the object is + moving increases this resistance. With a velocity of 12 miles an hour the + weight of the machine is practically reduced by 230 pounds. Thus, if under + a condition of absolute calm it were possible to sustain a weight of 770 + pounds, the same atmosphere would sustain a weight of 1,000 pounds moving + at a speed of 12 miles an hour. This sustaining power increases rapidly as + the speed increases. While at 12 miles the sustaining power is figured at + 230 pounds, at 24 miles it is four times as great, or 920 pounds. + </p> + <p> + Supporting Area of Birds. + </p> + <p> + One of the things which all producing aviators seek to copy is the motive + power of birds, particularly in their relation to the area of support. + Close investigation has established the fact that the larger the bird the + less is the relative area of support required to secure a given result. + This is shown in the following table: + </p> +<pre xml:space="preserve"> + Supporting + Weight Surface Horse area + Bird in lbs. in sq. feet power per lb. + Pigeon 1.00 0.7 0.012 0.7 + Wild Goose 9.00 2.65 0.026 0.2833 + Buzzard 5.00 5.03 0.015 1.06 + Condor 17.00 9.85 0.043 0.57 +</pre> + <p> + So far as known the condor is the largest of modern birds. It has a wing + stretch of 10 feet from tip to tip, a supporting area of about 10 square + feet, and weighs 17 pounds. It. is capable of exerting perhaps 1-30 + horsepower. (These figures are, of course, approximate.) Comparing the + condor with the buzzard with a wing stretch of 6 feet, supporting area of + 5 square feet, and a little over 1-100 horsepower, it may be seen that, + broadly speaking, the larger the bird the less surface area (relatively) + is needed for its support in the air. + </p> + <p> + Comparison With Aeroplanes. + </p> + <p> + If we compare the bird figures with those made possible by the development + of the aeroplane it will be readily seen that man has made a wonderful + advance in imitating the results produced by nature. Here are the figures: + </p> +<pre xml:space="preserve"> + Supporting + Weight Surface Horse area + Machine in lbs. in sq. feet power per lb. + Santos-Dumont.. 350 110.00 30 0.314 + Bleriot..... 700 150.00 25 0.214 + Antoinette.... 1,200 538.00 50 0.448 + Curtiss..... 700 258.00 60 0.368 + Wright.....<a href="#linknote-4" name="linknoteref-4" id="linknoteref-4">4</a> 1,100 538.00 25 0.489 + Farman...... 1,200 430.00 50 0.358 + Voisin...... 1,200 538.00 50 0.448 +</pre> + <p> + While the average supporting surface is in favor of the aeroplane, this is + more than overbalanced by the greater amount of horsepower required for + the weight lifted. The average supporting surface in birds is about + three-quarters of a square foot per pound. In the average aeroplane it is + about one-half square foot per pound. On the other hand the average + aeroplane has a lifting capacity of 24 pounds per horsepower, while the + buzzard, for instance, lifts 5 pounds with 15-100 of a horsepower. If the + Wright machine—which has a lifting power of 50 pounds per horsepower—should + be alone considered the showing would be much more favorable to the + aeroplane, but it would not be a fair comparison. + </p> + <p> + More Surface, Less Power. + </p> + <p> + Broadly speaking, the larger the supporting area the less will be the + power required. Wright, by the use of 538 square feet of supporting + surface, gets along with an engine of 25 horsepower. Curtiss, who uses + only 258 square feet of surface, finds an engine of 50 horsepower is + needed. Other things, such as frame, etc., being equal, it stands to + reason that a reduction in the area of supporting surface will + correspondingly reduce the weight of the machine. Thus we have the Curtiss + machine with its 258 square feet of surface, weighing only 600 pounds + (without operator), but requiring double the horsepower of the Wright + machine with 538 square feet of surface and weighing 1,100 pounds. This + demonstrates in a forceful way the proposition that the larger the surface + the less power will be needed. + </p> + <p> + But there is a limit, on account of its bulk and awkwardness in handling, + beyond which the surface area cannot be enlarged. Otherwise it might be + possible to equip and operate aeroplanes satisfactorily with engines of 15 + horsepower, or even less. + </p> + <p> + The Fuel Consumption Problem. + </p> + <p> + Fuel consumption is a prime factor in the production of engine power. The + veriest mechanical tyro knows in a general way that the more power is + secured the more fuel must be consumed, allowing that there is no + difference in the power-producing qualities of the material used. But few + of us understand just what the ratio of increase is, or how it is caused. + This proposition is one of keen interest in connection with aviation. + </p> + <p> + Let us cite a problem which will illustrate the point quoted: Allowing + that it takes a given amount of gasolene to propel a flying machine a + given distance, half the way with the wind, and half against it, the wind + blowing at one-half the speed of the machine, what will be the increase in + fuel consumption? + </p> + <p> + Increase of Thirty Per Cent. + </p> + <p> + On the face of it there would seem to be no call for an increase as the + resistance met when going against the wind is apparently offset by the + propulsive force of the wind when the machine is travelling with it. This, + however, is called faulty reasoning. The increase in fuel consumption, as + figured by Mr. F. W. Lanchester, of the Royal Society of Arts, will be + fully 30 per cent over the amount required for a similar operation of the + machine in still air. If the journey should be made at right angles to the + wind under the same conditions the increase would be 15 per cent. + </p> + <p> + In other words Mr. Lanchester maintains that the work done by the motor in + making headway against the wind for a certain distance calls for more + engine energy, and consequently more fuel by 30 per cent, than is saved by + the helping force of the wind on the return journey. + </p> + <p> + <a name="link2HCH0014" id="link2HCH0014"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XIV. ABOUT WIND CURRENTS, ETC. + </h2> + <p> + One of the first difficulties which the novice will encounter is the + uncertainty of the wind currents. With a low velocity the wind, some + distance away from the ground, is ordinarily steady. As the velocity + increases, however, the wind generally becomes gusty and fitful in its + action. This, it should be remembered, does not refer to the velocity of + the machine, but to that of the air itself. + </p> + <p> + In this connection Mr. Arthur T. Atherholt, president of the Aero Club of + Pennsylvania, in addressing the Boston Society of Scientific Research, + said: + </p> + <p> + "Probably the whirlpools of Niagara contain no more erratic currents than + the strata of air which is now immediately above us, a fact hard to + realize on account of its invisibility." + </p> + <p> + Changes In Wind Currents. + </p> + <p> + While Mr. Atherholt's experience has been mainly with balloons it is all + the more valuable on this account, as the balloons were at the mercy of + the wind and their varying directions afforded an indisputable guide as to + the changing course of the air currents. In speaking of this he said: + </p> + <p> + "In the many trips taken, varying in distance traversed from twenty-five + to 900 miles, it was never possible except in one instance to maintain a + straight course. These uncertain currents were most noticeable in the + Gordon-Bennett race from St. Louis in 1907. Of the nine aerostats + competing in that event, eight covered a more or less direct course due + east and southeast, whereas the writer, with Major Henry B. Hersey, first + started northwest, then north, northeast, east, east by south, and when + over the center of Lake Erie were again blown northwest notwithstanding + that more favorable winds were sought for at altitudes varying from 100 to + 3,000 meters, necessitating a finish in Canada nearly northeast of the + starting point. + </p> + <p> + "These nine balloons, making landings extending from Lake Ontario, Canada, + to Virginia, all started from one point within the same hour. + </p> + <p> + "The single exception to these roving currents occurred on October 21st, + of last year (1909) when, starting from Philadelphia, the wind shifted + more than eight degrees, the greatest variation being at the lowest + altitudes, yet at no time was a height of over a mile reached. + </p> + <p> + "Throughout the entire day the sky was overcast, with a thermometer + varying from fifty-seven degrees at 300 feet to forty-four degrees, + Fahrenheit at 5,000 feet, at which altitude the wind had a velocity of 43 + miles an hour, in clouds of a cirro-cumulus nature, a landing finally + being made near Tannersville, New York, in the Catskill mountains, after a + voyage of five and one-half hours. + </p> + <p> + "I have no knowledge of a recorded trip of this distance and duration, + maintained in practically a straight line from start to finish." + </p> + <p> + This wind disturbance is more noticeable and more difficult to contend + with in a balloon than in a flying machine, owing to the bulk and unwieldy + character of the former. At the same time it is not conducive to pleasant, + safe or satisfactory sky-sailing in an aeroplane. This is not stated with + the purpose of discouraging aviation, but merely that the operator may + know what to expect and be prepared to meet it. + </p> + <p> + Not only does the wind change its horizontal course abruptly and without + notice, but it also shifts in a vertical direction, one second blowing up, + and another down. No man has as yet fathomed the why and wherefore of this + erratic action; it is only known that it exists. + </p> + <p> + The most stable currents will be found from 50 to 100 feet from the earth, + provided the wind is not diverted by such objects as trees, rocks, etc. + That there are equally stable currents higher up is true, but they are + generally to be found at excessive altitudes. + </p> + <p> + How a Bird Meets Currents. + </p> + <p> + Observe a bird in action on a windy day and you will find it continually + changing the position of its wings. This is done to meet the varying gusts + and eddies of the air so that sustentation may be maintained and headway + made. One second the bird is bending its wings, altering the angle of + incidence; the next it is lifting or depressing one wing at a time. Still + again it will extend one wing tip in advance of the other, or be spreading + or folding, lowering or raising its tail. + </p> + <p> + All these motions have a meaning, a purpose. They assist the bird in + preserving its equilibrium. Without them the bird would be just as + helpless in the air as a human being and could not remain afloat. + </p> + <p> + When the wind is still, or comparatively so, a bird, having secured the + desired altitude by flight at an angle, may sail or soar with no wing + action beyond an occasional stroke when it desires to advance. But, in a + gusty, uncertain wind it must use its wings or alight somewhere. + </p> + <p> + Trying to Imitate the Bird. + </p> + <p> + Writing in <i>Fly</i>, Mr. William E. White says: + </p> + <p> + "The bird's flight suggests a number of ways in which the equilibrium of a + mechanical bird may be controlled. Each of these methods of control may be + effected by several different forms of mechanism. + </p> + <p> + "Placing the two wings of an aeroplane at an angle of three to five + degrees to each other is perhaps the oldest way of securing lateral + balance. This way readily occurs to anyone who watches a sea gull soaring. + The theory of the dihedral angle is that when one wing is lifted by a gust + of wind, the air is spilled from under it; while the other wing, being + correspondingly depressed, presents a greater resistance to the gust and + is lifted restoring the balance. A fixed angle of three to five degrees, + however, will only be sufficient for very light puffs of wind and to mount + the wings so that the whole wing may be moved to change the dihedral angle + presents mechanical difficulties which would be better avoided. + </p> + <p> + "The objection of mechanical impracticability applies to any plan to + preserve the balance by shifting weight or ballast. The center of gravity + should be lower than the center of the supporting surfaces, but cannot be + made much lower. It is a common mistake to assume that complete stability + will be secured by hanging the center of gravity very low on the principle + of the parachute. An aeroplane depends upon rapid horizontal motion for + its support, and if the center of gravity be far below the center of + support, every change of speed or wind pressure will cause the machine to + turn about its center of gravity, pitching forward and backward + dangerously. + </p> + <p> + Preserving Longitudinal Balance. + </p> + <p> + "The birds maintain longitudinal, or fore and aft balance, by elevating or + depressing their tails. Whether this action is secured in an aeroplane by + means of a horizontal rudder placed in the rear, or by deflecting planes + placed in front of the main planes, the principle is evidently the same. A + horizontal rudder placed well to the rear as in the Antoinette, Bleriot or + Santos-Dumont monoplanes, will be very much safer and steadier than the + deflecting planes in front, as in the Wright or Curtiss biplanes, but not + so sensitive or prompt in action. + </p> + <p> + "The natural fore and aft stability is very much strengthened by placing + the load well forward. The center of gravity near the front and a tail or + rudder streaming to the rear secures stability as an arrow is balanced by + the head and feathering. The adoption of this principle makes it almost + impossible for the aeroplane to turn over. + </p> + <p> + The Matter of Lateral Balance. + </p> + <p> + "All successful aeroplanes thus far have maintained lateral balance by the + principle of changing the angle of incidence of the wings. + </p> + <p> + "Other ways of maintaining the lateral balance, suggested by observation + of the flight of birds are—extending the wing tips and spilling the + air through the pinions; or, what is the same thing, varying the area of + the wings at their extremities. + </p> + <p> + "Extending the wing tips seems to be a simple and effective solution of + the problem. The tips may be made to swing outward upon a vertical axis + placed at the front edge of the main planes; or they may be hinged to the + ends of the main plane so as to be elevated or depressed through suitable + connections by the aviator; or they may be supported from a horizontal + axis parallel with the ends of the main planes so that they may swing + outward, the aviator controlling both tips through one lever so that as + one tip is extended the other is retracted. + </p> + <p> + "The elastic wing pinions of a bird bend easily before the wind, + permitting the gusts to glance off, but presenting always an even and + efficient curvature to the steady currents of the air." + </p> + <p> + High Winds Threaten Stability. + </p> + <p> + To ensure perfect stability, without control, either human or automatic, + it is asserted that the aeroplane must move faster than the wind is + blowing. So long as the wind is blowing at the rate of 30 miles an hour, + and the machine is traveling 40 or more, there will be little trouble as + regards equilibrium so far as wind disturbance goes, provided the wind + blows evenly and does not come in gusts or eddying currents. But when + conditions are reversed—when the machine travels only 30 miles an + hour and the wind blows at the rate of 50, look out for loss of + equilibrium. + </p> + <p> + One of the main reasons for this is that high winds are rarely steady; + they seldom blow for any length of time at the same speed. They are + usually "gusty," the gusts being a momentary movement at a higher speed. + Tornadic gusts are also formed by the meeting of two opposing currents, + causing a whirling motion, which makes stability uncertain. Besides, it is + not unusual for wind of high speed to suddenly change its direction + without warning. + </p> + <p> + Trouble With Vertical Columns. + </p> + <p> + Vertical currents—columns of ascending air—are frequently + encountered in unexpected places and have more or less tendency, according + to their strength, to make it difficult to keep the machine within a + reasonable distance from the ground. + </p> + <p> + These vertical currents are most generally noticeable in the vicinity of + steep cliffs, or deep ravines. In such instances they are usually of + considerable strength, being caused by the deflection of strong winds + blowing against the face of the cliffs. This deflection exerts a back + pressure which is felt quite a distance away from the point of origin, so + that the vertical current exerts an influence in forcing the machine + upward long before the cliff is reached. + </p> + <p> + <a name="link2HCH0015" id="link2HCH0015"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XV. THE ELEMENT OF DANGER. + </h2> + <p> + That there is an element of danger in aviation is undeniable, but it is + nowhere so great as the public imagines. Men are killed and injured in the + operation of flying machines just as they are killed and injured in the + operation of railways. Considering the character of aviation the + percentage of casualties is surprisingly small. + </p> + <p> + This is because the results following a collapse in the air are very much + different from what might be imagined. Instead of dropping to the ground + like a bullet an aeroplane, under ordinary conditions will, when anything + goes wrong, sail gently downward like a parachute, particularly if the + operator is cool-headed and nervy enough to so manipulate the apparatus as + to preserve its equilibrium and keep the machine on an even keel. + </p> + <p> + Two Fields of Safety. + </p> + <p> + At least one prominent aviator has declared that there are two fields of + safety—one close to the ground, and the other well up in the air. In + the first-named the fall will be a slight one with little chance of the + operator being seriously hurt. From the field of high altitude the the + descent will be gradual, as a rule, the planes of the machine serving to + break the force of the fall. With a cool-headed operator in control the + aeroplane may be even guided at an angle (about 1 to 8) in its descent so + as to touch the ground with a gliding motion and with a minimum of impact. + </p> + <p> + Such an experience, of course, is far from pleasant, but it is by no means + so dangerous as might appear. There is more real danger in falling from an + elevation of 75 or 100 feet than there is from 1,000 feet, as in the + former case there is no chance for the machine to serve as a parachute—its + contact with the ground comes too quickly. + </p> + <p> + Lesson in Recent Accidents. + </p> + <p> + Among the more recent fatalities in aviation are the deaths of Antonio + Fernandez and Leon Delagrange. The former was thrown to the ground by a + sudden stoppage of his motor, the entire machine seeming to collapse. It + is evident there were radical defects, not only in the motor, but in the + aeroplane framework as well. At the time of the stoppage it is estimated + that Fernandez was up about 1,500 feet, but the machine got no opportunity + to exert a parachute effect, as it broke up immediately. This would + indicate a fatal weakness in the structure which, under proper testing, + could probably have been detected before it was used in flight. + </p> + <p> + It is hard to say it, but Delagrange appears to have been culpable to + great degree in overloading his machine with a motor equipment much + heavier than it was designed to sustain. He was 65 feet up in the air when + the collapse occurred, resulting in his death. As in the case of Fernandez + common-sense precaution would doubtless have prevented the fatality. + </p> + <p> + Aviation Not Extra Hazardous. + </p> + <p> + All told there have been, up to the time of this writing (April, 1910), + just five fatalities in the history of power-driven aviation. This is + surprisingly low when the nature of the experiments, and the fact that + most of the operators were far from having extended experience, is taken + into consideration. Men like the Wrights, Curtiss, Bleriot, Farman, + Paulhan and others, are now experts, but there was a time, and it was not + long ago, when they were unskilled. That they, with numerous others less + widely known, should have come safely through their many experiments would + seem to disprove the prevailing idea that aviation is an extra hazardous + pursuit. + </p> + <p> + In the hands of careful, quick-witted, nervy men the sailing of an airship + should be no more hazardous than the sailing of a yacht. A vessel captain + with common sense will not go to sea in a storm, or navigate a weak, + unseaworthy craft. Neither should an aviator attempt to sail when the wind + is high and gusty, nor with a machine which has not been thoroughly tested + and found to be strong and safe. + </p> + <p> + Safer Than Railroading. + </p> + <p> + Statistics show that some 12,000 people are killed and 72,000 injured + every year on the railroads of the United States. Come to think it over it + is small wonder that the list of fatalities is so large. Trains are run at + high speeds, dashing over crossings at which collisions are liable to + occur, and over bridges which often collapse or are swept away by floods. + Still, while the number of casualties is large, the actual percentage is + small considering the immense number of people involved. + </p> + <p> + It is so in aviation. The number of casualties is remarkably small in + comparison with the number of flights made. In the hands of competent men + the sailing of an airship should be, and is, freer from risk of accident + than the running of a railway train. There are no rails to spread or + break, no bridges to collapse, no crossings at which collisions may occur, + no chance for some sleepy or overworked employee to misunderstand the + dispatcher's orders and cause a wreck. + </p> + <p> + Two Main Causes of Trouble. + </p> + <p> + The two main causes of trouble in an airship leading to disaster may be + attributed to the stoppage of the motor, and the aviator becoming rattled + so that he loses control of his machine. Modern ingenuity is fast + developing motors that almost daily become more and more reliable, and + experience is making aviators more and more self-confident in their + ability to act wisely and promptly in cases of emergency. Besides this a + satisfactory system of automatic control is in a fair way of being + perfected. + </p> + <p> + Occasionally even the most experienced and competent of men in all + callings become careless and by foolish action invite disaster. This is + true of aviators the same as it is of railroaders, men who work in + dynamite mills, etc. But in nearly every instance the responsibility rests + with the individual; not with the system. There are some men unfitted by + nature for aviation, just as there are others unfitted to be railway + engineers. + </p> + <p> + <a name="link2HCH0016" id="link2HCH0016"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XVI. RADICAL CHANGES BEING MADE. + </h2> + <p> + Changes, many of them extremely radical in their nature, are continually + being made by prominent aviators, and particularly those who have won the + greatest amount of success. Wonderful as the results have been few of the + aviators are really satisfied. Their successes have merely spurred them on + to new endeavors, the ultimate end being the development of an absolutely + perfect aircraft. + </p> + <p> + Among the men who have been thus experimenting are the Wright Brothers, + who last year (1909) brought out a craft totally different as regards + proportions and weight from the one used the preceding year. One marked + result was a gain of about 3 1/2 miles an hour in speed. + </p> + <p> + Dimensions of 1908 Machine. + </p> + <p> + The 1908 model aeroplane was 40 by 29 feet over all. The carrying + surfaces, that is, the two aerocurves, were 40 by 6 feet, having a + parabolical curve of one in twelve. With about 70 square feet of surface + in the rudders, the total surface given was about 550 square feet. The + engine, which is the invention of the Wright brothers, weighed, + approximately, 200 pounds, and gave about 25 horsepower at 1,400 + revolutions per minute. The total weight of the aeroplane, exclusive of + passenger, but inclusive of engine, was about 1,150 pounds. This result + showed a lift of a fraction over 2 1/4 pounds to the square foot of + carrying surface. The speed desired was 40 miles an hour, but the machine + was found to make only a scant 39 miles an hour. The upright struts were + about 7/8-inch thick, the skids, 2 1/2 by 1 1/4 inches thick. + </p> + <p> + Dimensions of 1909 Machine. + </p> + <p> + The 1909 aeroplane was built primarily for greater speed, and relatively + heavier; to be less at the mercy of the wind. This result was obtained as + follows: The aerocurves, or carrying surfaces, were reduced in dimensions + from 40 by 6 feet to 36 by 5 1/2 feet, the curve remaining the same, one + in twelve. The upright struts were cut from seven-eighths inch to + five-eighths inch, and the skids from two and one-half by one and + one-quarter to two and one-quarter by one and three-eighths inches. This + result shows that there were some 81 square feet of carrying surface + missing over that of last year's model. and some 25 pounds loss of weight. + Relatively, though, the 1909 model aeroplane, while actually 25 pounds + lighter, is really some 150 pounds heavier in the air than the 1908 model, + owing to the lesser square feet of carrying surface. + </p> + <p> + Some of the Results Obtained. + </p> + <p> + Reducing the carrying surfaces from 6 to 5 1/2 feet gave two results—first, + less carrying capacity; and, second, less head-on resistance, owing to the + fact that the extent of the parabolic curve in the carrying surfaces was + shortened. The "head-on" resistance is the retardance the aeroplane meets + in passing through the air, and is counted in square feet. In the 1908 + model the curve being one in twelve and 6 feet deep, gave 6 inches of + head-on resistance. The plane being 40 feet spread, gave 6 inches by 40 + feet, or 20 square feet of head-on resistance. Increasing this figure by a + like amount for each plane, and adding approximately 10 square feet for + struts, skids and wiring, we have a total of approximately, 50 square feet + of surface for "head-on" resistance. + </p> + <p> + In the 1909 aeroplane, shortening the curve 6 inches at the parabolic end + of the curve took off 1 inch of head-on resistance. Shortening the spread + of the planes took off between 3 and 4 square feet of head-on resistance. + Add to this the total of 7 square feet, less curve surface and about 1 + square foot, less wire and woodwork resistance, and we have a grand total + of, approximately, 12 square feet of less "head-on" resistance over the + 1908 model. + </p> + <p> + Changes in Engine Action. + </p> + <p> + The engine used in 1909 was the same one used in 1908, though some minor + changes were made as improvements; for instance, a make and break spark + was used, and a nine-tooth, instead of a ten-tooth magneto gear-wheel was + used. This increased the engine revolutions per minute from 1,200 to + 1,400, and the propeller revolutions per minute from 350 to 371, giving a + propeller thrust of, approximately, 170 foot pounds instead of 153, as was + had last year. + </p> + <p> + More Speed and Same Capacity. + </p> + <p> + One unsatisfactory feature of the 1909 model over that of 1908, + apparently, was the lack of inherent lateral stability. This was caused by + the lesser surface and lesser extent of curvatures at the portions of the + aeroplane which were warped. This defect did not show so plainly after Mr. + Orville Wright had become fully proficient in the handling of the new + machine, and with skillful management, the 1909 model aeroplane will be + just as safe and secure as the other though it will take a little more + practice to get that same degree of skill. + </p> + <p> + To sum up: The aeroplane used in 1909 was 25 pounds lighter, but really + about 150 pounds heavier in the air, had less head-on resistance, and + greater propeller thrust. The speed was increased from about 39 miles per + hour to 42 1/2 miles per hour. The lifting capacity remained about the + same, about 450 pounds capacity passenger-weight, with the 1908 machine. + In this respect, the loss of carrying surface was compensated for by the + increased speed. + </p> + <p> + During the first few flights it was plainly demonstrated that it would + need the highest skill to properly handle the aeroplane, as first one end + and then the other would dip and strike the ground, and either tear the + canvas or slew the aeroplane around and break a skid. + </p> + <p> + Wrights Adopt Wheeled Gears. + </p> + <p> + In still another important respect the Wrights, so far as the output of + one of their companies goes, have made a radical change. All the + aeroplanes turned out by the Deutsch Wright Gesellschaft, according to the + German publication, <i>Automobil-Welt</i>, will hereafter be equipped with + wheeled running gears and tails. The plan of this new machine is shown in + the illustration on page 145. The wheels are three in number, and are + attached one to each of the two skids, just under the front edge of the + planes, and one forward of these, attached to a cross-member. It is + asserted that with these wheels the teaching of purchasers to operate the + machines is much simplified, as the beginners can make short flights on + their own account without using the starting derrick. + </p> + <p> + This is a big concession for the Wrights to make, as they have hitherto + adhered stoutly to the skid gear. While it is true they do not control the + German company producing their aeroplanes, yet the nature of their + connection with the enterprise is such that it may be taken for granted no + radical changes in construction would be made without their approval and + consent. + </p> + <p> + Only Three Dangerous Rivals. + </p> + <p> + Official trials with the 1909 model smashed many records and leave the + Wright brothers with only three dangerous rivals in the field, and with + basic patents which cover the curve, warp and wing-tip devices found on + all the other makes of aeroplanes. These three rivals are the Curtiss and + Voisin biplane type and the Bleriot monoplane pattern. + </p> + <p> + The Bleriot monoplane is probably the most dangerous rival, as this make + of machine has a record of 54 miles per hour, has crossed the English + channel, and has lifted two passengers besides the operator. The latest + type of this machine only weighs 771.61 pounds complete, without + passengers, and will lift a total passenger weight of 462.97 pounds, which + is a lift of 5.21 pounds to the square foot. This is a better result than + those published by the Wright brothers, the best noted being 4.25 pounds + per square foot. + </p> + <p> + Other Aviators at Work. + </p> + <p> + The Wrights, however, are not alone in their efforts to promote the + efficiency of the flying machine. Other competent inventive aviators, + notably Curtiss, Voisin, Bleriot and Farman, are close after them. The + Wrights, as stated, have a marked advantage in the possession of patents + covering surface plane devices which have thus far been found + indispensable in flying machine construction. Numerous law suits growing + out of alleged infringements of these patents have been started, and + others are threatened. What effect these actions will have in deterring + aviators in general from proceeding with their experiments remains to be + seen. + </p> + <p> + In the meantime the four men named—Curtiss, Voisin, Bleriot and + Farman—are going ahead regardless of consequences, and the inventive + genius of each is so strong that it is reasonable to expect some + remarkable developments in the near future. + </p> + <p> + Smallest of Flying Machines. + </p> + <p> + To Santos Dumont must be given the credit of producing the smallest + practical flying machine yet constructed. True, he has done nothing + remarkable with it in the line of speed, but he has demonstrated the fact + that a large supporting surface is not an essential feature. + </p> + <p> + This machine is named "La Demoiselle." It is a monoplane of the dihedral + type, with a main plane on each side of the center. These main planes are + of 18 foot spread, and nearly 6 1/2 feet in depth, giving approximately + 115 feet of surface area. The total weight is 242 pounds, which is 358 + pounds less than any other machine which has been successfully used. The + total depth from front to rear is 26 feet. + </p> + <p> + The framework is of bamboo, strengthened and held taut with wire guys. + </p> + <p> + Have One Rule in Mind. + </p> + <p> + In this struggle for mastery in flying machine efficiency all the + contestants keep one rule in mind, and this is: + </p> + <p> + "The carrying capacity of an aeroplane is governed by the peripheral curve + of its carrying surfaces, plus the speed; and the speed is governed by the + thrust of the propellers, less the 'head-on' resistance." + </p> + <p> + Their ideas as to the proper means of approaching the proposition may, and + undoubtedly are, at variance, but the one rule in solving the problem of + obtaining the greatest carrying capacity combined with the greatest speed, + obtains in all instances. + </p> + <p> + <a name="link2HCH0017" id="link2HCH0017"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XVII. SOME OF THE NEW DESIGNS. + </h2> + <p> + Spurred on by the success attained by the more experienced and better + known aviators numerous inventors of lesser fame are almost daily + producing practical flying machines varying radically in construction from + those now in general use. + </p> + <p> + One of these comparatively new designs is the Van Anden biplane, made by + Frank Van Anden of Islip, Long Island, a member of the New York Aeronautic + Society. While his machine is wholly experimental, many successful short + flights were made with it last fall (1909). One flight, made October 19th, + 1909, is of particular interest as showing the practicability of an + automatic stabilizing device installed by the inventor. The machine was + caught in a sudden severe gust of wind and keeled over, but almost + immediately righted itself, thus demonstrating in a most satisfactory + manner the value of one new attachment. + </p> + <p> + Features of Van Anden Model. + </p> + <p> + In size the surfaces of the main biplane are 26 feet in spread, and 4 feet + in depth from front to rear. The upper and lower planes are 4 feet apart. + Silkolene coated with varnish is used for the coverings. Ribs (spruce) are + curved one inch to the foot, the deepest part of the curve (4 inches) + being one foot back from the front edge of the horizontal beam. Struts + (also of spruce, as is all the framework) are elliptical in shape. The + main beams are in three sections, nearly half round in form, and joined by + metal sleeves. + </p> + <p> + There is a two-surface horizontal rudder, 2x2x4 feet, in front. This is + pivoted at its lateral center 8 feet from the front edge of the main + planes. In the rear is another two-surface horizontal rudder 2x2x2 1/2 + feet, pivoted in the same manner as the front one, 15 feet from the rear + edges of the main planes. + </p> + <p> + Hinged to the rear central strut of the rear rudder is a vertical rudder 2 + feet high by 3 feet in length. + </p> + <p> + The Method of Control. + </p> + <p> + In the operation of these rudders—both front and rear—and the + elevation and depression of the main planes, the Curtiss system is + employed. Pushing the steering-wheel post outward depresses the front + edges of the planes, and brings the machine downward; pulling the + steering-wheel post inward elevates the front edges of the planes and + causes the machine to ascend. + </p> + <p> + Turning the steering wheel itself to the right swings the tail rudder to + the left, and the machine, obeying this like a boat, turns in the same + direction as the wheel is turned. By like cause turning the wheel to the + left turns the machine to the left. + </p> + <p> + Automatic Control of Wings. + </p> + <p> + There are two wing tips, each of 6 feet spread (length) and 2 feet from + front to rear. These are hinged half way between the main surfaces to the + two outermost rear struts. Cables run from these to an automatic device + working with power from the engine, which automatically operates the tips + with the tilting of the machine. Normally the wing tips are held + horizontal by stiff springs introduced in the cables outside of the + device. + </p> + <p> + It was the successful working of this device which righted the Van Anden + craft when it was overturned in the squall of October 19th, 1909. Previous + to that occurrence Mr. Van Anden had looked upon the device as purely + experimental, and had admitted that he had grave uncertainty as to how it + would operate in time of emergency. He is now quoted as being thoroughly + satisfied with its practicability. It is this automatic device which gives + the Van Anden machine at least one distinctively new feature. + </p> + <p> + While on this subject it will not be amiss to add that Mr. Curtiss does + not look kindly on automatic control. "I would rather trust to my own + action than that of a machine," he says. This is undoubtedly good logic so + far as Mr. Curtiss is concerned, but all aviators are not so cool-headed + and resourceful. + </p> + <p> + Motive Power of Van Anden. + </p> + <p> + A 50-horsepower "H-F" water cooled motor drives a laminated wood propeller + 6 feet in diameter, with a 17 degree pitch at the extremities, increasing + toward the hub. The rear end of the motor is about 6 inches back from the + rear transverse beam and the engine shaft is in a direct line with the + axes of the two horizontal rudders. An R. I. V. ball bearing carries the + shaft at this point. Flying, the motor turns at about 800 revolutions per + minute, delivering 180 pounds pull. A test of the motor running at 1,200 + showed a pull of 250 pounds on the scales. + </p> + <p> + Still Another New Aeroplane. + </p> + <p> + Another new aeroplane is that produced by A. M. Herring (an old-timer) and + W. S. Burgess, under the name of the Herring-Burgess. This is also + equipped with an automatic stability device for maintaining the balance + transversely. The curvature of the planes is also laid out on new lines. + That this new plan is effective is evidenced by the fact that the machine + has been elevated to an altitude of 40 feet by using one-half the power of + the 30-horsepower motor. + </p> + <p> + The system of rudder and elevation control is very simple. The aviator + sits in front of the lower plane, and extending his arms, grasps two + supports which extend down diagonally in front. On the under side of these + supports just beneath his fingers are the controls which operate the + vertical rudder, in the rear. Thus, if he wishes to turn to the right, he + presses the control under the fingers of his right hand; if to the left, + that under the fingers of his left hand. The elevating rudder is operated + by the aviator's right foot, the control being placed on a foot-rest. + </p> + <p> + Motor Is Extremely Light. + </p> + <p> + Not the least notable feature of the craft is its motor. Although + developing, under load, 30-horsepower, or that of an ordinary automobile, + it weighs, complete, hardly 100 pounds. Having occasion to move it a + little distance for inspection, Mr. Burgess picked it up and walked off + with it—cylinders, pistons, crankcase and all, even the magneto, + being attached. There are not many 30-horsepower engines which can be so + handled. Everything about it is reduced to its lowest terms of simplicity, + and hence, of weight. A single camshaft operates not only all of the inlet + and exhaust valves, but the magneto and gear water pump, as well. The + motor is placed directly behind the operator, and the propeller is + directly mounted on the crankshaft. + </p> + <p> + This weight of less than 100 pounds, it must be remembered, is not for the + motor alone; it includes the entire power plant equipment. + </p> + <p> + The "thrust" of the propeller is also extraordinary, being between 250 and + 260 pounds. The force of the wind displacement is strong enough to knock + down a good-sized boy as one youngster ascertained when he got behind the + propeller as it was being tested. He was not only knocked down but driven + for some distance away from the machine. The propeller has four blades + which are but little wider than a lath. + </p> + <p> + Machine Built by Students. + </p> + <p> + Students at the University of Pennsylvania, headed by Laurence J. Lesh, a + protege of Octave Chanute, have constructed a practical aeroplane of + ordinary maximum size, in which is incorporated many new ideas. The most + unique of these is to be found in the steering gear, and the provision + made for the accommodation of a pupil while taking lessons under an + experienced aviator. + </p> + <p> + Immediately back of the aviator is an extra seat and an extra steering + wheel which works in tandem style with the front wheel. By this + arrangement a beginner may be easily and quickly taught to have perfect + control of the machine. These tandem wheels are also handy for passengers + who may wish to operate the car independently of one another, it being + understood, of course, that there will be no conflict of action. + </p> + <p> + Frame Size and Engine Power. + </p> + <p> + The frame has 36 feet spread and measures 35 feet from the front edge to + the end of the tail in the rear. It is equipped with two rear propellers + operated by a Ramsey 8-cylinder motor of 50 horsepower, placed + horizontally across the lower plane, with the crank shaft running clear + through the engine. + </p> + <p> + The "Pennsylvania I" is the first two-propeller biplane chainless car, + this scheme having been adopted in order to avoid the crossing of chains. + The lateral control is by a new invention by Octave Chanute and Laurence + J. Lesh, for which Lesh is now applying for a patent. The device was + worked out before the Wright brothers' suit was begun, and is said to be + superior to the Wright warping or the Curtiss ailerons. The landing device + is also new in design. This aeroplane will weigh about 1,500 pounds, and + will carry fuel for a flight of 150 miles, and it is expected to attain a + speed of at least 45 miles an hour. + </p> + <p> + There are others, lots of them, too numerous in fact to admit of mention + in a book of this size. + </p> + <p> + <a name="link2HCH0018" id="link2HCH0018"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XVIII. DEMAND FOR FLYING MACHINES. + </h2> + <p> + As a commercial proposition the manufacture and sale of motor-equipped + aeroplanes is making much more rapid advance than at first obtained in the + similar handling of the automobile. Great, and even phenomenal, as was the + commercial development of the motor car, that of the flying machine is + even greater. This is a startling statement, but it is fully warranted by + the facts. + </p> + <p> + It is barely more than a year ago (1909) that attention was seriously + attracted to the motor-equipped aeroplane as a vehicle possible of + manipulation by others than professional aviators. Up to that time such + actual flights as were made were almost exclusively with the sole purpose + of demonstrating the practicability of the machine, and the merits of the + ideas as to shape, engine power, etc., of the various producers. + </p> + <p> + Results of Bleriot's Daring. + </p> + <p> + It was not until Bleriot flew across the straits of Dover on July 25th, + 1909, that the general public awoke to a full realization of the fact that + it was possible for others than professional aviators to indulge in + aviation. Bleriot's feat was accepted as proof that at last an absolutely + new means of sport, pleasure and research, had been practically developed, + and was within the reach of all who had the inclination, nerve and + financial means to adopt it. + </p> + <p> + From this event may be dated the birth of the modern flying machine into + the world of business. The automobile was taken up by the general public + from the very start because it was a proposition comparatively easy of + demonstration. There was nothing mysterious or uncanny in the fact that a + wheeled vehicle could be propelled on solid, substantial roads by means of + engine power. And yet it took (comparatively speaking) a long time to + really popularize the motor car. + </p> + <p> + Wonderful Results in a Year. + </p> + <p> + Men of large financial means engaged in the manufacture of automobiles, + and expended fortunes in attracting public attention to them through the + medium of advertisements, speed and road contests, etc. By these means a + mammoth business has been built up, but bringing this business to its + present proportions required years of patient industry and indomitable + pluck. + </p> + <p> + At this writing, less than a year from the day when Bleriot crossed the + channel, the actual sales of flying machines outnumber the actual sales of + automobiles in the first year of their commercial development. This may + appear incredible, but it is a fact as statistics will show. + </p> + <p> + In this connection we should take into consideration the fact that up to a + year ago there was no serious intention of putting flying machines on the + market; no preparations had been made to produce them on a commercial + scale; no money had been expended in advertisements with a view to selling + them. + </p> + <p> + Some of the Actual Results. + </p> + <p> + Today flying machines are being produced on a commercial basis, and there + is a big demand for them. The people making them are overcrowded with + orders. Some of the producers are already making arrangements to enlarge + their plants and advertise their product for sale the same as is being + done with automobiles, while a number of flying machine motor makers are + already promoting the sale of their wares in this way. + </p> + <p> + Here are a few actual figures of flying machine sales made by the more + prominent producers since July 25th, 1909. + </p> + <p> + Santos Dumont, 90 machines; Bleriot, 200; Farman, 130; Clemenceau-Wright, + 80; Voisin, 100; Antoinette, 100. Many of these orders have been filled by + delivery of the machines, and in others the construction work is under + way. + </p> + <p> + The foregoing are all of foreign make. In this country Curtiss and the + Wrights are engaged in similar work, but no actual figures of their output + are obtainable. + </p> + <p> + Larger Plants Are Necessary. + </p> + <p> + And this situation exists despite the fact that none of the producers are + really equipped with adequate plants for turning out their machines on a + modern, business-like basis. The demand was so sudden and unexpected that + it found them poorly prepared to meet it. This, however, is now being + remedied by the erection of special plants, the enlargement of others, and + the introduction of new machinery and other labor-saving conveniences. + </p> + <p> + Companies, with large capitalization, to engage in the exclusive + production of airships are being organized in many parts of the world. One + notable instance of this nature is worth quoting as illustrative of the + manner in which the production of flying machines is being commercialized. + This is the formation at Frankfort, Germany, of the Flugmaschine Wright, + G. m. b. H., with a capital of $119,000, the Krupps, of Essen, being + interested. + </p> + <p> + Prices at Which Machines Sell. + </p> + <p> + This wonderful demand from the public has come notwithstanding the fact + that the machines, owing to lack of facilities for wholesale production, + are far from being cheap. Such definite quotations as are made are on the + following basis: + </p> + <p> + Santos Dumont—List price $1,000, but owing to the rush of orders + agents are readily getting from $1,300 to $1,500. This is the smallest + machine made. + </p> + <p> + Bleriot—List price $2,500. This is for the cross-channel type, with + Anzani motor. + </p> + <p> + Antoinette—List price from $4,000 to $5,000, according to size. + </p> + <p> + Wright—List price $5,600. + </p> + <p> + Curtiss—List price $5,000. + </p> + <p> + There is, however, no stability in prices as purchasers are almost + invariably ready to pay a considerable premium to facilitate delivery. + </p> + <p> + The motor is the most expensive part of the flying machine. Motor prices + range from $500 to $2,000, this latter amount being asked for the Curtiss + engine. + </p> + <p> + Systematic Instruction of Amateurs. + </p> + <p> + In addition to the production of flying machines many of the experienced + aviators are making a business of the instruction of amateurs. Curtiss and + the Wrights in this country have a number of pupils, as have also the + prominent foreigners. Schools of instruction are being opened in various + parts of the world, not alone as private money-making ventures, but in + connection with public educational institutions. One of these latter is to + be found at the University of Barcelona, Spain. + </p> + <p> + The flying machine agent, the man who handles the machines on a + commission, has also become a known quantity, and will soon be as numerous + as his brother of the automobile. The sign "John Bird, agent for Skimmer's + Flying Machine," is no longer a curiosity. + </p> + <p> + Yes, the Airship Is Here. + </p> + <p> + From all of which we may well infer that the flying machine in practical + form has arrived, and that it is here to stay. It is no exaggeration to + say that the time is close at hand when people will keep flying machines + just as they now keep automobiles, and that pleasure jaunts will be fully + as numerous and popular. With the important item of practicability fully + demonstrated, "Come, take a trip in my airship," will have more real + significance than now attaches to the vapid warblings of the vaudeville + vocalist. + </p> + <p> + As a further evidence that the airship is really here, and that its + presence is recognized in a business way, the action of life and accident + insurance companies is interesting. Some of them are reconstructing their + policies so as to include a special waiver of insurance by aviators. + Anything which compels these great corporations to modify their policies + cannot be looked upon as a mere curiosity or toy. + </p> + <p> + It is some consolation to know that the movement in this direction is not + thus far widespread. Moreover it is more than probable that the + competition for business will eventually induce the companies to act more + liberally toward aviators, especially as the art of aviation advances. + </p> + <p> + <a name="link2HCH0019" id="link2HCH0019"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XIX. LAW OF THE AIRSHIP. + </h2> + <p> + Successful aviation has evoked some peculiar things in the way of legal + action and interpretation of the law. + </p> + <p> + It is well understood that a man's property cannot be used without his + consent. This is an old established principle in common law which holds + good today. + </p> + <p> + The limits of a man's property lines, however, have not been so well + understood by laymen. According to eminent legal authorities such as + Blackstone, Littleton and Coke, the "fathers of the law," the owner of + realty also holds title above and below the surface, and this theory is + generally accepted without question by the courts. + </p> + <p> + Rights of Property Owners. + </p> + <p> + In other words the owner of realty also owns the sky above it without + limit as to distance. He can dig as deep into his land, or go as high into + the air as he desires, provided he does not trespass upon or injure + similar rights of others. + </p> + <p> + The owner of realty may resist by force, all other means having failed, + any trespass upon, or invasion of his property. Other people, for + instance, may not enter upon it, or over or under it, without his express + permission and consent. There is only one exception, and this is in the + case of public utility corporations such as railways which, under the law + of eminent domain, may condemn a right of way across the property of an + obstinate owner who declines to accept a fair price for the privilege. + </p> + <p> + Privilege Sharply Confined. + </p> + <p> + The law of eminent domain may be taken advantage of only by corporations + which are engaged in serving the public. It is based upon the principle + that the advancement and improvement of a community is of more importance + and carries with it more rights than the interests of the individual + owner. But even in cases where the right of eminent domain is exercised + there can be no confiscation of the individual's property. + </p> + <p> + Exercising the right of eminent domain is merely obtaining by public + purchase what is held to be essential to the public good, and which cannot + be secured by private purchase. When eminent domain proceedings are + resorted to the court appoints appraisers who determine upon the value of + the property wanted, and this value (in money) is paid to the owner. + </p> + <p> + How It Affects Aviation. + </p> + <p> + It should be kept in mind that this privilege of the "right of eminent + domain" is accorded only to corporations which are engaged in serving the + public. Individuals cannot take advantage of it. Thus far all aviation has + been conducted by individuals; there are no flying machine or airship + corporations regularly engaged in the transportation of passengers, mails + or freight. + </p> + <p> + This leads up to the question "What would happen if realty owners + generally, or in any considerable numbers, should prohibit the navigation + of the air above their holdings?" It is idle to say such a possibility is + ridiculous—it is already an actuality in a few individual instances. + </p> + <p> + One property owner in New Jersey, a justice of the peace, maintains a + large sign on the roof of his house warning aviators that they must not + trespass upon his domain. That he is acting well within his rights in + doing this is conceded by legal authorities. + </p> + <p> + Hard to Catch Offenders. + </p> + <p> + But, suppose the alleged trespass is committed, what is the property owner + going to do about it? He must first catch the trespasser and this would be + a pretty hard job. He certainly could not overtake him, unless he kept a + racing aeroplane for this special purpose. It would be equally difficult + to identify the offender after the offense had been committed, even if he + were located, as aeroplanes carry no license numbers. + </p> + <p> + Allowing that the offender should be caught the only recourse of the + realty owner is an action for damages. He may prevent the commission of + the offense by force if necessary, but after it is committed he can only + sue for damages. And in doing this he would have a lot of trouble. + </p> + <p> + Points to Be Proven. + </p> + <p> + One of the first things the plaintiff would be called upon to prove would + be the elevation of the machine. If it were reasonably close to the ground + there would, of course, be grave risk of damage to fences, shrubbery, and + other property, and the court would be justified in holding it to be a + nuisance that should be suppressed. + </p> + <p> + If, on the other hand; the machine was well up in the air, but going + slowly, or hovering over the plaintiff's property, the court might be + inclined to rule that it could not possibly be a nuisance, but right here + the court would be in serious embarrassment. By deciding that it was not a + nuisance he would virtually override the law against invasion of a man's + property without his consent regardless of the nature of the invasion. By + the same decision he would also say in effect that, if one flying machine + could do this a dozen or more would have equal right to do the same thing. + While one machine hovering over a certain piece of property may be no + actual nuisance a dozen or more in the same position could hardly be + excused. + </p> + <p> + Difficult to Fix Damages. + </p> + <p> + Such a condition would tend to greatly increase the risk of accident, + either through collision, or by the carelessness of the aviators in + dropping articles which might cause damages to the people or property + below. In such a case it would undoubtedly be a nuisance, and in addition + to a fine, the offender would also be liable for the damages. + </p> + <p> + Taking it for granted that no actual damage is done, and the owner merely + sues on account of the invasion of his property, how is the amount of + compensation to be fixed upon? The owner has lost nothing; no part of his + possessions has been taken away; nothing has been injured or destroyed; + everything is left in exactly the same condition as before the invasion. + And yet, if the law is strictly interpreted, the offender is liable. + </p> + <p> + Right of Way for Airships. + </p> + <p> + Somebody has suggested the organization of flying-machine corporations as + common carriers, which would give them the right of eminent domain with + power to condemn a right of way. But what would they condemn? There is + nothing tangible in the air. Railways in condemning a right of way specify + tangible property (realty) within certain limits. How would an aviator + designate any particular right of way through the air a certain number of + feet in width, and a certain distance from the ground? + </p> + <p> + And yet, should the higher courts hold to the letter of the law and decide + that aviators have no right to navigate their craft over private property, + something will have to be done to get them out of the dilemma, as aviation + is too far advanced to be discarded. Fortunately there is little prospect + of any widespread antagonism among property owners so long as aviators + refrain from making nuisances of themselves. + </p> + <p> + Possible Solution Offered. + </p> + <p> + One possible solution is offered and that is to confine the path of + airships to the public highways so that nobody's property rights would be + invaded. In addition, as a matter of promoting safety for both operators + and those who may happen to be beneath the airships as they pass over a + course, adoption of the French rules are suggested. These are as follows: + </p> + <p> + Aeroplanes, when passing, must keep to the right, and pass at a distance + of at least 150 feet. They are free from this rule when flying at + altitudes of more than 100 feet. Every machine when flying at night or + during foggy weather must carry a green light on the right, and a red + light on the left, and a white headlight on the front. + </p> + <p> + These are sensible rules, but may be improved upon by the addition of a + signal system of some kind, either horn, whistle or bell. + </p> + <p> + Responsibility of Aviators. + </p> + <p> + Mr. Jay Carver Bossard, in recent numbers of <i>Fly</i>, brings out some + curious and interesting legal points in connection with aviation, among + which are the following: + </p> + <p> + "Private parties who possess aerial craft, and desire to operate the same + in aerial territory other than their own, must obtain from land owners + special permission to do so, such permission to be granted only by + agreement, founded upon a valid consideration. Otherwise, passing over + another's land will in each instance amount to a trespass. + </p> + <p> + "Leaving this highly technical side of the question, let us turn to + another view: the criminal and tort liability of owners and operators to + airship passengers. If A invites B to make an ascension with him in his + machine, and B, knowing that A is merely an enthusiastic amateur and far + from being an expert, accepts and is through A's innocent negligence + injured, he has no grounds for recovery. But if A contracts with B, to + transport him from one place to another, for a consideration, and B is + injured by the poor piloting of A, A would be liable to B for damages + which would result. Now in order to safeguard such people as B, curious to + the point of recklessness, the law will have to require all airship + operators to have a license, and to secure this license airship pilots + will have to meet certain requirements. Here again is a question. Who is + going to say whether an applicant is competent to pilot a balloon or + airship? + </p> + <p> + Fine for an Aeronaut. + </p> + <p> + "An aeroplane while maneuvering is suddenly caught by a treacherous gale + and swept to the ground. A crowd of people hasten over to see if the + aeronaut is injured, and in doing so trample over Tax-payer Smith's + garden, much to the detriment of his growing vegetables and flowers. Who + is liable for the damages? Queer as it may seem, a case very similar to + this was decided in 1823, in the New York supreme court, and it was held + that the aeronaut was liable upon the following grounds: 'To render one + man liable in trespass for the acts of others, it must appear either that + they acted in concert, or that the act of the one, ordinarily and + naturally produced the acts of the others, Ascending in a balloon is not + an unlawful act, but it is certain that the aeronaut has no control over + its motion horizontally, but is at the sport of the wind, and is to + descend when and how he can. His reaching the earth is a matter of hazard. + If his descent would according to the circumstances draw a crowd of people + around him, either out of curiosity, or for the purpose of rescuing him + from a perilous situation, all this he ought to have foreseen, and must be + responsible for.' + </p> + <p> + Air Not Really Free. + </p> + <p> + "The general belief among people is, that the air is free. Not only free + to breathe and enjoy, but free to travel in, and that no one has any + definite jurisdiction over, or in any part of it. Now suppose this were + made a legal doctrine. Would a murder perpetrated above the clouds have to + go unpunished? Undoubtedly. For felonies committed upon the high seas + ample provision is made for their punishment, but new provisions will have + to be made for crimes committed in the air. + </p> + <p> + Relations of Owner and Employee. + </p> + <p> + "It is a general rule of law that a master is bound to provide reasonably + safe tools, appliances and machines for his servant. How this rule is + going to be applied in cases of aeroplanes, remains to be seen. The + aeroplane owner who hires a professional aeronaut, that is, one who has + qualified as an expert, owes him very little legal duty to supply him with + a perfect aeroplane. The expert is supposed to know as much regarding the + machine as the owner, if not more, and his acceptance of his position + relieves the owner from liability. When the owner hires an amateur + aeronaut to run the aeroplane, and teaches him how to manipulate it, even + though the prescribed manner of manipulation will make flight safe, + nevertheless if the machine is visibly defective, or known to be so, any + injury which results to the aeronaut the owner is liable for. + </p> + <p> + As to Aeroplane Contracts. + </p> + <p> + "At the present time there are many orders being placed with aeroplane + manufacturing companies. There are some unique questions to be raised here + under the law of contract. It is an elementary principle of law that no + one can be compelled to complete a contract which in itself is impossible + to perform. For instance, a contract to row a boat across the Atlantic in + two weeks, for a consideration, could never be enforced because it is + within judicial knowledge that such an undertaking is beyond human power. + Again, contracts formed for the doing of acts contrary to nature are never + enforcible, and here is where our difficulty comes in. Is it possible to + build a machine or species of craft which will transport a person or goods + through the air? The courts know that balloons are practical; that is, + they know that a bag filled with gas has a lifting power and can move + through the air at an appreciable height. Therefore, a contract to + transport a person in such manner is a good contract, and the conditions + being favorable could undoubtedly be enforced. But the passengers' right + of action for injury would be very limited. + </p> + <p> + No Redress for Purchasers. + </p> + <p> + "In the case of giving warranties on aeroplanes, we have yet to see just + what a court is going to say. It is easy enough for a manufacturer to + guarantee to build a machine of certain dimensions and according to + certain specifications, but when he inserts a clause in the contract to + the effect that the machine will raise itself from the surface of the + earth, defy the laws of gravity, and soar in the heavens at the will of + the aviator, he is to say the least contracting to perform a miracle. + </p> + <p> + "Until aeroplanes have been made and accepted as practical, no court will + force a manufacturer to turn out a machine guaranteed to fly. So + purchasers can well remember that if their machines refuse to fly they + have no redress against the maker, for he can always say, 'The industry is + still in its experimental stage.' In contracting for an engine no builder + will guarantee that the particular engine will successfully operate the + aeroplane. In fact he could never be forced to live up to such an + agreement, should he agree to a stipulation of that sort. The best any + engine maker will guarantee is to build an engine according to + specifications." + </p> + <p> + <a name="link2HCH0020" id="link2HCH0020"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XX. SOARING FLIGHT. + </h2> + <h3> + By Octave Chanute. + </h3> + <p> + <a href="#linknote-5" name="linknoteref-5" id="linknoteref-5"><small>5</small></a> + There is a wonderful performance daily exhibited in southern climes and + occasionally seen in northerly latitudes in summer, which has never been + thoroughly explained. It is the soaring or sailing flight of certain + varieties of large birds who transport themselves on rigid, unflapping + wings in any desired direction; who in winds of 6 to 20 miles per hour, + circle, rise, advance, return and remain aloft for hours without a beat of + wing, save for getting under way or convenience in various maneuvers. They + appear to obtain from the wind alone all the necessary energy, even to + advancing dead against that wind. This feat is so much opposed to our + general ideas of physics that those who have not seen it sometimes deny + its actuality, and those who have only occasionally witnessed it + subsequently doubt the evidence of their own eyes. Others, who have seen + the exceptional performances, speculate on various explanations, but the + majority give it up as a sort of "negative gravity." + </p> + <p> + Soaring Power of Birds. + </p> + <p> + The writer of this paper published in the "Aeronautical Annual" for 1896 + and 1897 an article upon the sailing flight of birds, in which he gave a + list of the authors who had described such flight or had advanced theories + for its explanation, and he passed these in review. He also described his + own observations and submitted some computations to account for the + observed facts. These computations were correct as far as they went, but + they were scanty. It was, for instance, shown convincingly by analysis + that a gull weighing 2.188 pounds, with a total supporting surface of + 2.015 square feet, a maximum body cross-section of 0.126 square feet and a + maximum cross-section of wing edges of 0.098 square feet, patrolling on + rigid wings (soaring) on the weather side of a steamer and maintaining an + upward angle or attitude of 5 degrees to 7 degrees above the horizon, in a + wind blowing 12.78 miles an hour, which was deflected upward 10 degrees to + 20 degrees by the side of the steamer (these all being carefully observed + facts), was perfectly sustained at its own "relative speed" of 17.88 miles + per hour and extracted from the upward trend of the wind sufficient energy + to overcome all the resistances, this energy amounting to 6.44 foot-pounds + per second. + </p> + <p> + Great Power of Gulls. + </p> + <p> + It was shown that the same bird in flapping flight in calm air, with an + attitude or incidence of 3 degrees to 5 degrees above the horizon and a + speed of 20.4 miles an hour was well sustained and expended 5.88 + foot-pounds per second, this being at the rate of 204 pounds sustained per + horsepower. It was stated also that a gull in its observed maneuvers, + rising up from a pile head on unflapping wings, then plunging forward + against the wind and subsequently rising higher than his starting point, + must either time his ascents and descents exactly with the variations in + wind velocities, or must meet a wind billow rotating on a horizontal axis + and come to a poise on its crest, thus availing of an ascending trend. + </p> + <p> + But the observations failed to demonstrate that the variations of the wind + gusts and the movements of the bird were absolutely synchronous, and it + was conjectured that the peculiar shape of the soaring wing of certain + birds, as differentiated from the flapping wing, might, when experimented + upon, hereafter account for the performance. + </p> + <p> + Mystery to be Explained. + </p> + <p> + These computations, however satisfactory they were for the speed of winds + observed, failed to account for the observed spiral soaring of buzzards in + very light winds and the writer was compelled to confess: "Now, this + spiral soaring in steady breezes of 5 to 10 miles per hour which are + apparently horizontal, and through which the bird maintains an average + speed of about 20 miles an hour, is the mystery to be explained. It is not + accounted for, quantitatively, by any of the theories which have been + advanced, and it is the one performance which has led some observers to + claim that it was done through 'aspiration.' i, e., that a bird acted upon + by a current, actually drew forward into that current against its exact + direction of motion." + </p> + <p> + Buzzards Soar in Dead Calm. + </p> + <p> + A still greater mystery was propounded by the few observers who asserted + that they had seen buzzards soaring in a dead calm, maintaining their + elevation and their speed. Among these observers was Mr. E. C. Huffaker, + at one time assistant experimenter for Professor Langley. The writer + believed and said then that he must in some way have been mistaken, yet, + to satisfy himself, he paid several visits to Mr. Huffaker, in Eastern + Tennessee and took along his anemometer. He saw quite a number of buzzards + sailing at a height of 75 to 100 feet in breezes measuring 5 or 6 miles an + hour at the surface of the ground, and once he saw one buzzard soaring + apparently in a dead calm. + </p> + <p> + The writer was fairly baffled. The bird was not simply gliding, utilizing + gravity or acquired momentum, he was actually circling horizontally in + defiance of physics and mathematics. It took two years and a whole series + of further observations to bring those two sciences into accord with the + facts. + </p> + <p> + Results of Close Observations. + </p> + <p> + Curiously enough the key to the performance of circling in a light wind or + a dead calm was not found through the usual way of gathering human + knowledge, i. e., through observations and experiment. These had failed + because I did not know what to look for. The mystery was, in fact, solved + by an eclectic process of conjecture and computation, but once these + computations indicated what observations should be made, the results gave + at once the reasons for the circling of the birds, for their then observed + attitude, and for the necessity of an independent initial sustaining speed + before soaring began. Both Mr. Huffaker and myself verified the data many + times and I made the computations. + </p> + <p> + These observations disclosed several facts: + </p> + <p> + 1st.—That winds blowing five to seventeen miles per hour frequently + had rising trends of 10 degrees to 15 degrees, and that upon occasions + when there seemed to be absolutely no wind, there was often nevertheless a + local rising of the air estimated at a rate of four to eight miles or more + per hour. This was ascertained by watching thistledown, and rising fogs + alongside of trees or hills of known height. Everyone will readily realize + that when walking at the rate of four to eight miles an hour in a dead + calm the "relative wind" is quite inappreciable to the senses and that + such a rising air would not be noticed. + </p> + <p> + 2nd.—That the buzzard, sailing in an apparently dead horizontal + calm, progressed at speeds of fifteen to eighteen miles per hour, as + measured by his shadow on the ground. It was thought that the air was then + possibly rising 8.8 feet per second, or six miles per hour. + </p> + <p> + 3rd.—That when soaring in very light winds the angle of incidence of + the buzzards was negative to the horizon—i. e., that when seen + coming toward the eye, the afternoon light shone on the back instead of on + the breast, as would have been the case had the angle been inclined above + the horizon. + </p> + <p> + 4th.—That the sailing performance only occurred after the bird had + acquired an initial velocity of at least fifteen or eighteen miles per + hour, either by industrious flapping or by descending from a perch. + </p> + <p> + An Interesting Experiment. + </p> + <p> + 5th.—That the whole resistance of a stuffed buzzard, at a negative + angle of 3 degrees in a current of air of 15.52 miles per hour, was 0.27 + pounds. This test was kindly made for the writer by Professor A. F. Zahm + in the "wind tunnel" of the Catholic University at Washington, D. C., who, + moreover, stated that the resistance of a live bird might be less, as the + dried plumage could not be made to lie smooth. + </p> + <p> + This particular buzzard weighed in life 4.25 pounds, the area of his wings + and body was 4.57 square feet, the maximum cross-section of his body was + 0.110 square feet, and that of his wing edges when fully extended was + 0.244 square feet. + </p> + <p> + With these data, it became surprisingly easy to compute the performance + with the coefficients of Lilienthal for various angles of incidence and to + demonstrate how this buzzard could soar horizontally in a dead horizontal + calm, provided that it was not a vertical calm, and that the air was + rising at the rate of four or six miles per hour, the lowest observed, and + quite inappreciable without actual measuring. + </p> + <p> + Some Data on Bird Power. + </p> + <p> + The most difficult case is purposely selected. For if we assume that the + bird has previously acquired an initial minimum speed of seventeen miles + an hour (24.93 feet per second, nearly the lowest measured), and that the + air was rising vertically six miles an hour (8.80 feet per second), then + we have as the trend of the "relative wind" encountered: + </p> +<pre xml:space="preserve"> + 6 + — = 0.353, or the tangent of 19 degrees 26'. + 17 +</pre> + <p> + which brings the case into the category of rising wind effects. But the + bird was observed to have a negative angle to the horizon of about 3 + degrees, as near as could be guessed, so that his angle of incidence to + the "relative wind" was reduced to 16 degrees 26'. + </p> + <p> + The relative speed of his soaring was therefore: + </p> + <p> + Velocity = square root of (17 squared + 6 squared) = 18.03 miles per hour. + </p> + <p> + At this speed, using the Langley co-efficient recently practically + confirmed by the accurate experiments of Mr. Eiffel, the air pressure + would be: + </p> + <p> + 18.03 squared X 0.00327 = 1.063 pounds per square foot. + </p> + <p> + If we apply Lilienthal's co-efficients for an angle of 6 degrees 26', we + have for the force in action: + </p> +<pre xml:space="preserve"> + Normal: 4.57 X 1.063 X 0.912 = 4.42 pounds. + + Tangential: 4.57 X 1.063 X 0.074 = - 0.359 pounds, + which latter, being negative, is a propelling force. +</pre> + <p> + Results Astonish Scientists. + </p> + <p> + Thus we have a bird weighing 4.25 pounds not only thoroughly supported, + but impelled forward by a force of 0.359 pounds, at seventeen miles per + hour, while the experiments of Professor A. F. Zahm showed that the + resistance at 15.52 miles per hour was only 0.27 pounds, + </p> +<pre xml:space="preserve"> + 17 squared + or 0.27 X ———- = 0.324 pounds, at seventeen miles an + 15.52 squared + hour. +</pre> + <p> + These are astonishing results from the data obtained, and they lead to the + inquiry whether the energy of the rising air is sufficient to make up the + losses which occur by reason of the resistance and friction of the bird's + body and wings, which, being rounded, do not encounter air pressures in + proportion to their maximum cross-section. + </p> + <p> + We have no accurate data upon the co-efficients to apply and estimates + made by myself proved to be much smaller than the 0.27 pounds resistance + measured by Professor Zahm, so that we will figure with the latter as + modified. As the speed is seventeen miles per hour, or 24.93 feet per + second, we have for the work: + </p> + <p> + Work done, 0.324 X 24.93 = 8.07 foot pounds per second. + </p> + <p> + Endorsed by Prof. Marvin. + </p> + <p> + Corresponding energy of rising air is not sufficient at four miles per + hour. This amounts to but 2.10 foot pounds per second, but if we assume + that the air was rising at the rate of seven miles per hour (10.26 feet + per second), at which the pressure with the Langley coefficient would be + 0.16 pounds per square foot, we have on 4.57 square feet for energy of + rising air: 4.57 X 0.16 X 10.26 = 7.50 foot pounds per second, which is + seen to be still a little too small, but well within the limits of error, + in view of the hollow shape of the bird's wings, which receive greater + pressure than the flat planes experimented upon by Langley. + </p> + <p> + These computations were chiefly made in January, 1899, and were + communicated to a few friends, who found no fallacy in them, but thought + that few aviators would understand them if published. They were then + submitted to Professor C. F. Marvin of the Weather Bureau, who is well + known as a skillful physicist and mathematician. He wrote that they were, + theoretically, entirely sound and quantitatively, probably, as accurate as + the present state of the measurements of wind pressures permitted. The + writer determined, however, to withhold publication until the feat of + soaring flight had been performed by man, partly because he believed that, + to ensure safety, it would be necessary that the machine should be + equipped with a motor in order to supplement any deficiency in wind force. + </p> + <p> + Conditions Unfavorable for Wrights. + </p> + <p> + The feat would have been attempted in 1902 by Wright brothers if the local + circumstances had been more favorable. They were experimenting on "Kill + Devil Hill," near Kitty Hawk, N. C. This sand hill, about 100 feet high, + is bordered by a smooth beach on the side whence come the sea breezes, but + has marshy ground at the back. Wright brothers were apprehensive that if + they rose on the ascending current of air at the front and began to circle + like the birds, they might be carried by the descending current past the + back of the hill and land in the marsh. Their gliding machine offered no + greater head resistance in proportion than the buzzard, and their gliding + angles of descent are practically as favorable, but the birds performed + higher up in the air than they. + </p> + <p> + Langley's Idea of Aviation. + </p> + <p> + Professor Langley said in concluding his paper upon "The Internal Work of + the Wind": + </p> + <p> + "The final application of these principles to the art of aerodromics + seems, then, to be, that while it is not likely that the perfected + aerodrome will ever be able to dispense altogether with the ability to + rely at intervals on some internal source of power, it will not be + indispensable that this aerodrome of the future shall, in order to go any + distance—even to circumnavigate the globe without alighting—need + to carry a weight of fuel which would enable it to perform this journey + under conditions analogous to those of a steamship, but that the fuel and + weight need only be such as to enable it to take care of itself in + exceptional moments of calm." + </p> + <p> + Now that dynamic flying machines have been evolved and are being brought + under control, it seems to be worth while to make these computations and + the succeeding explanations known, so that some bold man will attempt the + feat of soaring like a bird. The theory underlying the performance in a + rising wind is not new, it has been suggested by Penaud and others, but it + has attracted little attention because the exact data and the maneuvers + required were not known and the feat had not yet been performed by a man. + The puzzle has always been to account for the observed act in very light + winds, and it is hoped that by the present selection of the most difficult + case to explain—i. e., the soaring in a dead horizontal calm—somebody + will attempt the exploit. + </p> + <p> + Requisites for Soaring Flights. + </p> + <p> + The following are deemed to be the requisites and maneuvers to master the + secrets of soaring flight: + </p> + <p> + 1st—Develop a dynamic flying machine weighing about one pound per + square foot of area, with stable equilibrium and under perfect control, + capable of gliding by gravity at angles of one in ten (5 3/4 degrees) in + still air. + </p> + <p> + 2nd.—Select locations where soaring birds abound and occasions where + rising trends of gentle winds are frequent and to be relied on. + </p> + <p> + 3rd.—Obtain an initial velocity of at least 25 feet per second + before attempting to soar. + </p> + <p> + 4th.—So locate the center of gravity that the apparatus shall assume + a negative angle, fore and aft, of about 3 degrees. + </p> + <p> + Calculations show, however, that sufficient propelling force may still + exist at 0 degrees, but disappears entirely at +4 degrees. + </p> + <p> + 5th.—Circle like the bird. Simultaneously with the steering, incline + the apparatus to the side toward which it is desired to turn, so that the + centrifugal force shall be balanced by the centripetal force. The amount + of the required inclination depends upon the speed and on the radius of + the circle swept over. + </p> + <p> + 6th.—Rise spirally like the bird. Steer with the horizontal rudder, + so as to descend slightly when going with the wind and to ascend when + going against the wind. The bird circles over one spot because the rising + trends of wind are generally confined to small areas or local chimneys, as + pointed out by Sir H. Maxim and others. + </p> + <p> + 7th.—Once altitude is gained, progress may be made in any direction + by gliding downward by gravity. + </p> + <p> + The bird's flying apparatus and skill are as yet infinitely superior to + those of man, but there are indications that within a few years the latter + may evolve more accurately proportioned apparatus and obtain absolute + control over it. + </p> + <p> + It is hoped, therefore, that if there be found no radical error in the + above computations, they will carry the conviction that soaring flight is + not inaccessible to man, as it promises great economies of motive power in + favorable localities of rising winds. + </p> + <p> + The writer will be grateful to experts who may point out any mistake + committed in data or calculations, and will furnish additional information + to any aviator who may wish to attempt the feat of soaring. + </p> + <p> + <a name="link2HCH0021" id="link2HCH0021"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XXI. FLYING MACHINES VS. BALLOONS. + </h2> + <p> + While wonderful success has attended the development of the dirigible + (steerable) balloon the most ardent advocates of this form of aerial + navigation admit that it has serious drawbacks. Some of these may be + described as follows: + </p> + <p> + Expense and Other Items. + </p> + <p> + Great Initial Expense.—The modern dirigible balloon costs a fortune. + The Zeppelin, for instance, costs more than $100,000 (these are official + figures). + </p> + <p> + Expense of Inflation.—Gas evaporates rapidly, and a balloon must be + re-inflated, or partially re-inflated, every time it is used. The Zeppelin + holds 460,000 cubic feet of gas which, even at $1 per thousand, would cost + $460. + </p> + <p> + Difficulty of Obtaining Gas.—If a balloon suddenly becomes deflated, + by accident or atmospheric conditions, far from a source of gas supply, it + is practically worthless. Gas must be piped to it, or the balloon carted + to the gas house—an expensive proceeding in either event. + </p> + <p> + Lack of Speed and Control. + </p> + <p> + Lack of Speed.—Under the most favorable conditions the maximum speed + of a balloon is 30 miles an hour. Its great bulk makes the high speed + attained by flying machines impossible. + </p> + <p> + Difficulty of Control.—While the modern dirigible balloon is readily + handled in calm or light winds, its bulk makes it difficult to control in + heavy winds. + </p> + <p> + The Element of Danger.—Numerous balloons have been destroyed by + lightning and similar causes. One of the largest of the Zeppelins was thus + lost at Stuttgart in 1908. + </p> + <p> + Some Balloon Performances. + </p> + <p> + It is only a matter of fairness to state that, under favorable conditions, + some very creditable records have been made with modern balloons, viz: + </p> + <p> + November 23d, 1907, the French dirigible Patrie, travelled 187 miles in 6 + hours and 45 minutes against a light wind. This was a little over 28 miles + an hour. + </p> + <p> + The Clement-Bayard, another French machine, sold to the Russian + government, made a trip of 125 miles at a rate of 27 miles an hour. + </p> + <p> + Zeppelin No. 3, carrying eight passengers, and having a total lifting + capacity of 5,500 pounds of ballast in addition to passengers, weight of + equipment, etc., was tested in October, 1906, and made 67 miles in 2 hours + and 17 minutes, about 30 miles an hour. + </p> + <p> + These are the best balloon trips on record, and show forcefully the + limitations of speed, the greatest being not over 30 miles an hour. + </p> + <p> + Speed of Flying Machines. + </p> + <p> + Opposed to the balloon performances we have flying machine trips (of + authentic records) as follows: + </p> + <p> + Bleriot—monoplane—in 1908—52 miles an hour. + </p> + <p> + Delagrange—June 22, 1908—10 1/2 miles in 16 minutes, + approximately 42 miles an hour. + </p> + <p> + Wrights—October, 1905—the machine was then in its infancy—24 + miles in 38 minutes, approximately 44 miles an hour. On December 31, 1908, + the Wrights made 77 miles in 2 hours and 20 minutes. + </p> + <p> + Lambert, a pupil of the Wrights, and using a Wright biplane, on October + 18, 1909, covered 29.82 miles in 49 minutes and 39 seconds, being at the + rate of 36 miles an hour. This flight was made at a height of 1,312 feet. + </p> + <p> + Latham—October 21, 1909—made a short flight, about 11 minutes, + in the teeth of a 40 mile gale, at Blackpool, Eng. He used an Antoniette + monoplane, and the official report says: "This exhibition of nerve, daring + and ability is unparalled in the history of aviation." + </p> + <p> + Farman—October 20, 1909—was in the air for 1 hour, 32 min., 16 + seconds, travelling 47 miles, 1,184 yards, a duration record for England. + </p> + <p> + Paulhan—January 18, 1901—47 1/2 miles at the rate of 45 miles + an hour, maintaining an altitude of from 1,000 to 2,000 feet. + </p> + <p> + Expense of Producing Gas. + </p> + <p> + Gas is indispensable in the operation of dirigible balloons, and gas is + expensive. Besides this it is not always possible to obtain it in + sufficient quantities even in large cities, as the supply on hand is + generally needed for regular customers. Such as can be had is either water + or coal gas, neither of which is as efficient in lifting power as + hydrogen. + </p> + <p> + Hydrogen is the lightest and consequently the most buoyant of all known + gases. It is secured commercially by treating zinc or iron with dilute + sulphuric or hydrochloric acid. The average cost may be safely placed at + $10 per 1,000 feet so that, to inflate a balloon of the size of the + Zeppelin, holding 460,000 cubic feet, would cost $4,600. + </p> + <p> + Proportions of Materials Required. + </p> + <p> + In making hydrogen gas it is customary to allow 20 per cent for loss + between the generation and the introduction of the gas into the balloon. + Thus, while the formula calls for iron 28 times heavier than the weight of + the hydrogen required, and acid 49 times heavier, the real quantities are + 20 per cent greater. Hydrogen weighs about 0.09 ounce to the cubic foot. + Consequently if we need say 450,000 cubic feet of gas we must have + 2,531.25 pounds in weight. To produce this, allowing for the 20 percent + loss, we must have 35 times its weight in iron, or over 44 tons. Of acid + it would take 60 times the weight of the gas, or nearly 76 tons. + </p> + <p> + In Time of Emergency. + </p> + <p> + These figures are appalling, and under ordinary conditions would be + prohibitive, but there are times when the balloon operator, unable to + obtain water or coal gas, must foot the bills. In military maneuvers, + where the field of operation is fixed, it is possible to furnish supplies + of hydrogen gas in portable cylinders, but on long trips where sudden + leakage or other cause makes descent in an unexpected spot unavoidable, it + becomes a question of making your own hydrogen gas or deserting the + balloon. And when this occurs the balloonist is up against another serious + proposition—can he find the necessary zinc or iron? Can he get the + acid? + </p> + <p> + Balloons for Commercial Use. + </p> + <p> + Despite all this the balloon has its uses. If there is to be such a thing + as aerial navigation in a commercial way—the carrying of freight and + passengers—it will come through the employment of such monster + balloons as Count Zeppelin is building. But even then the carrying + capacity must of necessity be limited. The latest Zeppelin creation, a + monster in size, is 450 feet long, and 42 1/2 feet in diameter. The + dimensions are such as to make all other balloons look like pigmies; even + many ocean-going steamers are much smaller, and yet its passenger capacity + is very small. On its 36-hour flight in May, 1909, the Zeppelin, carried + only eight passengers. The speed, however, was quite respectable, 850 + miles being covered in the 36 hours, a trifle over 23 miles an hour. The + reserve buoyancy, that is the total lifting capacity aside from the weight + of the airship and its equipment, is estimated at three tons. + </p> + <p> + <a name="link2HCH0022" id="link2HCH0022"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XXII. PROBLEMS OF AERIAL FLIGHT. + </h2> + <p> + In a lecture before the Royal Society of Arts, reported in Engineering, F. + W. Lanchester took the position that practical flight was not the abstract + question which some apparently considered it to be, but a problem in + locomotive engineering. The flying machine was a locomotive appliance, + designed not merely to lift a weight, but to transport it elsewhere, a + fact which should be sufficiently obvious. Nevertheless one of the leading + scientific men of the day advocated a type in which this, the main + function of the flying machine, was overlooked. When the machine was + considered as a method of transport, the vertical screw type, or + helicopter, became at once ridiculous. It had, nevertheless, many + advocates who had some vague and ill-defined notion of subsequent motion + through the air after the weight was raised. + </p> + <p> + Helicopter Type Useless. + </p> + <p> + When efficiency of transport was demanded, the helicopter type was + entirely out of court. Almost all of its advocates neglected the effect of + the motion of the machine through the air on the efficiency of the + vertical screws. They either assumed that the motion was so slow as not to + matter, or that a patch of still air accompanied the machine in its + flight. Only one form of this type had any possibility of success. In this + there were two screws running on inclined axles—one on each side of + the weight to be lifted. The action of such inclined screw was curious, + and in a previous lecture he had pointed out that it was almost exactly + the same as that of a bird's wing. In high-speed racing craft such + inclined screws were of necessity often used, but it was at a sacrifice of + their efficiency. In any case the efficiency of the inclined-screw + helicopter could not compare with that of an aeroplane, and that type + might be dismissed from consideration so soon as efficiency became the + ruling factor of the design. + </p> + <p> + Must Compete With Locomotive. + </p> + <p> + To justify itself the aeroplane must compete, in some regard or other, + with other locomotive appliances, performing one or more of the purposes + of locomotion more efficiently than existing systems. It would be no use + unless able to stem air currents, so that its velocity must be greater + than that of the worst winds liable to be encountered. To illustrate the + limitations imposed on the motion of an aeroplane by wind velocity, Mr. + Lanchester gave the diagrams shown in Figs. 1 to 4. The circle in each + case was, he said, described with a radius equal to the speed of the + aeroplane in still air, from a center placed "down-wind" from the + aeroplane by an amount equal to the velocity of the wind. + </p> + <p> + Fig. 1 therefore represented the case in which the air was still, and in + this case the aeroplane represented by <i>A</i> had perfect liberty of + movement in any direction + </p> + <p> + In Fig. 2 the velocity of the wind was half that of the aeroplane, and the + latter could still navigate in any direction, but its speed against the + wind was only one-third of its speed with the wind. + </p> + <p> + In Fig. 3 the velocity of the wind was equal to that of the aeroplane, and + then motion against the wind was impossible; but it could move to any + point of the circle, but not to any point lying to the left of the tangent + <i>A</i> <i>B</i>. Finally, when the wind had a greater speed than the + aeroplane, as in Fig. 4, the machine could move only in directions limited + by the tangents <i>A</i> <i>C</i> and <i>A</i> <i>D</i>. + </p> + <p> + Matter of Fuel Consumption. + </p> + <p> + Taking the case in which the wind had a speed equal to half that of the + aeroplane, Mr. Lanchester said that for a given journey out and home, down + wind and back, the aeroplane would require 30 per cent more fuel than if + the trip were made in still air; while if the journey was made at right + angles to the direction of the wind the fuel needed would be 15 per cent + more than in a calm. This 30 per cent extra was quite a heavy enough + addition to the fuel; and to secure even this figure it was necessary that + the aeroplane should have a speed of twice that of the maximum wind in + which it was desired to operate the machine. Again, as stated in the last + lecture, to insure the automatic stability of the machine it was necessary + that the aeroplane speed should be largely in excess of that of the gusts + of wind liable to be encountered. + </p> + <p> + Eccentricities of the Wind. + </p> + <p> + There was, Mr. Lanchester said, a loose connection between the average + velocity of the wind and the maximum speed of the gusts. When the average + speed of the wind was 40 miles per hour, that of the gusts might be equal + or more. At one moment there might be a calm or the direction of the wind + even reversed, followed, the next moment, by a violent gust. About the + same minimum speed was desirable for security against gusts as was + demanded by other considerations. Sixty miles an hour was the least figure + desirable in an aeroplane, and this should be exceeded as much as + possible. Actually, the Wright machine had a speed of 38 miles per hour, + while Farman's Voisin machine flew at 45 miles per hour. + </p> + <p> + Both machines were extremely sensitive to high winds, and the speaker, in + spite of newspaper reports to the contrary, had never seen either flown in + more than a gentle breeze. The damping out of the oscillations of the + flight path, discussed in the last lecture, increased with the fourth + power of the natural velocity of flight, and rapid damping formed the + easiest, and sometimes the only, defense against dangerous oscillations. A + machine just stable at 35 miles per hour would have reasonably rapid + damping if its speed were increased to 60 miles per hour. + </p> + <p> + Thinks Use Is Limited. + </p> + <p> + It was, the lecturer proceeded, inconceivable that any very extended use + should be made of the aeroplane unless the speed was much greater than + that of the motor car. It might in special cases be of service, apart from + this increase of speed, as in the exploration of countries destitute of + roads, but it would have no general utility. With an automobile averaging + 25 to 35 miles per hour, almost any part of Europe, Russia excepted, was + attainable in a day's journey. A flying machine of but equal speed would + have no advantages, but if the speed could be raised to 90 or 100 miles + per hour, the whole continent of Europe would become a playground, every + part being within a daylight flight of Berlin. Further, some marine craft + now had speeds of 40 miles per hour, and efficiently to follow up and + report movements of such vessels an aeroplane should travel at 60 miles + per hour at least. Hence from all points of view appeared the imperative + desirability of very high velocities of flight. The difficulties of + achievement were, however, great. + </p> + <p> + Weight of Lightest Motors. + </p> + <p> + As shown in the first lecture of his course, the resistance to motion was + nearly independent of the velocity, so that the total work done in + transporting a given weight was nearly constant. Hence the question of + fuel economy was not a bar to high velocities of flight, though should + these become excessive, the body resistance might constitute a large + proportion of the total. The horsepower required varied as the velocity, + so the factor governing the maximum velocity of flight was the horsepower + that could be developed on a given weight. At present the weight per + horsepower of feather-weight motors appeared to range from 2 1/4 pounds up + to 7 pounds per brake horsepower, some actual figures being as follows: + </p> +<pre xml:space="preserve"> + Antoinette........ 5 lbs. + Fiat.............. 3 lbs. + Gnome....... Under 3 lbs. + Metallurgic....... 8 lbs. + Renault........... 7 lbs. + Wright.............6 lbs. +</pre> + <p> + Automobile engines, on the other hand, commonly weighed 12 pounds to 13 + pounds per brake horsepower. + </p> + <p> + For short flights fuel economy was of less importance than a saving in the + weight of the engine. For long flights, however, the case was different. + Thus, if the gasolene consumption was 1/2 pound per horsepower hour, and + the engine weighed 3 pounds per brake horsepower, the fuel needed for a + six-hour flight would weigh as much as the engine, but for half an hour's + flight its weight would be unimportant. + </p> + <p> + Best Means of Propulsion. + </p> + <p> + The best method of propulsion was by the screw, which acting in air was + subject to much the same conditions as obtained in marine work. Its + efficiency depended on its diameter and pitch and on its position, whether + in front of or behind the body propelled. From this theory of dynamic + support, Mr. Lanchester proceeded, the efficiency of each element of a + screw propeller could be represented by curves such as were given in his + first lecture before the society, and from these curves the over-all + efficiency of any proposed propeller could be computed, by mere + inspection, with a fair degree of accuracy. These curves showed that the + tips of long-bladed propellers were inefficient, as was also the portion + of the blade near the root. In actual marine practice the blade from boss + to tip was commonly of such a length that the over-all efficiency was 95 + per cent of that of the most efficient element of it. + </p> + <p> + Advocates Propellers in Rear. + </p> + <p> + From these curves the diameter and appropriate pitch of a screw could be + calculated, and the number of revolutions was then fixed. Thus, for a + speed of 80 feet per second the pitch might come out as 8 feet, in which + case the revolutions would be 600 per minute, which might, however, be too + low for the motor. It was then necessary either to gear down the + propeller, as was done in the Wright machine, or, if it was decided to + drive it direct, to sacrifice some of the efficiency of the propeller. An + analogous case arose in the application of the steam turbine to the + propulsion of cargo boats, a problem as yet unsolved. The propeller should + always be aft, so that it could abstract energy from the wake current, and + also so that its wash was clear of the body propelled. The best possible + efficiency was about 70 per cent, and it was safe to rely upon 66 per + cent. + </p> + <p> + Benefits of Soaring Flight. + </p> + <p> + There was, Mr. Lanchester proceeded, some possibility of the aeronaut + reducing the power needed for transport by his adopting the principle of + soaring flight, as exemplified by some birds. There were, he continued, + two different modes of soaring flight. In the one the bird made use of the + upward current of air often to be found in the neighborhood of steep + vertical cliffs. These cliffs deflected the air upward long before it + actually reached the cliff, a whole region below being thus the seat of an + upward current. Darwin has noted that the condor was only to be found in + the neighborhood of such cliffs. Along the south coast also the gulls made + frequent use of the up currents due to the nearly perpendicular chalk + cliffs along the shore. + </p> + <p> + In the tropics up currents were also caused by temperature differences. + Cumulus clouds, moreover, were nearly always the terminations of such up + currents of heated air, which, on cooling by expansion in the upper + regions, deposited their moisture as fog. These clouds might, perhaps, + prove useful in the future in showing the aeronaut where up currents were + to be found. Another mode of soaring flight was that adopted by the + albatross, which took advantage of the fact that the air moved in + pulsations, into which the bird fitted itself, being thus able to extract + energy from the wind. Whether it would be possible for the aeronaut to + employ a similar method must be left to the future to decide. + </p> + <p> + Main Difficulties in Aviation. + </p> + <p> + In practical flight difficulties arose in starting and in alighting. There + was a lower limit to the speed at which the machine was stable, and it was + inadvisable to leave the ground till this limit was attained. Similarly, + in alighting it was inexpedient to reduce the speed below the limit of + stability. This fact constituted a difficulty in the adoption of high + speeds, since the length of run needed increased in proportion to the + square of the velocity. This drawback could, however, be surmounted by + forming starting and alighting grounds of ample size. He thought it quite + likely in the future that such grounds would be considered as essential to + the flying machine as a seaport was to an ocean-going steamer or as a road + was to the automobile. + </p> + <p> + Requisites of Flying Machine. + </p> + <p> + Flying machines were commonly divided into monoplanes and biplanes, + according as they had one or two supporting surfaces. The distinction was + not, however, fundamental. To get the requisite strength some form of + girder framework was necessary, and it was a mere question of convenience + whether the supporting surface was arranged along both the top and the + bottom of this girder, or along the bottom only. The framework adopted + universally was of wood braced by ties of pianoforte wire, an arrangement + giving the stiffness desired with the least possible weight. Some kind of + chassis was also necessary. + </p> + <p> + <a name="link2HCH0023" id="link2HCH0023"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XXIII. AMATEURS MAY USE WRIGHT PATENTS. + </h2> + <p> + Owing to the fact that the Wright brothers have enjoined a number of + professional aviators from using their system of control, amateurs have + been slow to adopt it. They recognize its merits, and would like to use + the system, but have been apprehensive that it might involve them in + litigation. There is no danger of this, as will be seen by the following + statement made by the Wrights: + </p> + <p> + What Wright Brothers Say. + </p> + <p> + "Any amateur, any professional who is not exhibiting for money, is at + liberty to use our patented devices. We shall be glad to have them do so, + and there will be no interference on our part, by legal action, or + otherwise. The only men we proceed against are those who, without our + permission, without even asking our consent, coolly appropriate the + results of our labors and use them for the purpose of making money. + Curtiss, Delagrange, Voisin, and all the rest of them who have used our + devices have done so in money-making exhibitions. So long as there is any + money to be made by the use of the products of our brains, we propose to + have it ourselves. It is the only way in which we can get any return for + the years of patient work we have given to the problem of aviation. On the + other hand, any man who wants to use these devices for the purpose of + pleasure, or the advancement of science, is welcome to do so, without + money and without price. This is fair enough, is it not?" + </p> + <p> + Basis of the Wright Patents. + </p> + <p> + In a flying machine a normally flat aeroplane having lateral marginal + portions capable of movement to different positions above or below the + normal plane of the body of the aeroplane, such movement being about an + axis transverse to the line of flight, whereby said lateral marginal + portions may be moved to different angles relatively to the normal plane + of the body of the aeroplane, so as to present to the atmosphere different + angles of incidence, and means for so moving said lateral marginal + portions, substantially as described. + </p> + <p> + Application of vertical struts near the ends having flexible joints. + </p> + <p> + Means for simultaneously imparting such movement to said lateral portions + to different angles relatively to each other. + </p> + <p> + Refers to the movement of the lateral portions on the same side to the + same angle. + </p> + <p> + Means for simultaneously moving vertical rudder so as to present to the + wind that side thereof nearest the side of the aeroplane having the + smallest angle of incidence. + </p> + <p> + Lateral stability is obtained by warping the end wings by moving the lever + at the right hand of the operator, connection being made by wires from the + lever to the wing tips. The rudder may also be curved or warped in similar + manner by lever action. + </p> + <p> + Wrights Obtain an Injunction. + </p> + <p> + In January, 1910, Judge Hazel, of the United States Circuit Court, granted + a preliminary injunction restraining the Herring-Curtiss Co., and Glenn H. + Curtiss, from manufacturing, selling, or using for exhibition purposes the + machine known as the Curtiss aeroplane. The injunction was obtained on the + ground that the Curtiss machine is an infringement upon the Wright patents + in the matter of wing warping and rudder control. + </p> + <p> + It is not the purpose of the authors to discuss the subject pro or con. + Such discussion would have no proper place in a volume of this kind. It is + enough to say that Curtiss stoutly insists that his machine is not an + infringement of the Wright patents, although Judge Hazel evidently thinks + differently. + </p> + <p> + What the Judge Said. + </p> + <p> + In granting the preliminary injunction the judge said: + </p> + <p> + "Defendants claim generally that the difference in construction of their + apparatus causes the equilibrium or lateral balance to be maintained and + its aerial movement secured upon an entirely different principle from that + of complainant; the defendants' aeroplanes are curved, firmly attached to + the stanchions and hence are incapable of twisting or turning in any + direction; that the supplementary planes or so-called rudders are secured + to the forward stanchion at the extreme lateral ends of the planes and are + adjusted midway between the upper and lower planes with the margins + extending beyond the edges; that in moving the supplementary planes equal + and uniform angles of incidence are presented as distinguished from + fluctuating angles of incidence. Such claimed functional effects, however, + are strongly contradicted by the expert witness for complainant. + </p> + <p> + Similar to Plan of Wrights. + </p> + <p> + "Upon this contention it is sufficient to say that the affidavits for the + complainant so clearly define the principle of operation of the flying + machines in question that I am reasonably satisfied that there is a + variableness of the angle of incidence in the machine of defendants which + is produced when a supplementary plane on one side is tilted or raised and + the other stimultaneously tilted or lowered. I am also satisfied that the + rear rudder is turned by the operator to the side having the least angle + of incidence and that such turning is done at the time the supplementary + planes are raised or depressed to prevent tilting or upsetting the + machine. On the papers presented I incline to the view, as already + indicated, that the claims of the patent in suit should be broadly + construed; and when given such construction, the elements of the Wright + machine are found in defendants' machine performing the same functional + result. There are dissimilarities in the defendants' structure—changes + of form and strengthening of parts—which may be improvements, but + such dissimilarities seem to me to have no bearing upon the means adopted + to preserve the equilibrium, which means are the equivalent of the claims + in suit and attain an identical result. + </p> + <p> + Variance From Patent Immaterial. + </p> + <p> + "Defendants further contend that the curved or arched surfaces of the + Wright aeroplanes in commercial use are departures from the patent, which + describes 'substantially flat surfaces,' and that such a construction + would be wholly impracticable. The drawing, Fig. 3, however, attached to + the specification, shows a curved line inward of the aeroplane with + straight lateral edges, and considering such drawing with the terminology + of the specification, the slight arching of the surface is not thought a + material departure; at any rate, the patent in issue does not belong to + the class of patents which requires narrowing to the details of + construction." + </p> + <p> + "June Bug" First Infringement. + </p> + <p> + Referring to the matter of priority, the judge said: + </p> + <p> + "Indeed, no one interfered with the rights of the patentees by + constructing machines similar to theirs until in July, 1908, when Curtiss + exhibited a flying machine which he called the 'June Bug.' He was + immediately notified by the patentees that such machine with its movable + surfaces at the tips of wings infringed the patent in suit, and he replied + that he did not intend to publicly exhibit the machine for profit, but + merely was engaged in exhibiting it for scientific purposes as a member of + the Aerial Experiment Association. To this the patentees did not object. + Subsequently, however, the machine, with supplementary planes placed + midway between the upper and lower aeroplanes, was publicly exhibited by + the defendant corporation and used by Curtiss in aerial flights for prizes + and emoluments. It further appears that the defendants now threaten to + continue such use for gain and profit, and to engage in the manufacture + and sale of such infringing machines, thereby becoming an active rival of + complainant in the business of constructing flying machines embodying the + claims in suit, but such use of the infringing machines it is the duty of + this court, on the papers presented, to enjoin. + </p> + <p> + "The requirements in patent causes for the issuance of an injunction + pendente lite—the validity of the patent, general acquiescence by + the public and infringement by the defendants—are so reasonably + clear that I believe if not probable the complainant may succeed at final + hearing, and therefore, status quo should be preserved and a preliminary + injunction granted. + </p> + <p> + "So ordered." + </p> + <p> + Points Claimed By Curtiss. + </p> + <p> + That the Herring-Curtiss Co. will appeal is a certainty. Mr. Emerson R. + Newell, counsel for the company, states its case as follows: + </p> + <p> + "The Curtiss machine has two main supporting surfaces, both of which are + curved * * * and are absolutely rigid at all times and cannot be moved, + warped or distorted in any manner. The front horizontal rudder is used for + the steering up or down, and the rear vertical rudder is used only for + steering to the right or left, in the same manner as a boat is steered by + its rudder. The machine is provided at the rear with a fixed horizontal + surface, which is not present in the machine of the patent, and which has + a distinct advantage in the operation of defendants' machine, as will be + hereafter discussed. + </p> + <p> + Does Not Warp Main Surface. + </p> + <p> + "Defendants' machine does not use the warping of the main supporting + surfaces in restoring the lateral equilibrium, but has two comparatively + small pivoted balancing surfaces or rudders. When one end of the machine + is tipped up or down from the normal, these planes may be thrown in + opposite directions by the operator, and so steer each end of the machine + up or down to its normal level, at which time tension upon them is + released and they are moved back by the pressure of the wind to their + normal position. + </p> + <p> + Rudder Used Only For Steering. + </p> + <p> + "When defendants' balancing surfaces are moved they present equal angles + of incidence to the normal rush of air and equal resistances, at each side + of the machine, and there is therefore no tendency to turn around a + vertical axis as is the case of the machine of the patent, consequently no + reason or necessity for turning the vertical rear rudder in defendants' + machine to counteract any such turning tendency. At any rate, whatever may + be the theories in regard to this matter, the fact is that the operator of + defendants' machine does not at any time turn his vertical rudder to + counteract any turning tendency clue to the side balancing surfaces, but + only uses it to steer the machine the same as a boat is steered." + </p> + <p> + Aero Club Recognizes Wrights. + </p> + <p> + The Aero Club of America has officially recognized the Wright patents. + This course was taken following a conference held April 9th, 1910, + participated in by William Wright and Andrew Freedman, representing the + Wright Co., and the Aero Club's committee, of Philip T. Dodge, W. W. + Miller, L. L. Gillespie, Wm. H. Page and Cortlandt F. Bishop. + </p> + <p> + At this meeting arrangements were made by which the Aero Club recognizes + the Wright patents and will not give its section to any open meet where + the promoters thereof have not secured a license from the Wright Company. + </p> + <p> + The substance of the agreement was that the Aero Club of America + recognizes the rights of the owners of the Wright patents under the + decisions of the Federal courts and refuses to countenance the + infringement of those patents as long as these decisions remain in force. + </p> + <p> + In the meantime, in order to encourage aviation, both at home and abroad, + and in order to permit foreign aviators to take part in aviation contests + in this country it was agreed that the Aero Club of America, as the + American representative of the International Aeronautic Federation, should + approve only such public contests as may be licensed by the Wright Company + and that the Wright Company, on the other hand, should encourage the + holding of open meets or contests where ever approved as aforesaid by the + Aero Club of America by granting licenses to promoters who make + satisfactory arrangements with the company for its compensation for the + use of its patents. At such licensed meet any machine of any make may + participate freely without securing any further license or permit. The + details and terms of all meets will be arranged by the committee having in + charge the interests of both organizations. + </p> + <p> + <a name="link2HCH0024" id="link2HCH0024"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XXIV. HINTS ON PROPELLER CONSTRUCTION. + </h2> + <p> + Every professional aviator has his own ideas as to the design of the + propeller, one of the most important features of flying-machine + construction. While in many instances the propeller, at a casual glance, + may appear to be identical, close inspection will develop the fact that in + nearly every case some individual idea of the designer has been + incorporated. Thus, two propellers of the two-bladed variety, while of the + same general size as to length and width of blade, will vary greatly as to + pitch and "twist" or curvature. + </p> + <p> + What the Designers Seek. + </p> + <p> + Every designer is seeking for the same result—the securing of the + greatest possible thrust, or air displacement, with the least possible + energy. + </p> + <p> + The angles of any screw propeller blade having a uniform or true pitch + change gradually for every increased diameter. In order to give a + reasonably clear explanation, it will be well to review in a primary way + some of the definitions or terms used in connection with and applied to + screw propellers. + </p> + <p> + Terms in General Use. + </p> + <p> + Pitch.—The term "pitch," as applied to a screw propeller, is the + theoretical distance through which it would travel without slip in one + revolution, and as applied to a propeller blade it is the angle at which + the blades are set so as to enable them to travel in a spiral path through + a fixed distance theoretically without slip in one revolution. + </p> + <p> + Pitch speed.—The term "pitch speed" of a screw propeller is the + speed in feet multiplied by the number of revolutions it is caused to make + in one minute of time. If a screw propeller is revolved 600 times per + minute, and if its pitch is 7 ft., then the pitch speed of such a + propeller would be 7x600 revolutions, or 4200 ft. per minute. + </p> + <p> + Uniform pitch.—A true pitch screw propeller is one having its blades + formed in such a manner as to enable all of its useful portions, from the + portion nearest the hub to its outer portion, to travel at a uniform pitch + speed. Or, in other words, the pitch is uniform when the projected area of + the blade is parallel along its full length and at the same time + representing a true sector of a circle. + </p> + <p> + All screw propellers having a pitch equal to their diameters have the same + angle for their blades at their largest diameter. + </p> + <p> + When Pitch Is Not Uniform. + </p> + <p> + A screw propeller not having a uniform pitch, but having the same angle + for all portions of its blades, or some arbitrary angle not a true pitch, + is distinguished from one having a true pitch in the variation of the + pitch speeds that the various portions of its blades are forced to travel + through while traveling at its maximum pitch speed. + </p> + <p> + On this subject Mr. R. W. Jamieson says in Aeronautics: + </p> + <p> + "Take for example an 8-foot screw propeller having an 8-foot pitch at its + largest diameter. If the angle is the same throughout its entire blade + length, then all the porions of its blades approaching the hub from its + outer portion would have a gradually decreasing pitch. The 2-foot portion + would have a 2-foot pitch; the 3-foot portion a 3-foot pitch, and so on to + the 8-foot portion which would have an 8-foot pitch. When this form of + propeller is caused to revolve, say 500 r.p.m., the 8-foot portion would + have a calculated pitch speed of 8 feet by 500 revolutions, or 4,000 feet + per min.; while the 2-foot portion would have a calculated pitch speed of + 500 revolutions by 2 feet, or 1,000 feet per minute. + </p> + <p> + Effect of Non-Uniformity. + </p> + <p> + "Now, as all of the portions of this type of screw propeller must travel + at some pitch speed, which must have for its maximum a pitch speed in feet + below the calculated pitch speed of the largest diameter, it follows that + some portions of its blades would perform useful work while the action of + the other portions would be negative—resisting the forward motion of + the portions having a greater pitch speed. The portions having a pitch + speed below that at which the screw is traveling cease to perform useful + work after their pitch speed has been exceeded by the portions having a + larger diameter and a greater pitch speed. + </p> + <p> + "We might compare the larger and smaller diameter portions of this form of + screw propeller, to two power-driven vessels connected with a line, one + capable of traveling 20 miles per hour, the other 10 miles per hour. It + can be readily understood that the boat capable of traveling 10 miles per + hour would have no useful effect to help the one traveling 20 miles per + hour, as its action would be such as to impose a dead load upon the + latter's progress." + </p> + <p> + The term "slip," as applied to a screw propeller, is the distance between + its calculated pitch speed and the actual distance it travels through + under load, depending upon the efficiency and proportion of its blades and + the amount of load it has to carry. + </p> + <p> + The action of a screw propeller while performing useful work might be + compared to a nut traveling on a threaded bolt; little resistance is + offered to its forward motion while it spins freely without load, but give + it a load to carry; then it will take more power to keep up its speed; if + too great a load is applied the thread will strip, and so it is with a + screw propeller gliding spirally on the air. A propeller traveling without + load on to new air might be compared to the nut traveling freely on the + bolt. It would consume but little power and it would travel at nearly its + calculated pitch speed, but give it work to do and then it will take power + to drive it. + </p> + <p> + There is a reaction caused from the propeller projecting air backward when + it slips, which, together with the supporting effect of the blades, + combine to produce useful work or pull on the object to be carried. + </p> + <p> + A screw propeller working under load approaches more closely to its + maximum efficiency as it carries its load with a minimum amount of slip, + or nearing its calculated pitch speed. + </p> + <p> + Why Blades Are Curved. + </p> + <p> + It has been pointed out by experiment that certain forms of curved + surfaces as applied to aeroplanes will lift more per horse power, per unit + of square foot, while on the other hand it has been shown that a flat + surface will lift more per horse power, but requires more area of surface + to do it. + </p> + <p> + As a true pitch screw propeller is virtually a rotating aeroplane, a + curved surface may be advantageously employed when the limit of size + prevents using large plane surfaces for the blades. + </p> + <p> + Care should be exercised in keeping the chord of any curve to be used for + the blades at the proper pitch angle, and in all cases propeller blades + should be made rigid so as to preserve the true angle and not be distorted + by centrifugal force or from any other cause, as flexibility will + seriously affect their pitch speed and otherwise affect their efficiency. + </p> + <p> + How to Determine Angle. + </p> + <p> + To find the angle for the proper pitch at any point in the diameter of a + propeller, determine the circumference by multiplying the diameter by + 3.1416, which represent by drawing a line to scale in feet. At the end of + this line draw another line to represent the desired pitch in feet. Then + draw a line from the point representing the desired pitch in feet to the + beginning of the circumference line. For example: + </p> + <p> + If the propeller to be laid out is 7 feet in diameter, and is to have a + 7-foot pitch, the circumference will be 21.99 feet. Draw a diagram + representing the circumference line and pitch in feet. If this diagram is + wrapped around a cylinder the angle line will represent a true thread 7 + feet in diameter and 7 feet long, and the angle of the thread will be 17 + 3/4 degrees. + </p> + <p> + Relation of Diameter to Circumference. + </p> + <p> + Since the areas of circles decrease as the diameter lessens, it follows + that if a propeller is to travel at a uniform pitch speed, the volume of + its blade displacement should decrease as its diameter becomes less, so as + to occupy a corresponding relation to the circumferences of larger + diameters, and at the same time the projected area of the blade must be + parallel along its full length and should represent a true sector of a + circle. + </p> + <p> + Let us suppose a 7-foot circle to be divided into 20 sectors, one of which + represents a propeller blade. If the pitch is to be 7 feet, then the + greatest depth of the angle would be 1/20 part of the pitch, or 4 2/10 + inch. If the line representing the greatest depth of the angle is kept the + same width as it approaches the hub, the pitch will be uniform. If the + blade is set at an angle so its projected area is 1/20 part of the pitch, + and if it is moved through 20 divisions for one revolution, it would have + a travel of 7 feet. + </p> + <p> + <a name="link2HCH0025" id="link2HCH0025"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XXV. NEW MOTORS AND DEVICES. + </h2> + <p> + Since the first edition of this book was printed, early in 1910, there has + been a remarkable advance in the construction of aeroplane motors, which + has resulted in a wonderful decrease in the amount of surface area from + that formerly required. Marked gain in lightness and speed of the motor + has enabled aviators to get along, in some instances, with one-quarter of + the plane supporting area previously used. The first Wright biplane, + propelled by a motor of 25 h.p., productive of a fair average speed of 30 + miles an hour, had a plane surface of 538 square feet. Now, by using a + specially designed motor of 65 h. p., capable of developing a speed of + from 70 to 80 miles an hour, the Wrights are enabled to successfully + navigate a machine the plane area of which is about 130 square feet. This + apparatus is intended to carry only one person (the operator). At Belmont + Park, N. Y., the Wrights demonstrated that the small-surfaced biplane is + much faster, easier to manage in the hands of a skilled manipulator, and a + better altitude climber than the large and cumbersome machines with 538 + square feet of surface heretofore used by them. + </p> + <p> + In this may be found a practical illustration of the principle that + increased speed permits of a reduction in plane area in mathematical ratio + to the gain in speed. The faster any object can be made to move through + the air, the less will be the supporting surface required to sustain a + given weight. But, there is a limit beyond which the plane surface cannot + be reduced with safety. Regard must always be had to the securing of an + ample sustaining surface so that in case of motor stoppage there will be + sufficient buoyancy to enable the operator to descend safely. + </p> + <p> + The baby Wright used at the Belmont Park (N. Y.) aviation meet in the fall + of 1910, had a plane length of 19 feet 6 inches, and an extreme breadth of + 21 feet 6 inches, with a total surface area of 146 square feet. It was + equipped with a new Wright 8-cylinder motor of 60 h. p., and two Wright + propellers of 8 feet 6 inches diameter and 500 r. p. m. It was easily the + fastest machine at the meet. After the tests, Wilbur Wright said: + </p> + <p> + "It is our intention to put together a machine with specially designed + propellers, specially designed gears and a motor which will give us 65 + horsepower at least. We will then be able, after some experimental work we + are doing now, to send forth a machine that will make a new speed record." + </p> + <p> + In the new Wright machines the front elevating planes for up-and-down + control have been eliminated, and the movements of the apparatus are now + regulated solely by the rear, or "tail" control. + </p> + <p> + A Powerful Light Motor. + </p> + <p> + Another successful American aviation motor is the aeromotor, manufactured + by the Detroit Aeronautic Construction. Aeromotors are made in four models + as follows: + </p> + <p> + Model 1.—4-cylinder, 30-40 h. p., weight 200 pounds. + </p> + <p> + Model 2.—4-cylinder, (larger stroke and bore) 40-50 h. p., weight + 225 pounds. + </p> + <p> + Model 3.—6-cylinder. 50-60 h. p., weight 210 pounds. + </p> + <p> + Model 4.—6-cylinder, 60-75 h. p., weight 275 pounds. + </p> + <p> + This motor is of the 4-cycle, vertical, water-cooled type. Roberts + Aviation Motor. + </p> + <p> + One of the successful aviation motors of American make, is that produced + by the Roberts Motor Co., of Sandusky, Ohio. It is designed by E. W. + Roberts, M. E., who was formerly chief assistant and designer for Sir + Hiram Maxim, when the latter was making his celebrated aeronautical + experiments in England in 1894-95. This motor is made in both the 4- and + 6-cylinder forms. The 4-cylinder motor weighs complete with Bosch magneto + and carbureter 165 pounds, and will develop 40 actual brake h. p. at 1,000 + r. p. m., 46 h. p. at 1,200 and 52 h. p. at 1,400. The 6-cylinder weighs + 220 pounds and will develop 60 actual brake h. p. at 1,000 r. p. m., 69 h. + p. at 1,200 and 78 h. p. at 1,500. + </p> + <p> + Extreme lightness has been secured by doing away with all superfluous + parts, rather than by a shaving down of materials to a dangerous thinness. + For example, there is neither an intake or exhaust manifold on the motor. + The distributing valve forms a part of the crankcase as does the water + intake, and the gear pump. Magnalium takes the place of aluminum in the + crankcase, because it is not only lighter but stronger and can be cast + very thin. The crankshaft is 2 1/2-inch diameter with a 2 1/4-inch hole, + and while it would be strong enough in ordinary 40 per cent carbon steel + it is made of steel twice the strength of that customarily employed. + Similar care has been exercised on other parts and the result is a motor + weighing 4 pounds per h. p. + </p> + <p> + The Rinek Motor. + </p> + <p> + The Rinek aviation motor, constructed by the Rinek Aero Mfg. Co., of + Easton, Pa., is another that is meeting with favor among aviators. Type + B-8 is an 8-cylinder motor, the cylinders being set at right angles, on a + V-shaped crank case. It is water cooled, develops 50-60 h. p., the minimum + at 1,220 r. p. m., and weighs 280 pounds with all accessories. Type B-4, a + 4-cylinder motor, develops 30 h. p. at 1,800 r. p. m., and weighs 130 + pounds complete. The cylinders in both motors are made of cast iron with + copper water jackets. + </p> + <p> + The Overhead Camshaft Boulevard. + </p> + <p> + The overhead camshaft Boulevard is still another form of aviation motor + which has been favorably received. This is the product of the Boulevard + Engine Co., of St. Louis. It is made with 4 and 8 cylinders. The former + develops 30-35 h. p. at 1,200 r. p. m., and weighs 130 pounds. The + 8-cylinder motor gives 60-70 h. p. at 1,200 r. p. m., and weighs 200 + pounds. Simplicity of construction is the main feature of this motor, + especially in the manipulation of the valves. + </p> + <p> + <a name="link2HCH0026" id="link2HCH0026"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XXVI. MONOPLANES, TRIPLANES, MULTIPLANES. + </h2> + <p> + Until recently, American aviators had not given serious attention to any + form of flying machines aside from biplanes. Of the twenty-one monoplanes + competing at the International meet at Belmont Park, N. Y., in November, + 1910, only three makes were handled by Americans. Moissant and Drexel + navigated Bleriot machines, Harkness an Antoinette, and Glenn Curtiss a + single decker of his own construction. On the other hand the various + foreign aviators who took part in the meet unhesitatingly gave preference + to monoplanes. + </p> + <p> + Whatever may have been the cause of this seeming prejudice against the + monoplane on the part of American air sailors, it is slowly being + overcome. When a man like Curtiss, who has attained great success with + biplanes, gives serious attention to the monoplane form of construction + and goes so far as to build and successfully operate a single surface + machine, it may be taken for granted that the monoplane is a fixture in + this country. + </p> + <p> + Dimensions of Monoplanes. + </p> + <p> + The makes, dimensions and equipment of the various monoplanes used at + Belmont Park are as follows: + </p> + <p> + Bleriot—(Moissant, operator)—plane length 23 feet, extreme + breadth 28 feet, surface area 160 square feet, 7-cylinder, 50 h. p. Gnome + engine, Chauviere propeller, 7 feet 6 inches diameter, 1,200 r. p. m. + </p> + <p> + Bleriot—(Drexel, operator)—exactly the same as Moissant's + machine. + </p> + <p> + Antoinette—(Harkness, operator)—plane length 42 feet, extreme + breadth 46 feet, surface area 377 square feet, Emerson 6-cylinder, 50 h. + p. motor, Antoinette propeller, 7 feet 6 inches diameter, 1,200 r. p. m. + </p> + <p> + Curtiss—(Glenn H. Curtiss, operator)—plane length 25 feet, + extreme breadth 26 feet, surface area 130 square feet, Curtiss 8-cylinder, + 60 h. p. motor, Paragon propeller, 7 feet in diameter, 1,200 r. p. m. + </p> + <p> + With one exception Curtiss had the smallest machine of any of those + entering into competition. The smallest was La Demoiselle, made by + Santos-Dumont, the proportions of which were: plane length 20 feet, + extreme breadth 18 feet, surface area 100 square feet, Clement-Bayard + 2-cylinder, 30 h. p. motor, Chauviere propeller, 6 feet 6 inches in + diameter, 1,100 r. p. m. + </p> + <p> + Winnings Made with Monoplanes. + </p> + <p> + Operators of monoplanes won a fair share of the cash prizes. They won + $30,283 out of a total of $63,250, to say nothing about Grahame-White's + winnings. The latter won $13,600, but part of his winning flights were + made in a Bleriot monoplane, and part in a Farman machine. Aside from + Grahame-White the winnings were divided as follows: Moissant (Bleriot) + $13,350; Latham (Antoinette) $8,183; Aubrun (Bleriot) $2,400; De Lesseps + (Bleriot) $2,300; Drexel (Bleriot) $1,700; Radley (Bleriot) $1,300; Simon + (Bleriot) $750; Andemars (Clement-Bayard) $100; Barrier (Bleriot) $100. + </p> + <p> + Out of a total of $30,283, operators of Bleriot machines won $21,900, + again omitting Grahame-White's share. If the winnings with monoplane and + biplane could be divided so as to show the amount won with each type of + machine the credit side of the Bleriot account would be materially + enlarged. + </p> + <p> + The Most Popular Monoplanes. + </p> + <p> + While the number of successful monoplanes is increasing rapidly, and there + is some feature of advantage in nearly all the new makes, interest centers + chiefly in the Santos-Dumont, Antoinette and Bleriot machines. This is + because more has been accomplished with them than with any of the others, + possibly because they have had greater opportunities. + </p> + <p> + For the guidance of those who may wish to build a machine of the monoplane + type after the Santos-Dumont or Bleriot models, the following details will + be found useful. + </p> + <p> + Santos-Dumont—The latest production of this maker is called the "No. + 20 Baby." It is of 18 feet spread, and 20 feet over all in depth. It + stands 4 feet 2 inches in height, not counting the propeller. When this + latter is in a vertical position the extreme height of the machine is 7 + feet 5 inches. It is strictly a one-man apparatus. The total surface area + is 115 square feet. The total weight of the monoplane with engine and + propeller is 352 pounds. Santos-Dumont weighs 110 pounds, so the entire + weight carried while in flight is 462 pounds, or about 3.6 pounds per + square foot of surface. + </p> + <p> + Bamboo is used in the construction of the body frame, and also for the + frame of the tail. The body frame consists of three bamboo poles about 2 + inches in diameter at the forward end and tapering to about 1 inch at the + rear. These poles are jointed with brass sockets near the rear of the main + plane so they may be taken apart easily for convenience in housing or + transportation. The main plane is built upon four transverse spars of ash, + set at a slight dihedral angle, two being placed on each side of the + central bamboo. These spars are about 2 inches wide by 1 1/8-inch deep for + a few feet each side of the center of the machine, and from there taper + down to an inch in depth at the center bamboo, and at their outer ends, + but the width remains the same throughout their entire length. The planes + are double surfaced with silk and laced above and below the bamboo ribs + which run fore and aft under the main spars and terminate in a forked clip + through which a wire is strung for lacing on the silk. The tail consists + of a horizontal and vertical surface placed on a universal joint about 10 + feet back of the rear edge of the main plane. Both of these surfaces are + flat and consist of a silk covering stretched upon bamboo ribs. The + horizontal surface is 6 feet 5 inches across, and 4 feet 9 inches from + front to back. The vertical surface is of the same width (6 feet 5 inches) + but is only 3 feet 7 inches from front to back. All the details of + construction are shown in the accompanying illustration. + </p> + <p> + Power is furnished by a very light (110 pounds) Darracq motor, of the + double-opposed-cylinder type. It has a bore of 4.118 inches, and stroke of + 4.724 inches, runs at 1,800 r. p. m., and with a 6 1/2-foot propeller + develops a thrust of 242 1/2 pounds when the monoplane is held steady. + </p> + <p> + Bleriot—No. XI, the latest of the Bleriot productions, and the + greatest record maker of the lot, is 28 feet in spread of main plane, and + depth of 6 feet in largest part. This would give a main surface of 168 + square feet, but as the ends of the plane are sharply tapered from the + rear, the actual surface is reduced to 150 square feet. Projecting from + the main frame is an elongated tail (shown in the illustration) which + carries the horizontal and vertical rudders. The former is made in three + sections. The center piece is 6 feet 1 inch in spread, and 2 feet 10 + inches in depth, containing 17 square feet of surface. The end sections, + which are made movable for warping purposes, are each 2 feet 10 inches + square, the combined surface area in the entire horizontal rudder being 33 + square feet. The vertical rudder contains 4 1/2 square feet of surface, + making the entire supporting area 187 1/2 square feet. + </p> + <p> + From the outer end of the propeller shaft in front to the extreme rear + edge of the vertical rudder, the machine is 25 feet deep. Deducting the + 6-foot depth of the main plane leaves 19 feet as the length of the rudder + beam and rudders. The motor equipment consists of a 3-cylinder, air-cooled + engine of about 30 h. p. placed at the front end of the body frame, and + carrying on its crankshaft a two-bladed propeller 6 feet 8 inches in + diameter. The engine speed is about 1,250 r. p. m. at which the propeller + develops a thrust of over 200 pounds. + </p> + <p> + The Bleriot XI complete weighs 484 pounds, and with operator and fuel + supply ready for a 25- or 30-mile flight, 715 pounds. One peculiarity of + the Bleriot construction is that, while the ribs of the main plane are + curved, there is no preliminary bending of the pieces as in other forms of + construction. Bleriot has his rib pieces cut a little longer than required + and, by springing them into place, secures the necessary curvature. A good + view of the Bleriot plane framework is given on page 63. + </p> + <p> + Combined Triplane and Biplane. + </p> + <p> + At Norwich, Conn., the Stebbins-Geynet Co., after several years of + experiment, has begun the manufacture of a combination triplane and + biplane machine. The center plane, which is located about midway between + the upper and lower surfaces, is made removable. The change from triplane + to biplane, or vice versa, may be readily made in a few minutes. The + constructors claim for this type of air craft a large supporting surface + area with the minimum of dimensions in planes. Although this machine has + only 24-foot spread and is only 26 feet over all, its total amount of + supporting area is 400 square feet; weight, 600 pounds in flying order, + and lifting capacity approximately 700 pounds more. + </p> + <p> + The frame is made entirely of a selected grade of Oregon spruce, finished + down to a smooth surface and varnished. All struts are fish-shaped and set + in aluminum sockets, which are bolted to top and lower beams with special + strong bolts of small diameter. The middle plane is set inside the six + uprights and held in place by aluminum castings. A flexible twisted + seven-strand wire cable and Stebbins-Geynet turnbuckles are used for + trussing. + </p> + <p> + The top plane is in three sections, laced together. It has a 24-foot + spread and is 7 feet in depth. The middle plane is in two sections each of + 7 1/2 feet spread and 6 feet in depth. The center ends of the middle plane + sections do not come within 5 feet of joining, this open space being left + for the engine. The bottom plane is of 16 feet spread and 5 feet in depth. + It will thus be seen that the planes overhang one another in depth, the + bottom one being the smallest in this respect. The planes are set at an + angle of 9 degrees, and there is a clear space of 3 1/2 feet between each, + making the total distance from the bottom to the top plane a trifle over 7 + feet. The total supporting surface in the main planes is 350 square feet. + By arranging the three plane surfaces at an angle as described and varying + their size, the greatest amount of lifting area is secured above the + center of gravity, and the greatest weight carried below. + </p> + <p> + The ribs are made of laminated spruce, finished down to 1/2x3/4-inch cross + section dimensions, with a curvature of about 1 in 20, and fastened to the + beams with special aluminum castings. Number 2 Naiad aeroplane cloth is + used in covering the planes, with pockets sewn in for the ribs. + </p> + <p> + Two combination elevating rudders are set up well in front, each having 18 + square feet of supporting area. These rudders are arranged to work in + unison, independently, or in opposite directions. In the Model B machine, + there are also two small rear elevating rudders, which work in unison with + the front rudders. One vertical rudder of 10 square feet is suspended in + the rear of a small stationary horizontal plane in Model A, while the + vertical rudder on Model B is only 6 square feet in size. The elevating + rudders are arranged so as to act as stabilizing planes when the machine + is in flight. The wing tips are held in place with a special two-piece + casting which forms a hinge, and makes a quick detachable joint. Wing tips + are also used in balancing. + </p> + <p> + Model A is equipped with a Cameron 25-30 h. p., 4-cylinder, air-cooled + motor. On Model B a Holmes rotary 7-cylinder motor of 4x4-inch bore and + stroke is used. + </p> + <p> + Positive control is secured by use of the Stebbins-Geynet "auto-control" + system. A pull or push movement operates the elevating rudders, while the + balancing is done by means of side movements or slight turns. The rear + vertical rudder is manipulated by means of a foot lever. + </p> + <p> + New Cody Biplane. + </p> + <p> + Among the comparatively new biplanes is one constructed by Willard F. + Cody, of London, Eng., the principal distinctive feature of which is an + automatic control which works independently of the hand levers. For the + other control a long lever carrying a steering wheel furnishes all the + necessary control movements, there being no footwork at all. The lever is + universally jointed and when moved fore and aft operates the two ailerons + as if they were one; when the shaft is rotated it moves the tail as a + whole. The horizontal tail component is immovable. When the lever is moved + from side to side it works not only the ailerons and the independent + elevators, but also through a peculiar arrangement, the vertical rear + rudder as well. + </p> + <p> + The spread of the planes is 46 feet 6 inches and the width 6 feet 6 + inches. The ailerons jut out 1 foot 6 inches on each side of the machine + and are 13 feet 6 inches long. The cross-shaped tail is supported by an + outrigger composed of two long bamboos and of this the vertical plane is 9 + feet by 4 feet, while the horizontal plane is 8 feet by 4 feet. The + over-all length of the machine is 36 feet. The lifting surface is 857 + square feet. It will weigh, with a pilot, 1,450 pounds. The distance + between the main planes is 8 feet 6 inches, which is a rather notable + feature in this flyer. + </p> + <p> + The propeller has a diameter of 11 feet and 2 inches with a 13-foot 6-inch + pitch; it is driven at 560 revolutions by a chain, and the gear reduction + between the chain and propeller shaft is two to one. + </p> + <p> + The machine from elevator to tail plane bristles in original points. The + hump in the ribs has been cut away entirely, so that although the plane is + double surfaced, the surfaces are closest together at a point which + approximates the center of pressure. The plane is practically of two + stream-line forms, of which one is the continuation of the other. This + construction, claims the inventor, will give increased lift, and decreased + head resistance. The trials substantiate this, as the angle of incidence + in flying is only about one in twenty-six. + </p> + <p> + The ribs in the main planes are made of strips of silver spruce one-half + by one-half inch, while those in the ailerons are solid and one-fourth + inch thick. In the main planes the fabric is held down with thin wooden + fillets. Cody's planes are noted for their neatness, rigidity and + smoothness. Pegamoid fabric is used throughout. + </p> + <p> + Pressey Automatic Control. + </p> + <p> + Another ingenious system of automatic control has been perfected by Dr. J. + B. Pressey, of Newport News, Va. The aeroplane is equipped with a manually + operated, vertical rudder, (3), at the stern, and a horizontal, manually + operated, front control, (4), in front. At the ends of the main plane, and + about midway between the upper and lower sections thereof, there are + supplemental planes, (5). + </p> + <p> + In connection with these supplemental planes (5), there is employed a + gravity influenced weight, the aviator in his seat, for holding them in a + horizontal, or substantially horizontal, position when the main plane is + traveling on an even keel; and for causing them to tip when the main plane + dips laterally, to port or starboard, the planes (5) having a lifting + effect upon the depressed end of the main plane, and a depressing effect + upon the lifted end of the main plane, so as to correct such lateral dip + of the main plane, and restore it to an even keel. To the forward, upper + edge of planes (5) connection is made by means of rod (13) to one arm of a + bellcrank lever, (14) the latter being pivotally mounted upon a fore and + aft pin (15), supported from the main plane; and the other arms of the + port and starboard bellcrank levers (16), are connected by rod (17), which + has an eye (18), for receiving the segmental rod (19), secured to and + projecting from cross bar on seat supporting yoke (7). When, therefore, + the main plane tips downwardly on the starboard side, the rod (17) will be + moved bodily to starboard, and the starboard balancing plane (5) will be + inclined so as to raise its forward edge and depress its rear edge, while, + at the same time, the port balancing plane (5), will be inclined so as to + depress its forward edge, and raise its rear edge, thereby causing the + starboard balancing plane to exert a lifting effect, and the port + balancing plane to exert a depressing effect upon the main plane, with the + result of restoring the main plane to an even keel, at which time the + balancing planes (5), will have resumed their normal, horizontal position. + </p> + <p> + When the main plane dips downwardly on the port side, a reverse action + takes place, with the like result of restoring the main plane to an even + keel. In order to correct forward and aft dip of the main plane, fore and + aft balancing planes (20) and (23) are provided. These planes are carried + by transverse rock shafts, which may be pivotally mounted in any suitable + way, upon structures carried by main plane. In the present instance, the + forward balancing plane is pivotally mounted in extensions (21) of the + frame (22) which carries the forward, manually operated, horizontal + ascending and descending plane + </p> + <p> + It is absolutely necessary, in making a turn with an aeroplane, if that + turn is to be made in safety, that the main plane shall be inclined, or + "banked," to a degree proportional to the radius of the curve and to the + speed of the aeroplane. Each different curve, at the same speed, demands a + different inclination, as is also demanded by each variation in speed in + rounding like curves. This invention gives the desired result with + absolute certainty. + </p> + <p> + The Sellers' Multiplane. + </p> + <p> + Another innovation is a multiplane, or four-surfaced machine, built and + operated by M. B. Sellers, formerly of Grahn, Ky., but now located at + Norwood, Ga. Aside from the use of four sustaining surfaces, the novelty + in the Sellers machine lies in the fact that it is operated successfully + with an 8 h. p. motor, which is the smallest yet used in actual flight. In + describing his work, Mr. Sellers says his purpose has been to develop the + efficiency of the surfaces to a point where flight may be obtained with + the minimum of power and, judging by the results accomplished, he has + succeeded. In a letter written to the authors of this book, Mr. Sellers + says: + </p> + <p> + "I dislike having my machine called a quadruplane, because the number of + planes is immaterial; the distinctive feature being the arrangement of the + planes in steps; a better name would be step aeroplane, or step plane. + </p> + <p> + "The machine as patented, comprises two or more planes arranged in step + form, the highest being in front. The machine I am now using has four + planes 3 ft. x 18 ft.; total about 200 square feet; camber (arch) 1 in 16. + </p> + <p> + "The vertical keel is for lateral stability; the rudder for direction. + This is the first machine (so far as I know) to have a combination of + wheels and runners or skids (Oct. 1908). The wheels rise up automatically + when the machine leaves the ground, so that it may alight on the runners. + </p> + <p> + "A Duthirt & Chalmers 2-cylinder opposed, 3 1/8-inch engine was used + first, and several hundred short flights were made. The engine gave four + brake h. p., which was barely sufficient for continued flight. The + aeroplane complete with this engine weighed 78 pounds. The engine now used + is a Bates 3 5/8-inch, 2-cylinder opposed, showing 8 h. p., and apparently + giving plenty of power. The weight of aeroplane with this engine is now + 110 pounds. Owing to poor grounds only short flights have been made, the + longest to date (Dec. 31, 1910) being about 1,000 feet. + </p> + <p> + "In building the present machine, my object was to produce a safe, slow, + light, and small h. p. aeroplane, a purpose which I have accomplished." + </p> + <p> + <a name="link2HCH0027" id="link2HCH0027"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XXVII. 1911 AEROPLANE RECORDS. + </h2> + <h3> + THE WORLD AT LARGE. + </h3> + <p> + Greatest Speed Per Hour, Whatever Length of Flight, Aviator Alone—E. + Nieuport, Mourmelon, France, June 21, Nieuport Machine, 82.72 miles; with + one passenger, E. Nieuport, Moumlelon, France, June 12, Nieuport Machine, + 67.11 miles; with two passengers, E. Nieuport, Mourmelon, France, March 9, + Nieuport Machine, 63.91 miles; with three passengers, G. Busson, Rheims, + France, March 10, Deperdussin Machine, 59.84 miles; with four passengers, + G. Busson, Rheims, France, March 10, Deperdussin Machine, 54.21 miles. + </p> + <p> + Greatest Distance Aviator Alone—G. Fourny, no stops, Buc, France, + September 2, M. Farman Machine, 447.01 miles; E. Helen, three stops, + Etampes, France, September 8, Nieuport Machine, 778.45 miles; with one + passenger, Lieut. Bier, Austria, October 2, Etrich Machine, 155.34 miles; + with two passengers, Lieut. Bier, Austria, October 4, Etrich Machine, + 69.59 miles; with three passengers, G. Busson, Rheims, France, March 10, + Deperdussin Machine, 31.06 miles; with four passengers, G. Busson, Rheims, + France, March 10, Deperdussin Machine, 15.99 miles. + </p> + <p> + Greatest Duration Aviator Alone—G. Fourny, no stops, Buc, France, + September 2, M. Farman Machine, 11 hours, 1 minute, 29 seconds, E. Helen, + three stops, Etampes, France, September 8, Nieuport Machine, 14 hours, 7 + minutes, 50 seconds, 13 hours, 17 minutes net time; with one passenger, + Suvelack, Johannisthal, Germany, December 8, 4 hours, 23 minutes; with two + passengers, T. de W. Milling, Nassau Boulevard, New York, September 26, + Burgess-Wright Machine, 1 hour, 54 minutes, 42 3-5 seconds; with three + passengers, Warchalowski, Wiener-Neustadt, Aust., October 30, 45 minutes, + 46 seconds; with four passengers, G. Busson, Rheims, France, March 10, + Deperdussin Machine, 17 minutes, 28 1-5 seconds. + </p> + <p> + Greatest Altitude Aviator Alone—Garros, St. Malo, France, September + 4, Bleriot Machine, 13,362 feet; with one passenger, Prevost, Courcy, + France, December 2, 9,840 feet; with two passengers, Lieut. Bier, Austria, + Etrich Machine, 4,010 feet. + </p> + <p> + AMERICAN RECORDS. + </p> + <p> + Greatest Speed Per Hour, Whatever Length of Flight, Aviator Alone—A. + Leblanc, Belmont Park, N. Y., October 29, Bleriot Machine, 67.87 miles; + with one passenger, C. Grahame-White, Squantum, Mass., September 4, + Nieuport Machine, 63.23 miles; with two passengers, T. O. M. Sopwith, + Chicago, Ill., August 15, Wright Machine, 34.96 miles. + </p> + <p> + Greatest Distance Aviator Alone—St. Croix Johnstone, Mineola, N. Y., + July 27, Moisant (Bleriot Type) Machine, 176.23 miles. + </p> + <p> + Greatest Duration Aviator Alone—Howard W. Gill, Kinloch, Mo., + October 19, Wright Machine, 4 hours, 16 minutes, 35 seconds; with one + passenger, G. W. Beatty, Chicago, Ill., August 19, Wright Machine, 3 + hours, 42 minutes, 22 1-5 seconds; with two passengers, T. de W. Milling, + Nassau Boulevard, N. Y., September 26, Burgess-Wright Machine, 1 hour, 54 + minutes, 42 3-5 seconds. + </p> + <p> + Greatest Altitude Aviator Alone—L. Beachy, Chicago, Ill., August 20, + Curtiss Machine, 11,642 feet; with one passenger, C. Grahame-White, Nassau + Boulevard, N. Y., September 30, Nieuport Machine, 3,347 feet. + </p> + <p> + Weight Carrying—P. O. Parmelee, Chicago, III., August 19, Wright + Machine, 458 lbs. + </p> + <p> + AVIATION DEVELOPMENT. + </p> + <p> + The wonderful progress made in the science of aviation during the year + 1911 far surpasses any twelve months' advancement recorded. The + advancement has not been confined to any country or continent, since every + part of the world is taking its part in aviation history making. + </p> + <p> + The rapidly increasing interest in aviation has brought forth schools for + the instruction of flying in both the old and new world, and licensed air + pilots before they receive their sanctions from the governing aero clubs + of their country are required to pass an extremely trying examination in + actual flights. Exhibition flights and races were common in all parts of + the world during 1911, and touring aviators visited India, China, Japan, + South Africa, Australia and South America, giving exhibitions and + instruction. + </p> + <p> + Europe was the scene of a number of cross-country races in which entries + ranging from ten to twenty aviators flew from city to city around a given + circuit, which in some instances exceeded 1,000 miles in distance. + Cross-country flights with and without passengers became so common that + those of less than two hours' duration attracted little attention. There + were fewer attempts at high altitude soaring, although the world's record + in this department of aviation was bettered several times. In place of + these high flights, the aviators devoted more attention to speed, duration + and spectacular manoeuvres, which appeared to satisfy the spectators. The + prize money won during 1911 exceeded $1,000,000, but owing to the + increased number of aviators the individual winnings were not as large as + in 1910. + </p> + <p> + It is estimated that within the past twelve months more than 300,000 miles + have been covered in aeroplane flights and more than seven thousand + persons, classed either as aviators or passengers, taken up into the air. + The aeroplane of today ranges through monoplane, biplane, triplane and + even quadraplane, and more than two hundred types of these machines are in + use. + </p> + <p> + Aeroplanes are becoming a factor of international commerce. The records of + the Bureau of Statistics show that more than $50,000 worth of aeroplanes + were imported into, and exported from, the United States in the months of + July, August and September, 1911. The Bureau of Statistics only began the + maintenance of a separate record of this comparatively new article of + commerce with the opening of the fiscal year 1911-12. + </p> + <p> + Two of the prominent developments of 1911 were the introduction of the + hydro-aeroplane and the motorless glider experiments of the Wright + brothers at Killdevil Hills, N. C., where during the two weeks' + experiments numerous flights with and against the wind were made, + culminating in the establishing of a record by Orville Wright on October + 25, 1911, when in a 52-mile per hour blow he reached an elevation of 225 + feet and remained in the air 10 minutes and 34 seconds. The search for the + secret of automatic stability still continues, and though some remarkable + progress has been made the solution has not yet been reached. + </p> + <p> + <a name="link2H_NOTA" id="link2H_NOTA"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + NOTABLE CROSS-COUNTRY FLIGHTS OF 1911. + </h2> + <p> + One of the important features of 1911 in aviation was the rapid increase + in the number and distance of cross-country flights made either for the + purpose of exhibition, testing, instruction or pleasure. Flights between + cities in almost every country of the world became common occurrences. So + great was the number that only those of more than ordinary importance + because of speed, distance or duration are recorded. The flights of Harry + N. Atwood from Boston to Washington and from St. Louis to New York, and C. + P. Rodgers from New York to Los Angeles were the most important events of + the kind in this country. The St Louis to New York flight was a distance + by air route, 1,266 miles. Duration of flight, 12 days. Net flying time, + 28 hours 53 minutes. Average daily flight, 105.5 miles. Average speed, + 43.9 miles per hour. + </p> + <p> + Transcontinental Flight of Calbraith P. Rodgers.—All world records + for cross-country flying were broken during the New York to Los Angeles + flight of Calbraith P. Rodgers, who left Sheepshead Bay, N. Y., on Sunday, + September 17, 1911, and completed his flight to the Pacific Coast on + Sunday, November 5, at Pasadena, Cal. Rodgers flew a Wright biplane, and + during his long trip the machine was repeatedly repaired, so great was the + strain of the long journey in the air. Rodgers is estimated to have + covered 4,231 miles, although the actual route as mapped out was but 4,017 + miles. Elapsed time to Pasadena, Cal., 49 days; actual time in the air, + 4,924 minutes, equivalent to 3 days 10 hours 4 minutes; average speed + approximating 51 miles per hour. Rodgers' longest flight in one day was + from Sanderson to Sierra Blanca, Texas, on October 28, when he covered 231 + miles. On November 12, Rodgers fell at Compton, Cal., and was badly + injured, causing a delay of 28 days. + </p> + <p> + European Circuit Race.—Started from Paris on June 18, 1911. + Distance, 1,073 miles, via Paris to Liege; Liege to Spa to Liege; Liege to + Utrecht, Holland; Utrecht to Brussels, Belgium; Brussels to Roubaix; + Roubaix to Calais; Calais to London; London to Calais and Calais to Paris. + Three aeronauts were killed either at the start or shortly after the race + was in progress. They were Capt. Princetau, M. Le Martin and M. Lendron. + Three others were injured by falls. Seven hundred thousand spectators + witnessed the start from the aviation field at Vincennes, near Paris. + There were more than forty starters, of which eight finished. The winner, + Lieut. Jean Conneau, who flies under the name of "Andre Beaumont," + completed the circuit on July 7; his actual net flying time for the + distance being 58h. 38m. 4-5s. + </p> + <p> + Circuit of England Race—1,010 Miles in Five Sections.— + </p> + <p> + Start, July 22. Finish, July 26. Prize, $50,000. Twenty-eight entries and + eighteen starters. Seventeen finished the first section from Brooklands to + Hendon, a distance of twenty miles. Five reached Edinburgh, the second + section, a distance of 343 miles, and four completed the entire circuit. + </p> + <p> + Paris to Madrid Race.—This race was started at the Paris aviation + held at Issy-les-Moulineaux on Sunday, May 21. There were twenty-one + entrants, and fully 300,000 spectators gathered to witness the initial + flight of the aerial races. The race was divided into three stages as + follows: Paris to Angouleme, 248 miles; Angouleme to St. Sebastian, 208 + miles, and from St. Sebastian to Madrid, 386 miles, a total distance of + 842 miles. After three of the entrants had safely left the field, Aviator + Train lost control of his plane, and in falling struck and killed M. + Berteaux, the French Minister of War, and seriously injured Premier Monis. + The accident caused the withdrawal of all but six of the original + entrants, and of these but one finished. The race called for a flight over + the Pyrenees Mountains, and Vedrines, the winner, had to rise to a height + of more than 7,000 feet to pass the mountain barrier near Somosierra Pass. + Both Vedrines and Gibert, another competitor, were attacked by eagles + during the latter stages of the flight. Vedrines, who started from Paris + on Monday, May 22, finished the long and perilous race at 8:06 a. m. + Friday, May 26. Vedrines net flying time, all controls and enforced stops + subtracted, was 14h. 55m. 18s. The various prizes to the winner aggregated + $30,000. + </p> + <p> + The Paris-Rome-Turin Race.—The conditions of this race called for a + flight between the cities of Paris, Rome and Turin, covering a distance of + 1,300 miles. The aviators were permitted by the rules to alight whenever + and wherever they desired and the time limit was set from May 28 to June + 15. A prize of $100,000 was offered the winner, but the contest was never + finished, as one after another the aviators dropped out until Frey fell + near Roncigilione, France, breaking both arms and legs and unofficially + ending the contest. There were twenty-one entries and twelve actual + starters. + </p> + <p> + International Speed Cup Race.—The third annual international James + Gordon Bennett speed cup race was held at Eastchurch, England, on July 1, + 1911, and for the second time was won by an American aviator, C. T. + Weymann, in a French racing aeroplane. The distance was 150 kilometres + equivalent to 94 miles, and the winner's time of 1h. 11m. 36s. showed an + average speed of 78.77 miles per hour. The first race was held in 1909 and + was won by Glenn Curtiss, who flew the twenty kilometres (12.4 miles) in + 15 minutes 50 2-5 seconds at an average speed of 47 miles per hour. In + 1910 the winner was Grahame-White, who covered 100 kilometres (62 miles) + at Belmont Park, L. I., in 60 minutes 47 3-5 seconds, an average speed of + 61.3 miles per hour. In the 1911 race there were six starters: three from + France, two from Great Britain and one from the United States. + </p> + <p> + Milan to Turin to Milan Race.—This race which was started from + Milan, Italy, on October 29, was restricted to Italian aviators and had + six starters. The distance was approximately 177 miles and won by + Manissero in a Bleriot machine in 3h. 16m. 2 4-5s. + </p> + <p> + New York to Philadelphia Race.—The first intercity aeroplane race + ever held in the United States was started from New York City on August 5, + and finished in Philadelphia the same day. The prize of $5,000 was offered + by a commercial concern with stores in the two cities: Three entrants + competed from the Curtiss Exhibition Company. The distance was + approximately 83 miles and won by L. Beachey in a Curtiss machine in 1h. + 50m. at an average speed of 45 miles per hour. + </p> + <p> + Tri-State Race.—The tri-state race was the feature event of the + Harvard Aviation Society meet held at Squantum, Mass., August 26 to + September 6. It was held Labor Day, September 4, over a course of 174 + miles, from Boston to Nashua to Worcester to Providence to Boston. Four + competitors started, of which two finished, the winner, E. Ovington, in a + Bleriot machine. Ovington's net flying time, 3h. 6m. 22 1-5s. Winner's + prize, $10,000. + </p> + <p> + AEROPLANES AND DIRIGIBLE BALLOONS IN WARFARE. + </p> + <p> + Wonderful progress has been made in the development of the aeroplane in + this country and in Europe since 1903, and within the last two or three + years the leading powers of the world have entered upon extensive tests + and experiments to determine its availability and usefulness in land and + naval warfare. + </p> + <p> + At the present time all the great powers are building or purchasing + aeroplanes on an extensive scale. They have established government schools + for the instruction of their army and navy officers and for experimental + work. So-called "Airship Fleets" have been constructed and placed in + commission as auxiliaries to the armies and navies. The fleets of France + and Germany are about equal and are larger by far than those of any of the + other powers. The length of the dirigibles composing these fleets runs + from 150 to 500 feet; they are equipped with engines of from 50 to 500 + horse-power, with a rate of speed ranging from 20 to 30 miles per hour. + Their approximate range is from 200 to 900 miles; the longest actual run + (made by the Zeppelin II, Germany) is 800 miles. + </p> + <p> + A British naval airship, one of the largest yet built, was completed last + summer. It has cost over $200,000, and it was in course of designing and + construction two years. It is 510 feet long; can carry 22 persons, and has + a lift of 21 tons. + </p> + <p> + The relative value of the dirigible balloon and the aeroplane in actual + war is yet to be determined. The dirigible is considered to be the safer, + yet several large balloons of this class in Germany and France have met + with disaster, involving loss of lives. The capacity of the dirigible for + longer flights and its superior facilities for carrying apparatus and + operators for wireless telegraphy are distinct advantages. + </p> + <p> + There has not yet been much opportunity to test the airship in actual + warfare. The aeroplane has been used by the Italians in Tripoli for + scouting and reconnoitering and is said to have justified expectations. On + several occasions the Italian military aviators followed the movements of + the enemy, in one instance as far as forty miles inland. At the time of + the attack by the Turks a skillful aeroplane reconnaissance revealed the + approach of a large Turkish force, believed to be at the time sixty miles + away in the mountains. + </p> + <p> + Aeroplanes and airships, as they exist today, would doubtless render very + valuable service in a time of war, both over land and water, in scouting, + reconnoitering, carrying dispatches, and as some experts believe, in + locating submarines and mines placed by the enemy in channels of exits + from ports. A "coast aeroplane" could fly out 30 or 40 miles from land, + and rising to a great height, descry any hostile ships on the distant + horizon, observe their number, strength, formation and direction, and + return within two hours with a report to obtain which would require + several swift torpedo-boat destroyers and a much greater time. The + question as to whether it would be practicable to bombard an enemy on land + or sea with explosive bombs dropped or discharged from flying machines or + airships, is one which is much discussed but hardly yet determined. + </p> + <p> + Aeroplanes have been constructed with floats in the place of runners and + several attempts have been made, in some cases successfully, to light with + them on and to rise from the water. Mr. Curtiss did this at San Francisco, + in January, 1911. Attempts have also been made with the aeroplane to + alight on and to take flight from the deck of a warship. Toward the end of + 1910 Aviator Ely flew to land from the cruiser Birmingham, and in January, + 1911, he flew from land and alighted on the cruiser Pennsylvania. But in + these cases special arrangements were made which would be hardly + practicable in a time of actual war. + </p> + <p> + In November, 1911, a test was made at Newport, R. I., by Lieut. Rodgers, + of the navy, of a "hydro-areoplane" as an auxiliary to a battleship. The + idea of the test was to alight alongside of the ship, hoist the machine + aboard, put out to sea and launch the machine again with the use of a + crane. Lieut. Rodgers came down smoothly alongside the Ohio, his machine + was easily drawn aboard with a crane, and the Ohio steamed down to the + open sea, where it was blowing half a gale. But, owing to the misjudgment + of the ship's headway, one of the wings of the machine when it struck the + water after being released from the crane, went under the water and was + snapped off. Lieut. Rodgers was convinced that this method was too risky + and that some other must be devised. + </p> + <p> + <a name="link2HCH0028" id="link2HCH0028"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER XXVIII. GLOSSARY OF AERONAUTICAL TERMS. + </h2> + <p> + Aerodrome.—Literally a machine that runs in the air. Aerofoil.—The + advancing transverse section of an aeroplane. + </p> + <p> + Aeroplane.—A flying machine of the glider pattern, used in + contra-distinction to a dirigible balloon. + </p> + <p> + Aeronaut.—A person who travels in the air. + </p> + <p> + Aerostat.—A machine sustaining weight in the air. A balloon is an + aerostat. + </p> + <p> + Aerostatic.—Pertaining to suspension in the air; the art of aerial + navigation. + </p> + <p> + Ailerons.—Small stabilizing planes attached to the main planes to + assist in preserving equilibrium. + </p> + <p> + Angle of Incidence.—Angle formed by making comparison with a + perpendicular line or body. + </p> + <p> + Angle of Inclination.—Angle at which a flying machine rises. This + angle, like that of incidence, is obtained by comparison with an upright, + or perpendicular line. + </p> + <p> + Auxiliary Planes.—Minor plane surfaces, used in conjunction with the + main planes for stabilizing purposes. + </p> + <p> + Biplane.—A flying-machine of the glider type with two surface + planes. + </p> + <p> + Blade Twist.—The angle of twist or curvature on a propeller blade. + </p> + <p> + Cambered.—Curve or arch in plane, or wing from port to starboard. + </p> + <p> + Chassis.—The under framework of a flying machine; the framework of + the lower plane. + </p> + <p> + Control.—System by which the rudders and stabilizing planes are + manipulated. + </p> + <p> + Dihedral.—Having two sides and set at an angle, like dihedral + planes, or dihedral propeller blades. + </p> + <p> + Dirigible.—Obedient to a rudder; something that may be steered or + directed. + </p> + <p> + Helicopter.—Flying machine the lifting power of which is furnished + by vertical propellers. + </p> + <p> + Lateral Curvature.—Parabolic form in a transverse direction. + </p> + <p> + Lateral Equilibrium or Stability.—Maintenance of the machine on an + even keel transversely. If the lateral equilibrium is perfect the extreme + ends of the machine will be on a dead level. + </p> + <p> + Longitudinal Equilibrium or Stability.—Maintenance of the machine on + an even keel from front to rear. + </p> + <p> + Monoplane.—Flying machine with one supporting, or surface plane. + </p> + <p> + Multiplane.—Flying machine with more than three surface planes. + </p> + <p> + Ornithopter.—Flying machine with movable bird-like wings. + </p> + <p> + Parabolic Curves.—Having the form of a parabola—a conic + section. + </p> + <p> + Pitch of Propeller Blade.—See "Twist." + </p> + <p> + Ribs.—The pieces over which the cloth covering is stretched. + </p> + <p> + Spread.—The distance from end to end of the main surface; the + transverse dimension. + </p> + <p> + Stanchions.—Upright pieces connecting the upper and lower frames. + </p> + <p> + Struts.—The pieces which hold together longitudinally the main frame + beams. + </p> + <p> + Superposed.—Placed one over another. + </p> + <p> + Surface Area.—The amount of cloth-covered supporting surface which + furnishes the sustaining quality. + </p> + <p> + Sustentation.—Suspension in the air. Power of sustentation; the + quality of sustaining a weight in the air. + </p> + <p> + Triplane.—Flying machine with three surface planes. + </p> + <p> + Thrust of Propeller.—Power with which the blades displace the air. + </p> + <p> + Width.—The distance from the front to the rear edge of a flying + machine. + </p> + <p> + Wind Pressure.—The force exerted by the wind when a body is moving + against it. There is always more or less wind pressure, even in a calm. + </p> + <p> + Wing Tips.—The extreme ends of the main surface planes. Sometimes + these are movable parts of the main planes, and sometimes separate + auxiliary planes. + </p> + <p> + <a name="link2H_FOOT" id="link2H_FOOT"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + Footnotes: + </h2> + <p> + <a name="linknote-1" id="linknote-1"> + <!-- Note --></a> + </p> + <p class="foot"> + 1 (<a href="#linknoteref-1">return</a>)<br /> [ Now dead.] + </p> + <p> + <a name="linknote-2" id="linknote-2"> + <!-- Note --></a> + </p> + <p class="foot"> + 2 (<a href="#linknoteref-2">return</a>)<br /> [ Aeronautics.] + </p> + <p> + <a name="linknote-3" id="linknote-3"> + <!-- Note --></a> + </p> + <p class="foot"> + 3 (<a href="#linknoteref-3">return</a>)<br /> [ See Chapter XXV.] + </p> + <p> + <a name="linknote-4" id="linknote-4"> + <!-- Note --></a> + </p> + <p class="foot"> + 4 (<a href="#linknoteref-4">return</a>)<br /> [ The Wrights' new machine + weighs only 900 pounds.] + </p> + <p> + <a name="linknote-5" id="linknote-5"> + <!-- Note --></a> + </p> + <p class="foot"> + 5 (<a href="#linknoteref-5">return</a>)<br /> [ Aeronautics.] + </p> + <p> + <br /><br /> + </p> +<pre xml:space="preserve"> + + + + + +End of the Project Gutenberg EBook of Flying Machines, by +W.J. 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Russell + +Posting Date: July 26, 2008 [EBook #907] +Release Date: May, 1997 + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK FLYING MACHINES *** + + + + +Produced by Charles Keller + + + + + +FLYING MACHINE: CONSTRUCTION AND OPERATION + +By W.J. Jackman and Thos. H. Russell + + +A Practical Book Which Shows, in Illustrations, Working Plans and Text, +How to Build and Navigate the Modern Airship. + +W.J. JACKMAN, M.E., Author of "A B C of the Motorcycle," "Facts for +Motorists," etc. etc. + +and + +THOS. H. RUSSELL, A.M., M.E., Charter Member of the Aero Club of +Illinois, Author of "History of the Automobile," "Motor Boats: +Construction and Operation," etc. etc. + +With Introductory Chapter By Octave Chanute, C.E., President Aero Club +of Illinois + +1912 + + + + +PREFACE. + +This book is written for the guidance of the novice in aviation--the +man who seeks practical information as to the theory, construction and +operation of the modern flying machine. With this object in view the +wording is intentionally plain and non-technical. It contains some +propositions which, so far as satisfying the experts is concerned, might +doubtless be better stated in technical terms, but this would defeat the +main purpose of its preparation. Consequently, while fully aware of its +shortcomings in this respect, the authors have no apologies to make. + +In the stating of a technical proposition so it may be clearly +understood by people not versed in technical matters it becomes +absolutely necessary to use language much different from that which an +expert would employ, and this has been done in this volume. + +No man of ordinary intelligence can read this book without obtaining +a clear, comprehensive knowledge of flying machine construction and +operation. He will learn, not only how to build, equip, and manipulate +an aeroplane in actual flight, but will also gain a thorough +understanding of the principle upon which the suspension in the air of +an object much heavier than the air is made possible. + +This latter feature should make the book of interest even to those who +have no intention of constructing or operating a flying machine. It will +enable them to better understand and appreciate the performances of the +daring men like the Wright brothers, Curtiss, Bleriot, Farman, Paulhan, +Latham, and others, whose bold experiments have made aviation an +actuality. + +For those who wish to engage in the fascinating pastime of construction +and operation it is intended as a reliable, practical guide. + +It may be well to explain that the sub-headings in the articles by Mr. +Chanute were inserted by the authors without his knowledge. The purpose +of this was merely to preserve uniformity in the typography of the book. +This explanation is made in justice to Mr. Chanute. + +THE AUTHORS. + + + + +IN MEMORIAM. + +Octave Chanute, "the father of the modern flying machine," died at his +home in Chicago on November 23, 1910, at the age of 72 years. His last +work in the interest of aviation was to furnish the introductory chapter +to the first edition of this volume, and to render valuable assistance +in the handling of the various subjects. He even made the trip from his +home to the office of the publishers one inclement day last spring, +to look over the proofs of the book and, at his suggestion, several +important changes were made. All this was "a labor of love" on Mr. +Chanute's part. He gave of his time and talents freely because he was +enthusiastic in the cause of aviation, and because he knew the authors +of this book and desired to give them material aid in the preparation of +the work--a favor that was most sincerely appreciated. + + +The authors desire to make acknowledgment of many courtesies in the way +of valuable advice, information, etc., extended by Mr. Octave Chanute, +C. E., Mr. E. L. Jones, Editor of Aeronautics, and the publishers of, +the New England Automobile Journal and Fly. + + + + +CONTENTS + +Chapter + + I. Evolution of the Two-Surface Flying Machine + Introductory Chapter by Octave Chanute, C. E. + II. Theory Development and Use + Origin of the Aeroplane--Developments by Chanute + and the Wrights--Practical Uses and Limits. + III. Mechanical Bird Action + What the Motor Does--Puzzle in Bird Soaring. + IV. Various Forms of Flying Machines + Helicopters, Ornithopters and Aeroplanes-- + Monoplanes, Biplanes and Triplanes. + V. Constructing a Gliding Machine + Plans and Materials Required--Estimate of Cost-- + Sizes and Preparation of Various Parts--Putting the + Parts Together + VI. Learning to Fly + How to Use the Glider--Effect of Body Movements + --Rules for Beginners--Safest Place to Glide. + VII. Putting On the Rudder + Its Construction, Application and Use. + VIII. The Real Flying Machine + Surface Area Required--Proper Size of Frame and + Auxiliaries--Installation of Motor--Cost of + Constructing Machine. + IX. Selection of the Motor + Essential Features--Multiplicity of Cylinders--Power + Required--Kind and Action of Propellers--Placing + of the Motor + X. Proper Dimensions of Machines + Figuring Out the Details--How to Estimate Load + Capacity--Distribution of the Weight--Measurements + of Leading Machines. + XI. Plane and Rudder Control + Various Methods in Use--Wheels and Hand and + Foot Levers + XII. How to Use the Machine + Rules of Leading Aviators--Rising from the Ground + --Reasonable Altitude--Preserving Equilibrium-- + Learning to Steer. + XIII. Peculiarities of Aeroplane Power + Pressure of the Wind--How to Determine Upon + Power--Why Speed Is Required--Bird find Flying + Machine Areas. + XIV. About Wind Currents, Etc. + Uncertainty of Direct Force--Trouble With Gusty + Currents--Why Bird Action Is Imitated. + XV. The Element of Danger + Risk Small Under Proper Conditions--Two Fields + of Safety--Lessons in Recent Accidents. + XVI. Radical Changes Being Made + Results of Recent Experiments--New Dimensions + --Increased Speed--The One Governing Rule. + XVII. Some of the New Designs + Automatic Control of Plane Stability--Inventor + Herring's Devices--Novel Ideas of Students. + XVIII. Demand for Flying Machines + Wonderful Results in a Year--Factories Over- + crowded with Orders. + XIX. Law of the Airship + Rights of Property Owners--Some Legal + Peculiarities--Danger of Trespass. + XX. Soaring Flight + XXI. Flying Machines vs. Balloons + XXII. Problems of Aerial Flight + XXIII. Amateurs May Use Wright Patents + XXIV. Hints on Propeller Construction + XXV. New Motors and Devices + XXVI. Monoplanes, Triplanes, Multiplanes + XXVII. Records of Various Kinds + + + + +FLYING MACHINES: CONSTRUCTION and OPERATION + + + + +CHAPTER I. EVOLUTION OF TWO-SURFACE FLYING MACHINE. + +By Octave Chanute. + + +I am asked to set forth the development of the "two-surface" type of +flying machine which is now used with modifications by Wright Brothers, +Farman, [1] Delagrange, Herring and others. + +This type originated with Mr. F. H. Wenham, who patented it in +England in 1866 (No. 1571), taking out provisional papers only. In the +abridgment of British patent Aeronautical Specifications (1893) it is +described as follows: + +"Two or more aeroplanes are arranged one above the other, and support a +framework or car containing the motive power. The aeroplanes are made of +silk or canvas stretched on a frame by wooden rods or steel ribs. When +manual power is employed the body is placed horizontally, and oars or +propellers are actuated by the arms or legs. + +"A start may be obtained by lowering the legs and running down hill or +the machine may be started from a moving carriage. One or more screw +propellers may be applied for propelling when steam power is employed." + +On June 27, 1866, Mr. Wenham read before the "Aeronautical Society of +Great Britain," then recently organized, the ablest paper ever presented +to that society, and thereby breathed into it a spirit which has +continued to this day. In this paper he described his observations of +birds, discussed the laws governing flight as to the surfaces and power +required both with wings and screws, and he then gave an account of his +own experiments with models and with aeroplanes of sufficient size to +carry the weight of a man. + +Second Wenham Aeroplane. + +His second aeroplane was sixteen feet from tip to tip. A trussed spar at +the bottom carried six superposed bands of thin holland fabric fifteen +inches wide, connected with vertical webs of holland two feet apart, +thus virtually giving a length of wing of ninety-six feet and one +hundred and twenty square feet of supporting surface. The man was placed +horizontally on a base board beneath the spar. This apparatus when tried +in the wind was found to be unmanageable by reason of the fluttering +motions of the fabric, which was insufficiently stiffened with crinoline +steel, but Mr. Wenham pointed out that this in no way invalidated +the principle of the apparatus, which was to obtain large supporting +surfaces without increasing unduly the leverage and consequent weight of +spar required, by simply superposing the surfaces. + +This principle is entirely sound and it is surprising that it is, +to this day, not realized by those aviators who are hankering for +monoplanes. + +Experiments by Stringfellow. + +The next man to test an apparatus with superposed surfaces was Mr. +Stringfellow, who, becoming much impressed with Mr. Wenham's proposal, +produced a largish model at the exhibition of the Aeronautical Society +in 1868. It consisted of three superposed surfaces aggregating 28 square +feet and a tail of 8 square feet more. The weight was under 12 pounds +and it was driven by a central propeller actuated by a steam engine +overestimated at one-third of a horsepower. It ran suspended to a wire +on its trials but failed of free flight, in consequence of defective +equilibrium. This apparatus has since been rebuilt and is now in the +National Museum of the Smithsonian Institution at Washington. Linfield's +Unsuccessful Efforts. + +In 1878 Mr. Linfield tested an apparatus in England consisting of a +cigar-shaped car, to which was attached on each side frames five feet +square, containing each twenty-five superposed planes of stretched and +varnished linen eighteen inches wide, and only two inches apart, thus +reminding one of a Spanish donkey with panniers. The whole weighed two +hundred and forty pounds. This was tested by being mounted on a flat car +behind a locomotive going 40 miles an hour. When towed by a line fifteen +feet long the apparatus rose only a little from the car and exhibited +such unstable equilibrium that the experiment was not renewed. The lift +was only about one-third of what it would have been had the planes been +properly spaced, say their full width apart, instead of one-ninth as +erroneously devised. + +Renard's "Dirigible Parachute." + +In 1889 Commandant Renard, the eminent superintendent of the French +Aeronautical Department, exhibited at the Paris Exposition of that year, +an apparatus experimented with some years before, which he termed a +"dirigible parachute." It consisted of an oviform body to which were +pivoted two upright slats carrying above the body nine long superposed +flat blades spaced about one-third of their width apart. When this +apparatus was properly set at an angle to the longitudinal axis of the +body and dropped from a balloon, it travelled back against the wind for +a considerable distance before alighting. The course could be varied +by a rudder. No practical application seems to have been made of this +device by the French War Department, but Mr. J. P. Holland, the +inventor of the submarine boat which bears his name, proposed in 1893 +an arrangement of pivoted framework attached to the body of a flying +machine which combines the principle of Commandant Renard with the +curved blades experimented with by Mr. Phillips, now to be noticed, with +the addition of lifting screws inserted among the blades. + +Phillips Fails on Stability Problem. + +In 1893 Mr. Horatio Phillips, of England, after some very interesting +experiments with various wing sections, from which he deduced +conclusions as to the shape of maximum lift, tested an apparatus +resembling a Venetian blind which consisted of fifty wooden slats of +peculiar shape, 22 feet long, one and a half inches wide, and two inches +apart, set in ten vertical upright boards. All this was carried upon a +body provided with three wheels. It weighed 420 pounds and was driven +at 40 miles an hour on a wooden sidewalk by a steam engine of nine +horsepower which actuated a two-bladed screw. The lift was satisfactory, +being perhaps 70 pounds per horsepower, but the equilibrium was quite +bad and the experiments were discontinued. They were taken up again in +1904 with a similar apparatus large enough to carry a passenger, but the +longitudinal equilibrium was found to be defective. Then in 1907 a new +machine was tested, in which four sets of frames, carrying similar +sets of slat "sustainers" were inserted, and with this arrangement the +longitudinal stability was found to be very satisfactory. The whole +apparatus, with the operator, weighed 650 pounds. It flew about 200 +yards when driven by a motor of 20 to 22 h.p. at 30 miles an hour, +thus exhibiting a lift of about 32 pounds per h.p., while it will be +remembered that the aeroplane of Wright Brothers exhibits a lifting +capacity of 50 pounds to the h.p. + +Hargrave's Kite Experiments. + +After experimenting with very many models and building no less than +eighteen monoplane flying model machines, actuated by rubber, by +compressed air and by steam, Mr. Lawrence Hargrave, of Sydney, New South +Wales, invented the cellular kite which bears his name and made it known +in a paper contributed to the Chicago Conference on Aerial Navigation +in 1893, describing several varieties. The modern construction is well +known, and consists of two cells, each of superposed surfaces with +vertical side fins, placed one behind the other and connected by a +rod or frame. This flies with great steadiness without a tail. Mr. +Hargrave's idea was to use a team of these kites, below which he +proposed to suspend a motor and propeller from which a line would be +carried to an anchor in the ground. Then by actuating the propeller the +whole apparatus would move forward, pick up the anchor and fly away. He +said: "The next step is clear enough, namely, that a flying machine with +acres of surface can be safely got under way or anchored and hauled to +the ground by means of the string of kites." + +The first tentative experiments did not result well and emphasized the +necessity for a light motor, so that Mr. Hargrave has since been engaged +in developing one, not having convenient access to those which have been +produced by the automobile designers and builders. + +Experiments With Glider Model. + +And here a curious reminiscence may be indulged in. In 1888 the present +writer experimented with a two-cell gliding model, precisely similar to +a Hargrave kite, as will be confirmed by Mr. Herring. It was frequently +tested by launching from the top of a three-story house and glided +downward very steadily in all sorts of breezes, but the angle of descent +was much steeper than that of birds, and the weight sustained per square +foot was less than with single cells, in consequence of the lesser +support afforded by the rear cell, which operated upon air already set +in motion downward by the front cell, so nothing more was done with +it, for it never occurred to the writer to try it as a kite and he thus +missed the distinction which attaches to Hargrave's name. + +Sir Hiram Maxim also introduced fore and aft superposed surfaces in his +wondrous flying machine of 1893, but he relied chiefly for the lift upon +his main large surface and this necessitated so many guys, to prevent +distortion, as greatly to increase the head resistance and this, +together with the unstable equilibrium, made it evident that the design +of the machine would have to be changed. + +How Lilienthal Was Killed. + +In 1895, Otto Lilienthal, the father of modern aviation, the man to +whose method of experimenting almost all present successes are due, +after making something like two thousand glides with monoplanes, added +a superposed surface to his apparatus and found the control of it much +improved. The two surfaces were kept apart by two struts or vertical +posts with a few guy wires, but the connecting joints were weak and +there was nothing like trussing. This eventually cost his most useful +life. Two weeks before that distressing loss to science, Herr Wilhelm +Kress, the distinguished and veteran aviator of Vienna, witnessed a +number of glides by Lilienthal with his double-decked apparatus. He +noticed that it was much wracked and wobbly and wrote to me after the +accident: "The connection of the wings and the steering arrangement were +very bad and unreliable. I warned Herr Lilienthal very seriously. He +promised me that he would soon put it in order, but I fear that he did +not attend to it immediately." + +In point of fact, Lilienthal had built a new machine, upon a different +principle, from which he expected great results, and intended to make +but very few more flights with the old apparatus. He unwisely made one +too many and, like Pilcher, was the victim of a distorted apparatus. +Probably one of the joints of the struts gave way, the upper surface +blew back and Lilienthal, who was well forward on the lower surface, was +pitched headlong to destruction. + +Experiments by the Writer. + +In 1896, assisted by Mr. Herring and Mr. Avery, I experimented with +several full sized gliding machines, carrying a man. The first was a +Lilienthal monoplane which was deemed so cranky that it was discarded +after making about one hundred glides, six weeks before Lilienthal's +accident. The second was known as the multiple winged machine and +finally developed into five pairs of pivoted wings, trussed together at +the front and one pair in the rear. It glided at angles of descent of 10 +or 11 degrees or of one in five, and this was deemed too steep. Then +Mr. Herring and myself made computations to analyze the resistances. We +attributed much of them to the five front spars of the wings and on +a sheet of cross-barred paper I at once drew the design for a new +three-decked machine to be built by Mr. Herring. + +Being a builder of bridges, I trussed these surfaces together, in order +to obtain strength and stiffness. When tested in gliding flight the +lower surface was found too near the ground. It was taken off and the +remaining apparatus now consisted of two surfaces connected together +by a girder composed of vertical posts and diagonal ties, specifically +known as a "Pratt truss." Then Mr. Herring and Mr. Avery together +devised and put on an elastic attachment to the tail. This machine +proved a success, it being safe and manageable. Over 700 glides were +made with it at angles of descent of 8 to 10 degrees, or one in six to +one in seven. + +First Proposed by Wenham. + +The elastic tail attachment and the trussing of the connecting frame of +the superposed wings were the only novelties in this machine, for the +superposing of the surfaces had first been proposed by Wenham, but in +accordance with the popular perception, which bestows all the credit +upon the man who adds the last touch making for success to the labors +of his predecessors, the machine has since been known by many persons as +the "Chanute type" of gliders, much to my personal gratification. + +It has since been improved in many ways. Wright Brothers, disregarding +the fashion which prevails among birds, have placed the tail in front +of their apparatus and called it a front rudder, besides placing the +operator in horizontal position instead of upright, as I did; and also +providing a method of warping the wings to preserve equilibrium. Farman +and Delagrange, under the very able guidance and constructive work of +Voisin brothers, then substituted many details, including a box tail for +the dart-like tail which I used. This may have increased the resistance, +but it adds to the steadiness. Now the tendency in France seems to be to +go back to the monoplane. + +Monoplane Idea Wrong. + +The advocates of the single supporting surface are probably mistaken. It +is true that a single surface shows a greater lift per square foot than +superposed surfaces for a given speed, but the increased weight due to +leverage more than counterbalances this advantage by requiring heavy +spars and some guys. I believe that the future aeroplane dynamic flier +will consist of superposed surfaces, and, now that it has been found +that by imbedding suitably shaped spars in the cloth the head resistance +may be much diminished, I see few objections to superposing three, four +or even five surfaces properly trussed, and thus obtaining a compact, +handy, manageable and comparatively light apparatus. [2] + + + +CHAPTER II. THEORY, DEVELOPMENT, AND USE. + + +While every craft that navigates the air is an airship, all airships are +not flying machines. The balloon, for instance, is an airship, but it is +not what is known among aviators as a flying machine. This latter term +is properly used only in referring to heavier-than-air machines which +have no gas-bag lifting devices, and are made to really fly by the +application of engine propulsion. + +Mechanical Birds. + +All successful flying machines--and there are a number of them--are +based on bird action. The various designers have studied bird flight +and soaring, mastered its technique as devised by Nature, and the modern +flying machine is the result. On an exaggerated, enlarged scale the +machines which are now navigating the air are nothing more nor less than +mechanical birds. + +Origin of the Aeroplane. + +Octave Chanute, of Chicago, may well be called "the developer of the +flying machine." Leaving balloons and various forms of gas-bags out +of consideration, other experimenters, notably Langley and Lilienthal, +antedated him in attempting the navigation of the air on aeroplanes, +or flying machines, but none of them were wholly successful, and it +remained for Chanute to demonstrate the practicability of what was then +called the gliding machine. This term was adopted because the apparatus +was, as the name implies, simply a gliding machine, being without motor +propulsion, and intended solely to solve the problem of the best form of +construction. The biplane, used by Chanute in 1896, is still the basis +of most successful flying machines, the only radical difference being +that motors, rudders, etc., have been added. + +Character of Chanute's Experiments. + +It was the privilege of the author of this book to be Mr. Chanute's +guest at Millers, Indiana, in 1896, when, in collaboration with Messrs. +Herring and Avery, he was conducting the series of experiments which +have since made possible the construction of the modern flying machine +which such successful aviators as the Wright brothers and others are +now using. It was a wild country, much frequented by eagles, hawks, and +similar birds. The enthusiastic trio, Chanute, Herring and Avery, would +watch for hours the evolutions of some big bird in the air, agreeing +in the end on the verdict, "When we master the principle of that bird's +soaring without wing action, we will have come close to solving the +problem of the flying machine." + +Aeroplanes of various forms were constructed by Mr. Chanute with the +assistance of Messrs. Herring and Avery until, at the time of the +writer's visit, they had settled upon the biplane, or two-surface +machine. Mr. Herring later equipped this with a rudder, and made other +additions, but the general idea is still the basis of the Wright, +Curtiss, and other machines in which, by the aid of gasolene motors, +long flights have been made. + +Developments by the Wrights. + +In 1900 the Wright brothers, William and Orville, who were then in +the bicycle business in Dayton, Ohio, became interested in Chanute's +experiments and communicated with him. The result was that the Wrights +took up Chanute's ideas and developed them further, making many +additions of their own, one of which was the placing of a rudder in +front, and the location of the operator horizontally on the machine, +thus diminishing by four-fifths the wind resistance of the man's +body. For three years the Wrights experimented with the glider before +venturing to add a motor, which was not done until they had thoroughly +mastered the control of their movements in the air. + +Limits of the Flying Machine. + +In the opinion of competent experts it is idle to look for a commercial +future for the flying machine. There is, and always will be, a limit to +its carrying capacity which will prohibit its employment for passenger +or freight purposes in a wholesale or general way. There are some, of +course, who will argue that because a machine will carry two people +another may be constructed that will carry a dozen, but those who make +this contention do not understand the theory of weight sustentation in +the air; or that the greater the load the greater must be the lifting +power (motors and plane surface), and that there is a limit to these--as +will be explained later on--beyond which the aviator cannot go. + +Some Practical Uses. + +At the same time there are fields in which the flying machine may be +used to great advantage. These are: + +Sports--Flying machine races or flights will always be popular by reason +of the element of danger. It is a strange, but nevertheless a true +proposition, that it is this element which adds zest to all sporting +events. + +Scientific--For exploration of otherwise inaccessible regions such as +deserts, mountain tops, etc. + +Reconnoitering--In time of war flying machines may be used to advantage +to spy out an enemy's encampment, ascertain its defenses, etc. + + + +CHAPTER III. MECHANICAL BIRD ACTION + +In order to understand the theory of the modern flying machine one must +also understand bird action and wind action. In this connection the +following simple experiment will be of interest: + +Take a circular-shaped bit of cardboard, like the lid of a hat box, and +remove the bent-over portion so as to have a perfectly flat surface with +a clean, sharp edge. Holding the cardboard at arm's length, withdraw +your hand, leaving the cardboard without support. What is the result? +The cardboard, being heavier than air, and having nothing to sustain +it, will fall to the ground. Pick it up and throw it, with considerable +force, against the wind edgewise. What happens? Instead of falling to +the ground, the cardboard sails along on the wind, remaining afloat so +long as it is in motion. It seeks the ground, by gravity, only as the +motion ceases, and then by easy stages, instead of dropping abruptly as +in the first instance. + +Here we have a homely, but accurate illustration of the action of the +flying machine. The motor does for the latter what the force of your arm +does for the cardboard--imparts a motion which keeps it afloat. The only +real difference is that the motion given by the motor is continuous and +much more powerful than that given by your arm. The action of the latter +is limited and the end of its propulsive force is reached within a +second or two after it is exerted, while the action of the motor is +prolonged. + +Another Simple Illustration. + +Another simple means of illustrating the principle of flying machine +operation, so far as sustentation and the elevation and depression of +the planes is concerned, is explained in the accompanying diagram. + +A is a piece of cardboard about 2 by 3 inches in size. B is a piece of +paper of the same size pasted to one edge of A. If you bend the paper +to a curve, with convex side up and blow across it as shown in Figure +C, the paper will rise instead of being depressed. The dotted lines show +that the air is passing over the top of the curved paper and yet, no +matter how hard you may blow, the effect will be to elevate the paper, +despite the fact that the air is passing over, instead of under the +curved surface. + +In Figure D we have an opposite effect. Here the paper is in a curve +exactly the reverse of that shown in Figure C, bringing the concave side +up. Now if you will again blow across the surface of the card the action +of the paper will be downward--it will be impossible to make it rise. +The harder you blow the greater will be the downward movement. + +Principle In General Use. + +This principle is taken advantage of in the construction of all +successful flying machines. Makers of monoplanes and biplanes alike +adhere to curved bodies, with the concave surface facing downward. +Straight planes were tried for a time, but found greatly lacking in the +power of sustentation. By curving the planes, and placing the concave +surface downward, a sort of inverted bowl is formed in which the air +gathers and exerts a buoyant effect. Just what the ratio of the curve +should be is a matter of contention. In some instances one inch to the +foot is found to be satisfactory; in others this is doubled, and there +are a few cases in which a curve of as much as 3 inches to the foot has +been used. + +Right here it might be well to explain that the word "plane" applied to +flying machines of modern construction is in reality a misnomer. Plane +indicates a flat, level surface. As most successful flying machines have +curved supporting surfaces it is clearly wrong to speak of "planes," or +"aeroplanes." Usage, however, has made the terms convenient and, as they +are generally accepted and understood by the public, they are used in +like manner in this volume. + +Getting Under Headway. + +A bird, on first rising from the ground, or beginning its flight from +a tree, will flap its wings to get under headway. Here again we have +another illustration of the manner in which a flying machine gets under +headway--the motor imparts the force necessary to put the machine into +the air, but right here the similarity ceases. If the machine is to be +kept afloat the motor must be kept moving. A flying machine will not +sustain itself; it will not remain suspended in the air unless it is +under headway. This is because it is heavier than air, and gravity draws +it to the ground. + +Puzzle in Bird Soaring. + +But a bird, which is also heavier than air, will remain suspended, in a +calm, will even soar and move in a circle, without apparent movement +of its wings. This is explained on the theory that there are generally +vertical columns of air in circulation strong enough to sustain a bird, +but much too weak to exert any lifting power on a flying machine, It is +easy to understand how a bird can remain suspended when the wind is +in action, but its suspension in a seeming dead calm was a puzzle +to scientists until Mr. Chanute advanced the proposition of vertical +columns of air. + +Modeled Closely After Birds. + +So far as possible, builders of flying machines have taken what may +be called "the architecture" of birds as a model. This is readily +noticeable in the form of construction. When a bird is in motion its +wings (except when flapping) are extended in a straight line at right +angles to its body. This brings a sharp, thin edge against the air, +offering the least possible surface for resistance, while at the same +time a broad surface for support is afforded by the flat, under side of +the wings. Identically the same thing is done in the construction of the +flying machine. + +Note, for instance, the marked similarity in form as shown in the +illustration in Chapter II. Here A is the bird, and B the general +outline of the machine. The thin edge of the plane in the latter is +almost a duplicate of that formed by the outstretched wings of the bird, +while the rudder plane in the rear serves the same purpose as the bird's +tail. + + + +CHAPTER IV. VARIOUS FORMS OF FLYING MACHINES. + +There are three distinct and radically different forms of flying +machines. These are: + +Aeroplanes, helicopters and ornithopers. + +Of these the aeroplane takes precedence and is used almost exclusively +by successful aviators, the helicopters and ornithopers having been +tried and found lacking in some vital features, while at the same +time in some respects the helicopter has advantages not found in the +aeroplane. + +What the Helicopter Is. + +The helicopter gets its name from being fitted with vertical propellers +or helices (see illustration) by the action of which the machine is +raised directly from the ground into the air. This does away with the +necessity for getting the machine under a gliding headway before +it floats, as is the case with the aeroplane, and consequently the +helicopter can be handled in a much smaller space than is required for +an aeroplane. This, in many instances, is an important advantage, but it +is the only one the helicopter possesses, and is more than overcome +by its drawbacks. The most serious of these is that the helicopter is +deficient in sustaining capacity, and requires too much motive power. + +Form of the Ornithopter. + +The ornithopter has hinged planes which work like the wings of a bird. +At first thought this would seem to be the correct principle, and most +of the early experimenters conducted their operations on this line. It +is now generally understood, however, that the bird in soaring is in +reality an aeroplane, its extended wings serving to sustain, as well as +propel, the body. At any rate the ornithoper has not been successful in +aviation, and has been interesting mainly as an ingenious toy. Attempts +to construct it on a scale that would permit of its use by man in actual +aerial flights have been far from encouraging. + +Three Kinds of Aeroplanes. + +There are three forms of aeroplanes, with all of which more or less +success has been attained. These are: + +The monoplane, a one-surfaced plane, like that used by Bleriot. + +The biplane, a two-surfaced plane, now used by the Wrights, Curtiss, +Farman, and others. + +The triplane, a three-surfaced plane This form is but little used, +its only prominent advocate at present being Elle Lavimer, a Danish +experimenter, who has not thus far accomplished much. + +Whatever of real success has been accomplished in aviation may be +credited to the monoplane and biplane, with the balance in favor of +the latter. The monoplane is the more simple in construction and, where +weight-sustaining capacity is not a prime requisite, may probably be +found the most convenient. This opinion is based on the fact that the +smaller the surface of the plane the less will be the resistance offered +to the air, and the greater will be the speed at which the machine +may be moved. On the other hand, the biplane has a much greater plane +surface (double that of a monoplane of the same size) and consequently +much greater weight-carrying capacity. + +Differences in Biplanes. + +While all biplanes are of the same general construction so far as the +main planes are concerned, each aviator has his own ideas as to the +"rigging." + +Wright, for instance, places a double horizontal rudder in front, with +a vertical rudder in the rear. There are no partitions between the +main planes, and the bicycle wheels used on other forms are replaced by +skids. + +Voisin, on the contrary, divides the main planes with vertical +partitions to increase stability in turning; uses a single-plane +horizontal rudder in front, and a big box-tail with vertical rudder at +the rear; also the bicycle wheels. + +Curtiss attaches horizontal stabilizing surfaces to the upper plane; +has a double horizontal rudder in front, with a vertical rudder +and horizontal stabilizing surfaces in rear. Also the bicycle wheel +alighting gear. + + + +CHAPTER V. CONSTRUCTING A GLIDING MACHINE. + +First decide upon the kind of a machine you want--monoplane, biplane, +or triplane. For a novice the biplane will, as a rule, be found the +most satisfactory as it is more compact and therefore the more easily +handled. This will be easily understood when we realize that the surface +of a flying machine should be laid out in proportion to the amount of +weight it will have to sustain. The generally accepted rule is that 152 +square feet of surface will sustain the weight of an average-sized man, +say 170 pounds. Now it follows that if these 152 square feet of surface +are used in one plane, as in the monoplane, the length and width of this +plane must be greater than if the same amount of surface is secured by +using two planes--the biplane. This results in the biplane being more +compact and therefore more readily manipulated than the monoplane, which +is an important item for a novice. + +Glider the Basis of Success. + +Flying machines without motors are called gliders. In making a flying +machine you first construct the glider. If you use it in this form it +remains a glider. If you install a motor it becomes a flying machine. +You must have a good glider as the basis of a successful flying machine. + +It will be well for the novice, the man who has never had any experience +as an aviator, to begin with a glider and master its construction and +operation before he essays the more pretentious task of handling a +fully-equipped flying machine. In fact, it is essential that he should +do so. + +Plans for Handy Glider. + +A glider with a spread (advancing edge) of 20 feet, and a breadth or +depth of 4 feet, will be about right to begin with. Two planes of this +size will give the 152 square yards of surface necessary to sustain a +man's weight. Remember that in referring to flying machine measurements +"spread" takes the place of what would ordinarily be called "length," +and invariably applies to the long or advancing edge of the machine +which cuts into the air. Thus, a glider is spoken of as being 20 feet +spread, and 4 feet in depth. So far as mastering the control of the +machine is concerned, learning to balance one's self in the air, guiding +the machine in any desired direction by changing the position of the +body, etc., all this may be learned just as readily, and perhaps more +so, with a 20-foot glider than with a larger apparatus. + +Kind of Material Required. + +There are three all-important features in flying machine construction, +viz.: lightness, strength and extreme rigidity. Spruce is the wood +generally used for glider frames. Oak, ash and hickory are all stronger, +but they are also considerably heavier, and where the saving of weight +is essential, the difference is largely in favor of spruce. This will be +seen in the following table: + + Weight Tensile Compressive + per cubic ft. Strength Strength + Wood in lbs. lbs. per sq. in. lbs. per sq in. + Hickory 53 12,000 8,500 + Oak 50 12,000 9,000 + Ash 38 12,000 6,000 + Walnut 38 8,000 6,000 + Spruce 25 8,000 5,000 + Pine 25 5,000 4,500 + + +Considering the marked saving in weight spruce has a greater percentage +of tensile strength than any of the other woods. It is also easier to +find in long, straight-grained pieces free from knots, and it is this +kind only that should be used in flying machine construction. + +You will next need some spools or hanks of No. 6 linen shoe +thread, metal sockets, a supply of strong piano wire, a quantity of +closely-woven silk or cotton cloth, glue, turnbuckles, varnish, etc. + +Names of the Various Parts. + +The long strips, four in number, which form the front and rear edges of +the upper and lower frames, are called the horizontal beams. These are +each 20 feet in length. These horizontal beams are connected by upright +strips, 4 feet long, called stanchions. There are usually 12 of these, +six on the front edge, and six on the rear. They serve to hold the upper +plane away from the lower one. Next comes the ribs. These are 4 feet in +length (projecting for a foot over the rear beam), and while intended +principally as a support to the cloth covering of the planes, also +tend to hold the frame together in a horizontal position just as the +stanchions do in the vertical. There are forty-one of these ribs, +twenty-one on the upper and twenty on the lower plane. Then come the +struts, the main pieces which join the horizontal beams. All of these +parts are shown in the illustrations, reference to which will make the +meaning of the various names clear. + +Quantity and Cost of Material. + +For the horizontal beams four pieces of spruce, 20 feet long, 1 1/2 +inches wide and 3/4 inch thick are necessary. These pieces must be +straight-grain, and absolutely free from knots. If it is impossible to +obtain clear pieces of this length, shorter ones may be spliced, but +this is not advised as it adds materially to the weight. The twelve +stanchions should be 4 feet long and 7/8 inch in diameter and rounded +in form so as to offer as little resistance as possible to the wind. The +struts, there are twelve of them, are 3 feet long by 11/4 x 1/2 inch. +For a 20-foot biplane about 20 yards of stout silk or unbleached muslin, +of standard one yard width, will be needed. The forty-one ribs are +each 4 feet long, and 1/2 inch square. A roll of No. 12 piano wire, +twenty-four sockets, a package of small copper tacks, a pot of glue, and +similar accessories will be required. The entire cost of this material +should not exceed $20. The wood and cloth will be the two largest +items, and these should not cost more than $10. This leaves $10 for the +varnish, wire, tacks, glue, and other incidentals. This estimate is +made for cost of materials only, it being taken for granted that the +experimenter will construct his own glider. Should the services of a +carpenter be required the total cost will probably approximate $60 or +$70. + +Application of the Rudders. + +The figures given also include the expense of rudders, but the details +of these have not been included as the glider is really complete without +them. Some of the best flights the writer ever saw were made by Mr. A. +M. Herring in a glider without a rudder, and yet there can be no doubt +that a rudder, properly proportioned and placed, especially a rear +rudder, is of great value to the aviator as it keeps the machine with +its head to the wind, which is the only safe position for a novice. For +initial educational purposes, however, a rudder is not essential as the +glides will, or should, be made on level ground, in moderate, steady +wind currents, and at a modest elevation. The addition of a rudder, +therefore, may well be left until the aviator has become reasonably +expert in the management of his machine. + +Putting the Machine Together. + +Having obtained the necessary material, the first move is to have the +rib pieces steamed and curved. This curve may be slight, about 2 inches +for the 4 feet. While this is being done the other parts should be +carefully rounded so the square edges will be taken off. This may be +done with sand paper. Next apply a coat of shellac, and when dry rub +it down thoroughly with fine sand paper. When the ribs are curved treat +them in the same way. + +Lay two of the long horizontal frame pieces on the floor 3 feet apart. +Between these place six of the strut pieces. Put one at each end, and +each 4 1/2 feet put another, leaving a 2-foot space in the center. This +will give you four struts 4 1/2 feet apart, and two in the center 2 feet +apart, as shown in the illustration. This makes five rectangles. Be sure +that the points of contact are perfect, and that the struts are exactly +at right angles with the horizontal frames. This is a most important +feature because if your frame "skews" or twists you cannot keep it +straight in the air. Now glue the ends of the struts to the frame +pieces, using plenty of glue, and nail on strips that will hold the +frame in place while the glue is drying. The next day lash the joints +together firmly with the shoe thread, winding it as you would to mend a +broken gun stock, and over each layer put a coating of glue. This done, +the other frame pieces and struts may be treated in the same way, and +you will thus get the foundations for the two planes. + +Another Way of Placing Struts. + +In the machines built for professional use a stronger and more certain +form of construction is desired. This is secured by the placing the +struts for the lower plane under the frame piece, and those for the +upper plane over it, allowing them in each instance to come out flush +with the outer edges of the frame pieces. They are then securely +fastened with a tie plate or clamp which passes over the end of the +strut and is bound firmly against the surface of the frame piece by the +eye bolts of the stanchion sockets. + +Placing the Rib Pieces. + +Take one of the frames and place on it the ribs, with the arched side +up, letting one end of the ribs come flush with the front edge of the +forward frame, and the other end projecting about a foot beyond the rear +frame. The manner of fastening the ribs to the frame pieces is optional. +In some cases they are lashed with shoe thread, and in others clamped +with a metal clamp fastened with 1/2-inch wood screws. Where clamps and +screws are used care should be taken to make slight holes in the wood +with an awl before starting the screws so as to lessen any tendency to +split the wood. On the top frame, twenty-one ribs placed one foot apart +will be required. On the lower frame, because of the opening left for +the operator's body, you will need only twenty. + +Joining the Two Frames. + +The two frames must now be joined together. For this you will need +twenty-four aluminum or iron sockets which may be purchased at a +foundry or hardware shop. These sockets, as the name implies, provide +a receptacle in which the end of a stanchion is firmly held, and have +flanges with holes for eye-bolts which hold them firmly to the frame +pieces, and also serve to hold the guy wires. In addition to these +eye-bolt holes there are two others through which screws are fastened +into the frame pieces. On the front frame piece of the bottom plane +place six sockets, beginning at the end of the frame, and locating them +exactly opposite the struts. Screw the sockets into position with wood +screws, and then put the eye-bolts in place. Repeat the operation on the +rear frame. Next put the sockets for the upper plane frame in place. + +You are now ready to bring the two planes together. Begin by inserting +the stanchions in the sockets in the lower plane. The ends may need a +little rubbing with sandpaper to get them into the sockets, but care +must be taken to have them fit snugly. When all the stanchions are in +place on the lower plane, lift the upper plane into position, and fit +the sockets over the upper ends of the stanchions. + +Trussing with Guy Wires. + +The next move is to "tie" the frame together rigidly by the aid of guy +wires. This is where the No. 12 piano wire comes in. Each rectangle +formed by the struts and stanchions with the exception of the small +center one, is to be wired separately as shown in the illustration. At +each of the eight corners forming the rectangle the ring of one of the +eye-bolts will be found. There are two ways of doing this "tieing," or +trussing. One is to run the wires diagonally from eye-bolt to eye-bolt, +depending upon main strength to pull them taut enough, and then twist +the ends so as to hold. The other is to first make a loop of wire +at each eye-bolt, and connect these loops to the main wires with +turn-buckles. This latter method is the best, as it admits of the +tension being regulated by simply turning the buckle so as to draw the +ends of the wire closer together. A glance at the illustration will make +this plain, and also show how the wires are to be placed. The proper +degree of tension may be determined in the following manner: + +After the frame is wired place each end on a saw-horse so as to lift the +entire frame clear of the work-shop floor. Get under it, in the center +rectangle and, grasping the center struts, one in each hand, put your +entire weight on the structure. If it is properly put together it will +remain rigid and unyielding. Should it sag ever so slightly the tension +of the wires must be increased until any tendency to sag, no matter how +slight it may be, is overcome. + +Putting on the Cloth. + +We are now ready to put on the cloth covering which holds the air and +makes the machine buoyant. The kind of material employed is of small +account so long as it is light, strong, and wind-proof, or nearly so. +Some aviators use what is called rubberized silk, others prefer balloon +cloth. Ordinary muslin of good quality, treated with a coat of light +varnish after it is in place, will answer all the purposes of the +amateur. + +Cut the cloth into strips a little over 4 feet in length. As you have +20 feet in width to cover, and the cloth is one yard wide, you will need +seven strips for each plane, so as to allow for laps, etc. This will +give you fourteen strips. Glue the end of each strip around the front +horizontal beams of the planes, and draw each strip back, over the ribs, +tacking the edges to the ribs as you go along, with small copper or +brass tacks. In doing this keep the cloth smooth and stretched tight. +Tacks should also be used in addition to the glue, to hold the cloth to +the horizontal beams. + +Next, give the cloth a coat of varnish on the clear, or upper side, and +when this is dry your glider will be ready for use. + +Reinforcing the Cloth. + +While not absolutely necessary for amateur purposes, reinforcement +of the cloth, so as to avoid any tendency to split or tear out from +wind-pressure, is desirable. One way of doing this is to tack narrow +strips of some heavier material, like felt, over the cloth where it laps +on the ribs. Another is to sew slips or pockets in the cloth itself and +let the ribs run through them. Still another method is to sew 2-inch +strips (of the same material as the cover) on the cloth, placing them +about one yard apart, but having them come in the center of each piece +of covering, and not on the laps where the various pieces are joined. + +Use of Armpieces. + +Should armpieces be desired, aside from those afforded by the center +struts, take two pieces of spruce, 3 feet long, by 1 x 1 3/4 inches, and +bolt them to the front and rear beams of the lower plane about 14 inches +apart. These will be more comfortable than using the struts, as the +operator will not have to spread his arms so much. In using the struts +the operator, as a rule, takes hold of them with his hands, while with +the armpieces, as the name implies, he places his arms over them, one of +the strips coming under each armpit. + +Frequently somebody asks why the ribs should be curved. The answer is +easy. The curvature tends to direct the air downward toward the rear +and, as the air is thus forced downward, there is more or less of an +impact which assists in propelling the aeroplane upwards. + + + +CHAPTER VI. LEARNING TO FLY. + +Don't be too ambitious at the start. Go slow, and avoid unnecessary +risks. At its best there is an element of danger in aviation which +cannot be entirely eliminated, but it may be greatly reduced and +minimized by the use of common sense. + +Theoretically, the proper way to begin a glide is from the top of an +incline, facing against the wind, so that the machine will soar until +the attraction of gravitation draws it gradually to the ground. This is +the manner in which experienced aviators operate, but it must be kept in +mind that these men are experts. They understand air currents, know how +to control the action and direction of their machines by shifting the +position of their bodies, and by so doing avoid accidents which would be +unavoidable by a novice. + +Begin on Level Ground. + +Make your first flights on level ground, having a couple of men to +assist you in getting the apparatus under headway. Take your position in +the center rectangle, back far enough to give the forward edges of the +glider an inclination to tilt upward very slightly. Now start and run +forward at a moderately rapid gait, one man at each end of the glider +assisting you. As the glider cuts into the air the wind will catch under +the uplifted edges of the curved planes, and buoy it up so that it will +rise in the air and take you with it. This rise will not be great, just +enough to keep you well clear of the ground. Now project your legs a +little to the front so as to shift the center of gravity a trifle and +bring the edges of the glider on an exact level with the atmosphere. +This, with the momentum acquired in the start, will keep the machine +moving forward for some distance. + +Effect of Body Movements. + +When the weight of the body is slightly back of the center of gravity +the edges of the advancing planes are tilted slightly upward. The glider +in this position acts as a scoop, taking in the air which, in turn, +lifts it off the ground. When a certain altitude is reached--this varies +with the force of the wind--the tendency to a forward movement is +lost and the glider comes to the ground. It is to prolong the forward +movement as much as possible that the operator shifts the center of +gravity slightly, bringing the apparatus on an even keel as it were by +lowering the advancing edges. This done, so long as there is momentum +enough to keep the glider moving, it will remain afloat. + +If you shift your body well forward it will bring the front edges of +the glider down, and elevate the rear ones. In this way the air will be +"spilled" out at the rear, and, having lost the air support or buoyancy, +the glider comes down to the ground. A few flights will make any +ordinary man proficient in the control of his apparatus by his body +movements, not only as concerns the elevating and depressing of the +advancing edges, but also actual steering. You will quickly learn, +for instance, that, as the shifting of the bodily weight backwards +and forwards affects the upward and downward trend of the planes, so a +movement sideways--to the left or the right--affects the direction in +which the glider travels. + +Ascends at an Angle. + +In ascending, the glider and flying machine, like the bird, makes an +angular, not a vertical flight. Just what this angle of ascension may be +is difficult to determine. It is probable and in fact altogether likely, +that it varies with the force of the wind, weight of the rising body, +power of propulsion, etc. This, in the language of physicists, is the +angle of inclination, and, as a general thing, under normal conditions +(still air) should be put down as about one in ten, or 5 3/4 degrees. +This would be an ideal condition, but it has not, as vet been reached. +The force of the wind affects the angle considerably, as does also the +weight and velocity of the apparatus. In general practice the angle +varies from 23 to 45 degrees. At more than 45 degrees the supporting +effort is overcome by the resistance to forward motion. + +Increasing the speed or propulsive force, tends to lessen the angle at +which the machine may be successfully operated because it reduces the +wind pressure. Most of the modern flying machines are operated at an +angle of 23 degrees, or less. + +Maintaining an Equilibrium. + +Stable equilibrium is one of the main essentials to successful flight, +and this cannot be preserved in an uncertain, gusty wind, especially by +an amateur. The novice should not attempt a glide unless the conditions +are just right. These conditions are: A clear, level space, without +obstructions, such as trees, etc., and a steady wind of not exceeding +twelve miles an hour. Always fly against the wind. + +When a reasonable amount of proficiency in the handling of the machine +on level ground has been acquired the field of practice may be changed +to some gentle slope. In starting from a slope it will be found easier +to keep the machine afloat, but the experience at first is likely to be +very disconcerting to a man of less than iron nerve. As the glider sails +away from the top of the slope the distance between him and the ground +increases rapidly until the aviator thinks he is up a hundred miles +in the air. If he will keep cool, manipulate his apparatus so as to +preserve its equilibrium, and "let nature take its course," he will come +down gradually and safely to the ground at a considerable distance +from the starting place. This is one advantage of starting from an +elevation--your machine will go further. + +But, if the aviator becomes "rattled"; if he loses control of his +machine, serious results, including a bad fall with risk of death, +are almost certain. And yet this practice is just as necessary as the +initial lessons on level ground. When judgment is used, and "haste made +slowly," there is very little real danger. While experimenting with +gliders the Wrights made flights innumerable under all sorts of +conditions and never had an accident of any kind. + +Effects of Wind Currents. + +The larger the machine the more difficult it will be to control its +movements in the air, and yet enlargement is absolutely necessary as +weight, in the form of motor, rudder, etc., is added. + +Air currents near the surface of the ground are diverted by every +obstruction unless the wind is blowing hard enough to remove the +obstruction entirely. Take, for instance, the case of a tree or shrub, +in a moderate wind of from ten to twelve miles an hour. As the wind +strikes the tree it divides, part going to one side and part going to +the other, while still another part is directed upward and goes over +the top of the obstruction. This makes the handling of a glider on +an obstructed field difficult and uncertain. To handle a glider +successfully the place of operation should be clear and the wind +moderate and steady. If it is gusty postpone your flight. In this +connection it will be well to understand the velocity of the wind, and +what it means as shown in the following table: + + Miles per hour Feet per second Pressure per sq. foot + 10 14.7 .492 + 25 36.7 3.075 + 50 73.3 12.300 + 100 146.6 49.200 + +Pressure of wind increases in proportion to the square of the velocity. +Thus wind at 10 miles an hour has four times the pressure of wind at +5 miles an hour. The greater this pressure the large and heavier the +object which can be raised. Any boy who has had experience in flying +kites can testify to this, High winds, however, are almost invariably +gusty and uncertain as to direction, and this makes them dangerous for +aviators. It is also a self-evident fact that, beyond a certain stage, +the harder the wind blows the more difficult it is to make headway +against it. + +Launching Device for Gliders. + +On page 195 will be found a diagram of the various parts of a launcher +for gliders, designed and patented by Mr. Octave Chanute. In describing +this invention in Aeronautics, Mr. Chanute says: + +"In practicing, the track, preferably portable, is generally laid in +the direction of the existing wind and the car, preferably a +light platform-car, is placed on the track. The truck carrying +the winding-drum and its motor is placed to windward a suitable +distance--say from two hundred to one thousand feet--and is firmly +blocked or anchored in line with the portable track, which is preferably +80 or 100 feet in length. The flying or gliding machine to be launched +with its operator is placed on the platform-car at the leeward end of +the portable track. The line, which is preferably a flexible combination +wire-and-cord cable, is stretched between the winding-drum on the track +and detachably secured to the flying or gliding machine, preferably by +means of a trip-hoop, or else held in the hand of the operator, so that +the operator may readily detach the same from the flying-machine when +the desired height is attained." + +How Glider Is Started. + +"Then upon a signal given by the operator the engineer at the motor +puts it into operation, gradually increasing the speed until the line +is wound upon the drum at a maximum speed of, say, thirty miles an +hour. The operator of the flying-machine, whether he stands upright and +carries it on his shoulders, or whether he sits or lies down prone upon +it, adjusts the aeroplane or carrying surfaces so that the wind shall +strike them on the top and press downward instead of upward until the +platform-car under action of the winding-drum and line attains the +required speed. + +"When the operator judges that his speed is sufficient, and this depends +upon the velocity of the wind as well as that of the car moving against +the wind, he quickly causes the front of the flying-machine to tip +upward, so that the relative wind striking on the under side of the +planes or carrying surfaces shall lift the flying machine into the air. +It then ascends like a kite to such height as may be desired by the +operator, who then trips the hook and releases the line from the +machine." + +What the Operator Does. + +"The operator being now free in the air has a certain initial velocity +imparted by the winding-drum and line and also a potential energy +corresponding to his height above the ground. If the flying or gliding +machine is provided with a motor, he can utilize that in his further +flight, and if it is a simple gliding machine without motor he can make +a descending flight through the air to such distance as corresponds to +the velocity acquired and the height gained, steering meanwhile by the +devices provided for that purpose. + +"The simplest operation or maneuver is to continue the flight straight +ahead against the wind; but it is possible to vary this course to the +right or left, or even to return in downward flight with the wind to +the vicinity of the starting-point. Upon nearing the ground the operator +tips upward his carrying-surfaces and stops his headway upon the +cushion of increased air resistance so caused. The operator is in no way +permanently fastened to his machine, and the machine and the operator +simply rest upon the light platform-car, so that the operator is free +to rise with the machine from the car whenever the required initial +velocity is attained. + +Motor For the Launcher. + +"The motor may be of any suitable kind or construction, but is +preferably an electric or gasolene motor. The winding-drum is furnished +with any suitable or customary reversing-guide to cause the line to +wind smoothly and evenly upon the drum. The line is preferably a cable +composed of flexible wire and having a cotton or other cord core to +increase its flexibility. The line extends from the drum to the flying +or gliding machine. Its free end may, if desired, be grasped and held +by the operator until the flying-machine ascends to the desired height, +when by simply letting go of the line the operator may continue his +flight free. The line, however, is preferably connected to the flying +or gliding machine directly by a trip-hook having a handle or trip lever +within reach of the operator, so that when he ascends to the required +height he may readily detach the line from the flying or gliding +machine." + + + +CHAPTER VII. PUTTING ON THE RUDDER. + +Gliders as a rule have only one rudder, and this is in the rear. It +tends to keep the apparatus with its head to the wind. Unlike the rudder +on a boat it is fixed and immovable. The real motor-propelled flying +machine, generally has both front and rear rudders manipulated by wire +cables at the will of the operator. + +Allowing that the amateur has become reasonably expert in the +manipulation of the glider he should, before constructing an actual +flying machine, equip his glider with a rudder. + +Cross Pieces for Rudder Beam. + +To do this he should begin by putting in a cross piece, 2 feet long by +1/4 x 3/4 inches between the center struts, in the lower plane. This may +be fastened to the struts with bolts or braces. The former method is +preferable. On this cross piece, and on the rear frame of the plane +itself, the rudder beam is clamped and bolted. This rudder beam is 8 +feet 11 inches long. Having put these in place duplicate them in exactly +the same manner and dimensions from the upper frame The cross pieces on +which the ends of the rudder beams are clamped should be placed about +one foot in advance of the rear frame beam. + +The Rudder Itself. + +The next step is to construct the rudder itself. This consists of two +sections, one horizontal, the other vertical. The latter keeps +the aeroplane headed into the wind, while the former keeps it +steady--preserves the equilibrium. + +The rudder beams form the top and bottom frames of the vertical rudder. +To these are bolted and clamped two upright pieces, 3 feet, 10 inches +in length, and 3/4 inch in cross section. These latter pieces are placed +about two feet apart. This completes the framework of the vertical +rudder. See next page (59). + +For the horizontal rudder you will require two strips 6 feet long, and +four 2 feet long. Find the exact center of the upright pieces on the +vertical rudder, and at this spot fasten with bolts the long pieces of +the horizontal, placing them on the outside of the vertical strips. Next +join the ends of the horizontal strips with the 2-foot pieces, using +small screws and corner braces. This done you will have two of the +2-foot pieces left. These go in the center of the horizontal frame, +"straddling" the vertical strips, as shown in the illustration. + +The framework is to be covered with cloth in the same manner as the +planes. For this about ten yards will be needed. + +Strengthening the Rudder. + +To ensure rigidity the rudder must be stayed with guy wires. For this +purpose the No. 12 piano wire is the best. Begin by running two of these +wires from the top eye-bolts of stanchions 3 and 4, page 37, to rudder +beam where it joins the rudder planes, fastening them at the bottom. +Then run two wires from the top of the rudder beam at the same point, +to the bottom eye-bolts of the same stanchions. This will give you +four diagonal wires reaching from the rudder beam to the top and bottom +planes of the glider. Now, from the outer ends of the rudder frame run +four similar diagonal wires to the end of the rudder beam where it rests +on the cross piece. You will then have eight truss wires strengthening +the connection of the rudder to the main body of the glider. + +The framework of the rudder planes is then to be braced in the same way, +which will take eight more wires, four for each rudder plane. All the +wires are to be connected at one end with turn-buckles so the tension +may be regulated as desired. + +In forming the rudder frame it will be well to mortise the corners, tack +them together with small nails, and then put in a corner brace in the +inside of each joint. In doing this bear in mind that the material to be +thus fastened is light, and consequently the lightest of nails, screws, +bolts and corner pieces, etc., is necessary. + + + +CHAPTER VIII. THE REAL FLYING MACHINE. + +We will now assume that you have become proficient enough to warrant an +attempt at the construction of a real flying machine--one that will not +only remain suspended in the air at the will of the operator, but make +respectable progress in whatever direction he may desire to go. The +glider, it must be remembered, is not steerable, except to a limited +extent, and moves only in one direction--against the wind. Besides this +its power of flotation--suspension in the air--is circumscribed. + +Larger Surface Area Required. + +The real flying machine is the glider enlarged, and equipped with +motor and propeller. The first thing to do is to decide upon the size +required. While a glider of 20 foot spread is large enough to sustain a +man it could not under any possible conditions, be made to rise with the +weight of the motor, propeller and similar equipment added. As the load +is increased so must the surface area of the planes be increased. +Just what this increase in surface area should be is problematical as +experienced aviators disagree, but as a general proposition it may be +placed at from three to four times the area of a 20-foot glider. [3] + +Some Practical Examples. + +The Wrights used a biplane 41 feet in spread, and 6 1/2 ft. deep. This, +for the two planes, gives a total surface area of 538 square feet, +inclusive of auxiliary planes. This sustains the engine equipment, +operator, etc., a total weight officially announced at 1,070 pounds. It +shows a lifting capacity of about two pounds to the square foot of plane +surface, as against a lifting capacity of about 1/2 pound per square +foot of plane surface for the 20-foot glider. This same Wright machine +is also reported to have made a successful flight, carrying a total load +of 1,100 pounds, which would be over two pounds for each square foot of +surface area, which, with auxiliary planes, is 538 square feet. + +To attain the same results in a monoplane, the single surface would +have to be 60 feet in spread and 9 feet deep. But, while this is the +mathematical rule, Bleriot has demonstrated that it does not always hold +good. On his record-breaking trip across the English channel, July 25th, +1909, the Frenchman was carried in a monoplane 24 1/2 feet in spread, +and with a total sustaining surface of 150 1/2 square feet. The total +weight of the outfit, including machine, operator and fuel sufficient +for a three-hour run, was only 660 pounds. With an engine of (nominally) +25 horsepower the distance of 21 miles was covered in 37 minutes. + +Which is the Best? + +Right here an established mathematical quantity is involved. A small +plane surface offers less resistance to the air than a large one and +consequently can attain a higher rate of speed. As explained further +on in this chapter speed is an important factor in the matter of +weight-sustaining capacity. A machine that travels one-third faster +than another can get along with one-half the surface area of the latter +without affecting the load. See the closing paragraph of this chapter on +this point. In theory the construction is also the simplest, but this is +not always found to be so in practice. The designing and carrying +into execution of plans for an extensive area like that of a monoplane +involves great skill and cleverness in getting a framework that will be +strong enough to furnish the requisite support without an undue excess +of weight. This proposition is greatly simplified in the biplane and, +while the speed attained by the latter may not be quite so great as that +of the monoplane, it has much larger weight-carrying capacity. + +Proper Sizes For Frame. + +Allowing that the biplane form is selected the construction may be +practically identical with that of the 20-foot glider described in +Chapter V., except as to size and elimination of the armpieces. In +size the surface planes should be about twice as large as those of +the 20-foot glider, viz: 40 feet spread instead of 20, and 6 feet deep +instead of 3. The horizontal beams, struts, stanchions, ribs, etc., +should also be increased in size proportionately. + +While care in the selection of clear, straight-grained timber is +important in the glider, it is still more important in the construction +of a motor-equipped flying machine as the strain on the various parts +will be much greater. + +How to Splice Timbers. + +It is practically certain that you will have to resort to splicing the +horizontal beams as it will be difficult, if not impossible, to find +40-foot pieces of timber totally free from knots and worm holes, and of +straight grain. + +If splicing is necessary select two good 20-foot pieces, 3 inches wide +and 1 1/2 inches thick, and one 10-foot long, of the same thickness and +width. Plane off the bottom sides of the 10-foot strip, beginning about +two feet back from each end, and taper them so the strip will be about +3/4 inch thick at the extreme ends. Lay the two 20-foot beams end to +end, and under the joint thus made place the 10-foot strip, with the +planed-off ends downward. The joint of the 20-foot pieces should be +directly in the center of the 10-foot piece. Bore ten holes (with a +1/4-inch augur) equi-distant apart through the 20-foot strips and the +10-foot strip under them. Through these holes run 1/4-inch stove bolts +with round, beveled heads. In placing these bolts use washers top and +bottom, one between the head and the top beam, and the other between the +bottom beam and the screw nut which holds the bolt. Screw the nuts down +hard so as to bring the two beams tightly together, and you will have a +rigid 40-foot beam. + +Splicing with Metal Sleeves. + +An even better way of making a splice is by tonguing and grooving the +ends of the frame pieces and enclosing them in a metal sleeve, but +it requires more mechanical skill than the method first named. The +operation of tonguing and grooving is especially delicate and calls for +extreme nicety of touch in the handling of tools, but if this dexterity +is possessed the job will be much more satisfactory than one done with a +third timber. + +As the frame pieces are generally about 1 1/2 inch in diameter, the +tongue and the groove into which the tongue fits must be correspondingly +small. Begin by sawing into one side of one of the frame pieces about +4 inches back from the end. Make the cut about 1/2 inch deep. Then turn +the piece over and duplicate the cut. Next saw down from the end +to these cuts. When the sawed-out parts are removed you will have a +"tongue" in the end of the frame timber 4 inches long and 1/2 inch +thick. The next move is to saw out a 5/8-inch groove in the end of the +frame piece which is to be joined. You will have to use a small chisel +to remove the 5/8-inch bit. This will leave a groove into which the +tongue will fit easily. + +Joining the Two Pieces. + +Take a thin metal sleeve--this is merely a hollow tube of aluminum +or brass open at each end--8 inches long, and slip it over either the +tongued or grooved end of one of the frame timbers. It is well to have +the sleeve fit snugly, and this may necessitate a sand-papering of the +frame pieces so the sleeve will slip on. + +Push the sleeve well back out of the way. Cover the tongue thoroughly +with glue, and also put some on the inside of the groove. Use plenty +of glue. Now press the tongue into the groove, and keep the ends firmly +together until the glue is thoroughly dried. Rub off the joint lightly +with sand-paper to remove any of the glue which may have oozed out, and +slip the sleeve into place over the joint. Tack the sleeve in position +with small copper tacks, and you will have an ideal splice. + +The same operation is to be repeated on each of the four frame pieces. +Two 20-foot pieces joined in this way will give a substantial frame, but +when suitable timber of this kind can not be had, three pieces, each 6 +feet 11 inches long, may be used. This would give 20 feet 9 inches, of +which 8 inches will be taken up in the two joints, leaving the frame 20 +feet 1 inch long. + +Installation of Motor. + +Next comes the installation of the motor. The kinds and efficiency of +the various types are described in the following chapter (IX). All we +are interested in at this point is the manner of installation. This +varies according to the personal ideas of the aviator. Thus one man puts +his motor in the front of his machine, another places it in the center, +and still another finds the rear of the frame the best. All get +good results, the comparative advantages of which it is difficult +to estimate. Where one man, as already explained, flies faster than +another, the one beaten from the speed standpoint has an advantage in +the matter of carrying weight, etc. + +The ideas of various well-known aviators as to the correct placing of +motors may be had from the following: + +Wrights--In rear of machine and to one side. + +Curtiss--Well to rear, about midway between upper and lower planes. + +Raich--In rear, above the center. + +Brauner-Smith--In exact center of machine. + +Van Anden--In center. + +Herring-Burgess--Directly behind operator. + +Voisin--In rear, and on lower plane. + +Bleriot--In front. + +R. E. P.--In front. + +The One Chief Object. + +An even distribution of the load so as to assist in maintaining the +equilibrium of the machine, should be the one chief object in deciding +upon the location of the motor. It matters little what particular spot +is selected so long as the weight does not tend to overbalance the +machine, or to "throw it off an even keel." It is just like loading +a vessel, an operation in which the expert seeks to so distribute +the weight of the cargo as to keep the vessel in a perfectly upright +position, and prevent a "list" or leaning to one side. The more evenly +the cargo is distributed the more perfect will be the equilibrium of the +vessel and the better it can be handled. Sometimes, when not properly +stowed, the cargo shifts, and this at once affects the position of the +craft. When a ship "lists" to starboard or port a preponderating weight +of the cargo has shifted sideways; if bow or stern is unduly depressed +it is a sure indication that the cargo has shifted accordingly. In +either event the handling of the craft becomes not only difficult, but +extremely hazardous. Exactly the same conditions prevail in the handling +of a flying machine. + +Shape of Machine a Factor. + +In placing the motor you must be governed largely by the shape and +construction of the flying machine frame. If the bulk of the weight +of the machine and auxiliaries is toward the rear, then the natural +location for the motor will be well to the front so as to counterbalance +the excess in rear weight. In the same way if the preponderance of the +weight is forward, then the motor should be placed back of the center. + +As the propeller blade is really an integral part of the motor, the +latter being useless without it, its placing naturally depends upon the +location selected for the motor. + +Rudders and Auxiliary Planes. + +Here again there is great diversity of opinion among aviators as to +size, location and form. The striking difference of ideas in this +respect is well illustrated in the choice made by prominent makers as +follows: + +Voisin--horizontal rudder, with two wing-like planes, in front; box-like +longitudinal stability plane in rear, inside of which is a vertical +rudder. + +Wright--large biplane horizontal rudder in front at considerable +distance--about 10 feet--from the main planes; vertical biplane rudder +in rear; ends of upper and lower main planes made flexible so they may +be moved. + +Curtiss--horizontal biplane rudder, with vertical damping plane between +the rudder planes about 10 feet in front of main planes; vertical rudder +in rear; stabilizing planes at each end of upper main plane. + +Bleriot--V-shaped stabilizing fin, projecting from rear of plane, with +broad end outward; to the broad end of this fin is hinged a vertical +rudder; horizontal biplane rudder, also in rear, under the fin. + +These instances show forcefully the wide diversity of opinion existing +among experienced aviators as to the best manner of placing the rudders +and stabilizing, or auxiliary planes, and make manifest how hopeless +would be the task of attempting to select any one form and advise its +exclusive use. + +Rudder and Auxiliary Construction. + +The material used in the construction of the rudders and auxiliary +planes is the same as that used in the main planes--spruce for the +framework and some kind of rubberized or varnished cloth for the +covering. The frames are joined and wired in exactly the same manner +as the frames of the main planes, the purpose being to secure the same +strength and rigidity. Dimensions of the various parts depend upon the +plan adopted and the size of the main plane. + +No details as to exact dimensions of these rudders and auxiliary planes +are obtainable. The various builders, while willing enough to supply +data as to the general measurements, weight, power, etc., of their +machines, appear to have overlooked the details of the auxiliary parts, +thinking, perhaps, that these were of no particular import to the +general public. In the Wright machine, the rear horizontal and front +vertical rudders may be set down as being about one-quarter (probably a +little less) the size of the main supporting planes. + +Arrangement of Alighting Gear. + +Most modern machines are equipped with an alighting gear, which not +only serves to protect the machine and aviator from shock or injury in +touching the ground, but also aids in getting under headway. All the +leading makes, with the exception of the Wright, are furnished with a +frame carrying from two to five pneumatic rubber-tired bicycle wheels. +In the Curtiss and Voisin machines one wheel is placed in front and two +in the rear. In the Bleriot and other prominent machines the reverse is +the rule--two wheels in front and one in the rear. Farman makes use of +five wheels, one in the extreme rear, and four, arranged in pairs, a +little to the front of the center of the main lower plane. + +In place of wheels the Wright machine is equipped with a skid-like +device consisting of two long beams attached to the lower plane by +stanchions and curving up far in front, so as to act as supports to the +horizontal rudder. + +Why Wood Is Favored. + +A frequently asked question is: "Why is not aluminum, or some similar +metal, substituted for wood." Wood, particularly spruce, is preferred +because, weight considered, it is much stronger than aluminum, and this +is the lightest of all metals. In this connection the following table +will be of interest: + + Compressive + Weight Tensile Strength Strength + per cubic foot per sq. inch per sq. inch + Material in lbs. in lbs. in lbs. + Spruce.... 25 8,000 5,000 + Aluminum 162 16,000 ...... + Brass (sheet) 510 23,000 12,000 + Steel (tool) 490 100,000 40,000 + Copper (sheet) 548 30,000 40,000 + +As extreme lightness, combined with strength, especially tensile +strength, is the great essential in flying-machine construction, it can +be readily seen that the use of metal, even aluminum, for the framework, +is prohibited by its weight. While aluminum has double the strength +of spruce wood it is vastly heavier, and thus the advantage it has in +strength is overbalanced many times by its weight. The specific gravity +of aluminum is 2.50; that of spruce is only 0.403. + +Things to Be Considered. + +In laying out plans for a flying machine there are five important points +which should be settled upon before the actual work of construction is +started. These are: + +First--Approximate weight of the machine when finished and equipped. + +Second--Area of the supporting surface required. + +Third--Amount of power that will be necessary to secure the desired +speed and lifting capacity. + +Fourth--Exact dimensions of the main framework and of the auxiliary +parts. + +Fifth--Size, speed and character of the propeller. + +In deciding upon these it will be well to take into consideration +the experience of expert aviators regarding these features as given +elsewhere. (See Chapter X.) + +Estimating the Weights Involved. + +In fixing upon the probable approximate weight in advance of +construction much, of course, must be assumed. This means that it will +be a matter of advance estimating. If a two-passenger machine is to be +built we will start by assuming the maximum combined weight of the two +people to be 350 pounds. Most of the professional aviators are lighter +than this. Taking the medium between the weights of the Curtiss and +Wright machines we have a net average of 850 pounds for the framework, +motor, propeller, etc. This, with the two passengers, amounts to 1,190 +pounds. As the machines quoted are in successful operation it will be +reasonable to assume that this will be a safe basis to operate on. + +What the Novice Must Avoid. + +This does not mean, however, that it will be safe to follow these +weights exactly in construction, but that they will serve merely as +a basis to start from. Because an expert can turn out a machine, +thoroughly equipped, of 850 pounds weight, it does not follow that a +novice can do the same thing. The expert's work is the result of years +of experience, and he has learned how to construct frames and motor +plants of the utmost lightness and strength. + +It will be safer for the novice to assume that he can not duplicate the +work of such men as Wright and Curtiss without adding materially to the +gross weight of the framework and equipment minus passengers. + +How to Distribute the Weight. + +Let us take 1,030 pounds as the net weight of the machine as against the +same average in the Wright and Curtiss machines. Now comes the question +of distributing this weight between the framework, motor, and other +equipment. As a general proposition the framework should weigh about +twice as much as the complete power plant (this is for amateur work). + +The word "framework" indicates not only the wooden frames of the main +planes, auxiliary planes, rudders, etc., but the cloth coverings as +well--everything in fact except the engine and propeller. + +On the basis named the framework would weigh 686 pounds, and the power +plant 344. These figures are liberal, and the results desired may be +obtained well within them as the novice will learn as he makes progress +in the work. + +Figuring on Surface Area. + +It was Prof. Langley who first brought into prominence in connection +with flying machine construction the mathematical principle that the +larger the object the smaller may be the relative area of support. As +explained in Chapter XIII, there are mechanical limits as to size which +it is not practical to exceed, but the main principle remains in effect. + +Take two aeroplanes of marked difference in area of surface. The larger +will, as a rule, sustain a greater weight in relative proportion to +its area than the smaller one, and do the work with less relative +horsepower. As a general thing well-constructed machines will average +a supporting capacity of one pound for every one-half square foot of +surface area. Accepting this as a working rule we find that to sustain +a weight of 1,200 pounds--machine and two passengers--we should have 600 +square feet of surface. + +Distributing the Surface Area. + +The largest surfaces now in use are those of the Wright, Voisin and +Antoinette machines--538 square feet in each. The actual sustaining +power of these machines, so far as known, has never been tested to the +limit; it is probable that the maximum is considerably in excess of what +they have been called upon to show. In actual practice the average is a +little over one pound for each one-half square foot of surface area. + +Allowing that 600 square feet of surface will be used, the next question +is how to distribute it to the best advantage. This is another important +matter in which individual preference must rule. We have seen how the +professionals disagree on this point, some using auxiliary planes +of large size, and others depending upon smaller auxiliaries with an +increase in number so as to secure on a different plan virtually the +same amount of surface. + +In deciding upon this feature the best thing to do is to follow the +plans of some successful aviator, increasing the area of the auxiliaries +in proportion to the increase in the area of the main planes. Thus, if +you use 600 square feet of surface where the man whose plans you +are following uses 500, it is simply a matter of making your planes +one-fifth larger all around. + +The Cost of Production. + +Cost of production will be of interest to the amateur who essays to +construct a flying machine. Assuming that the size decided upon is +double that of the glider the material for the framework, timber, cloth, +wire, etc., will cost a little more than double. This is because it must +be heavier in proportion to the increased size of the framework, and +heavy material brings a larger price than the lighter goods. If we allow +$20 as the cost of the glider material it will be safe to put down +the cost of that required for a real flying machine framework at $60, +provided the owner builds it himself. + +As regards the cost of motor and similar equipment it can only be said +that this depends upon the selection made. There are some reliable +aviation motors which may be had as low as $500, and there are others +which cost as much as $2,000. + +Services of Expert Necessary. + +No matter what kind of a motor may be selected the services of an expert +will be necessary in its proper installation unless the amateur has +considerable genius in this line himself. As a general thing $25 should +be a liberal allowance for this work. No matter how carefully the engine +may be placed and connected it will be largely a matter of luck if it is +installed in exactly the proper manner at the first attempt. The chances +are that several alterations, prompted by the results of trials, will +have to be made. If this is the case the expert's bill may readily run +up to $50. If the amateur is competent to do this part of the work the +entire item of $50 may, of course, be cut out. + +As a general proposition a fairly satisfactory flying machine, one that +will actually fly and carry the operator with it, may be constructed for +$750, but it will lack the better qualities which mark the higher priced +machines. This computation is made on the basis of $60 for material, $50 +for services of expert, $600 for motor, etc., and an allowance of $40 +for extras. + +No man who has the flying machine germ in his system will be long +satisfied with his first moderate price machine, no matter how well it +may work. It's the old story of the automobile "bug" over again. The man +who starts in with a modest $1,000 automobile invariably progresses by +easy stages to the $4,000 or $5,000 class. The natural tendency is to +want the biggest and best attainable within the financial reach of the +owner. + +It's exactly the same way with the flying machine convert. The more +proficient he becomes in the manipulation of his car, the stronger +becomes the desire to fly further and stay in the air longer than the +rest of his brethren. This necessitates larger, more powerful, and more +expensive machines as the work of the germ progresses. + +Speed Affects Weight Capacity. + +Don't overlook the fact that the greater speed you can attain the +smaller will be the surface area you can get along with. If a machine +with 500 square feet of sustaining surface, traveling at a speed of +40 miles an hour, will carry a weight of 1,200 pounds, we can cut the +sustaining surface in half and get along with 250 square feet, provided +a speed of 60 miles an hour can be obtained. At 100 miles an hour only +80 square feet of surface area would be required. In both instances the +weight sustaining capacity will remain the same as with the 500 square +feet of surface area--1,200 pounds. + +One of these days some mathematical genius will figure out this problem +with exactitude and we will have a dependable table giving the maximum +carrying capacity of various surface areas at various stated speeds, +based on the dimensions of the advancing edges. At present it is largely +a matter of guesswork so far as making accurate computation goes. +Much depends upon the shape of the machine, and the amount of surface +offering resistance to the wind, etc. + + + +CHAPTER IX. SELECTION OF THE MOTOR. + +Motors for flying machines must be light in weight, of great strength, +productive of extreme speed, and positively dependable in action. +It matters little as to the particular form, or whether air or water +cooled, so long as the four features named are secured. There are at +least a dozen such motors or engines now in use. All are of the gasolene +type, and all possess in greater or lesser degree the desired qualities. +Some of these motors are: + +Renault--8-cylinder, air-cooled; 50 horse power; weight 374 pounds. + +Fiat--8-cylinder, air-cooled; 50 horse power; weight 150 pounds. + +Farcot--8-cylinder, air-cooled; from 30 to 100 horse power, according to +bore of cylinders; weight of smallest, 84 pounds. + +R. E. P.--10-cylinder, air-cooled; 150 horse power; weight 215 pounds. + +Gnome--7 and 14 cylinders, revolving type, air-cooled; 50 and 100 horse +power; weight 150 and 300 pounds. + +Darracq--2 to 14 cylinders, water cooled; 30 to 200 horse power; weight +of smallest 100 pounds. + +Wright--4-cylinder, water-cooled; 25 horse power; weight 200 pounds. + +Antoinette--8 and 16-cylinder, water-cooled; 50 and 100 horse power; +weight 250 and 500 pounds. + +E. N. V.--8-cylinder, water-cooled; from 30 to 80 horse power, according +to bore of cylinder; weight 150 to 400 pounds. + +Curtiss--8-cylinder, water-cooled; 60 horse power; weight 300 pounds. + +Average Weight Per Horse Power. + +It will be noticed that the Gnome motor is unusually light, being about +three pounds to the horse power produced, as opposed to an average of 4 +1/2 pounds per horse power in other makes. This result is secured by +the elimination of the fly-wheel, the engine itself revolving, thus +obtaining the same effect that would be produced by a fly-wheel. The +Farcot is even lighter, being considerably less than three pounds per +horse power, which is the nearest approach to the long-sought engine +equipment that will make possible a complete flying machine the total +weight of which will not exceed one pound per square foot of area. + +How Lightness Is Secured. + +Thus far foreign manufacturers are ahead of Americans in the production +of light-weight aerial motors, as is evidenced by the Gnome and Farcot +engines, both of which are of French make. Extreme lightness is made +possible by the use of fine, specially prepared steel for the cylinders, +thus permitting them to be much thinner than if ordinary forms of steel +were used. Another big saving in weight is made by substituting what are +known as "auto lubricating" alloys for bearings. These alloys are made +of a combination of aluminum and magnesium. + +Still further gains are made in the use of alloy steel tubing instead of +solid rods, and also by the paring away of material wherever it can be +done without sacrificing strength. This plan, with the exclusive use of +the best grades of steel, regardless of cost, makes possible a marked +reduction in weight. + +Multiplicity of Cylinders. + +Strange as it may seem, multiplicity of cylinders does not always add +proportionate weight. Because a 4-cylinder motor weighs say 100 pounds, +it does not necessarily follow that an 8-cylinder equipment will weigh +200 pounds. The reason of this will be plain when it is understood +that many of the parts essential to a 4-cylinder motor will fill the +requirements of an 8-cylinder motor without enlargement or addition. + +Neither does multiplying the cylinders always increase the horsepower +proportionately. If a 4-cylinder motor is rated at 25 horsepower it is +not safe to take it for granted that double the number of cylinders +will give 50 horsepower. Generally speaking, eight cylinders, the bore, +stroke and speed being the same, will give double the power that can be +obtained from four, but this does not always hold good. Just why this +exception should occur is not explainable by any accepted rule. + +Horse Power and Speed. + +Speed is an important requisite in a flying-machine motor, as the +velocity of the aeroplane is a vital factor in flotation. At +first thought, the propeller and similar adjuncts being equal, the +inexperienced mind would naturally argue that a 50-horsepower engine +should produce just double the speed of one of 25-horsepower. That +this is a fallacy is shown by actual performances. The Wrights, using a +25-horsepower motor, have made 44 miles an hour, while Bleriot, with a +50-horsepower motor, has a record of a short-distance flight at the rate +of 52 miles an hour. The fact is that, so far as speed is concerned, +much depends upon the velocity of the wind, the size and shape of the +aeroplane itself, and the size, shape and gearing of the propeller. The +stronger the wind is blowing the easier it will be for the aeroplane +to ascend, but at the same time the more difficult it will be to make +headway against the wind in a horizontal direction. With a strong head +wind, and proper engine force, your machine will progress to a certain +extent, but it will be at an angle. If the aviator desired to keep +on going upward this would be all right, but there is a limit to the +altitude which it is desirable to reach--from 100 to 500 feet for +experts--and after that it becomes a question of going straight ahead. + +Great Waste of Power. + +One thing is certain--even in the most efficient of modern aerial motors +there is a great loss of power between the two points of production and +effect. The Wright outfit, which is admittedly one of the most effective +in use, takes one horsepower of force for the raising and propulsion of +each 50 pounds of weight. This, for a 25-horsepower engine, would give +a maximum lifting capacity of 1250 pounds. It is doubtful if any of +the higher rated motors have greater efficiency. As an 8-cylinder motor +requires more fuel to operate than a 4-cylinder, it naturally follows +that it is more expensive to run than the smaller motor, and a normal +increase in capacity, taking actual performances as a criterion, is +lacking. In other words, what is the sense of using an 8-cylinder motor +when one of 4 cylinders is sufficient? + +What the Propeller Does. + +Much of the efficiency of the motor is due to the form and gearing of +the propeller. Here again, as in other vital parts of flying-machine +mechanism, we have a wide divergence of opinion as to the best form. A +fish makes progress through the water by using its fins and tail; a +bird makes its way through the air in a similar manner by the use of its +wings and tail. In both instances the motive power comes from the body +of the fish or bird. + +In place of fins or wings the flying machine is equipped with a +propeller, the action of which is furnished by the engine. Fins and +wings have been tried, but they don't work. + +While operating on the same general principle, aerial propellers are +much larger than those used on boats. This is because the boat +propeller has a denser, more substantial medium to work in (water), and +consequently can get a better "hold," and produce more propulsive force +than one of the same size revolving in the air. This necessitates the +aerial propellers being much larger than those employed for marine +purposes. Up to this point all aviators agree, but as to the best form +most of them differ. + +Kinds of Propellers Used. + +One of the most simple is that used by Curtiss. It consists of two +pear-shaped blades of laminated wood, each blade being 5 inches wide +at its extreme point, tapering slightly to the shaft connection. These +blades are joined at the engine shaft, in a direct line. The propeller +has a pitch of 5 feet, and weighs, complete, less than 10 pounds. The +length from end to end of the two blades is 6 1/2 feet. + +Wright uses two wooden propellers, in the rear of his biplane, revolving +in opposite directions. Each propeller is two-bladed. + +Bleriot also uses a two-blade wooden propeller, but it is placed in +front of his machine. The blades are each about 3 1/2 feet long and have +an acute "twist." + +Santos-Dumont uses a two-blade wooden propeller, strikingly similar to +the Bleriot. + +On the Antoinette monoplane, with which good records have been made, the +propeller consists of two spoon-shaped pieces of metal, joined at the +engine shaft in front, and with the concave surfaces facing the machine. + +The propeller on the Voisin biplane is also of metal, consisting of two +aluminum blades connected by a forged steel arm. + +Maximum thrust, or stress--exercise of the greatest air-displacing +force--is the object sought. This, according to experts, is best +obtained with a large propeller diameter and reasonably low speed. The +diameter is the distance from end to end of the blades, which on the +largest propellers ranges from 6 to 8 feet. The larger the blade surface +the greater will be the volume of air displaced, and, following this, +the greater will be the impulse which forces the aeroplane ahead. In all +centrifugal motion there is more or less tendency to disintegration in +the form of "flying off" from the center, and the larger the revolving +object is the stronger is this tendency. This is illustrated in the many +instances in which big grindstones and fly-wheels have burst from being +revolved too fast. To have a propeller break apart in the air would +jeopardize the life of the aviator, and to guard against this it has +been found best to make its revolving action comparatively slow. +Besides this the slow motion (it is only comparatively slow) gives the +atmosphere a chance to refill the area disturbed by one propeller blade, +and thus have a new surface for the next blade to act upon. + +Placing of the Motor. + +As on other points, aviators differ widely in their ideas as to the +proper position for the motor. Wright locates his on the lower plane, +midway between the front and rear edges, but considerably to one side of +the exact center. He then counter-balances the engine weight by placing +his seat far enough away in the opposite direction to preserve the +center of gravity. This leaves a space in the center between the motor +and the operator in which a passenger may be carried without disturbing +the equilibrium. + +Bleriot, on the contrary, has his motor directly in front and preserves +the center of gravity by taking his seat well back, this, with the +weight of the aeroplane, acting as a counter-balance. + +On the Curtiss machine the motor is in the rear, the forward seat of the +operator, and weight of the horizontal rudder and damping plane in front +equalizing the engine weight. + +No Perfect Motor as Yet. + +Engine makers in the United States, England, France and Germany are all +seeking to produce an ideal motor for aviation purposes. Many of the +productions are highly creditable, but it may be truthfully said that +none of them quite fill the bill as regards a combination of the minimum +of weight with the maximum of reliable maintained power. They are all, +in some respects, improvements upon those previously in use, but the +great end sought for has not been fully attained. + +One of the motors thus produced was made by the French firm of Darracq +at the suggestion of Santos Dumont, and on lines laid down by him. +Santos Dumont wanted a 2-cylinder horizontal motor capable of developing +30 horsepower, and not exceeding 4 1/2 pounds per horsepower in weight. + +There can be no question as to the ability and skill of the Darracq +people, or of their desire to produce a motor that would bring new +credit and prominence to the firm. Neither could anything radically +wrong be detected in the plans. But the motor, in at least one important +requirement, fell short of expectations. + +It could not be depended upon to deliver an energy of 30 horsepower +continuously for any length of time. Its maximum power could be secured +only in "spurts." + +This tends to show how hard it is to produce an ideal motor for aviation +purposes. Santos Dumont, of undoubted skill and experience as an +aviator, outlined definitely what he wanted; one of the greatest +designers in the business drew the plans, and the famous house of +Darracq bent its best energies to the production. But the desired end +was not fully attained. + +Features of Darracq Motor. + +Horizontal motors were practically abandoned some time ago in favor of +the vertical type, but Santos Dumont had a logical reason for reverting +to them. He wanted to secure a lower center of gravity than would be +possible with a vertical engine. Theoretically his idea was correct as +the horizontal motor lies flat, and therefore offers less resistance to +the wind, but it did not work out as desired. + +At the same time it must be admitted that this Darracq motor is a marvel +of ingenuity and exquisite workmanship. The two cylinders, having a bore +of 5 1-10 inches and a stroke of 4 7-10 inches, are machined out of a +solid bar of steel until their weight is only 8 4-5 pounds complete. +The head is separate, carrying the seatings for the inlet and exhaust +valves, is screwed onto the cylinder, and then welded in position. A +copper water-jacket is fitted, and it is in this condition that the +weight of 8 4-5 pounds is obtained. + +On long trips, especially in regions where gasolene is hard to get, +the weight of the fuel supply is an important feature in aviation. As a +natural consequence flying machine operators favor the motor of greatest +economy in gasolene consumption, provided it gives the necessary power. + +An American inventor, Ramsey by name, is working on a motor which +is said to possess great possibilities in this line. Its distinctive +features include a connecting rod much shorter than usual, and a crank +shaft located the length of the crank from the central axis of the +cylinder. This has the effect of increasing the piston stroke, and also +of increasing the proportion of the crank circle during which effective +pressure is applied to the crank. + +Making the connecting rod shorter and leaving the crank mechanism the +same would introduce excessive cylinder friction. This Ramsey overcomes +by the location of his crank shaft. The effect of the long piston stroke +thus secured, is to increase the expansion of the gases, which in turn +increases the power of the engine without increasing the amount of fuel +used. + +Propeller Thrust Important. + +There is one great principle in flying machine propulsion which must +not be overlooked. No matter how powerful the engine may be unless the +propeller thrust more than overcomes the wind pressure there can be no +progress forward. Should the force of this propeller thrust and that of +the wind pressure be equal the result is obvious. The machine is at a +stand-still so far as forward progress is concerned and is deprived of +the essential advancing movement. + +Speed not only furnishes sustentation for the airship, but adds to the +stability of the machine. An aeroplane which may be jerky and uncertain +in its movements, so far as equilibrium is concerned, when moving at +a slow gait, will readily maintain an even keel when the speed is +increased. + +Designs for Propeller Blades. + +It is the object of all men who design propellers to obtain the maximum +of thrust with the minimum expenditure of engine energy. With this +purpose in view many peculiar forms of propeller blades have been +evolved. In theory it would seem that the best effects could be secured +with blades so shaped as to present a thin (or cutting) edge when they +come out of the wind, and then at the climax of displacement afford a +maximum of surface so as to displace as much air as possible. While +this is the form most generally favored there are others in successful +operation. + +There is also wide difference in opinion as to the equipment of the +propeller shaft with two or more blades. Some aviators use two and some +four. All have more or less success. As a mathematical proposition it +would seem that four blades should give more propulsive force than two, +but here again comes in one of the puzzles of aviation, as this result +is not always obtained. + +Difference in Propeller Efficiency. + +That there is a great difference in propeller efficiency is made readily +apparent by the comparison of effects produced in two leading makes of +machines--the Wright and the Voisin. + +In the former a weight of from 1,100 to 1,200 pounds is sustained and +advance progress made at the rate of 40 miles an hour and more, with +half the engine speed of a 25 horse-power motor. This would be a +sustaining capacity of 48 pounds per horsepower. But the actual capacity +of the Wright machine, as already stated, is 50 pounds per horsepower. + +The Voisin machine, with aviator, weighs about 1,370 pounds, and is +operated with a so-horsepower motor. Allowing it the same speed as the +Wright we find that, with double the engine energy, the lifting capacity +is only 27 1/2 pounds per horsepower. To what shall we charge this +remarkable difference? The surface of the planes is exactly the same in +both machines so there is no advantage in the matter of supporting area. + +Comparison of Two Designs. + +On the Wright machine two wooden propellers of two blades each (each +blade having a decided "twist") are used. As one 25 horsepower motor +drives both propellers the engine energy amounts to just one-half of +this for each, or 12 1/2 horsepower. And this energy is utilized at +one-half the normal engine speed. + +On the Voisin a radically different system is employed. Here we have +one metal two-bladed propeller with a very slight "twist" to the blade +surfaces. The full energy of a 50-horsepower motor is utilized. + +Experts Fail to Agree. + +Why should there be such a marked difference in the results obtained? +Who knows? Some experts maintain that it is because there are two +propellers on the Wright machine and only one on the Voisin, and +consequently double the propulsive power is exerted. But this is not a +fair deduction, unless both propellers are of the same size. Propulsive +power depends upon the amount of air displaced, and the energy put into +the thrust which displaces the air. + +Other experts argue that the difference in results may be traced to the +difference in blade design, especially in the matter of "twist." + +The fact is that propeller results depend largely upon the nature of +the aeroplanes on which they are used. A propeller, for instance, +which gives excellent results on one type of aeroplane, will not work +satisfactorily on another. + +There are some features, however, which may be safely adopted in +propeller selection. These are: As extensive a diameter as possible; +blade area 10 to 15 per cent of the area swept; pitch four-fifths of +the diameter; rotation slow. The maximum of thrust effort will be thus +obtained. + + + +CHAPTER X. PROPER DIMENSIONS OF MACHINES. + +In laying out plans for a flying machine the first thing to decide upon +is the size of the plane surfaces. The proportions of these must be +based upon the load to be carried. This includes the total weight of +the machine and equipment, and also the operator. This will be a rather +difficult problem to figure out exactly, but practical approximate +figures may be reached. + +It is easy to get at the weight of the operator, motor and propeller, +but the matter of determining, before they are constructed, what the +planes, rudders, auxiliaries, etc., will weigh when completed is an +intricate proposition. The best way is to take the dimensions of some +successful machine and use them, making such alterations in a minor way +as you may desire. + +Dimensions of Leading Machines. + +In the following tables will be found the details as to surface area, +weight, power, etc., of the nine principal types of flying machines +which are now prominently before the public: + + MONOPLANES. + Surface area Spread in Depth in + Make Passengers sq. feet linear feet linear + feet + Santos-Dumont.. 1 110 16.0 26.0 + Bleriot..... 1 150.6 24.6 22.0 + R. E. P..... 1 215 34.1 28.9 + Bleriot..... 2 236 32.9 23.0 + Antoinette.... 2 538 41.2 37.9 + No. of Weight Without + Propeller + Make Cylinders Horse Power Operator + Diameter + Santos-Dumont.. 2 30 250 5.0 + Bleriot..... 3 25 680 6.9 + R. E. P..... 7 35 900 6.6 + Bleriot..... 7 50 1,240 8.1 + Antoinette... 8 50 1,040 7.2 + + BIPLANES. + Surface Area Spread in Depth + in + Make Passengers sq. feet linear feet linear + feet + Curtiss... 2 258 29.0 + 28.7 + Wright.... 2 538 41.0 + 30.7 + Farman.... 2 430 32.9 + 39.6 + Voisin.... 2 538 37.9 + 39.6 + + No. of Weight Without + Propeller + Make Cylinders Horse Power Operator + Diameter + Curtiss... 8 50 600 6.0 + Wright.... 4 25 1,100 8.1 + Farman.... 7 50 1,200 8.9 + Voisin.... 8 50 1,200 6.6 + +In giving the depth dimensions the length over all--from the extreme +edge of the front auxiliary plane to the extreme tip of the rear is +stated. Thus while the dimensions of the main planes of the Wright +machine are 41 feet spread by 6 1/2 feet in depth, the depth over all is +30.7. + +Figuring Out the Details. + +With this data as a guide it should be comparatively easy to decide +upon the dimensions of the machine required. In arriving at the maximum +lifting capacity the weight of the operator must be added. Assuming this +to average 170 pounds the method of procedure would be as follows: + +Add the weight of the operator to the weight of the complete machine. +The new Wright machine complete weighs 900 pounds. This, plus 170, the +weight of the operator, gives a total of 1,070 pounds. There are 538 +square feet of supporting surface, or practically one square foot of +surface area to each two pounds of load. + +There are some machines, notably the Bleriot, in which the supporting +power is much greater. In this latter instance we find a surface area of +150 1/2 square feet carrying a load of 680 plus 170, or an aggregate of +850 pounds. This is the equivalent of five pounds to the square foot. +This ratio is phenomenally large, and should not be taken as a guide by +amateurs. + +The Matter of Passengers. + +These deductions are based on each machine carrying one passenger, which +is admittedly the limit at present of the monoplanes like those operated +for record-making purposes by Santos-Dumont and Bleriot. The biplanes, +however, have a two-passenger capacity, and this adds materially to the +proportion of their weight-sustaining power as compared with the surface +area. In the following statement all the machines are figured on the +one-passenger basis. Curtiss and Wright have carried two passengers on +numerous occasions, and an extra 170 pounds should therefore be added to +the total weight carried, which would materially increase the capacity. +Even with the two-passenger load the limit is by no means reached, +but as experiments have gone no further it is impossible to make more +accurate figures. + +Average Proportions of Load. + +It will be interesting, before proceeding to lay out the dimension +details, to make a comparison of the proportion of load effect with +the supporting surfaces of various well-known machines. Here are the +figures: + +Santos-Dumont--A trifle under four pounds per square foot. + +Bleriot--Five pounds. + +R. E. P.--Five pounds. + +Antoinette--About two and one-quarter pounds. + +Curtiss--About two and one-half pounds. + +Wright--Two and one-quarter pounds. + +Farman--A trifle over three pounds. + +Voisin--A little under two and one-half pounds. + +Importance of Engine Power. + +While these figures are authentic, they are in a way misleading, as the +important factor of engine power is not taken into consideration. Let us +recall the fact that it is the engine power which keeps the machine in +motion, and that it is only while in motion that the machine will remain +suspended in the air. Hence, to attribute the support solely to the +surface area is erroneous. True, that once under headway the planes +contribute largely to the sustaining effect, and are absolutely +essential in aerial navigation--the motor could not rise without +them--still, when it comes to a question of weight-sustaining power, we +must also figure on the engine capacity. + +In the Wright machine, in which there is a lifting capacity of +approximately 2 1/4 pounds to the square foot of surface area, an engine +of only 25 horsepower is used. In the Curtiss, which has a lifting +capacity of 2 1/2 pounds per square foot, the engine is of 50 +horsepower. This is another of the peculiarities of aerial construction +and navigation. Here we have a gain of 1/4 pound in weight-lifting +capacity with an expenditure of double the horsepower. It is this +feature which enables Curtiss to get along with a smaller surface area +of supporting planes at the expense of a big increase in engine power. +Proper Weight of Machine. + +As a general proposition the most satisfactory machine for amateur +purposes will be found to be one with a total weight-sustaining power of +about 1,200 pounds. Deducting 170 pounds as the weight of the operator, +this will leave 1,030 pounds for the complete motor-equipped machine, +and it should be easy to construct one within this limit. This implies, +of course, that due care will be taken to eliminate all superfluous +weight by using the lightest material compatible with strength and +safety. + +This plan will admit of 686 pounds weight in the frame work, coverings, +etc., and 344 for the motor, propeller, etc., which will be ample. Just +how to distribute the weight of the planes is a matter which must be +left to the ingenuity of the builder. + +Comparison of Bird Power. + +There is an interesting study in the accompanying illustration. Note +that the surface area of the albatross is much smaller than that of the +vulture, although the wing spread is about the same. Despite this the +albatross accomplishes fully as much in the way of flight and soaring as +the vulture. Why? Because the albaboss is quicker and more powerful in +action. It is the application of this same principle in flying machines +which enables those of great speed and power to get along with less +supporting surface than those of slower movement. + +Measurements of Curtiss Machine. + +Some idea of framework proportion may be had from the following +description of the Curtiss machine. The main planes have a spread +(width) of 29 feet, and are 4 1/2 feet deep. The front double surface +horizontal rudder is 6x2 feet, with an area of 24 square feet. To the +rear of the main planes is a single surface horizontal plane 6x2 feet, +with an area of 12 square feet. In connection with this is a vertical +rudder 2 1/2 feet square. Two movable ailerons, or balancing planes, are +placed at the extreme ends of the upper planes. These are 6x2 feet, +and have a combined area of 24 square feet. There is also a triangular +shaped vertical steadying surface in connection with the front rudder. + +Thus we have a total of 195 square feet, but as the official figures are +258, and the size of the triangular-shaped steadying surface is unknown, +we must take it for granted that this makes up the difference. In +the matter of proportion the horizontal double-plane rudder is about +one-tenth the size of the main plane, counting the surface area of +only one plane, the vertical rudder one-fortieth, and the ailerons +one-twentieth. + + + +CHAPTER XI. PLANE AND RUDDER CONTROL. + +Having constructed and equipped your machine, the next thing is to +decide upon the method of controlling the various rudders and auxiliary +planes by which the direction and equilibrium and ascending and +descending of the machine are governed. + +The operator must be in position to shift instantaneously the position +of rudders and planes, and also to control the action of the motor. This +latter is supposed to work automatically and as a general thing does +so with entire satisfaction, but there are times when the supply of +gasolene must be regulated, and similar things done. Airship navigation +calls for quick action, and for this reason the matter of control is an +important one--it is more than important; it is vital. + +Several Methods of Control. + +Some aviators use a steering wheel somewhat after the style of that used +in automobiles, and by this not only manipulate the rudder planes, but +also the flow of gasolene. Others employ foot levers, and still others, +like the Wrights, depend upon hand levers. + +Curtiss steers his aeroplane by means of a wheel, but secures the +desired stabilizing effect with an ingenious jointed chair-back. This is +so arranged that by leaning toward the high point of his wing planes the +aeroplane is restored to an even keel. The steering post of the wheel is +movable backward and forward, and by this motion elevation is obtained. + +The Wrights for some time used two hand levers, one to steer by and warp +the flexible tips of the planes, the other to secure elevation. They +have now consolidated all the functions in one lever. Bleriot also uses +the single lever control. + +Farman employs a lever to actuate the rudders, but manipulates the +balancing planes by foot levers. + +Santos-Dumont uses two hand levers with which to steer and elevate, +but manipulates the planes by means of an attachment to the back of his +outer coat. + +Connection With the Levers. + +No matter which particular method is employed, the connection between +the levers and the object to be manipulated is almost invariably by +wire. For instance, from the steering levers (or lever) two wires +connect with opposite sides of the rudder. As a lever is moved so as to +draw in the right-hand wire the rudder is drawn to the right and vice +versa. The operation is exactly the same as in steering a boat. It +is the same way in changing the position of the balancing planes. A +movement of the hands or feet and the machine has changed its course, +or, if the equilibrium is threatened, is back on an even keel. + +Simple as this seems it calls for a cool head, quick eye, and steady +hand. The least hesitation or a false movement, and both aviator and +craft are in danger. + +Which Method is Best? + +It would be a bold man who would attempt to pick out any one of these +methods of control and say it was better than the others. As in other +sections of aeroplane mechanism each method has its advocates who dwell +learnedly upon its advantages, but the fact remains that all the various +plans work well and give satisfaction. + +What the novice is interested in knowing is how the control is effected, +and whether he has become proficient enough in his manipulation of it to +be absolutely dependable in time of emergency. No amateur should attempt +a flight alone, until he has thoroughly mastered the steering and plane +control. If the services and advice of an experienced aviator are not to +be had the novice should mount his machine on some suitable supports so +it will be well clear of the ground, and, getting into the operator's +seat, proceed to make himself well acquainted with the operation of the +steering wheel and levers. + +Some Things to Be Learned. + +He will soon learn that certain movements of the steering gear produce +certain effects on the rudders. If, for instance, his machine is +equipped with a steering wheel, he will find that turning the wheel to +the right turns the aeroplane in the same direction, because the tiller +is brought around to the left. In the same way he will learn that a +given movement of the lever throws the forward edge of the main plane +upward, and that the machine, getting the impetus of the wind under the +concave surfaces of the planes, will ascend. In the same way it will +quickly become apparent to him that an opposite movement of the lever +will produce an opposite effect--the forward edges of the planes will be +lowered, the air will be "spilled" out to the rear, and the machine will +descend. + +The time expended in these preliminary lessons will be well spent. It +would be an act of folly to attempt to actually sail the craft without +them. + + + +CHAPTER XII. HOW TO USE THE MACHINE. + +It is a mistaken idea that flying machines must be operated at extreme +altitudes. True, under the impetus of handsome prizes, and the incentive +to advance scientific knowledge, professional aviators have ascended to +considerable heights, flights at from 500 to 1,500 feet being now +common with such experts as Farman, Bleriot, Latham, Paulhan, Wright and +Curtiss. The altitude record at this time is about 4,165 feet, held by +Paulhan. + +One of the instructions given by experienced aviators to pupils, and for +which they insist upon implicit obeyance, is: "If your machine gets more +than 30 feet high, or comes closer to the ground than 6 feet, descend at +once." Such men as Wright and Curtiss will not tolerate a violation of +this rule. If their instructions are not strictly complied with they +decline to give the offender further lessons. + +Why This Rule Prevails. + +There is good reason for this precaution. The higher the altitude the +more rarefied (thinner) becomes the air, and the less sustaining power +it has. Consequently the more difficult it becomes to keep in suspension +a given weight. When sailing within 30 feet of the ground sustentation +is comparatively easy and, should a fall occur, the results are not +likely to be serious. On the other hand, sailing too near the ground +is almost as objectionable in many ways as getting up too high. If the +craft is navigated too close to the ground trees, shrubs, fences and +other obstructions are liable to be encountered. There is also the +handicap of contrary air currents diverted by the obstructions referred +to, and which will be explained more fully further on. + +How to Make a Start. + +Taking it for granted that the beginner has familiarized himself with +the manipulation of the machine, and especially the control mechanism, +the next thing in order is an actual flight. It is probable that his +machine will be equipped with a wheeled alighting gear, as the skids +used by the Wrights necessitate the use of a special starting track. +In this respect the wheeled machine is much easier to handle so far as +novices are concerned as it may be easily rolled to the trial grounds. +This, as in the case of the initial experiments, should be a clear, +reasonably level place, free from trees, fences, rocks and similar +obstructions with which there may be danger of colliding. + +The beginner will need the assistance of three men. One of these should +take his position in the rear of the machine, and one at each end. On +reaching the trial ground the aviator takes his seat in the machine and, +while the men at the ends hold it steady the one in the rear assists in +retaining it until the operator is ready. In the meantime the aviator +has started his motor. Like the glider the flying machine, in order to +accomplish the desired results, should be headed into the wind. + +When the Machine Rises. + +Under the impulse of the pushing movement, and assisted by the motor +action, the machine will gradually rise from the ground--provided it +has been properly proportioned and put together, and everything is in +working order. This is the time when the aviator requires a cool head, +At a modest distance from the ground use the control lever to bring the +machine on a horizontal level and overcome the tendency to rise. The +exact manipulation of this lever depends upon the method of control +adopted, and with this the aviator is supposed to have thoroughly +familiarized himself as previously advised in Chapter XI. + +It is at this juncture that the operator must act promptly, but with the +perfect composure begotten of confidence. One of the great drawbacks in +aviation by novices is the tendency to become rattled, and this is much +more prevalent than one might suppose, even among men who, under other +conditions, are cool and confident in their actions. + +There is something in the sensation of being suddenly lifted from the +ground, and suspended in the air that is disconcerting at the start, +but this will soon wear off if the experimenter will keep cool. A few +successful flights no matter how short they may be, will put a lot of +confidence into him. + +Make Your Flights Short. + +Be modest in your initial flights. Don't attempt to match the records +of experienced men who have devoted years to mastering the details of +aviation. Paulhan, Farman, Bleriot, Wright, Curtiss, and all the rest of +them began, and practiced for years, in the manner here described, being +content to make just a little advancement at each attempt. A flight of +150 feet, cleanly and safely made, is better as a beginning than one of +400 yards full of bungling mishaps. + +And yet these latter have their uses, provided the operator is of a +discerning mind and can take advantage of them as object lessons. But, +it is not well to invite them. They will occur frequently enough under +the most favorable conditions, and it is best to have them come later +when the feeling of trepidation and uncertainty as to what to do has +worn off. + +Above all, don't attempt to fly too high. Keep within a reasonable +distance from the ground--about 25 or 30 feet. This advice is not given +solely to lessen the risk of serious accident in case of collapse, but +mainly because it will assist to instill confidence in the operator. + +It is comparatively easy to learn to swim in shallow water, but the +knowledge that one is tempting death in deep water begets timidity. + +Preserving the Equilibrium. + +After learning how to start and stop, to ascend and descend, the next +thing to master is the art of preserving equilibrium, the knack of +keeping the machine perfectly level in the air--on an "even keel," as +a sailor would say. This simile is particularly appropriate as all +aviators are in reality sailors, and much more daring ones than those +who course the seas. The latter are in craft which are kept afloat by +the buoyancy of the water, whether in motion or otherwise and, so long +as normal conditions prevail, will not sink. Aviators sail the air in +craft in which constant motion must be maintained in order to ensure +flotation. + +The man who has ridden a bicycle or motorcycle around curves at anything +like high speed, will have a very good idea as to the principle of +maintaining equilibrium in an airship. He knows that in rounding curves +rapidly there is a marked tendency to change the direction of the motion +which will result in an upset unless he overcomes it by an inclination +of his body in an opposite direction. This is why we see racers lean +well over when taking the curves. It simply must be done to preserve the +equilibrium and avoid a spill. + +How It Works In the Air. + +If the equilibrium of an airship is disturbed to an extent which +completely overcomes the center of gravity it falls according to the +location of the displacement. If this displacement, for instance, is at +either end the apparatus falls endways; if it is to the front or rear, +the fall is in the corresponding direction. + +Owing to uncertain air currents--the air is continually shifting and +eddying, especially within a hundred feet or so of the earth--the +equilibrium of an airship is almost constantly being disturbed to some +extent. Even if this disturbance is not serious enough to bring on +a fall it interferes with the progress of the machine, and should +be overcome at once. This is one of the things connected with aerial +navigation which calls for prompt, intelligent action. + +Frequently, when the displacement is very slight, it may be overcome, +and the craft immediately righted by a mere shifting of the operator's +body. Take, for illustration, a case in which the extreme right end +of the machine becomes lowered a trifle from the normal level. It is +possible to bring it back into proper position by leaning over to the +left far enough to shift the weight to the counter-balancing point. The +same holds good as to minor front or rear displacements. + +When Planes Must Be Used. + +There are other displacements, however, and these are the most frequent, +which can be only overcome by manipulation of the stabilizing planes. +The method of procedure depends upon the form of machine in use. The +Wright machine, as previously explained, is equipped with plane ends +which are so contrived as to admit of their being warped (position +changed) by means of the lever control. These flexible tip planes move +simultaneously, but in opposite directions. As those on one end rise, +those on the other end fall below the level of the main plane. By this +means air is displaced at one point, and an increased amount secured in +another. + +This may seem like a complicated system, but its workings are simple +when once understood. It is by the manipulation or warping of these +flexible tips that transverse stability is maintained, and any tendency +to displacement endways is overcome. Longitudinal stability is governed +by means of the front rudder. + +Stabilizing planes of some form are a feature, and a necessary feature, +on all flying machines, but the methods of application and manipulation +vary according to the individual ideas of the inventors. They all tend, +however, toward the same end--the keeping of the machine perfectly level +when being navigated in the air. + +When to Make a Flight. + +A beginner should never attempt to make a flight when a strong wind is +blowing. The fiercer the wind, the more likely it is to be gusty and +uncertain, and the more difficult it will be to control the machine. +Even the most experienced and daring of aviators find there is a limit +to wind speed against which they dare not compete. This is not because +they lack courage, but have the sense to realize that it would be silly +and useless. + +The novice will find a comparatively still day, or one when the wind is +blowing at not to exceed 15 miles an hour, the best for his experiments. +The machine will be more easily controlled, the trip will be safer, and +also cheaper as the consumption of fuel increases with the speed of the +wind against which the aeroplane is forced. + + + +CHAPTER XIII. PECULIARITIES OF AIRSHIP POWER. + +As a general proposition it takes much more power to propel an airship +a given number of miles in a certain time than it does an automobile +carrying a far heavier load. Automobiles with a gross load of 4,000 +pounds, and equipped with engines of 30 horsepower, have travelled +considerable distances at the rate of 50 miles an hour. This is an +equivalent of about 134 pounds per horsepower. For an average modern +flying machine, with a total load, machine and passengers, of 1,200 +pounds, and equipped with a 50-horsepower engine, 50 miles an hour +is the maximum. Here we have the equivalent of exactly 24 pounds per +horsepower. Why this great difference? + +No less an authority than Mr. Octave Chanute answers the question in a +plain, easily understood manner. He says: + +"In the case of an automobile the ground furnishes a stable support; +in the case of a flying machine the engine must furnish the support and +also velocity by which the apparatus is sustained in the air." + +Pressure of the Wind. + +Air pressure is a big factor in the matter of aeroplane horsepower. +Allowing that a dead calm exists, a body moving in the atmosphere +creates more or less resistance. The faster it moves, the greater is +this resistance. Moving at the rate of 60 miles an hour the resistance, +or wind pressure, is approximately 50 pounds to the square foot of +surface presented. If the moving object is advancing at a right angle +to the wind the following table will give the horsepower effect of the +resistance per square foot of surface at various speeds. + + Horse Power + Miles per Hour per sq. foot + 10 0.013 + 15 0 044 + 20 0.105 + 25 0.205 + 30 0.354 + 40 0.84 + 50 1.64 + 60 2.83 + 80 6.72 + 100 13.12 + +While the pressure per square foot at 60 miles an hour, is only 1.64 +horsepower, at 100 miles, less than double the speed, it has increased +to 13.12 horsepower, or exactly eight times as much. In other words the +pressure of the wind increases with the square of the velocity. Wind at +10 miles an hour has four times more pressure than wind at 5 miles an +hour. + +How to Determine Upon Power. + +This element of air resistance must be taken into consideration in +determining the engine horsepower required. When the machine is under +headway sufficient to raise it from the ground (about 20 miles an hour), +each square foot of surface resistance, will require nearly nine-tenths +of a horsepower to overcome the wind pressure, and propel the machine +through the air. As shown in the table the ratio of power required +increases rapidly as the speed increases until at 60 miles an hour +approximately 3 horsepower is needed. + +In a machine like the Curtiss the area of wind-exposed surface is about +15 square feet. On the basis of this resistance moving the machine at 40 +miles an hour would require 12 horsepower. This computation covers only +the machine's power to overcome resistance. It does not cover the power +exerted in propelling the machine forward after the air pressure is +overcome. To meet this important requirement Mr. Curtiss finds it +necessary to use a 50-horsepower engine. Of this power, as has been +already stated, 12 horsepower is consumed in meeting the wind pressure, +leaving 38 horsepower for the purpose of making progress. + +The flying machine must move faster than the air to which it is opposed. +Unless it does this there can be no direct progress. If the two forces +are equal there is no straight-ahead advancement. Take, for sake of +illustration, a case in which an aeroplane, which has developed a speed +of 30 miles an hour, meets a wind velocity of equal force moving in an +opposite direction. What is the result? There can be no advance because +it is a contest between two evenly matched forces. The aeroplane stands +still. The only way to get out of the difficulty is for the operator to +wait for more favorable conditions, or bring his machine to the ground +in the usual manner by manipulation of the control system. + +Take another case. An aeroplane, capable of making 50 miles an hour in a +calm, is met by a head wind of 25 miles an hour. How much progress does +the aeroplane make? Obviously it is 25 miles an hour over the ground. + +Put the proposition in still another way. If the wind is blowing harder +than it is possible for the engine power to overcome, the machine will +be forced backward. + +Wind Pressure a Necessity. + +While all this is true, the fact remains that wind pressure, up to +a certain stage, is an absolute necessity in aerial navigation. The +atmosphere itself has very little real supporting power, especially if +inactive. If a body heavier than air is to remain afloat it must move +rapidly while in suspension. + +One of the best illustrations of this is to be found in skating over +thin ice. Every school boy knows that if he moves with speed he may +skate or glide in safety across a thin sheet of ice that would not +begin to bear his weight if he were standing still. Exactly the same +proposition obtains in the case of the flying machine. + +The non-technical reason why the support of the machine becomes easier +as the speed increases is that the sustaining power of the atmosphere +increases with the resistance, and the speed with which the object is +moving increases this resistance. With a velocity of 12 miles an hour +the weight of the machine is practically reduced by 230 pounds. Thus, if +under a condition of absolute calm it were possible to sustain a weight +of 770 pounds, the same atmosphere would sustain a weight of 1,000 +pounds moving at a speed of 12 miles an hour. This sustaining power +increases rapidly as the speed increases. While at 12 miles the +sustaining power is figured at 230 pounds, at 24 miles it is four times +as great, or 920 pounds. + +Supporting Area of Birds. + +One of the things which all producing aviators seek to copy is the +motive power of birds, particularly in their relation to the area of +support. Close investigation has established the fact that the larger +the bird the less is the relative area of support required to secure a +given result. This is shown in the following table: + + Supporting + Weight Surface Horse area + Bird in lbs. in sq. feet power per lb. + Pigeon 1.00 0.7 0.012 0.7 + Wild Goose 9.00 2.65 0.026 0.2833 + Buzzard 5.00 5.03 0.015 1.06 + Condor 17.00 9.85 0.043 0.57 + +So far as known the condor is the largest of modern birds. It has a wing +stretch of 10 feet from tip to tip, a supporting area of about 10 square +feet, and weighs 17 pounds. It. is capable of exerting perhaps 1-30 +horsepower. (These figures are, of course, approximate.) Comparing the +condor with the buzzard with a wing stretch of 6 feet, supporting area +of 5 square feet, and a little over 1-100 horsepower, it may be seen +that, broadly speaking, the larger the bird the less surface area +(relatively) is needed for its support in the air. + +Comparison With Aeroplanes. + +If we compare the bird figures with those made possible by the +development of the aeroplane it will be readily seen that man has made a +wonderful advance in imitating the results produced by nature. Here are +the figures: + + Supporting + Weight Surface Horse area + Machine in lbs. in sq. feet power per lb. + Santos-Dumont.. 350 110.00 30 0.314 + Bleriot..... 700 150.00 25 0.214 + Antoinette.... 1,200 538.00 50 0.448 + Curtiss..... 700 258.00 60 0.368 + Wright.....[4] 1,100 538.00 25 0.489 + Farman...... 1,200 430.00 50 0.358 + Voisin...... 1,200 538.00 50 0.448 + +While the average supporting surface is in favor of the aeroplane, this +is more than overbalanced by the greater amount of horsepower required +for the weight lifted. The average supporting surface in birds is about +three-quarters of a square foot per pound. In the average aeroplane it +is about one-half square foot per pound. On the other hand the average +aeroplane has a lifting capacity of 24 pounds per horsepower, while the +buzzard, for instance, lifts 5 pounds with 15-100 of a horsepower. +If the Wright machine--which has a lifting power of 50 pounds per +horsepower--should be alone considered the showing would be much more +favorable to the aeroplane, but it would not be a fair comparison. + +More Surface, Less Power. + +Broadly speaking, the larger the supporting area the less will be the +power required. Wright, by the use of 538 square feet of supporting +surface, gets along with an engine of 25 horsepower. Curtiss, who uses +only 258 square feet of surface, finds an engine of 50 horsepower is +needed. Other things, such as frame, etc., being equal, it stands +to reason that a reduction in the area of supporting surface will +correspondingly reduce the weight of the machine. Thus we have the +Curtiss machine with its 258 square feet of surface, weighing only 600 +pounds (without operator), but requiring double the horsepower of +the Wright machine with 538 square feet of surface and weighing 1,100 +pounds. This demonstrates in a forceful way the proposition that the +larger the surface the less power will be needed. + +But there is a limit, on account of its bulk and awkwardness in +handling, beyond which the surface area cannot be enlarged. Otherwise +it might be possible to equip and operate aeroplanes satisfactorily with +engines of 15 horsepower, or even less. + +The Fuel Consumption Problem. + +Fuel consumption is a prime factor in the production of engine power. +The veriest mechanical tyro knows in a general way that the more power +is secured the more fuel must be consumed, allowing that there is no +difference in the power-producing qualities of the material used. But +few of us understand just what the ratio of increase is, or how it is +caused. This proposition is one of keen interest in connection with +aviation. + +Let us cite a problem which will illustrate the point quoted: Allowing +that it takes a given amount of gasolene to propel a flying machine a +given distance, half the way with the wind, and half against it, the +wind blowing at one-half the speed of the machine, what will be the +increase in fuel consumption? + +Increase of Thirty Per Cent. + +On the face of it there would seem to be no call for an increase as the +resistance met when going against the wind is apparently offset by the +propulsive force of the wind when the machine is travelling with +it. This, however, is called faulty reasoning. The increase in fuel +consumption, as figured by Mr. F. W. Lanchester, of the Royal Society of +Arts, will be fully 30 per cent over the amount required for a similar +operation of the machine in still air. If the journey should be made at +right angles to the wind under the same conditions the increase would be +15 per cent. + +In other words Mr. Lanchester maintains that the work done by the motor +in making headway against the wind for a certain distance calls for more +engine energy, and consequently more fuel by 30 per cent, than is saved +by the helping force of the wind on the return journey. + + + +CHAPTER XIV. ABOUT WIND CURRENTS, ETC. + +One of the first difficulties which the novice will encounter is the +uncertainty of the wind currents. With a low velocity the wind, some +distance away from the ground, is ordinarily steady. As the velocity +increases, however, the wind generally becomes gusty and fitful in its +action. This, it should be remembered, does not refer to the velocity of +the machine, but to that of the air itself. + +In this connection Mr. Arthur T. Atherholt, president of the Aero +Club of Pennsylvania, in addressing the Boston Society of Scientific +Research, said: + +"Probably the whirlpools of Niagara contain no more erratic currents +than the strata of air which is now immediately above us, a fact hard to +realize on account of its invisibility." + +Changes In Wind Currents. + +While Mr. Atherholt's experience has been mainly with balloons it is all +the more valuable on this account, as the balloons were at the mercy of +the wind and their varying directions afforded an indisputable guide as +to the changing course of the air currents. In speaking of this he said: + +"In the many trips taken, varying in distance traversed from twenty-five +to 900 miles, it was never possible except in one instance to maintain +a straight course. These uncertain currents were most noticeable in +the Gordon-Bennett race from St. Louis in 1907. Of the nine aerostats +competing in that event, eight covered a more or less direct course +due east and southeast, whereas the writer, with Major Henry B. Hersey, +first started northwest, then north, northeast, east, east by south, +and when over the center of Lake Erie were again blown northwest +notwithstanding that more favorable winds were sought for at altitudes +varying from 100 to 3,000 meters, necessitating a finish in Canada +nearly northeast of the starting point. + +"These nine balloons, making landings extending from Lake Ontario, +Canada, to Virginia, all started from one point within the same hour. + +"The single exception to these roving currents occurred on October 21st, +of last year (1909) when, starting from Philadelphia, the wind shifted +more than eight degrees, the greatest variation being at the lowest +altitudes, yet at no time was a height of over a mile reached. + +"Throughout the entire day the sky was overcast, with a thermometer +varying from fifty-seven degrees at 300 feet to forty-four degrees, +Fahrenheit at 5,000 feet, at which altitude the wind had a velocity of +43 miles an hour, in clouds of a cirro-cumulus nature, a landing finally +being made near Tannersville, New York, in the Catskill mountains, after +a voyage of five and one-half hours. + +"I have no knowledge of a recorded trip of this distance and duration, +maintained in practically a straight line from start to finish." + +This wind disturbance is more noticeable and more difficult to contend +with in a balloon than in a flying machine, owing to the bulk and +unwieldy character of the former. At the same time it is not conducive +to pleasant, safe or satisfactory sky-sailing in an aeroplane. This is +not stated with the purpose of discouraging aviation, but merely that +the operator may know what to expect and be prepared to meet it. + +Not only does the wind change its horizontal course abruptly and without +notice, but it also shifts in a vertical direction, one second blowing +up, and another down. No man has as yet fathomed the why and wherefore +of this erratic action; it is only known that it exists. + +The most stable currents will be found from 50 to 100 feet from the +earth, provided the wind is not diverted by such objects as trees, +rocks, etc. That there are equally stable currents higher up is true, +but they are generally to be found at excessive altitudes. + +How a Bird Meets Currents. + +Observe a bird in action on a windy day and you will find it continually +changing the position of its wings. This is done to meet the varying +gusts and eddies of the air so that sustentation may be maintained and +headway made. One second the bird is bending its wings, altering the +angle of incidence; the next it is lifting or depressing one wing at a +time. Still again it will extend one wing tip in advance of the other, +or be spreading or folding, lowering or raising its tail. + +All these motions have a meaning, a purpose. They assist the bird in +preserving its equilibrium. Without them the bird would be just as +helpless in the air as a human being and could not remain afloat. + +When the wind is still, or comparatively so, a bird, having secured the +desired altitude by flight at an angle, may sail or soar with no wing +action beyond an occasional stroke when it desires to advance. But, in a +gusty, uncertain wind it must use its wings or alight somewhere. + +Trying to Imitate the Bird. + +Writing in _Fly_, Mr. William E. White says: + +"The bird's flight suggests a number of ways in which the equilibrium +of a mechanical bird may be controlled. Each of these methods of control +may be effected by several different forms of mechanism. + +"Placing the two wings of an aeroplane at an angle of three to five +degrees to each other is perhaps the oldest way of securing lateral +balance. This way readily occurs to anyone who watches a sea gull +soaring. The theory of the dihedral angle is that when one wing is +lifted by a gust of wind, the air is spilled from under it; while +the other wing, being correspondingly depressed, presents a greater +resistance to the gust and is lifted restoring the balance. A fixed +angle of three to five degrees, however, will only be sufficient for +very light puffs of wind and to mount the wings so that the whole +wing may be moved to change the dihedral angle presents mechanical +difficulties which would be better avoided. + +"The objection of mechanical impracticability applies to any plan +to preserve the balance by shifting weight or ballast. The center of +gravity should be lower than the center of the supporting surfaces, +but cannot be made much lower. It is a common mistake to assume that +complete stability will be secured by hanging the center of gravity very +low on the principle of the parachute. An aeroplane depends upon rapid +horizontal motion for its support, and if the center of gravity be far +below the center of support, every change of speed or wind pressure will +cause the machine to turn about its center of gravity, pitching forward +and backward dangerously. + +Preserving Longitudinal Balance. + +"The birds maintain longitudinal, or fore and aft balance, by elevating +or depressing their tails. Whether this action is secured in an +aeroplane by means of a horizontal rudder placed in the rear, or by +deflecting planes placed in front of the main planes, the principle is +evidently the same. A horizontal rudder placed well to the rear as in +the Antoinette, Bleriot or Santos-Dumont monoplanes, will be very much +safer and steadier than the deflecting planes in front, as in the Wright +or Curtiss biplanes, but not so sensitive or prompt in action. + +"The natural fore and aft stability is very much strengthened by placing +the load well forward. The center of gravity near the front and a +tail or rudder streaming to the rear secures stability as an arrow is +balanced by the head and feathering. The adoption of this principle +makes it almost impossible for the aeroplane to turn over. + +The Matter of Lateral Balance. + +"All successful aeroplanes thus far have maintained lateral balance by +the principle of changing the angle of incidence of the wings. + +"Other ways of maintaining the lateral balance, suggested by observation +of the flight of birds are--extending the wing tips and spilling the air +through the pinions; or, what is the same thing, varying the area of the +wings at their extremities. + +"Extending the wing tips seems to be a simple and effective solution of +the problem. The tips may be made to swing outward upon a vertical axis +placed at the front edge of the main planes; or they may be hinged to +the ends of the main plane so as to be elevated or depressed through +suitable connections by the aviator; or they may be supported from a +horizontal axis parallel with the ends of the main planes so that they +may swing outward, the aviator controlling both tips through one lever +so that as one tip is extended the other is retracted. + +"The elastic wing pinions of a bird bend easily before the wind, +permitting the gusts to glance off, but presenting always an even and +efficient curvature to the steady currents of the air." + +High Winds Threaten Stability. + +To ensure perfect stability, without control, either human or automatic, +it is asserted that the aeroplane must move faster than the wind is +blowing. So long as the wind is blowing at the rate of 30 miles an hour, +and the machine is traveling 40 or more, there will be little trouble as +regards equilibrium so far as wind disturbance goes, provided the wind +blows evenly and does not come in gusts or eddying currents. But when +conditions are reversed--when the machine travels only 30 miles an hour +and the wind blows at the rate of 50, look out for loss of equilibrium. + +One of the main reasons for this is that high winds are rarely steady; +they seldom blow for any length of time at the same speed. They are +usually "gusty," the gusts being a momentary movement at a higher speed. +Tornadic gusts are also formed by the meeting of two opposing currents, +causing a whirling motion, which makes stability uncertain. Besides, it +is not unusual for wind of high speed to suddenly change its direction +without warning. + +Trouble With Vertical Columns. + +Vertical currents--columns of ascending air--are frequently encountered +in unexpected places and have more or less tendency, according to their +strength, to make it difficult to keep the machine within a reasonable +distance from the ground. + +These vertical currents are most generally noticeable in the vicinity +of steep cliffs, or deep ravines. In such instances they are usually of +considerable strength, being caused by the deflection of strong winds +blowing against the face of the cliffs. This deflection exerts a back +pressure which is felt quite a distance away from the point of origin, +so that the vertical current exerts an influence in forcing the machine +upward long before the cliff is reached. + + + +CHAPTER XV. THE ELEMENT OF DANGER. + +That there is an element of danger in aviation is undeniable, but it is +nowhere so great as the public imagines. Men are killed and injured in +the operation of flying machines just as they are killed and injured +in the operation of railways. Considering the character of aviation the +percentage of casualties is surprisingly small. + +This is because the results following a collapse in the air are very +much different from what might be imagined. Instead of dropping to the +ground like a bullet an aeroplane, under ordinary conditions will, when +anything goes wrong, sail gently downward like a parachute, particularly +if the operator is cool-headed and nervy enough to so manipulate the +apparatus as to preserve its equilibrium and keep the machine on an even +keel. + +Two Fields of Safety. + +At least one prominent aviator has declared that there are two fields +of safety--one close to the ground, and the other well up in the air. In +the first-named the fall will be a slight one with little chance of the +operator being seriously hurt. From the field of high altitude the the +descent will be gradual, as a rule, the planes of the machine serving to +break the force of the fall. With a cool-headed operator in control the +aeroplane may be even guided at an angle (about 1 to 8) in its descent +so as to touch the ground with a gliding motion and with a minimum of +impact. + +Such an experience, of course, is far from pleasant, but it is by no +means so dangerous as might appear. There is more real danger in falling +from an elevation of 75 or 100 feet than there is from 1,000 feet, as +in the former case there is no chance for the machine to serve as a +parachute--its contact with the ground comes too quickly. + +Lesson in Recent Accidents. + +Among the more recent fatalities in aviation are the deaths of Antonio +Fernandez and Leon Delagrange. The former was thrown to the ground by a +sudden stoppage of his motor, the entire machine seeming to collapse. It +is evident there were radical defects, not only in the motor, but in the +aeroplane framework as well. At the time of the stoppage it is +estimated that Fernandez was up about 1,500 feet, but the machine got +no opportunity to exert a parachute effect, as it broke up immediately. +This would indicate a fatal weakness in the structure which, under +proper testing, could probably have been detected before it was used in +flight. + +It is hard to say it, but Delagrange appears to have been culpable to +great degree in overloading his machine with a motor equipment much +heavier than it was designed to sustain. He was 65 feet up in the air +when the collapse occurred, resulting in his death. As in the case of +Fernandez common-sense precaution would doubtless have prevented the +fatality. + +Aviation Not Extra Hazardous. + +All told there have been, up to the time of this writing (April, 1910), +just five fatalities in the history of power-driven aviation. This is +surprisingly low when the nature of the experiments, and the fact that +most of the operators were far from having extended experience, is taken +into consideration. Men like the Wrights, Curtiss, Bleriot, Farman, +Paulhan and others, are now experts, but there was a time, and it was +not long ago, when they were unskilled. That they, with numerous +others less widely known, should have come safely through their many +experiments would seem to disprove the prevailing idea that aviation is +an extra hazardous pursuit. + +In the hands of careful, quick-witted, nervy men the sailing of an +airship should be no more hazardous than the sailing of a yacht. A +vessel captain with common sense will not go to sea in a storm, or +navigate a weak, unseaworthy craft. Neither should an aviator attempt to +sail when the wind is high and gusty, nor with a machine which has not +been thoroughly tested and found to be strong and safe. + +Safer Than Railroading. + +Statistics show that some 12,000 people are killed and 72,000 injured +every year on the railroads of the United States. Come to think it over +it is small wonder that the list of fatalities is so large. Trains +are run at high speeds, dashing over crossings at which collisions are +liable to occur, and over bridges which often collapse or are swept away +by floods. Still, while the number of casualties is large, the actual +percentage is small considering the immense number of people involved. + +It is so in aviation. The number of casualties is remarkably small in +comparison with the number of flights made. In the hands of competent +men the sailing of an airship should be, and is, freer from risk of +accident than the running of a railway train. There are no rails +to spread or break, no bridges to collapse, no crossings at which +collisions may occur, no chance for some sleepy or overworked employee +to misunderstand the dispatcher's orders and cause a wreck. + +Two Main Causes of Trouble. + +The two main causes of trouble in an airship leading to disaster may +be attributed to the stoppage of the motor, and the aviator becoming +rattled so that he loses control of his machine. Modern ingenuity is +fast developing motors that almost daily become more and more reliable, +and experience is making aviators more and more self-confident in their +ability to act wisely and promptly in cases of emergency. Besides this +a satisfactory system of automatic control is in a fair way of being +perfected. + +Occasionally even the most experienced and competent of men in all +callings become careless and by foolish action invite disaster. This +is true of aviators the same as it is of railroaders, men who work in +dynamite mills, etc. But in nearly every instance the responsibility +rests with the individual; not with the system. There are some men +unfitted by nature for aviation, just as there are others unfitted to be +railway engineers. + + + +CHAPTER XVI. RADICAL CHANGES BEING MADE. + +Changes, many of them extremely radical in their nature, are continually +being made by prominent aviators, and particularly those who have won +the greatest amount of success. Wonderful as the results have been +few of the aviators are really satisfied. Their successes have merely +spurred them on to new endeavors, the ultimate end being the development +of an absolutely perfect aircraft. + +Among the men who have been thus experimenting are the Wright Brothers, +who last year (1909) brought out a craft totally different as regards +proportions and weight from the one used the preceding year. One marked +result was a gain of about 3 1/2 miles an hour in speed. + +Dimensions of 1908 Machine. + +The 1908 model aeroplane was 40 by 29 feet over all. The carrying +surfaces, that is, the two aerocurves, were 40 by 6 feet, having a +parabolical curve of one in twelve. With about 70 square feet of surface +in the rudders, the total surface given was about 550 square feet. +The engine, which is the invention of the Wright brothers, weighed, +approximately, 200 pounds, and gave about 25 horsepower at 1,400 +revolutions per minute. The total weight of the aeroplane, exclusive of +passenger, but inclusive of engine, was about 1,150 pounds. This result +showed a lift of a fraction over 2 1/4 pounds to the square foot of +carrying surface. The speed desired was 40 miles an hour, but the +machine was found to make only a scant 39 miles an hour. The upright +struts were about 7/8-inch thick, the skids, 2 1/2 by 1 1/4 inches +thick. + +Dimensions of 1909 Machine. + +The 1909 aeroplane was built primarily for greater speed, and relatively +heavier; to be less at the mercy of the wind. This result was obtained +as follows: The aerocurves, or carrying surfaces, were reduced in +dimensions from 40 by 6 feet to 36 by 5 1/2 feet, the curve remaining +the same, one in twelve. The upright struts were cut from seven-eighths +inch to five-eighths inch, and the skids from two and one-half by one +and one-quarter to two and one-quarter by one and three-eighths inches. +This result shows that there were some 81 square feet of carrying +surface missing over that of last year's model. and some 25 pounds loss +of weight. Relatively, though, the 1909 model aeroplane, while actually +25 pounds lighter, is really some 150 pounds heavier in the air than the +1908 model, owing to the lesser square feet of carrying surface. + +Some of the Results Obtained. + +Reducing the carrying surfaces from 6 to 5 1/2 feet gave two +results--first, less carrying capacity; and, second, less head-on +resistance, owing to the fact that the extent of the parabolic curve +in the carrying surfaces was shortened. The "head-on" resistance is +the retardance the aeroplane meets in passing through the air, and is +counted in square feet. In the 1908 model the curve being one in twelve +and 6 feet deep, gave 6 inches of head-on resistance. The plane being +40 feet spread, gave 6 inches by 40 feet, or 20 square feet of head-on +resistance. Increasing this figure by a like amount for each plane, and +adding approximately 10 square feet for struts, skids and wiring, we +have a total of approximately, 50 square feet of surface for "head-on" +resistance. + +In the 1909 aeroplane, shortening the curve 6 inches at the parabolic +end of the curve took off 1 inch of head-on resistance. Shortening the +spread of the planes took off between 3 and 4 square feet of head-on +resistance. Add to this the total of 7 square feet, less curve surface +and about 1 square foot, less wire and woodwork resistance, and we +have a grand total of, approximately, 12 square feet of less "head-on" +resistance over the 1908 model. + +Changes in Engine Action. + +The engine used in 1909 was the same one used in 1908, though some minor +changes were made as improvements; for instance, a make and break spark +was used, and a nine-tooth, instead of a ten-tooth magneto gear-wheel +was used. This increased the engine revolutions per minute from 1,200 to +1,400, and the propeller revolutions per minute from 350 to 371, giving +a propeller thrust of, approximately, 170 foot pounds instead of 153, as +was had last year. + +More Speed and Same Capacity. + +One unsatisfactory feature of the 1909 model over that of 1908, +apparently, was the lack of inherent lateral stability. This was caused +by the lesser surface and lesser extent of curvatures at the portions +of the aeroplane which were warped. This defect did not show so plainly +after Mr. Orville Wright had become fully proficient in the handling of +the new machine, and with skillful management, the 1909 model aeroplane +will be just as safe and secure as the other though it will take a +little more practice to get that same degree of skill. + +To sum up: The aeroplane used in 1909 was 25 pounds lighter, but really +about 150 pounds heavier in the air, had less head-on resistance, and +greater propeller thrust. The speed was increased from about 39 miles +per hour to 42 1/2 miles per hour. The lifting capacity remained about +the same, about 450 pounds capacity passenger-weight, with the 1908 +machine. In this respect, the loss of carrying surface was compensated +for by the increased speed. + +During the first few flights it was plainly demonstrated that it would +need the highest skill to properly handle the aeroplane, as first one +end and then the other would dip and strike the ground, and either tear +the canvas or slew the aeroplane around and break a skid. + +Wrights Adopt Wheeled Gears. + +In still another important respect the Wrights, so far as the output +of one of their companies goes, have made a radical change. All the +aeroplanes turned out by the Deutsch Wright Gesellschaft, according to +the German publication, _Automobil-Welt_, will hereafter be equipped +with wheeled running gears and tails. The plan of this new machine is +shown in the illustration on page 145. The wheels are three in number, +and are attached one to each of the two skids, just under the front edge +of the planes, and one forward of these, attached to a cross-member. It +is asserted that with these wheels the teaching of purchasers to operate +the machines is much simplified, as the beginners can make short flights +on their own account without using the starting derrick. + +This is a big concession for the Wrights to make, as they have hitherto +adhered stoutly to the skid gear. While it is true they do not control +the German company producing their aeroplanes, yet the nature of their +connection with the enterprise is such that it may be taken for granted +no radical changes in construction would be made without their approval +and consent. + +Only Three Dangerous Rivals. + +Official trials with the 1909 model smashed many records and leave the +Wright brothers with only three dangerous rivals in the field, and with +basic patents which cover the curve, warp and wing-tip devices found on +all the other makes of aeroplanes. These three rivals are the Curtiss +and Voisin biplane type and the Bleriot monoplane pattern. + +The Bleriot monoplane is probably the most dangerous rival, as this make +of machine has a record of 54 miles per hour, has crossed the English +channel, and has lifted two passengers besides the operator. The +latest type of this machine only weighs 771.61 pounds complete, without +passengers, and will lift a total passenger weight of 462.97 pounds, +which is a lift of 5.21 pounds to the square foot. This is a better +result than those published by the Wright brothers, the best noted being +4.25 pounds per square foot. + +Other Aviators at Work. + +The Wrights, however, are not alone in their efforts to promote the +efficiency of the flying machine. Other competent inventive aviators, +notably Curtiss, Voisin, Bleriot and Farman, are close after them. The +Wrights, as stated, have a marked advantage in the possession of +patents covering surface plane devices which have thus far been found +indispensable in flying machine construction. Numerous law suits growing +out of alleged infringements of these patents have been started, and +others are threatened. What effect these actions will have in deterring +aviators in general from proceeding with their experiments remains to be +seen. + +In the meantime the four men named--Curtiss, Voisin, Bleriot and +Farman--are going ahead regardless of consequences, and the inventive +genius of each is so strong that it is reasonable to expect some +remarkable developments in the near future. + +Smallest of Flying Machines. + +To Santos Dumont must be given the credit of producing the smallest +practical flying machine yet constructed. True, he has done nothing +remarkable with it in the line of speed, but he has demonstrated the +fact that a large supporting surface is not an essential feature. + +This machine is named "La Demoiselle." It is a monoplane of the dihedral +type, with a main plane on each side of the center. These main +planes are of 18 foot spread, and nearly 6 1/2 feet in depth, giving +approximately 115 feet of surface area. The total weight is 242 +pounds, which is 358 pounds less than any other machine which has been +successfully used. The total depth from front to rear is 26 feet. + +The framework is of bamboo, strengthened and held taut with wire guys. + +Have One Rule in Mind. + +In this struggle for mastery in flying machine efficiency all the +contestants keep one rule in mind, and this is: + +"The carrying capacity of an aeroplane is governed by the peripheral +curve of its carrying surfaces, plus the speed; and the speed +is governed by the thrust of the propellers, less the 'head-on' +resistance." + +Their ideas as to the proper means of approaching the proposition +may, and undoubtedly are, at variance, but the one rule in solving the +problem of obtaining the greatest carrying capacity combined with the +greatest speed, obtains in all instances. + + + +CHAPTER XVII. SOME OF THE NEW DESIGNS. + +Spurred on by the success attained by the more experienced and better +known aviators numerous inventors of lesser fame are almost daily +producing practical flying machines varying radically in construction +from those now in general use. + +One of these comparatively new designs is the Van Anden biplane, made +by Frank Van Anden of Islip, Long Island, a member of the New York +Aeronautic Society. While his machine is wholly experimental, many +successful short flights were made with it last fall (1909). One flight, +made October 19th, 1909, is of particular interest as showing the +practicability of an automatic stabilizing device installed by the +inventor. The machine was caught in a sudden severe gust of wind and +keeled over, but almost immediately righted itself, thus demonstrating +in a most satisfactory manner the value of one new attachment. + +Features of Van Anden Model. + +In size the surfaces of the main biplane are 26 feet in spread, and 4 +feet in depth from front to rear. The upper and lower planes are 4 feet +apart. Silkolene coated with varnish is used for the coverings. Ribs +(spruce) are curved one inch to the foot, the deepest part of the curve +(4 inches) being one foot back from the front edge of the horizontal +beam. Struts (also of spruce, as is all the framework) are elliptical in +shape. The main beams are in three sections, nearly half round in form, +and joined by metal sleeves. + +There is a two-surface horizontal rudder, 2x2x4 feet, in front. This +is pivoted at its lateral center 8 feet from the front edge of the main +planes. In the rear is another two-surface horizontal rudder 2x2x2 1/2 +feet, pivoted in the same manner as the front one, 15 feet from the rear +edges of the main planes. + +Hinged to the rear central strut of the rear rudder is a vertical rudder +2 feet high by 3 feet in length. + +The Method of Control. + +In the operation of these rudders--both front and rear--and the +elevation and depression of the main planes, the Curtiss system is +employed. Pushing the steering-wheel post outward depresses the front +edges of the planes, and brings the machine downward; pulling the +steering-wheel post inward elevates the front edges of the planes and +causes the machine to ascend. + +Turning the steering wheel itself to the right swings the tail rudder to +the left, and the machine, obeying this like a boat, turns in the same +direction as the wheel is turned. By like cause turning the wheel to the +left turns the machine to the left. + +Automatic Control of Wings. + +There are two wing tips, each of 6 feet spread (length) and 2 feet from +front to rear. These are hinged half way between the main surfaces to +the two outermost rear struts. Cables run from these to an automatic +device working with power from the engine, which automatically operates +the tips with the tilting of the machine. Normally the wing tips are +held horizontal by stiff springs introduced in the cables outside of the +device. + +It was the successful working of this device which righted the Van +Anden craft when it was overturned in the squall of October 19th, 1909. +Previous to that occurrence Mr. Van Anden had looked upon the device as +purely experimental, and had admitted that he had grave uncertainty as +to how it would operate in time of emergency. He is now quoted as being +thoroughly satisfied with its practicability. It is this automatic +device which gives the Van Anden machine at least one distinctively new +feature. + +While on this subject it will not be amiss to add that Mr. Curtiss does +not look kindly on automatic control. "I would rather trust to my own +action than that of a machine," he says. This is undoubtedly good +logic so far as Mr. Curtiss is concerned, but all aviators are not so +cool-headed and resourceful. + +Motive Power of Van Anden. + +A 50-horsepower "H-F" water cooled motor drives a laminated wood +propeller 6 feet in diameter, with a 17 degree pitch at the extremities, +increasing toward the hub. The rear end of the motor is about 6 inches +back from the rear transverse beam and the engine shaft is in a direct +line with the axes of the two horizontal rudders. An R. I. V. ball +bearing carries the shaft at this point. Flying, the motor turns at +about 800 revolutions per minute, delivering 180 pounds pull. A test of +the motor running at 1,200 showed a pull of 250 pounds on the scales. + +Still Another New Aeroplane. + +Another new aeroplane is that produced by A. M. Herring (an old-timer) +and W. S. Burgess, under the name of the Herring-Burgess. This is also +equipped with an automatic stability device for maintaining the balance +transversely. The curvature of the planes is also laid out on new +lines. That this new plan is effective is evidenced by the fact that the +machine has been elevated to an altitude of 40 feet by using one-half +the power of the 30-horsepower motor. + +The system of rudder and elevation control is very simple. The aviator +sits in front of the lower plane, and extending his arms, grasps two +supports which extend down diagonally in front. On the under side of +these supports just beneath his fingers are the controls which operate +the vertical rudder, in the rear. Thus, if he wishes to turn to the +right, he presses the control under the fingers of his right hand; if to +the left, that under the fingers of his left hand. The elevating rudder +is operated by the aviator's right foot, the control being placed on a +foot-rest. + +Motor Is Extremely Light. + +Not the least notable feature of the craft is its motor. Although +developing, under load, 30-horsepower, or that of an ordinary +automobile, it weighs, complete, hardly 100 pounds. Having occasion to +move it a little distance for inspection, Mr. Burgess picked it up and +walked off with it--cylinders, pistons, crankcase and all, even the +magneto, being attached. There are not many 30-horsepower engines which +can be so handled. Everything about it is reduced to its lowest terms +of simplicity, and hence, of weight. A single camshaft operates not +only all of the inlet and exhaust valves, but the magneto and gear water +pump, as well. The motor is placed directly behind the operator, and the +propeller is directly mounted on the crankshaft. + +This weight of less than 100 pounds, it must be remembered, is not for +the motor alone; it includes the entire power plant equipment. + +The "thrust" of the propeller is also extraordinary, being between 250 +and 260 pounds. The force of the wind displacement is strong enough to +knock down a good-sized boy as one youngster ascertained when he got +behind the propeller as it was being tested. He was not only knocked +down but driven for some distance away from the machine. The propeller +has four blades which are but little wider than a lath. + +Machine Built by Students. + +Students at the University of Pennsylvania, headed by Laurence J. Lesh, +a protege of Octave Chanute, have constructed a practical aeroplane of +ordinary maximum size, in which is incorporated many new ideas. The most +unique of these is to be found in the steering gear, and the provision +made for the accommodation of a pupil while taking lessons under an +experienced aviator. + +Immediately back of the aviator is an extra seat and an extra steering +wheel which works in tandem style with the front wheel. By this +arrangement a beginner may be easily and quickly taught to have +perfect control of the machine. These tandem wheels are also handy for +passengers who may wish to operate the car independently of one another, +it being understood, of course, that there will be no conflict of +action. + +Frame Size and Engine Power. + +The frame has 36 feet spread and measures 35 feet from the front edge to +the end of the tail in the rear. It is equipped with two rear propellers +operated by a Ramsey 8-cylinder motor of 50 horsepower, placed +horizontally across the lower plane, with the crank shaft running clear +through the engine. + +The "Pennsylvania I" is the first two-propeller biplane chainless +car, this scheme having been adopted in order to avoid the crossing of +chains. The lateral control is by a new invention by Octave Chanute +and Laurence J. Lesh, for which Lesh is now applying for a patent. The +device was worked out before the Wright brothers' suit was begun, and is +said to be superior to the Wright warping or the Curtiss ailerons. The +landing device is also new in design. This aeroplane will weigh about +1,500 pounds, and will carry fuel for a flight of 150 miles, and it is +expected to attain a speed of at least 45 miles an hour. + +There are others, lots of them, too numerous in fact to admit of mention +in a book of this size. + + + +CHAPTER XVIII. DEMAND FOR FLYING MACHINES. + +As a commercial proposition the manufacture and sale of motor-equipped +aeroplanes is making much more rapid advance than at first obtained in +the similar handling of the automobile. Great, and even phenomenal, +as was the commercial development of the motor car, that of the flying +machine is even greater. This is a startling statement, but it is fully +warranted by the facts. + +It is barely more than a year ago (1909) that attention was seriously +attracted to the motor-equipped aeroplane as a vehicle possible of +manipulation by others than professional aviators. Up to that time +such actual flights as were made were almost exclusively with the sole +purpose of demonstrating the practicability of the machine, and the +merits of the ideas as to shape, engine power, etc., of the various +producers. + +Results of Bleriot's Daring. + +It was not until Bleriot flew across the straits of Dover on July 25th, +1909, that the general public awoke to a full realization of the fact +that it was possible for others than professional aviators to indulge +in aviation. Bleriot's feat was accepted as proof that at last +an absolutely new means of sport, pleasure and research, had been +practically developed, and was within the reach of all who had the +inclination, nerve and financial means to adopt it. + +From this event may be dated the birth of the modern flying machine into +the world of business. The automobile was taken up by the general public +from the very start because it was a proposition comparatively easy of +demonstration. There was nothing mysterious or uncanny in the fact that +a wheeled vehicle could be propelled on solid, substantial roads by +means of engine power. And yet it took (comparatively speaking) a long +time to really popularize the motor car. + +Wonderful Results in a Year. + +Men of large financial means engaged in the manufacture of automobiles, +and expended fortunes in attracting public attention to them through the +medium of advertisements, speed and road contests, etc. By these means +a mammoth business has been built up, but bringing this business to its +present proportions required years of patient industry and indomitable +pluck. + +At this writing, less than a year from the day when Bleriot crossed the +channel, the actual sales of flying machines outnumber the actual sales +of automobiles in the first year of their commercial development. This +may appear incredible, but it is a fact as statistics will show. + +In this connection we should take into consideration the fact that up to +a year ago there was no serious intention of putting flying machines +on the market; no preparations had been made to produce them on a +commercial scale; no money had been expended in advertisements with a +view to selling them. + +Some of the Actual Results. + +Today flying machines are being produced on a commercial basis, and +there is a big demand for them. The people making them are overcrowded +with orders. Some of the producers are already making arrangements to +enlarge their plants and advertise their product for sale the same as +is being done with automobiles, while a number of flying machine motor +makers are already promoting the sale of their wares in this way. + +Here are a few actual figures of flying machine sales made by the more +prominent producers since July 25th, 1909. + +Santos Dumont, 90 machines; Bleriot, 200; Farman, 130; +Clemenceau-Wright, 80; Voisin, 100; Antoinette, 100. Many of these +orders have been filled by delivery of the machines, and in others the +construction work is under way. + +The foregoing are all of foreign make. In this country Curtiss and the +Wrights are engaged in similar work, but no actual figures of their +output are obtainable. + +Larger Plants Are Necessary. + +And this situation exists despite the fact that none of the producers +are really equipped with adequate plants for turning out their +machines on a modern, business-like basis. The demand was so sudden and +unexpected that it found them poorly prepared to meet it. This, however, +is now being remedied by the erection of special plants, the enlargement +of others, and the introduction of new machinery and other labor-saving +conveniences. + +Companies, with large capitalization, to engage in the exclusive +production of airships are being organized in many parts of the world. +One notable instance of this nature is worth quoting as illustrative +of the manner in which the production of flying machines is being +commercialized. This is the formation at Frankfort, Germany, of the +Flugmaschine Wright, G. m. b. H., with a capital of $119,000, the +Krupps, of Essen, being interested. + +Prices at Which Machines Sell. + +This wonderful demand from the public has come notwithstanding the fact +that the machines, owing to lack of facilities for wholesale production, +are far from being cheap. Such definite quotations as are made are on +the following basis: + +Santos Dumont--List price $1,000, but owing to the rush of orders agents +are readily getting from $1,300 to $1,500. This is the smallest machine +made. + +Bleriot--List price $2,500. This is for the cross-channel type, with +Anzani motor. + +Antoinette--List price from $4,000 to $5,000, according to size. + +Wright--List price $5,600. + +Curtiss--List price $5,000. + +There is, however, no stability in prices as purchasers are almost +invariably ready to pay a considerable premium to facilitate delivery. + +The motor is the most expensive part of the flying machine. Motor +prices range from $500 to $2,000, this latter amount being asked for the +Curtiss engine. + +Systematic Instruction of Amateurs. + +In addition to the production of flying machines many of the experienced +aviators are making a business of the instruction of amateurs. Curtiss +and the Wrights in this country have a number of pupils, as have also +the prominent foreigners. Schools of instruction are being opened in +various parts of the world, not alone as private money-making ventures, +but in connection with public educational institutions. One of these +latter is to be found at the University of Barcelona, Spain. + +The flying machine agent, the man who handles the machines on a +commission, has also become a known quantity, and will soon be as +numerous as his brother of the automobile. The sign "John Bird, agent +for Skimmer's Flying Machine," is no longer a curiosity. + +Yes, the Airship Is Here. + +From all of which we may well infer that the flying machine in practical +form has arrived, and that it is here to stay. It is no exaggeration to +say that the time is close at hand when people will keep flying machines +just as they now keep automobiles, and that pleasure jaunts will be +fully as numerous and popular. With the important item of practicability +fully demonstrated, "Come, take a trip in my airship," will have more +real significance than now attaches to the vapid warblings of the +vaudeville vocalist. + +As a further evidence that the airship is really here, and that its +presence is recognized in a business way, the action of life and +accident insurance companies is interesting. Some of them are +reconstructing their policies so as to include a special waiver of +insurance by aviators. Anything which compels these great corporations +to modify their policies cannot be looked upon as a mere curiosity or +toy. + +It is some consolation to know that the movement in this direction is +not thus far widespread. Moreover it is more than probable that the +competition for business will eventually induce the companies to act +more liberally toward aviators, especially as the art of aviation +advances. + + + +CHAPTER XIX. LAW OF THE AIRSHIP. + +Successful aviation has evoked some peculiar things in the way of legal +action and interpretation of the law. + +It is well understood that a man's property cannot be used without his +consent. This is an old established principle in common law which holds +good today. + +The limits of a man's property lines, however, have not been so well +understood by laymen. According to eminent legal authorities such as +Blackstone, Littleton and Coke, the "fathers of the law," the owner of +realty also holds title above and below the surface, and this theory is +generally accepted without question by the courts. + +Rights of Property Owners. + +In other words the owner of realty also owns the sky above it without +limit as to distance. He can dig as deep into his land, or go as high +into the air as he desires, provided he does not trespass upon or injure +similar rights of others. + +The owner of realty may resist by force, all other means having failed, +any trespass upon, or invasion of his property. Other people, for +instance, may not enter upon it, or over or under it, without his +express permission and consent. There is only one exception, and this is +in the case of public utility corporations such as railways which, +under the law of eminent domain, may condemn a right of way across the +property of an obstinate owner who declines to accept a fair price for +the privilege. + +Privilege Sharply Confined. + +The law of eminent domain may be taken advantage of only by corporations +which are engaged in serving the public. It is based upon the principle +that the advancement and improvement of a community is of more +importance and carries with it more rights than the interests of the +individual owner. But even in cases where the right of eminent domain is +exercised there can be no confiscation of the individual's property. + +Exercising the right of eminent domain is merely obtaining by public +purchase what is held to be essential to the public good, and which +cannot be secured by private purchase. When eminent domain proceedings +are resorted to the court appoints appraisers who determine upon the +value of the property wanted, and this value (in money) is paid to the +owner. + +How It Affects Aviation. + +It should be kept in mind that this privilege of the "right of eminent +domain" is accorded only to corporations which are engaged in serving +the public. Individuals cannot take advantage of it. Thus far all +aviation has been conducted by individuals; there are no flying machine +or airship corporations regularly engaged in the transportation of +passengers, mails or freight. + +This leads up to the question "What would happen if realty owners +generally, or in any considerable numbers, should prohibit the +navigation of the air above their holdings?" It is idle to say such +a possibility is ridiculous--it is already an actuality in a few +individual instances. + +One property owner in New Jersey, a justice of the peace, maintains a +large sign on the roof of his house warning aviators that they must not +trespass upon his domain. That he is acting well within his rights in +doing this is conceded by legal authorities. + +Hard to Catch Offenders. + +But, suppose the alleged trespass is committed, what is the property +owner going to do about it? He must first catch the trespasser and this +would be a pretty hard job. He certainly could not overtake him, unless +he kept a racing aeroplane for this special purpose. It would be +equally difficult to identify the offender after the offense had been +committed, even if he were located, as aeroplanes carry no license +numbers. + +Allowing that the offender should be caught the only recourse of the +realty owner is an action for damages. He may prevent the commission of +the offense by force if necessary, but after it is committed he can only +sue for damages. And in doing this he would have a lot of trouble. + +Points to Be Proven. + +One of the first things the plaintiff would be called upon to prove +would be the elevation of the machine. If it were reasonably close to +the ground there would, of course, be grave risk of damage to fences, +shrubbery, and other property, and the court would be justified in +holding it to be a nuisance that should be suppressed. + +If, on the other hand; the machine was well up in the air, but going +slowly, or hovering over the plaintiff's property, the court might be +inclined to rule that it could not possibly be a nuisance, but right +here the court would be in serious embarrassment. By deciding that it +was not a nuisance he would virtually override the law against invasion +of a man's property without his consent regardless of the nature of the +invasion. By the same decision he would also say in effect that, if one +flying machine could do this a dozen or more would have equal right to +do the same thing. While one machine hovering over a certain piece of +property may be no actual nuisance a dozen or more in the same position +could hardly be excused. + +Difficult to Fix Damages. + +Such a condition would tend to greatly increase the risk of accident, +either through collision, or by the carelessness of the aviators in +dropping articles which might cause damages to the people or property +below. In such a case it would undoubtedly be a nuisance, and in +addition to a fine, the offender would also be liable for the damages. + +Taking it for granted that no actual damage is done, and the owner +merely sues on account of the invasion of his property, how is the +amount of compensation to be fixed upon? The owner has lost nothing; no +part of his possessions has been taken away; nothing has been injured +or destroyed; everything is left in exactly the same condition as before +the invasion. And yet, if the law is strictly interpreted, the offender +is liable. + +Right of Way for Airships. + +Somebody has suggested the organization of flying-machine corporations +as common carriers, which would give them the right of eminent domain +with power to condemn a right of way. But what would they condemn? There +is nothing tangible in the air. Railways in condemning a right of way +specify tangible property (realty) within certain limits. How would an +aviator designate any particular right of way through the air a certain +number of feet in width, and a certain distance from the ground? + +And yet, should the higher courts hold to the letter of the law and +decide that aviators have no right to navigate their craft over private +property, something will have to be done to get them out of the dilemma, +as aviation is too far advanced to be discarded. Fortunately there is +little prospect of any widespread antagonism among property owners so +long as aviators refrain from making nuisances of themselves. + +Possible Solution Offered. + +One possible solution is offered and that is to confine the path of +airships to the public highways so that nobody's property rights would +be invaded. In addition, as a matter of promoting safety for both +operators and those who may happen to be beneath the airships as they +pass over a course, adoption of the French rules are suggested. These +are as follows: + +Aeroplanes, when passing, must keep to the right, and pass at a distance +of at least 150 feet. They are free from this rule when flying at +altitudes of more than 100 feet. Every machine when flying at night or +during foggy weather must carry a green light on the right, and a red +light on the left, and a white headlight on the front. + +These are sensible rules, but may be improved upon by the addition of a +signal system of some kind, either horn, whistle or bell. + +Responsibility of Aviators. + +Mr. Jay Carver Bossard, in recent numbers of _Fly_, brings out some +curious and interesting legal points in connection with aviation, among +which are the following: + +"Private parties who possess aerial craft, and desire to operate the +same in aerial territory other than their own, must obtain from land +owners special permission to do so, such permission to be granted only +by agreement, founded upon a valid consideration. Otherwise, passing +over another's land will in each instance amount to a trespass. + +"Leaving this highly technical side of the question, let us turn to +another view: the criminal and tort liability of owners and operators to +airship passengers. If A invites B to make an ascension with him in his +machine, and B, knowing that A is merely an enthusiastic amateur and +far from being an expert, accepts and is through A's innocent negligence +injured, he has no grounds for recovery. But if A contracts with B, to +transport him from one place to another, for a consideration, and B is +injured by the poor piloting of A, A would be liable to B for damages +which would result. Now in order to safeguard such people as B, curious +to the point of recklessness, the law will have to require all airship +operators to have a license, and to secure this license airship pilots +will have to meet certain requirements. Here again is a question. Who +is going to say whether an applicant is competent to pilot a balloon or +airship? + +Fine for an Aeronaut. + +"An aeroplane while maneuvering is suddenly caught by a treacherous gale +and swept to the ground. A crowd of people hasten over to see if the +aeronaut is injured, and in doing so trample over Tax-payer Smith's +garden, much to the detriment of his growing vegetables and flowers. Who +is liable for the damages? Queer as it may seem, a case very similar to +this was decided in 1823, in the New York supreme court, and it was held +that the aeronaut was liable upon the following grounds: 'To render one +man liable in trespass for the acts of others, it must appear either +that they acted in concert, or that the act of the one, ordinarily and +naturally produced the acts of the others, Ascending in a balloon is not +an unlawful act, but it is certain that the aeronaut has no control +over its motion horizontally, but is at the sport of the wind, and is +to descend when and how he can. His reaching the earth is a matter of +hazard. If his descent would according to the circumstances draw a crowd +of people around him, either out of curiosity, or for the purpose +of rescuing him from a perilous situation, all this he ought to have +foreseen, and must be responsible for.' + +Air Not Really Free. + +"The general belief among people is, that the air is free. Not only free +to breathe and enjoy, but free to travel in, and that no one has any +definite jurisdiction over, or in any part of it. Now suppose this were +made a legal doctrine. Would a murder perpetrated above the clouds have +to go unpunished? Undoubtedly. For felonies committed upon the high seas +ample provision is made for their punishment, but new provisions will +have to be made for crimes committed in the air. + +Relations of Owner and Employee. + +"It is a general rule of law that a master is bound to provide +reasonably safe tools, appliances and machines for his servant. How this +rule is going to be applied in cases of aeroplanes, remains to be seen. +The aeroplane owner who hires a professional aeronaut, that is, one who +has qualified as an expert, owes him very little legal duty to supply +him with a perfect aeroplane. The expert is supposed to know as much +regarding the machine as the owner, if not more, and his acceptance of +his position relieves the owner from liability. When the owner hires an +amateur aeronaut to run the aeroplane, and teaches him how to manipulate +it, even though the prescribed manner of manipulation will make flight +safe, nevertheless if the machine is visibly defective, or known to be +so, any injury which results to the aeronaut the owner is liable for. + +As to Aeroplane Contracts. + +"At the present time there are many orders being placed with aeroplane +manufacturing companies. There are some unique questions to be raised +here under the law of contract. It is an elementary principle of law +that no one can be compelled to complete a contract which in itself is +impossible to perform. For instance, a contract to row a boat across +the Atlantic in two weeks, for a consideration, could never be enforced +because it is within judicial knowledge that such an undertaking is +beyond human power. Again, contracts formed for the doing of acts +contrary to nature are never enforcible, and here is where our +difficulty comes in. Is it possible to build a machine or species of +craft which will transport a person or goods through the air? The courts +know that balloons are practical; that is, they know that a bag +filled with gas has a lifting power and can move through the air at an +appreciable height. Therefore, a contract to transport a person in such +manner is a good contract, and the conditions being favorable could +undoubtedly be enforced. But the passengers' right of action for injury +would be very limited. + +No Redress for Purchasers. + +"In the case of giving warranties on aeroplanes, we have yet to see just +what a court is going to say. It is easy enough for a manufacturer to +guarantee to build a machine of certain dimensions and according to +certain specifications, but when he inserts a clause in the contract to +the effect that the machine will raise itself from the surface of the +earth, defy the laws of gravity, and soar in the heavens at the will of +the aviator, he is to say the least contracting to perform a miracle. + +"Until aeroplanes have been made and accepted as practical, no court +will force a manufacturer to turn out a machine guaranteed to fly. So +purchasers can well remember that if their machines refuse to fly they +have no redress against the maker, for he can always say, 'The industry +is still in its experimental stage.' In contracting for an engine no +builder will guarantee that the particular engine will successfully +operate the aeroplane. In fact he could never be forced to live up to +such an agreement, should he agree to a stipulation of that sort. The +best any engine maker will guarantee is to build an engine according to +specifications." + + + +CHAPTER XX. SOARING FLIGHT. + +By Octave Chanute. + +[5] There is a wonderful performance daily exhibited in southern climes +and occasionally seen in northerly latitudes in summer, which has +never been thoroughly explained. It is the soaring or sailing flight +of certain varieties of large birds who transport themselves on rigid, +unflapping wings in any desired direction; who in winds of 6 to 20 +miles per hour, circle, rise, advance, return and remain aloft for hours +without a beat of wing, save for getting under way or convenience in +various maneuvers. They appear to obtain from the wind alone all the +necessary energy, even to advancing dead against that wind. This feat is +so much opposed to our general ideas of physics that those who have +not seen it sometimes deny its actuality, and those who have only +occasionally witnessed it subsequently doubt the evidence of their own +eyes. Others, who have seen the exceptional performances, speculate on +various explanations, but the majority give it up as a sort of "negative +gravity." + +Soaring Power of Birds. + +The writer of this paper published in the "Aeronautical Annual" for 1896 +and 1897 an article upon the sailing flight of birds, in which he gave +a list of the authors who had described such flight or had advanced +theories for its explanation, and he passed these in review. He also +described his own observations and submitted some computations to +account for the observed facts. These computations were correct as +far as they went, but they were scanty. It was, for instance, shown +convincingly by analysis that a gull weighing 2.188 pounds, with a total +supporting surface of 2.015 square feet, a maximum body cross-section +of 0.126 square feet and a maximum cross-section of wing edges of 0.098 +square feet, patrolling on rigid wings (soaring) on the weather side of +a steamer and maintaining an upward angle or attitude of 5 degrees to 7 +degrees above the horizon, in a wind blowing 12.78 miles an hour, which +was deflected upward 10 degrees to 20 degrees by the side of the steamer +(these all being carefully observed facts), was perfectly sustained at +its own "relative speed" of 17.88 miles per hour and extracted from +the upward trend of the wind sufficient energy to overcome all the +resistances, this energy amounting to 6.44 foot-pounds per second. + +Great Power of Gulls. + +It was shown that the same bird in flapping flight in calm air, with an +attitude or incidence of 3 degrees to 5 degrees above the horizon and +a speed of 20.4 miles an hour was well sustained and expended 5.88 +foot-pounds per second, this being at the rate of 204 pounds sustained +per horsepower. It was stated also that a gull in its observed +maneuvers, rising up from a pile head on unflapping wings, then plunging +forward against the wind and subsequently rising higher than his +starting point, must either time his ascents and descents exactly with +the variations in wind velocities, or must meet a wind billow rotating +on a horizontal axis and come to a poise on its crest, thus availing of +an ascending trend. + +But the observations failed to demonstrate that the variations of the +wind gusts and the movements of the bird were absolutely synchronous, +and it was conjectured that the peculiar shape of the soaring wing of +certain birds, as differentiated from the flapping wing, might, when +experimented upon, hereafter account for the performance. + +Mystery to be Explained. + +These computations, however satisfactory they were for the speed of +winds observed, failed to account for the observed spiral soaring of +buzzards in very light winds and the writer was compelled to confess: +"Now, this spiral soaring in steady breezes of 5 to 10 miles per hour +which are apparently horizontal, and through which the bird maintains an +average speed of about 20 miles an hour, is the mystery to be explained. +It is not accounted for, quantitatively, by any of the theories which +have been advanced, and it is the one performance which has led some +observers to claim that it was done through 'aspiration.' i, e., that +a bird acted upon by a current, actually drew forward into that current +against its exact direction of motion." + +Buzzards Soar in Dead Calm. + +A still greater mystery was propounded by the few observers who asserted +that they had seen buzzards soaring in a dead calm, maintaining their +elevation and their speed. Among these observers was Mr. E. C. Huffaker, +at one time assistant experimenter for Professor Langley. The writer +believed and said then that he must in some way have been mistaken, yet, +to satisfy himself, he paid several visits to Mr. Huffaker, in Eastern +Tennessee and took along his anemometer. He saw quite a number of +buzzards sailing at a height of 75 to 100 feet in breezes measuring 5 +or 6 miles an hour at the surface of the ground, and once he saw one +buzzard soaring apparently in a dead calm. + +The writer was fairly baffled. The bird was not simply gliding, +utilizing gravity or acquired momentum, he was actually circling +horizontally in defiance of physics and mathematics. It took two years +and a whole series of further observations to bring those two sciences +into accord with the facts. + +Results of Close Observations. + +Curiously enough the key to the performance of circling in a light wind +or a dead calm was not found through the usual way of gathering human +knowledge, i. e., through observations and experiment. These had failed +because I did not know what to look for. The mystery was, in fact, +solved by an eclectic process of conjecture and computation, but once +these computations indicated what observations should be made, the +results gave at once the reasons for the circling of the birds, for +their then observed attitude, and for the necessity of an independent +initial sustaining speed before soaring began. Both Mr. Huffaker and +myself verified the data many times and I made the computations. + +These observations disclosed several facts: + +1st.--That winds blowing five to seventeen miles per hour frequently had +rising trends of 10 degrees to 15 degrees, and that upon occasions when +there seemed to be absolutely no wind, there was often nevertheless a +local rising of the air estimated at a rate of four to eight miles or +more per hour. This was ascertained by watching thistledown, and rising +fogs alongside of trees or hills of known height. Everyone will readily +realize that when walking at the rate of four to eight miles an hour in +a dead calm the "relative wind" is quite inappreciable to the senses and +that such a rising air would not be noticed. + +2nd.--That the buzzard, sailing in an apparently dead horizontal calm, +progressed at speeds of fifteen to eighteen miles per hour, as measured +by his shadow on the ground. It was thought that the air was then +possibly rising 8.8 feet per second, or six miles per hour. + +3rd.--That when soaring in very light winds the angle of incidence of +the buzzards was negative to the horizon--i. e., that when seen coming +toward the eye, the afternoon light shone on the back instead of on the +breast, as would have been the case had the angle been inclined above +the horizon. + +4th.--That the sailing performance only occurred after the bird had +acquired an initial velocity of at least fifteen or eighteen miles per +hour, either by industrious flapping or by descending from a perch. + +An Interesting Experiment. + +5th.--That the whole resistance of a stuffed buzzard, at a negative +angle of 3 degrees in a current of air of 15.52 miles per hour, was 0.27 +pounds. This test was kindly made for the writer by Professor A. F. Zahm +in the "wind tunnel" of the Catholic University at Washington, D. C., +who, moreover, stated that the resistance of a live bird might be less, +as the dried plumage could not be made to lie smooth. + +This particular buzzard weighed in life 4.25 pounds, the area of his +wings and body was 4.57 square feet, the maximum cross-section of +his body was 0.110 square feet, and that of his wing edges when fully +extended was 0.244 square feet. + +With these data, it became surprisingly easy to compute the performance +with the coefficients of Lilienthal for various angles of incidence +and to demonstrate how this buzzard could soar horizontally in a dead +horizontal calm, provided that it was not a vertical calm, and that the +air was rising at the rate of four or six miles per hour, the lowest +observed, and quite inappreciable without actual measuring. + +Some Data on Bird Power. + +The most difficult case is purposely selected. For if we assume that the +bird has previously acquired an initial minimum speed of seventeen miles +an hour (24.93 feet per second, nearly the lowest measured), and that +the air was rising vertically six miles an hour (8.80 feet per second), +then we have as the trend of the "relative wind" encountered: + + 6 + -- = 0.353, or the tangent of 19 degrees 26'. + 17 + +which brings the case into the category of rising wind effects. But the +bird was observed to have a negative angle to the horizon of about 3 +degrees, as near as could be guessed, so that his angle of incidence to +the "relative wind" was reduced to 16 degrees 26'. + +The relative speed of his soaring was therefore: + +Velocity = square root of (17 squared + 6 squared) = 18.03 miles per +hour. + +At this speed, using the Langley co-efficient recently practically +confirmed by the accurate experiments of Mr. Eiffel, the air pressure +would be: + +18.03 squared X 0.00327 = 1.063 pounds per square foot. + +If we apply Lilienthal's co-efficients for an angle of 6 degrees 26', we +have for the force in action: + + Normal: 4.57 X 1.063 X 0.912 = 4.42 pounds. + + Tangential: 4.57 X 1.063 X 0.074 = - 0.359 pounds, + which latter, being negative, is a propelling force. + +Results Astonish Scientists. + +Thus we have a bird weighing 4.25 pounds not only thoroughly supported, +but impelled forward by a force of 0.359 pounds, at seventeen miles +per hour, while the experiments of Professor A. F. Zahm showed that the +resistance at 15.52 miles per hour was only 0.27 pounds, + + 17 squared + or 0.27 X ------- = 0.324 pounds, at seventeen miles an + 15.52 squared + hour. + +These are astonishing results from the data obtained, and they lead to +the inquiry whether the energy of the rising air is sufficient to make +up the losses which occur by reason of the resistance and friction of +the bird's body and wings, which, being rounded, do not encounter air +pressures in proportion to their maximum cross-section. + +We have no accurate data upon the co-efficients to apply and estimates +made by myself proved to be much smaller than the 0.27 pounds resistance +measured by Professor Zahm, so that we will figure with the latter as +modified. As the speed is seventeen miles per hour, or 24.93 feet per +second, we have for the work: + +Work done, 0.324 X 24.93 = 8.07 foot pounds per second. + +Endorsed by Prof. Marvin. + +Corresponding energy of rising air is not sufficient at four miles per +hour. This amounts to but 2.10 foot pounds per second, but if we assume +that the air was rising at the rate of seven miles per hour (10.26 feet +per second), at which the pressure with the Langley coefficient would be +0.16 pounds per square foot, we have on 4.57 square feet for energy of +rising air: 4.57 X 0.16 X 10.26 = 7.50 foot pounds per second, which +is seen to be still a little too small, but well within the limits of +error, in view of the hollow shape of the bird's wings, which receive +greater pressure than the flat planes experimented upon by Langley. + +These computations were chiefly made in January, 1899, and were +communicated to a few friends, who found no fallacy in them, but thought +that few aviators would understand them if published. They were then +submitted to Professor C. F. Marvin of the Weather Bureau, who is well +known as a skillful physicist and mathematician. He wrote that they +were, theoretically, entirely sound and quantitatively, probably, as +accurate as the present state of the measurements of wind pressures +permitted. The writer determined, however, to withhold publication until +the feat of soaring flight had been performed by man, partly because he +believed that, to ensure safety, it would be necessary that the machine +should be equipped with a motor in order to supplement any deficiency in +wind force. + +Conditions Unfavorable for Wrights. + +The feat would have been attempted in 1902 by Wright brothers if the +local circumstances had been more favorable. They were experimenting on +"Kill Devil Hill," near Kitty Hawk, N. C. This sand hill, about 100 +feet high, is bordered by a smooth beach on the side whence come the +sea breezes, but has marshy ground at the back. Wright brothers were +apprehensive that if they rose on the ascending current of air at the +front and began to circle like the birds, they might be carried by the +descending current past the back of the hill and land in the marsh. +Their gliding machine offered no greater head resistance in proportion +than the buzzard, and their gliding angles of descent are practically as +favorable, but the birds performed higher up in the air than they. + +Langley's Idea of Aviation. + +Professor Langley said in concluding his paper upon "The Internal Work +of the Wind": + +"The final application of these principles to the art of aerodromics +seems, then, to be, that while it is not likely that the perfected +aerodrome will ever be able to dispense altogether with the ability +to rely at intervals on some internal source of power, it will not be +indispensable that this aerodrome of the future shall, in order to go +any distance--even to circumnavigate the globe without alighting--need +to carry a weight of fuel which would enable it to perform this journey +under conditions analogous to those of a steamship, but that the fuel +and weight need only be such as to enable it to take care of itself in +exceptional moments of calm." + +Now that dynamic flying machines have been evolved and are being brought +under control, it seems to be worth while to make these computations and +the succeeding explanations known, so that some bold man will attempt +the feat of soaring like a bird. The theory underlying the performance +in a rising wind is not new, it has been suggested by Penaud and others, +but it has attracted little attention because the exact data and +the maneuvers required were not known and the feat had not yet been +performed by a man. The puzzle has always been to account for the +observed act in very light winds, and it is hoped that by the present +selection of the most difficult case to explain--i. e., the soaring in a +dead horizontal calm--somebody will attempt the exploit. + +Requisites for Soaring Flights. + +The following are deemed to be the requisites and maneuvers to master +the secrets of soaring flight: + +1st--Develop a dynamic flying machine weighing about one pound per +square foot of area, with stable equilibrium and under perfect control, +capable of gliding by gravity at angles of one in ten (5 3/4 degrees) in +still air. + +2nd.--Select locations where soaring birds abound and occasions where +rising trends of gentle winds are frequent and to be relied on. + +3rd.--Obtain an initial velocity of at least 25 feet per second before +attempting to soar. + +4th.--So locate the center of gravity that the apparatus shall assume a +negative angle, fore and aft, of about 3 degrees. + +Calculations show, however, that sufficient propelling force may still +exist at 0 degrees, but disappears entirely at +4 degrees. + +5th.--Circle like the bird. Simultaneously with the steering, incline +the apparatus to the side toward which it is desired to turn, so that +the centrifugal force shall be balanced by the centripetal force. The +amount of the required inclination depends upon the speed and on the +radius of the circle swept over. + +6th.--Rise spirally like the bird. Steer with the horizontal rudder, so +as to descend slightly when going with the wind and to ascend when going +against the wind. The bird circles over one spot because the rising +trends of wind are generally confined to small areas or local chimneys, +as pointed out by Sir H. Maxim and others. + +7th.--Once altitude is gained, progress may be made in any direction by +gliding downward by gravity. + +The bird's flying apparatus and skill are as yet infinitely superior +to those of man, but there are indications that within a few years the +latter may evolve more accurately proportioned apparatus and obtain +absolute control over it. + +It is hoped, therefore, that if there be found no radical error in the +above computations, they will carry the conviction that soaring flight +is not inaccessible to man, as it promises great economies of motive +power in favorable localities of rising winds. + +The writer will be grateful to experts who may point out any mistake +committed in data or calculations, and will furnish additional +information to any aviator who may wish to attempt the feat of soaring. + + + +CHAPTER XXI. FLYING MACHINES VS. BALLOONS. + +While wonderful success has attended the development of the dirigible +(steerable) balloon the most ardent advocates of this form of aerial +navigation admit that it has serious drawbacks. Some of these may be +described as follows: + +Expense and Other Items. + +Great Initial Expense.--The modern dirigible balloon costs a fortune. +The Zeppelin, for instance, costs more than $100,000 (these are official +figures). + +Expense of Inflation.--Gas evaporates rapidly, and a balloon must +be re-inflated, or partially re-inflated, every time it is used. The +Zeppelin holds 460,000 cubic feet of gas which, even at $1 per thousand, +would cost $460. + +Difficulty of Obtaining Gas.--If a balloon suddenly becomes deflated, by +accident or atmospheric conditions, far from a source of gas supply, it +is practically worthless. Gas must be piped to it, or the balloon carted +to the gas house--an expensive proceeding in either event. + +Lack of Speed and Control. + +Lack of Speed.--Under the most favorable conditions the maximum speed +of a balloon is 30 miles an hour. Its great bulk makes the high speed +attained by flying machines impossible. + +Difficulty of Control.--While the modern dirigible balloon is readily +handled in calm or light winds, its bulk makes it difficult to control +in heavy winds. + +The Element of Danger.--Numerous balloons have been destroyed by +lightning and similar causes. One of the largest of the Zeppelins was +thus lost at Stuttgart in 1908. + +Some Balloon Performances. + +It is only a matter of fairness to state that, under favorable +conditions, some very creditable records have been made with modern +balloons, viz: + +November 23d, 1907, the French dirigible Patrie, travelled 187 miles in +6 hours and 45 minutes against a light wind. This was a little over 28 +miles an hour. + +The Clement-Bayard, another French machine, sold to the Russian +government, made a trip of 125 miles at a rate of 27 miles an hour. + +Zeppelin No. 3, carrying eight passengers, and having a total lifting +capacity of 5,500 pounds of ballast in addition to passengers, weight +of equipment, etc., was tested in October, 1906, and made 67 miles in 2 +hours and 17 minutes, about 30 miles an hour. + +These are the best balloon trips on record, and show forcefully the +limitations of speed, the greatest being not over 30 miles an hour. + +Speed of Flying Machines. + +Opposed to the balloon performances we have flying machine trips (of +authentic records) as follows: + +Bleriot--monoplane--in 1908--52 miles an hour. + +Delagrange--June 22, 1908--10 1/2 miles in 16 minutes, approximately 42 +miles an hour. + +Wrights--October, 1905--the machine was then in its infancy--24 miles +in 38 minutes, approximately 44 miles an hour. On December 31, 1908, the +Wrights made 77 miles in 2 hours and 20 minutes. + +Lambert, a pupil of the Wrights, and using a Wright biplane, on October +18, 1909, covered 29.82 miles in 49 minutes and 39 seconds, being at +the rate of 36 miles an hour. This flight was made at a height of 1,312 +feet. + +Latham--October 21, 1909--made a short flight, about 11 minutes, in +the teeth of a 40 mile gale, at Blackpool, Eng. He used an Antoniette +monoplane, and the official report says: "This exhibition of nerve, +daring and ability is unparalled in the history of aviation." + +Farman--October 20, 1909--was in the air for 1 hour, 32 min., 16 +seconds, travelling 47 miles, 1,184 yards, a duration record for +England. + +Paulhan--January 18, 1901--47 1/2 miles at the rate of 45 miles an hour, +maintaining an altitude of from 1,000 to 2,000 feet. + +Expense of Producing Gas. + +Gas is indispensable in the operation of dirigible balloons, and gas +is expensive. Besides this it is not always possible to obtain it in +sufficient quantities even in large cities, as the supply on hand is +generally needed for regular customers. Such as can be had is either +water or coal gas, neither of which is as efficient in lifting power as +hydrogen. + +Hydrogen is the lightest and consequently the most buoyant of all known +gases. It is secured commercially by treating zinc or iron with dilute +sulphuric or hydrochloric acid. The average cost may be safely placed +at $10 per 1,000 feet so that, to inflate a balloon of the size of the +Zeppelin, holding 460,000 cubic feet, would cost $4,600. + +Proportions of Materials Required. + +In making hydrogen gas it is customary to allow 20 per cent for loss +between the generation and the introduction of the gas into the balloon. +Thus, while the formula calls for iron 28 times heavier than the weight +of the hydrogen required, and acid 49 times heavier, the real quantities +are 20 per cent greater. Hydrogen weighs about 0.09 ounce to the cubic +foot. Consequently if we need say 450,000 cubic feet of gas we must have +2,531.25 pounds in weight. To produce this, allowing for the 20 percent +loss, we must have 35 times its weight in iron, or over 44 tons. Of acid +it would take 60 times the weight of the gas, or nearly 76 tons. + +In Time of Emergency. + +These figures are appalling, and under ordinary conditions would be +prohibitive, but there are times when the balloon operator, unable to +obtain water or coal gas, must foot the bills. In military maneuvers, +where the field of operation is fixed, it is possible to furnish +supplies of hydrogen gas in portable cylinders, but on long trips +where sudden leakage or other cause makes descent in an unexpected spot +unavoidable, it becomes a question of making your own hydrogen gas or +deserting the balloon. And when this occurs the balloonist is up against +another serious proposition--can he find the necessary zinc or iron? Can +he get the acid? + +Balloons for Commercial Use. + +Despite all this the balloon has its uses. If there is to be such a +thing as aerial navigation in a commercial way--the carrying of freight +and passengers--it will come through the employment of such monster +balloons as Count Zeppelin is building. But even then the carrying +capacity must of necessity be limited. The latest Zeppelin creation, +a monster in size, is 450 feet long, and 42 1/2 feet in diameter. The +dimensions are such as to make all other balloons look like pigmies; +even many ocean-going steamers are much smaller, and yet its passenger +capacity is very small. On its 36-hour flight in May, 1909, the +Zeppelin, carried only eight passengers. The speed, however, was quite +respectable, 850 miles being covered in the 36 hours, a trifle over 23 +miles an hour. The reserve buoyancy, that is the total lifting capacity +aside from the weight of the airship and its equipment, is estimated at +three tons. + + + +CHAPTER XXII. PROBLEMS OF AERIAL FLIGHT. + +In a lecture before the Royal Society of Arts, reported in Engineering, +F. W. Lanchester took the position that practical flight was not the +abstract question which some apparently considered it to be, but a +problem in locomotive engineering. The flying machine was a locomotive +appliance, designed not merely to lift a weight, but to transport it +elsewhere, a fact which should be sufficiently obvious. Nevertheless one +of the leading scientific men of the day advocated a type in which +this, the main function of the flying machine, was overlooked. When +the machine was considered as a method of transport, the vertical screw +type, or helicopter, became at once ridiculous. It had, nevertheless, +many advocates who had some vague and ill-defined notion of subsequent +motion through the air after the weight was raised. + +Helicopter Type Useless. + +When efficiency of transport was demanded, the helicopter type was +entirely out of court. Almost all of its advocates neglected the effect +of the motion of the machine through the air on the efficiency of the +vertical screws. They either assumed that the motion was so slow as not +to matter, or that a patch of still air accompanied the machine in its +flight. Only one form of this type had any possibility of success. In +this there were two screws running on inclined axles--one on each +side of the weight to be lifted. The action of such inclined screw was +curious, and in a previous lecture he had pointed out that it was almost +exactly the same as that of a bird's wing. In high-speed racing craft +such inclined screws were of necessity often used, but it was at +a sacrifice of their efficiency. In any case the efficiency of the +inclined-screw helicopter could not compare with that of an aeroplane, +and that type might be dismissed from consideration so soon as +efficiency became the ruling factor of the design. + +Must Compete With Locomotive. + +To justify itself the aeroplane must compete, in some regard or other, +with other locomotive appliances, performing one or more of the purposes +of locomotion more efficiently than existing systems. It would be no use +unless able to stem air currents, so that its velocity must be greater +than that of the worst winds liable to be encountered. To illustrate the +limitations imposed on the motion of an aeroplane by wind velocity, Mr. +Lanchester gave the diagrams shown in Figs. 1 to 4. The circle in each +case was, he said, described with a radius equal to the speed of the +aeroplane in still air, from a center placed "down-wind" from the +aeroplane by an amount equal to the velocity of the wind. + +Fig. 1 therefore represented the case in which the air was still, and +in this case the aeroplane represented by _A_ had perfect liberty of +movement in any direction + +In Fig. 2 the velocity of the wind was half that of the aeroplane, and +the latter could still navigate in any direction, but its speed against +the wind was only one-third of its speed with the wind. + +In Fig. 3 the velocity of the wind was equal to that of the aeroplane, +and then motion against the wind was impossible; but it could move to +any point of the circle, but not to any point lying to the left of the +tangent _A_ _B_. Finally, when the wind had a greater speed than the +aeroplane, as in Fig. 4, the machine could move only in directions +limited by the tangents _A_ _C_ and _A_ _D_. + +Matter of Fuel Consumption. + +Taking the case in which the wind had a speed equal to half that of the +aeroplane, Mr. Lanchester said that for a given journey out and home, +down wind and back, the aeroplane would require 30 per cent more fuel +than if the trip were made in still air; while if the journey was made +at right angles to the direction of the wind the fuel needed would be 15 +per cent more than in a calm. This 30 per cent extra was quite a heavy +enough addition to the fuel; and to secure even this figure it was +necessary that the aeroplane should have a speed of twice that of the +maximum wind in which it was desired to operate the machine. Again, as +stated in the last lecture, to insure the automatic stability of the +machine it was necessary that the aeroplane speed should be largely in +excess of that of the gusts of wind liable to be encountered. + +Eccentricities of the Wind. + +There was, Mr. Lanchester said, a loose connection between the average +velocity of the wind and the maximum speed of the gusts. When the +average speed of the wind was 40 miles per hour, that of the gusts might +be equal or more. At one moment there might be a calm or the direction +of the wind even reversed, followed, the next moment, by a violent gust. +About the same minimum speed was desirable for security against gusts as +was demanded by other considerations. Sixty miles an hour was the least +figure desirable in an aeroplane, and this should be exceeded as much as +possible. Actually, the Wright machine had a speed of 38 miles per hour, +while Farman's Voisin machine flew at 45 miles per hour. + +Both machines were extremely sensitive to high winds, and the speaker, +in spite of newspaper reports to the contrary, had never seen either +flown in more than a gentle breeze. The damping out of the oscillations +of the flight path, discussed in the last lecture, increased with the +fourth power of the natural velocity of flight, and rapid damping +formed the easiest, and sometimes the only, defense against dangerous +oscillations. A machine just stable at 35 miles per hour would have +reasonably rapid damping if its speed were increased to 60 miles per +hour. + +Thinks Use Is Limited. + +It was, the lecturer proceeded, inconceivable that any very extended use +should be made of the aeroplane unless the speed was much greater than +that of the motor car. It might in special cases be of service, +apart from this increase of speed, as in the exploration of countries +destitute of roads, but it would have no general utility. With an +automobile averaging 25 to 35 miles per hour, almost any part of Europe, +Russia excepted, was attainable in a day's journey. A flying machine +of but equal speed would have no advantages, but if the speed could be +raised to 90 or 100 miles per hour, the whole continent of Europe +would become a playground, every part being within a daylight flight of +Berlin. Further, some marine craft now had speeds of 40 miles per hour, +and efficiently to follow up and report movements of such vessels an +aeroplane should travel at 60 miles per hour at least. Hence from +all points of view appeared the imperative desirability of very high +velocities of flight. The difficulties of achievement were, however, +great. + +Weight of Lightest Motors. + +As shown in the first lecture of his course, the resistance to motion +was nearly independent of the velocity, so that the total work done in +transporting a given weight was nearly constant. Hence the question of +fuel economy was not a bar to high velocities of flight, though should +these become excessive, the body resistance might constitute a large +proportion of the total. The horsepower required varied as the +velocity, so the factor governing the maximum velocity of flight was +the horsepower that could be developed on a given weight. At present the +weight per horsepower of feather-weight motors appeared to range from +2 1/4 pounds up to 7 pounds per brake horsepower, some actual figures +being as follows: + + Antoinette........ 5 lbs. + Fiat.............. 3 lbs. + Gnome....... Under 3 lbs. + Metallurgic....... 8 lbs. + Renault........... 7 lbs. + Wright.............6 lbs. + +Automobile engines, on the other hand, commonly weighed 12 pounds to 13 +pounds per brake horsepower. + +For short flights fuel economy was of less importance than a saving +in the weight of the engine. For long flights, however, the case +was different. Thus, if the gasolene consumption was 1/2 pound per +horsepower hour, and the engine weighed 3 pounds per brake horsepower, +the fuel needed for a six-hour flight would weigh as much as the engine, +but for half an hour's flight its weight would be unimportant. + +Best Means of Propulsion. + +The best method of propulsion was by the screw, which acting in air +was subject to much the same conditions as obtained in marine work. +Its efficiency depended on its diameter and pitch and on its position, +whether in front of or behind the body propelled. From this theory +of dynamic support, Mr. Lanchester proceeded, the efficiency of each +element of a screw propeller could be represented by curves such as were +given in his first lecture before the society, and from these curves the +over-all efficiency of any proposed propeller could be computed, by mere +inspection, with a fair degree of accuracy. These curves showed that the +tips of long-bladed propellers were inefficient, as was also the portion +of the blade near the root. In actual marine practice the blade from +boss to tip was commonly of such a length that the over-all efficiency +was 95 per cent of that of the most efficient element of it. + +Advocates Propellers in Rear. + +From these curves the diameter and appropriate pitch of a screw could +be calculated, and the number of revolutions was then fixed. Thus, for a +speed of 80 feet per second the pitch might come out as 8 feet, in which +case the revolutions would be 600 per minute, which might, however, be +too low for the motor. It was then necessary either to gear down the +propeller, as was done in the Wright machine, or, if it was decided to +drive it direct, to sacrifice some of the efficiency of the propeller. +An analogous case arose in the application of the steam turbine to the +propulsion of cargo boats, a problem as yet unsolved. The propeller +should always be aft, so that it could abstract energy from the wake +current, and also so that its wash was clear of the body propelled. The +best possible efficiency was about 70 per cent, and it was safe to rely +upon 66 per cent. + +Benefits of Soaring Flight. + +There was, Mr. Lanchester proceeded, some possibility of the aeronaut +reducing the power needed for transport by his adopting the principle of +soaring flight, as exemplified by some birds. There were, he continued, +two different modes of soaring flight. In the one the bird made use of +the upward current of air often to be found in the neighborhood of steep +vertical cliffs. These cliffs deflected the air upward long before it +actually reached the cliff, a whole region below being thus the seat of +an upward current. Darwin has noted that the condor was only to be found +in the neighborhood of such cliffs. Along the south coast also the gulls +made frequent use of the up currents due to the nearly perpendicular +chalk cliffs along the shore. + +In the tropics up currents were also caused by temperature differences. +Cumulus clouds, moreover, were nearly always the terminations of such +up currents of heated air, which, on cooling by expansion in the upper +regions, deposited their moisture as fog. These clouds might, perhaps, +prove useful in the future in showing the aeronaut where up currents +were to be found. Another mode of soaring flight was that adopted by +the albatross, which took advantage of the fact that the air moved +in pulsations, into which the bird fitted itself, being thus able to +extract energy from the wind. Whether it would be possible for the +aeronaut to employ a similar method must be left to the future to +decide. + +Main Difficulties in Aviation. + +In practical flight difficulties arose in starting and in alighting. +There was a lower limit to the speed at which the machine was stable, +and it was inadvisable to leave the ground till this limit was attained. +Similarly, in alighting it was inexpedient to reduce the speed below the +limit of stability. This fact constituted a difficulty in the adoption +of high speeds, since the length of run needed increased in proportion +to the square of the velocity. This drawback could, however, be +surmounted by forming starting and alighting grounds of ample size. +He thought it quite likely in the future that such grounds would be +considered as essential to the flying machine as a seaport was to an +ocean-going steamer or as a road was to the automobile. + +Requisites of Flying Machine. + +Flying machines were commonly divided into monoplanes and biplanes, +according as they had one or two supporting surfaces. The distinction +was not, however, fundamental. To get the requisite strength some +form of girder framework was necessary, and it was a mere question of +convenience whether the supporting surface was arranged along both +the top and the bottom of this girder, or along the bottom only. The +framework adopted universally was of wood braced by ties of pianoforte +wire, an arrangement giving the stiffness desired with the least +possible weight. Some kind of chassis was also necessary. + + + +CHAPTER XXIII. AMATEURS MAY USE WRIGHT PATENTS. + +Owing to the fact that the Wright brothers have enjoined a number of +professional aviators from using their system of control, amateurs have +been slow to adopt it. They recognize its merits, and would like to use +the system, but have been apprehensive that it might involve them in +litigation. There is no danger of this, as will be seen by the following +statement made by the Wrights: + +What Wright Brothers Say. + +"Any amateur, any professional who is not exhibiting for money, is at +liberty to use our patented devices. We shall be glad to have them do +so, and there will be no interference on our part, by legal action, or +otherwise. The only men we proceed against are those who, without our +permission, without even asking our consent, coolly appropriate the +results of our labors and use them for the purpose of making money. +Curtiss, Delagrange, Voisin, and all the rest of them who have used our +devices have done so in money-making exhibitions. So long as there +is any money to be made by the use of the products of our brains, we +propose to have it ourselves. It is the only way in which we can get +any return for the years of patient work we have given to the problem of +aviation. On the other hand, any man who wants to use these devices for +the purpose of pleasure, or the advancement of science, is welcome to do +so, without money and without price. This is fair enough, is it not?" + +Basis of the Wright Patents. + +In a flying machine a normally flat aeroplane having lateral marginal +portions capable of movement to different positions above or below the +normal plane of the body of the aeroplane, such movement being about +an axis transverse to the line of flight, whereby said lateral marginal +portions may be moved to different angles relatively to the normal +plane of the body of the aeroplane, so as to present to the atmosphere +different angles of incidence, and means for so moving said lateral +marginal portions, substantially as described. + +Application of vertical struts near the ends having flexible joints. + +Means for simultaneously imparting such movement to said lateral +portions to different angles relatively to each other. + +Refers to the movement of the lateral portions on the same side to the +same angle. + +Means for simultaneously moving vertical rudder so as to present to +the wind that side thereof nearest the side of the aeroplane having the +smallest angle of incidence. + +Lateral stability is obtained by warping the end wings by moving the +lever at the right hand of the operator, connection being made by wires +from the lever to the wing tips. The rudder may also be curved or warped +in similar manner by lever action. + +Wrights Obtain an Injunction. + +In January, 1910, Judge Hazel, of the United States Circuit Court, +granted a preliminary injunction restraining the Herring-Curtiss +Co., and Glenn H. Curtiss, from manufacturing, selling, or using for +exhibition purposes the machine known as the Curtiss aeroplane. The +injunction was obtained on the ground that the Curtiss machine is an +infringement upon the Wright patents in the matter of wing warping and +rudder control. + +It is not the purpose of the authors to discuss the subject pro or con. +Such discussion would have no proper place in a volume of this kind. It +is enough to say that Curtiss stoutly insists that his machine is not +an infringement of the Wright patents, although Judge Hazel evidently +thinks differently. + +What the Judge Said. + +In granting the preliminary injunction the judge said: + +"Defendants claim generally that the difference in construction of their +apparatus causes the equilibrium or lateral balance to be maintained and +its aerial movement secured upon an entirely different principle from +that of complainant; the defendants' aeroplanes are curved, firmly +attached to the stanchions and hence are incapable of twisting or +turning in any direction; that the supplementary planes or so-called +rudders are secured to the forward stanchion at the extreme lateral ends +of the planes and are adjusted midway between the upper and lower +planes with the margins extending beyond the edges; that in moving the +supplementary planes equal and uniform angles of incidence are presented +as distinguished from fluctuating angles of incidence. Such claimed +functional effects, however, are strongly contradicted by the expert +witness for complainant. + +Similar to Plan of Wrights. + +"Upon this contention it is sufficient to say that the affidavits for +the complainant so clearly define the principle of operation of the +flying machines in question that I am reasonably satisfied that there +is a variableness of the angle of incidence in the machine of defendants +which is produced when a supplementary plane on one side is tilted +or raised and the other stimultaneously tilted or lowered. I am also +satisfied that the rear rudder is turned by the operator to the side +having the least angle of incidence and that such turning is done at the +time the supplementary planes are raised or depressed to prevent tilting +or upsetting the machine. On the papers presented I incline to the view, +as already indicated, that the claims of the patent in suit should be +broadly construed; and when given such construction, the elements of +the Wright machine are found in defendants' machine performing the +same functional result. There are dissimilarities in the defendants' +structure--changes of form and strengthening of parts--which may be +improvements, but such dissimilarities seem to me to have no bearing +upon the means adopted to preserve the equilibrium, which means are the +equivalent of the claims in suit and attain an identical result. + +Variance From Patent Immaterial. + +"Defendants further contend that the curved or arched surfaces of the +Wright aeroplanes in commercial use are departures from the patent, +which describes 'substantially flat surfaces,' and that such a +construction would be wholly impracticable. The drawing, Fig. 3, +however, attached to the specification, shows a curved line inward of +the aeroplane with straight lateral edges, and considering such drawing +with the terminology of the specification, the slight arching of the +surface is not thought a material departure; at any rate, the patent in +issue does not belong to the class of patents which requires narrowing +to the details of construction." + +"June Bug" First Infringement. + +Referring to the matter of priority, the judge said: + +"Indeed, no one interfered with the rights of the patentees by +constructing machines similar to theirs until in July, 1908, when +Curtiss exhibited a flying machine which he called the 'June Bug.' He +was immediately notified by the patentees that such machine with its +movable surfaces at the tips of wings infringed the patent in suit, and +he replied that he did not intend to publicly exhibit the machine for +profit, but merely was engaged in exhibiting it for scientific purposes +as a member of the Aerial Experiment Association. To this the patentees +did not object. Subsequently, however, the machine, with supplementary +planes placed midway between the upper and lower aeroplanes, was +publicly exhibited by the defendant corporation and used by Curtiss in +aerial flights for prizes and emoluments. It further appears that the +defendants now threaten to continue such use for gain and profit, and to +engage in the manufacture and sale of such infringing machines, thereby +becoming an active rival of complainant in the business of constructing +flying machines embodying the claims in suit, but such use of the +infringing machines it is the duty of this court, on the papers +presented, to enjoin. + +"The requirements in patent causes for the issuance of an injunction +pendente lite--the validity of the patent, general acquiescence by the +public and infringement by the defendants--are so reasonably clear that +I believe if not probable the complainant may succeed at final hearing, +and therefore, status quo should be preserved and a preliminary +injunction granted. + +"So ordered." + +Points Claimed By Curtiss. + +That the Herring-Curtiss Co. will appeal is a certainty. Mr. Emerson R. +Newell, counsel for the company, states its case as follows: + +"The Curtiss machine has two main supporting surfaces, both of which are +curved * * * and are absolutely rigid at all times and cannot be moved, +warped or distorted in any manner. The front horizontal rudder is used +for the steering up or down, and the rear vertical rudder is used only +for steering to the right or left, in the same manner as a boat is +steered by its rudder. The machine is provided at the rear with a fixed +horizontal surface, which is not present in the machine of the patent, +and which has a distinct advantage in the operation of defendants' +machine, as will be hereafter discussed. + +Does Not Warp Main Surface. + +"Defendants' machine does not use the warping of the main supporting +surfaces in restoring the lateral equilibrium, but has two comparatively +small pivoted balancing surfaces or rudders. When one end of the machine +is tipped up or down from the normal, these planes may be thrown in +opposite directions by the operator, and so steer each end of the +machine up or down to its normal level, at which time tension upon them +is released and they are moved back by the pressure of the wind to their +normal position. + +Rudder Used Only For Steering. + +"When defendants' balancing surfaces are moved they present equal angles +of incidence to the normal rush of air and equal resistances, at each +side of the machine, and there is therefore no tendency to turn around a +vertical axis as is the case of the machine of the patent, consequently +no reason or necessity for turning the vertical rear rudder in +defendants' machine to counteract any such turning tendency. At any +rate, whatever may be the theories in regard to this matter, the fact is +that the operator of defendants' machine does not at any time turn his +vertical rudder to counteract any turning tendency clue to the side +balancing surfaces, but only uses it to steer the machine the same as a +boat is steered." + +Aero Club Recognizes Wrights. + +The Aero Club of America has officially recognized the Wright patents. +This course was taken following a conference held April 9th, 1910, +participated in by William Wright and Andrew Freedman, representing the +Wright Co., and the Aero Club's committee, of Philip T. Dodge, W. W. +Miller, L. L. Gillespie, Wm. H. Page and Cortlandt F. Bishop. + +At this meeting arrangements were made by which the Aero Club recognizes +the Wright patents and will not give its section to any open meet +where the promoters thereof have not secured a license from the Wright +Company. + +The substance of the agreement was that the Aero Club of America +recognizes the rights of the owners of the Wright patents under +the decisions of the Federal courts and refuses to countenance the +infringement of those patents as long as these decisions remain in +force. + +In the meantime, in order to encourage aviation, both at home and +abroad, and in order to permit foreign aviators to take part in aviation +contests in this country it was agreed that the Aero Club of America, as +the American representative of the International Aeronautic Federation, +should approve only such public contests as may be licensed by the +Wright Company and that the Wright Company, on the other hand, should +encourage the holding of open meets or contests where ever approved as +aforesaid by the Aero Club of America by granting licenses to promoters +who make satisfactory arrangements with the company for its compensation +for the use of its patents. At such licensed meet any machine of any +make may participate freely without securing any further license or +permit. The details and terms of all meets will be arranged by the +committee having in charge the interests of both organizations. + + + +CHAPTER XXIV. HINTS ON PROPELLER CONSTRUCTION. + +Every professional aviator has his own ideas as to the design of +the propeller, one of the most important features of flying-machine +construction. While in many instances the propeller, at a casual glance, +may appear to be identical, close inspection will develop the fact +that in nearly every case some individual idea of the designer has been +incorporated. Thus, two propellers of the two-bladed variety, while of +the same general size as to length and width of blade, will vary greatly +as to pitch and "twist" or curvature. + +What the Designers Seek. + +Every designer is seeking for the same result--the securing of the +greatest possible thrust, or air displacement, with the least possible +energy. + +The angles of any screw propeller blade having a uniform or true pitch +change gradually for every increased diameter. In order to give a +reasonably clear explanation, it will be well to review in a primary way +some of the definitions or terms used in connection with and applied to +screw propellers. + +Terms in General Use. + +Pitch.--The term "pitch," as applied to a screw propeller, is the +theoretical distance through which it would travel without slip in one +revolution, and as applied to a propeller blade it is the angle at +which the blades are set so as to enable them to travel in a spiral path +through a fixed distance theoretically without slip in one revolution. + +Pitch speed.--The term "pitch speed" of a screw propeller is the speed +in feet multiplied by the number of revolutions it is caused to make +in one minute of time. If a screw propeller is revolved 600 times +per minute, and if its pitch is 7 ft., then the pitch speed of such a +propeller would be 7x600 revolutions, or 4200 ft. per minute. + +Uniform pitch.--A true pitch screw propeller is one having its blades +formed in such a manner as to enable all of its useful portions, from +the portion nearest the hub to its outer portion, to travel at a uniform +pitch speed. Or, in other words, the pitch is uniform when the projected +area of the blade is parallel along its full length and at the same time +representing a true sector of a circle. + +All screw propellers having a pitch equal to their diameters have the +same angle for their blades at their largest diameter. + +When Pitch Is Not Uniform. + +A screw propeller not having a uniform pitch, but having the same angle +for all portions of its blades, or some arbitrary angle not a true +pitch, is distinguished from one having a true pitch in the variation of +the pitch speeds that the various portions of its blades are forced to +travel through while traveling at its maximum pitch speed. + +On this subject Mr. R. W. Jamieson says in Aeronautics: + +"Take for example an 8-foot screw propeller having an 8-foot pitch at +its largest diameter. If the angle is the same throughout its entire +blade length, then all the porions of its blades approaching the hub +from its outer portion would have a gradually decreasing pitch. The +2-foot portion would have a 2-foot pitch; the 3-foot portion a 3-foot +pitch, and so on to the 8-foot portion which would have an 8-foot pitch. +When this form of propeller is caused to revolve, say 500 r.p.m., the +8-foot portion would have a calculated pitch speed of 8 feet by 500 +revolutions, or 4,000 feet per min.; while the 2-foot portion would have +a calculated pitch speed of 500 revolutions by 2 feet, or 1,000 feet per +minute. + +Effect of Non-Uniformity. + +"Now, as all of the portions of this type of screw propeller must travel +at some pitch speed, which must have for its maximum a pitch speed +in feet below the calculated pitch speed of the largest diameter, it +follows that some portions of its blades would perform useful work +while the action of the other portions would be negative--resisting +the forward motion of the portions having a greater pitch speed. The +portions having a pitch speed below that at which the screw is traveling +cease to perform useful work after their pitch speed has been exceeded +by the portions having a larger diameter and a greater pitch speed. + +"We might compare the larger and smaller diameter portions of this form +of screw propeller, to two power-driven vessels connected with a line, +one capable of traveling 20 miles per hour, the other 10 miles per hour. +It can be readily understood that the boat capable of traveling 10 miles +per hour would have no useful effect to help the one traveling 20 miles +per hour, as its action would be such as to impose a dead load upon the +latter's progress." + +The term "slip," as applied to a screw propeller, is the distance +between its calculated pitch speed and the actual distance it travels +through under load, depending upon the efficiency and proportion of its +blades and the amount of load it has to carry. + +The action of a screw propeller while performing useful work might be +compared to a nut traveling on a threaded bolt; little resistance is +offered to its forward motion while it spins freely without load, but +give it a load to carry; then it will take more power to keep up its +speed; if too great a load is applied the thread will strip, and so +it is with a screw propeller gliding spirally on the air. A propeller +traveling without load on to new air might be compared to the nut +traveling freely on the bolt. It would consume but little power and it +would travel at nearly its calculated pitch speed, but give it work to +do and then it will take power to drive it. + +There is a reaction caused from the propeller projecting air backward +when it slips, which, together with the supporting effect of the blades, +combine to produce useful work or pull on the object to be carried. + +A screw propeller working under load approaches more closely to its +maximum efficiency as it carries its load with a minimum amount of slip, +or nearing its calculated pitch speed. + +Why Blades Are Curved. + +It has been pointed out by experiment that certain forms of curved +surfaces as applied to aeroplanes will lift more per horse power, per +unit of square foot, while on the other hand it has been shown that a +flat surface will lift more per horse power, but requires more area of +surface to do it. + +As a true pitch screw propeller is virtually a rotating aeroplane, a +curved surface may be advantageously employed when the limit of size +prevents using large plane surfaces for the blades. + +Care should be exercised in keeping the chord of any curve to be used +for the blades at the proper pitch angle, and in all cases propeller +blades should be made rigid so as to preserve the true angle and not be +distorted by centrifugal force or from any other cause, as flexibility +will seriously affect their pitch speed and otherwise affect their +efficiency. + +How to Determine Angle. + +To find the angle for the proper pitch at any point in the diameter of +a propeller, determine the circumference by multiplying the diameter by +3.1416, which represent by drawing a line to scale in feet. At the end +of this line draw another line to represent the desired pitch in feet. +Then draw a line from the point representing the desired pitch in feet +to the beginning of the circumference line. For example: + +If the propeller to be laid out is 7 feet in diameter, and is to have +a 7-foot pitch, the circumference will be 21.99 feet. Draw a diagram +representing the circumference line and pitch in feet. If this diagram +is wrapped around a cylinder the angle line will represent a true thread +7 feet in diameter and 7 feet long, and the angle of the thread will be +17 3/4 degrees. + +Relation of Diameter to Circumference. + +Since the areas of circles decrease as the diameter lessens, it follows +that if a propeller is to travel at a uniform pitch speed, the volume of +its blade displacement should decrease as its diameter becomes less, so +as to occupy a corresponding relation to the circumferences of larger +diameters, and at the same time the projected area of the blade must be +parallel along its full length and should represent a true sector of a +circle. + +Let us suppose a 7-foot circle to be divided into 20 sectors, one of +which represents a propeller blade. If the pitch is to be 7 feet, then +the greatest depth of the angle would be 1/20 part of the pitch, or 4 +2/10 inch. If the line representing the greatest depth of the angle is +kept the same width as it approaches the hub, the pitch will be uniform. +If the blade is set at an angle so its projected area is 1/20 part of +the pitch, and if it is moved through 20 divisions for one revolution, +it would have a travel of 7 feet. + + + +CHAPTER XXV. NEW MOTORS AND DEVICES. + +Since the first edition of this book was printed, early in 1910, there +has been a remarkable advance in the construction of aeroplane motors, +which has resulted in a wonderful decrease in the amount of surface area +from that formerly required. Marked gain in lightness and speed of +the motor has enabled aviators to get along, in some instances, with +one-quarter of the plane supporting area previously used. The first +Wright biplane, propelled by a motor of 25 h.p., productive of a fair +average speed of 30 miles an hour, had a plane surface of 538 square +feet. Now, by using a specially designed motor of 65 h. p., capable +of developing a speed of from 70 to 80 miles an hour, the Wrights are +enabled to successfully navigate a machine the plane area of which is +about 130 square feet. This apparatus is intended to carry only one +person (the operator). At Belmont Park, N. Y., the Wrights demonstrated +that the small-surfaced biplane is much faster, easier to manage in the +hands of a skilled manipulator, and a better altitude climber than the +large and cumbersome machines with 538 square feet of surface heretofore +used by them. + +In this may be found a practical illustration of the principle that +increased speed permits of a reduction in plane area in mathematical +ratio to the gain in speed. The faster any object can be made to move +through the air, the less will be the supporting surface required to +sustain a given weight. But, there is a limit beyond which the plane +surface cannot be reduced with safety. Regard must always be had to +the securing of an ample sustaining surface so that in case of motor +stoppage there will be sufficient buoyancy to enable the operator to +descend safely. + +The baby Wright used at the Belmont Park (N. Y.) aviation meet in the +fall of 1910, had a plane length of 19 feet 6 inches, and an extreme +breadth of 21 feet 6 inches, with a total surface area of 146 square +feet. It was equipped with a new Wright 8-cylinder motor of 60 h. p., +and two Wright propellers of 8 feet 6 inches diameter and 500 r. p. m. +It was easily the fastest machine at the meet. After the tests, Wilbur +Wright said: + +"It is our intention to put together a machine with specially designed +propellers, specially designed gears and a motor which will give us 65 +horsepower at least. We will then be able, after some experimental work +we are doing now, to send forth a machine that will make a new speed +record." + +In the new Wright machines the front elevating planes for up-and-down +control have been eliminated, and the movements of the apparatus are now +regulated solely by the rear, or "tail" control. + +A Powerful Light Motor. + +Another successful American aviation motor is the aeromotor, +manufactured by the Detroit Aeronautic Construction. Aeromotors are made +in four models as follows: + +Model 1.--4-cylinder, 30-40 h. p., weight 200 pounds. + +Model 2.--4-cylinder, (larger stroke and bore) 40-50 h. p., weight 225 +pounds. + +Model 3.--6-cylinder. 50-60 h. p., weight 210 pounds. + +Model 4.--6-cylinder, 60-75 h. p., weight 275 pounds. + +This motor is of the 4-cycle, vertical, water-cooled type. Roberts +Aviation Motor. + +One of the successful aviation motors of American make, is that produced +by the Roberts Motor Co., of Sandusky, Ohio. It is designed by E. W. +Roberts, M. E., who was formerly chief assistant and designer for Sir +Hiram Maxim, when the latter was making his celebrated aeronautical +experiments in England in 1894-95. This motor is made in both the +4- and 6-cylinder forms. The 4-cylinder motor weighs complete with Bosch +magneto and carbureter 165 pounds, and will develop 40 actual brake +h. p. at 1,000 r. p. m., 46 h. p. at 1,200 and 52 h. p. at 1,400. The +6-cylinder weighs 220 pounds and will develop 60 actual brake h. p. at +1,000 r. p. m., 69 h. p. at 1,200 and 78 h. p. at 1,500. + +Extreme lightness has been secured by doing away with all superfluous +parts, rather than by a shaving down of materials to a dangerous +thinness. For example, there is neither an intake or exhaust manifold on +the motor. The distributing valve forms a part of the crankcase as +does the water intake, and the gear pump. Magnalium takes the place of +aluminum in the crankcase, because it is not only lighter but stronger +and can be cast very thin. The crankshaft is 2 1/2-inch diameter with a +2 1/4-inch hole, and while it would be strong enough in ordinary 40 +per cent carbon steel it is made of steel twice the strength of that +customarily employed. Similar care has been exercised on other parts and +the result is a motor weighing 4 pounds per h. p. + +The Rinek Motor. + +The Rinek aviation motor, constructed by the Rinek Aero Mfg. Co., of +Easton, Pa., is another that is meeting with favor among aviators. Type +B-8 is an 8-cylinder motor, the cylinders being set at right angles, +on a V-shaped crank case. It is water cooled, develops 50-60 h. p., the +minimum at 1,220 r. p. m., and weighs 280 pounds with all accessories. +Type B-4, a 4-cylinder motor, develops 30 h. p. at 1,800 r. p. m., and +weighs 130 pounds complete. The cylinders in both motors are made of +cast iron with copper water jackets. + +The Overhead Camshaft Boulevard. + +The overhead camshaft Boulevard is still another form of aviation motor +which has been favorably received. This is the product of the Boulevard +Engine Co., of St. Louis. It is made with 4 and 8 cylinders. The former +develops 30-35 h. p. at 1,200 r. p. m., and weighs 130 pounds. The +8-cylinder motor gives 60-70 h. p. at 1,200 r. p. m., and weighs 200 +pounds. Simplicity of construction is the main feature of this motor, +especially in the manipulation of the valves. + + + +CHAPTER XXVI. MONOPLANES, TRIPLANES, MULTIPLANES. + +Until recently, American aviators had not given serious attention to +any form of flying machines aside from biplanes. Of the twenty-one +monoplanes competing at the International meet at Belmont Park, N. Y., +in November, 1910, only three makes were handled by Americans. Moissant +and Drexel navigated Bleriot machines, Harkness an Antoinette, and Glenn +Curtiss a single decker of his own construction. On the other hand the +various foreign aviators who took part in the meet unhesitatingly gave +preference to monoplanes. + +Whatever may have been the cause of this seeming prejudice against +the monoplane on the part of American air sailors, it is slowly being +overcome. When a man like Curtiss, who has attained great success with +biplanes, gives serious attention to the monoplane form of construction +and goes so far as to build and successfully operate a single surface +machine, it may be taken for granted that the monoplane is a fixture in +this country. + +Dimensions of Monoplanes. + +The makes, dimensions and equipment of the various monoplanes used at +Belmont Park are as follows: + +Bleriot--(Moissant, operator)--plane length 23 feet, extreme breadth 28 +feet, surface area 160 square feet, 7-cylinder, 50 h. p. Gnome engine, +Chauviere propeller, 7 feet 6 inches diameter, 1,200 r. p. m. + +Bleriot--(Drexel, operator)--exactly the same as Moissant's machine. + +Antoinette--(Harkness, operator)--plane length 42 feet, extreme breadth +46 feet, surface area 377 square feet, Emerson 6-cylinder, 50 h. p. +motor, Antoinette propeller, 7 feet 6 inches diameter, 1,200 r. p. m. + +Curtiss--(Glenn H. Curtiss, operator)--plane length 25 feet, extreme +breadth 26 feet, surface area 130 square feet, Curtiss 8-cylinder, 60 h. +p. motor, Paragon propeller, 7 feet in diameter, 1,200 r. p. m. + +With one exception Curtiss had the smallest machine of any of those +entering into competition. The smallest was La Demoiselle, made by +Santos-Dumont, the proportions of which were: plane length 20 feet, +extreme breadth 18 feet, surface area 100 square feet, Clement-Bayard +2-cylinder, 30 h. p. motor, Chauviere propeller, 6 feet 6 inches in +diameter, 1,100 r. p. m. + +Winnings Made with Monoplanes. + +Operators of monoplanes won a fair share of the cash prizes. They won +$30,283 out of a total of $63,250, to say nothing about Grahame-White's +winnings. The latter won $13,600, but part of his winning flights were +made in a Bleriot monoplane, and part in a Farman machine. Aside from +Grahame-White the winnings were divided as follows: Moissant (Bleriot) +$13,350; Latham (Antoinette) $8,183; Aubrun (Bleriot) $2,400; De Lesseps +(Bleriot) $2,300; Drexel (Bleriot) $1,700; Radley (Bleriot) $1,300; +Simon (Bleriot) $750; Andemars (Clement-Bayard) $100; Barrier (Bleriot) +$100. + +Out of a total of $30,283, operators of Bleriot machines won $21,900, +again omitting Grahame-White's share. If the winnings with monoplane and +biplane could be divided so as to show the amount won with each type +of machine the credit side of the Bleriot account would be materially +enlarged. + +The Most Popular Monoplanes. + +While the number of successful monoplanes is increasing rapidly, and +there is some feature of advantage in nearly all the new makes, interest +centers chiefly in the Santos-Dumont, Antoinette and Bleriot machines. +This is because more has been accomplished with them than with any of +the others, possibly because they have had greater opportunities. + +For the guidance of those who may wish to build a machine of the +monoplane type after the Santos-Dumont or Bleriot models, the following +details will be found useful. + +Santos-Dumont--The latest production of this maker is called the "No. 20 +Baby." It is of 18 feet spread, and 20 feet over all in depth. It stands +4 feet 2 inches in height, not counting the propeller. When this latter +is in a vertical position the extreme height of the machine is 7 feet +5 inches. It is strictly a one-man apparatus. The total surface area +is 115 square feet. The total weight of the monoplane with engine and +propeller is 352 pounds. Santos-Dumont weighs 110 pounds, so the entire +weight carried while in flight is 462 pounds, or about 3.6 pounds per +square foot of surface. + +Bamboo is used in the construction of the body frame, and also for the +frame of the tail. The body frame consists of three bamboo poles about +2 inches in diameter at the forward end and tapering to about 1 inch at +the rear. These poles are jointed with brass sockets near the rear of +the main plane so they may be taken apart easily for convenience in +housing or transportation. The main plane is built upon four transverse +spars of ash, set at a slight dihedral angle, two being placed on each +side of the central bamboo. These spars are about 2 inches wide by 1 +1/8-inch deep for a few feet each side of the center of the machine, and +from there taper down to an inch in depth at the center bamboo, and at +their outer ends, but the width remains the same throughout their entire +length. The planes are double surfaced with silk and laced above and +below the bamboo ribs which run fore and aft under the main spars and +terminate in a forked clip through which a wire is strung for lacing on +the silk. The tail consists of a horizontal and vertical surface placed +on a universal joint about 10 feet back of the rear edge of the main +plane. Both of these surfaces are flat and consist of a silk covering +stretched upon bamboo ribs. The horizontal surface is 6 feet 5 inches +across, and 4 feet 9 inches from front to back. The vertical surface +is of the same width (6 feet 5 inches) but is only 3 feet 7 inches +from front to back. All the details of construction are shown in the +accompanying illustration. + +Power is furnished by a very light (110 pounds) Darracq motor, of the +double-opposed-cylinder type. It has a bore of 4.118 inches, and stroke +of 4.724 inches, runs at 1,800 r. p. m., and with a 6 1/2-foot propeller +develops a thrust of 242 1/2 pounds when the monoplane is held steady. + +Bleriot--No. XI, the latest of the Bleriot productions, and the greatest +record maker of the lot, is 28 feet in spread of main plane, and depth +of 6 feet in largest part. This would give a main surface of 168 square +feet, but as the ends of the plane are sharply tapered from the rear, +the actual surface is reduced to 150 square feet. Projecting from +the main frame is an elongated tail (shown in the illustration) which +carries the horizontal and vertical rudders. The former is made in three +sections. The center piece is 6 feet 1 inch in spread, and 2 feet 10 +inches in depth, containing 17 square feet of surface. The end sections, +which are made movable for warping purposes, are each 2 feet 10 inches +square, the combined surface area in the entire horizontal rudder +being 33 square feet. The vertical rudder contains 4 1/2 square feet of +surface, making the entire supporting area 187 1/2 square feet. + +From the outer end of the propeller shaft in front to the extreme rear +edge of the vertical rudder, the machine is 25 feet deep. Deducting +the 6-foot depth of the main plane leaves 19 feet as the length of the +rudder beam and rudders. The motor equipment consists of a 3-cylinder, +air-cooled engine of about 30 h. p. placed at the front end of the body +frame, and carrying on its crankshaft a two-bladed propeller 6 feet 8 +inches in diameter. The engine speed is about 1,250 r. p. m. at which +the propeller develops a thrust of over 200 pounds. + +The Bleriot XI complete weighs 484 pounds, and with operator and fuel +supply ready for a 25- or 30-mile flight, 715 pounds. One peculiarity of +the Bleriot construction is that, while the ribs of the main plane are +curved, there is no preliminary bending of the pieces as in other forms +of construction. Bleriot has his rib pieces cut a little longer than +required and, by springing them into place, secures the necessary +curvature. A good view of the Bleriot plane framework is given on page +63. + +Combined Triplane and Biplane. + +At Norwich, Conn., the Stebbins-Geynet Co., after several years of +experiment, has begun the manufacture of a combination triplane and +biplane machine. The center plane, which is located about midway +between the upper and lower surfaces, is made removable. The change +from triplane to biplane, or vice versa, may be readily made in a few +minutes. The constructors claim for this type of air craft a large +supporting surface area with the minimum of dimensions in planes. +Although this machine has only 24-foot spread and is only 26 feet over +all, its total amount of supporting area is 400 square feet; weight, 600 +pounds in flying order, and lifting capacity approximately 700 pounds +more. + +The frame is made entirely of a selected grade of Oregon spruce, +finished down to a smooth surface and varnished. All struts are +fish-shaped and set in aluminum sockets, which are bolted to top and +lower beams with special strong bolts of small diameter. The middle +plane is set inside the six uprights and held in place by aluminum +castings. A flexible twisted seven-strand wire cable and Stebbins-Geynet +turnbuckles are used for trussing. + +The top plane is in three sections, laced together. It has a 24-foot +spread and is 7 feet in depth. The middle plane is in two sections each +of 7 1/2 feet spread and 6 feet in depth. The center ends of the middle +plane sections do not come within 5 feet of joining, this open space +being left for the engine. The bottom plane is of 16 feet spread and 5 +feet in depth. It will thus be seen that the planes overhang one another +in depth, the bottom one being the smallest in this respect. The planes +are set at an angle of 9 degrees, and there is a clear space of 3 1/2 +feet between each, making the total distance from the bottom to the top +plane a trifle over 7 feet. The total supporting surface in the main +planes is 350 square feet. By arranging the three plane surfaces at +an angle as described and varying their size, the greatest amount of +lifting area is secured above the center of gravity, and the greatest +weight carried below. + +The ribs are made of laminated spruce, finished down to 1/2x3/4-inch +cross section dimensions, with a curvature of about 1 in 20, and +fastened to the beams with special aluminum castings. Number 2 Naiad +aeroplane cloth is used in covering the planes, with pockets sewn in for +the ribs. + +Two combination elevating rudders are set up well in front, each having +18 square feet of supporting area. These rudders are arranged to work +in unison, independently, or in opposite directions. In the Model B +machine, there are also two small rear elevating rudders, which work in +unison with the front rudders. One vertical rudder of 10 square feet is +suspended in the rear of a small stationary horizontal plane in Model A, +while the vertical rudder on Model B is only 6 square feet in size. The +elevating rudders are arranged so as to act as stabilizing planes when +the machine is in flight. The wing tips are held in place with a special +two-piece casting which forms a hinge, and makes a quick detachable +joint. Wing tips are also used in balancing. + +Model A is equipped with a Cameron 25-30 h. p., 4-cylinder, air-cooled +motor. On Model B a Holmes rotary 7-cylinder motor of 4x4-inch bore and +stroke is used. + +Positive control is secured by use of the Stebbins-Geynet "auto-control" +system. A pull or push movement operates the elevating rudders, while +the balancing is done by means of side movements or slight turns. The +rear vertical rudder is manipulated by means of a foot lever. + +New Cody Biplane. + +Among the comparatively new biplanes is one constructed by Willard F. +Cody, of London, Eng., the principal distinctive feature of which is an +automatic control which works independently of the hand levers. For the +other control a long lever carrying a steering wheel furnishes all the +necessary control movements, there being no footwork at all. The lever +is universally jointed and when moved fore and aft operates the two +ailerons as if they were one; when the shaft is rotated it moves the +tail as a whole. The horizontal tail component is immovable. When the +lever is moved from side to side it works not only the ailerons and +the independent elevators, but also through a peculiar arrangement, the +vertical rear rudder as well. + +The spread of the planes is 46 feet 6 inches and the width 6 feet 6 +inches. The ailerons jut out 1 foot 6 inches on each side of the machine +and are 13 feet 6 inches long. The cross-shaped tail is supported by an +outrigger composed of two long bamboos and of this the vertical plane +is 9 feet by 4 feet, while the horizontal plane is 8 feet by 4 feet. The +over-all length of the machine is 36 feet. The lifting surface is 857 +square feet. It will weigh, with a pilot, 1,450 pounds. The distance +between the main planes is 8 feet 6 inches, which is a rather notable +feature in this flyer. + +The propeller has a diameter of 11 feet and 2 inches with a 13-foot +6-inch pitch; it is driven at 560 revolutions by a chain, and the gear +reduction between the chain and propeller shaft is two to one. + +The machine from elevator to tail plane bristles in original points. The +hump in the ribs has been cut away entirely, so that although the plane +is double surfaced, the surfaces are closest together at a point which +approximates the center of pressure. The plane is practically of two +stream-line forms, of which one is the continuation of the other. +This construction, claims the inventor, will give increased lift, and +decreased head resistance. The trials substantiate this, as the angle of +incidence in flying is only about one in twenty-six. + +The ribs in the main planes are made of strips of silver spruce one-half +by one-half inch, while those in the ailerons are solid and one-fourth +inch thick. In the main planes the fabric is held down with thin wooden +fillets. Cody's planes are noted for their neatness, rigidity and +smoothness. Pegamoid fabric is used throughout. + +Pressey Automatic Control. + +Another ingenious system of automatic control has been perfected by Dr. +J. B. Pressey, of Newport News, Va. The aeroplane is equipped with a +manually operated, vertical rudder, (3), at the stern, and a horizontal, +manually operated, front control, (4), in front. At the ends of the main +plane, and about midway between the upper and lower sections thereof, +there are supplemental planes, (5). + +In connection with these supplemental planes (5), there is employed a +gravity influenced weight, the aviator in his seat, for holding them in +a horizontal, or substantially horizontal, position when the main plane +is traveling on an even keel; and for causing them to tip when the main +plane dips laterally, to port or starboard, the planes (5) having +a lifting effect upon the depressed end of the main plane, and a +depressing effect upon the lifted end of the main plane, so as to +correct such lateral dip of the main plane, and restore it to an even +keel. To the forward, upper edge of planes (5) connection is made by +means of rod (13) to one arm of a bellcrank lever, (14) the latter being +pivotally mounted upon a fore and aft pin (15), supported from the main +plane; and the other arms of the port and starboard bellcrank levers +(16), are connected by rod (17), which has an eye (18), for receiving +the segmental rod (19), secured to and projecting from cross bar on seat +supporting yoke (7). When, therefore, the main plane tips downwardly on +the starboard side, the rod (17) will be moved bodily to starboard, and +the starboard balancing plane (5) will be inclined so as to raise its +forward edge and depress its rear edge, while, at the same time, the +port balancing plane (5), will be inclined so as to depress its forward +edge, and raise its rear edge, thereby causing the starboard balancing +plane to exert a lifting effect, and the port balancing plane to exert a +depressing effect upon the main plane, with the result of restoring the +main plane to an even keel, at which time the balancing planes (5), will +have resumed their normal, horizontal position. + +When the main plane dips downwardly on the port side, a reverse action +takes place, with the like result of restoring the main plane to an even +keel. In order to correct forward and aft dip of the main plane, fore +and aft balancing planes (20) and (23) are provided. These planes are +carried by transverse rock shafts, which may be pivotally mounted in +any suitable way, upon structures carried by main plane. In the present +instance, the forward balancing plane is pivotally mounted in extensions +(21) of the frame (22) which carries the forward, manually operated, +horizontal ascending and descending plane + +It is absolutely necessary, in making a turn with an aeroplane, if that +turn is to be made in safety, that the main plane shall be inclined, or +"banked," to a degree proportional to the radius of the curve and to the +speed of the aeroplane. Each different curve, at the same speed, demands +a different inclination, as is also demanded by each variation in speed +in rounding like curves. This invention gives the desired result with +absolute certainty. + +The Sellers' Multiplane. + +Another innovation is a multiplane, or four-surfaced machine, built and +operated by M. B. Sellers, formerly of Grahn, Ky., but now located at +Norwood, Ga. Aside from the use of four sustaining surfaces, the novelty +in the Sellers machine lies in the fact that it is operated successfully +with an 8 h. p. motor, which is the smallest yet used in actual flight. +In describing his work, Mr. Sellers says his purpose has been to develop +the efficiency of the surfaces to a point where flight may be obtained +with the minimum of power and, judging by the results accomplished, +he has succeeded. In a letter written to the authors of this book, Mr. +Sellers says: + +"I dislike having my machine called a quadruplane, because the number of +planes is immaterial; the distinctive feature being the arrangement +of the planes in steps; a better name would be step aeroplane, or step +plane. + +"The machine as patented, comprises two or more planes arranged in step +form, the highest being in front. The machine I am now using has four +planes 3 ft. x 18 ft.; total about 200 square feet; camber (arch) 1 in +16. + +"The vertical keel is for lateral stability; the rudder for direction. +This is the first machine (so far as I know) to have a combination +of wheels and runners or skids (Oct. 1908). The wheels rise up +automatically when the machine leaves the ground, so that it may alight +on the runners. + +"A Duthirt & Chalmers 2-cylinder opposed, 3 1/8-inch engine was used +first, and several hundred short flights were made. The engine gave +four brake h. p., which was barely sufficient for continued flight. The +aeroplane complete with this engine weighed 78 pounds. The engine now +used is a Bates 3 5/8-inch, 2-cylinder opposed, showing 8 h. p., and +apparently giving plenty of power. The weight of aeroplane with this +engine is now 110 pounds. Owing to poor grounds only short flights have +been made, the longest to date (Dec. 31, 1910) being about 1,000 feet. + +"In building the present machine, my object was to produce a safe, slow, +light, and small h. p. aeroplane, a purpose which I have accomplished." + + + +CHAPTER XXVII. 1911 AEROPLANE RECORDS. + +THE WORLD AT LARGE. + +Greatest Speed Per Hour, Whatever Length of Flight, Aviator Alone--E. +Nieuport, Mourmelon, France, June 21, Nieuport Machine, 82.72 miles; +with one passenger, E. Nieuport, Moumlelon, France, June 12, Nieuport +Machine, 67.11 miles; with two passengers, E. Nieuport, Mourmelon, +France, March 9, Nieuport Machine, 63.91 miles; with three passengers, +G. Busson, Rheims, France, March 10, Deperdussin Machine, 59.84 miles; +with four passengers, G. Busson, Rheims, France, March 10, Deperdussin +Machine, 54.21 miles. + +Greatest Distance Aviator Alone--G. Fourny, no stops, Buc, France, +September 2, M. Farman Machine, 447.01 miles; E. Helen, three stops, +Etampes, France, September 8, Nieuport Machine, 778.45 miles; with +one passenger, Lieut. Bier, Austria, October 2, Etrich Machine, 155.34 +miles; with two passengers, Lieut. Bier, Austria, October 4, Etrich +Machine, 69.59 miles; with three passengers, G. Busson, Rheims, France, +March 10, Deperdussin Machine, 31.06 miles; with four passengers, G. +Busson, Rheims, France, March 10, Deperdussin Machine, 15.99 miles. + +Greatest Duration Aviator Alone--G. Fourny, no stops, Buc, France, +September 2, M. Farman Machine, 11 hours, 1 minute, 29 seconds, E. +Helen, three stops, Etampes, France, September 8, Nieuport Machine, 14 +hours, 7 minutes, 50 seconds, 13 hours, 17 minutes net time; with one +passenger, Suvelack, Johannisthal, Germany, December 8, 4 hours, 23 +minutes; with two passengers, T. de W. Milling, Nassau Boulevard, New +York, September 26, Burgess-Wright Machine, 1 hour, 54 minutes, 42 3-5 +seconds; with three passengers, Warchalowski, Wiener-Neustadt, Aust., +October 30, 45 minutes, 46 seconds; with four passengers, G. Busson, +Rheims, France, March 10, Deperdussin Machine, 17 minutes, 28 1-5 +seconds. + +Greatest Altitude Aviator Alone--Garros, St. Malo, France, September +4, Bleriot Machine, 13,362 feet; with one passenger, Prevost, Courcy, +France, December 2, 9,840 feet; with two passengers, Lieut. Bier, +Austria, Etrich Machine, 4,010 feet. + +AMERICAN RECORDS. + +Greatest Speed Per Hour, Whatever Length of Flight, Aviator Alone--A. +Leblanc, Belmont Park, N. Y., October 29, Bleriot Machine, 67.87 miles; +with one passenger, C. Grahame-White, Squantum, Mass., September 4, +Nieuport Machine, 63.23 miles; with two passengers, T. O. M. Sopwith, +Chicago, Ill., August 15, Wright Machine, 34.96 miles. + +Greatest Distance Aviator Alone--St. Croix Johnstone, Mineola, N. Y., +July 27, Moisant (Bleriot Type) Machine, 176.23 miles. + +Greatest Duration Aviator Alone--Howard W. Gill, Kinloch, Mo., October +19, Wright Machine, 4 hours, 16 minutes, 35 seconds; with one passenger, +G. W. Beatty, Chicago, Ill., August 19, Wright Machine, 3 hours, 42 +minutes, 22 1-5 seconds; with two passengers, T. de W. Milling, Nassau +Boulevard, N. Y., September 26, Burgess-Wright Machine, 1 hour, 54 +minutes, 42 3-5 seconds. + +Greatest Altitude Aviator Alone--L. Beachy, Chicago, Ill., August 20, +Curtiss Machine, 11,642 feet; with one passenger, C. Grahame-White, +Nassau Boulevard, N. Y., September 30, Nieuport Machine, 3,347 feet. + +Weight Carrying--P. O. Parmelee, Chicago, III., August 19, Wright +Machine, 458 lbs. + +AVIATION DEVELOPMENT. + +The wonderful progress made in the science of aviation during the +year 1911 far surpasses any twelve months' advancement recorded. The +advancement has not been confined to any country or continent, since +every part of the world is taking its part in aviation history making. + +The rapidly increasing interest in aviation has brought forth schools +for the instruction of flying in both the old and new world, and +licensed air pilots before they receive their sanctions from the +governing aero clubs of their country are required to pass an extremely +trying examination in actual flights. Exhibition flights and races +were common in all parts of the world during 1911, and touring aviators +visited India, China, Japan, South Africa, Australia and South America, +giving exhibitions and instruction. + +Europe was the scene of a number of cross-country races in which entries +ranging from ten to twenty aviators flew from city to city around a +given circuit, which in some instances exceeded 1,000 miles in distance. +Cross-country flights with and without passengers became so common that +those of less than two hours' duration attracted little attention. +There were fewer attempts at high altitude soaring, although the world's +record in this department of aviation was bettered several times. In +place of these high flights, the aviators devoted more attention to +speed, duration and spectacular manoeuvres, which appeared to satisfy +the spectators. The prize money won during 1911 exceeded $1,000,000, but +owing to the increased number of aviators the individual winnings were +not as large as in 1910. + +It is estimated that within the past twelve months more than 300,000 +miles have been covered in aeroplane flights and more than seven +thousand persons, classed either as aviators or passengers, taken up +into the air. The aeroplane of today ranges through monoplane, biplane, +triplane and even quadraplane, and more than two hundred types of these +machines are in use. + +Aeroplanes are becoming a factor of international commerce. The records +of the Bureau of Statistics show that more than $50,000 worth of +aeroplanes were imported into, and exported from, the United States in +the months of July, August and September, 1911. The Bureau of Statistics +only began the maintenance of a separate record of this comparatively +new article of commerce with the opening of the fiscal year 1911-12. + +Two of the prominent developments of 1911 were the introduction of +the hydro-aeroplane and the motorless glider experiments of the +Wright brothers at Killdevil Hills, N. C., where during the two weeks' +experiments numerous flights with and against the wind were made, +culminating in the establishing of a record by Orville Wright on October +25, 1911, when in a 52-mile per hour blow he reached an elevation of 225 +feet and remained in the air 10 minutes and 34 seconds. The search +for the secret of automatic stability still continues, and though some +remarkable progress has been made the solution has not yet been reached. + +NOTABLE CROSS-COUNTRY FLIGHTS OF 1911. + +One of the important features of 1911 in aviation was the rapid increase +in the number and distance of cross-country flights made either for the +purpose of exhibition, testing, instruction or pleasure. Flights between +cities in almost every country of the world became common occurrences. +So great was the number that only those of more than ordinary importance +because of speed, distance or duration are recorded. The flights of +Harry N. Atwood from Boston to Washington and from St. Louis to New +York, and C. P. Rodgers from New York to Los Angeles were the most +important events of the kind in this country. The St Louis to New York +flight was a distance by air route, 1,266 miles. Duration of flight, 12 +days. Net flying time, 28 hours 53 minutes. Average daily flight, 105.5 +miles. Average speed, 43.9 miles per hour. + +Transcontinental Flight of Calbraith P. Rodgers.--All world records +for cross-country flying were broken during the New York to Los Angeles +flight of Calbraith P. Rodgers, who left Sheepshead Bay, N. Y., on +Sunday, September 17, 1911, and completed his flight to the Pacific +Coast on Sunday, November 5, at Pasadena, Cal. Rodgers flew a Wright +biplane, and during his long trip the machine was repeatedly repaired, +so great was the strain of the long journey in the air. Rodgers is +estimated to have covered 4,231 miles, although the actual route as +mapped out was but 4,017 miles. Elapsed time to Pasadena, Cal., 49 days; +actual time in the air, 4,924 minutes, equivalent to 3 days 10 hours 4 +minutes; average speed approximating 51 miles per hour. Rodgers' longest +flight in one day was from Sanderson to Sierra Blanca, Texas, on October +28, when he covered 231 miles. On November 12, Rodgers fell at Compton, +Cal., and was badly injured, causing a delay of 28 days. + +European Circuit Race.--Started from Paris on June 18, 1911. Distance, +1,073 miles, via Paris to Liege; Liege to Spa to Liege; Liege to +Utrecht, Holland; Utrecht to Brussels, Belgium; Brussels to Roubaix; +Roubaix to Calais; Calais to London; London to Calais and Calais to +Paris. Three aeronauts were killed either at the start or shortly after +the race was in progress. They were Capt. Princetau, M. Le Martin and +M. Lendron. Three others were injured by falls. Seven hundred thousand +spectators witnessed the start from the aviation field at Vincennes, +near Paris. There were more than forty starters, of which eight +finished. The winner, Lieut. Jean Conneau, who flies under the name of +"Andre Beaumont," completed the circuit on July 7; his actual net flying +time for the distance being 58h. 38m. 4-5s. + +Circuit of England Race--1,010 Miles in Five Sections.-- + +Start, July 22. Finish, July 26. Prize, $50,000. Twenty-eight entries +and eighteen starters. Seventeen finished the first section from +Brooklands to Hendon, a distance of twenty miles. Five reached +Edinburgh, the second section, a distance of 343 miles, and four +completed the entire circuit. + +Paris to Madrid Race.--This race was started at the Paris aviation +held at Issy-les-Moulineaux on Sunday, May 21. There were twenty-one +entrants, and fully 300,000 spectators gathered to witness the initial +flight of the aerial races. The race was divided into three stages as +follows: Paris to Angouleme, 248 miles; Angouleme to St. Sebastian, 208 +miles, and from St. Sebastian to Madrid, 386 miles, a total distance +of 842 miles. After three of the entrants had safely left the field, +Aviator Train lost control of his plane, and in falling struck and +killed M. Berteaux, the French Minister of War, and seriously injured +Premier Monis. The accident caused the withdrawal of all but six of the +original entrants, and of these but one finished. The race called for +a flight over the Pyrenees Mountains, and Vedrines, the winner, had to +rise to a height of more than 7,000 feet to pass the mountain barrier +near Somosierra Pass. Both Vedrines and Gibert, another competitor, were +attacked by eagles during the latter stages of the flight. Vedrines, +who started from Paris on Monday, May 22, finished the long and perilous +race at 8:06 a. m. Friday, May 26. Vedrines net flying time, all +controls and enforced stops subtracted, was 14h. 55m. 18s. The various +prizes to the winner aggregated $30,000. + +The Paris-Rome-Turin Race.--The conditions of this race called for a +flight between the cities of Paris, Rome and Turin, covering a distance +of 1,300 miles. The aviators were permitted by the rules to alight +whenever and wherever they desired and the time limit was set from +May 28 to June 15. A prize of $100,000 was offered the winner, but the +contest was never finished, as one after another the aviators dropped +out until Frey fell near Roncigilione, France, breaking both arms and +legs and unofficially ending the contest. There were twenty-one entries +and twelve actual starters. + +International Speed Cup Race.--The third annual international James +Gordon Bennett speed cup race was held at Eastchurch, England, on July +1, 1911, and for the second time was won by an American aviator, C. T. +Weymann, in a French racing aeroplane. The distance was 150 kilometres +equivalent to 94 miles, and the winner's time of 1h. 11m. 36s. showed an +average speed of 78.77 miles per hour. The first race was held in 1909 +and was won by Glenn Curtiss, who flew the twenty kilometres (12.4 +miles) in 15 minutes 50 2-5 seconds at an average speed of 47 miles per +hour. In 1910 the winner was Grahame-White, who covered 100 kilometres +(62 miles) at Belmont Park, L. I., in 60 minutes 47 3-5 seconds, an +average speed of 61.3 miles per hour. In the 1911 race there were six +starters: three from France, two from Great Britain and one from the +United States. + +Milan to Turin to Milan Race.--This race which was started from Milan, +Italy, on October 29, was restricted to Italian aviators and had six +starters. The distance was approximately 177 miles and won by Manissero +in a Bleriot machine in 3h. 16m. 2 4-5s. + +New York to Philadelphia Race.--The first intercity aeroplane race ever +held in the United States was started from New York City on August +5, and finished in Philadelphia the same day. The prize of $5,000 was +offered by a commercial concern with stores in the two cities: Three +entrants competed from the Curtiss Exhibition Company. The distance was +approximately 83 miles and won by L. Beachey in a Curtiss machine in 1h. +50m. at an average speed of 45 miles per hour. + +Tri-State Race.--The tri-state race was the feature event of the Harvard +Aviation Society meet held at Squantum, Mass., August 26 to September +6. It was held Labor Day, September 4, over a course of 174 miles, from +Boston to Nashua to Worcester to Providence to Boston. Four competitors +started, of which two finished, the winner, E. Ovington, in a Bleriot +machine. Ovington's net flying time, 3h. 6m. 22 1-5s. Winner's prize, +$10,000. + +AEROPLANES AND DIRIGIBLE BALLOONS IN WARFARE. + +Wonderful progress has been made in the development of the aeroplane in +this country and in Europe since 1903, and within the last two or three +years the leading powers of the world have entered upon extensive tests +and experiments to determine its availability and usefulness in land and +naval warfare. + +At the present time all the great powers are building or purchasing +aeroplanes on an extensive scale. They have established government +schools for the instruction of their army and navy officers and for +experimental work. So-called "Airship Fleets" have been constructed and +placed in commission as auxiliaries to the armies and navies. The fleets +of France and Germany are about equal and are larger by far than those +of any of the other powers. The length of the dirigibles composing these +fleets runs from 150 to 500 feet; they are equipped with engines of from +50 to 500 horse-power, with a rate of speed ranging from 20 to 30 miles +per hour. Their approximate range is from 200 to 900 miles; the longest +actual run (made by the Zeppelin II, Germany) is 800 miles. + +A British naval airship, one of the largest yet built, was completed +last summer. It has cost over $200,000, and it was in course of +designing and construction two years. It is 510 feet long; can carry 22 +persons, and has a lift of 21 tons. + +The relative value of the dirigible balloon and the aeroplane in actual +war is yet to be determined. The dirigible is considered to be the +safer, yet several large balloons of this class in Germany and France +have met with disaster, involving loss of lives. The capacity of the +dirigible for longer flights and its superior facilities for carrying +apparatus and operators for wireless telegraphy are distinct advantages. + +There has not yet been much opportunity to test the airship in actual +warfare. The aeroplane has been used by the Italians in Tripoli for +scouting and reconnoitering and is said to have justified expectations. +On several occasions the Italian military aviators followed the +movements of the enemy, in one instance as far as forty miles inland. At +the time of the attack by the Turks a skillful aeroplane reconnaissance +revealed the approach of a large Turkish force, believed to be at the +time sixty miles away in the mountains. + +Aeroplanes and airships, as they exist today, would doubtless render +very valuable service in a time of war, both over land and water, in +scouting, reconnoitering, carrying dispatches, and as some experts +believe, in locating submarines and mines placed by the enemy in +channels of exits from ports. A "coast aeroplane" could fly out 30 or 40 +miles from land, and rising to a great height, descry any hostile ships +on the distant horizon, observe their number, strength, formation and +direction, and return within two hours with a report to obtain which +would require several swift torpedo-boat destroyers and a much greater +time. The question as to whether it would be practicable to bombard an +enemy on land or sea with explosive bombs dropped or discharged from +flying machines or airships, is one which is much discussed but hardly +yet determined. + +Aeroplanes have been constructed with floats in the place of runners and +several attempts have been made, in some cases successfully, to light +with them on and to rise from the water. Mr. Curtiss did this at San +Francisco, in January, 1911. Attempts have also been made with the +aeroplane to alight on and to take flight from the deck of a warship. +Toward the end of 1910 Aviator Ely flew to land from the cruiser +Birmingham, and in January, 1911, he flew from land and alighted on the +cruiser Pennsylvania. But in these cases special arrangements were made +which would be hardly practicable in a time of actual war. + +In November, 1911, a test was made at Newport, R. I., by Lieut. Rodgers, +of the navy, of a "hydro-areoplane" as an auxiliary to a battleship. The +idea of the test was to alight alongside of the ship, hoist the machine +aboard, put out to sea and launch the machine again with the use of a +crane. Lieut. Rodgers came down smoothly alongside the Ohio, his machine +was easily drawn aboard with a crane, and the Ohio steamed down to +the open sea, where it was blowing half a gale. But, owing to the +misjudgment of the ship's headway, one of the wings of the machine when +it struck the water after being released from the crane, went under the +water and was snapped off. Lieut. Rodgers was convinced that this method +was too risky and that some other must be devised. + + + +CHAPTER XXVIII. GLOSSARY OF AERONAUTICAL TERMS. + +Aerodrome.--Literally a machine that runs in the air. Aerofoil.--The +advancing transverse section of an aeroplane. + +Aeroplane.--A flying machine of the glider pattern, used in +contra-distinction to a dirigible balloon. + +Aeronaut.--A person who travels in the air. + +Aerostat.--A machine sustaining weight in the air. A balloon is an +aerostat. + +Aerostatic.--Pertaining to suspension in the air; the art of aerial +navigation. + +Ailerons.--Small stabilizing planes attached to the main planes to +assist in preserving equilibrium. + +Angle of Incidence.--Angle formed by making comparison with a +perpendicular line or body. + +Angle of Inclination.--Angle at which a flying machine rises. This +angle, like that of incidence, is obtained by comparison with an +upright, or perpendicular line. + +Auxiliary Planes.--Minor plane surfaces, used in conjunction with the +main planes for stabilizing purposes. + +Biplane.--A flying-machine of the glider type with two surface planes. + +Blade Twist.--The angle of twist or curvature on a propeller blade. + +Cambered.--Curve or arch in plane, or wing from port to starboard. + +Chassis.--The under framework of a flying machine; the framework of the +lower plane. + +Control.--System by which the rudders and stabilizing planes are +manipulated. + +Dihedral.--Having two sides and set at an angle, like dihedral planes, +or dihedral propeller blades. + +Dirigible.--Obedient to a rudder; something that may be steered or +directed. + +Helicopter.--Flying machine the lifting power of which is furnished by +vertical propellers. + +Lateral Curvature.--Parabolic form in a transverse direction. + +Lateral Equilibrium or Stability.--Maintenance of the machine on an even +keel transversely. If the lateral equilibrium is perfect the extreme +ends of the machine will be on a dead level. + +Longitudinal Equilibrium or Stability.--Maintenance of the machine on an +even keel from front to rear. + +Monoplane.--Flying machine with one supporting, or surface plane. + +Multiplane.--Flying machine with more than three surface planes. + +Ornithopter.--Flying machine with movable bird-like wings. + +Parabolic Curves.--Having the form of a parabola--a conic section. + +Pitch of Propeller Blade.--See "Twist." + +Ribs.--The pieces over which the cloth covering is stretched. + +Spread.--The distance from end to end of the main surface; the +transverse dimension. + +Stanchions.--Upright pieces connecting the upper and lower frames. + +Struts.--The pieces which hold together longitudinally the main frame +beams. + +Superposed.--Placed one over another. + +Surface Area.--The amount of cloth-covered supporting surface which +furnishes the sustaining quality. + +Sustentation.--Suspension in the air. Power of sustentation; the quality +of sustaining a weight in the air. + +Triplane.--Flying machine with three surface planes. + +Thrust of Propeller.--Power with which the blades displace the air. + +Width.--The distance from the front to the rear edge of a flying +machine. + +Wind Pressure.--The force exerted by the wind when a body is moving +against it. There is always more or less wind pressure, even in a calm. + +Wing Tips.--The extreme ends of the main surface planes. Sometimes these +are movable parts of the main planes, and sometimes separate auxiliary +planes. + + + + +Footnotes: + +[Footnote 1: Now dead.] + +[Footnote 2: Aeronautics.] + +[Footnote 3: See Chapter XXV.] + +[Footnote 4: The Wrights' new machine weighs only 900 pounds.] + +[Footnote 5: Aeronautics.] + + + + + + +End of the Project Gutenberg EBook of Flying Machines, by +W.J. Jackman and Thos. H. 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Russell + + + +FLYING MACHINES: CONSTRUCTION and OPERATION + + + +A Practical Book Which Shows, in Illustrations, +Working Plans and Text, How to Build and Navigate the +Modern Airship. + +By +W.J. Jackman, M.E., +Author of "A B C of the Motorcycle," +"Facts for Motorists," etc. etc. + +AND + +THOS. H. RUSSELL, A.M., M.E., +Charter Member of the Aero Club of Illinois, Author of +"History of the Automobile," "Motor Boats: Construction +and Operation," etc. etc. + +WITH INTRODUCTORY CHAPTER BY +OCTAVE CHANUTE, C.E., +President Aero Club of Illinois + +1912 + + + +PREFACE. + +This book is written for the guidance of the novice in +aviation--the man who seeks practical information as to +the theory, construction and operation of the modern +flying machine. With this object in view the wording +is intentionally plain and non-technical. It contains some +propositions which, so far as satisfying the experts is +concerned, might doubtless be better stated in technical +terms, but this would defeat the main purpose of its preparation. +Consequently, while fully aware of its shortcomings +in this respect, the authors have no apologies to make. + +In the stating of a technical proposition so it may be +clearly understood by people not versed in technical matters +it becomes absolutely necessary to use language +much different from that which an expert would employ, +and this has been done in this volume. + +No man of ordinary intelligence can read this book +without obtaining a clear, comprehensive knowledge of +flying machine construction and operation. He will +learn, not only how to build, equip, and manipulate an +aeroplane in actual flight, but will also gain a thorough +understanding of the principle upon which the suspension +in the air of an object much heavier than the air is made +possible. + +This latter feature should make the book of interest +even to those who have no intention of constructing or +operating a flying machine. It will enable them to better +understand and appreciate the performances of the +daring men like the Wright brothers, Curtiss, Bleriot, +Farman, Paulhan, Latham, and others, whose bold experiments +have made aviation an actuality. + +For those who wish to engage in the fascinating pastime +of construction and operation it is intended as a +reliable, practical guide. + +It may be well to explain that the sub-headings in the +articles by Mr. Chanute were inserted by the authors +without his knowledge. The purpose of this was merely +to preserve uniformity in the typography of the book. +This explanation is made in justice to Mr. Chanute. + THE AUTHORS. + + + +IN MEMORIAM. + +Octave Chanute, "the father of the modern flying machine," +died at his home in Chicago on November 23, 1910, +at the age of 72 years. His last work in the interest of +aviation was to furnish the introductory chapter to the first +edition of this volume, and to render valuable assistance +in the handling of the various subjects. He even made the +trip from his home to the office of the publishers one +inclement day last spring, to look over the proofs of the +book and, at his suggestion, several important changes were +made. All this was "a labor of love" on Mr. Chanute's +part. He gave of his time and talents freely because he +was enthusiastic in the cause of aviation, and because he +knew the authors of this book and desired to give them +material aid in the preparation of the work--a favor that +was most sincerely appreciated. + + +The authors desire to make acknowledgment of many courtesies +in the way of valuable advice, information, etc., extended by Mr. +Octave Chanute, C. E., Mr. E. L. Jones, Editor of Aeronautics, +and the publishers of, the New England Automobile Journal and +Fly. + + + +CONTENTS + +Chapter + +I. Evolution of the Two-Surface Flying Machine + Introductory Chapter by Octave Chanute, C. E. +II. Theory Development and Use + Origin of the Aeroplane--Developments by Chanute + and the Wrights--Practical Uses and Limits. +III. Mechanical Bird Action + What the Motor Does--Puzzle in Bird Soaring. +IV. Various Forms of Flying Machines + Helicopters, Ornithopters and Aeroplanes-- + Monoplanes, Biplanes and Triplanes. +V. Constructing a Gliding Machine + Plans and Materials Required--Estimate of Cost-- + Sizes and Preparation of Various Parts--Putting the + Parts Together +VI. Learning to Fly + How to Use the Glider--Effect of Body Movements + --Rules for Beginners--Safest Place to Glide. +VII. Putting On the Rudder + Its Construction, Application and Use. +VIII. The Real Flying Machine + Surface Area Required--Proper Size of Frame and + Auxiliaries--Installation of Motor--Cost of + Constructing Machine. +IX. Selection of the Motor + Essential Features--Multiplicity of Cylinders--Power + Required--Kind and Action of Propellers--Placing + of the Motor +X. Proper Dimensions of Machines + Figuring Out the Details--How to Estimate Load + Capacity--Distribution of the Weight--Measurements + of Leading Machines. +XI. Plane and Rudder Control + Various Methods in Use--Wheels and Hand and + Foot Levers +XII. How to Use the Machine + Rules of Leading Aviators--Rising from the Ground + --Reasonable Altitude--Preserving Equilibrium-- + Learning to Steer. +XIII. Peculiarities of Aeroplane Power + Pressure of the Wind--How to Determine Upon + Power--Why Speed Is Required--Bird find Flying + Machine Areas. +XIV. About Wind Currents, Etc. + Uncertainty of Direct Force--Trouble With Gusty + Currents--Why Bird Action Is Imitated. +XV. The Element of Danger + Risk Small Under Proper Conditions--Two Fields + of Safety--Lessons in Recent Accidents. +XVI. Radical Changes Being Made + Results of Recent Experiments--New Dimensions + --Increased Speed--The One Governing Rule. +XVII. Some of the New Designs + ù Automatic Control of Plane Stability--Inventor + Herring's Devices--Novel Ideas of Students. +XVIII. Demand for Flying Machines + Wonderful Results in a Year--Factories Over- + crowded with Orders. +XIX. Law of the Airship + Rights of Property Owners--Some Legal + Peculiarities--Danger of Trespass. +XX. Soaring Flight +XXI. Flying Machines vs. Balloons +XXII. Problems of Aerial Fligh +XXIII. Amateurs May Use Wright Patents +XXIV. Hints on Propeller Construction +XXV. New Motors and Devices +XXVI. Monoplanes, Triplanes, Multiplanes +XXVII. Records of Various Kinds + + + + +FLYING MACHINES: CONSTRUCTION and OPERATION + + + +CHAPTER I. + +EVOLUTION OF TWO-SURFACE FLYING MACHINE. + +By Octave Chanute. + + +I am asked to set forth the development of the "two- +surface" type of flying machine which is now used with +modifications by Wright Brothers, Farman, [1]Delagrange, +Herring and others. + + +[1] Now dead. + + +This type originated with Mr. F. H. Wenham, who +patented it in England in 1866 (No. 1571), taking out +provisional papers only. In the abridgment of British +patent Aeronautical Specifications (1893) it is described +as follows: + +"Two or more aeroplanes are arranged one above the +other, and support a framework or car containing the +motive power. The aeroplanes are made of silk or canvas +stretched on a frame by wooden rods or steel ribs. +When manual power is employed the body is placed +horizontally, and oars or propellers are actuated by the +arms or legs. + +"A start may be obtained by lowering the legs and +running down hill or the machine may be started from +a moving carriage. One or more screw propellers may +be applied for propelling when steam power is employed. + +On June 27, 1866, Mr. Wenham read before the +"Aeronautical Society of Great Britain," then recently +organized, the ablest paper ever presented to that society, and +thereby breathed into it a spirit which has continued to +this day. In this paper he described his observations of +birds, discussed the laws governing flight as to the +surfaces and power required both with wings and screws, +and he then gave an account of his own experiments with +models and with aeroplanes of sufficient size to carry +the weight of a man. + +Second Wenham Aeroplane. + +His second aeroplane was sixteen feet from tip to tip. +A trussed spar at the bottom carried six superposed +bands of thin holland fabric fifteen inches wide, connected +with vertical webs of holland two feet apart, thus +virtually giving a length of wing of ninety-six feet and +one hundred and twenty square feet of supporting surface. +The man was placed horizontally on a base board +beneath the spar. This apparatus when tried in the wind +was found to be unmanageable by reason of the fluttering +motions of the fabric, which was insufficiently stiffened +with crinoline steel, but Mr. Wenham pointed out that +this in no way invalidated the principle of the apparatus, +which was to obtain large supporting surfaces without +increasing unduly the leverage and consequent weight +of spar required, by simply superposing the surfaces. + +This principle is entirely sound and it is surprising that +it is, to this day, not realized by those aviators who are +hankering for monoplanes. + +Experiments by Stringfellow. + +The next man to test an apparatus with superposed +surfaces was Mr. Stringfellow, who, becoming much impressed +with Mr. Wenham's proposal, produced a largish +model at the exhibition of the Aeronautical Society in +1868. It consisted of three superposed surfaces aggregating 28 +square feet and a tail of 8 square feet more. +The weight was under 12 pounds and it was driven by a +central propeller actuated by a steam engine overestimated +at one-third of a horsepower. It ran suspended +to a wire on its trials but failed of free flight, in +consequence of defective equilibrium. This apparatus has +since been rebuilt and is now in the National Museum +of the Smithsonian Institution at Washington. +Linfield's Unsuccessful Efforts. + +In 1878 Mr. Linfield tested an apparatus in England +consisting of a cigar-shaped car, to which was attached +on each side frames five feet square, containing each +twenty-five superposed planes of stretched and varnished +linen eighteen inches wide, and only two inches apart, +thus reminding one of a Spanish donkey with panniers. +The whole weighed two hundred and forty pounds. This +was tested by being mounted on a flat car behind a +locomotive going 40 miles an hour. When towed by a line +fifteen feet long the apparatus rose only a little from the +car and exhibited such unstable equilibrium that the +experiment was not renewed. The lift was only about one- +third of what it would have been had the planes been +properly spaced, say their full width apart, instead of +one-ninth as erroneously devised. + +Renard's "Dirigible Parachute." + +In 1889 Commandant Renard, the eminent superintendent +of the French Aeronautical Department, exhibited +at the Paris Exposition of that year, an apparatus +experimented with some years before, which he termed +a "dirigible parachute." It consisted of an oviform body +to which were pivoted two upright slats carrying above +the body nine long superposed flat blades spaced about +one-third of their width apart. When this apparatus +was properly set at an angle to the longitudinal axis of +the body and dropped from a balloon, it travelled back +against the wind for a considerable distance before +alighting. The course could be varied by a rudder. No +practical application seems to have been made of this +device by the French War Department, but Mr. J. P. +Holland, the inventor of the submarine boat which bears +his name, proposed in 1893 an arrangement of pivoted +framework attached to the body of a flying machine +which combines the principle of Commandant Renard +with the curved blades experimented with by Mr. Phillips, +now to be noticed, with the addition of lifting screws +inserted among the blades. + +Phillips Fails on Stability Problem. + +In 1893 Mr. Horatio Phillips, of England, after some +very interesting experiments with various wing sections, +from which he deduced conclusions as to the shape of +maximum lift, tested an apparatus resembling a Venetian +blind which consisted of fifty wooden slats of +peculiar shape, 22 feet long, one and a half inches wide, +and two inches apart, set in ten vertical upright boards. +All this was carried upon a body provided with three +wheels. It weighed 420 pounds and was driven at 40 +miles an hour on a wooden sidewalk by a steam engine +of nine horsepower which actuated a two-bladed screw. +The lift was satisfactory, being perhaps 70 pounds per +horsepower, but the equilibrium was quite bad and the +experiments were discontinued. They were taken up +again in 1904 with a similar apparatus large enough to +carry a passenger, but the longitudinal equilibrium was +found to be defective. Then in 1907 a new machine was +tested, in which four sets of frames, carrying similar sets +of slat "sustainers" were inserted, and with this +arrangement the longitudinal stability was found to be very +satisfactory. The whole apparatus, with the operator, +weighed 650 pounds. It flew about 200 yards when +driven by a motor of 20 to 22 h.p. at 30 miles an hour, +thus exhibiting a lift of about 32 pounds per h.p., while +it will be remembered that the aeroplane of Wright +Brothers exhibits a lifting capacity of 50 pounds to +the h.p. + +Hargrave's Kite Experiments. + +After experimenting with very many models and +building no less than eighteen monoplane flying model +machines, actuated by rubber, by compressed air and by +steam, Mr. Lawrence Hargrave, of Sydney, New South +Wales, invented the cellular kite which bears his name +and made it known in a paper contributed to the Chicago +Conference on Aerial Navigation in 1893, describing +several varieties. The modern construction is well +known, and consists of two cells, each of superposed surfaces +with vertical side fins, placed one behind the other +and connected by a rod or frame. This flies with great +steadiness without a tail. Mr. Hargrave's idea was to +use a team of these kites, below which he proposed to +suspend a motor and propeller from which a line would +be carried to an anchor in the ground. Then by actuating +the propeller the whole apparatus would move +forward, pick up the anchor and fly away. He said: +"The next step is clear enough, namely, that a flying +machine with acres of surface can be safely got under +way or anchored and hauled to the ground by means of +the string of kites." + +The first tentative experiments did not result well and +emphasized the necessity for a light motor, so that Mr. +Hargrave has since been engaged in developing one, not +having convenient access to those which have been produced +by the automobile designers and builders. + +Experiments With Glider Model. + +And here a curious reminiscence may be indulged in. +In 1888 the present writer experimented with a two-cell +gliding model, precisely similar to a Hargrave kite, as +will be confirmed by Mr. Herring. It was frequently +tested by launching from the top of a three-story house +and glided downward very steadily in all sorts of breezes, +but the angle of descent was much steeper than that of +birds, and the weight sustained per square foot was less +than with single cells, in consequence of the lesser support +afforded by the rear cell, which operated upon air +already set in motion downward by the front cell, so +nothing more was done with it, for it never occurred to +the writer to try it as a kite and he thus missed the +distinction which attaches to Hargrave's name. + +Sir Hiram Maxim also introduced fore and aft superposed +surfaces in his wondrous flying machine of 1893, +but he relied chiefly for the lift upon his main large surface +and this necessitated so many guys, to prevent distortion, +as greatly to increase the head resistance and +this, together with the unstable equilibrium, made it +evident that the design of the machine would have to +be changed. + +How Lilienthal Was Killed. + +In 1895, Otto Lilienthal, the father of modern aviation, +the man to whose method of experimenting almost all +present successes are due, after making something like +two thousand glides with monoplanes, added a superposed +surface to his apparatus and found the control of +it much improved. The two surfaces were kept apart +by two struts or vertical posts with a few guy wires, but +the connecting joints were weak and there was nothing +like trussing. This eventually cost his most useful life. +Two weeks before that distressing loss to science, Herr +Wilhelm Kress, the distinguished and veteran aviator +of Vienna, witnessed a number of glides by Lilienthal +with his double-decked apparatus. He noticed that it +was much wracked and wobbly and wrote to me after +the accident: "The connection of the wings and the +steering arrangement were very bad and unreliable. I +warned Herr Lilienthal very seriously. He promised +me that he would soon put it in order, but I fear that he +did not attend to it immediately." + +In point of fact, Lilienthal had built a new machine, +upon a different principle, from which he expected great +results, and intended to make but very few more flights +with the old apparatus. He unwisely made one too +many and, like Pilcher, was the victim of a distorted +apparatus. Probably one of the joints of the struts +gave way, the upper surface blew back and Lilienthal, +who was well forward on the lower surface, was pitched +headlong to destruction. + +Experiments by the Writer. + +In 1896, assisted by Mr. Herring and Mr. Avery, I +experimented with several full sized gliding machines, +carrying a man. The first was a Lilienthal monoplane +which was deemed so cranky that it was discarded after +making about one hundred glides, six weeks before +Lilienthal's accident. The second was known as the +multiple winged machine and finally developed into five +pairs of pivoted wings, trussed together at the front and +one pair in the rear. It glided at angles of descent of +10 or 11 degrees or of one in five, and this was deemed +too steep. Then Mr. Herring and myself made computations +to analyze the resistances. We attributed much +of them to the five front spars of the wings and on a +sheet of cross-barred paper I at once drew the design for +a new three-decked machine to be built by Mr. Herring. + +Being a builder of bridges, I trussed these surfaces +together, in order to obtain strength and stiffness. When +tested in gliding flight the lower surface was found too +near the ground. It was taken off and the remaining +apparatus now consisted of two surfaces connected together +by a girder composed of vertical posts and diagonal +ties, specifically known as a "Pratt truss." Then +Mr. Herring and Mr. Avery together devised and put +on an elastic attachment to the tail. This machine +proved a success, it being safe and manageable. Over +700 glides were made with it at angles of descent of 8 +to 10 degrees, or one in six to one in seven. + +First Proposed by Wenham. + +The elastic tail attachment and the trussing of the +connecting frame of the superposed wings were the only +novelties in this machine, for the superposing of the +surfaces had first been proposed by Wenham, but in +accordance with the popular perception, which bestows +all the credit upon the man who adds the last touch +making for success to the labors of his predecessors, the +machine has since been known by many persons as the +"Chanute type" of gliders, much to my personal gratification. + +It has since been improved in many ways. Wright +Brothers, disregarding the fashion which prevails among +birds, have placed the tail in front of their apparatus and +called it a front rudder, besides placing the operator in +horizontal position instead of upright, as I did; and also +providing a method of warping the wings to preserve +equilibrium. Farman and Delagrange, under the very +able guidance and constructive work of Voisin brothers, +then substituted many details, including a box tail for +the dart-like tail which I used. This may have increased +the resistance, but it adds to the steadiness. Now the +tendency in France seems to be to go back to the monoplane. + +Monoplane Idea Wrong. + +The advocates of the single supporting surface are +probably mistaken. It is true that a single surface +shows a greater lift per square foot than superposed +surfaces for a given speed, but the increased weight due +to leverage more than counterbalances this advantage by +requiring heavy spars and some guys. I believe that +the future aeroplane dynamic flier will consist of superposed +surfaces, and, now that it has been found that by +imbedding suitably shaped spars in the cloth the head +resistance may be much diminished, I see few objections +to superposing three, four or even five surfaces properly +trussed, and thus obtaining a compact, handy, manageable +and comparatively light apparatus.[2] + + +[2] Aeronautics. + + + +CHAPTER II. + +THEORY, DEVELOPMENT, AND USE. + + +While every craft that navigates the air is an airship, +all airships are not flying machines. The balloon, +for instance, is an airship, but it is not what is known +among aviators as a flying machine. This latter term +is properly used only in referring to heavier-than-air +machines which have no gas-bag lifting devices, and are made to +really fly by the application of engine propulsion. + +Mechanical Birds. + +All successful flying machines--and there are a number +of them--are based on bird action. The various +designers have studied bird flight and soaring, mastered +its technique as devised by Nature, and the modern flying +machine is the result. On an exaggerated, enlarged +scale the machines which are now navigating the air +are nothing more nor less than mechanical birds. + +Origin of the Aeroplane. + +Octave Chanute, of Chicago, may well be called "the +developer of the flying machine." Leaving balloons and +various forms of gas-bags out of consideration, other +experimenters, notably Langley and Lilienthal, antedated +him in attempting the navigation of the air on +aeroplanes, or flying machines, but none of them were +wholly successful, and it remained for Chanute to demonstrate +the practicability of what was then called the +gliding machine. This term was adopted because the +apparatus was, as the name implies, simply a gliding +machine, being without motor propulsion, and intended +solely to solve the problem of the best form of +construction. The biplane, used by Chanute in 1896, is +still the basis of most successful flying machines, the +only radical difference being that motors, rudders, etc., +have been added. + +Character of Chanute's Experiments. + +It was the privilege of the author of this book to be +Mr. Chanute's guest at Millers, Indiana, in 1896, when, +in collaboration with Messrs. Herring and Avery, he was +conducting the series of experiments which have since +made possible the construction of the modern flying +machine which such successful aviators as the Wright +brothers and others are now using. It was a wild +country, much frequented by eagles, hawks, and similar +birds. The enthusiastic trio, Chanute, Herring and +Avery, would watch for hours the evolutions of some +big bird in the air, agreeing in the end on the verdict, +"When we master the principle of that bird's soaring +without wing action, we will have come close to solving +the problem of the flying machine." + +Aeroplanes of various forms were constructed by Mr. +Chanute with the assistance of Messrs. Herring and +Avery until, at the time of the writer's visit, they had +settled upon the biplane, or two-surface machine. Mr. +Herring later equipped this with a rudder, and made +other additions, but the general idea is still the basis of +the Wright, Curtiss, and other machines in which, by +the aid of gasolene motors, long flights have been made. + +Developments by the Wrights. + +In 1900 the Wright brothers, William and Orville, who were then +in the bicycle business in Dayton, Ohio, +became interested in Chanute's experiments and +communicated with him. The result was that the Wrights +took up Chanute's ideas and developed them further, +making many additions of their own, one of which was +the placing of a rudder in front, and the location of the +operator horizontally on the machine, thus diminishing +by four-fifths the wind resistance of the man's body. +For three years the Wrights experimented with the +glider before venturing to add a motor, which was not +done until they had thoroughly mastered the control of +their movements in the air. + +Limits of the Flying Machine. + +In the opinion of competent experts it is idle to look +for a commercial future for the flying machine. There +is, and always will be, a limit to its carrying capacity +which will prohibit its employment for passenger or +freight purposes in a wholesale or general way. There +are some, of course, who will argue that because a +machine will carry two people another may be constructed +that will carry a dozen, but those who make +this contention do not understand the theory of weight +sustentation in the air; or that the greater the load the +greater must be the lifting power (motors and plane +surface), and that there is a limit to these--as will be +explained later on--beyond which the aviator cannot go. + +Some Practical Uses. + +At the same time there are fields in which the flying +machine may be used to great advantage. These are: + +Sports--Flying machine races or flights will always +be popular by reason of the element of danger. It is +a strange, but nevertheless a true proposition, that it is +this element which adds zest to all sporting events. + +Scientific--For exploration of otherwise inaccessible +regions such as deserts, mountain tops, etc. + +Reconnoitering--In time of war flying machines may +be used to advantage to spy out an enemy's encampment, +ascertain its defenses, etc. + + + +CHAPTER III. + +MECHANICAL BIRD ACTION + +In order to understand the theory of the modern flying +machine one must also understand bird action and wind +action. In this connection the following simple experiment +will be of interest: + +Take a circular-shaped bit of cardboard, like the lid of +a hat box, and remove the bent-over portion so as to +have a perfectly flat surface with a clean, sharp edge. +Holding the cardboard at arm's length, withdraw your +hand, leaving the cardboard without support. What is +the result? The cardboard, being heavier than air, and +having nothing to sustain it, will fall to the ground. +Pick it up and throw it, with considerable force, against +the wind edgewise. What happens? Instead of falling +to the ground, the cardboard sails along on the wind, +remaining afloat so long as it is in motion. It seeks +the ground, by gravity, only as the motion ceases, and +then by easy stages, instead of dropping abruptly as in +the first instance. + +Here we have a homely, but accurate illustration of +the action of the flying machine. The motor does for +the latter what the force of your arm does for the cardboard-- +imparts a motion which keeps it afloat. The +only real difference is that the motion given by the +motor is continuous and much more powerful than that +given by your arm. The action of the latter is limited +and the end of its propulsive force is reached within a +second or two after it is exerted, while the action of the +motor is prolonged. + +Another Simple Illustration. + +Another simple means of illustrating the principle of +flying machine operation, so far as sustentation and the +elevation and depression of the planes is concerned, is +explained in the accompanying diagram. + +A is a piece of cardboard about 2 by 3 inches in size. +B is a piece of paper of the same size pasted to one edge +of A. If you bend the paper to a curve, with convex +side up and blow across it as shown in Figure C, the +paper will rise instead of being depressed. The dotted +lines show that the air is passing over the top of the +curved paper and yet, no matter how hard you may +blow, the effect will be to elevate the paper, despite the +fact that the air is passing over, instead of under the +curved surface. + +In Figure D we have an opposite effect. Here the +paper is in a curve exactly the reverse of that shown in +Figure C, bringing the concave side up. Now if you +will again blow across the surface of the card the action +of the paper will be downward--it will be impossible to +make it rise. The harder you blow the greater will be +the downward movement. + +Principle In General Use. + +This principle is taken advantage of in the construction +of all successful flying machines. Makers of monoplanes +and biplanes alike adhere to curved bodies, with +the concave surface facing downward. Straight planes +were tried for a time, but found greatly lacking in the +power of sustentation. By curving the planes, and placing +the concave surface downward, a sort of inverted bowl +is formed in which the air gathers and exerts a buoyant +effect. Just what the ratio of the curve should be is a +matter of contention. In some instances one inch to the +foot is found to be satisfactory; in others this is doubled, +and there are a few cases in which a curve of as much as +3 inches to the foot has been used. + +Right here it might be well to explain that the word +"plane" applied to flying machines of modern construction +is in reality a misnomer. Plane indicates a flat, +level surface. As most successful flying machines have +curved supporting surfaces it is clearly wrong to speak +of "planes," or "aeroplanes." Usage, however, has made +the terms convenient and, as they are generally accepted +and understood by the public, they are used in like manner +in this volume. + +Getting Under Headway. + +A bird, on first rising from the ground, or beginning +its flight from a tree, will flap its wings to get under +headway. Here again we have another illustration of +the manner in which a flying machine gets under headway-- +the motor imparts the force necessary to put the +machine into the air, but right here the similarity ceases. +If the machine is to be kept afloat the motor must be +kept moving. A flying machine will not sustain itself; +it will not remain suspended in the air unless it is +under headway. This is because it is heavier than air, +and gravity draws it to the ground. + +Puzzle in Bird Soaring. + +But a bird, which is also heavier than air, will remain +suspended, in a calm, will even soar and move in a +circle, without apparent movement of its wings. This +is explained on the theory that there are generally vertical +columns of air in circulation strong enough to sustain +a bird, but much too weak to exert any lifting power +on a flying machine, It is easy to understand how a +bird can remain suspended when the wind is in action, +but its suspension in a seeming dead calm was a puzzle +to scientists until Mr. Chanute advanced the proposition +of vertical columns of air. + +Modeled Closely After Birds. + +So far as possible, builders of flying machines have +taken what may be called "the architecture" of birds as +a model. This is readily noticeable in the form of +construction. When a bird is in motion its wings (except +when flapping) are extended in a straight line at right +angles to its body. This brings a sharp, thin edge +against the air, offering the least possible surface for +resistance, while at the same time a broad surface for +support is afforded by the flat, under side of the wings. +Identically the same thing is done in the construction of +the flying machine. + +Note, for instance, the marked similarity in form as +shown in the illustration in Chapter II. Here A is the +bird, and B the general outline of the machine. The +thin edge of the plane in the latter is almost a duplicate +of that formed by the outstretched wings of the bird, +while the rudder plane in the rear serves the same purpose +as the bird's tail. + + + +CHAPTER IV. + +VARIOUS FORMS OF FLYING MACHINES. + +There are three distinct and radically different forms +of flying machines. These are: + +Aeroplanes, helicopters and ornithopers. + +Of these the aeroplane takes precedence and is used +almost exclusively by successful aviators, the helicopters +and ornithopers having been tried and found lacking in +some vital features, while at the same time in some +respects the helicopter has advantages not found in the +aeroplane. + +What the Helicopter Is. + +The helicopter gets its name from being fitted with +vertical propellers or helices (see illustration) by the +action of which the machine is raised directly from the +ground into the air. This does away with the necessity +for getting the machine under a gliding headway before +it floats, as is the case with the aeroplane, and consequently +the helicopter can be handled in a much smaller +space than is required for an aeroplane. This, in many +instances, is an important advantage, but it is the only +one the helicopter possesses, and is more than overcome +by its drawbacks. The most serious of these is that the +helicopter is deficient in sustaining capacity, and requires +too much motive power. + +Form of the Ornithopter. + +The ornithopter has hinged planes which work like +the wings of a bird. At first thought this would seem +to be the correct principle, and most of the early experimenters +conducted their operations on this line. It +is now generally understood, however, that the bird in +soaring is in reality an aeroplane, its extended wings +serving to sustain, as well as propel, the body. At any +rate the ornithoper has not been successful in aviation, +and has been interesting mainly as an ingenious toy. +Attempts to construct it on a scale that would permit +of its use by man in actual aerial flights have been far +from encouraging. + +Three Kinds of Aeroplanes. + +There are three forms of aeroplanes, with all of which +more or less success has been attained. These are: + +The monoplane, a one-surfaced plane, like that used +by Bleriot. + +The biplane, a two-surfaced plane, now used by the +Wrights, Curtiss, Farman, and others. + +The triplane, a three-surfaced plane This form is +but little used, its only prominent advocate at present +being Elle Lavimer, a Danish experimenter, who has not +thus far accomplished much. + +Whatever of real success has been accomplished in +aviation may be credited to the monoplane and biplane, +with the balance in favor of the latter. The monoplane +is the more simple in construction and, where weight- +sustaining capacity is not a prime requisite, may +probably be found the most convenient. This opinion is +based on the fact that the smaller the surface of the +plane the less will be the resistance offered to the air, +and the greater will be the speed at which the machine +may be moved. On the other hand, the biplane has a +much greater plane surface (double that of a monoplane +of the same size) and consequently much greater weight- +carrying capacity. + +Differences in Biplanes. + +While all biplanes are of the same general construction +so far as the main planes are concerned, each aviator +has his own ideas as to the "rigging." + +Wright, for instance, places a double horizontal rudder +in front, with a vertical rudder in the rear. There +are no partitions between the main planes, and the +bicycle wheels used on other forms are replaced by skids. + +Voisin, on the contrary, divides the main planes with +vertical partitions to increase stability in turning; uses +a single-plane horizontal rudder in front, and a big box- +tail with vertical rudder at the rear; also the bicycle +wheels. + +Curtiss attaches horizontal stabilizing surfaces to the +upper plane; has a double horizontal rudder in front, +with a vertical rudder and horizontal stabilizing surfaces +in rear. Also the bicycle wheel alighting gear. + + + +CHAPTER V. + +CONSTRUCTING A GLIDING MACHINE. + +First decide upon the kind of a machine you want-- +monoplane, biplane, or triplane. For a novice the biplane +will, as a rule, be found the most satisfactory as +it is more compact and therefore the more easily handled. +This will be easily understood when we realize that the +surface of a flying machine should be laid out in proportion +to the amount of weight it will have to sustain. +The generally accepted rule is that 152 square feet of +surface will sustain the weight of an average-sized man, +say 170 pounds. Now it follows that if these 152 square +feet of surface are used in one plane, as in the monoplane, +the length and width of this plane must be greater +than if the same amount of surface is secured by using +two planes--the biplane. This results in the biplane +being more compact and therefore more readily manipulated +than the monoplane, which is an important item +for a novice. + +Glider the Basis of Success. + +Flying machines without motors are called gliders. In +making a flying machine you first construct the glider. +If you use it in this form it remains a glider. If you +install a motor it becomes a flying machine. You must +have a good glider as the basis of a successful flying +machine. + +It will be well for the novice, the man who has never +had any experience as an aviator, to begin with a glider +and master its construction and operation before he +essays the more pretentious task of handling a fully- +equipped flying machine. In fact, it is essential that he +should do so. + +Plans for Handy Glider. + +A glider with a spread (advancing edge) of 20 feet, and +a breadth or depth of 4 feet, will be about right to begin +with. Two planes of this size will give the 152 square +yards of surface necessary to sustain a man's weight. +Remember that in referring to flying machine measurements +"spread" takes the place of what would ordinarily +be called "length," and invariably applies to the long +or advancing edge of the machine which cuts into the air. +Thus, a glider is spoken of as being 20 feet spread, and +4 feet in depth. So far as mastering the control of the +machine is concerned, learning to balance one's self in +the air, guiding the machine in any desired direction by +changing the position of the body, etc., all this may be +learned just as readily, and perhaps more so, with a 20- +foot glider than with a larger apparatus. + +Kind of Material Required. + +There are three all-important features in flying machine +construction, viz.: lightness, strength and extreme +rigidity. Spruce is the wood generally used for glider +frames. Oak, ash and hickory are all stronger, but they +are also considerably heavier, and where the saving of +weight is essential, the difference is largely in favor of +spruce. This will be seen in the following table: + + Weight Tensile Compressive + per cubic ft. Strength Strength + Wood in lbs. lbs. per sq. in. lbs. per sq in. +Hickory 53 12,000 8,500 +Oak 50 12,000 9,000 +Ash 38 12,000 6,000 +Walnut 38 8,000 6,000 +Spruce 25 8,000 5,000 +Pine 25 5,000 4,500 + + +Considering the marked saving in weight spruce has +a greater percentage of tensile strength than any of the +other woods. It is also easier to find in long, straight- +grained pieces free from knots, and it is this kind only +that should be used in flying machine construction. + +You will next need some spools or hanks of No. 6 +linen shoe thread, metal sockets, a supply of strong +piano wire, a quantity of closely-woven silk or cotton +cloth, glue, turnbuckles, varnish, etc. + +Names of the Various Parts. + +The long strips, four in number, which form the front +and rear edges of the upper and lower frames, are called +the horizontal beams. These are each 20 feet in length. +These horizontal beams are connected by upright strips, +4 feet long, called stanchions. There are usually 12 of +these, six on the front edge, and six on the rear. They +serve to hold the upper plane away from the lower one. +Next comes the ribs. These are 4 feet in length (projecting +for a foot over the rear beam), and while intended +principally as a support to the cloth covering of +the planes, also tend to hold the frame together in a +horizontal position just as the stanchions do in the vertical. +There are forty-one of these ribs, twenty-one on +the upper and twenty on the lower plane. Then come +the struts, the main pieces which join the horizontal +beams. All of these parts are shown in the illustrations, +reference to which will make the meaning of the +various names clear. + +Quantity and Cost of Material. + +For the horizontal beams four pieces of spruce, 20 feet +long, 1 1/2 inches wide and 3/4 inch thick are necessary. +These pieces must be straight-grain, and absolutely free +from knots. If it is impossible to obtain clear pieces +of this length, shorter ones may be spliced, but this is +not advised as it adds materially to the weight. The +twelve stanchions should be 4 feet long and 7/8 inch in +diameter and rounded in form so as to offer as little +resistance as possible to the wind. The struts, there +are twelve of them, are 3 feet long by 11/4 x 1/2 inch. For +a 20-foot biplane about 20 yards of stout silk or unbleached +muslin, of standard one yard width, will be +needed. The forty-one ribs are each 4 feet long, and +1/2 inch square. A roll of No. 12 piano wire, twenty-four +sockets, a package of small copper tacks, a pot of glue, +and similar accessories will be required. The entire +cost of this material should not exceed $20. The wood +and cloth will be the two largest items, and these should +not cost more than $10. This leaves $10 for the varnish, +wire, tacks, glue, and other incidentals. This estimate +is made for cost of materials only, it being taken for +granted that the experimenter will construct his own +glider. Should the services of a carpenter be required +the total cost will probably approximate $60 or $70. + +Application of the Rudders. + +The figures given also include the expense of rudders, +but the details of these have not been included as the +glider is really complete without them. Some of the best +flights the writer ever saw were made by Mr. A. M. Herring in a +glider without a rudder, and yet there can +be no doubt that a rudder, properly proportioned and +placed, especially a rear rudder, is of great value to the +aviator as it keeps the machine with its head to the +wind, which is the only safe position for a novice. For +initial educational purposes, however, a rudder is not +essential as the glides will, or should, be made on level +ground, in moderate, steady wind currents, and at a +modest elevation. The addition of a rudder, therefore, +may well be left until the aviator has become reasonably +expert in the management of his machine. + +Putting the Machine Together. + +Having obtained the necessary material, the first move +is to have the rib pieces steamed and curved. This curve +may be slight, about 2 inches for the 4 feet. While +this is being done the other parts should be carefully +rounded so the square edges will be taken off. This +may be done with sand paper. Next apply a coat of +shellac, and when dry rub it down thoroughly with fine +sand paper. When the ribs are curved treat them in +the same way. + +Lay two of the long horizontal frame pieces on the +floor 3 feet apart. Between these place six of the strut +pieces. Put one at each end, and each 4 1/2 feet put +another, leaving a 2-foot space in the center. This will +give you four struts 4 1/2 feet apart, and two in the center +2 feet apart, as shown in the illustration. This makes +five rectangles. Be sure that the points of contact are +perfect, and that the struts are exactly at right angles +with the horizontal frames. This is a most important +feature because if your frame "skews" or twists you +cannot keep it straight in the air. Now glue the ends +of the struts to the frame pieces, using plenty of glue, +and nail on strips that will hold the frame in place while +the glue is drying. The next day lash the joints together +firmly with the shoe thread, winding it as you would to +mend a broken gun stock, and over each layer put a +coating of glue. This done, the other frame pieces and +struts may be treated in the same way, and you will thus +get the foundations for the two planes. + +Another Way of Placing Struts. + +In the machines built for professional use a stronger +and more certain form of construction is desired. This +is secured by the placing the struts for the lower plane +under the frame piece, and those for the upper plane +over it, allowing them in each instance to come out flush +with the outer edges of the frame pieces. They are then +securely fastened with a tie plate or clamp which passes +over the end of the strut and is bound firmly against +the surface of the frame piece by the eye bolts of the +stanchion sockets. + +Placing the Rib Pieces. + +Take one of the frames and place on it the ribs, with +the arched side up, letting one end of the ribs come +flush with the front edge of the forward frame, and the +other end projecting about a foot beyond the rear frame. +The manner of fastening the ribs to the frame pieces is +optional. In some cases they are lashed with shoe +thread, and in others clamped with a metal clamp fastened +with 1/2-inch wood screws. Where clamps and +screws are used care should be taken to make slight +holes in the wood with an awl before starting the screws +so as to lessen any tendency to split the wood. On the +top frame, twenty-one ribs placed one foot apart will be +required. On the lower frame, because of the opening +left for the operator's body, you will need only twenty. + +Joining the Two Frames. + +The two frames must now be joined together. For this +you will need twenty-four aluminum or iron sockets +which may be purchased at a foundry or hardware shop. +These sockets, as the name implies, provide a receptacle +in which the end of a stanchion is firmly held, and have +flanges with holes for eye-bolts which hold them firmly +to the frame pieces, and also serve to hold the guy wires. +In addition to these eye-bolt holes there are two others +through which screws are fastened into the frame pieces. +On the front frame piece of the bottom plane place six +sockets, beginning at the end of the frame, and locating +them exactly opposite the struts. Screw the sockets into +position with wood screws, and then put the eye-bolts in +place. Repeat the operation on the rear frame. Next +put the sockets for the upper plane frame in place. + +You are now ready to bring the two planes together. +Begin by inserting the stanchions in the sockets in the +lower plane. The ends may need a little rubbing with +sandpaper to get them into the sockets, but care must +be taken to have them fit snugly. When all the stanchions +are in place on the lower plane, lift the upper +plane into position, and fit the sockets over the upper +ends of the stanchions. + +Trussing with Guy Wires. + +The next move is to "tie" the frame together rigidly +by the aid of guy wires. This is where the No. 12 piano +wire comes in. Each rectangle formed by the struts and +stanchions with the exception of the small center one, +is to be wired separately as shown in the illustration. +At each of the eight corners forming the rectangle the +ring of one of the eye-bolts will be found. There are +two ways of doing this "tieing," or trussing. One is to +run the wires diagonally from eye-bolt to eye-bolt, depending +upon main strength to pull them taut enough, +and then twist the ends so as to hold. The other is to +first make a loop of wire at each eye-bolt, and connect +these loops to the main wires with turn-buckles. This +latter method is the best, as it admits of the tension being +regulated by simply turning the buckle so as to draw +the ends of the wire closer together. A glance at the +illustration will make this plain, and also show how the +wires are to be placed. The proper degree of tension +may be determined in the following manner: + +After the frame is wired place each end on a saw-horse +so as to lift the entire frame clear of the work-shop +floor. Get under it, in the center rectangle and, grasping +the center struts, one in each hand, put your entire +weight on the structure. If it is properly put together +it will remain rigid and unyielding. Should it sag ever +so slightly the tension of the wires must be increased +until any tendency to sag, no matter how slight it may +be, is overcome. + +Putting on the Cloth. + +We are now ready to put on the cloth covering which +holds the air and makes the machine buoyant. The kind +of material employed is of small account so long as it is +light, strong, and wind-proof, or nearly so. Some aviators +use what is called rubberized silk, others prefer +balloon cloth. Ordinary muslin of good quality, treated +with a coat of light varnish after it is in place, will answer +all the purposes of the amateur. + +Cut the cloth into strips a little over 4 feet in length. +As you have 20 feet in width to cover, and the cloth is +one yard wide, you will need seven strips for each plane, +so as to allow for laps, etc. This will give you fourteen +strips. Glue the end of each strip around the front +horizontal beams of the planes, and draw each strip back, +over the ribs, tacking the edges to the ribs as you go +along, with small copper or brass tacks. In doing this +keep the cloth smooth and stretched tight. Tacks should +also be used in addition to the glue, to hold the cloth to +the horizontal beams. + +Next, give the cloth a coat of varnish on the clear, or +upper side, and when this is dry your glider will be +ready for use. + +Reinforcing the Cloth. + +While not absolutely necessary for amateur purposes, +reinforcement of the cloth, so as to avoid any tendency +to split or tear out from wind-pressure, is desirable. One +way of doing this is to tack narrow strips of some +heavier material, like felt, over the cloth where it laps +on the ribs. Another is to sew slips or pockets in the +cloth itself and let the ribs run through them. Still another +method is to sew 2-inch strips (of the same material +as the cover) on the cloth, placing them about one +yard apart, but having them come in the center of each +piece of covering, and not on the laps where the various +pieces are joined. + +Use of Armpieces. + +Should armpieces be desired, aside from those afforded +by the center struts, take two pieces of spruce, 3 feet +long, by 1 x 1 3/4 inches, and bolt them to the front and +rear beams of the lower plane about 14 inches apart. +These will be more comfortable than using the struts, +as the operator will not have to spread his arms so +much. In using the struts the operator, as a rule, takes +hold of them with his hands, while with the armpieces, +as the name implies, he places his arms over them, one +of the strips coming under each armpit. + +Frequently somebody asks why the ribs should be +curved. The answer is easy. The curvature tends to +direct the air downward toward the rear and, as the air +is thus forced downward, there is more or less of an impact +which assists in propelling the aeroplane upwards. + + + +CHAPTER VI. + +LEARNING TO FLY. + +Don't be too ambitious at the start. Go slow, and +avoid unnecessary risks. At its best there is an element +of danger in aviation which cannot be entirely eliminated, but it +may be greatly reduced and minimized by +the use of common sense. + +Theoretically, the proper way to begin a glide is from +the top of an incline, facing against the wind, so that +the machine will soar until the attraction of gravitation +draws it gradually to the ground. This is the manner in +which experienced aviators operate, but it must be kept +in mind that these men are experts. They understand +air currents, know how to control the action and direction +of their machines by shifting the position of their +bodies, and by so doing avoid accidents which would be +unavoidable by a novice. + +Begin on Level Ground. + +Make your first flights on level ground, having a couple +of men to assist you in getting the apparatus under +headway. Take your position in the center rectangle, +back far enough to give the forward edges of the glider +an inclination to tilt upward very slightly. Now start +and run forward at a moderately rapid gait, one man at +each end of the glider assisting you. As the glider cuts +into the air the wind will catch under the uplifted edges +of the curved planes, and buoy it up so that it will rise +in the air and take you with it. This rise will not be +great, just enough to keep you well clear of the ground. +Now project your legs a little to the front so as to shift +the center of gravity a trifle and bring the edges of the +glider on an exact level with the atmosphere. This, with +the momentum acquired in the start, will keep the machine +moving forward for some distance. + +Effect of Body Movements. + +When the weight of the body is slightly back of the +center of gravity the edges of the advancing planes are +tilted slightly upward. The glider in this position acts +as a scoop, taking in the air which, in turn, lifts it off the +ground. When a certain altitude is reached--this varies +with the force of the wind--the tendency to a forward +movement is lost and the glider comes to the ground. +It is to prolong the forward movement as much as possible +that the operator shifts the center of gravity slightly, +bringing the apparatus on an even keel as it were by +lowering the advancing edges. This done, so long as +there is momentum enough to keep the glider moving, it +will remain afloat. + +If you shift your body well forward it will bring the +front edges of the glider down, and elevate the rear ones. +In this way the air will be "spilled" out at the rear, and, +having lost the air support or buoyancy, the glider comes +down to the ground. A few flights will make any ordinary +man proficient in the control of his apparatus by his +body movements, not only as concerns the elevating and +depressing of the advancing edges, but also actual steering. You +will quickly learn, for instance, that, as the +shifting of the bodily weight backwards and forwards +affects the upward and downward trend of the planes, so +a movement sideways--to the left or the right--affects +the direction in which the glider travels. + +Ascends at an Angle. + +In ascending, the glider and flying machine, like the +bird, makes an angular, not a vertical flight. Just what +this angle of ascension may be is difficult to determine. +It is probable and in fact altogether likely, that it varies +with the force of the wind, weight of the rising body, +power of propulsion, etc. This, in the language of physicists, +is the angle of inclination, and, as a general thing, +under normal conditions (still air) should be put down as +about one in ten, or 5 3/4 degrees. This would be an ideal +condition, but it has not, as vet been reached. The force +of the wind affects the angle considerably, as does also +the weight and velocity of the apparatus. In general +practice the angle varies from 23 to 45 degrees. At +more than 45 degrees the supporting effort is overcome +by the resistance to forward motion. + +Increasing the speed or propulsive force, tends to +lessen the angle at which the machine may be successfully +operated because it reduces the wind pressure. +Most of the modern flying machines are operated at an +angle of 23 degrees, or less. + +Maintaining an Equilibrium. + +Stable equilibrium is one of the main essentials to +successful flight, and this cannot be preserved in an +uncertain, gusty wind, especially by an amateur. The +novice should not attempt a glide unless the conditions +are just right. These conditions are: A clear, level +space, without obstructions, such as trees, etc., and a +steady wind of not exceeding twelve miles an hour. Always +fly against the wind. + +When a reasonable amount of proficiency in the handling +of the machine on level ground has been acquired +the field of practice may be changed to some gentle +slope. In starting from a slope it will be found easier +to keep the machine afloat, but the experience at first is +likely to be very disconcerting to a man of less than iron +nerve. As the glider sails away from the top of the +slope the distance between him and the ground increases +rapidly until the aviator thinks he is up a hundred miles +in the air. If he will keep cool, manipulate his apparatus +so as to preserve its equilibrium, and "let nature take its +course," he will come down gradually and safely to the +ground at a considerable distance from the starting place. +This is one advantage of starting from an elevation-- +your machine will go further. + +But, if the aviator becomes "rattled"; if he loses control +of his machine, serious results, including a bad fall +with risk of death, are almost certain. And yet this +practice is just as necessary as the initial lessons on +level ground. When judgment is used, and "haste made +slowly," there is very little real danger. While experimenting +with gliders the Wrights made flights innumerable +under all sorts of conditions and never had an accident +of any kind. + +Effects of Wind Currents. + +The larger the machine the more difficult it will be to +control its movements in the air, and yet enlargement is +absolutely necessary as weight, in the form of motor, +rudder, etc., is added. + +Air currents near the surface of the ground are diverted +by every obstruction unless the wind is blowing +hard enough to remove the obstruction entirely. Take, +for instance, the case of a tree or shrub, in a moderate +wind of from ten to twelve miles an hour. As the wind +strikes the tree it divides, part going to one side and +part going to the other, while still another part is directed +upward and goes over the top of the obstruction. +This makes the handling of a glider on an obstructed +field difficult and uncertain. To handle a glider successfully +the place of operation should be clear and the wind +moderate and steady. If it is gusty postpone your flight. +In this connection it will be well to understand the velocity +of the wind, and what it means as shown in the +following table: + +Miles per hour Feet per second Pressure per sq. foot + 10 14.7 .492 + 25 36.7 3.075 + 50 73.3 12.300 + 100 146.6 49.200 + +Pressure of wind increases in proportion to the square +of the velocity. Thus wind at 10 miles an hour has four +times the pressure of wind at 5 miles an hour. The +greater this pressure the large and heavier the object +which can be raised. Any boy who has had experience +in flying kites can testify to this, High winds, however, +are almost invariably gusty and uncertain as to direction, +and this makes them dangerous for aviators. It +is also a self-evident fact that, beyond a certain stage, +the harder the wind blows the more difficult it is to +make headway against it. + +Launching Device for Gliders. + +On page 195 will be found a diagram of the various +parts of a launcher for gliders, designed and patented +by Mr. Octave Chanute. In describing this invention +in Aeronautics, Mr. Chanute says: + +"In practicing, the track, preferably portable, is +generally laid in the direction of the existing wind and +the car, preferably a light platform-car, is placed on the +track. The truck carrying the winding-drum and its motor +is placed to windward a suitable distance--say from +two hundred to one thousand feet--and is firmly blocked +or anchored in line with the portable track, which is +preferably 80 or 100 feet in length. The flying or gliding +machine to be launched with its operator is placed on +the platform-car at the leeward end of the portable track. +The line, which is preferably a flexible combination +wire-and-cord cable, is stretched between the winding- +drum on the track and detachably secured to the flying +or gliding machine, preferably by means of a trip-hoop, +or else held in the hand of the operator, so that the +operator may readily detach the same from the flying- +machine when the desired height is attained. + +How Glider Is Started. + +"Then upon a signal given by the operator the engineer +at the motor puts it into operation, gradually increasing +the speed until the line is wound upon the drum +at a maximum speed of, say, thirty miles an hour. The +operator of the flying-machine, whether he stands upright and +carries it on his shoulders, or whether he sits +or lies down prone upon it, adjusts the aeroplane or +carrying surfaces so that the wind shall strike them on +the top and press downward instead of upward until +the platform-car under action of the winding-drum and +line attains the required speed. + +"When the operator judges that his speed is sufficient, +and this depends upon the velocity of the wind as well +as that of the car moving against the wind, he quickly +causes the front of the flying-machine to tip upward, so +that the relative wind striking on the under side of the +planes or carrying surfaces shall lift the flying machine +into the air. It then ascends like a kite to such height +as may be desired by the operator, who then trips the +hook and releases the line from the machine. + +What the Operator Does. + +"The operator being now free in the air has a certain +initial velocity imparted by the winding-drum and line +and also a potential energy corresponding to his height +above the ground. If the flying or gliding machine is +provided with a motor, he can utilize that in his further +flight, and if it is a simple gliding machine without +motor he can make a descending flight through the air +to such distance as corresponds to the velocity acquired +and the height gained, steering meanwhile by the devices +provided for that purpose. + +"The simplest operation or maneuver is to continue +the flight straight ahead against the wind; but it is possible +to vary this course to the right or left, or even to +return in downward flight with the wind to the vicinity +of the starting-point. Upon nearing the ground the +operator tips upward his carrying-surfaces and stops his +headway upon the cushion of increased air resistance +so caused. The operator is in no way permanently +fastened to his machine, and the machine and the operator +simply rest upon the light platform-car, so that +the operator is free to rise with the machine from the +car whenever the required initial velocity is attained. + +Motor For the Launcher. + +"The motor may be of any suitable kind or construction, +but is preferably an electric or gasolene motor. +The winding-drum is furnished with any suitable or customary +reversing-guide to cause the line to wind smoothly +and evenly upon the drum. The line is preferably a +cable composed of flexible wire and having a cotton or +other cord core to increase its flexibility. The line +extends from the drum to the flying or gliding machine. +Its free end may, if desired, be grasped and held by the +operator until the flying-machine ascends to the desired +height, when by simply letting go of the line the operator +may continue his flight free. The line, however, is preferably +connected to the flying or gliding machine +directly by a trip-hook having a handle or trip lever +within reach of the operator, so that when he ascends +to the required height he may readily detach the line +from the flying or gliding machine." + + + +CHAPTER VII. + +PUTTING ON THE RUDDER. + +Gliders as a rule have only one rudder, and this is in +the rear. It tends to keep the apparatus with its head to +the wind. Unlike the rudder on a boat it is fixed and +immovable. The real motor-propelled flying machine, +generally has both front and rear rudders manipulated +by wire cables at the will of the operator. + +Allowing that the amateur has become reasonably expert +in the manipulation of the glider he should, before +constructing an actual flying machine, equip his glider +with a rudder. + +Cross Pieces for Rudder Beam. + +To do this he should begin by putting in a cross piece, +2 feet long by 1/4x3/4 inches between the center struts, +in the lower plane. This may be fastened to the struts +with bolts or braces. The former method is preferable. +On this cross piece, and on the rear frame of the plane +itself, the rudder beam is clamped and bolted. This +rudder beam is 8 feet 11 inches long. Having put these +in place duplicate them in exactly the same manner and +dimensions from the upper frame The cross pieces on +which the ends of the rudder beams are clamped should +be placed about one foot in advance of the rear frame +beam. + +The Rudder Itself. + +The next step is to construct the rudder itself. This +consists of two sections, one horizontal, the other vertical. +The latter keeps the aeroplane headed into the wind, +while the former keeps it steady--preserves the equilibrium. + +The rudder beams form the top and bottom frames of +the vertical rudder. To these are bolted and clamped +two upright pieces, 3 feet, 10 inches in length, and 3/4 +inch in cross section. These latter pieces are placed about +two feet apart. This completes the framework of the +vertical rudder. See next page (59). + +For the horizontal rudder you will require two strips +6 feet long, and four 2 feet long. Find the exact center +of the upright pieces on the vertical rudder, and at this +spot fasten with bolts the long pieces of the horizontal, +placing them on the outside of the vertical strips. Next +join the ends of the horizontal strips with the 2-foot +pieces, using small screws and corner braces. This done +you will have two of the 2-foot pieces left. These go in +the center of the horizontal frame, "straddling" the +vertical strips, as shown in the illustration. + +The framework is to be covered with cloth in the +same manner as the planes. For this about ten yards +will be needed. + +Strengthening the Rudder. + +To ensure rigidity the rudder must be stayed with +guy wires. For this purpose the No. 12 piano wire is +the best. Begin by running two of these wires from the +top eye-bolts of stanchions 3 and 4, page 37, to rudder +beam where it joins the rudder planes, fastening them +at the bottom. Then run two wires from the top of the +rudder beam at the same point, to the bottom eye-bolts +of the same stanchions. This will give you four diagonal +wires reaching from the rudder beam to the top +and bottom planes of the glider. Now, from the outer +ends of the rudder frame run four similar diagonal wires +to the end of the rudder beam where it rests on the +cross piece. You will then have eight truss wires +strengthening the connection of the rudder to the main +body of the glider. + +The framework of the rudder planes is then to be +braced in the same way, which will take eight more +wires, four for each rudder plane. All the wires are +to be connected at one end with turn-buckles so the +tension may be regulated as desired. + +In forming the rudder frame it will be well to mortise +the corners, tack them together with small nails, and +then put in a corner brace in the inside of each joint. +In doing this bear in mind that the material to be thus +fastened is light, and consequently the lightest of nails, +screws, bolts and corner pieces, etc., is necessary. + + + +CHAPTER VIII. + +THE REAL FLYING MACHINE. + +We will now assume that you have become proficient +enough to warrant an attempt at the construction of a +real flying machine--one that will not only remain suspended +in the air at the will of the operator, but make +respectable progress in whatever direction he may desire to go. +The glider, it must be remembered, is not +steerable, except to a limited extent, and moves only in +one direction--against the wind. Besides this its power +of flotation--suspension in the air--is circumscribed. + +Larger Surface Area Required. + +The real flying machine is the glider enlarged, and +equipped with motor and propeller. The first thing to +do is to decide upon the size required. While a glider +of 20 foot spread is large enough to sustain a man it +could not under any possible conditions, be made to rise +with the weight of the motor, propeller and similar +equipment added. As the load is increased so must the +surface area of the planes be increased. Just what this +increase in surface area should be is problematical as +experienced aviators disagree, but as a general proposition +it may be placed at from three to four times the area of +a 20-foot glider.[3] + +[3] See Chapter XXV. + +Some Practical Examples. + +The Wrights used a biplane 41 feet in spread, and 6 1/2 +ft. deep. This, for the two planes, gives a total surface +area of 538 square feet, inclusive of auxiliary planes. +This sustains the engine equipment, operator, etc., a total +weight officially announced at 1,070 pounds. It shows +a lifting capacity of about two pounds to the square +foot of plane surface, as against a lifting capacity of +about 1/2 pound per square foot of plane surface for the +20-foot glider. This same Wright machine is also reported +to have made a successful flight, carrying a total +load of 1,100 pounds, which would be over two pounds +for each square foot of surface area, which, with auxiliary +planes, is 538 square feet. + +To attain the same results in a monoplane, the single +surface would have to be 60 feet in spread and 9 feet +deep. But, while this is the mathematical rule, Bleriot +has demonstrated that it does not always hold good. +On his record-breaking trip across the English channel, +July 25th, 1909, the Frenchman was carried in a +monoplane 24 1/2 feet in spread, and with a total sustaining +surface of 150 1/2 square feet. The total weight of +the outfit, including machine, operator and fuel sufficient +for a three-hour run, was only 660 pounds. With +an engine of (nominally) 25 horsepower the distance of +21 miles was covered in 37 minutes. + +Which is the Best? + +Right here an established mathematical quantity is +involved. A small plane surface offers less resistance +to the air than a large one and consequently can attain +a higher rate of speed. As explained further on in this +chapter speed is an important factor in the matter of +weight-sustaining capacity. A machine that travels one- +third faster than another can get along with one-half the +surface area of the latter without affecting the load. See +the closing paragraph of this chapter on this point. In +theory the construction is also the simplest, but this is +not always found to be so in practice. The designing +and carrying into execution of plans for an extensive +area like that of a monoplane involves great skill and +cleverness in getting a framework that will be strong +enough to furnish the requisite support without an undue excess +of weight. This proposition is greatly simplified +in the biplane and, while the speed attained by the latter +may not be quite so great as that of the monoplane, it +has much larger weight-carrying capacity. + +Proper Sizes For Frame. + +Allowing that the biplane form is selected the construction +may be practically identical with that of the +20-foot glider described in Chapter V., except as to size +and elimination of the armpieces. In size the surface +planes should be about twice as large as those of the +20-foot glider, viz: 40 feet spread instead of 20, and 6 feet +deep instead of 3. The horizontal beams, struts, stanchions, +ribs, etc., should also be increased in size proportionately. + +While care in the selection of clear, straight-grained +timber is important in the glider, it is still more important +in the construction of a motor-equipped flying +machine as the strain on the various parts will be much +greater. + +How to Splice Timbers. + +It is practically certain that you will have to resort to +splicing the horizontal beams as it will be difficult, if not +impossible, to find 40-foot pieces of timber totally free +from knots and worm holes, and of straight grain. + +If splicing is necessary select two good 20-foot pieces, +3 inches wide and 1 1/2 inches thick, and one 10-foot long, +of the same thickness and width. Plane off the bottom +sides of the 10-foot strip, beginning about two feet back +from each end, and taper them so the strip will be about +3/4 inch thick at the extreme ends. Lay the two 20-foot +beams end to end, and under the joint thus made place +the 10-foot strip, with the planed-off ends downward. +The joint of the 20-foot pieces should be directly in the +center of the 10-foot piece. Bore ten holes (with a 1/4- +inch augur) equi-distant apart through the 20-foot +strips and the 10-foot strip under them. Through these +holes run 1/4-inch stove bolts with round, beveled heads. +In placing these bolts use washers top and bottom, one +between the head and the top beam, and the other between +the bottom beam and the screw nut which holds +the bolt. Screw the nuts down hard so as to bring the +two beams tightly together, and you will have a rigid +40-foot beam. + +Splicing with Metal Sleeves. + +An even better way of making a splice is by tonguing +and grooving the ends of the frame pieces and enclosing +them in a metal sleeve, but it requires more mechanical +skill than the method first named. The operation of +tonguing and grooving is especially delicate and calls +for extreme nicety of touch in the handling of tools, but +if this dexterity is possessed the job will be much more +satisfactory than one done with a third timber. + +As the frame pieces are generally about 1 1/2 inch in +diameter, the tongue and the groove into which the +tongue fits must be correspondingly small. Begin by +sawing into one side of one of the frame pieces about 4 +inches back from the end. Make the cut about 1/2 inch +deep. Then turn the piece over and duplicate the cut. +Next saw down from the end to these cuts. When the +sawed-out parts are removed you will have a "tongue" +in the end of the frame timber 4 inches long and 1/2 inch +thick. The next move is to saw out a 5/8-inch groove in +the end of the frame piece which is to be joined. You +will have to use a small chisel to remove the 5/8-inch bit. +This will leave a groove into which the tongue will fit +easily. + +Joining the Two Pieces. + +Take a thin metal sleeve--this is merely a hollow tube +of aluminum or brass open at each end--8 inches long, +and slip it over either the tongued or grooved end of one +of the frame timbers. It is well to have the sleeve fit +snugly, and this may necessitate a sand-papering of the +frame pieces so the sleeve will slip on. + +Push the sleeve well back out of the way. Cover the +tongue thoroughly with glue, and also put some on the +inside of the groove. Use plenty of glue. Now press +the tongue into the groove, and keep the ends firmly +together until the glue is thoroughly dried. Rub off the +joint lightly with sand-paper to remove any of the glue +which may have oozed out, and slip the sleeve into place +over the joint. Tack the sleeve in position with small +copper tacks, and you will have an ideal splice. + +The same operation is to be repeated on each of the +four frame pieces. Two 20-foot pieces joined in this +way will give a substantial frame, but when suitable +timber of this kind can not be had, three pieces, each 6 +feet 11 inches long, may be used. This would give 20 +feet 9 inches, of which 8 inches will be taken up in the +two joints, leaving the frame 20 feet 1 inch long. + +Installation of Motor. + +Next comes the installation of the motor. The kinds +and efficiency of the various types are described in the +following chapter (IX). All we are interested in at +this point is the manner of installation. This varies +according to the personal ideas of the aviator. Thus one +man puts his motor in the front of his machine, another +places it in the center, and still another finds the rear of +the frame the best. All get good results, the comparative +advantages of which it is difficult to estimate. Where +one man, as already explained, flies faster than another, +the one beaten from the speed standpoint has an advantage +in the matter of carrying weight, etc. + +The ideas of various well-known aviators as to the +correct placing of motors may be had from the following: + +Wrights--In rear of machine and to one side. + +Curtiss--Well to rear, about midway between upper +and lower planes. + +Raich--In rear, above the center. + +Brauner-Smith--In exact center of machine. + +Van Anden--In center. + +Herring-Burgess--Directly behind operator. + +Voisin--In rear, and on lower plane. + +Bleriot--In front. + +R. E. P.--In front. + +The One Chief Object. + +An even distribution of the load so as to assist in +maintaining the equilibrium of the machine, should be +the one chief object in deciding upon the location of the +motor. It matters little what particular spot is selected +so long as the weight does not tend to overbalance the +machine, or to "throw it off an even keel." It is just +like loading a vessel, an operation in which the expert +seeks to so distribute the weight of the cargo as to keep +the vessel in a perfectly upright position, and prevent a +"list" or leaning to one side. The more evenly the cargo +is distributed the more perfect will be the equilibrium of +the vessel and the better it can be handled. Sometimes, +when not properly stowed, the cargo shifts, and this at +once affects the position of the craft. When a ship +"lists" to starboard or port a preponderating weight of +the cargo has shifted sideways; if bow or stern is unduly +depressed it is a sure indication that the cargo has shifted +accordingly. In either event the handling of the craft +becomes not only difficult, but extremely hazardous. +Exactly the same conditions prevail in the handling of a +flying machine. + +Shape of Machine a Factor. + +In placing the motor you must be governed largely by +the shape and construction of the flying machine frame. +If the bulk of the weight of the machine and auxiliaries +is toward the rear, then the natural location for the motor +will be well to the front so as to counterbalance the +excess in rear weight. In the same way if the +preponderance of the weight is forward, then the motor +should be placed back of the center. + +As the propeller blade is really an integral part of the +motor, the latter being useless without it, its placing +naturally depends upon the location selected for the +motor. + +Rudders and Auxiliary Planes. + +Here again there is great diversity of opinion among +aviators as to size, location and form. The striking +difference of ideas in this respect is well illustrated in +the choice made by prominent makers as follows: + +Voisin--horizontal rudder, with two wing-like planes, +in front; box-like longitudinal stability plane in rear, +inside of which is a vertical rudder. + +Wright--large biplane horizontal rudder in front at +considerable distance--about 10 feet--from the main +planes; vertical biplane rudder in rear; ends of upper +and lower main planes made flexible so they may be +moved. + +Curtiss--horizontal biplane rudder, with vertical damping +plane between the rudder planes about 10 feet in +front of main planes; vertical rudder in rear; stabilizing +planes at each end of upper main plane. + +Bleriot--V-shaped stabilizing fin, projecting from rear +of plane, with broad end outward; to the broad end of +this fin is hinged a vertical rudder; horizontal biplane +rudder, also in rear, under the fin. + +These instances show forcefully the wide diversity of +opinion existing among experienced aviators as to the +best manner of placing the rudders and stabilizing, or +auxiliary planes, and make manifest how hopeless would +be the task of attempting to select any one form and +advise its exclusive use. + +Rudder and Auxiliary Construction. + +The material used in the construction of the rudders +and auxiliary planes is the same as that used in the main +planes--spruce for the framework and some kind of +rubberized or varnished cloth for the covering. The +frames are joined and wired in exactly the same manner +as the frames of the main planes, the purpose being to +secure the same strength and rigidity. Dimensions of +the various parts depend upon the plan adopted and the +size of the main plane. + +No details as to exact dimensions of these rudders and +auxiliary planes are obtainable. The various builders, +while willing enough to supply data as to the general +measurements, weight, power, etc., of their machines, +appear to have overlooked the details of the auxiliary +parts, thinking, perhaps, that these were of no particular +import to the general public. In the Wright machine, the +rear horizontal and front vertical rudders may be set +down as being about one-quarter (probably a little less) +the size of the main supporting planes. + +Arrangement of Alighting Gear. + +Most modern machines are equipped with an alighting +gear, which not only serves to protect the machine and +aviator from shock or injury in touching the ground, but +also aids in getting under headway. All the leading +makes, with the exception of the Wright, are furnished +with a frame carrying from two to five pneumatic rubber- +tired bicycle wheels. In the Curtiss and Voisin +machines one wheel is placed in front and two in the +rear. In the Bleriot and other prominent machines the +reverse is the rule--two wheels in front and one in the +rear. Farman makes use of five wheels, one in the, +extreme rear, and four, arranged in pairs, a little to the +front of the center of the main lower plane. + +In place of wheels the Wright machine is equipped +with a skid-like device consisting of two long beams +attached to the lower plane by stanchions and curving +up far in front, so as to act as supports to the horizontal +rudder. + +Why Wood Is Favored. + +A frequently asked question is: "Why is not aluminum, +or some similar metal, substituted for wood." +Wood, particularly spruce, is preferred because, weight +considered, it is much stronger than aluminum, and this +is the lightest of all metals. In this connection the following +table will be of interest: + + Compressive + Weight Tensile Strength Strength + per cubic foot per sq. inch per sq. inch +Material in lbs. in lbs. in lbs. +Spruce . . . . 25 8,000 5,000 +Aluminum 162 16,000 ...... +Brass (sheet) 510 23,000 12,000 +Steel (tool) 490 100,000 40,000 +Copper (sheet) 548 30,000 40,000 + +As extreme lightness, combined with strength, +especially tensile strength, is the great essential in flying- +machine construction, it can be readily seen that the +use of metal, even aluminum, for the framework, is +prohibited by its weight. While aluminum has double the +strength of spruce wood it is vastly heavier, and thus +the advantage it has in strength is overbalanced many +times by its weight. The specific gravity of aluminum +is 2.50; that of spruce is only 0.403. + +Things to Be Considered. + +In laying out plans for a flying machine there are five +important points which should be settled upon before +the actual work of construction is started. These are: + +First--Approximate weight of the machine when finished +and equipped. + +Second--Area of the supporting surface required. + +Third--Amount of power that will be necessary to +secure the desired speed and lifting capacity. + +Fourth--Exact dimensions of the main framework +and of the auxiliary parts. + +Fifth--Size, speed and character of the propeller. + +In deciding upon these it will be well to take into +consideration the experience of expert aviators regarding +these features as given elsewhere. (See Chapter X.) + +Estimating the Weights Involved. + +In fixing upon the probable approximate weight in +advance of construction much, of course, must be assumed. +This means that it will be a matter of advance +estimating. If a two-passenger machine is to be built +we will start by assuming the maximum combined +weight of the two people to be 350 pounds. Most of +the professional aviators are lighter than this. Taking +the medium between the weights of the Curtiss and +Wright machines we have a net average of 850 pounds +for the framework, motor, propeller, etc. This, with +the two passengers, amounts to 1,190 pounds. As the +machines quoted are in successful operation it will be +reasonable to assume that this will be a safe basis to +operate on. + +What the Novice Must Avoid. + +This does not mean, however, that it will be safe to +follow these weights exactly in construction, but that +they will serve merely as a basis to start from. Because +an expert can turn out a machine, thoroughly equipped, +of 850 pounds weight, it does not follow that a novice +can do the same thing. The expert's work is the result +of years of experience, and he has learned how to construct +frames and motor plants of the utmost lightness +and strength. + +It will be safer for the novice to assume that he can +not duplicate the work of such men as Wright and Curtiss +without adding materially to the gross weight of +the framework and equipment minus passengers. + +How to Distribute the Weight. + +Let us take 1,030 pounds as the net weight of the machine +as against the same average in the Wright and +Curtiss machines. Now comes the question of distributing +this weight between the framework, motor, and +other equipment. As a general proposition the framework +should weigh about twice as much as the complete +power plant (this is for amateur work). + +The word "framework" indicates not only the wooden +frames of the main planes, auxiliary planes, rudders, +etc., but the cloth coverings as well--everything in fact +except the engine and propeller. + +On the basis named the framework would weigh 686 +pounds, and the power plant 344. These figures are +liberal, and the results desired may be obtained well +within them as the novice will learn as he makes progress +in the work. + +Figuring on Surface Area. + +It was Prof. Langley who first brought into prominence +in connection with flying machine construction the +mathematical principle that the larger the object the +smaller may be the relative area of support. As explained +in Chapter XIII, there are mechanical limits as +to size which it is not practical to exceed, but the main +principle remains in effect. + +Take two aeroplanes of marked difference in area of +surface. The larger will, as a rule, sustain a greater +weight in relative proportion to its area than the smaller +one, and do the work with less relative horsepower. As +a general thing well-constructed machines will average +a supporting capacity of one pound for every one-half +square foot of surface area. Accepting this as a working +rule we find that to sustain a weight of 1,200 pounds +--machine and two passengers--we should have 600 +square feet of surface. + +Distributing the Surface Area. + +The largest surfaces now in use are those of the +Wright, Voisin and Antoinette machines--538 square +feet in each. The actual sustaining power of these machines, +so far as known, has never been tested to the +limit; it is probable that the maximum is considerably +in excess of what they have been called upon to show. +In actual practice the average is a little over one pound +for each one-half square foot of surface area. + +Allowing that 600 square feet of surface will be used, +the next question is how to distribute it to the best +advantage. This is another important matter in which +individual preference must rule. We have seen how +the professionals disagree on this point, some using +auxiliary planes of large size, and others depending upon +smaller auxiliaries with an increase in number so as to +secure on a different plan virtually the same amount of +surface. + +In deciding upon this feature the best thing to do is +to follow the plans of some successful aviator, increasing +the area of the auxiliaries in proportion to the increase +in the area of the main planes. Thus, if you use 600 +square feet of surface where the man whose plans you +are following uses 500, it is simply a matter of making +your planes one-fifth larger all around. + +The Cost of Production. + +Cost of production will be of interest to the amateur +who essays to construct a flying machine. Assuming +that the size decided upon is double that of the glider +the material for the framework, timber, cloth, wire, etc., +will cost a little more than double. This is because it +must be heavier in proportion to the increased size of +the framework, and heavy material brings a larger price +than the lighter goods. If we allow $20 as the cost of +the glider material it will be safe to put down the cost +of that required for a real flying machine framework +at $60, provided the owner builds it himself. + +As regards the cost of motor and similar equipment +it can only be said that this depends upon the selection +made. There are some reliable aviation motors which +may be had as low as $500, and there are others which +cost as much as $2,000. + +Services of Expert Necessary. + +No matter what kind of a motor may be selected the +services of an expert will be necessary in its proper +installation unless the amateur has considerable genius +in this line himself. As a general thing $25 should be +a liberal allowance for this work. No matter how carefully +the engine may be placed and connected it will be +largely a matter of luck if it is installed in exactly the +proper manner at the first attempt. The chances are +that several alterations, prompted by the results of trials, +will have to be made. If this is the case the expert's bill may +readily run up to $50. If the amateur is competent to do this +part of the work the entire item of $50 may, of course, be cut +out. + +As a general proposition a fairly satisfactory flying machine, +one that will actually fly and carry the operator with it, may be +constructed for $750, but it will lack the better qualities which +mark the higher priced machines. This computation is made on +the basis of $60 for material, $50 for services of expert, $600 +for motor, etc., and an allowance of $40 for extras. + +No man who has the flying machine germ in his system will be long +satisfied with his first moderate price machine, no matter how +well it may work. It's the old story of the automobile "bug" +over again. The man who starts in with a modest $1,000 automobile +invariably progresses by easy stages to the $4,000 or $5,000 +class. The natural tendency is to want the biggest and best +attainable within the financial reach of the owner. + +It's exactly the same way with the flying machine +convert. The more proficient he becomes in the manipulation +of his car, the stronger becomes the desire to fly +further and stay in the air longer than the rest of his +brethren. This necessitates larger, more powerful, and +more expensive machines as the work of the germ progresses. + +Speed Affects Weight Capacity. + +Don't overlook the fact that the greater speed you +can attain the smaller will be the surface area you can +get along with. If a machine with 500 square feet of +sustaining surface, traveling at a speed of 40 miles an +hour, will carry a weight of 1,200 pounds, we can cut +the sustaining surface in half and get along with 250 +square feet, provided a speed of 60 miles an hour can +be obtained. At 100 miles an hour only 80 square feet +of surface area would be required. In both instances the +weight sustaining capacity will remain the same as with +the 500 square feet of surface area--1,200 pounds. + +One of these days some mathematical genius will +figure out this problem with exactitude and we will have +a dependable table giving the maximum carrying capacity +of various surface areas at various stated speeds, +based on the dimensions of the advancing edges. At +present it is largely a matter of guesswork so far as +making accurate computation goes. Much depends upon +the shape of the machine, and the amount of surface +offering resistance to the wind, etc. + + + +CHAPTER IX. + +SELECTION OF THE MOTOR. + +Motors for flying machines must be light in weight, +of great strength, productive of extreme speed, and +positively dependable in action. It matters little +as to the particular form, or whether air or +water cooled, so long as the four features named are +secured. There are at least a dozen such motors or +engines now in use. All are of the gasolene type, and +all possess in greater or lesser degree the desired qualities. +Some of these motors are: + +Renault--8-cylinder, air-cooled; 50 horse power; +weight 374 pounds. + +Fiat--8-cylinder, air-cooled; 50 horse power; weight +150 pounds. + +Farcot--8-cylinder, air-cooled; from 30 to 100 horse +power, according to bore of cylinders; weight of smallest, +84 pounds. + +R. E. P.--10-cylinder, air-cooled; 150 horse power; +weight 215 pounds. + +Gnome--7 and 14 cylinders, revolving type, air-cooled; +50 and 100 horse power; weight 150 and 300 pounds. + +Darracq--2 to 14 cylinders, water cooled; 30 to 200 +horse power; weight of smallest 100 pounds. + +Wright--4-cylinder, water-cooled; 25 horse power; +weight 200 pounds. + +Antoinette--8 and 16-cylinder, water-cooled; 50 and 100 +horse power; weight 250 and 500 pounds. + +E. N. V.--8-cylinder, water-cooled; from 30 to 80 +horse power, according to bore of cylinder; weight 150 +to 400 pounds. + +Curtiss--8-cylinder, water-cooled; 60 horse power; +weight 300 pounds. + +Average Weight Per Horse Power. + +It will be noticed that the Gnome motor is unusually +light, being about three pounds to the horse power +produced, as opposed to an average of 4 1/2 pounds per +horse power in other makes. This result is secured by +the elimination of the fly-wheel, the engine itself revolving, +thus obtaining the same effect that would be produced +by a fly-wheel. The Farcot is even lighter, being +considerably less than three pounds per horse power, +which is the nearest approach to the long-sought engine +equipment that will make possible a complete flying +machine the total weight of which will not exceed one +pound per square foot of area. + +How Lightness Is Secured. + +Thus far foreign manufacturers are ahead of Americans +in the production of light-weight aerial motors, as +is evidenced by the Gnome and Farcot engines, both of +which are of French make. Extreme lightness is made +possible by the use of fine, specially prepared steel for +the cylinders, thus permitting them to be much thinner +than if ordinary forms of steel were used. Another big +saving in weight is made by substituting what are +known as "auto lubricating" alloys for bearings. These +alloys are made of a combination of aluminum and magnesium. + +Still further gains are made in the use of alloy steel +tubing instead of solid rods, and also by the paring away +of material wherever it can be done without sacrificing +strength. This plan, with the exclusive use of the best +grades of steel, regardless of cost, makes possible a +marked reduction in weight. + +Multiplicity of Cylinders. + +Strange as it may seem, multiplicity of cylinders does +not always add proportionate weight. Because a 4- +cylinder motor weighs say 100 pounds, it does not necessarily +follow that an 8-cylinder equipment will weigh +200 pounds. The reason of this will be plain when it +is understood that many of the parts essential to a 4- +cylinder motor will fill the requirements of an 8-cylinder +motor without enlargement or addition. + +Neither does multiplying the cylinders always increase +the horsepower proportionately. If a 4-cylinder +motor is rated at 25 horsepower it is not safe to take +it for granted that double the number of cylinders will +give 50 horsepower. Generally speaking, eight cylinders, +the bore, stroke and speed being the same, will give +double the power that can be obtained from four, but +this does not always hold good. Just why this exception +should occur is not explainable by any accepted rule. + +Horse Power and Speed. + +Speed is an important requisite in a flying-machine +motor, as the velocity of the aeroplane is a vital factor +in flotation. At first thought, the propeller and similar +adjuncts being equal, the inexperienced mind would +naturally argue that a 50-horsepower engine should +produce just double the speed of one of 25-horsepower. +That this is a fallacy is shown by actual performances. +The Wrights, using a 25-horsepower motor, have made +44 miles an hour, while Bleriot, with a 50-horsepower +motor, has a record of a short-distance flight at the rate +of 52 miles an hour. The fact is that, so far as speed +is concerned, much depends upon the velocity of the +wind, the size and shape of the aeroplane itself, and the +size, shape and gearing of the propeller. The stronger +the wind is blowing the easier it will be for the aeroplane +to ascend, but at the same time the more difficult +it will be to make headway against the wind in a horizontal +direction. With a strong head wind, and proper +engine force, your machine will progress to a certain +extent, but it will be at an angle. If the aviator desired +to keep on going upward this would be all right, but +there is a limit to the altitude which it is desirable to +reach--from 100 to 500 feet for experts--and after that +it becomes a question of going straight ahead. + +Great Waste of Power. + +One thing is certain--even in the most efficient of +modern aerial motors there is a great loss of power between +the two points of production and effect. The +Wright outfit, which is admittedly one of the most effective +in use, takes one horsepower of force for the raising +and propulsion of each 50 pounds of weight. This, +for a 25-horsepower engine, would give a maximum lifting +capacity of 1250 pounds. It is doubtful if any of the +higher rated motors have greater efficiency. As an 8- +cylinder motor requires more fuel to operate than a 4- +cylinder, it naturally follows that it is more expensive +to run than the smaller motor, and a normal increase in +capacity, taking actual performances as a criterion, is +lacking. In other words, what is the sense of using an +8-cylinder motor when one of 4 cylinders is sufficient? + +What the Propeller Does. + +Much of the efficiency of the motor is due to the form +and gearing of the propeller. Here again, as in other +vital parts of flying-machine mechanism, we have a wide +divergence of opinion as to the best form. A fish makes +progress through the water by using its fins and tail; +a bird makes its way through the air in a similar manner +by the use of its wings and tail. In both instances the +motive power comes from the body of the fish or bird. + +In place of fins or wings the flying machine is equipped +with a propeller, the action of which is furnished by the +engine. Fins and wings have been tried, but they don't +work. + +While operating on the same general principle, aerial +propellers are much larger than those used on boats. +This is because the boat propeller has a denser, more +substantial medium to work in (water), and consequently +can get a better "hold," and produce more propulsive +force than one of the same size revolving in the air. +This necessitates the aerial propellers being much larger +than those employed for marine purposes. Up to this +point all aviators agree, but as to the best form most of +them differ. + +Kinds of Propellers Used. + +One of the most simple is that used by Curtiss. It +consists of two pear-shaped blades of laminated wood, +each blade being 5 inches wide at its extreme point, +tapering slightly to the shaft connection. These blades +are joined at the engine shaft, in a direct line. The propeller +has a pitch of 5 feet, and weighs, complete, less +than 10 pounds. The length from end to end of the two +blades is 6 1/2 feet. + +Wright uses two wooden propellers, in the rear of his +biplane, revolving in opposite directions. Each propeller +is two-bladed. + +Bleriot also uses a two-blade wooden propeller, but +it is placed in front of his machine. The blades are each +about 3 1/2 feet long and have an acute "twist." + +Santos-Dumont uses a two-blade wooden propeller, +strikingly similar to the Bleriot. + +On the Antoinette monoplane, with which good records +have been made, the propeller consists of two spoon- +shaped pieces of metal, joined at the engine shaft in +front, and with the concave surfaces facing the machine. + +The propeller on the Voisin biplane is also of metal, +consisting of two aluminum blades connected by a forged +steel arm. + +Maximum thrust, or stress--exercise of the greatest +air-displacing force--is the object sought. This, according +to experts, is best obtained with a large propeller +diameter and reasonably low speed. The diameter is the +distance from end to end of the blades, which on the +largest propellers ranges from 6 to 8 feet. The larger +the blade surface the greater will be the volume of air +displaced, and, following this, the greater will be the +impulse which forces the aeroplane ahead. In all centrifugal +motion there is more or less tendency to disintegration +in the form of "flying off" from the center, and +the larger the revolving object is the stronger is this +tendency. This is illustrated in the many instances in +which big grindstones and fly-wheels have burst from +being revolved too fast. To have a propeller break +apart in the air would jeopardize the life of the aviator, +and to guard against this it has been found best to make +its revolving action comparatively slow. Besides this +the slow motion (it is only comparatively slow) gives +the atmosphere a chance to refill the area disturbed by +one propeller blade, and thus have a new surface for +the next blade to act upon. + +Placing of the Motor. + +As on other points, aviators differ widely in their +ideas as to the proper position for the motor. Wright +locates his on the lower plane, midway between the front +and rear edges, but considerably to one side of the exact +center. He then counter-balances the engine weight by +placing his seat far enough away in the opposite direction +to preserve the center of gravity. This leaves a +space in the center between the motor and the operator +in which a passenger may be carried without disturbing +the equilibrium. + +Bleriot, on the contrary, has his motor directly in +front and preserves the center of gravity by taking his +seat well back, this, with the weight of the aeroplane, +acting as a counter-balance. + +On the Curtiss machine the motor is in the rear, the +forward seat of the operator, and weight of the horizontal +rudder and damping plane in front equalizing the +engine weight. + +No Perfect Motor as Yet. + +Engine makers in the United States, England, France +and Germany are all seeking to produce an ideal motor +for aviation purposes. Many of the productions are +highly creditable, but it may be truthfully said that +none of them quite fill the bill as regards a combination +of the minimum of weight with the maximum of +reliable maintained power. They are all, in some respects, +improvements upon those previously in use, but +the great end sought for has not been fully attained. + +One of the motors thus produced was made by the +French firm of Darracq at the suggestion of Santos Dumont, and on +lines laid down by him. Santos Dumont +wanted a 2-cylinder horizontal motor capable of developing +30 horsepower, and not exceeding 4 1/2 pounds per +horsepower in weight. + +There can be no question as to the ability and skill +of the Darracq people, or of their desire to produce a +motor that would bring new credit and prominence to +the firm. Neither could anything radically wrong be +detected in the plans. But the motor, in at least one +important requirement, fell short of expectations. + +It could not be depended upon to deliver an energy +of 30 horsepower continuously for any length of time. +Its maximum power could be secured only in "spurts." + +This tends to show how hard it is to produce an ideal +motor for aviation purposes. Santos Dumont, of undoubted +skill and experience as an aviator, outlined definitely +what he wanted; one of the greatest designers +in the business drew the plans, and the famous house of +Darracq bent its best energies to the production. But +the desired end was not fully attained. + +Features of Darracq Motor. + +Horizontal motors were practically abandoned some +time ago in favor of the vertical type, but Santos Dumont +had a logical reason for reverting to them. He +wanted to secure a lower center of gravity than would +be possible with a vertical engine. Theoretically his +idea was correct as the horizontal motor lies flat, and +therefore offers less resistance to the wind, but it did not +work out as desired. + +At the same time it must be admitted that this Darracq +motor is a marvel of ingenuity and exquisite workmanship. +The two cylinders, having a bore of 5 1-10 +inches and a stroke of 4 7-10 inches, are machined out +of a solid bar of steel until their weight is only 8 4-5 +pounds complete. The head is separate, carrying the +seatings for the inlet and exhaust valves, is screwed onto +the cylinder, and then welded in position. A copper +water-jacket is fitted, and it is in this condition that the +weight of 8 4-5 pounds is obtained. + +On long trips, especially in regions where gasolene is +hard to get, the weight of the fuel supply is an important +feature in aviation. As a natural consequence flying +machine operators favor the motor of greatest economy +in gasolene consumption, provided it gives the necessary +power. + +An American inventor, Ramsey by name, is working +on a motor which is said to possess great possibilities +in this line. Its distinctive features include a connecting +rod much shorter than usual, and a crank shaft located +the length of the crank from the central axis of the +cylinder. This has the effect of increasing the piston +stroke, and also of increasing the proportion of the +crank circle during which effective pressure is applied +to the crank. + +Making the connecting rod shorter and leaving the +crank mechanism the same would introduce excessive +cylinder friction. This Ramsey overcomes by the location +of his crank shaft. The effect of the long piston +stroke thus secured, is to increase the expansion of the +gases, which in turn increases the power of the engine +without increasing the amount of fuel used. + +Propeller Thrust Important. + +There is one great principle in flying machine propulsion +which must not be overlooked. No matter how +powerful the engine may be unless the propeller thrust +more than overcomes the wind pressure there can be +no progress forward. Should the force of this propeller +thrust and that of the wind pressure be equal the result +is obvious. The machine is at a stand-still so far +as forward progress is concerned and is deprived of the +essential advancing movement. + +Speed not only furnishes sustentation for the airship, +but adds to the stability of the machine. An aeroplane +which may be jerky and uncertain in its movements, so +far as equilibrium is concerned, when moving at a slow +gait, will readily maintain an even keel when the speed +is increased. + +Designs for Propeller Blades. + +It is the object of all men who design propellers to +obtain the maximum of thrust with the minimum expenditure +of engine energy. With this purpose in view +many peculiar forms of propeller blades have been +evolved. In theory it would seem that the best effects +could be secured with blades so shaped as to present a +thin (or cutting) edge when they come out of the wind, +and then at the climax of displacement afford a maximum +of surface so as to displace as much air as possible. +While this is the form most generally favored +there are others in successful operation. + +There is also wide difference in opinion as to the +equipment of the propeller shaft with two or more +blades. Some aviators use two and some four. All +have more or less success. As a mathematical proposition +it would seem that four blades should give more +propulsive force than two, but here again comes in one +of the puzzles of aviation, as this result is not always +obtained. + +Difference in Propeller Efficiency. + +That there is a great difference in propeller efficiency +is made readily apparent by the comparison of effects +produced in two leading makes of machines--the Wright +and the Voisin. + +In the former a weight of from 1,100 to 1,200 pounds +is sustained and advance progress made at the rate of +40 miles an hour and more, with half the engine speed +of a 25 horse-power motor. This would be a sustaining +capacity of 48 pounds per horsepower. But the actual +capacity of the Wright machine, as already stated, is 50 +pounds per horsepower. + +The Voisin machine, with aviator, weighs about 1,370 +pounds, and is operated with a so-horsepower motor. +Allowing it the same speed as the Wright we find that, +with double the engine energy, the lifting capacity is +only 27 1/2 pounds per horsepower. To what shall we +charge this remarkable difference? The surface of the +planes is exactly the same in both machines so there +is no advantage in the matter of supporting area. + +Comparison of Two Designs. + +On the Wright machine two wooden propellers of +two blades each (each blade having a decided "twist") +are used. As one 25 horsepower motor drives both propellers the +engine energy amounts to just one-half of +this for each, or 12 1/2 horsepower. And this energy is +utilized at one-half the normal engine speed. + +On the Voisin a radically different system is employed. +Here we have one metal two-bladed propeller with a +very slight "twist" to the blade surfaces. The full energy +of a 50-horsepower motor is utilized. + +Experts Fail to Agree. + +Why should there be such a marked difference in +the results obtained? Who knows? Some experts +maintain that it is because there are two propellers on +the Wright machine and only one on the Voisin, and +consequently double the propulsive power is exerted. +But this is not a fair deduction, unless both propellers +are of the same size. Propulsive power depends upon +the amount of air displaced, and the energy put into the +thrust which displaces the air. + +Other experts argue that the difference in results may +be traced to the difference in blade design, especially +in the matter of "twist." + +The fact is that propeller results depend largely upon +the nature of the aeroplanes on which they are used. +A propeller, for instance, which gives excellent results +on one type of aeroplane, will not work satisfactorily on +another. + +There are some features, however, which may be safely +adopted in propeller selection. These are: As extensive +a diameter as possible; blade area 10 to 15 per cent +of the area swept; pitch four-fifths of the diameter; +rotation slow. The maximum of thrust effort will be thus +obtained. + + + +CHAPTER X. + +PROPER DIMENSIONS OF MACHINES. + +In laying out plans for a flying machine the first thing +to decide upon is the size of the plane surfaces. The +proportions of these must be based upon the load to be +carried. This includes the total weight of the machine +and equipment, and also the operator. This will be a +rather difficult problem to figure out exactly, but +practical approximate figures may be reached. + +It is easy to get at the weight of the operator, motor +and propeller, but the matter of determining, before they +are constructed, what the planes, rudders, auxiliaries, +etc., will weigh when completed is an intricate proposition. +The best way is to take the dimensions of some +successful machine and use them, making such alterations +in a minor way as you may desire. + +Dimensions of Leading Machines. + +In the following tables will be found the details as to +surface area, weight, power, etc., of the nine principal +types of flying machines which are now prominently before +the public: + + MONOPLANES. + Surface area Spread in Depth in +Make Passengers sq. feet linear feet linear +feet +Santos-Dumont . . 1 110 16.0 26.0 +Bleriot . . . . . 1 150.6 24.6 22.0 +R. E. P . . . . . 1 215 34.1 28.9 +Bleriot . . . . . 2 236 32.9 23.0 +Antoinette. . . . 2 538 41.2 37.9 + No. of Weight Without +Propeller +Make Cylinders Horse Power Operator +Diameter +Santos-Dumont. . 2 30 250 5.0 +Bleriot. . . . . 3 25 680 6.9 +R. E. P. . . . . 7 35 900 6.6 +Bleriot. . . . . 7 50 1,240 8.1 +Antoinette . . . 8 50 1,040 7.2 + + BIPLANES. + Surface Area Spread in Depth +in +Make Passengers sq. feet linear feet linear +feet +Curtiss . . . 2 258 29.0 +28.7 +Wright. . . . 2 538 41.0 +30.7 +Farman. . . . 2 430 32.9 +39.6 +Voisin. . . . 2 538 37.9 +39.6 + + No. of Weight Without +Propeller +Make Cylinders Horse Power Operator +Diameter +Curtiss . . . 8 50 600 6.0 +Wright. . . . 4 25 1,100 8.1 +Farman. . . . 7 50 1,200 8.9 +Voisin. . . . 8 50 1,200 6.6 + +In giving the depth dimensions the length over all-- +from the extreme edge of the front auxiliary plane to +the extreme tip of the rear is stated. Thus while the +dimensions of the main planes of the Wright machine +are 41 feet spread by 6 1/2 feet in depth, the depth over +all is 30.7. + +Figuring Out the Details. + +With this data as a guide it should be comparatively +easy to decide upon the dimensions of the machine required. +In arriving at the maximum lifting capacity the +weight of the operator must be added. Assuming this +to average 170 pounds the method of procedure would be +as follows: + +Add the weight of the operator to the weight of the +complete machine. The new Wright machine complete +weighs 900 pounds. This, plus 170, the weight of the +operator, gives a total of 1,070 pounds. There are 538 +square feet of supporting surface, or practically one +square foot of surface area to each two pounds of load. + +There are some machines, notably the Bleriot, in which +the supporting power is much greater. In this latter +instance we find a surface area of 150 1/2 square feet +carrying a load of 680 plus 170, or an aggregate of 850 +pounds. This is the equivalent of five pounds to the +square foot. This ratio is phenomenally large, and +should not be taken as a guide by amateurs. + +The Matter of Passengers. + +These deductions are based on each machine carrying +one passenger, which is admittedly the limit at present +of the monoplanes like those operated for record-making +purposes by Santos-Dumont and Bleriot. The biplanes, +however, have a two-passenger capacity, and this adds +materially to the proportion of their weight-sustaining +power as compared with the surface area. In the following +statement all the machines are figured on the +one-passenger basis. Curtiss and Wright have carried +two passengers on numerous occasions, and an extra 170 +pounds should therefore be added to the total weight +carried, which would materially increase the capacity. +Even with the two-passenger load the limit is by no +means reached, but as experiments have gone no further +it is impossible to make more accurate figures. + +Average Proportions of Load. + +It will be interesting, before proceeding to lay out the +dimension details, to make a comparison of the proportion +of load effect with the supporting surfaces of various +well-known machines. Here are the figures: + +Santos-Dumont--A trifle under four pounds per square +foot. + +Bleriot--Five pounds. + +R. E. P.--Five pounds. + +Antoinette--About two and one-quarter pounds. + +Curtiss--About two and one-half pounds. + +Wright--Two and one-quarter pounds. + +Farman--A trifle over three pounds. + +Voisin--A little under two and one-half pounds. + +Importance of Engine Power. + +While these figures are authentic, they are in a way +misleading, as the important factor of engine power +is not taken into consideration. Let us recall the fact +that it is the engine power which keeps the machine in +motion, and that it is only while in motion that the machine +will remain suspended in the air. Hence, to attribute the support +solely to the surface area is erroneous. +True, that once under headway the planes contribute +largely to the sustaining effect, and are absolutely essential +in aerial navigation--the motor could not rise without +them--still, when it comes to a question of weight- +sustaining power, we must also figure on the engine +capacity. + +In the Wright machine, in which there is a lifting +capacity of approximately 2 1/4 pounds to the square foot +of surface area, an engine of only 25 horsepower is used. +In the Curtiss, which has a lifting capacity of 2 1/2 +pounds per square foot, the engine is of 50 horsepower. +This is another of the peculiarities of aerial construction +and navigation. Here we have a gain of 1/4 pound in +weight-lifting capacity with an expenditure of double +the horsepower. It is this feature which enables Curtiss +to get along with a smaller surface area of supporting +planes at the expense of a big increase in engine power. +Proper Weight of Machine. + +As a general proposition the most satisfactory machine +for amateur purposes will be found to be one with +a total weight-sustaining power of about 1,200 pounds. +Deducting 170 pounds as the weight of the operator, +this will leave 1,030 pounds for the complete motor- +equipped machine, and it should be easy to construct one +within this limit. This implies, of course, that due care +will be taken to eliminate all superfluous weight by using +the lightest material compatible with strength and safety. + +This plan will admit of 686 pounds weight in the +frame work, coverings, etc., and 344 for the motor, +propeller, etc., which will be ample. Just how to distribute +the weight of the planes is a matter which must +be left to the ingenuity of the builder. + +Comparison of Bird Power. + +There is an interesting study in the accompanying +illustration. Note that the surface area of the albatross +is much smaller than that of the vulture, although the +wing spread is about the same. Despite this the albatross +accomplishes fully as much in the way of flight +and soaring as the vulture. Why? Because the albaboss is quicker +and more powerful in action. It is +the application of this same principle in flying machines +which enables those of great speed and power to get +along with less supporting surface than those of slower +movement. + +Measurements of Curtiss Machine. + +Some idea of framework proportion may be had from +the following description of the Curtiss machine. The +main planes have a spread (width) of 29 feet, and are +4 1/2 feet deep. The front double surface horizontal rudder +is 6x2 feet, with an area of 24 square feet. To the +rear of the main planes is a single surface horizontal +plane 6x2 feet, with an area of 12 square feet. In connection +with this is a vertical rudder 2 1/2 feet square. +Two movable ailerons, or balancing planes, are placed +at the extreme ends of the upper planes. These are 6x2 +feet, and have a combined area of 24 square feet. There +is also a triangular shaped vertical steadying surface in +connection with the front rudder. + +Thus we have a total of 195 square feet, but as the +official figures are 258, and the size of the triangular- +shaped steadying surface is unknown, we must take it +for granted that this makes up the difference. In the +matter of proportion the horizontal double-plane rudder +is about one-tenth the size of the main plane, counting +the surface area of only one plane, the vertical rudder +one-fortieth, and the ailerons one-twentieth. + + + +CHAPTER XI. + +PLANE AND RUDDER CONTROL. + +Having constructed and equipped your machine, the +next thing is to decide upon the method of controlling +the various rudders and auxiliary planes by which the +direction and equilibrium and ascending and descending +of the machine are governed. + +The operator must be in position to shift instantaneously the +position of rudders and planes, and also to control +the action of the motor. This latter is supposed to +work automatically and as a general thing does so with +entire satisfaction, but there are times when the supply +of gasolene must be regulated, and similar things done. +Airship navigation calls for quick action, and for this +reason the matter of control is an important one--it is +more than important; it is vital. + +Several Methods of Control. + +Some aviators use a steering wheel somewhat after +the style of that used in automobiles, and by this not +only manipulate the rudder planes, but also the flow of +gasolene. Others employ foot levers, and still others, +like the Wrights, depend upon hand levers. + +Curtiss steers his aeroplane by means of a wheel, but +secures the desired stabilizing effect with an ingenious +jointed chair-back. This is so arranged that by leaning +toward the high point of his wing planes the aeroplane +is restored to an even keel. The steering post of the +wheel is movable backward and forward, and by this +motion elevation is obtained. + +The Wrights for some time used two hand levers, one +to steer by and warp the flexible tips of the planes, the +other to secure elevation. They have now consolidated +all the functions in one lever. Bleriot also uses the +single lever control. + +Farman employs a lever to actuate the rudders, but +manipulates the balancing planes by foot levers. + +Santos-Dumont uses two hand levers with which to +steer and elevate, but manipulates the planes by means +of an attachment to the back of his outer coat. + +Connection With the Levers. + +No matter which particular method is employed, the +connection between the levers and the object to be manipulated +is almost invariably by wire. For instance, from +the steering levers (or lever) two wires connect with opposite +sides of the rudder. As a lever is moved so as to +draw in the right-hand wire the rudder is drawn to the +right and vice versa. The operation is exactly the same +as in steering a boat. It is the same way in changing +the position of the balancing planes. A movement of +the hands or feet and the machine has changed its +course, or, if the equilibrium is threatened, is back on +an even keel. + +Simple as this seems it calls for a cool head, quick +eye, and steady hand. The least hesitation or a false +movement, and both aviator and craft are in danger. + +Which Method is Best? + +It would be a bold man who would attempt to pick +out any one of these methods of control and say it was +better than the others. As in other sections of aeroplane +mechanism each method has its advocates who dwell +learnedly upon its advantages, but the fact remains that +all the various plans work well and give satisfaction. + +What the novice is interested in knowing is how the +control is effected, and whether he has become proficient +enough in his manipulation of it to be absolutely dependable +in time of emergency. No amateur should attempt +a flight alone, until he has thoroughly mastered +the steering and plane control. If the services and advice of an +experienced aviator are not to be had the +novice should mount his machine on some suitable supports +so it will be well clear of the ground, and, getting +into the operator's seat, proceed to make himself well +acquainted with the operation of the steering wheel and +levers. + +Some Things to Be Learned. + +He will soon learn that certain movements of the +steering gear produce certain effects on the rudders. If, +for instance, his machine is equipped with a steering +wheel, he will find that turning the wheel to the right +turns the aeroplane in the same direction, because the +tiller is brought around to the left. In the same way +he will learn that a given movement of the lever throws +the forward edge of the main plane upward, and that the +machine, getting the impetus of the wind under the concave +surfaces of the planes, will ascend. In the same +way it will quickly become apparent to him that an opposite +movement of the lever will produce an opposite +effect--the forward edges of the planes will be lowered, +the air will be "spilled" out to the rear, and the machine +will descend. + +The time expended in these preliminary lessons will +be well spent. It would be an act of folly to attempt to +actually sail the craft without them. + + + +CHAPTER XII. + +HOW TO USE THE MACHINE. + +It is a mistaken idea that flying machines must be +operated at extreme altitudes. True, under the impetus +of handsome prizes, and the incentive to advance scientific +knowledge, professional aviators have ascended to +considerable heights, flights at from 500 to 1,500 feet being +now common with such experts as Farman, Bleriot, +Latham, Paulhan, Wright and Curtiss. The altitude +record at this time is about 4,165 feet, held by Paulhan. + +One of the instructions given by experienced aviators +to pupils, and for which they insist upon implicit obeyance, is: +"If your machine gets more than 30 feet high, +or comes closer to the ground than 6 feet, descend at +once." Such men as Wright and Curtiss will not tolerate +a violation of this rule. If their instructions are +not strictly complied with they decline to give the offender +further lessons. + +Why This Rule Prevails. + +There is good reason for this precaution. The higher +the altitude the more rarefied (thinner) becomes the air, +and the less sustaining power it has. Consequently the +more difficult it becomes to keep in suspension a given +weight. When sailing within 30 feet of the ground sustentation +is comparatively easy and, should a fall occur, +the results are not likely to be serious. On the other +hand, sailing too near the ground is almost as objectionable +in many ways as getting up too high. If the craft +is navigated too close to the ground trees, shrubs, fences +and other obstructions are liable to be encountered. +There is also the handicap of contrary air currents +diverted by the obstructions referred to, and which will +be explained more fully further on. + +How to Make a Start. + +Taking it for granted that the beginner has familiarized +himself with the manipulation of the machine, and especially +the control mechanism, the next thing in order +is an actual flight. It is probable that his machine will +be equipped with a wheeled alighting gear, as the skids +used by the Wrights necessitate the use of a special +starting track. In this respect the wheeled machine is +much easier to handle so far as novices are concerned +as it may be easily rolled to the trial grounds. This, +as in the case of the initial experiments, should be a +clear, reasonably level place, free from trees, fences, +rocks and similar obstructions with which there may be +danger of colliding. + +The beginner will need the assistance of three men. +One of these should take his position in the rear of the +machine, and one at each end. On reaching the trial +ground the aviator takes his seat in the machine and, +while the men at the ends hold it steady the one in the rear +assists in retaining it until the operator is ready. In the +meantime the aviator has started his motor. Like the +glider the flying machine, in order to accomplish the +desired results, should be headed into the wind. + +When the Machine Rises. + +Under the impulse of the pushing movement, and assisted +by the motor action, the machine will gradually +rise from the ground--provided it has been properly +proportioned and put together, and everything is in working +order. This is the time when the aviator requires +a cool head, At a modest distance from the ground use +the control lever to bring the machine on a horizontal +level and overcome the tendency to rise. The exact +manipulation of this lever depends upon the method of +control adopted, and with this the aviator is supposed +to have thoroughly familiarized himself as previously +advised in Chapter XI. + +It is at this juncture that the operator must act +promptly, but with the perfect composure begotten of +confidence. One of the great drawbacks in aviation by +novices is the tendency to become rattled, and this is +much more prevalent than one might suppose, even +among men who, under other conditions, are cool and +confident in their actions. + +There is something in the sensation of being suddenly +lifted from the ground, and suspended in the air that is +disconcerting at the start, but this will soon wear off if +the experimenter will keep cool. A few successful flights +no matter how short they may be, will put a lot of +confidence into him. + +Make Your Flights Short. + +Be modest in your initial flights. Don't attempt to +match the records of experienced men who have devoted +years to mastering the details of aviation. Paulhan, +Farman, Bleriot, Wright, Curtiss, and all the rest of +them began, and practiced for years, in the manner here +described, being content to make just a little advancement +at each attempt. A flight of 150 feet, cleanly and +safely made, is better as a beginning than one of 400 +yards full of bungling mishaps. + +And yet these latter have their uses, provided the +operator is of a discerning mind and can take advantage +of them as object lessons. But, it is not well to invite +them. They will occur frequently enough under the +most favorable conditions, and it is best to have them +come later when the feeling of trepidation and uncertainty +as to what to do has worn off. + +Above all, don't attempt to fly too high. Keep within +a reasonable distance from the ground--about 25 or 30 +feet. This advice is not given solely to lessen the risk +of serious accident in case of collapse, but mainly because +it will assist to instill confidence in the operator. + +It is comparatively easy to learn to swim in shallow +water, but the knowledge that one is tempting death in +deep water begets timidity. + +Preserving the Equilibrium. + +After learning how to start and stop, to ascend and +descend, the next thing to master is the art of preserving +equilibrium, the knack of keeping the machine perfectly +level in the air--on an "even keel," as a sailor would +say. This simile is particularly appropriate as all aviators +are in reality sailors, and much more daring ones +than those who course the seas. The latter are in craft +which are kept afloat by the buoyancy of the water, +whether in motion or otherwise and, so long as normal +conditions prevail, will not sink. Aviators sail the air +in craft in which constant motion must be maintained in +order to ensure flotation. + +The man who has ridden a bicycle or motorcycle +around curves at anything like high speed, will have a +very good idea as to the principle of maintaining equilibrium +in an airship. He knows that in rounding curves +rapidly there is a marked tendency to change the direction +of the motion which will result in an upset unless +he overcomes it by an inclination of his body in an opposite +direction. This is why we see racers lean well +over when taking the curves. It simply must be done +to preserve the equilibrium and avoid a spill. + +How It Works In the Air. + +If the equilibrium of an airship is disturbed to an +extent which completely overcomes the center of gravity +it falls according to the location of the displacement. +If this displacement, for instance, is at either end the +apparatus falls endways; if it is to the front or rear, the +fall is in the corresponding direction. + +Owing to uncertain air currents--the air is continually +shifting and eddying, especially within a hundred feet or +so of the earth--the equilibrium of an airship is almost +constantly being disturbed to some extent. Even if this +disturbance is not serious enough to bring on a fall it +interferes with the progress of the machine, and should +be overcome at once. This is one of the things connected +with aerial navigation which calls for prompt, +intelligent action. + +Frequently, when the displacement is very slight, it +may be overcome, and the craft immediately righted by +a mere shifting of the operator's body. Take, for illustration, +a case in which the extreme right end of the +machine becomes lowered a trifle from the normal level. +It is possible to bring it back into proper position by +leaning over to the left far enough to shift the weight +to the counter-balancing point. The same holds good as +to minor front or rear displacements. + +When Planes Must Be Used. + +There are other displacements, however, and these are +the most frequent, which can be only overcome by manipulation of +the stabilizing planes. The method of procedure +depends upon the form of machine in use. The +Wright machine, as previously explained, is equipped +with plane ends which are so contrived as to admit of +their being warped (position changed) by means of the +lever control. These flexible tip planes move simultaneously, +but in opposite directions. As those on one end +rise, those on the other end fall below the level of the +main plane. By this means air is displaced at one point, +and an increased amount secured in another. + +This may seem like a complicated system, but its +workings are simple when once understood. It is by +the manipulation or warping of these flexible tips that +transverse stability is maintained, and any tendency to +displacement endways is overcome. Longitudinal stability +is governed by means of the front rudder. + +Stabilizing planes of some form are a feature, and a +necessary feature, on all flying machines, but the methods +of application and manipulation vary according to the +individual ideas of the inventors. They all tend, however, +toward the same end--the keeping of the machine +perfectly level when being navigated in the air. + +When to Make a Flight. + +A beginner should never attempt to make a flight +when a strong wind is blowing. The fiercer the wind, +the more likely it is to be gusty and uncertain, and the +more difficult it will be to control the machine. Even +the most experienced and daring of aviators find there +is a limit to wind speed against which they dare not +compete. This is not because they lack courage, but +have the sense to realize that it would be silly and useless. + +The novice will find a comparatively still day, or one +when the wind is blowing at not to exceed 15 miles an +hour, the best for his experiments. The machine will be +more easily controlled, the trip will be safer, and also +cheaper as the consumption of fuel increases with the +speed of the wind against which the aeroplane is forced. + + + +CHAPTER XIII. + +PECULIARITIES OF AIRSHIP POWER. + +As a general proposition it takes much more power to +propel an airship a given number of miles in a certain +time than it does an automobile carrying a far heavier +load. Automobiles with a gross load of 4,000 pounds, +and equipped with engines of 30 horsepower, have travelled +considerable distances at the rate of 50 miles an +hour. This is an equivalent of about 134 pounds per +horsepower. For an average modern flying machine, +with a total load, machine and passengers, of 1,200 +pounds, and equipped with a 50-horsepower engine, 50 +miles an hour is the maximum. Here we have the equivalent +of exactly 24 pounds per horsepower. Why this +great difference? + +No less an authority than Mr. Octave Chanute answers +the question in a plain, easily understood manner. He +says: + +"In the case of an automobile the ground furnishes a +stable support; in the case of a flying machine the engine +must furnish the support and also velocity by which the +apparatus is sustained in the air." + +Pressure of the Wind. + +Air pressure is a big factor in the matter of aeroplane +horsepower. Allowing that a dead calm exists, a body +moving in the atmosphere creates more or less resistance. +The faster it moves, the greater is this resistance. +Moving at the rate of 60 miles an hour the resistance, +or wind pressure, is approximately 50 pounds to the +square foot of surface presented. If the moving object +is advancing at a right angle to the wind the following +table will give the horsepower effect of the resistance +per square foot of surface at various speeds. + + Horse Power +Miles per Hour per sq. foot +10 0.013 +15 0 044 +20 0.105 +25 0.205 +30 0.354 +40 0.84 +50 1.64 +60 2.83 +80 6.72 +100 13.12 + +While the pressure per square foot at 60 miles an hour, +is only 1.64 horsepower, at 100 miles, less than double +the speed, it has increased to 13.12 horsepower, or exactly +eight times as much. In other words the pressure +of the wind increases with the square of the velocity. +Wind at 10 miles an hour has four times more pressure +than wind at 5 miles an hour. + +How to Determine Upon Power. + +This element of air resistance must be taken into consideration +in determining the engine horsepower required. +When the machine is under headway sufficient +to raise it from the ground (about 20 miles an hour), +each square foot of surface resistance, will require nearly +nine-tenths of a horsepower to overcome the wind pressure, +and propel the machine through the air. As +shown in the table the ratio of power required increases +rapidly as the speed increases until at 60 miles an hour +approximately 3 horsepower is needed. + +In a machine like the Curtiss the area of wind-exposed +surface is about 15 square feet. On the basis of this +resistance moving the machine at 40 miles an hour would +require 12 horsepower. This computation covers only +the machine's power to overcome resistance. It does +not cover the power exerted in propelling the machine +forward after the air pressure is overcome. To meet +this important requirement Mr. Curtiss finds it necessary +to use a 50-horsepower engine. Of this power, as +has been already stated, 12 horsepower is consumed +in meeting the wind pressure, leaving 38 horsepower +for the purpose of making progress. + +The flying machine must move faster than the air to +which it is opposed. Unless it does this there can be no +direct progress. If the two forces are equal there is no +straight-ahead advancement. Take, for sake of illustration, +a case in which an aeroplane, which has developed a +speed of 30 miles an hour, meets a wind velocity of +equal force moving in an opposite direction. What is +the result? There can be no advance because it is a +contest between two evenly matched forces. The aeroplane +stands still. The only way to get out of the difficulty +is for the operator to wait for more favorable conditions, +or bring his machine to the ground in the usual +manner by manipulation of the control system. + +Take another case. An aeroplane, capable of making +50 miles an hour in a calm, is met by a head wind of 25 +miles an hour. How much progress does the aeroplane +make? Obviously it is 25 miles an hour over the ground. + +Put the proposition in still another way. If the wind +is blowing harder than it is possible for the engine power +to overcome, the machine will be forced backward. + +Wind Pressure a Necessity. + +While all this is true, the fact remains that wind +pressure, up to a certain stage, is an absolute necessity +in aerial navigation. The atmosphere itself has very +little real supporting power, especially if inactive. If +a body heavier than air is to remain afloat it must move +rapidly while in suspension. + +One of the best illustrations of this is to be found in +skating over thin ice. Every school boy knows that if +he moves with speed he may skate or glide in safety +across a thin sheet of ice that would not begin to bear +his weight if he were standing still. Exactly the same +proposition obtains in the case of the flying machine. + +The non-technical reason why the support of the machine +becomes easier as the speed increases is that the +sustaining power of the atmosphere increases with the +resistance, and the speed with which the object is moving +increases this resistance. With a velocity of 12 miles +an hour the weight of the machine is practically reduced +by 230 pounds. Thus, if under a condition of absolute +calm it were possible to sustain a weight of 770 pounds, +the same atmosphere would sustain a weight of 1,000 +pounds moving at a speed of 12 miles an hour. This +sustaining power increases rapidly as the speed increases. +While at 12 miles the sustaining power is figured at +230 pounds, at 24 miles it is four times as great, or 920 +pounds. + +Supporting Area of Birds. + +One of the things which all producing aviators seek +to copy is the motive power of birds, particularly in their +relation to the area of support. Close investigation has +established the fact that the larger the bird the less is +the relative area of support required to secure a given +result. This is shown in the following table: + + Supporting + Weight Surface Horse area +Bird in lbs. in sq. feet power per lb. +Pigeon 1.00 0.7 0.012 0.7 +Wild Goose 9.00 2.65 0.026 0.2833 +Buzzard 5.00 5.03 0.015 1.06 +Condor 17.00 9.85 0.043 0.57 + +So far as known the condor is the largest of modern +birds. It has a wing stretch of 10 feet from tip to tip, a +supporting area of about 10 square feet, and weighs 17 +pounds. It. is capable of exerting perhaps 1-30 horsepower. +(These figures are, of course, approximate.) +Comparing the condor with the buzzard with a wing +stretch of 6 feet, supporting area of 5 square feet, and a +little over 1-100 horsepower, it may be seen that, broadly +speaking, the larger the bird the less surface area (relatively) +is needed for its support in the air. + +Comparison With Aeroplanes. + +If we compare the bird figures with those made possible +by the development of the aeroplane it will be +readily seen that man has made a wonderful advance in +imitating the results produced by nature. Here are the +figures: + + Supporting + Weight Surface Horse area +Machine in lbs. in sq. feet power per lb. +Santos-Dumont . . 350 110.00 30 0.314 +Bleriot . . . . . 700 150.00 25 0.214 +Antoinette. . . . 1,200 538.00 50 0.448 +Curtiss . . . . . 700 258.00 60 0.368 +Wright. . . . .[4]1,100 538.00 25 0.489 +Farman. . . . . . 1,200 430.00 50 0.358 +Voisin. . . . . . 1,200 538.00 50 0.448 + +[4] The Wrights' new machine weighs only 900 pounds. + +While the average supporting surface is in favor of +the aeroplane, this is more than overbalanced by the +greater amount of horsepower required for the weight +lifted. The average supporting surface in birds is about +three-quarters of a square foot per pound. In the average +aeroplane it is about one-half square foot per pound. +On the other hand the average aeroplane has a lifting +capacity of 24 pounds per horsepower, while the buzzard, +for instance, lifts 5 pounds with 15-100 of a horsepower. +If the Wright machine--which has a lifting power of 50 +pounds per horsepower--should be alone considered the +showing would be much more favorable to the aeroplane, +but it would not be a fair comparison. + +More Surface, Less Power. + +Broadly speaking, the larger the supporting area the +less will be the power required. Wright, by the use of +538 square feet of supporting surface, gets along with an +engine of 25 horsepower. Curtiss, who uses only 258 +square feet of surface, finds an engine of 50 horsepower +is needed. Other things, such as frame, etc., being equal, +it stands to reason that a reduction in the area of +supporting surface will correspondingly reduce the weight +of the machine. Thus we have the Curtiss machine with +its 258 square feet of surface, weighing only 600 pounds +(without operator), but requiring double the horsepower +of the Wright machine with 538 square feet of surface +and weighing 1,100 pounds. This demonstrates in a +forceful way the proposition that the larger the surface +the less power will be needed. + +But there is a limit, on account of its bulk and +awkwardness in handling, beyond which the surface area +cannot be enlarged. Otherwise it might be possible to +equip and operate aeroplanes satisfactorily with engines +of 15 horsepower, or even less. + +The Fuel Consumption Problem. + +Fuel consumption is a prime factor in the production +of engine power. The veriest mechanical tyro knows in +a general way that the more power is secured the more +fuel must be consumed, allowing that there is no difference +in the power-producing qualities of the material +used. But few of us understand just what the ratio of +increase is, or how it is caused. This proposition is one +of keen interest in connection with aviation. + +Let us cite a problem which will illustrate the point +quoted: Allowing that it takes a given amount of gasolene +to propel a flying machine a given distance, half the +way with the wind, and half against it, the wind blowing +at one-half the speed of the machine, what will be +the increase in fuel consumption? + +Increase of Thirty Per Cent. + +On the face of it there would seem to be no call for +an increase as the resistance met when going against the +wind is apparently offset by the propulsive force of the +wind when the machine is travelling with it. This, however, +is called faulty reasoning. The increase in fuel +consumption, as figured by Mr. F. W. Lanchester, of the +Royal Society of Arts, will be fully 30 per cent over +the amount required for a similar operation of the machine +in still air. If the journey should be made at right +angles to the wind under the same conditions the increase +would be 15 per cent. + +In other words Mr. Lanchester maintains that the work +done by the motor in making headway against the wind +for a certain distance calls for more engine energy, and +consequently more fuel by 30 per cent, than is saved by +the helping force of the wind on the return journey. + + + +CHAPTER XIV. + +ABOUT WIND CURRENTS, ETC. + +One of the first difficulties which the novice will +encounter is the uncertainty of the wind currents. With a +low velocity the wind, some distance away from the +ground, is ordinarily steady. As the velocity increases, +however, the wind generally becomes gusty and fitful +in its action. This, it should be remembered, does not +refer to the velocity of the machine, but to that of the +air itself. + +In this connection Mr. Arthur T. Atherholt, president +of the Aero Club of Pennsylvania, in addressing the +Boston Society of Scientific Research, said: + +"Probably the whirlpools of Niagara contain no more +erratic currents than the strata of air which is now immediately +above us, a fact hard to realize on account +of its invisibility." + +Changes In Wind Currents. + +While Mr. Atherholt's experience has been mainly +with balloons it is all the more valuable on this account, +as the balloons were at the mercy of the wind and their +varying directions afforded an indisputable guide as to +the changing course of the air currents. In speaking of +this he said: + +"In the many trips taken, varying in distance traversed +from twenty-five to 900 miles, it was never possible +except in one instance to maintain a straight course. +These uncertain currents were most noticeable in the +Gordon-Bennett race from St. Louis in 1907. Of the +nine aerostats competing in that event, eight covered a +more or less direct course due east and southeast, whereas +the writer, with Major Henry B. Hersey, first started +northwest, then north, northeast, east, east by south, and +when over the center of Lake Erie were again blown +northwest notwithstanding that more favorable winds +were sought for at altitudes varying from 100 to 3,000 +meters, necessitating a finish in Canada nearly northeast +of the starting point. + +"These nine balloons, making landings extending from +Lake Ontario, Canada, to Virginia, all started from one +point within the same hour. + +"The single exception to these roving currents occurred +on October 21st, of last year (1909) when, starting +from Philadelphia, the wind shifted more than eight +degrees, the greatest variation being at the lowest altitudes, +yet at no time was a height of over a mile reached. + +"Throughout the entire day the sky was overcast, with +a thermometer varying from fifty-seven degrees at 300 +feet to forty-four degrees, Fahrenheit at 5,000 feet, at +which altitude the wind had a velocity of 43 miles an +hour, in clouds of a cirro-cumulus nature, a landing finally +being made near Tannersville, New York, in the +Catskill mountains, after a voyage of five and one-half +hours. + +"I have no knowledge of a recorded trip of this distance +and duration, maintained in practically a straight +line from start to finish." + +This wind disturbance is more noticeable and more +difficult to contend with in a balloon than in a flying +machine, owing to the bulk and unwieldy character of +the former. At the same time it is not conducive to +pleasant, safe or satisfactory sky-sailing in an aeroplane. +This is not stated with the purpose of discouraging +aviation, but merely that the operator may know what to +expect and be prepared to meet it. + +Not only does the wind change its horizontal course +abruptly and without notice, but it also shifts in a vertical +direction, one second blowing up, and another +down. No man has as yet fathomed the why and wherefore +of this erratic action; it is only known that it exists. + +The most stable currents will be found from 50 to 100 +feet from the earth, provided the wind is not diverted +by such objects as trees, rocks, etc. That there are +equally stable currents higher up is true, but they are +generally to be found at excessive altitudes. + +How a Bird Meets Currents. + +Observe a bird in action on a windy day and you will +find it continually changing the position of its wings. +This is done to meet the varying gusts and eddies of the +air so that sustentation may be maintained and headway +made. One second the bird is bending its wings, altering +the angle of incidence; the next it is lifting or depressing +one wing at a time. Still again it will extend +one wing tip in advance of the other, or be spreading or +folding, lowering or raising its tail. + +All these motions have a meaning, a purpose. They +assist the bird in preserving its equilibrium. Without +them the bird would be just as helpless in the air as a +human being and could not remain afloat. + +When the wind is still, or comparatively so, a bird, +having secured the desired altitude by flight at an angle, +may sail or soar with no wing action beyond an occasional +stroke when it desires to advance. But, in a +gusty, uncertain wind it must use its wings or alight +somewhere. + +Trying to Imitate the Bird. + +Writing in _Fly_, Mr. William E. White says: + +"The bird's flight suggests a number of ways in which +the equilibrium of a mechanical bird may be controlled. +Each of these methods of control may be effected by +several different forms of mechanism. + +"Placing the two wings of an aeroplane at an angle of +three to five degrees to each other is perhaps the oldest +way of securing lateral balance. This way readily occurs +to anyone who watches a sea gull soaring. The +theory of the dihedral angle is that when one wing is +lifted by a gust of wind, the air is spilled from under it; +while the other wing, being correspondingly depressed, +presents a greater resistance to the gust and is lifted +restoring the balance. A fixed angle of three to five degrees, +however, will only be sufficient for very light puffs +of wind and to mount the wings so that the whole wing +may be moved to change the dihedral angle presents +mechanical difficulties which would be better avoided. + +"The objection of mechanical impracticability applies +to any plan to preserve the balance by shifting weight +or ballast. The center of gravity should be lower than +the center of the supporting surfaces, but cannot be +made much lower. It is a common mistake to assume +that complete stability will be secured by hanging the +center of gravity very low on the principle of the +parachute. An aeroplane depends upon rapid horizontal motion for +its support, and if the center of gravity be far +below the center of support, every change of speed or +wind pressure will cause the machine to turn about its +center of gravity, pitching forward and backward dangerously. + +Preserving Longitudinal Balance. + +"The birds maintain longitudinal, or fore and aft balance, +by elevating or depressing their tails. Whether +this action is secured in an aeroplane by means of a +horizontal rudder placed in the rear, or by deflecting +planes placed in front of the main planes, the principle +is evidently the same. A horizontal rudder placed well +to the rear as in the Antoinette, Bleriot or Santos-Dumont +monoplanes, will be very much safer and steadier +than the deflecting planes in front, as in the Wright or +Curtiss biplanes, but not so sensitive or prompt in action. + +"The natural fore and aft stability is very much +strengthened by placing the load well forward. The +center of gravity near the front and a tail or rudder +streaming to the rear secures stability as an arrow is +balanced by the head and feathering. The adoption of +this principle makes it almost impossible for the aeroplane +to turn over. + +The Matter of Lateral Balance. + +"All successful aeroplanes thus far have maintained +lateral balance by the principle of changing the angle +of incidence of the wings. + +"Other ways of maintaining the lateral balance, suggested +by observation of the flight of birds are--extending +the wing tips and spilling the air through the pinions; +or, what is the same thing, varying the area of the +wings at their extremities. + +"Extending the wing tips seems to be a simple and +effective solution of the problem. The tips may be made +to swing outward upon a vertical axis placed at the front +edge of the main planes; or they may be hinged to the +ends of the main plane so as to be elevated or depressed +through suitable connections by the aviator; or they may +be supported from a horizontal axis parallel with the +ends of the main planes so that they may swing outward, +the aviator controlling both tips through one lever +so that as one tip is extended the other is retracted. + +"The elastic wing pinions of a bird bend easily before +the wind, permitting the gusts to glance off, but presenting +always an even and efficient curvature to the +steady currents of the air." + +High Winds Threaten Stability. + +To ensure perfect stability, without control, either human +or automatic, it is asserted that the aeroplane must +move faster than the wind is blowing. So long as the +wind is blowing at the rate of 30 miles an hour, and the +machine is traveling 40 or more, there will be little trouble +as regards equilibrium so far as wind disturbance +goes, provided the wind blows evenly and does not come +in gusts or eddying currents. But when conditions are +reversed--when the machine travels only 30 miles an +hour and the wind blows at the rate of 50, look out for +loss of equilibrium. + +One of the main reasons for this is that high winds +are rarely steady; they seldom blow for any length of +time at the same speed. They are usually "gusty," the +gusts being a momentary movement at a higher speed. +Tornadic gusts are also formed by the meeting of two +opposing currents, causing a whirling motion, which +makes stability uncertain. Besides, it is not unusual +for wind of high speed to suddenly change its direction +without warning. + +Trouble With Vertical Columns. + +Vertical currents--columns of ascending air--are +frequently encountered in unexpected places and have more +or less tendency, according to their strength, to make +it difficult to keep the machine within a reasonable +distance from the ground. + +These vertical currents are most generally noticeable +in the vicinity of steep cliffs, or deep ravines. In such +instances they are usually of considerable strength, being +caused by the deflection of strong winds blowing +against the face of the cliffs. This deflection exerts a +back pressure which is felt quite a distance away from +the point of origin, so that the vertical current exerts an +influence in forcing the machine upward long before the +cliff is reached. + + + +CHAPTER XV. + +THE ELEMENT OF DANGER. + +That there is an element of danger in aviation is +undeniable, but it is nowhere so great as the public +imagines. Men are killed and injured in the operation +of flying machines just as they are killed and injured in +the operation of railways. Considering the character of +aviation the percentage of casualties is surprisingly +small. + +This is because the results following a collapse in the +air are very much different from what might be imagined. +Instead of dropping to the ground like a bullet an +aeroplane, under ordinary conditions will, when anything +goes wrong, sail gently downward like a parachute, +particularly if the operator is cool-headed and nervy enough +to so manipulate the apparatus as to preserve its equilibrium +and keep the machine on an even keel. + +Two Fields of Safety. + +At least one prominent aviator has declared that there +are two fields of safety--one close to the ground, and +the other well up in the air. In the first-named the fall +will be a slight one with little chance of the operator +being seriously hurt. From the field of high altitude the +the descent will be gradual, as a rule, the planes of the +machine serving to break the force of the fall. With a +cool-headed operator in control the aeroplane may be +even guided at an angle (about 1 to 8) in its descent so +as to touch the ground with a gliding motion and with +a minimum of impact. + +Such an experience, of course, is far from pleasant, +but it is by no means so dangerous as might appear. +There is more real danger in falling from an elevation +of 75 or 100 feet than there is from 1,000 feet, as in the +former case there is no chance for the machine to serve as +a parachute--its contact with the ground comes too +quickly. + +Lesson in Recent Accidents. + +Among the more recent fatalities in aviation are the +deaths of Antonio Fernandez and Leon Delagrange. The +former was thrown to the ground by a sudden stoppage +of his motor, the entire machine seeming to collapse. +It is evident there were radical defects, not only in the +motor, but in the aeroplane framework as well. At the +time of the stoppage it is estimated that Fernandez was +up about 1,500 feet, but the machine got no opportunity +to exert a parachute effect, as it broke up immediately. +This would indicate a fatal weakness in the structure +which, under proper testing, could probably have been +detected before it was used in flight. + +It is hard to say it, but Delagrange appears to have +been culpable to great degree in overloading his machine +with a motor equipment much heavier than it was +designed to sustain. He was 65 feet up in the air when +the collapse occurred, resulting in his death. As in the +case of Fernandez common-sense precaution would +doubtless have prevented the fatality. + +Aviation Not Extra Hazardous. + +All told there have been, up to the time of this writing +(April, 1910), just five fatalities in the history of power- +driven aviation. This is surprisingly low when the nature +of the experiments, and the fact that most of the +operators were far from having extended experience, is +taken into consideration. Men like the Wrights, Curtiss, +Bleriot, Farman, Paulhan and others, are now experts, +but there was a time, and it was not long ago, when they +were unskilled. That they, with numerous others less +widely known, should have come safely through their +many experiments would seem to disprove the prevailing +idea that aviation is an extra hazardous pursuit. + +In the hands of careful, quick-witted, nervy men the +sailing of an airship should be no more hazardous than +the sailing of a yacht. A vessel captain with common +sense will not go to sea in a storm, or navigate a weak, +unseaworthy craft. Neither should an aviator attempt +to sail when the wind is high and gusty, nor with a machine +which has not been thoroughly tested and found to +be strong and safe. + +Safer Than Railroading. + +Statistics show that some 12,000 people are killed and +72,000 injured every year on the railroads of the United +States. Come to think it over it is small wonder that +the list of fatalities is so large. Trains are run at high +speeds, dashing over crossings at which collisions are +liable to occur, and over bridges which often collapse +or are swept away by floods. Still, while the number of +casualties is large, the actual percentage is small considering +the immense number of people involved. + +It is so in aviation. The number of casualties is remarkably +small in comparison with the number of flights +made. In the hands of competent men the sailing of an +airship should be, and is, freer from risk of accident than +the running of a railway train. There are no rails to +spread or break, no bridges to collapse, no crossings at +which collisions may occur, no chance for some sleepy +or overworked employee to misunderstand the dispatcher's +orders and cause a wreck. + +Two Main Causes of Trouble. + +The two main causes of trouble in an airship leading +to disaster may be attributed to the stoppage of the +motor, and the aviator becoming rattled so that he loses +control of his machine. Modern ingenuity is fast developing +motors that almost daily become more and more +reliable, and experience is making aviators more and +more self-confident in their ability to act wisely and +promptly in cases of emergency. Besides this a satisfactory +system of automatic control is in a fair way +of being perfected. + +Occasionally even the most experienced and competent +of men in all callings become careless and by foolish +action invite disaster. This is true of aviators the same +as it is of railroaders, men who work in dynamite mills, +etc. But in nearly every instance the responsibility rests +with the individual; not with the system. There are +some men unfitted by nature for aviation, just as there +are others unfitted to be railway engineers. + + + +CHAPTER XVI. + +RADICAL CHANGES BEING MADE. + +Changes, many of them extremely radical in their nature, +are continually being made by prominent aviators, +and particularly those who have won the greatest amount +of success. Wonderful as the results have been few of +the aviators are really satisfied. Their successes have +merely spurred them on to new endeavors, the ultimate +end being the development of an absolutely perfect aircraft. + +Among the men who have been thus experimenting +are the Wright Brothers, who last year (1909) brought +out a craft totally different as regards proportions and +weight from the one used the preceding year. One +marked result was a gain of about 3 1/2 miles an hour in +speed. + +Dimensions of 1908 Machine. + +The 1908 model aeroplane was 40 by 29 feet over all. +The carrying surfaces, that is, the two aerocurves, were +40 by 6 feet, having a parabolical curve of one in twelve. +With about 70 square feet of surface in the rudders, the +total surface given was about 550 square feet. The +engine, which is the invention of the Wright brothers, +weighed, approximately, 200 pounds, and gave about 25 +horsepower at 1,400 revolutions per minute. The total +weight of the aeroplane, exclusive of passenger, but +inclusive of engine, was about 1,150 pounds. This result +showed a lift of a fraction over 2 1/4 pounds to the square +foot of carrying surface. The speed desired was 40 +miles an hour, but the machine was found to make only +a scant 39 miles an hour. The upright struts were +about 7/8-inch thick, the skids, 2 1/2 by 1 1/4 inches thick. + +Dimensions of 1909 Machine. + +The 1909 aeroplane was built primarily for greater +speed, and relatively heavier; to be less at the mercy +of the wind. This result was obtained as follows: The +aerocurves, or carrying surfaces, were reduced in dimensions +from 40 by 6 feet to 36 by 5 1/2 feet, the curve +remaining the same, one in twelve. The upright struts +were cut from seven-eighths inch to five-eighths inch, and +the skids from two and one-half by one and one-quarter +to two and one-quarter by one and three-eighths inches. +This result shows that there were some 81 square feet +of carrying surface missing over that of last year's +model. and some 25 pounds loss of weight. Relatively, +though, the 1909 model aeroplane, while actually 25 +pounds lighter, is really some 150 pounds heavier in the +air than the 1908 model, owing to the lesser square +feet of carrying surface. + +Some of the Results Obtained. + +Reducing the carrying surfaces from 6 to 5 1/2 feet +gave two results--first, less carrying capacity; and, second, +less head-on resistance, owing to the fact that the +extent of the parabolic curve in the carrying surfaces +was shortened. The "head-on" resistance is the retardance +the aeroplane meets in passing through the air, +and is counted in square feet. In the 1908 model the +curve being one in twelve and 6 feet deep, gave 6 inches +of head-on resistance. The plane being 40 feet spread, +gave 6 inches by 40 feet, or 20 square feet of head-on +resistance. Increasing this figure by a like amount for +each plane, and adding approximately 10 square feet for +struts, skids and wiring, we have a total of approximately, +50 square feet of surface for "head-on" resistance. + +In the 1909 aeroplane, shortening the curve 6 inches +at the parabolic end of the curve took off 1 inch of +head-on resistance. Shortening the spread of the planes +took off between 3 and 4 square feet of head-on resistance. +Add to this the total of 7 square feet, less curve +surface and about 1 square foot, less wire and woodwork +resistance, and we have a grand total of, approximately, +12 square feet of less "head-on" resistance over +the 1908 model. + +Changes in Engine Action. + +The engine used in 1909 was the same one used in +1908, though some minor changes were made as +improvements; for instance, a make and break spark was +used, and a nine-tooth, instead of a ten-tooth magneto +gear-wheel was used. This increased the engine revolutions +per minute from 1,200 to 1,400, and the propeller +revolutions per minute from 350 to 371, giving a propeller +thrust of, approximately, 170 foot pounds instead +of 153, as was had last year. + +More Speed and Same Capacity. + +One unsatisfactory feature of the 1909 model over +that of 1908, apparently, was the lack of inherent lateral +stability. This was caused by the lesser surface and +lesser extent of curvatures at the portions of the +aeroplane which were warped. This defect did not show so +plainly after Mr. Orville Wright had become fully +proficient in the handling of the new machine, and with +skillful management, the 1909 model aeroplane will be +just as safe and secure as the other though it will take +a little more practice to get that same degree of skill. + +To sum up: The aeroplane used in 1909 was 25 +pounds lighter, but really about 150 pounds heavier in +the air, had less head-on resistance, and greater +propeller thrust. The speed was increased from about 39 +miles per hour to 42 1/2 miles per hour. The lifting +capacity remained about the same, about 450 pounds +capacity passenger-weight, with the 1908 machine. In this +respect, the loss of carrying surface was compensated for +by the increased speed. + +During the first few flights it was plainly demonstrated +that it would need the highest skill to properly +handle the aeroplane, as first one end and then the other +would dip and strike the ground, and either tear the canvas +or slew the aeroplane around and break a skid. + +Wrights Adopt Wheeled Gears. + +In still another important respect the Wrights, so far +as the output of one of their companies goes, have made +a radical change. All the aeroplanes turned out by the +Deutsch Wright Gesellschaft, according to the German +publication, _Automobil-Welt_, will hereafter be equipped +with wheeled running gears and tails. The plan of this +new machine is shown in the illustration on page 145. +The wheels are three in number, and are attached one +to each of the two skids, just under the front edge of +the planes, and one forward of these, attached to a cross- +member. It is asserted that with these wheels the +teaching of purchasers to operate the machines is much +simplified, as the beginners can make short flights on +their own account without using the starting derrick. + +This is a big concession for the Wrights to make, as +they have hitherto adhered stoutly to the skid gear. +While it is true they do not control the German company +producing their aeroplanes, yet the nature of their +connection with the enterprise is such that it may be +taken for granted no radical changes in construction +would be made without their approval and consent. + +Only Three Dangerous Rivals. + +Official trials with the 1909 model smashed many records +and leave the Wright brothers with only three dangerous +rivals in the field, and with basic patents which +cover the curve, warp and wing-tip devices found on +all the other makes of aeroplanes. These three rivals +are the Curtiss and Voisin biplane type and the Bleriot +monoplane pattern. + +The Bleriot monoplane is probably the most dangerous +rival, as this make of machine has a record of 54 +miles per hour, has crossed the English channel, and +has lifted two passengers besides the operator. The latest type +of this machine only weighs 771.61 pounds complete, +without passengers, and will lift a total passenger +weight of 462.97 pounds, which is a lift of 5.21 pounds +to the square foot. This is a better result than those +published by the Wright brothers, the best noted being +4.25 pounds per square foot. + +Other Aviators at Work. + +The Wrights, however, are not alone in their efforts +to promote the efficiency of the flying machine. Other +competent inventive aviators, notably Curtiss, Voisin, +Bleriot and Farman, are close after them. The Wrights, +as stated, have a marked advantage in the possession of +patents covering surface plane devices which have thus +far been found indispensable in flying machine construction. +Numerous law suits growing out of alleged infringements +of these patents have been started, and +others are threatened. What effect these actions will +have in deterring aviators in general from proceeding +with their experiments remains to be seen. + +In the meantime the four men named--Curtiss, Voisin, +Bleriot and Farman--are going ahead regardless of +consequences, and the inventive genius of each is so strong +that it is reasonable to expect some remarkable developments +in the near future. + +Smallest of Flying Machines. + +To Santos Dumont must be given the credit of producing +the smallest practical flying machine yet constructed. +True, he has done nothing remarkable with it +in the line of speed, but he has demonstrated the fact +that a large supporting surface is not an essential feature. + +This machine is named "La Demoiselle." It is a monoplane +of the dihedral type, with a main plane on each +side of the center. These main planes are of 18 foot +spread, and nearly 6 1/2 feet in depth, giving approximately +115 feet of surface area. The total weight is 242 pounds, +which is 358 pounds less than any other machine which +has been successfully used. The total depth from front +to rear is 26 feet. + +The framework is of bamboo, strengthened and held +taut with wire guys. + +Have One Rule in Mind. + +In this struggle for mastery in flying machine efficiency +all the contestants keep one rule in mind, and this +is: + +"The carrying capacity of an aeroplane is governed +by the peripheral curve of its carrying surfaces, plus the +speed; and the speed is governed by the thrust of the +propellers, less the 'head-on' resistance." + +Their ideas as to the proper means of approaching +the proposition may, and undoubtedly are, at variance, +but the one rule in solving the problem of obtaining the +greatest carrying capacity combined with the greatest +speed, obtains in all instances. + + + +CHAPTER XVII. + +SOME OF THE NEW DESIGNS. + +Spurred on by the success attained by the more experienced +and better known aviators numerous inventors +of lesser fame are almost daily producing practical flying +machines varying radically in construction from +those now in general use. + +One of these comparatively new designs is the Van +Anden biplane, made by Frank Van Anden of Islip, +Long Island, a member of the New York Aeronautic +Society. While his machine is wholly experimental, +many successful short flights were made with it last fall +(1909). One flight, made October 19th, 1909, is of particular +interest as showing the practicability of an automatic +stabilizing device installed by the inventor. The +machine was caught in a sudden severe gust of wind +and keeled over, but almost immediately righted itself, +thus demonstrating in a most satisfactory manner the +value of one new attachment. + +Features of Van Anden Model. + +In size the surfaces of the main biplane are 26 feet +in spread, and 4 feet in depth from front to rear. The +upper and lower planes are 4 feet apart. Silkolene +coated with varnish is used for the coverings. Ribs +(spruce) are curved one inch to the foot, the deepest +part of the curve (4 inches) being one foot back from the +front edge of the horizontal beam. Struts (also of +spruce, as is all the framework) are elliptical in shape. +The main beams are in three sections, nearly half round +in form, and joined by metal sleeves. + +There is a two-surface horizontal rudder, 2x2x4 feet, +in front. This is pivoted at its lateral center 8 feet from +the front edge of the main planes. In the rear is another +two-surface horizontal rudder 2x2x2 1/2 feet, pivoted +in the same manner as the front one, 15 feet from the +rear edges of the main planes. + +Hinged to the rear central strut of the rear rudder +is a vertical rudder 2 feet high by 3 feet in length. + +The Method of Control. + +In the operation of these rudders--both front and rear +--and the elevation and depression of the main planes, +the Curtiss system is employed. Pushing the steering- +wheel post outward depresses the front edges of the +planes, and brings the machine downward; pulling the +steering-wheel post inward elevates the front edges of +the planes and causes the machine to ascend. + +Turning the steering wheel itself to the right swings +the tail rudder to the left, and the machine, obeying this +like a boat, turns in the same direction as the wheel +is turned. By like cause turning the wheel to the left +turns the machine to the left. + +Automatic Control of Wings. + +There are two wing tips, each of 6 feet spread (length) +and 2 feet from front to rear. These are hinged half +way between the main surfaces to the two outermost +rear struts. Cables run from these to an automatic +device working with power from the engine, which automatically +operates the tips with the tilting of the +machine. Normally the wing tips are held horizontal +by stiff springs introduced in the cables outside of the +device. + +It was the successful working of this device which +righted the Van Anden craft when it was overturned in +the squall of October 19th, 1909. Previous to that +occurrence Mr. Van Anden had looked upon the device +as purely experimental, and had admitted that he had +grave uncertainty as to how it would operate in time of +emergency. He is now quoted as being thoroughly satisfied +with its practicability. It is this automatic device +which gives the Van Anden machine at least one distinctively +new feature. + +While on this subject it will not be amiss to add that +Mr. Curtiss does not look kindly on automatic control. +"I would rather trust to my own action than that of a +machine," he says. This is undoubtedly good logic so +far as Mr. Curtiss is concerned, but all aviators are not +so cool-headed and resourceful. + +Motive Power of Van Anden. + +A 50-horsepower "H-F" water cooled motor drives a +laminated wood propeller 6 feet in diameter, with a 17 +degree pitch at the extremities, increasing toward the +hub. The rear end of the motor is about 6 inches back +from the rear transverse beam and the engine shaft is +in a direct line with the axes of the two horizontal rudders. +An R. I. V. ball bearing carries the shaft at this +point. Flying, the motor turns at about 800 revolutions +per minute, delivering 180 pounds pull. A test of the +motor running at 1,200 showed a pull of 250 pounds on +the scales. + +Still Another New Aeroplane. + +Another new aeroplane is that produced by A. M. +Herring (an old-timer) and W. S. Burgess, under the +name of the Herring-Burgess. This is also equipped +with an automatic stability device for maintaining the +balance transversely. The curvature of the planes is +also laid out on new lines. That this new plan is +effective is evidenced by the fact that the machine has +been elevated to an altitude of 40 feet by using one-half +the power of the 30-horsepower motor. + +The system of rudder and elevation control is very +simple. The aviator sits in front of the lower plane, +and extending his arms, grasps two supports which extend +down diagonally in front. On the under side of +these supports just beneath his fingers are the controls +which operate the vertical rudder, in the rear. Thus, if +he wishes to turn to the right, he presses the control +under the fingers of his right hand; if to the left, that +under the fingers of his left hand. The elevating rudder +is operated by the aviator's right foot, the control +being placed on a foot-rest. + +Motor Is Extremely Light. + +Not the least notable feature of the craft is its motor. +Although developing, under load, 30-horsepower, or that +of an ordinary automobile, it weighs, complete, hardly +100 pounds. Having occasion to move it a little distance +for inspection, Mr. Burgess picked it up and walked +off with it--cylinders, pistons, crankcase and all, even +the magneto, being attached. There are not many 30- +horsepower engines which can be so handled. Everything +about it is reduced to its lowest terms of simplicity, +and hence, of weight. A single camshaft operates +not only all of the inlet and exhaust valves, but the magneto +and gear water pump, as well. The motor is placed +directly behind the operator, and the propeller is directly +mounted on the crankshaft. + +This weight of less than 100 pounds, it must be +remembered, is not for the motor alone; it includes the +entire power plant equipment. + +The "thrust" of the propeller is also extraordinary, +being between 250 and 260 pounds. The force of the +wind displacement is strong enough to knock down a +good-sized boy as one youngster ascertained when he +got behind the propeller as it was being tested. He +was not only knocked down but driven for some distance +away from the machine. The propeller has four +blades which are but little wider than a lath. + +Machine Built by Students. + +Students at the University of Pennsylvania, headed by +Laurence J. Lesh, a protege of Octave Chanute, have +constructed a practical aeroplane of ordinary maximum +size, in which is incorporated many new ideas. The +most unique of these is to be found in the steering gear, +and the provision made for the accommodation of a +pupil while taking lessons under an experienced aviator. + +Immediately back of the aviator is an extra seat and +an extra steering wheel which works in tandem style +with the front wheel. By this arrangement a beginner +may be easily and quickly taught to have perfect control +of the machine. These tandem wheels are also +handy for passengers who may wish to operate the car +independently of one another, it being understood, of +course, that there will be no conflict of action. + +Frame Size and Engine Power. + +The frame has 36 feet spread and measures 35 feet +from the front edge to the end of the tail in the rear. It +is equipped with two rear propellers operated by a Ramsey +8-cylinder motor of 50 horsepower, placed horizontally +across the lower plane, with the crank shaft running +clear through the engine. + +The "Pennsylvania I" is the first two-propeller biplane +chainless car, this scheme having been adopted in order +to avoid the crossing of chains. The lateral control is +by a new invention by Octave Chanute and Laurence J. +Lesh, for which Lesh is now applying for a patent. The +device was worked out before the Wright brothers' suit +was begun, and is said to be superior to the Wright +warping or the Curtiss ailerons. The landing device is +also new in design. This aeroplane will weigh about +1,500 pounds, and will carry fuel for a flight of 150 miles, +and it is expected to attain a speed of at least 45 miles +an hour. + +There are others, lots of them, too numerous in fact +to admit of mention in a book of this size. + + + +CHAPTER XVIII. + +DEMAND FOR FLYING MACHINES. + +As a commercial proposition the manufacture and sale +of motor-equipped aeroplanes is making much more +rapid advance than at first obtained in the similar +handling of the automobile. Great, and even phenomenal, +as was the commercial development of the motor +car, that of the flying machine is even greater. This is +a startling statement, but it is fully warranted by the +facts. + +It is barely more than a year ago (1909) that attention +was seriously attracted to the motor-equipped aeroplane +as a vehicle possible of manipulation by others +than professional aviators. Up to that time such actual +flights as were made were almost exclusively with the +sole purpose of demonstrating the practicability of the +machine, and the merits of the ideas as to shape, engine +power, etc., of the various producers. + +Results of Bleriot's Daring. + +It was not until Bleriot flew across the straits of +Dover on July 25th, 1909, that the general public awoke +to a full realization of the fact that it was possible for +others than professional aviators to indulge in aviation. +Bleriot's feat was accepted as proof that at last an +absolutely new means of sport, pleasure and research, +had been practically developed, and was within the +reach of all who had the inclination, nerve and financial +means to adopt it. + +From this event may be dated the birth of the modern +flying machine into the world of business. The automobile +was taken up by the general public from the +very start because it was a proposition comparatively +easy of demonstration. There was nothing mysterious +or uncanny in the fact that a wheeled vehicle could be +propelled on solid, substantial roads by means of engine +power. And yet it took (comparatively speaking) a long +time to really popularize the motor car. + +Wonderful Results in a Year. + +Men of large financial means engaged in the manufacture +of automobiles, and expended fortunes in attracting +public attention to them through the medium of +advertisements, speed and road contests, etc. By these +means a mammoth business has been built up, but bringing +this business to its present proportions required +years of patient industry and indomitable pluck. + +At this writing, less than a year from the day when +Bleriot crossed the channel, the actual sales of flying +machines outnumber the actual sales of automobiles in +the first year of their commercial development. This +may appear incredible, but it is a fact as statistics will +show. + +In this connection we should take into consideration +the fact that up to a year ago there was no serious intention +of putting flying machines on the market; no +preparations had been made to produce them on a commercial +scale; no money had been expended in advertisements +with a view to selling them. + +Some of the Actual Results. + +Today flying machines are being produced on a commercial +basis, and there is a big demand for them. The +people making them are overcrowded with orders. Some +of the producers are already making arrangements to +enlarge their plants and advertise their product for sale +the same as is being done with automobiles, while a +number of flying machine motor makers are already +promoting the sale of their wares in this way. + +Here are a few actual figures of flying machine sales +made by the more prominent producers since July 25th, +1909. + +Santos Dumont, 90 machines; Bleriot, 200; Farman, +130; Clemenceau-Wright, 80; Voisin, 100; Antoinette, +100. Many of these orders have been filled by delivery +of the machines, and in others the construction work +is under way. + +The foregoing are all of foreign make. In this country +Curtiss and the Wrights are engaged in similar +work, but no actual figures of their output are obtainable. + +Larger Plants Are Necessary. + +And this situation exists despite the fact that none of +the producers are really equipped with adequate plants +for turning out their machines on a modern, business- +like basis. The demand was so sudden and unexpected +that it found them poorly prepared to meet it. This, +however, is now being remedied by the erection of special +plants, the enlargement of others, and the introduction +of new machinery and other labor-saving conveniences. + +Companies, with large capitalization, to engage in the +exclusive production of airships are being organized in +many parts of the world. One notable instance of this +nature is worth quoting as illustrative of the manner +in which the production of flying machines is being +commercialized. This is the formation at Frankfort, +Germany, of the Flugmaschine Wright, G. m. b. H., with +a capital of $119,000, the Krupps, of Essen, being interested. + +Prices at Which Machines Sell. + +This wonderful demand from the public has come +notwithstanding the fact that the machines, owing to lack +of facilities for wholesale production, are far from being +cheap. Such definite quotations as are made are +on the following basis: + +Santos Dumont--List price $1,000, but owing to the +rush of orders agents are readily getting from $1,300 to +$1,500. This is the smallest machine made. + +Bleriot--List price $2,500. This is for the cross- +channel type, with Anzani motor. + +Antoinette--List price from $4,000 to $5,000, according +to size. + +Wright--List price $5,600. + +Curtiss--List price $5,000. + +There is, however, no stability in prices as purchasers +are almost invariably ready to pay a considerable premium +to facilitate delivery. + +The motor is the most expensive part of the flying +machine. Motor prices range from $500 to $2,000, this +latter amount being asked for the Curtiss engine. + +Systematic Instruction of Amateurs. + +In addition to the production of flying machines many +of the experienced aviators are making a business of +the instruction of amateurs. Curtiss and the Wrights +in this country have a number of pupils, as have also +the prominent foreigners. Schools of instruction are +being opened in various parts of the world, not alone as +private money-making ventures, but in connection with +public educational institutions. One of these latter is +to be found at the University of Barcelona, Spain. + +The flying machine agent, the man who handles the +machines on a commission, has also become a known +quantity, and will soon be as numerous as his brother +of the automobile. The sign "John Bird, agent for +Skimmer's Flying Machine," is no longer a curiosity. + +Yes, the Airship Is Here. + +From all of which we may well infer that the flying +machine in practical form has arrived, and that it is +here to stay. It is no exaggeration to say that the time +is close at hand when people will keep flying machines +just as they now keep automobiles, and that pleasure +jaunts will be fully as numerous and popular. With +the important item of practicability fully demonstrated, +"Come, take a trip in my airship," will have more real +significance than now attaches to the vapid warblings +of the vaudeville vocalist. + +As a further evidence that the airship is really here, +and that its presence is recognized in a business way, +the action of life and accident insurance companies is +interesting. Some of them are reconstructing their policies +so as to include a special waiver of insurance by +aviators. Anything which compels these great corporations +to modify their policies cannot be looked upon as +a mere curiosity or toy. + +It is some consolation to know that the movement in +this direction is not thus far widespread. Moreover it +is more than probable that the competition for business +will eventually induce the companies to act more +liberally toward aviators, especially as the art of aviation +advances. + + + +CHAPTER XIX. + +LAW OF THE AIRSHIP. + +Successful aviation has evoked some peculiar things +in the way of legal action and interpretation of the law. + +It is well understood that a man's property cannot +be used without his consent. This is an old established +principle in common law which holds good today. + +The limits of a man's property lines, however, have +not been so well understood by laymen. According to +eminent legal authorities such as Blackstone, Littleton +and Coke, the "fathers of the law," the owner of realty +also holds title above and below the surface, and this +theory is generally accepted without question by the +courts. + +Rights of Property Owners. + +In other words the owner of realty also owns the sky +above it without limit as to distance. He can dig as +deep into his land, or go as high into the air as he desires, +provided he does not trespass upon or injure similar +rights of others. + +The owner of realty may resist by force, all other +means having failed, any trespass upon, or invasion of +his property. Other people, for instance, may not enter +upon it, or over or under it, without his express permission +and consent. There is only one exception, and +this is in the case of public utility corporations such as +railways which, under the law of eminent domain, may +condemn a right of way across the property of an obstinate owner +who declines to accept a fair price for the +privilege. + +Privilege Sharply Confined. + +The law of eminent domain may be taken advantage +of only by corporations which are engaged in serving +the public. It is based upon the principle that the +advancement and improvement of a community is of more +importance and carries with it more rights than the +interests of the individual owner. But even in cases where +the right of eminent domain is exercised there can be no +confiscation of the individual's property. + +Exercising the right of eminent domain is merely +obtaining by public purchase what is held to be essential +to the public good, and which cannot be secured by private +purchase. When eminent domain proceedings are +resorted to the court appoints appraisers who determine +upon the value of the property wanted, and this value +(in money) is paid to the owner. + +How It Affects Aviation. + +It should be kept in mind that this privilege of the +"right of eminent domain" is accorded only to corporations +which are engaged in serving the public. Individuals +cannot take advantage of it. Thus far all aviation +has been conducted by individuals; there are no flying +machine or airship corporations regularly engaged in the +transportation of passengers, mails or freight. + +This leads up to the question "What would happen if +realty owners generally, or in any considerable numbers. +should prohibit the navigation of the air above their +holdings?" It is idle to say such a possibility is ridiculous-- +it is already an actuality in a few individual instances. + +One property owner in New Jersey, a justice of the +peace, maintains a large sign on the roof of his house +warning aviators that they must not trespass upon his +domain. That he is acting well within his rights in doing +this is conceded by legal authorities. + +Hard to Catch Offenders. + +But, suppose the alleged trespass is committed, what +is the property owner going to do about it? He must +first catch the trespasser and this would be a pretty hard +job. He certainly could not overtake him, unless he +kept a racing aeroplane for this special purpose. It +would be equally difficult to indentify the offender after +the offense had been committed, even if he were located, +as aeroplanes carry no license numbers. + +Allowing that the offender should be caught the only +recourse of the realty owner is an action for damages. +He may prevent the commission of the offense by force +if necessary, but after it is committed he can only sue +for damages. And in doing this he would have a lot of +trouble. + +Points to Be Proven. + +One of the first things the plaintiff would be called +upon to prove would be the elevation of the machine. +If it were reasonably close to the ground there would, +of course, be grave risk of damage to fences, shrubbery, +and other property, and the court would be justified in +holding it to be a nuisance that should be suppressed. + +If, on the other hand; the machine was well up in the +air, but going slowly, or hovering over the plaintiff's +property, the court might be inclined to rule that it +could not possibly be a nuisance, but right here the court +would be in serious embarrassment. By deciding that +it was not a nuisance he would virtually override the +law against invasion of a man's property without his +consent regardless of the nature of the invasion. By +the same decision he would also say in effect that, if one +flying machine could do this a dozen or more would +have equal right to do the same thing. While one machine +hovering over a certain piece of property may be +no actual nuisance a dozen or more in the same position +could hardly be excused. + +Difficult to Fix Damages. + +Such a condition would tend to greatly increase the +risk of accident, either through collision, or by the +carelessness +of the aviators in dropping articles which might +cause damages to the people or property below. In +such a case it would undoubtedly be a nuisance, and +in addition to a fine, the offender would also be liable +for the damages. + +Taking it for granted that no actual damage is done, +and the owner merely sues on account of the invasion +of his property, how is the amount of compensation to +be fixed upon? The owner has lost nothing; no part of +his possessions has been taken away; nothing has been +injured or destroyed; everything is left in exactly the +same condition as before the invasion. And yet, if the +law is strictly interpreted, the offender is liable. + +Right of Way for Airships. + +Somebody has suggested the organization of flying- +machine corporations as common carriers, which would +give them the right of eminent domain with power to +condemn a right of way. But what would they condemn? +There is nothing tangible in the air. Railways +in condemning a right of way specify tangible property +(realty) within certain limits. How would an aviator +designate any particular right of way through the air +a certain number of feet in width, and a certain distance +from the ground? + +And yet, should the higher courts hold to the letter +of the law and decide that aviators have no right to +navigate their craft over private property, something +will have to be done to get them out of the dilemma, as +aviation is too far advanced to be discarded. Fortunately +there is little prospect of any widespread antagonism +among property owners so long as aviators refrain +from making nuisances of themselves. + +Possible Solution Offered. + +One possible solution is offered and that is to confine +the path of airships to the public highways so that nobody's +property rights would be invaded. In addition, +as a matter of promoting safety for both operators and +those who may happen to be beneath the airships as +they pass over a course, adoption of the French rules +are suggested. These are as follows: + +Aeroplanes, when passing, must keep to the right, and +pass at a distance of at least 150 feet. They are free +from this rule when flying at altitudes of more than 100 +feet. Every machine when flying at night or during +foggy weather must carry a green light on the right, +and a red light on the left, and a white headlight on the +front. + +These are sensible rules, but may be improved upon +by the addition of a signal system of some kind, either +horn, whistle or bell. + +Responsibility of Aviators. + +Mr. Jay Carver Bossard, in recent numbers of _Fly_, +brings out some curious and interesting legal points in +connection with aviation, among which are the following: + +"Private parties who possess aerial craft, and desire +to operate the same in aerial territory other than their +own, must obtain from land owners special permission +to do so, such permission to be granted only by agreement, +founded upon a valid consideration. Otherwise, +passing over another's land will in each instance amount +to a trespass. + +"Leaving this highly technical side of the question, +let us turn to another view: the criminal and tort liability +of owners and operators to airship passengers. If +A invites B to make an ascension with him in his machine, +and B, knowing that A is merely an enthusiastic +amateur and far from being an expert, accepts and is +through A's innocent negligence injured, he has no +grounds for recovery. But if A contracts with B, to +transport him from one place to another, for a consideration, +and B is injured by the poor piloting of A, +A would be liable to B for damages which would result. +Now in order to safeguard such people as B, curious to +the point of recklessness, the law will have to require +all airship operators to have a license, and to secure +this license airship pilots will have to meet certain +requirements. Here again is a question. Who is going +to say whether an applicant is competent to pilot a balloon +or airship? + +Fine for an Aeronaut. + +"An aeroplane while maneuvering is suddenly caught +by a treacherous gale and swept to the ground. A crowd +of people hasten over to see if the aeronaut is injured, +and in doing so trample over Tax-payer Smith's garden, +much to the detriment of his growing vegetables and +flowers. Who is liable for the damages? Queer as it +may seem, a case very similar to this was decided in +1823, in the New York supreme court, and it was held +that the aeronaut was liable upon the following grounds: +'To render one man liable in trespass for the acts of +others, it must appear either that they acted in concert, +or that the act of the one, ordinarily and naturally produced +the acts of the others, Ascending in a balloon is +not an unlawful act, but it is certain that the aeronaut +has no control over its motion horizontally, but is at +the sport of the wind, and is to descend when and how +he can. His reaching the earth is a matter of hazard. +If his descent would according to the circumstances +draw a crowd of people around him, either out of curiosity, +or for the purpose of rescuing him from a perilous +situation, all this he ought to have foreseen, and must be +responsible for.' + +Air Not Really Free. + +"The general belief among people is, that the air is +free. Not only free to breathe and enjoy, but free to +travel in, and that no one has any definite jurisdiction +over, or in any part of it. Now suppose this were made a +legal doctrine. Would a murder perpetrated above the +clouds have to go unpunished? Undoubtedly. For felonies +committed upon the high seas ample provision is +made for their punishment, but new provisions will have +to be made for crimes committed in the air. + +Relations of Owner and Employee. + +"It is a general rule of law that a master is bound to +provide reasonably safe tools, appliances and machines +for his servant. How this rule is going to be applied +in cases of aeroplanes, remains to be seen. The aeroplane +owner who hires a professional aeronaut, that is, +one who has qualified as an expert, owes him very little +legal duty to supply him with a perfect aeroplane. The +expert is supposed to know as much regarding the machine +as the owner, if not more, and his acceptance of +his position relieves the owner from liability. When +the owner hires an amateur aeronaut to run the aeroplane, and +teaches him how to manipulate it, even though +the prescribed manner of manipulation will make flight +safe, nevertheless if the machine is visibly defective, or +known to be so, any injury which results to the aeronaut +the owner is liable for. + +As to Aeroplane Contracts. + +"At the present time there are many orders being +placed with aeroplane manufacturing companies. There +are some unique questions to be raised here under the +law of contract. It is an elementary principle of law +that no one can be compelled to complete a contract +which in itself is impossible to perform. For instance, +a contract to row a boat across the Atlantic in two +weeks, for a consideration, could never be enforced because +it is within judicial knowledge that such an undertaking +is beyond human power. Again, contracts formed +for the doing of acts contrary to nature are never +enforcible, and here is where our difficulty comes in. Is +it possible to build a machine or species of craft which +will transport a person or goods through the air? The +courts know that balloons are practical; that is, they +know that a bag filled with gas has a lifting power and +can move through the air at an appreciable height. +Therefore, a contract to transport a person in such manner +is a good contract, and the conditions being favorable +could undoubtedly be enforced. But the passengers' +right of action for injury would be very limited. + +No Redress for Purchasers. + +"In the case of giving warranties on aeroplanes, we +have yet to see just what a court is going to say. It is +easy enough for a manufacturer to guarantee to build a +machine of certain dimensions and according to certain +specifications, but when he inserts a clause in the contract to +the effect that the machine will raise itself from +the surface of the earth, defy the laws of gravity, and +soar in the heavens at the will of the aviator, he is to +say the least contracting to perform a miracle. + +"Until aeroplanes have been made and accepted as +practical, no court will force a manufacturer to turn out +a machine guaranteed to fly. So purchasers can well +remember that if their machines refuse to fly they have +no redress against the maker, for he can always say, +'The industry is still in its experimental stage.' In +contracting for an engine no builder will guarantee that +the particular engine will successfully operate the aeroplane. +In fact he could never be forced to live up to +such an agreement, should he agree to a stipulation of +that sort. The best any engine maker will guarantee +is to build an engine according to specifications." + + + +CHAPTER XX. + +SOARING FLIGHT. + +By Octave Chanute. + +[5]There is a wonderful performance daily exhibited in +southern climes and occasionally seen in northerly +latitudes in summer, which has never been thoroughly +explained. It is the soaring or sailing flight of certain +varieties of large birds who transport themselves on rigid, +unflapping wings in any desired direction; who in winds +of 6 to 20 miles per hour, circle, rise, advance, return and +remain aloft for hours without a beat of wing, save for +getting under way or convenience in various maneuvers. +They appear to obtain from the wind alone all the necessary +energy, even to advancing dead against that wind. +This feat is so much opposed to our general ideas of +physics that those who have not seen it sometimes deny +its actuality, and those who have only occasionally +witnessed it subsequently doubt the evidence of their own +eyes. Others, who have seen the exceptional performances, +speculate on various explanations, but the majority +give it up as a sort of "negative gravity." + +[5] Aeronautics. + +Soaring Power of Birds. + +The writer of this paper published in the "Aeronautical +Annual" for 1896 and 1897 an article upon the sailing +flight of birds, in which he gave a list of the authors who +had described such flight or had advanced theories for +its explanation, and he passed these in review. He also +described his own observations and submitted some computations +to account for the observed facts. These computations +were correct as far as they went, but they were +scanty. It was, for instance, shown convincingly by +analysis that a gull weighing 2.188 pounds, with a total +supporting surface of 2.015 square feet, a maximum body +cross-section of 0.126 square feet and a maximum cross- +section of wing edges of 0.098 square feet, patrolling on +rigid wings (soaring) on the weather side of a steamer +and maintaining an upward angle or attitude of 5 degrees +to 7 degrees above the horizon, in a wind blowing 12.78 +miles an hour, which was deflected upward 10 degrees +to 20 degrees by the side of the steamer (these all being +carefully observed facts), was perfectly sustained at its +own "relative speed" of 17.88 miles per hour and extracted +from the upward trend of the wind sufficient energy +to overcome all the resistances, this energy +amounting to 6.44 foot-pounds per second. + +Great Power of Gulls. + +It was shown that the same bird in flapping flight in +calm air, with an attitude or incidence of 3 degrees to 5 +degrees above the horizon and a speed of 20.4 miles an +hour was well sustained and expended 5.88 foot-pounds +per second, this being at the rate of 204 pounds sustained +per horsepower. It was stated also that a gull in its observed +maneuvers, rising up from a pile head on unflapping +wings, then plunging forward against the wind and +subsequently rising higher than his starting point, must +either time his ascents and descents exactly with the +variations in wind velocities, or must meet a wind billow +rotating on a horizontal axis and come to a poise on its +crest, thus availing of an ascending trend. + +But the observations failed to demonstrate that the +variations of the wind gusts and the movements of the +bird were absolutely synchronous, and it was conjectured +that the peculiar shape of the soaring wing of certain +birds, as differentiated from the flapping wing, might, +when experimented upon, hereafter account for the performance. + +Mystery to be Explained. + +These computations, however satisfactory they were +for the speed of winds observed, failed to account for the +observed spiral soaring of buzzards in very light winds +and the writer was compelled to confess: "Now, this +spiral soaring in steady breezes of 5 to 10 miles per hour +which are apparently horizontal, and through which the +bird maintains an average speed of about 20 miles an +hour, is the mystery to be explained. It is not accounted +for, quantitatively, by any of the theories which have +been advanced, and it is the one performance which has +led some observers to claim that it was done through +'aspiration.' i, e., that a bird acted upon by a current, +actually drew forward into that current against its exact +direction of motion." + +Buzzards Soar in Dead Calm. + +A still greater mystery was propounded by the few +observers who asserted that they had seen buzzards soaring +in a dead calm, maintaining their elevation and their +speed. Among these observers was Mr. E. C. Huffaker, +at one time assistant experimenter for Professor Langley. +The writer believed and said then that he must in some +way have been mistaken, yet, to satisfy himself, he paid +several visits to Mr. Huffaker, in Eastern Tennessee and +took along his anemometer. He saw quite a number of +buzzards sailing at a height of 75 to 100 feet in breezes +measuring 5 or 6 miles an hour at the surface of the +ground, and once he saw one buzzard soaring apparently +in a dead calm. + +The writer was fairly baffled. The bird was not simply +gliding, utilizing gravity or acquired momentum, he was +actually circling horizontally in defiance of physics and +mathematics. It took two years and a whole series of +further observations to bring those two sciences into +accord with the facts. + +Results of Close Observations. + +Curiously enough the key to the performance of circling +in a light wind or a dead calm was not found +through the usual way of gathering human knowledge, +i. e., through observations and experiment. These had +failed because I did not know what to look for. The +mystery was, in fact, solved by an eclectic process of +conjecture and computation, but once these computations +indicated what observations should be made, the results +gave at once the reasons for the circling of the birds, for +their then observed attitude, and for the necessity of an +independent initial sustaining speed before soaring began. +Both Mr. Huffaker and myself verified the data +many times and I made the computations. + +These observations disclosed several facts: + +1st.--That winds blowing five to seventeen miles per +hour frequently had rising trends of 10 degrees to 15 +degrees, and that upon occasions when there seemed to be +absolutely no wind, there was often nevertheless a local +rising of the air estimated at a rate of four to eight miles +or more per hour. This was ascertained by watching +thistledown, and rising fogs alongside of trees or hills of +known height. Everyone will readily realize that when +walking at the rate of four to eight miles an hour in a +dead calm the "relative wind" is quite inappreciable to +the senses and that such a rising air would not be noticed. + +2nd.--That the buzzard, sailing in an apparently dead +horizontal calm, progressed at speeds of fifteen to eighteen +miles per hour, as measured by his shadow on the +ground. It was thought that the air was then possibly +rising 8.8 feet per second, or six miles per hour. + +3rd.--That when soaring in very light winds the angle +of incidence of the buzzards was negative to the horizon +--i. e., that when seen coming toward the eye, the afternoon +light shone on the back instead of on the breast, +as would have been the case had the angle been inclined +above the horizon. + +4th.--That the sailing performance only occurred after +the bird had acquired an initial velocity of at least fifteen +or eighteen miles per hour, either by industrious flapping +or by descending from a perch. + +An Interesting Experiment. + +5th.--That the whole resistance of a stuffed buzzard, +at a negative angle of 3 degrees in a current of air of +15.52 miles per hour, was 0.27 pounds. This test was +kindly made for the writer by Professor A. F. Zahm in +the "wind tunnel" of the Catholic University at Washington, +D. C., who, moreover, stated that the resistance +of a live bird might be less, as the dried plumage could +not be made to lie smooth. + +This particular buzzard weighed in life 4.25 pounds, +the area of his wings and body was 4.57 square feet, the +maximum cross-section of his body was 0.110 square feet, +and that of his wing edges when fully extended was +0.244 square feet. + +With these data, it became surprisingly easy to compute +the performance with the coefficients of Lilienthal +for various angles of incidence and to demonstrate how +this buzzard could soar horizontally in a dead horizontal +calm, provided that it was not a vertical calm, and that +the air was rising at the rate of four or six miles per +hour, the lowest observed, and quite inappreciable without +actual measuring. + +Some Data on Bird Power. + +The most difficult case is purposely selected. For if +we assume that the bird has previously acquired an initial +minimum speed of seventeen miles an hour (24.93 +feet per second, nearly the lowest measured), and that +the air was rising vertically six miles an hour (8.80 feet +per second), then we have as the trend of the "relative +wind" encountered: + + 6 + -- = 0.353, or the tangent of 19 degrees 26'. + 17 + +which brings the case into the category of rising wind +effects. But the bird was observed to have a negative +angle to the horizon of about 3 degrees, as near as could be +guessed, so that his angle of incidence to the "relative +wind" was reduced to 16 degrees 26'. + +The relative speed of his soaring was therefore: + +Velocity = square root of (17 squared + 6 squared) = 18.03 miles +per hour. + +At this speed, using the Langley co-efficient recently +practically confirmed by the accurate experiments of Mr. +Eiffel, the air pressure would be: + +18.03 squared X 0.00327 = 1.063 pounds per square foot. + +If we apply Lilienthal's co-efficients for an angle of +6 degrees 26', we have for the force in action: + +Normal: 4.57 X 1.063 X 0.912 = 4.42 pounds. + +Tangential: 4.57 X 1.063 X 0.074 = - 0.359 pounds, +which latter, being negative, is a propelling force. + +Results Astonish Scientists. + +Thus we have a bird weighing 4.25 pounds not only +thoroughly supported, but impelled forward by a force +of 0.359 pounds, at seventeen miles per hour, while the +experiments of Professor A. F. Zahm showed that the +resistance at 15.52 miles per hour was only 0.27 pounds, + 17 squared +or 0.27 X ------- = 0.324 pounds, at seventeen miles an + 15.52 squared +hour. + +These are astonishing results from the data obtained, +and they lead to the inquiry whether the energy of the +rising air is sufficient to make up the losses which occur +by reason of the resistance and friction of the bird's body +and wings, which, being rounded, do not encounter air +pressures in proportion to their maximum cross-section. + +We have no accurate data upon the co-efficients to apply +and estimates made by myself proved to be much +smaller than the 0.27 pounds resistance measured by +Professor Zahm, so that we will figure with the latter +as modified. As the speed is seventeen miles per hour, or +24.93 feet per second, we have for the work: + +Work done, 0.324 X 24.93 = 8.07 foot pounds per second. + +Endorsed by Prof. Marvin. + +Corresponding energy of rising air is not sufficient at +four miles per hour. This amounts to but 2.10 foot pounds +per second, but if we assume that the air was rising at +the rate of seven miles per hour (10.26 feet per second), +at which the pressure with the Langley coefficient would +be 0.16 pounds per square foot, we have on 4.57 square +feet for energy of rising air: 4.57 X 0.16 X 10.26 = 7.50 +foot pounds per second, which is seen to be still a little +too small, but well within the limits of error, in view of +the hollow shape of the bird's wings, which receive +greater pressure than the flat planes experimented upon +by Langley. + +These computations were chiefly made in January, +1899, and were communicated to a few friends, who found +no fallacy in them, but thought that few aviators would +understand them if published. They were then submitted +to Professor C. F. Marvin of the Weather Bureau, who +is well known as a skillful physicist and mathematician. +He wrote that they were, theoretically, entirely sound +and quantitatively, probably, as accurate as the present +state of the measurements of wind pressures permitted. +The writer determined, however, to withhold publication +until the feat of soaring flight had been performed by +man, partly because he believed that, to ensure safety, it +would be necessary that the machine should be equipped +with a motor in order to supplement any deficiency in +wind force. + +Conditions Unfavorable for Wrights. + +The feat would have been attempted in 1902 by Wright +brothers if the local circumstances had been more favorable. +They were experimenting on "Kill Devil Hill," +near Kitty Hawk, N. C. This sand hill, about 100 feet +high, is bordered by a smooth beach on the side whence +come the sea breezes, but has marshy ground at the back. +Wright brothers were apprehensive that if they rose on +the ascending current of air at the front and began to +circle like the birds, they might be carried by the +descending current past the back of the hill and land in +the marsh. Their gliding machine offered no greater +head resistance in proportion than the buzzard, and their gliding +angles of descent are practically as favorable, but +the birds performed higher up in the air than they. + +Langley's Idea of Aviation. + +Professor Langley said in concluding his paper upon +"The Internal Work of the Wind": + +"The final application of these principles to the art of +aerodromics seems, then, to be, that while it is not likely +that the perfected aerodrome will ever be able to dispense +altogether with the ability to rely at intervals on +some internal source of power, it will not be indispensable +that this aerodrome of the future shall, in order to +go any distance--even to circumnavigate the globe without +alighting--need to carry a weight of fuel which +would enable it to perform this journey under conditions +analogous to those of a steamship, but that the fuel and +weight need only be such as to enable it to take care of +itself in exceptional moments of calm." + +Now that dynamic flying machines have been evolved +and are being brought under control, it seems to be +worth while to make these computations and the succeeding +explanations known, so that some bold man will +attempt the feat of soaring like a bird. The theory +underlying the performance in a rising wind is not new, +it has been suggested by Penaud and others, but it has +attracted little attention because the exact data and the +maneuvers required were not known and the feat had +not yet been performed by a man. The puzzle has always +been to account for the observed act in very light +winds, and it is hoped that by the present selection of +the most difficult case to explain--i. e., the soaring in a +dead horizontal calm--somebody will attempt the exploit. + +Requisites for Soaring Flights. + +The following are deemed to be the requisites and +maneuvers to master the secrets of soaring flight: + +1st--Develop a dynamic flying machine weighing +about one pound per square foot of area, with stable +equilibrium and under perfect control, capable of gliding +by gravity at angles of one in ten (5 3/4 degrees) in still air. + +2nd.--Select locations where soaring birds abound and +occasions where rising trends of gentle winds are frequent +and to be relied on. + +3rd.--Obtain an initial velocity of at least 25 feet per +second before attempting to soar. + +4th.--So locate the center of gravity that the apparatus +shall assume a negative angle, fore and aft, of about 3 degrees. + +Calculations show, however, that sufficient propelling +force may still exist at 0 degrees, but disappears entirely at ++4 degrees. + +5th.--Circle like the bird. Simultaneously with the +steering, incline the apparatus to the side toward which +it is desired to turn, so that the centrifugal force shall +be balanced by the centripetal force. The amount of the +required inclination depends upon the speed and on the +radius of the circle swept over. + +6th.--Rise spirally like the bird. Steer with the +horizontal rudder, so as to descend slightly when going +with the wind and to ascend when going against the +wind. The bird circles over one spot because the rising +trends of wind are generally confined to small areas or +local chimneys, as pointed out by Sir H. Maxim and +others. + +7th.--Once altitude is gained, progress may be made +in any direction by gliding downward by gravity. + +The bird's flying apparatus and skill are as yet infinitely +superior to those of man, but there are indications that +within a few years the latter may evolve more accurately +proportioned apparatus and obtain absolute control over +it. + +It is hoped, therefore, that if there be found no radical +error in the above computations, they will carry the conviction +that soaring flight is not inaccessible to man, as +it promises great economies of motive power in favorable +localities of rising winds. + +The writer will be grateful to experts who may point +out any mistake committed in data or calculations, and +will furnish additional information to any aviator who +may wish to attempt the feat of soaring. + + + +CHAPTER XXI. + +FLYING MACHINES VS. BALLOONS. + +While wonderful success has attended the development +of the dirigible (steerable) balloon the most ardent +advocates of this form of aerial navigation admit that it +has serious drawbacks. Some of these may be described +as follows: + +Expense and Other Items. + +Great Initial Expense.--The modern dirigible balloon +costs a fortune. The Zeppelin, for instance, costs more +than $100,000 (these are official figures). + +Expense of Inflation.--Gas evaporates rapidly, and a +balloon must be re-inflated, or partially re-inflated, every +time it is used. The Zeppelin holds 460,000 cubic feet +of gas which, even at $1 per thousand, would cost $460. + +Difficulty of Obtaining Gas.--If a balloon suddenly +becomes deflated, by accident or atmospheric conditions, +far from a source of gas supply, it is practically worthless. +Gas must be piped to it, or the balloon carted to +the gas house--an expensive proceeding in either event. + +Lack of Speed and Control. + +Lack of Speed.--Under the most favorable conditions +the maximum speed of a balloon is 30 miles an hour. +Its great bulk makes the high speed attained by flying +machines impossible. + +Difficulty of Control.--While the modern dirigible balloon is +readily handled in calm or light winds, its bulk +makes it difficult to control in heavy winds. + +The Element of Danger.--Numerous balloons have +been destroyed by lightning and similar causes. One of +the largest of the Zeppelins was thus lost at Stuttgart +in 1908. + +Some Balloon Performances. + +It is only a matter of fairness to state that, under +favorable conditions, some very creditable records have +been made with modern balloons, viz: + +November 23d, 1907, the French dirigible Patrie, travelled +187 miles in 6 hours and 45 minutes against a +light wind. This was a little over 28 miles an hour. + +The Clement-Bayard, another French machine, sold +to the Russian government, made a trip of 125 miles at +a rate of 27 miles an hour. + +Zeppelin No. 3, carrying eight passengers, and having +a total lifting capacity of 5,500 pounds of ballast in +addition to passengers, weight of equipment, etc., was +tested in October, 1906, and made 67 miles in 2 hours +and 17 minutes, about 30 miles an hour. + +These are the best balloon trips on record, and show +forcefully the limitations of speed, the greatest being not +over 30 miles an hour. + +Speed of Flying Machines. + +Opposed to the balloon performances we have flying +machine trips (of authentic records) as follows: + +Bleriot--monoplane--in 1908--52 miles an hour. + +Delagrange--June 22, 1908--10 1/2 miles in 16 minutes, +approximately 42 miles an hour. + +Wrights--October, 1905--the machine was then in its +infancy--24 miles in 38 minutes, approximately 44 miles +an hour. On December 31, 1908, the Wrights made 77 +miles in 2 hours and 20 minutes. + +Lambert, a pupil of the Wrights, and using a Wright +biplane, on October 18, 1909, covered 29.82 miles in 49 +minutes and 39 seconds, being at the rate of 36 miles +an hour. This flight was made at a height of 1,312 feet. + +Latham--October 21, 1909--made a short flight, about +11 minutes, in the teeth of a 40 mile gale, at Blackpool, +Eng. He used an Antoniette monoplane, and the official +report says: "This exhibition of nerve, daring and ability +is unparalled in the history of aviation." + +Farman--October 20, 1909--was in the air for 1 hour, +32 min., 16 seconds, travelling 47 miles, 1,184 yards, a +duration record for England. + +Paulhan--January 18, 1901--47 1/2 miles at the rate of +45 miles an hour, maintaining an altitude of from 1,000 +to 2,000 feet. + +Expense of Producing Gas. + +Gas is indispensable in the operation of dirigible balloons, +and gas is expensive. Besides this it is not always +possible to obtain it in sufficient quantities even in large +cities, as the supply on hand is generally needed for +regular customers. Such as can be had is either water +or coal gas, neither of which is as efficient in lifting +power as hydrogen. + +Hydrogen is the lightest and consequently the most +buoyant of all known gases. It is secured commercially +by treating zinc or iron with dilute sulphuric or +hydrochloric acid. The average cost may be safely placed +at $10 per 1,000 feet so that, to inflate a balloon of the +size of the Zeppelin, holding 460,000 cubic feet, would +cost $4,600. + +Proportions of Materials Required. + +In making hydrogen gas it is customary to allow 20 +per cent for loss between the generation and the introduction +of the gas into the balloon. Thus, while the +formula calls for iron 28 times heavier than the weight +of the hydrogen required, and acid 49 times heavier, the +real quantities are 20 per cent greater. Hydrogen weighs +about 0.09 ounce to the cubic foot. Consequently if we +need say 450,000 cubic feet of gas we must have 2,531.25 +pounds in weight. To produce this, allowing for the 20 +percent loss, we must have 35 times its weight in iron, +or over 44 tons. Of acid it would take 60 times the +weight of the gas, or nearly 76 tons. + +In Time of Emergency. + +These figures are appalling, and under ordinary conditions +would be prohibitive, but there are times when +the balloon operator, unable to obtain water or coal gas, +must foot the bills. In military maneuvers, where the +field of operation is fixed, it is possible to furnish supplies +of hydrogen gas in portable cylinders, but on long +trips where sudden leakage or other cause makes descent +in an unexpected spot unavoidable, it becomes a question +of making your own hydrogen gas or deserting the balloon. +And when this occurs the balloonist is up against +another serious proposition--can he find the necessary +zinc or iron? Can he get the acid? + +Balloons for Commercial Use. + +Despite all this the balloon has its uses. If there is to +be such a thing as aerial navigation in a commercial +way--the carrying of freight and passengers--it will +come through the employment of such monster balloons +as Count Zeppelin is building. But even then the carrying +capacity must of necessity be limited. The latest +Zeppelin creation, a monster in size, is 450 feet long, +and 42 1/2 feet in diameter. The dimensions are such as +to make all other balloons look like pigmies; even many +ocean-going steamers are much smaller, and yet its passenger +capacity is very small. On its 36-hour flight in +May, 1909, the Zeppelin, carried only eight passengers. +The speed, however, was quite respectable, 850 miles +being covered in the 36 hours, a trifle over 23 miles an +hour. The reserve buoyancy, that is the total lifting +capacity aside from the weight of the airship and its +equipment, is estimated at three tons. + + + +CHAPTER XXII. + +PROBLEMS OF AERIAL FLIGHT. + +In a lecture before the Royal Society of Arts, reported +in Engineering, F. W. Lanchester took the position that +practical flight was not the abstract question which some +apparently considered it to be, but a problem in locomotive +engineering. The flying machine was a locomotive +appliance, designed not merely to lift a weight, +but to transport it elsewhere, a fact which should be +sufficiently obvious. Nevertheless one of the leading scientific +men of the day advocated a type in which this, the +main function of the flying machine, was overlooked. +When the machine was considered as a method of transport, +the vertical screw type, or helicopter, became at +once ridiculous. It had, nevertheless, many advocates +who had some vague and ill-defined notion of subsequent +motion through the air after the weight was raised. + +Helicopter Type Useless. + +When efficiency of transport was demanded, the helicopter +type was entirely out of court. Almost all of +its advocates neglected the effect of the motion of the +machine through the air on the efficiency of the vertical +screws. They either assumed that the motion was +so slow as not to matter, or that a patch of still air +accompanied the machine in its flight. Only one form of this +type had any possibility of success. In this there were +two screws running on inclined axles--one on each side +of the weight to be lifted. The action of such inclined +screw was curious, and in a previous lecture he had +pointed out that it was almost exactly the same as that +of a bird's wing. In high-speed racing craft such inclined +screws were of necessity often used, but it was +at a sacrifice of their efficiency. In any case the efficiency +of the inclined-screw helicopter could not compare +with that of an aeroplane, and that type might be +dismissed from consideration so soon as efficiency became +the ruling factor of the design. + +Must Compete With Locomotive. + +To justify itself the aeroplane must compete, in some +regard or other, with other locomotive appliances, performing +one or more of the purposes of locomotion more +efficiently than existing systems. It would be no use +unless able to stem air currents, so that its velocity must +he greater than that of the worst winds liable to be encountered. +To illustrate the limitations imposed on the +motion of an aeroplane by wind velocity, Mr. Lanchester +gave the diagrams shown in Figs. 1 to 4. The circle +in each case was, he said, described with a radius equal +to the speed of the aeroplane in still air, from a center +placed "down-wind" from the aeroplane by an amount +equal to the velocity of the wind. + +Fig. 1 therefore represented the case in which the +air was still, and in this case the aeroplane represented +by _A_ had perfect liberty of movement in any direction + +In Fig. 2 the velocity of the wind was half that of the +aeroplane, and the latter could still navigate in any +direction, but its speed against the wind was only one- +third of its speed with the wind. + +In Fig. 3 the velocity of the wind was equal to that +of the aeroplane, and then motion against the wind was +impossible; but it could move to any point of the +circle, but not to any point lying to the left of the tangent +_A_ _B_. Finally, when the wind had a greater +speed than the aeroplane, as in Fig. 4, the machine could +move only in directions limited by the tangents _A_ _C_ +and _A_ _D_. + +Matter of Fuel Consumption. + +Taking the case in which the wind had a speed equal +to half that of the aeroplane, Mr. Lanchester said that +for a given journey out and home, down wind and back, +the aeroplane would require 30 per cent more fuel than +if the trip were made in still air; while if the journey +was made at right angles to the direction of the wind +the fuel needed would be 15 per cent more than in a +calm. This 30 per cent extra was quite a heavy enough +addition to the fuel; and to secure even this figure it +was necessary that the aeroplane should have a speed of +twice that of the maximum wind in which it was desired +to operate the machine. Again, as stated in the last +lecture, to insure the automatic stability of the machine +it was necessary that the aeroplane speed should be +largely in excess of that of the gusts of wind liable to +be encountered. + +Eccentricities of the Wind. + +There was, Mr. Lanchester said, a loose connection +between the average velocity of the wind and the maximum +speed of the gusts. When the average speed of +the wind was 40 miles per hour, that of the gusts might +be equal or more. At one moment there might be a +calm or the direction of the wind even reversed, followed, +the next moment, by a violent gust. About the same +minimum speed was desirable for security against gusts +as was demanded by other considerations. Sixty miles +an hour was the least figure desirable in an aeroplane, +and this should be exceeded as much as possible. Actually, +the Wright machine had a speed of 38 miles per +hour, while Farman's Voisin machine flew at 45 miles +per hour. + +Both machines were extremely sensitive to high winds, +and the speaker, in spite of newspaper reports to the +contrary, had never seen either flown in more than a +gentle breeze. The damping out of the oscillations of +the flight path, discussed in the last lecture, increased +with the fourth power of the natural velocity of flight, +and rapid damping formed the easiest, and sometimes +the only, defense against dangerous oscillations. A +machine just stable at 35 miles per hour would have +reasonably rapid damping if its speed were increased to +60 miles per hour. + +Thinks Use Is Limited. + +It was, the lecturer proceeded, inconceivable that any +very extended use should be made of the aeroplane unless +the speed was much greater than that of the motor car. +It might in special cases be of service, apart from this +increase of speed, as in the exploration of countries +destitute of roads, but it would have no general utility. +With an automobile averaging 25 to 35 miles per hour, +almost any part of Europe, Russia excepted, was attainable +in a day's journey. A flying machine of but +equal speed would have no advantages, but if the speed +could be raised to 90 or 100 miles per hour, the whole +continent of Europe would become a playground, every +part being within a daylight flight of Berlin. Further, +some marine craft now had speeds of 40 miles per hour, +and efficiently to follow up and report movements of +such vessels an aeroplane should travel at 60 miles per +hour at least. Hence from all points of view appeared +the imperative desirability of very high velocities of +flight. The difficulties of achievement were, however, +great. + +Weight of Lightest Motors. + +As shown in the first lecture of his course, the resistance +to motion was nearly independent of the velocity, +so that the total work done in transporting a given +weight was nearly constant. Hence the question of fuel +economy was not a bar to high velocities of flight, though +should these become excessive, the body resistance might +constitute a large proportion of the total. The horsepower +required varied as the velocity, so the factor governing +the maximum velocity of flight was the horsepower +that could be developed on a given weight. At +present the weight per horsepower of feather-weight +motors appeared to range from 2 1/4 pounds up to 7 +pounds per brake horsepower, some actual figures being +as follows: + +Antoinette........ 5 lbs. +Fiat.............. 3 lbs. +Gnome....... Under 3 lbs. +Metallurgic....... 8 lbs. +Renault........... 7 lbs. +Wright.............6 lbs. + +Automobile engines, on the other hand, commonly +weighed 12 pounds to 13 pounds per brake horsepower. + +For short flights fuel economy was of less importance +than a saving in the weight of the engine. For long +flights, however, the case was different. Thus, if the +gasolene consumption was 1/2 pound per horsepower hour, +and the engine weighed 3 pounds per brake horsepower, +the fuel needed for a six-hour flight would weigh as much +as the engine, but for half an hour's flight its weight +would be unimportant. + +Best Means of Propulsion. + +The best method of propulsion was by the screw, +which acting in air was subject to much the same conditions +as obtained in marine work. Its efficiency depended +on its diameter and pitch and on its position, +whether in front of or behind the body propelled. From +this theory of dynamic support, Mr. Lanchester proceeded, +the efficiency of each element of a screw propeller +could be represented by curves such as were given +in his first lecture before the society, and from these +curves the over-all efficiency of any proposed propeller +could be computed, by mere inspection, with a fair degree +of accuracy. These curves showed that the tips of +long-bladed propellers were inefficient, as was also the +portion of the blade near the root. In actual marine +practice the blade from boss to tip was commonly of +such a length that the over-all efficiency was 95 per cent +of that of the most efficient element of it. + +Advocates Propellers in Rear. + +From these curves the diameter and appropriate pitch +of a screw could be calculated, and the number of +revolutions was then fixed. Thus, for a speed of 80 feet +per second the pitch might come out as 8 feet, in which +case the revolutions would be 600 per minute, which +might, however, be too low for the motor. It was then +necessary either to gear down the propeller, as was done +in the Wright machine, or, if it was decided to drive it +direct, to sacrifice some of the efficiency of the propeller. +An analogous case arose in the application of the steam +turbine to the propulsion of cargo boats, a problem as +yet unsolved. The propeller should always be aft, so +that it could abstract energy from the wake current, and +also so that its wash was clear of the body propelled. +The best possible efficiency was about 70 per cent, and +it was safe to rely upon 66 per cent. + +Benefits of Soaring Flight. + +There was, Mr. Lanchester proceeded, some possibility +of the aeronaut reducing the power needed for transport +by his adopting the principle of soaring flight, as +exemplified by some birds. There were, he continued, two +different modes of soaring flight. In the one the bird +made use of the upward current of air often to be found +in the neighborhood of steep vertical cliffs. These cliffs +deflected the air upward long before it actually reached +the cliff, a whole region below being thus the seat of +an upward current. Darwin has noted that the condor +was only to be found in the neighborhood of such cliffs. +Along the south coast also the gulls made frequent use +of the up currents due to the nearly perpendicular chalk +cliffs along the shore. + +In the tropics up currents were also caused by +temperature differences. Cumulus clouds, moreover, were +nearly always the terminations of such up currents of +heated air, which, on cooling by expansion in the upper +regions, deposited their moisture as fog. These clouds +might, perhaps, prove useful in the future in showing +the aeronaut where up currents were to he found. An- +other mode of soaring flight was that adopted by the +albatross, which took advantage of the fact that the air +moved in pulsations, into which the bird fitted itself, +being thus able to extract energy from the wind. +Whether it would be possible for the aeronaut to employ +a similar method must be left to the future to decide. + +Main Difficulties in Aviation. + +In practical flight difficulties arose in starting and in +alighting. There was a lower limit to the speed at +which the machine was stable, and it was inadvisable to +leave the ground till this limit was attained. Similarly, +in alighting it was inexpedient to reduce the speed below +the limit of stability. This fact constituted a difficulty +in the adoption of high speeds, since the length of run +needed increased in proportion to the square of the +velocity. This drawback could, however, be surmounted +by forming starting and alighting grounds of ample size. +He thought it quite likely in the future that such grounds +would be considered as essential to the flying machine +as a seaport was to an ocean-going steamer or as a road +was to the automobile. + +Requisites of Flying Machine. + +Flying machines were commonly divided into monoplanes +and biplanes, according as they had one or two +supporting surfaces. The distinction was not, however, +fundamental. To get the requisite strength some form +of girder framework was necessary, and it was a mere +question of convenience whether the supporting surface +was arranged along both the top and the bottom of this +girder, or along the bottom only. The framework adopted +universally was of wood braced by ties of pianoforte +wire, an arrangement giving the stiffness desired with +the least possible weight. Some kind of chassis was also +necessary. + + + +CHAPTER XXIII. + +AMATEURS MAY USE WRIGHT PATENTS. + +Owing to the fact that the Wright brothers have enjoined +a number of professional aviators from using +their system of control, amateurs have been slow to +adopt it. They recognize its merits, and would like to +use the system, but have been apprehensive that it +might involve them in litigation. There is no danger +of this, as will be seen by the following statement made +by the Wrights: + +What Wright Brothers Say. + +"Any amateur, any professional who is not exhibiting +for money, is at liberty to use our patented devices. +We shall be glad to have them do so, and there will be +no interference on our part, by legal action, or otherwise. +The only men we proceed against are those who, without +our permission, without even asking our consent, +coolly appropriate the results of our labors and use them +for the purpose of making money. Curtiss, Delagrange, +Voisin, and all the rest of them who have used our +devices have done so in money-making exhibitions. So +long as there is any money to be made by the use of the +products of our brains, we propose to have it ourselves. +It is the only way in which we can get any return for +the years of patient work we have given to the problem +of aviation. On the other hand, any man who wants +to use these devices for the purpose of pleasure, or the +advancement of science, is welcome to do so, without +money and without price. This is fair enough, is it not?" + +Basis of the Wright Patents. + +In a flying machine a normally flat aeroplane having +lateral marginal portions capable of movement to different +positions above or below the normal plane of the +body of the aeroplane, such movement being about an +axis transverse to the line of flight, whereby said lateral +marginal portions may be moved to different angles relatively +to the normal plane of the body of the aeroplane, +so as to present to the atmosphere different angles +of incidence, and means for so moving said lateral marginal +portions, substantially as described. + +Application of vertical struts near the ends having +flexible joints. + +Means for simultaneously imparting such movement +to said lateral portions to different angles relatively to +each other. + +Refers to the movement of the lateral portions on the +same side to the same angle. + +Means for simultaneously moving vertical rudder so +as to present to the wind that side thereof nearest the +side of the aeroplane having the smallest angle of incidence. + +Lateral stability is obtained by warping the end wings +by moving the lever at the right hand of the operator, +connection being made by wires from the lever to the +wing tips. The rudder may also be curved or warped in +similar manner by lever action. + +Wrights Obtain an Injunction. + +In January, 1910, Judge Hazel, of the United States +Circuit Court, granted a preliminary injunction restraining +the Herring-Curtiss Co., and Glenn H. Curtiss, from +manufacturing, selling, or using for exhibition purposes +the machine known as the Curtiss aeroplane. The injunction +was obtained on the ground that the Curtiss +machine is an infringement upon the Wright patents in +the matter of wing warping and rudder control. + +It is not the purpose of the authors to discuss the +subject pro or con. Such discussion would have no proper +place in a volume of this kind. It is enough to say that +Curtiss stoutly insists that his machine is not an +infringement of the Wright patents, although Judge Hazel +evidently thinks differently. + +What the Judge Said. + +In granting the preliminary injunction the judge said: + +"Defendants claim generally that the difference in +construction of their apparatus causes the equilibrium or +lateral balance to be maintained and its aerial movement +secured upon an entirely different principle from that +of complainant; the defendants' aeroplanes are curved, +firmly attached to the stanchions and hence are incapable +of twisting or turning in any direction; that the +supplementary planes or so-called rudders are secured to +the forward stanchion at the extreme lateral ends of +the planes and are adjusted midway between the upper +and lower planes with the margins extending beyond the +edges; that in moving the supplementary planes equal +and uniform angles of incidence are presented as +distinguished from fluctuating angles of incidence. Such +claimed functional effects, however, are strongly +contradicted by the expert witness for complainant. + +Similar to Plan of Wrights. + +"Upon this contention it is sufficient to say that the +affidavits for the complainant so clearly define the +principle of operation of the flying machines in question +that I am reasonably satisfied that there is a variableness +of the angle of incidence in the machine of defendants +which is produced when a supplementary plane on one +side is tilted or raised and the other stimultaneously +tilted or lowered. I am also satisfied that the rear +rudder is turned by the operator to the side having the +least angle of incidence and that such turning is done +at the time the supplementary planes are raised +or depressed to prevent tilting or upsetting the machine. +On the papers presented I incline to the view, as already +indicated, that the claims of the patent in suit should be +broadly construed; and when given such construction, +the elements of the Wright machine are found in defendants' +machine performing the same functional result. +There are dissimilarities in the defendants' structure-- +changes of form and strengthening of parts--which may +be improvements, but such dissimilarities seem to me to +have no bearing upon the means adopted to preserve the +equilibrium, which means are the equivalent of the claims +in suit and attain an identical result. + +Variance From Patent Immaterial. + +"Defendants further contend that the curved or arched +surfaces of the Wright aeroplanes in commercial use are +departures from the patent, which describes 'substantially +flat surfaces,' and that such a construction would +be wholly impracticable. The drawing, Fig. 3, however, +attached to the specification, shows a curved line inward +of the aeroplane with straight lateral edges, and considering +such drawing with the terminology of the specification, +the slight arching of the surface is not thought +a material departure; at any rate, the patent in issue +does not belong to the class of patents which requires +narrowing to the details of construction." + +"June Bug" First Infringement. + +Referring to the matter of priority, the judge said: + +"Indeed, no one interfered with the rights of the +patentees by constructing machines similar to theirs until +in July, 1908, when Curtiss exhibited a flying machine +which he called the 'June Bug.' He was immediately +notified by the patentees that such machine with its +movable surfaces at the tips of wings infringed the patent +in suit, and he replied that he did not intend to publicly +exhibit the machine for profit, but merely was engaged +in exhibiting it for scientific purposes as a member +of the Aerial Experiment Association. To this the patentees +did not object. Subsequently, however, the machine, +with supplementary planes placed midway between +the upper and lower aeroplanes, was publicly exhibited +by the defendant corporation and used by Curtiss in +aerial flights for prizes and emoluments. It further appears +that the defendants now threaten to continue such +use for gain and profit, and to engage in the manufacture +and sale of such infringing machines, thereby becoming +an active rival of complainant in the business of +constructing flying machines embodying the claims in suit, +but such use of the infringing machines it is the duty +of this court, on the papers presented, to enjoin. + +"The requirements in patent causes for the issuance +of an injunction pendente lite--the validity of the patent, +general acquiescence by the public and infringement +by the defendants--are so reasonably clear that I believe +if not probable the complainant may succeed at final +hearing, and therefore, status quo should be preserved +and a preliminary injunction granted. + +"So ordered." + +Points Claimed By Curtiss. + +That the Herring-Curtiss Co. will appeal is a certainty. +Mr. Emerson R. Newell, counsel for the company, +states its case as follows: + +"The Curtiss machine has two main supporting surfaces, +both of which are curved * * * and are absolutely +rigid at all times and cannot be moved, warped or +distorted in any manner. The front horizontal rudder is +used for the steering up or down, and the rear vertical +rudder is used only for steering to the right or left, in +the same manner as a boat is steered by its rudder. The +machine is provided at the rear with a fixed horizontal +surface, which is not present in the machine of the patent, +and which has a distinct advantage in the operation +of defendants' machine, as will be hereafter discussed. + +Does Not Warp Main Surface. + +"Defendants' machine does not use the warping of the +main supporting surfaces in restoring the lateral equilibrium, +but has two comparatively small pivoted balancing +surfaces or rudders. When one end of the machine +is tipped up or down from the normal, these planes may +be thrown in opposite directions by the operator, and +so steer each end of the machine up or down to its +normal level, at which time tension upon them is released +and they are moved back by the pressure of the +wind to their normal position. + +Rudder Used Only For Steering. + +"When defendants' balancing surfaces are moved they +present equal angles of incidence to the normal rush +of air and equal resistances, at each side of the machine, +and there is therefore no tendency to turn around a +vertical axis as is the case of the machine of the patent, +consequently no reason or necessity for turning the vertical +rear rudder in defendants' machine to counteract any +such turning tendency. At any rate, whatever may be +the theories in regard to this matter, the fact is that +the operator of defendants' machine does not at any +time turn his vertical rudder to counteract any turning +tendency clue to the side balancing surfaces, but only +uses it to steer the machine the same as a boat is +steered." + +Aero Club Recognizes Wrights. + +The Aero Club of America has officially recognized +the Wright patents. This course was taken following a +conference held April 9th, 1910, participated in by William +Wright and Andrew Freedman, representing the +Wright Co., and the Aero Club's committee, of Philip +T. Dodge, W. W. Miller, L. L. Gillespie, Wm. H. Page +and Cortlandt F. Bishop. + +At this meeting arrangements were made by which +the Aero Club recognizes the Wright patents and will +not give its section to any open meet where the promoters +thereof have not secured a license from the +Wright Company. + +The substance of the agreement was that the Aero +Club of America recognizes the rights of the owners of +the Wright patents under the decisions of the Federal +courts and refuses to countenance the infringement of +those patents as long as these decisions remain in force. + +In the meantime, in order to encourage aviation, both +at home and abroad, and in order to permit foreign +aviators to take part in aviation contests in this country +it was agreed that the Aero Club of America, as the +American representative of the International Aeronautic +Federation, should approve only such public contests +as may be licensed by the Wright Company and that +the Wright Company, on the other hand, should encourage +the holding of open meets or contests where ever approved as +aforesaid by the Aero Club of America +by granting licenses to promoters who make satisfactory +arrangements with the company for its compensation +for the use of its patents. At such licensed meet any +machine of any make may participate freely without +securing any further license or permit. The details and +terms of all meets will be arranged by the committee +having in charge the interests of both organizations. + + + +CHAPTER XXIV. + +HINTS ON PROPELLER CONSTRUCTION. + +Every professional aviator has his own ideas as to the +design of the propeller, one of the most important features +of flying-machine construction. While in many +instances the propeller, at a casual glance, may appear +to be identical, close inspection will develop the fact that +in nearly every case some individual idea of the designer +has been incorporated. Thus, two propellers of the two- +bladed variety, while of the same general size as to +length and width of blade, will vary greatly as to pitch +and "twist" or curvature. + +What the Designers Seek. + +Every designer is seeking for the same result--the +securing of the greatest possible thrust, or air displacement, +with the least possible energy. + +The angles of any screw propeller blade having a +uniform or true pitch change gradually for every increased +diameter. In order to give a reasonably clear +explanation, it will be well to review in a primary way +some of the definitions or terms used in connection with +and applied to screw propellers. + +Terms in General Use. + +Pitch.--The term "pitch," as applied to a screw propeller, +is the theoretical distance through which it would +travel without slip in one revolution, and as applied to +a propeller blade it is the angle at which the blades are +set so as to enable them to travel in a spiral path through +a fixed distance theoretically without slip in one revolution. + +Pitch speed.--The term "pitch speed" of a screw +propeller is the speed in feet multiplied by the number of +revolutions it is caused to make in one minute of time. +If a screw propeller is revolved 600 times per minute, +and if its pitch is 7 ft., then the pitch speed of such a +propeller would be 7x600 revolutions, or 4200 ft. per +minute. + +Uniform pitch.--A true pitch screw propeller is one +having its blades formed in such a manner as to enable +all of its useful portions, from the portion nearest the +hub to its outer portion, to travel at a uniform pitch +speed. Or, in other words, the pitch is uniform when the +projected area of the blade is parallel along its full +length and at the same time representing a true sector +of a circle. + +All screw propellers having a pitch equal to their +diameters have the same angle for their blades at their +largest diameter. + +When Pitch Is Not Uniform. + +A screw propeller not having a uniform pitch, but +having the same angle for all portions of its blades, or +some arbitrary angle not a true pitch, is distinguished +from one having a true pitch in the variation of the pitch +speeds that the various portions of its blades are forced +to travel through while traveling at its maximum pitch +speed. + +On this subject Mr. R. W. Jamieson says in Aeronautics: + +"Take for example an 8-foot screw propeller having an +8-foot pitch at its largest diameter. If the angle is the +same throughout its entire blade length, then all the porions +of its blades approaching the hub from its outer portion would +have a gradually decreasing pitch. The 2-foot +portion would have a 2-foot pitch; the 3-foot portion a 3- +foot pitch, and so on to the 8-foot portion which would +have an 8-foot pitch. When this form of propeller is +caused to revolve, say 500 r.p.m., the 8-foot portion would +have a calculated pitch speed of 8 feet by 500 revolutions, +or 4,000 feet per min.; while the 2-foot portion would +have a calculated pitch speed of 500 revolutions by 2 feet, +or 1,000 feet per minute. + +Effect of Non-Uniformity. + +"Now, as all of the portions of this type of screw +propeller must travel at some pitch speed, which must have +for its maximum a pitch speed in feet below the calculated +pitch speed of the largest diameter, it follows that +some portions of its blades would perform useful work +while the action of the other portions would be negative +--resisting the forward motion of the portions having a +greater pitch speed. The portions having a pitch speed +below that at which the screw is traveling cease to perform +useful work after their pitch speed has been exceeded +by the portions having a larger diameter and a +greater pitch speed. + +"We might compare the larger and smaller diameter +portions of this form of screw propeller, to two power- +driven vessels connected with a line, one capable of traveling +20 miles per hour, the other 10 miles per hour. It +can be readily understood that the boat capable of traveling +10 miles per hour would have no useful effect to +help the one traveling 20 miles per hour, as its action +would be such as to impose a dead load upon the latter's +progress." + +The term "slip," as applied to a screw propeller, is the +distance between its calculated pitch speed and the actual +distance it travels through under load, depending upon +the efficiency and proportion of its blades and the amount +of load it has to carry. + +The action of a screw propeller while performing useful +work might be compared to a nut traveling on a +threaded bolt; little resistance is offered to its forward +motion while it spins freely without load, but give it a +load to carry; then it will take more power to keep up its +speed; if too great a load is applied the thread will strip, +and so it is with a screw propeller gliding spirally on the +air. A propeller traveling without load on to new air +might be compared to the nut traveling freely on the bolt. +It would consume but little power and it would travel at +nearly its calculated pitch speed, but give it work to do +and then it will take power to drive it. + +There is a reaction caused from the propeller projecting +air backward when it slips, which, together with the supporting +effect of the blades, combine to produce useful +work or pull on the object to be carried. + +A screw propeller working under load approaches more +closely to its maximum efficiency as it carries its load +with a minimum amount of slip, or nearing its calculated +pitch speed. + +Why Blades Are Curved. + +It has been pointed out by experiment that certain +forms of curved surfaces as applied to aeroplanes will lift +more per horse power, per unit of square foot, while on +the other hand it has been shown that a flat surface will +lift more per horse power, but requires more area of surface +to do it. + +As a true pitch screw propeller is virtually a rotating +aeroplane, a curved surface may be advantageously employed +when the limit of size prevents using large plane +surfaces for the blades. + +Care should be exercised in keeping the chord of any +curve to be used for the blades at the proper pitch angle, +and in all cases propeller blades should be made rigid so +as to preserve the true angle and not be distorted by +centrifugal force or from any other cause, as flexibility +will seriously affect their pitch speed and otherwise affect +their efficiency. + +How to Determine Angle. + +To find the angle for the proper pitch at any point in +the diameter of a propeller, determine the circumference +by multiplying the diameter by 3.1416, which represent +by drawing a line to scale in feet. At the end of this line +draw another line to represent the desired pitch in feet. +Then draw a line from the point representing the desired +pitch in feet to the beginning of the circumference line. +For example: + +If the propeller to be laid out is 7 feet in diameter, and +is to have a 7-foot pitch, the circumference will be 21.99 +feet. Draw a diagram representing the circumference +line and pitch in feet. If this diagram is wrapped around +a cylinder the angle line will represent a true thread 7 +feet in diameter and 7 feet long, and the angle of the +thread will be 17 3/4 degrees. + +Relation of Diameter to Circumference. + +Since the areas of circles decrease as the diameter +lessens, it follows that if a propeller is to travel at a uniform +pitch speed, the volume of its blade displacement +should decrease as its diameter becomes less, so as to +occupy a corresponding relation to the circumferences of +larger diameters, and at the same time the projected +area of the blade must be parallel along its full length +and should represent a true sector of a circle. + +Let us suppose a 7-foot circle to be divided into 20 +sectors, one of which represents a propeller blade. If the +pitch is to be 7 feet, then the greatest depth of the angle +would be 1/20 part of the pitch, or 4 2/10 inch. If the +line representing the greatest depth of the angle is kept +the same width as it approaches the hub, the pitch will +be uniform. If the blade is set at an angle so its projected +area is 1/20 part of the pitch, and if it is moved +through 20 divisions for one revolution, it would have a +travel of 7 feet. + + + +CHAPTER XXV. + +NEW MOTORS AND DEVICES. + +Since the first edition of this book was printed, early in 1910, +there has been a remarkable advance in the construction of +aeroplane motors, which has resulted in a wonderful decrease +in the amount of surface area from that formerly required. +Marked gain in lightness and speed of the motor has enabled +aviators to get along, in some instances, with one-quarter of +the plane supporting area previously used. The first Wright +biplane, propelled by a motor of 25 h.p., productive of a fair +average speed of 30 miles an hour, had a plane surface of 538 +square feet. Now, by using a specially designed motor of 65 +h. p., capable of developing a speed of from 70 to 80 miles an +hour, the Wrights are enabled to successfully navigate a machine +the plane area of which is about 130 square feet. This +apparatus is intended to carry only one person (the operator). +At Belmont Park, N. Y., the Wrights demonstrated that the +small-surfaced biplane is much faster, easier to manage in the +hands of a skilled manipulator, and a better altitude climber +than the large and cumbersome machines with 538 square feet +of surface heretofore used by them. + +In this may be found a practical illustration of the principle +that increased speed permits of a reduction in plane area in +mathematical ratio to the gain in speed. The faster any object +can be made to move through the air, the less will be the +supporting +surface required to sustain a given weight. But, there +is a limit beyond which the plane surface cannot be reduced +with safety. Regard must always be had to the securing of +an ample sustaining surface so that in case of motor stoppage +there will be sufficient buoyancy to enable the operator to +descend safely. + +The baby Wright used at the Belmont Park (N. Y.) aviation +meet in the fall of 1910, had a plane length of 19 feet 6 inches, +and an extreme breadth of 21 feet 6 inches, with a total surface +area of 146 square feet. It was equipped with a new Wright +8-cylinder motor of 60 h. p., and two Wright propellers of 8 +feet 6 inches diameter and 500 r. p. m. It was easily the fastest +machine at the meet. After the tests, Wilbur Wright said: + +"It is our intention to put together a machine with specially +designed propellers, specially designed gears and a motor which +will give us 65 horsepower at least. We will then be able, +after some experimental work we are doing now, to send forth +a machine that will make a new speed record." + +In the new Wright machines the front elevating planes for +up-and-down control have been eliminated, and the movements +of the apparatus are now regulated solely by the rear, or +"tail" +control. + +A Powerful Light Motor. + +Another successful American aviation motor is the aeromotor, +manufactured by the Detroit Aeronautic Construction. +Aeromotors are made in four models as follows: + +Model 1.--4-cylinder, 30-40 h. p., weight 200 pounds. + +Model 2.--4-cylinder, (larger stroke and bore) 40-50 h. p., +weight 225 pounds. + +Model 3.--6-cylinder. 50-60 h. p., weight 210 pounds. + +Model 4.--6-cylinder, 60-75 h. p., weight 275 pounds. + +This motor is of the 4-cycle, vertical, water-cooled type. +Roberts Aviation Motor. + +One of the successful aviation motors of American make, is +that produced by the Roberts Motor Co., of Sandusky, Ohio. +It is designed by E. W. Roberts, M. E., who was formerly +chief assistant and designer for Sir Hiram Maxim, when the +latter was making his celebrated aeronautical experiments in +England in 1894-95. This motor is made in both the 4- and +6-cylinder forms. The 4-cylinder motor weighs complete with +Bosch magneto and carbureter 165 pounds, and will develop +40 actual brake h. p. at 1,000 r. p. m., 46 h. p. at 1,200 and 52 +h. p. at 1,400. The 6-cylinder weighs 220 pounds and will +develop 60 actual brake h. p. at 1,000 r. p. m., 69 h. p. at +1,200 and 78 h. p. at 1,500. + +Extreme lightness has been secured by doing away with all +superfluous parts, rather than by a shaving down of materials +to a dangerous thinness. For example, there is neither an intake +or exhaust manifold on the motor. The distributing valve +forms a part of the crankcase as does the water intake, and +the gear pump. Magnalium takes the place of aluminum in +the crankcase, because it is not only lighter but stronger and +can be cast very thin. The crankshaft is 2 1/2-inch diameter +with a 2 1/4-inch hole, and while it would be strong enough in +ordinary 40 per cent carbon steel it is made of steel twice the +strength of that customarily employed. Similar care has been +exercised on other parts and the result is a motor weighing 4 +pounds per h. p. + +The Rinek Motor. + +The Rinek aviation motor, constructed by the Rinek Aero +Mfg. Co., of Easton, Pa., is another that is meeting with favor +among aviators. Type B-8 is an 8-cylinder motor, the cylinders +being set at right angles, on a V-shaped crank case. It is water +cooled, develops 50-60 h. p., the minimum at 1,220 r. p. m., and +weighs 280 pounds with all accessories. Type B-4, a 4-cylinder +motor, develops 30 h. p. at 1,800 r. p. m., and weighs 130 pounds +complete. The cylinders in both motors are made of cast iron +with copper water jackets. + +The Overhead Camshaft Boulevard. + +The overhead camshaft Boulevard is still another form of +aviation motor which has been favorably received. This is +the product of the Boulevard Engine Co., of St. Louis. It is +made with 4 and 8 cylinders. The former develops 30-35 h. p. +at 1,200 r. p. m., and weighs 130 pounds. The 8-cylinder motor +gives 60-70 h. p. at 1,200 r. p. m., and weighs 200 pounds. +Simplicity of construction is the main feature of this motor, +especially in the manipulation of the valves. + + + +CHAPTER XXVI. + +MONOPLANES, TRIPLANES, MULTIPLANES. + +Until recently, American aviators had not given serious +attention to any form of flying machines aside from biplanes. +Of the twenty-one monoplanes competing at the International +meet at Belmont Park, N. Y., in November, 1910, only three +makes were handled by Americans. Moissant and Drexel +navigated Bleriot machines, Harkness an Antoinette, and +Glenn Curtiss a single decker of his own construction. On +the other hand the various foreign aviators who took part in +the meet unhesitatingly gave preference to monoplanes. + +Whatever may have been the cause of this seeming prejudice +against the monoplane on the part of American air sailors, +it is slowly being overcome. When a man like Curtiss, who +has attained great success with biplanes, gives serious attention +to the monoplane form of construction and goes so far as +to build and successfully operate a single surface machine, +it may be taken for granted that the monoplane is a fixture in +this country. + +Dimensions of Monoplanes. + +The makes, dimensions and equipment of the various monoplanes +used at Belmont Park are as follows: + +Bleriot--(Moissant, operator)--plane length 23 feet, extreme +breadth 28 feet, surface area 160 square feet, 7-cylinder, 50 h. +p. +Gnome engine, Chauviere propeller, 7 feet 6 inches diameter, +1,200 r. p. m. + +Bleriot--(Drexel, operator)--exactly the same as Moissant's +machine. + +Antoinette--(Harkness, operator)--plane length 42 feet, +extreme breadth 46 feet, surface area 377 square feet, Emerson +6-cylinder, 50 h. p. motor, Antoinette propeller, 7 feet 6 inches +diameter, 1,200 r. p. m. + +Curtiss--(Glenn H. Curtiss, operator)--plane length 25 feet, +extreme breadth 26 feet, surface area 130 square feet, Curtiss +8-cylinder, 60 h. p. motor, Paragon propeller, 7 feet in +diameter, 1,200 r. p. m. + +With one exception Curtiss had the smallest machine of +any of those entering into competition. The smallest was La +Demoiselle, made by Santos-Dumont, the proportions of which +were: plane length 20 feet, extreme breadth 18 feet, surface +area 100 square feet, Clement-Bayard 2-cylinder, 30 h. p. motor, +Chauviere propeller, 6 feet 6 inches in diameter, 1,100 r. p. m. + +Winnings Made with Monoplanes. + +Operators of monoplanes won a fair share of the cash prizes. +They won $30,283 out of a total of $63,250, to say nothing about +Grahame-White's winnings. The latter won $13,600, but part +of his winning flights were made in a Bleriot monoplane, and +part in a Farman machine. Aside from Grahame-White the +winnings were divided as follows: Moissant (Bleriot) $13,350; +Latham (Antoinette) $8,183; Aubrun (Bleriot) $2,400; +De Lesseps (Bleriot) $2,300; Drexel (Bleriot) $1,700; Radley +(Bleriot) $1,300; Simon (Bleriot) $750; Andemars (Clement- +Bayard) $100; Barrier (Bleriot) $100. + +Out of a total of $30,283, operators of Bleriot machines won +$21,900, again omitting Grahame-White's share. If the winnings +with monoplane and biplane could be divided so as to +show the amount won with each type of machine the credit +side of the Bleriot account would be materially enlarged. + +The Most Popular Monoplanes. + +While the number of successful monoplanes is increasing +rapidly, and there is some feature of advantage in nearly all +the new makes, interest centers chiefly in the Santos-Dumont, +Antoinette and Bleriot machines. This is because more has +been accomplished with them than with any of the others, +possibly because they have had greater opportunities. + +For the guidance of those who may wish to build a machine +of the monoplane type after the Santos-Dumont or Bleriot +models, the following details will be found useful. + +Santos-Dumont--The latest production of this maker is +called the "No. 20 Baby." It is of 18 feet spread, and 20 feet +over all in depth. It stands 4 feet 2 inches in height, not +counting the propeller. When this latter is in a vertical +position +the extreme height of the machine is 7 feet 5 inches. It +is strictly a one-man apparatus. The total surface area is 115 +square feet. The total weight of the monoplane with engine +and propeller is 352 pounds. Santos-Dumont weighs 110 +pounds, so the entire weight carried while in flight is 462 +pounds, or about 3.6 pounds per square foot of surface. + +Bamboo is used in the construction of the body frame, and +also for the frame of the tail. The body frame consists of +three bamboo poles about 2 inches in diameter at the forward +end and tapering to about 1 inch at the rear. These poles are +jointed with brass sockets near the rear of the main plane so +they may be taken apart easily for convenience in housing or +transportation. The main plane is built upon four transverse +spars of ash, set at a slight dihedral angle, two being placed on +each side of the central bamboo. These spars are about 2 inches +wide by 1 1/8-inch deep for a few feet each side of the center of +the machine, and from there taper down to an inch in depth +at the center bamboo, and at their outer ends, but the width +remains the same throughout their entire length. The planes +are double surfaced with silk and laced above and below the +bamboo ribs which run fore and aft under the main spars and +terminate in a forked clip through which a wire is strung for +lacing on the silk. The tail consists of a horizontal and +vertical +surface placed on a universal joint about 10 feet back of +the rear edge of the main plane. Both of these surfaces are +flat and consist of a silk covering stretched upon bamboo ribs. +The horizontal surface is 6 feet 5 inches across, and 4 feet 9 +inches from front to back. The vertical surface is of the same +width (6 feet 5 inches) but is only 3 feet 7 inches from front +to back. All the details of construction are shown in the +accompanying illustration. + +Power is furnished by a very light (110 pounds) Darracq +motor, of the double-opposed-cylinder type. It has a bore of +4.118 inches, and stroke of 4.724 inches, runs at 1,800 r. p. m., +and with a 6 1/2-foot propeller develops a thrust of 242 1/2 +pounds +when the monoplane is held steady. + +Bleriot--No. XI, the latest of the Bleriot productions, and +the greatest record maker of the lot, is 28 feet in spread of +main +plane, and depth of 6 feet in largest part. This would give a +main surface of 168 square feet, but as the ends of the plane +are sharply tapered from the rear, the actual surface is reduced +to 150 square feet. Projecting from the main frame is an +elongated tail (shown in the illustration) which carries the +horizontal and vertical rudders. The former is made in three +sections. The center piece is 6 feet 1 inch in spread, and 2 feet +10 inches in depth, containing 17 square feet of surface. The +end sections, which are made movable for warping purposes, +are each 2 feet 10 inches square, the combined surface area in +the entire horizontal rudder being 33 square feet. The vertical +rudder contains 4 1/2 square feet of surface, making the entire +supporting area 187 1/2 square feet. + +From the outer end of the propeller shaft in front to the extreme +rear edge of the vertical rudder, the machine is 25 feet +deep. Deducting the 6-foot depth of the main plane leaves 19 +feet as the length of the rudder beam and rudders. The motor +equipment consists of a 3-cylinder, air-cooled engine of about +30 h. p. placed at the front end of the body frame, and carrying +on its crankshaft a two-bladed propeller 6 feet 8 inches in +diameter. The engine speed is about 1,250 r. p. m. at which +the propeller develops a thrust of over 200 pounds. + +The Bleriot XI complete weighs 484 pounds, and with +operator and fuel supply ready for a 25- or 30-mile flight, 715 +pounds. One peculiarity of the Bleriot construction is that, +while the ribs of the main plane are curved, there is no +preliminary +bending of the pieces as in other forms of construction. +Bleriot has his rib pieces cut a little longer than required +and, by springing them into place, secures the necessary +curvature. A good view of the Bleriot plane framework is +given on page 63. + +Combined Triplane and Biplane. + +At Norwich, Conn., the Stebbins-Geynet Co., after several +years of experiment, has begun the manufacture of a combination +triplane and biplane machine. The center plane, which is +located about midway between the upper and lower surfaces, +is made removable. The change from triplane to biplane, or +vice versa, may be readily made in a few minutes. The +constructors +claim for this type of air craft a large supporting +surface area with the minimum of dimensions in planes. Although +this machine has only 24-foot spread and is only 26 +feet over all, its total amount of supporting area is 400 square +feet; weight, 600 pounds in flying order, and lifting capacity +approximately 700 pounds more. + +The frame is made entirely of a selected grade of Oregon +spruce, finished down to a smooth surface and varnished. All +struts are fish-shaped and set in aluminum sockets, which are +bolted to top and lower beams with special strong bolts of +small diameter. The middle plane is set inside the six uprights +and held in place by aluminum castings. A flexible twisted +seven-strand wire cable and Stebbins-Geynet turnbuckles are +used for trussing. + +The top plane is in three sections, laced together. It has a +24-foot spread and is 7 feet in depth. The middle plane is in +two sections each of 7 1/2 feet spread and 6 feet in depth. The +center ends of the middle plane sections do not come within +5 feet of joining, this open space being left for the engine. +The bottom plane is of 16 feet spread and 5 feet in depth. It +will thus be seen that the planes overhang one another in depth, +the bottom one being the smallest in this respect. The planes +are set at an angle of 9 degrees, and there is a clear space of 3 +1/2 feet between each, making the total distance from the bottom +to the top plane a trifle over 7 feet. The total supporting +surface in the main planes is 350 square feet. By arranging the +three plane surfaces at an angle as described and varying their +size, the greatest amount of lifting area is secured above the +center of gravity, and the greatest weight carried below. + +The ribs are made of laminated spruce, finished down to +1/2x3/4-inch cross section dimensions, with a curvature of about +1 in 20, and fastened to the beams with special aluminum +castings. +Number 2 Naiad aeroplane cloth is used in covering the +planes, with pockets sewn in for the ribs. + +Two combination elevating rudders are set up well in front, +each having 18 square feet of supporting area. These rudders +are arranged to work in unison, independently, or in opposite +directions. In the Model B machine, there are also two small +rear elevating rudders, which work in unison with the front +rudders. One vertical rudder of 10 square feet is suspended +in the rear of a small stationary horizontal plane in Model A, +while the vertical rudder on Model B is only 6 square feet in +size. The elevating rudders are arranged so as to act as +stabilizing +planes when the machine is in flight. The wing tips are +held in place with a special two-piece casting which forms a +hinge, and makes a quick detachable joint. Wing tips are also +used in balancing. + +Model A is equipped with a Cameron 25-30 h. p., 4-cylinder, +air-cooled motor. On Model B a Holmes rotary 7-cylinder +motor of 4x4-inch bore and stroke is used. + +Positive control is secured by use of the Stebbins-Geynet +"auto-control" system. A pull or push movement operates the +elevating rudders, while the balancing is done by means of +side movements or slight turns. The rear vertical rudder is +manipulated by means of a foot lever. + +New Cody Biplane. + +Among the comparatively new biplanes is one constructed by +Willard F. Cody, of London, Eng., the principal distinctive +feature of which is an automaticcontrol which works independently +of the hand levers. For the other control a long lever +carrying a steering wheel furnishes all the necessary control +movements, there being no footwork at all. The lever is +universally jointed and when moved fore and aft operates the +two ailerons as if they were one; when the shaft is rotated it +moves the tail as a whole. The horizontal tail component is +immovable. When the lever is moved from side to side it works +not only the ailerons and the independent elevators, but also +through a peculiar arrangement, the vertical rear rudder as well. + +The spread of the planes is 46 feet 6 inches and the width 6 +feet 6 inches. The ailerons jut out 1 foot 6 inches on each +side of the machine and are 13 feet 6 inches long. The cross- +shaped tail is supported by an outrigger composed of two long +bamboos and of this the vertical plane is 9 feet by 4 feet, while +the horizontal plane is 8 feet by 4 feet. The over-all length +of the machine is 36 feet. The lifting surface is 857 square +feet. It will weigh, with a pilot, 1,450 pounds. The distance +between the main planes is 8 feet 6 inches, which is a rather +notable feature in this flyer. + +The propeller has a diameter of 11 feet and 2 inches with a +13-foot 6-inch pitch; it is driven at 560 revolutions by a chain, +and the gear reduction between the chain and propeller shaft +is two to one. + +The machine from elevator to tail plane bristles in original +points. The hump in the ribs has been cut away entirely, so +that although the plane is double surfaced, the surfaces are +closest together at a point which approximates the center of +pressure. The plane is practically of two stream-line forms, +of which one is the continuation of the other. This construction, +claims the inventor, will give increased lift, and decreased +head resistance. The trials substantiate this, as the angle of +incidence in flying is only about one in twenty-six. + +The ribs in the main planes are made of strips of silver spruce +one-half by one-half inch, while those in the ailerons are solid +and one-fourth inch thick. In the main planes the fabric is +held down with thin wooden fillets. Cody's planes are noted +for their neatness, rigidity and smoothness. Pegamoid fabric +is used throughout. + +Pressey Automatic Control. + +Another ingenious system of automatic control has been +perfected by Dr. J. B. Pressey, of Newport News, Va. The +aeroplane is equipped with a manually operated, vertical rudder, +(3), at the stern, and a horizontal, manually operated, +front control, (4), in front. At the ends of the main plane, and +about midway between the upper and lower sections thereof, +there are supplemental planes, (5). + +In connection with these supplemental planes (5), there is +employed a gravity influenced weight, the aviator in his seat, +for holding them in a horizontal, or substantially horizontal, +position when the main plane is traveling on an even keel; and +for causing them to tip when the main plane dips laterally, to +port or starboard, the planes (5) having a lifting effect upon +the +depressed end of the main plane, and a depressing effect upon +the lifted end of the main plane, so as to correct such lateral +dip +of the main plane, and restore it to an even keel. To the +forward, +upper edge of planes (5) connection is made by means +of rod (13) to one arm of a bellcrank lever, (14) the latter +being +pivotally mounted upon a fore and aft pin (15), supported from +the main plane; and the other arms of the port and starboard +bellcrank levers (16), are connected by rod (17), which has an +eye (18), for receiving the segmental rod (19), secured to and +projecting from cross bar on seat supporting yoke (7). When, +therefore, the main plane tips downwardly on the starboard +side, the rod (17) will be moved bodily to starboard, and the +starboard balancing plane (5) will be inclined so as to raise its +forward edge and depress its rear edge, while, at the same time, +the port balancing plane (5), will be inclined so as to depress +its forward edge, and raise its rear edge, thereby causing the +starboard balancing plane to exert a lifting effect, and the port +balancing plane to exert a depressing effect upon the main +plane, with the result of restoring the main plane to an even +keel, at which time the balancing planes (5), will have resumed +their normal, horizontal position. + +When the main plane dips downwardly on the port side, a +reverse action takes place, with the like result of restoring the +main plane to an even keel. In order to correct forward and +aft dip of the main plane, fore and aft balancing planes (20) +and (23) are provided. These planes are carried by transverse +rock shafts, which may be pivotally mounted in any suitable +way, upon structures carried by main plane. In the present +instance, the forward balancing plane is pivotally mounted in +extensions (21) of the frame (22) which carries the forward, +manually operated, horizontal ascending and descending plane + +It is absolutely necessary, in making a turn with an aeroplane, +if that turn is to be made in safety, that the main plane shall +be inclined, or "banked," to a degree proportional to the +radius +of the curve and to the speed of the aeroplane. Each different +curve, at the same speed, demands a different inclination, as is +also demanded by each variation in speed in rounding like +curves. This invention gives the desired result with absolute +certainty. + +The Sellers' Multiplane. + +Another innovation is a multiplane, or four-surfaced machine, +built and operated by M. B. Sellers, formerly of Grahn, Ky., +but now located at Norwood, Ga. Aside from the use of four +sustaining surfaces, the novelty in the Sellers machine lies in +the fact that it is operated successfully with an 8 h. p. motor, +which is the smallest yet used in actual flight. In describing +his work, Mr. Sellers says his purpose has been to develop the +efficiency of the surfaces to a point where flight may be +obtained +with the minimum of power and, judging by the results +accomplished, he has succeeded. In a letter written to the +authors of this book, Mr. Sellers says: + +"I dislike having my machine called a quadruplane, because +the number of planes is immaterial; the distinctive feature being +the arrangement of the planes in steps; a better name would +be step aeroplane, or step plane. + +"The machine as patented, comprises two or more planes +arranged in step form, the highest being in front. The machine +I am now using has four planes 3 ft. x 18 ft.; total about 200 +square feet; camber (arch) 1 in 16. + +"The vertical keel is for lateral stability; the rudder for +direction. This is the first machine (so far as I know) to have a +combination of wheels and runners or skids (Oct. 1908). The +wheels rise up automatically when the machine leaves the +ground, so that it may alight on the runners. + +"A Duthirt & Chalmers 2-cylinder opposed, 3 1/8-inch engine +was used first, and several hundred short flights were made. +The engine gave four brake h. p., which was barely sufficient +for continued flight. The aeroplane complete with this engine +weighed 78 pounds. The engine now used is a Bates 3 5/8-inch, +2-cylinder opposed, showing 8 h. p., and apparently giving +plenty of power. The weight of aeroplane with this engine is +now 110 pounds. Owing to poor grounds only short flights +have been made, the longest to date (Dec. 31, 1910) being about +1,000 feet. + +"In building the present machine, my object was to produce a +safe, slow, light, and small h. p. aeroplane, a purpose which I +have accomplished." + + + +CHAPTER XXVII. + +1911 AEROPLANE RECORDS. + +THE WORLD AT LARGE. + +Greatest Speed Per Hour, Whatever Length of Flight, Aviator +Alone--E. Nieuport, Mourmelon, France, June 21, Nieuport Machine, +82.72 miles; with one passenger, E. Nieuport, Moumlelon, France, +June 12, Nieuport Machine, 67.11 miles; with two passengers, E. +Nieuport, Mourmelon, France, March 9, Nieuport Machine, 63.91 +miles; with three passengers, G. Busson, Rheims, France, March +10, Deperdussin Machine, 59.84 miles; with four passengers, G. +Busson, Rheims, France, March 10, Deperdussin Machine, 54.21 +miles. + +Greatest Distance Aviator Alone--G. Fourny, no stops, Buc, +France, September 2, M. Farman Machine, 447.01 miles; E. Helen, +three stops, Etampes, France, September 8, Nieuport Machine, +778.45 miles; with one passenger, Lieut. Bier, Austria, October +2, Etrich Machine, 155.34 miles; with two passengers, Lieut. +Bier, Austria, October 4, Etrich Machine, 69.59 miles; with three +passengers, G. Busson, Rheims, France, March 10, Deperdussin +Machine, 31.06 miles; with four passengers, G. Busson, Rheims, +France, March 10, Deperdussin Machine, 15.99 miles. + +Greatest Duration Aviator Alone--G. Fourny, no stops, Buc, +France, September 2, M. Farman Machine, 11 hours, 1 minute, 29 +seconds, E. Helen, three stops, Etampes, France, September 8, +Nieuport Machine, 14 hours, 7 minutes, 50 seconds, 13 hours, 17 +minutes net time; with one passenger, Suvelack, Johannisthal, +Germany, December 8, 4 hours, 23 minutes; with two passengers, T. +de W. Milling, Nassau Boulevard, New York, September 26, +Burgess-Wright Machine, 1 hour, 54 minutes, 42 3-5 seconds; with +three passengers, Warchalowski, Wiener-Neustadt, Aust., October +30, 45 minutes, 46 seconds; with four passengers, G. Busson, +Rheims, France, March 10, Deperdussin Machine, 17 minutes, 28 1-5 +seconds. + +Greatest Altitude Aviator Alone--Garros, St. Malo, France, +September 4, Bleriot Machine, 13,362 feet; with one passenger, +Prevost, Courcy, France, December 2, 9,840 feet; with two +passengers, Lieut. Bier, Austria, Etrich Machine, 4,010 feet. + +AMERICAN RECORDS. + +Greatest Speed Per Hour, Whatever Length of Flight, Aviator +Alone--A. Leblanc, Belmont Park, N. Y., October 29, Bleriot +Machine, 67.87 miles; with one passenger, C. Grahame-White, +Squantum, Mass., September 4, Nieuport Machine, 63.23 miles; with +two passengers, T. O. M. Sopwith, Chicago, Ill., August 15, +Wright Machine, 34.96 miles. + +Greatest Distance Aviator Alone--St. Croix Johnstone, Mineola, +N. Y., July 27, Moisant (Bleriot Type) Machine, 176.23 miles. + +Greatest Duration Aviator Alone--Howard W. Gill, Kinloch, Mo., +October 19, Wright Machine, 4 hours, 16 minutes, 35 seconds; with +one passenger, G. W. Beatty, Chicago, Ill., August 19, Wright +Machine, 3 hours, 42 minutes, 22 1-5 seconds; with two +passengers, T. de W. Milling, Nassau Boulevard, N. Y., September +26, Burgess-Wright Machine, 1 hour, 54 minutes, 42 3-5 seconds. + +Greatest Altitude Aviator Alone--L. Beachy, Chicago, Ill., August +20, Curtiss Machine, 11,642 feet; with one passenger, C. Grahame- +White, Nassau Boulevard, N. Y., September 30, Nieuport Machine, +3,347 feet. + +Weight Carrying--P. O. Parmelee, Chicago, III., August 19, +Wright Machine, 458 lbs. + +AVIATION DEVELOPMENT. + +The wonderful progress made in the science of aviation +during the year 1911 far surpasses any twelve months' advancement +recorded. The advancement has not been confined to any country or +continent, since every part of the world is taking its part in +aviation history making. + +The rapidly increasing interest in aviation has brought +forth schools for the instruction of flying in both the old and +new world, and licensed air pilots before they receive their +sanctions from the governing aero clubs of their country are +required to pass an extremely trying examination in actual +flights. Exhibition flights and races were common in all +parts of the world during 1911, and touring aviators visited +India, China, Japan, South Africa, Australia and South +America, giving exhibitions and instruction. + +Europe was the scene of a number of cross-country races +in which entries ranging from ten to twenty aviators flew +from city to city around a given circuit, which in some +instances exceeded 1,000 miles in distance. Cross-country +flights with and without passengers became so common that +those of less than two hours' duration attracted little +attention. There were fewer attempts at high altitude soaring, +although the world's record in this department of aviation +was bettered several times. In place of these high flights, the +aviators devoted more attention to speed, duration and +spectacular manoeuvres, which appeared to satisfy the spectators. +The prize money won during 1911 exceeded $1,000,000, but +owing to the increased number of aviators the individual +winnings were not as large as in 1910. + +It is estimated that within the past twelve months more +than 300,000 miles have been covered in aeroplane flights +and more than seven thousand persons, classed either as +aviators or passengers, taken up into the air. The aeroplane +of today ranges through monoplane, biplane, triplane and +even quadraplane, and more than two hundred types of these +machines are in use. + +Aeroplanes are becoming a factor of international commerce. +The records of the Bureau of Statistics show that +more than $50,000 worth of aeroplanes were imported into, +and exported from, the United States in the months of July, +August and September, 1911. The Bureau of Statistics only +began the maintenance of a separate record of this comparatively +new article of commerce with the opening of the fiscal +year 1911-12. + +Two of the prominent developments of 1911 were the +introduction of the hydro-aeroplane and the motorless glider +experiments of the Wright brothers at Killdevil Hills, N. C., +where during the two weeks' experiments numerous flights +with and against the wind were made, culminating in the +establishing of a record by Orville Wright on October 25, +1911, when in a 52-mile per hour blow he reached an elevation +of 225 feet and remained in the air 10 minutes and 34 +seconds. The search for the secret of automatic stability +still continues, and though some remarkable progress has +been made the solution has not yet been reached. + +NOTABLE CROSS-COUNTRY FLIGHTS OF 1911. + +One of the important features of 1911 in aviation was the +rapid increase in the number and distance of cross-country +flights made either for the purpose of exhibition, testing, +instruction or pleasure. Flights between cities in almost every +country of the world became common occurrences. So great +was the number that only those of more than ordinary importance +because of speed, distance or duration are recorded. +The flights of Harry N. Atwood from Boston to Washington +and from St. Louis to New York, and C. P. Rodgers from +New York to Los Angeles were the most important events +of the kind in this country. The St Louis to New York flight +was a distance by air route, 1,266 miles. Duration of flight, +12 days. Net flying time, 28 hours 53 minutes. Average +daily flight, 105.5 miles. Average speed, 43.9 miles per hour. + +Transcontinental Flight of Calbraith P. Rodgers.--All +world records for cross-country flying were broken during +the New York to Los Angeles flight of Calbraith P. Rodgers, +who left Sheepshead Bay, N. Y., on Sunday, September 17, +1911, and completed his flight to the Pacific Coast on Sunday, +November 5, at Pasadena, Cal. Rodgers flew a Wright biplane, +and during his long trip the machine was repeatedly +repaired, so great was the strain of the long journey in the +air. Rodgers is estimated to have covered 4,231 miles, +although the actual route as mapped out was but 4,017 miles. +Elapsed time to Pasadena, Cal., 49 days; actual time in the +air, 4,924 minutes, equivalent to 3 days 10 hours 4 minutes; +average speed approximating 51 miles per hour. Rodgers' +longest flight in one day was from Sanderson to Sierra Blanca, +Texas, on October 28, when he covered 231 miles. On November +12, Rodgers fell at Compton, Cal., and was badly injured, +causing a delay of 28 days. + +European Circuit Race.--Started from Paris on June 18, +1911. Distance, 1,073 miles, via Paris to Liege; Liege to Spa +to Liege; Liege to Utrecht, Holland; Utrecht to Brussels, +Belgium; Brussels to Roubaix; Roubaix to Calais; Calais to +London; London to Calais and Calais to Paris. Three aeronauts +were killed either at the start or shortly after the race +was in progress. They were Capt. Princetau, M. Le Martin +and M. Lendron. Three others were injured by falls. Seven +hundred thousand spectators witnessed the start from the +aviation field at Vincennes, near Paris. There were more +than forty starters, of which eight finished. The winner, Lieut. +Jean Conneau, who flies under the name of "Andre Beaumont," +completed the circuit on July 7; his actual net flying time for +the distance being 58h. 38m. 4-5s. + +Circuit of England Race--1,010 Miles in Five Sections.-- + +Start, July 22. Finish, July 26. Prize, $50,000. Twenty- +eight entries and eighteen starters. Seventeen finished the +first section from Brooklands to Hendon, a distance of twenty +miles. Five reached Edinburgh, the second section, a distance +of 343 miles, and four completed the entire circuit. + +Paris to Madrid Race.--This race was started at the Paris +aviation held at Issy-les-Moulineaux on Sunday, May 21. There +were twenty-one entrants, and fully 300,000 spectators gathered +to witness the initial flight of the aerial races. The race +was divided into three stages as follows: Paris to Angouleme, +248 miles; Angouleme to St. Sebastian, 208 miles, and from +St. Sebastian to Madrid, 386 miles, a total distance of 842 +miles. After three of the entrants had safely left the field, +Aviator Train lost control of his plane, and in falling struck +and killed M. Berteaux, the French Minister of War, and +seriously injured Premier Monis. The accident caused the +withdrawal of all but six of the original entrants, and of these +but one finished. The race called for a flight over the +Pyrenees Mountains, and Vedrines, the winner, had to rise +to a height of more than 7,000 feet to pass the mountain +barrier near Somosierra Pass. Both Vedrines and Gibert, another +competitor, were attacked by eagles during the latter +stages of the flight. Vedrines, who started from Paris on +Monday, May 22, finished the long and perilous race at 8:06 +a. m. Friday, May 26. Vedrines net flying time, all controls +and enforced stops subtracted, was 14h. 55m. 18s. The various +prizes to the winner aggregated $30,000. + +The Paris-Rome-Turin Race.--The conditions of this race +called for a flight between the cities of Paris, Rome and +Turin, covering a distance of 1,300 miles. The aviators were +permitted by the rules to alight whenever and wherever they +desired and the time limit was set from May 28 to June 15. +A prize of $100,000 was offered the winner, but the contest +was never finished, as one after another the aviators dropped +out until Frey fell near Roncigilione, France, breaking both +arms and legs and unofficially ending the contest. There +were twenty-one entries and twelve actual starters. + +International Speed Cup Race.--The third annual international +James Gordon Bennett speed cup race was held at +Eastchurch, England, on July 1, 1911, and for the second +time was won by an American aviator, C. T. Weymann, in a +French racing aeroplane. The distance was 150 kilometres +equivalent to 94 miles, and the winner's time of 1h. 11m. 36s. +showed an average speed of 78.77 miles per hour. The first +race was held in 1909 and was won by Glenn Curtiss, who +flew the twenty kilometres (12.4 miles) in 15 minutes 50 2-5 +seconds at an average speed of 47 miles per hour. In 1910 +the winner was Grahame-White, who covered 100 kilometres +(62 miles) at Belmont Park, L. I., in 60 minutes 47 3-5 seconds, +an average speed of 61.3 miles per hour. In the 1911 +race there were six starters: three from France, two from +Great Britain and one from the United States. + +Milan to Turin to Milan Race.--This race which was +started from Milan, Italy, on October 29, was restricted to +Italian aviators and had six starters. The distance was +approximately 177 miles and won by Manissero in a Bleriot +machine in 3h. 16m. 2 4-5s. + +New York to Philadelphia Race.--The first intercity aeroplane +race ever held in the United States was started from +New York City on August 5, and finished in Philadelphia the +same day. The prize of $5,000 was offered by a commercial +concern with stores in the two cities: Three entrants competed +from the Curtiss Exhibition Company. The distance +was approximately 83 miles and won by L. Beachey in a +Curtiss machine in 1h. 50m. at an average speed of 45 miles +per hour. + +Tri-State Race.--The tri-state race was the feature event +of the Harvard Aviation Society meet held at Squantum, +Mass., August 26 to September 6. It was held Labor Day, +September 4, over a course of 174 miles, from Boston to +Nashua to Worcester to Providence to Boston. Four competitors +started, of which two finished, the winner, E. Ovington, +in a Bleriot machine. Ovington's net flying time, 3h. 6m. +22 1-5s. Winner's prize, $10,000. + +AEROPLANES AND DIRIGIBLE BALLOONS IN WARFARE. + +Wonderful progress has been made in the development of +the aeroplane in this country and in Europe since 1903, and +within the last two or three years the leading powers of the +world have entered upon extensive tests and experiments to +determine its availability and usefulness in land and naval +warfare. + +At the present time all the great powers are building or +purchasing aeroplanes on an extensive scale. They have +established government schools for the instruction of their +army and navy officers and for experimental work. So-called +"Airship Fleets" have been constructed and placed in commission +as auxiliaries to the armies and navies. The fleets +of France and Germany are about equal and are larger by +far than those of any of the other powers. The length of the +dirigibles composing these fleets runs from 150 to 500 feet; +they are equipped with engines of from 50 to 500 horse-power, +with a rate of speed ranging from 20 to 30 miles per hour. +Their approximate range is from 200 to 900 miles; the longest +actual run (made by the Zeppelin II, Germany) is 800 miles. + +A British naval airship, one of the largest yet built, was +completed last summer. It has cost over $200,000, and it was +in course of designing and construction two years. It is 510 +feet long; can carry 22 persons, and has a lift of 21 tons. + +The relative value of the dirigible balloon and the aeroplane +in actual war is yet to be determined. The dirigible +is considered to be the safer, yet several large balloons of this +class in Germany and France have met with disaster, involving +loss of lives. The capacity of the dirigible for longer +flights and its superior facilities for carrying apparatus and +operators for wireless telegraphy are distinct advantages. + +There has not yet been much opportunity to test the airship +in actual warfare. The aeroplane has been used by the +Italians in Tripoli for scouting and reconnoitering and is said +to have justified expectations. On several occasions the Italian +military aviators followed the movements of the enemy, in +one instance as far as forty miles inland. At the time of the +attack by the Turks a skillful aeroplane reconnaissance revealed +the approach of a large Turkish force, believed to be at +the time sixty miles away in the mountains. + +Aeroplanes and airships, as they exist today, would doubtless +render very valuable service in a time of war, both over +land and water, in scouting, reconnoitering, carrying dispatches, +and as some experts believe, in locating submarines +and mines placed by the enemy in channels of exits from ports. +A "coast aeroplane" could fly out 30 or 40 miles from land. +and rising to a great height, descry any hostile ships on the +distant horizon, observe their number, strength, formation and +direction, and return within two hours with a report to obtain +which would require several swift torpedo-boat destroyers +and a much greater time. The question as to whether it +would be practicable to bombard an enemy on land or sea +with explosive bombs dropped or discharged from flying machines +or airships, is one which is much discussed but hardly +yet determined. + +Aeroplanes have been constructed with floats in the place +of runners and several attempts have been made, in some +cases successfully, to light with them on and to rise from the +water. Mr. Curtiss did this at San Francisco, in January, +1911. Attempts have also been made with the aeroplane to +alight on and to take flight from the deck of a warship. Toward +the end of 1910 Aviator Ely flew to land from the +cruiser Birmingham, and in January, 1911, he flew from land +and alighted on the cruiser Pennsylvania. But in these cases +special arrangements were made which would be hardly practicable +in a time of actual war. + +In November, 1911, a test was made at Newport, R. I., by +Lieut. Rodgers, of the navy, of a "hydro-areoplane" as an +auxiliary to a battleship. The idea of the test was to alight +alongside of the ship, hoist the machine aboard, put out to sea +and launch the machine again with the use of a crane. Lieut. +Rodgers came down smoothly alongside the Ohio, his machine +was easily drawn aboard with a crane, and the Ohio steamed +down to the open sea, where it was blowing half a gale. But, +owing to the misjudgment of the ship's headway, one of the +wings of the machine when it struck the water after being +released from the crane, went under the water and was +snapped off. Lieut. Rodgers was convinced that this method +was too risky and that some other must be devised. + + + +CHAPTER XXVIII. + +GLOSSARY OF AERONAUTICAL TERMS. + +Aerodrome.--Literally a machine that runs in the air. +Aerofoil.--The advancing transverse section of an aeroplane. + +Aeroplane.--A flying machine of the glider pattern, +used in contra-distinction to a dirigible balloon. + +Aeronaut.--A person who travels in the air. + +Aerostat.--A machine sustaining weight in the air. A +balloon is an aerostat. + +Aerostatic.--Pertaining to suspension in the air; the +art of aerial navigation. + +Ailerons.--Small stabilizing planes attached to the main +planes to assist in preserving equilibrium. + +Angle of Incidence.--Angle formed by making comparison +with a perpendicular line or body. + +Angle of Inclination.--Angle at which a flying machine +rises. This angle, like that of incidence, is obtained +by comparison with an upright, or perpendicular line. + +Auxiliary Planes.--Minor plane surfaces, used in conjunction +with the main planes for stabilizing purposes. + +Biplane.--A flying-machine of the glider type with two +surface planes. + +Blade Twist.--The angle of twist or curvature on a +propeller blade. + +Cambered.--Curve or arch in plane, or wing from port +to starboard. + +Chassis.--The under framework of a flying machine; the +framework of the lower plane. + +Control.--System by which the rudders and stabilizing +planes are manipulated. + +Dihedral.--Having two sides and set at an angle, like +dihedral planes, or dihedral propeller blades. + +Dirigible.--Obedient to a rudder; something that may +be steered or directed. + +Helicopter.--Flying machine the lifting power of which +is furnished by vertical propellers. + +Lateral Curvature.--Parabolic form in a transverse direction. + +Lateral Equilibrium or Stability.--Maintenance of the +machine on an even keel transversely. If the lateral +equilibrium is perfect the extreme ends of the machine +will be on a dead level. + +Longitudinal Equilibrium or Stability.--Maintenance of +the machine on an even keel from front to rear. + +Monoplane.--Flying machine with one supporting, or +surface plane. + +Multiplane.--Flying machine with more than three surface +planes. + +Ornithopter.--Flying machine with movable bird-like +wings. + +Parabolic Curves.--Having the form of a parabola--a +conic section. + +Pitch of Propeller Blade.--See "Twist." + +Ribs.--The pieces over which the cloth covering is +stretched. + +Spread.--The distance from end to end of the main surface; +the transverse dimension. + +Stanchions.--Upright pieces connecting the upper and +lower frames. + +Struts.--The pieces which hold together longitudinally +the main frame beams. + +Superposed.--Placed one over another. + +Surface Area.--The amount of cloth-covered supporting +surface which furnishes the sustaining quality. + +Sustentation.--Suspension in the air. Power of sustentation; +the quality of sustaining a weight in the air. + +Triplane.--Flying machine with three surface planes. + +Thrust of Propeller.--Power with which the blades displace +the air. + +Width.--The distance from the front to the rear edge +of a flying machine. + +Wind Pressure.--The force exerted by the wind when +a body is moving against it. There is always more +or less wind pressure, even in a calm. + +Wing Tips.--The extreme ends of the main surface +planes. Sometimes these are movable parts of the +main planes, and sometimes separate auxiliary planes. + + + + + +End Project Gutenberg Etext of Flying Machine: Construction and Operation + diff --git a/old/flymc10.zip b/old/flymc10.zip Binary files differnew file mode 100644 index 0000000..9ae5fcb --- /dev/null +++ b/old/flymc10.zip |