,,the ,,boys' ,,book ,,of ,,model ,,aeroplanes ,illustration3 ,launching the ,airship4 ,,the ,,boys' ,,book ,,of ,,model ,,aeroplanes ,,how ,,to ,,build ,,and ,,fly ,,them3 ,,with ,,the ,,story ,,of ,,the ,,evolution ,,of ,,the ,,flying ,,machine ,,by ,,francis ,a4 ,,collins ,,illustrated ,,with ,,many ,,photographs ,,and ,,diagrams ,,by ,,the ,,author ,illustration ,,london ,,eveleigh ,,nash #aiab ,,to ,,arnold ,,miller ,,collins 7,aged ,ten7 ,,than ,,whom ,,no ,,collaborator ,,could ,,have ,,been ,,more ,,enthusiastic ,,contents ,,part ,i ,,models3 ,,how ,,to ,,build ,,and ,,fly ,,them ,,chapter ,,page ,i4 ,,the ,,new ,,sport ,,for ,,boys #c ,,ii4 ,,why ,,the ,,aeroplane ,,flies #ah ,,iii4 ,,how ,,to ,,build ,a 8,,glider0 #cj ,,iv4 ,,building ,,the ,,motor #ej ,v4 ,,fine ,,points ,,of ,,construction #fh ,,vi4 ,,simple ,,monoplane ,,models #hd ,,vii4 ,,elaborating ,,the ,,monoplane #ajb ,,viii4 ,,building ,a ,,biplane #aba ,,ix4 ,,combining ,,monoplane ,,and ,,biplane ,,forms #acg ,x4 ,,faults ,,and ,,how ,,to ,,mend ,,them #adc ,,part ,,ii ,,the ,,history ,,and ,,science ,,of ,,aviation ,i4 ,,the ,,first ,,flying ,,machines #afc ,,ii4 ,,developing ,,the ,,aeroplane #age ,,iii4 ,,the ,,wright ,,brothers' ,,own ,,story #aic ,,iv4 ,,aboard ,,the ,,wrights' ,,airship #bbd ,v4 ,,other ,,aeroplanes ,,appear #bch ,,vi4 ,,successful ,,monoplanes #bed ,,vii4 ,,aerial ,,warfare #bgb ,,viii4 ,,sports ,,of ,,the ,,air1 ,,aeroplanes #bic ,,list ,,of ,,illustrations ,,page ,launching the ,airship ,frontispiece ,a ,junior ,aroclub with its ,instructor in ,one of the ,new ,york ,public ,schools #g ,a ,young ,inventor in ,his ,workshop #ad ,boys ,comparing ,models #ad ,the ,first ,glider ,weighted at the ,front #bh ,dowel ,strips of ,different ,sizes #cc ,plate ,a--,diagrams of ,plan of ,aroplane on ,page #eh #ch ,a ,coil of ,cane or ,reed #db ,splitting a ,bamboo ,fish-,pole #dg ,plate ,b--,the ,propeller before ,cutting ,down #ea ,model ,constructed from ,diagram1 ,plate ,a #eh ,splitting the ,segar ,box ,cover to ,build the ,propeller #fc ,plate ,c--,the ,diagram of a ,monoplane #fe ,a ,model ,aroplane ,built from the ,drawing 7,plate ,c7 #ga ,detail of ,rudder and ,propeller of ,model ,built from ,drawing 7,plate ,c7 #gh ,plate ,i--,a ,clever ,folding ,model4 ,the ,wings ,are ,broader than ,need ,be #hh ,plate ,,ii--,a ,model ,aroplane ,worth ,imitating #ic ,plate ,,iii--,an ,ingenious ,french ,model ,made of ,umbrella ,wire #ajj ,plate ,,iv--,one of the ,simplest of ,aroplanes to ,construct #aje ,plate ,v--,too ,large for ,beginners but ,will ,make ,long ,flights #aab ,model ,shown in ,plate ,v ,ready for a ,flight #aag ,plate ,,vi--,a ,model with ,both ,good and ,bad ,features #abd ,plate ,,vii--,a ,good ,example of ,careful ,designing and ,workmanship #abi ,plate ,,viii--,an ,effective ,model with ,wooden ,wings #acf ,plate ,,ix--,an ,interesting ,experiment ,along ,new ,lines #aci ,plate ,x--,an ,excellent ,monoplane ,capable of ,long ,flights #aej ,detail of ,model ,shown in ,plate ,x #aec ,plate ,,xi--,well ,thought ,out ,monoplane #aeh ,plate ,,xii--,a ,good ,example of ,tilted ,planes #afe ,plate ,,xiii--,a ,serviceable ,form ,made of ,wire #agb ,plate ,,xiv--,the ,under ,body of the ,monoplane ,shown in ,plate ,,xiii #agi ,plate ,,xv--,a ,simple ,model which ,proves ,steady in ,flight #ahd ,plate ,,xvi--,the ,propeller and ,shaft of the ,model ,shown in ,plate ,,xv #ahi ,plate ,,xvii--,an ,ingenious ,model which ,fails to ,fly #aif ,plate ,,xviii--,a ,good ,model ,excepting ,that ,its ,vertical ,rudders ,are ,too ,large #bja ,plate ,,xix--,a ,simple ,cellular ,form #bjh ,plate ,,xx--,a ,cellular ,type with ,rudder and ,elevating ,plane #bac ,plate ,,xxi--,a ,complicated ,model ,capable of ,long ,flights #bbj ,plate ,,xxii--,an ,interesting ,form which ,flies ,backward or ,forward #bbe ,plate ,,xxiii--,a ,well ,built ,model ,badly ,proportioned #bcj ,plate ,,xxiv--,wright ,model ,ready for ,flight #bce ,plate ,,xxv--,another ,view of the ,wright ,model #bdf ,plate ,,xxvi--,an ,ingenious ,model which ,rises ,quickly #bea ,plate ,,xxvii--,an ,aroplane with ,paper ,wings #bee ,a ,very ,simple ,monoplane for ,beginners #bfb ,otto ,lilienthal about to ,take ,flight #bfg ,a ,machine for ,testing the ,lifting ,power of ,aroplanes #bgd ,maxim's ,first ,aroplane #bhj ,the ,machine on the ,rails1 as it ,appeared in #ahic #bhj ,first ,flight of the ,wright ,brothers' ,first ,motor ,machine #bhe ,three-quarter ,view of a ,flight at ,simms ,station1 ,november #af1 #aijd #bib ,front ,view of the ,flight of the ,wright ,aroplane1 ,october #d1 #aije #big ,,part ,i ,,models3 ,,how ,,to ,,build ,,and ,,fly ,,them ,,the ,,boys' ,,book ,,of ,,model ,,aeroplanes ,,chapter ,i ,,the ,,new ,,sport ,,for ,,boys ,in the boy's calendar nowadays the aroplane season comes in with sledding and runs all through skating1 marble1 top1 kite-flying1 and bicycle time4 ,the delights of all the old games seem to be found in this marvelous new toy4 ,the fun in throwing a top cannot compare with that of launching an aroplane1 while kite-flying is a very poor substitute for the actual conquest of the air4 ,to watch one of these fascinating little ships of the air1 which you have fashioned and built with your own hands1 actually rise from the earth and soar aloft with a swallow's swiftness1 is perhaps the greatest boy's sport in the world4 ,certainly no new game or toy has ever taken such hold of the boy's imagination1 and in so short a time enrolled such an army of enthusiasts4 ,throughout the country to-day upward of ten thousand boy aviators are struggling with the problem of the air-ship4 ,among these junior aronauts the record for height and that for distance in flying are matters of quite as lively interest as among the grown-ups4 ,the great contests of aviators here and abroad are watched with intelligent interest4 ,let a new form of aroplane1 a biplane or monoplane1 appear1 and it is quickly reproduced by scores of models and its virtues put to an actual test4 ,if a new wing or new plan for insuring stability is invented1 a new thought in the steering-device1 or some new application of power1 it is instantly the subject of earnest discussion among the junior aronauts the country over4 ,nor are junior aronauts merely imitators4 ,the mystery of the problems of the air1 the fascination of a new world of conquest1 make a strong appeal to the ,american temperament4 ,with thousands of bright boys working with might and main to build air-ships which will actually fly1 there is certain to be real progress4 ,thousands of different models have been designed and put to actual test4 ,this army of inventors1 ranging in age from twelve to eighteen years1 some of whom will be the aviators of the future1 cannot fail to do great service1 as time goes on1 in the actual conquest of the air4 ,within a few months this army of inventors has become organized into clubs1 and a regular program of tournaments has been arranged4 ,the junior aro clubs are found in connection with many schools1 both public and private2 they are made features of the ,young ,men's ,christian ,association amusements1 or they become identified with various neighborhoods4 ,tournaments are arranged between clubs of different cities or ,states1 while an international tournament is even planned between the ,united ,states and ,great ,britain4 ,the junior aro world has its prizes1 which are scarcely less coveted than the rewards for actual flight4 ,some fifty medals have been distributed this year among the members of the ,new ,york ,junior ,aro ,club4 ,many elaborate trophies will be contended for during #aiaj by the junior aronauts of the country4 ,a handsome silver cup of special design has been presented by ,mr4 ,a4 ,leo ,stevens1 and a second by ,mr4 ,sidney ,bowman1 while similar trophies are offered by ,commodore ,marshall1 ,o4 ,chanute1 and others4 ,the toy aroplane is not limited to any one season1 as one's sled1 kite1 or skates4 ,in the winter months the tests of flight may be carried out in any large room or hall4 ,there is even an advantage in holding such a tournament in a large school-room1 riding-academy1 or armory1 since there is no baffling wind to contend with4 ,already definite rules have been laid down for conducting these tests and for making official records of flights4 ,it is possible1 therefore1 to compare the records made in different cities or countries with one another4 ,illustration3 ,a ,junior ,aroclub with ,its ,instructor in ,one of the ,new ,york ,public ,schools4 ,the junior aro tournaments are likely to be the most thrilling experience in a boy's life4 ,the feats which the world has watched with such breathless interest at aviation meets at ,rheims1 ,pau1 or ,los ,angeles are reproduced in miniature in these boys' contests without loss of enthusiasm4 ,the weeks or months of preparation in scores of little workshops are now put to an actual test4 ,the model air-ship1 which has cost so many anxious and delightful hours in the building1 is to spread its wings with scores of similar air-craft4 ,the superiority of the monoplane or biplane forms is to be tested without fear or favor4 ,for the young inventors1 even for the mere layman in such matters1 the scene is extremely animated4 ,on every hand one sees the inventors tuning up their air-craft for the final test4 ,there are lively discussions in progress over the marvelous little toys4 ,the layman hears a new language spoken with perfect confidence about him4 ,the boys have already made the picturesque vocabulary of the world of aviation their own4 ,the discussion ranges over monoplanes and biplanes1 cellular types1 and flexed planes1 or of rigid and lateral braces4 ,to hear a crowd of these enthusiasts shout their comments as the air-ships fly about is in itself an education in advanced aronautics4 ,directly the floor is cleared1 the judges take their position1 and the junior sky-pilot toes the mark1 air-ship in hand4 8,one1 two1 three10 shouts the starter1 and with a whir the graceful air-craft is launched4 ,the flutter of the tiny propeller suggests the sudden rise of a covey of partridges4 ,the little craft1 at once so graceful and frail1 defies all the accepted laws of gravitation4 ,it darts ahead in long1 undulating curves as it floats over the invisible air-currents4 ,as in the aroplanes of larger size1 the length of the flight is dependent almost wholly on the motive power4 ,as the little engine slows down1 the craft wavers1 and then in a long curve1 for it can do nothing ungraceful1 it glides to rest1 skidding along the floor like a bird reluctant to leave the sky4 ,when the time comes for the races between the air-craft1 enthusiasm runs high4 ,naturally these contests are the most popular features of the tournament4 ,a line of inventors1 with their air-craft1 usually six at a time1 take their positions at the starting-line4 ,each air-craft has been tuned to its highest powers4 ,the labor of weeks1 the study of air-craft problems1 the elaboration of pet inventive schemes1 are represented in the shining model4 ,and the problem before the young inventors is most baffling4 ,there are few models to work from1 the science is still so young1 and the inventor may well feel himself something of a ,columbus in launching his frail craft upon this uncharted sea4 ,at the signal half a dozen propellers are instantly released1 a whirring as of innumerable light wings fills the air4 ,the curious flock of mechanical birds rises and falls1 dipping in long1 graceful curves as they struggle toward the goal4 ,some graceful little craft perfectly reproducing to the last detail the famous ,wright machine shoulders along beside a glistening monoplane which resembles a great hawk with wings outspread4 ,the next craft is perhaps a complicated arrangement of planes of no registered type1 while the craft made familiar by the photographs of the famous aviators are reproduced4 ,the thrill of an aroplane race is a sensation peculiarly its own4 ,it seems so astonishing that the graceful little craft should remain aloft at all1 that they are a never-failing delight to the eye4 ,the varying fortunes of the race1 the temporary lead gained by one craft1 to be lost the next moment to another1 which a second later itself falls behind1 and the final heat between the survivors in the race as they approach the goal1 are enough to drive the average boy crazy with delight4 ,illustration3 ,a ,young ,inventor in ,his ,workshop4 ,illustration3 ,boys ,comparing ,models4 ,the rules for these contests are rigidly observed4 ,each air-craft is sent aloft by its inventor or owner4 ,the start must be made from a mark1 and of course each aroplane must toe the mark4 ,there must be three judges for each event4 ,one stands at the starting-line and gives the word of command for the start of the race or flight1 as the case may be4 ,a second judge stands midway down the course1 and the third at or near the finishing-line4 ,each young aviator winds up his craft1 adjusts the power with his own hands1 and sets the rudder for the flight4 ,the miniature air-craft must act in flight exactly the same as the great working air-craft which carry men aloft4 ,a toy air-ship must make its flight in a horizontal position1 and if it turns over in flight1 even though it flies farther and faster than any other1 it is disqualified4 ,the craft must also fly in a reasonably straight line toward the goal1 and should it be deflected for any reason and go off at a tangent1 the flight1 no matter how successful otherwise1 will not be counted4 ,in case of a collision between air-craft1 the race is repeated4 ,the responsibility for adjusting the power1 arranging the steering-gear1 and giving direction to the flight at the start is entirely in the hands of the young engineer himself4 ,in measuring the length of the flights1 again1 the point at which the air-ship first touches the ground is fixed arbitrarily as the end4 ,often the little craft merely grazes the ground to rise and skid for many feet1 but in the official count this secondary flight is not considered4 ,first and last1 no one but the owner of the little craft is permitted to touch it4 ,the grace with which the ship lands is also taken into consideration in granting the prizes4 ,each boy is permitted three trials4 ,as in the regular aviation world1 these records rarely stand for more than a few days at a time4 ,these air-ships are driven by ropes of rubber bands which are turned on themselves until they are tightly knotted1 when in unwinding they serve to drive the propeller around some hundreds of times4 ,the rubber is so light that it adds little to the weight of the craft4 ,the motor is of course a makeshift and at best only serves to keep the propeller in motion for a fraction of a minute4 ,experiments have been made in driving the propeller with compressed air1 which is carried in an aluminium rod fastened beneath the planes4 ,but the force of thousands of youthful inventive geniuses is certain to bring forth some new motive power4 ,it is characteristic of the ,american boy that our young aviators should feel themselves disgraced to fly a model not of their own make4 ,as a result1 miniature craft of amazing ingenuity and workmanship are being turned out by the amateur aviators all over the country4 ,the materials employed1 such as rattan1 bamboo1 or light lath1 and the silk for covering the planes1 or the wires for bracing the frame1 cost but a few pennies4 ,toy aviation is one of the most democratic of sports4 ,,chapter ,,ii ,,why ,,the ,,aeroplane ,,flies ,the aviator must venture in his frail craft upon an unknown and uncharted sea4 ,the great problem is to ride the shifting air currents and keep the machine right side up4 ,although we cannot see the air currents1 we know that they are constantly ebbing and flowing1 piling themselves in great heaps1 or slipping away in giddy vortices4 ,there is much beautiful scenery1 high mountain peaks1 deep valleys1 and level plains formed by these ever shifting air currents through which the aviator must steer his course blindly as best he may4 ,a great bank of whirling clouds driven before the wind shows how rough and tumbling a sea he must navigate4 ,the air being a much thinner medium than water is1 of course1 far more unstable and baffling4 ,its supporting power is not only very small but constantly varies4 ,the flying machine which will navigate successfully in a perfectly quiet atmosphere may be unseaworthy1 or rather1 unairworthy1 when a wind springs up1 or the shifting of the wind may spoil all the air pilot's plans4 ,to add to his troubles1 the aviator must move among air currents which change and change again in a moment's time4 ,as we study the difficulties of air navigation we will appreciate1 more than ever1 the wonderful patience1 skill1 and daring of the successful aviators4 ,the action of the air currents had first to be carefully studied before flight became possible4 ,although the air is invisible we now know exactly how the air currents act upon the wings or planes4 ,when a plane surface1 such as the wing of an aroplane1 moves horizontally through the air1 the air is caught for a moment underneath it and is pressed down slightly and a moment later slips out again from under the other edges at the sides and back4 ,it is this air under pressure which yields a slight support4 ,it has been proven by many experiments that this supporting power varies with the shape of the plane or surface driven horizontally through the air4 ,a long narrow surface driven sideways gains much more support from the air than the same area in the form of a square or any other shape4 ,in other words1 a square surface ten feet square containing #ajj square feet will not travel as far as a surface twenty feet long and five feet wide4 ,the explanation is very simple4 ,as the square surface moves along1 the air is momentarily compressed under the front edge1 but instantly slips off at the back and sides4 ,as the broad surface of the rectangular plane cuts the air1 however1 few of the air currents can escape at the sides while the most of them are crowded together and held in place until they slip off at the back4 ,the supporting power of the plane is therefore in direct proportion to the length of the front or1 as it is called1 the entering edge of the plane4 ,here we find one of the secrets of the flight of birds4 ,the spread between the tips of their outstretched wings is much greater than the width of the wings themselves4 ,it also explains why the ,wright model1 for instance1 should be so oddly shaped and should move sideways like a crab4 ,if you study the models of the successful monoplanes with this in mind they have a new meaning4 ,the law of the proportion of the entering edge is very important in designing an aroplane4 ,it is so important for the air to be confined as long as possible beneath the gliding plane that many devices have been tried to hold it4 ,some planes are built with a slight edge running around the sides and back1 on the under surface1 to hem in the air4 ,some of the biplanes are built with closed sides1 the cellular form they are called1 to keep the air from slipping away4 ,the box kite is constructed with this in view4 ,the builder of model aroplanes will find1 however1 that the slight edge formed by turning the cloth over the frame of the plane is sufficient to hold the air4 ,the flight of a kite1 by the way1 appears a very simple matter once this law is understood4 ,the air currents strike the kite at an angle and are deflected or carrom off at exactly the same angle4 ,a line drawn through the middle of this angle1 exactly bisecting it1 will give you the direction of the force exerted by the wind4 ,meanwhile the kite string holds the plane rigidly in position4 ,as the kite darts from side to side it is merely obeying this law and adjusting itself so that its surface will stand at right angles to this thrust of the wind4 ,an aroplane is simply a kite which makes its own wind or air currents4 ,the kite is1 of course1 balanced against the wind currents and kept more or less stable by its cord1 but an aroplane must balance itself4 ,the secret of insuring stability was discovered only after years of experience with gliders in actual flights4 ,the stability of the aroplane depends upon the proper adjustment of the pressure of the air on the machine4 ,there is1 of course1 a center of pressure1 just as there is a center of gravity in every aroplane of whatever form or size4 ,it may be laid down as a general rule that a plane traveling horizontally in a quiet atmosphere is kept horizontal and stable by making the centers of pressure and gravity coincide4 ,the air currents1 as we pointed out1 are never entirely at rest but are constantly tilting the plane about4 ,hold a sheet of stiff paper horizontally and let it fall4 ,it will flutter to the ground or perhaps be twirled away1 indicating the presence of a number of unexpected air currents4 ,the aroplane which would remain stable in a perfectly quiet atmosphere must overcome all these twists and turns4 ,the problem of stability has not yet of course been solved4 ,having reached this stage in the evolution of the aroplane the aviator next began to experiment by bending his wings or planes and throwing out lateral or stability planes to help him keep his balance4 ,it was now found that a very little tilting of the planes upward or downward would serve to right the machine when it leaned over4 ,the secret1 like so many others1 was gained by watching the flights of birds4 ,you have perhaps seen a great albatross or sea gull soar without the slightest effort and apparently without motion4 ,look more closely and you will see that the tips of the broad wings move slightly from time to time1 while the main body of the wings remains rigid1 which is the great secret of stability in flight4 ,the ends of the planes were next made flexible1 very slightly so1 and arranged so that they might be moved up and down or flexed at will4 ,the flights made with this adjustment were at once brought under control4 ,new planes were added before and behind1 and it was found that the machine could be kept from darting up and down just as well as tilting over at the ends4 ,the aroplane was now ready for the installation of the motor4 ,the best curve for the wing of an aroplane is an irregular curve drawn above the horizontal line4 ,it is not a perfect arc of a circle but reaches its greatest height about one third back of the front edge1 with the rest of the line slightly flattened4 ,it is much the same line as is formed by some waves just before they break4 ,the plane thus shaped is driven with the blunt or entering edge forward or against the wind4 ,in building the large aroplanes this curve is worked out with great accuracy1 but the builder of model airships may carry the line in his eye4 ,as the air strikes the entering edge of this surface it is driven underneath and held there for a moment before it can escape from beneath this hollow4 ,the support of the air is therefore greater than in the case of a flat plane1 or in fact1 any other form4 ,the air which passes over the top of the entering edge1 meanwhile1 glides or slips off at a slight upward angle1 thus forming a partial vacuum over the greater part of the upper surface4 ,this vacuum1 in turn1 tends to pull the plane slightly upward thus acting in the same direction as the air which is compressed beneath it4 ,the planes thus constructed are1 besides1 much more easily controlled than those of any other shape4 ,when the entering edge of this plane is raised the pressure of the air beneath is increased and the pull of the partial vacuum combines with it to make it rise4 ,the difficult problem of getting the aroplane aloft was largely solved by this curve4 ,once aloft1 such an airship answers her helm much better than any other form4 ,this curve is accountable for many of the movements of aroplanes which seem so mysterious to the mere layman4 ,when an aroplane turns1 its outer end rises1 and the more rapid is its flight the greater is this tilt4 ,it must be remembered that the end is moving more rapidly and the increased speed causes the plane to lift4 ,many photographs of aroplanes show them balanced at precarious angles while making a turn4 ,if the plane is tilted too high the air currents slip out from beneath1 no vacuum is developed above1 and it quickly loses speed4 ,on the other hand1 if it be inclined downward it soon loses the supporting power of the air and plunges down4 ,illustration3 ,the ,first ,glider ,weighted at the ,front4 ,at every stage of this development the aviators are indebted to the birds for information4 ,the successful aroplanes have great width compared to their depth1 they gain stability by flexing the tips of the wings1 and their planes are arched upward and forward exactly as are the wings of a bird4 ,the aviator arranges his center of gravity after the same general model1 below the planes and well forward4 ,he places his engine forward1 just as the bird has its strongest muscles in the chest1 and he builds his frame of hollow tubes like the bones of a bird4 ,,chapter ,,iii ,,how ,,to ,,build ,a 8,,glider0 ,the simplest form of heavier-than-air machine is the stiff card or letter which you may spin across the room4 ,if you give it just the right twirl it will glide on a level for many feet4 ,there are many ways besides of folding a sheet of stiff paper which will convert it into a surprisingly clever little airship4 ,with a little practice these gliders may be made to fly ten or twenty times their own length1 which would be a very creditable flight for the best aroplane models4 ,there is no better way to begin the construction of a model aroplane than by study and experiment with these paper ships4 ,the most famous aronauts of the day1 the ,wright brothers1 ,curtiss1 ,herring1 and many others1 have spent years working with gliders before attempting to build or fly an aroplane4 ,it is in this way that they discovered what form of wing would support the greatest weight1 whether the passenger should stand up or lie down1 how to place the propeller and the rudder1 and hundreds of other details which have made possible the actual conquests of the air4 ,following in their footsteps1 or rather their flights1 the amateur aronaut should first build and fly only gliders or aroplanes without means of self-propulsion4 ,the simplest form of glider may be made by cutting a broad oval from a sheet of stiff letter-paper and creasing it down the middle4 ,the experiment may be made more interesting1 however1 by cutting out the plane like the outstretched wings of a bird1 as suggested in the accompanying illustration4 ,try as you may1 this sheet will not fly4 ,now add a trifling weight to the front of the plane4 ,this may be done by fastening one or more paper clips to the edge1 pasting a match or a toothpick1 or by dropping a little tallow or sealing-wax4 ,at first you will underestimate the weight your little airship will carry4 ,add more weight in the same way1 and test its gliding powers until the little airship will glide gracefully across the floor4 ,keep the length of these models under six inches4 ,if you increase it beyond this1 the model loses steadiness and flutters about ineffectively4 ,an interesting model may be made by folding a sheet of stiff paper in an arrow-like form4 ,the idea is to form a series of planes which will support the weight of the tiny craft and1 at the same time1 enable it to fly or dart in a straight line4 ,it will be found that the vertical surfaces lend stability and keep the ship moving in a straight line4 ,you will soon learn1 in this way1 more of the principles of aroplane construction than mere reading from books can teach you4 ,be careful1 meanwhile1 to remember just how you have launched the various forms of models1 whether you have thrown them with an upward or downward motion1 and how hard a push you have given them4 ,the skill you acquire in this way will be valuable later on when you come to launch your regular model aroplane4 ,illustration3 ,dowel ,strips of ,different ,sizes4 ,we are now ready to begin the construction of the frames of aroplane models4 ,the first model will be merely a glider4 ,the frame and wings or planes of an aroplane are built much the same as a kite4 ,the idea in all such work is to combine the greatest possible strength or stability with extreme lightness4 ,remember1 however1 that the aroplane during its flights is racked and shaken by its motor1 and is likely to land with a bump4 ,the materials used must be stronger than in the case of an ordinary kite1 the joints more securely formed1 and the entire structure braced in every possible way4 ,the best materials for constructing these gliders or aroplanes are very cheap and easily obtained4 ,at almost any hardware-store you will find a variety of 8dowel-sticks10 which seem especially made for this work4 ,they are smooth1 round sticks a yard in length and of a variety of diameter4 ,the sticks three sixteenths of an inch in diameter will be found most serviceable1 while the larger sticks are just the thing for the backbones of your aroplane4 ,these sticks will not split at the ends and may be readily worked4 ,they cost one cent apiece4 ,some boys find that the reed or cane suits their purpose better than the dowel-sticks1 since it is more flexible and a trifle lighter4 ,the cane is easy to work when you wish to build planes with curved lines4 ,it can be readily shaped to any desired form by first wetting it and allowing it to dry after working4 ,care must be taken in using it1 since the ends are likely to split4 ,bundles of this cane may be bought at most hardware-stores or in department-stores4 ,enough material for constructing a model may be bought for a few cents4 ,the lightest of all available materials is bamboo4 ,it is difficult to procure1 however1 and requires more working up than the others4 ,the best plan is to buy a stick of bamboo1 a dry piece1 and split it into strips of the desired length and thickness4 ,the grain is so straight that there is practically no waste material as in ordinary wood4 ,the strips may be readily planed or sandpapered4 ,the wood is extremely light and strong enough for all practical purposes of the model aroplane builder4 ,an old bamboo fishing-pole may answer your purpose4 ,the first gliders constructed should be of the monoplane form1 that is1 with a single surface4 ,the biplane or multiplane models will come later4 ,meanwhile1 one is not losing time in working only on these simple models1 for the experience is valuable and nothing is lost1 since when the frame is properly constructed the motor and propeller may be added4 ,the work throughout is extremely simple1 and there are no problems of which the average ingenious ,american boy need be afraid4 ,illustration3 ,,diagram ,,for ,,plan ,,of ,,the ,a,,roplane ,,on ,,page #eh4 ,illustration3 ,,diagram--,,shown ,,in ,,perspective4 ,,plate ,a4 ,to construct the model shown in ,plate ,a first make two frames of dowel-sticks1 bamboo1 or reed1 or1 if these be lacking1 of light lath1 the smaller frame #h by #ai and the larger one #aj by #cf inches4 ,care must be taken to have the sides of the rectangle exactly the same length and the joints closely and neatly finished4 ,some boys prefer to lay one stick over another1 then wrap the joint tightly with thin but strong linen thread1 and over this brush a coat of thin glue1 without using any brads or nails4 ,in kite-building1 to be sure1 it would be enough to lay the strips over one another and fasten roughly with a tack4 ,nor did the lengths of the stick1 when covered with paper1 make much if any difference4 ,the aroplane1 it must be remembered1 travels edgewise1 and1 having no guiding string1 is at the mercy of every gust of wind4 ,if the frames are carelessly proportioned it will not travel true1 but is likely to be deflected4 ,imagine a boat whose sides are not exactly uniform trying to travel in a straight line4 ,it would be lopsided1 and would roll and pitch under the most favorable conditions4 ,now an aroplane1 since it travels in so thin a medium as air1 is far more sensitive than a boat1 and it becomes lopsided if its proportions be in the least inaccurate4 ,only the greatest care in construction will produce an air craft which will fly true and straight4 ,it makes little or no difference in a kite if the ends project a little and the joints be carelessly made4 ,not only must your aroplane be perfectly proportioned1 but it must be finished like a piece of fine furniture4 ,the question of friction is a very important one in the heavier-than-air machine4 ,you cannot be too careful to round off every corner and smooth every exposed surface4 ,if you have opportunity to see a regular aroplane1 a ,wright or ,curtiss model1 you will find that every part of the machine has been sandpapered and varnished with the greatest care4 ,this is not done for the sake of appearances1 but because it has been found that the wind striking against the rough piece of wood meets an appreciable amount of resistance1 whereas it slips past a polished surface with little or no friction4 ,your aroplane should be finished like a violin4 ,illustration3 ,a ,coil of ,cane or ,reed4 ,in building these planes be careful to compare the lengths of the corresponding sides throughout4 ,if you prefer to use brads for fastening the joints do so4 ,the dowel-stick and bamboo will take the brads with little danger of splitting4 ,when thoroughly dry1 cut away the glue which has squeezed out1 round off the ends1 and sandpaper with fine sand or emery-paper4 ,if you use brads it will not be necessary to place the joints in a vise while drying4 ,should your strips split1 bore the holes with a fine awl4 ,some boys after drilling the holes merely tie and glue the sticks together1 using no nails whatever4 ,now cut three dowel-strips #cd inches long and slightly sharpen their ends1 so that when brought together they will form a prism whose base is about one fourth their length4 ,next bend a strong piece of wire into a hook--a hair-pin will answer for small models--and fasten it in the apex of the prism1 with the hook inside4 ,the projecting end of wire should then be bent over1 and the three dowel-sticks glued and tied tightly together4 ,at the open end of the prism next fasten two strips from end to end1 leaving the third side of the triangle open4 ,now fasten your two planes on the open side of the prism1 slightly mortising the sticks and gluing and nailing them securely in position4 ,to further strengthen the prism1 join the three sides at the middle with three sticks1 forming a complete triangle4 ,the prism thus braced will be found as strong as a heavy central stick1 besides being much lighter and providing an excellent base for the propeller4 ,a strong stick about half an inch square should be tied and glued across the middle of the triangle at the base of the prism to support the motor4 ,the frame once complete1 sandpapered and varnished1 it is ready to be covered4 ,at first this may be done with some smooth paper4 ,almost any thin material1 muslin or linen1 will answer for the purpose1 although white silk makes the most finished-looking model4 ,such scraps as may be found in the family piece-bag will answer every purpose4 ,in sewing the cloth over the frame the advice of some big sister1 aunt1 or the mother may well be taken4 ,the idea is to fasten the cloth smoothly and neatly over the frame1 keeping the surface free from creases or wrinkles of any kind4 ,boys are likely to be awkward with the needle4 ,the cloth may also be glued over the frames4 ,when complete cover the planes with a thin solution of paraffin dissolved in benzine4 ,in attaching the planes or wings to the central axis of the model1 the larger stick or backbone may be mortised neatly1 so that the sides of the frame will be sunk in flush with the upper surface4 ,a fairly good glider may be made1 however1 by merely nailing down the frames against this backbone4 ,the distance between the two planes is a complicated problem1 but the beginner had better at first imitate the model shown in the accompanying illustration4 ,if the two supporting planes be too far apart or too near together1 the glider will fall4 ,the amateur must experiment by changing their position on the central axis until he hits the right proportion4 ,he will be able later to carry this proportion in his eye1 and the experience will prove invaluable4 ,until you have hit upon the proper position1 fasten them to the backbone with rubber bands4 ,these permit you to slide the planes back and forth without the trouble of nailing4 ,aroplanes1 unlike kites1 fly best in a perfectly quiet atmosphere4 ,if you make your trial flights out of doors1 select a quiet day4 ,a room1 a barn1 or any large interior will be found better4 ,in launching your glider1 hold it from beneath1 so that it balances1 and throw it forward with a swift1 steady movement of the arm4 ,a little practice will make you very expert4 ,illustration3 ,splitting a ,bamboo ,fish-,pole4 ,you will now find yourself fitted to reproduce any of the simpler forms of monoplane models1 several of which are here illustrated4 ,an interesting model is made by attaching ,u-shaped wings to a central axis4 ,in making these curved planes the reed will be found useful4 ,other effective gliders are made with triangular wings fixed at a variety of angles4 ,remember that the model must be absolutely symmetrical4 ,in attaching the frames to the central axis1 always make the joints as smooth and rigid as possible4 ,the weighting of the glider will be found to be a very important detail4 ,as a rule the gliders require a considerable weight at the front4 ,the exact position of the weight can only be determined by experiment4 ,the simplest way is to wire a nail or a piece of metal to the edge of the frame4 ,if your glider does not balance perfectly1 which is likely to be the case1 this fault can be largely remedied by weighting it4 ,the tendency of the glider is likely to be upward1 and the weight serves to keep it on an even keel4 ,when your model glides steadily through the air1 without rolling or pitching1 you have constructed a well-balanced frame4 ,it will then be time to take up the problem of propulsion4 ,,chapter ,,iv ,,building ,,the ,,motor ,a well-constructed glider alone makes a fascinating toy1 but once the motor has been installed it seems almost alive4 ,your little craft will now be ready for new conquests4 ,it will imitate the flights of the famous aviators1 contending with the same problems1 perhaps meeting similar accidents4 ,the motor is the most interesting1 as it is the most important1 detail of the aroplane4 ,although it is possible to buy the propellers for the motor1 it is advisable that every boy should work out this problem for himself4 ,an effective motor is easy to build1 and costs practically nothing4 ,the length of your propeller-blades should be equal to about one third the width of your largest plane4 ,for this you will need six strips of some light wood1 such as pine or ash1 although a cigar-box wood1 if the grain be straight1 will answer4 ,cut the strips to measure about half an inch in width and one eighth of an inch thick4 7,see ,plate ,b47 ,illustration3 ,,the ,,propeller ,,before ,,cutting ,,down4 ,,plate ,b4 ,the strips should be covered with a thin glue and laid one on top of another1 and a very thin nail be carefully driven through the little pile at the exact center between the two ends4 ,while the glue is still soft1 turn the sticks on the axis formed by the nail1 so that they make a double fan1 spacing the outer edges about one quarter of an inch apart4 ,be certain that the fan is regular1 and then give the nail a final rap to tighten its hold and keep all the glued surfaces together1 and set away to dry4 ,if you can prop up the ends it will be better to put a flat-iron or other weight on each end to make the strips glue together tighter4 ,the thrust or propelling power depends as much upon the curves of the propeller as upon the force with which the motor is driven4 ,if the propeller be too flat1 it will not take hold of the air1 while if the pitch or angle of the curve be too sharp1 it will simply bore holes in the air and create a vacuum which is useless4 ,the pitch should be about one in twelve2 that is1 if the propeller-blade be twelve inches long1 the curve should be one inch high4 ,when the glue is thoroughly dry and hard the projecting step-like edges may be cut away4 ,a flat chisel or an ordinary pen-knife will do the work4 ,be careful to keep the ends uniform1 since much depends upon the balance4 ,cut away the wood until the blades are one eighth of an inch or less in thickness1 and round off the corners4 ,the propeller should then be sandpapered perfectly smooth and varnished4 ,you will be delighted to find how professional and shipshape the finished propeller will be4 ,now carefully remove the nail fastening the pieces1 and you will find1 of course1 that it marks the exact center and forms a perfect axis4 ,should you need to enlarge this hole1 do not attempt to bore it1 since this may split the wood1 but burn it out1 using a nail heated over a gas-flame4 ,now insert a stiff wire in this hole--a hat-pin will answer--and fasten it by clenching it at the back tight to the propeller1 and fill up the hole with glue4 ,the photographs of the propellers of various models will give you an excellent idea of the proper curve4 ,aviators differ as to the proper position for the propellers in toy aroplanes4 ,here is a problem you must work out for yourself4 ,some believe that the propeller placed in front of the planes gets a firmer grip on the air1 since when the propeller is at the stern the planes make many disturbing currents1 just as a steamship churns the water in its wake4 ,others argue that by placing this propelling force at the rear of the planes the craft is made more steady4 ,at any rate1 excellent flights may be made with either arrangement4 ,in connecting up your propeller with the motor it is very important that the shaft should turn freely and that the bearings offer the least possible resistance4 ,if you have built your aroplane from the drawing 7see ,plate ,a71 now drill a hole exactly in the center of the stick which crosses the triangle at the rear of the frame4 ,this hole will come on a line with the apex of the prism1 or exactly in the center of the triangle4 ,when the turning of the motor pulls the ends of the frame together1 the strain will therefore be exactly distributed among the three sides or braces4 ,the propeller must be kept clear of the frame and must never touch or scrape against it4 ,first a thin strip of metal1 drilled to take the axle or hat-pin1 should be nailed over the hole in the crosspiece4 ,a sheet of aluminium such as is used for name-plates is just the thing4 ,now on the propeller-wire or axis string a smooth1 symmetrical glass bead1 and pass the axle through the metal strip and the crosspiece4 ,this will give you an excellent substitute for ball-bearings4 ,the end of the wire should then be turned into a hook well inside the frame4 ,the propeller should be mounted so carefully that it will turn freely without friction and without wabbling from side to side4 ,the simplest and most effective motor is formed by connecting the two hooks with many turns of a long1 thin strand of rubber1 which can be bought by the yard or pound4 ,the thinner strands of rubber will exert more force than the heavy bands1 and red rubber is more durable than any other4 ,the bands should be looped loosely between the two hooks1 just as you would wind a skein of zephyr--over the hook on the propeller-8shaft10 then around the hook at the other end1 then down over the propeller-shaft hook1 and so on4 ,if the hooks be three feet apart the combined strands should form a band one inch or more in diameter4 ,if you cannot buy the rubber in this form1 a number of two-inch rubber bands1 such as you buy by the box at the stationer's1 may be lopped chain fashion together to form a continuous rope from hook to hook4 ,to store up energy for the flight1 simply turn your propeller round and round until the rope of rubber bands is tightly knotted4 ,you can readily tell when it is sufficiently wound and the danger-point is reached1 which comes when the pull of the rubber grows too strong for your frame4 ,the average motor should be turned about one hundred and fifty times4 ,when the propeller is released the rubber bands in unwinding will give you back almost exactly the same number of revolutions1 less perhaps one or two1 which represents the loss through friction4 ,illustration3 ,model ,constructed from ,diagram1 ,plate ,a4 ,if the propeller simply buzzes around1 coming to rest in a few seconds1 without raising your aroplane1 it is probably too small for the weight of the aroplane4 ,when fully wound up the propeller should run for about ten seconds4 ,on the other hand1 if the propeller be too large1 it will quickly twist the aroplane out of its course and drive it to earth4 ,it is well to try out your motor thoroughly to make sure of its running smoothly before attempting any actual flights4 ,do not yield to the temptation of trying your wings1 however1 until the skids have been attached4 ,most of the regular full-size aroplanes run on ordinary bicycle wheels1 although the ,wrights use runners like a sleigh4 ,these skids or runners enable the machine to run along the ground with the least possible friction and greatly assist in rising4 ,in the models of aroplanes the skids serve a double purpose in protecting the machine when it alights4 ,a serviceable skid may be made by building a triangle of thin strips and attaching it to the frame with the broad side downward1 as shown in the accompanying drawing4 ,skids made of reed curving down from the main body of the aroplane will also serve to take up the shock4 ,there are many ways of constructing these skids1 and a study of the models here illustrated will give many suggestions4 ,if you intend to have your aroplane start from the ground1 the front skids should be somewhat longer than those in the rear to give it the proper lift4 ,the friction of the skids is greatly reduced by mounting them on wheels4 ,small metal wheels may be borrowed from toy automobiles1 or small disks of wood or cork will answer for the purpose4 ,a very simple axis may be formed by running a long hat-pin through the uprights of the skids4 ,the photographs of the best models will be found full of suggestions4 ,you will need at least three skids to form a tripod for your aroplane4 ,it makes little difference if you use one leg in front1 or two4 ,it is very important that the frame should be properly braced to withstand the strain brought upon it4 ,in the glider this bracing is less important1 but the action of the motor changes the situation4 ,the rapid movement of the propellers wracks the entire frame1 and the impact on landing is naturally greater when the weight is increased4 ,a thin copper wire1 ,no4 #cb1 #cd1 or #cf1 should be used1 which will be found strong and flexible1 while adding little to the weight4 ,after constructing your aroplane go over it carefully and cut away the wood wherever it may be lightened1 and then strengthen it by bracing4 ,wherever a joint may be strengthened or a strut or a plane be made more rigid by bracing1 do not spare the wire4 ,the accompanying drawing1 with the photographs of models1 will indicate how these braces may best be applied4 ,to begin with1 braces should be run1 wherever possible1 from the corners of the planes to the central frame and the skids4 ,in the monoplane forms you will find it worth while to add posts or perpendiculars to the upper side of the frame and run wire braces diagonally to the ends of the planes4 ,the extreme ends of the planes should also be connected4 ,no matter how carefully you have constructed your aroplane1 you will find the planes have a tendency to sag and become wrinkled4 ,these braces give you the opportunity to pull them taut and hold them in this position4 ,this is commonly called 8tuning up0 the aroplane4 ,it will be found convenient to fasten small rings to the ends of the braces whenever they may be slipped over the ends of the frame to save the trouble of winding4 ,the more perfectly your aroplane is tuned up1 the greater will be its speed and distance qualities4 ,illustration3 ,splitting the ,cigar ,box ,cover to ,build the ,propeller4 ,an excellent monoplane for the beginner is shown in drawing4 7,plate ,c47 ,it is very simple and easily adjusted1 and when well tuned up will fly upward of two hundred feet4 ,the two planes are built separately in the proportion indicated4 ,the frame consists of a central stick supported by triangular skids4 ,an ordinary hat-pin run through the supports near the ground serves as an axle for wooden disks or wheels4 ,the front skids are made somewhat higher to give the front planes the proper angle of elevation4 ,illustration3 ,,the ,,diagram ,,of ,a ,,monoplane4 ,planes measure #bj inches by #h inches4 ,the motor base is #cf inches in length4 ,,plate ,c4 ,the bracing of the planes is simple but effective1 and should be copied carefully1 particularly the double bracing in the rear1 using ordinary wire for the purpose4 ,a double support is used for the axle of the propeller1 an excellent idea1 which keeps the shaft rigidly in place4 ,it is formed by fastening two blocks drilled to hold the axle to the bottom of the main frame4 ,the planes are held taut by wires running from the corners to a post at the middle of the plane4 ,the front plane is hinged at its rear edge1 and may be tilted by pulling back a piece of whalebone fastened at its center1 which is tacked to the top of the frame4 ,the rudder turns on a triangular frame attached to the top of the rear plane4 ,a string passes through the rear end of the rudder to the rear edge of the plane1 forming a triangle1 which makes it possible to adjust the rudder-plane and fix it rigidly in position4 ,after you have built one or two models you will find yourself confronted by a bewildering number of schemes for constructing new forms4 ,it will be found a very simple matter to use stiff wire for many parts of your model instead of wood or reed4 ,in building rounded planes the wire will be a convenience4 ,the wire may be attached to the wooden frame by embedding it in the wood and binding it fast4 ,and1 by the way1 you can get a surprising effect by painting your wooden frame with silver paint1 as the ,wrights do4 ,to all appearance you will have an aluminium frame4 ,an aroplane to be considered shipshape must be even more perfect in every detail than the finest racing yacht4 ,go over your model1 scrutinize every detail2 if after taking every precaution1 your planes do not fit like the sails of a racing yacht1 cover them with a thin solution of paraffin4 ,on hardening1 this will hold the material perfectly smooth1 so that the planes will offer a perfect lifting surface4 ,the amateur aronaut must be prepared for disappointments4 ,an aroplane is one of the crankiest crafts in the world to manage4 ,it may twist and turn1 plunge in and out1 up and down1 apparently without the least excuse4 ,there is always1 however1 a good reason somewhere for its behavior4 ,as you learn its ways1 which1 after all1 are very simple1 the flights will be longer1 swiftier1 and steadier4 ,there is no toy in the world which so quickly repays one for patience and perseverance4 ,,chapter ,v ,,fine ,,points ,,of ,,construction ,a great many experiments have been made to find whether the flat or curved wings give the best support1 and how sharply the curve should be drawn4 ,the wings of birds are curved slightly upward1 and in the end1 after all the experiments1 it has been found that this curve is just the right one4 ,all forms of aroplanes will fly more swiftly and steadily if the planes be slightly bowed or flexed4 ,after you have built your aroplane with flat wings it will repay you to replace them with flexed planes1 and you will find that the experience in building models will make this construction very simple4 ,the lighter and more flexible materials1 such as bamboo or cane1 are best for the curved planes4 ,after you have decided upon the dimensions of the wings cut the pieces for the ends slightly longer than the width of your planes4 ,these pieces may then be bent by steaming them over a kettle of boiling water and bending to the desired curve4 ,when dry they will hold their shape remarkably well4 ,another plan is to use a flexible strip and pull the ends together by a strong thread or wire until the wood is bowed to just the right curve4 ,a corset steel or whalebone may readily be curved in the same way4 ,it is a common mistake to curve the plane too sharply1 when the resistance offered to the air will be greater than that with the flat plane4 ,a plane two or three feet in width cannot be held in shape merely by curving the end pieces4 ,a series of ribs must be added at equal distances1 each having1 of course1 exactly the same upward curve4 ,the ribs may be fastened to the sides of the planes with small brads or simply with glue or wire4 ,the covering should then be drawn down4 ,a very smooth covering may be made of rice-paper4 ,cut the sheets the proper size and lay them for a few minutes between moistened cloths4 ,now stretch the paper carefully over the frame and glue in position4 ,when dry the paper will contract and leave a smooth1 taut surface like the head of a drum4 ,much depends upon the curve of the plane4 ,a wing whose curve is not a perfect arc of a circle1 but which is rounded just back of the front edge and flattened at the rear1 will be found to offer the least resistance to the air4 ,the best plan is to study the curves in the aroplanes or models and imitate them4 ,different models require different planes4 ,it is a problem which each young aronaut must work out for himself4 ,illustration3 ,a ,model ,aroplane ,built from the ,drawing 7,plate ,c1 ,chap4 ,,iv74 ,the question of rudders or guiding planes is very important4 ,it is too much to expect of even the best model that it will fly in an unswerving line4 ,any simple vertical plane which may be turned from side to side and held in position will act as a rudder4 ,there is great difference of opinion as to the proper size and position of these guiding surfaces4 ,it is argued by some aviators that the rudder should be placed above the plane1 where the air is undisturbed1 while others believe that the partial vacuum created above the wings in flight makes the propeller ineffective4 ,still others argue that a rudder placed back of the planes affords a leverage1 and is therefore more effective4 ,try a rudder in each position4 ,it is impossible to lay down a law for all models4 ,the larger models should be equipped with twin propellers4 ,in building these the greatest care should be taken to have them exactly the same size1 weight1 and pitch4 ,twin propellers should1 as a rule1 be placed at the front of the machine1 that is1 they should pull and not push the planes4 ,if by any accident the motor of one should fail1 the second propeller will continue to keep the aroplane afloat and break its fall on descending4 ,with the propellers at the stern of the little airship1 the failure of one would cause the plane to pitch downward1 and the remaining propeller would drive it down to possible disaster4 ,in winding up the two motors1 care should be taken to give both the same number of turns4 ,the aroplane may be launched by holding a propeller in either hand and releasing simultaneously4 ,the double motor insures a steadier as well as a longer flight4 ,always turn the propellers in opposite directions4 ,in flying they must spin around either toward each other or away from each other4 ,if they turn the same way they will give the model a torque which no rudder could possibly overcome4 ,the efficiency of your motor depends more upon its length than its diameter4 ,in constructing the motor-base1 especially for the larger models1 arrange to have the strands of rubber bands extend the entire length of your aroplane1 and if necessary1 project well forward of the front plane4 ,such a motor in unwinding will exert a more sustained force4 ,the shorter strands of greater diameter will unwind much more quickly and give very short flights4 ,with a little experience you will soon learn to gauge your motor to the needs of your air-ship4 ,it is1 of course1 absolutely necessary that the force exerted by the motor should be sufficient to keep your aroplane in rapid motion1 but it is easy to make it too powerful4 ,if it were possible to attach a 8governor0 to your motor1 this would not matter so much4 ,but since this is practically out of the question1 the motor itself must be very nicely proportioned to the demand made upon it4 ,you will soon be able to judge between the steady whir of a good motor1 and the buzz of a propeller which races4 ,there is a distinct note for each4 ,the motor is1 at present1 the great problem of the model aroplane4 ,the rubber bands are1 at best1 only a make-shift4 ,it is practically out of the question to get a flight of more than fifteen seconds in this way1 so that the distance is limited to a little more than two hundred feet4 ,it is doubtless only a question of time before a much more efficient form of motor will be invented4 ,very probably1 some amateur aviator will be the first to apply a new means of propulsion1 which would be an important achievement indeed4 ,the simplest form of motor after the rubber bands would seem to be some form of metal spring which could be wound up4 ,long before the days of automobiles1 as we now know them1 wagons were built with motors of springs1 and some surprising runs were obtained4 ,the spring lends itself to many forms of construction1 and is not expensive4 ,it will be necessary to control its action in some way1 however1 to prevent it from racing and running down in almost no time1 like the too heavy rubber motors4 ,it might be found interesting to experiment with the spring to be found in the ordinary roller-shade4 ,the weight of these springs is not too great to be carried by a good aroplane model1 which1 of course1 is a great factor in their favor4 ,illustration3 ,detail of ,rudder and ,propeller of ,model ,built from ,drawing 7,plate ,c74 ,a number of experiments have been made in ,france to equip aroplane models with compressed-air motors4 ,the compressed air is carried in a hollow tube in much the same position as the rubber bands4 ,many believe that the motor problem1 for the toy aroplane will be solved in this way4 ,a number of interesting models have also been equipped with clock-work motors4 ,a small movement1 such as may be borrowed from some mechanical toys1 will run for a minute or more4 ,what glorious flights would be possible if our models could be kept aloft--say five times as long as at present4 ,when you feel that you thoroughly understand your model1 borrow the clock work from some old toy and make the experiment4 ,it is possible to buy motors for model aroplanes4 ,the smallest of these develops one half horsepower1 weighs seven pounds and will run for fifteen minutes4 ,the best covering for the wings still remains largely an open question4 ,although your model will make successful flights with almost any kind of covering1 you will find that its stability will be increased and the flight lengthened by a little attention to this detail4 ,according to the ,wright ,brothers1 the most successful covering is the one which offers the greatest resistance to the air4 ,the pressure of the air upward under the planes tends to force its way through the meshes of even the finest cloth4 ,the addition of a coat of varnish will prevent this leakage4 ,a light parchment will also be found effective4 ,it will be well to experiment with a variety of coverings4 ,a very light1 serviceable frame may be made for your motor-base by using hollow shafts or sticks4 ,procure a very thin1 light wood1 such as is used for veneering1 and after cutting it carefully into strips1 glue them together to form a hollow shaft about an inch square4 ,although the shell may be only one sixteenth of an inch thick1 the frame will be found strong enough for all practical purposes4 ,a hollow frame of this kind will save several ounces of weight4 ,the builder of aroplane models will find a good friend in aluminium4 ,it is strong enough for all purposes of the model air-ship and1 even when used freely1 adds almost nothing to the weight4 ,the metal costs ninety cents a pound1 but it is so light that1 at this rate1 it will be found a very cheap material4 ,comparatively thick pieces may be used for braces or for angles1 thus making the frame absolutely rigid1 while adding but a fraction of an ounce to the weight4 ,the metal1 being comparatively soft1 is easily worked1 and simple castings may be made at little expense4 ,many builders of aroplanes waste time and ingenuity quite unnecessarily in constructing sets of wheels for carrying their models4 ,the time would be better employed in looking to your planes4 ,the amount of friction saved by attaching wheels1 even good ones1 to your model1 is after all very trifling4 ,should the wheels jam or stick1 which is likely to be the case with such small models1 they are worse than skids1 and besides1 add appreciably to the weight4 ,a light skid is better than a clumsy wheel4 ,if your model fails to rise from the ground1 the fault is not at all likely to be in the skids1 but in the thrust or lifting-surface4 ,an excellent plan for guiding the flights is to add square frames of soft lead wire to the front or cutting-edge of your front planes4 ,bend a piece of wire to form three sides of a square1 each two or three inches long1 and fasten the loose ends to the plane4 ,by bending these up or down1 the center of gravity may be altered at a touch4 ,if your model goes askew1 you may bend one of these up and the other down1 until you get the desired balance4 ,in actual practice1 the soaring- or floating-planes seem to add greater stability to the model and effect to a marked degree the length of the flight4 ,it is difficult to tell exactly why4 ,the planes in passing may create an eddy in the air1 a following wave1 as it were1 which tends to retard the flight1 while the floating-plane smoothes this out4 ,in any event1 here is an experiment well worth trying4 ,,chapter ,,vi ,,simple ,,monoplane ,,models ,of the variety of aroplanes1 there seems to be no end4 ,nature offers a bewildering variety of models in the innumerable birds and insects1 which may be accepted as successful monoplanes4 ,these1 in turn1 may be copied and modified indefinitely4 ,the science of aviation is still so young that there is ample opportunity for invention and discovery for all1 and every new trial adds something to our information1 and carries the science a step nearer perfection4 ,it will be found an excellent plan to build1 once and for all1 a strong well proportioned motor base1 and mount a powerful motor and well modeled propeller4 ,a variety of planes may then be tested out by attaching them to this4 ,the motor base will answer for practically all monoplane forms and many biplane models as well4 ,such a frame should be about three feet in length and carry one or better two motors1 placed side by side4 ,there is as much danger in providing too much lifting-surface in your aroplane as too little4 ,this fault is well illustrated in an exceedingly clever ,french model 7,plate ,i74 ,although the model is well constructed1 and appears ship-shape at first glance1 it nevertheless has far too much surface and will not fly well4 ,if the depth of the wings were reduced fully one half1 it would have a much better chance4 ,the best lifting-planes are those which present a broad front or entering edge1 but with comparatively little depth4 ,the successful flying-machines1 whether monoplanes or biplanes1 use these very wide but shallow planes forward4 ,the theory is of course that the air is caught for an instant beneath the plane and before it has a chance to slip off the sides1 the wing has caught its very slight supporting power and moved on to new and undisturbed air4 ,with this rule in mind examine the model's front plane once more4 ,it will be seen that1 as the air is caught under this broad surface1 it will try to escape in all directions and set up currents of air4 ,instantly the broad plane loses its balance and tilts to one side or the other4 ,no weighting of the plane can overcome this4 ,if the plane were forced through the air at a very high speed a steady flight might be possible1 but it is useless to try to overcome this tendency to tip and wabble4 ,the planes again are badly designed4 ,a perfectly straight front or entering edge gives the best results4 ,a certain stability is gained by curving the front plane slightly1 this will be discussed later1 but there is no excuse for the semicircle described in this case4 ,every inch of surface cut away from the front edge of the plane directly reduces its lifting power4 ,the arrow like form of the rear plane does not matter because this is a stability plane1 not a lifting plane4 ,in this case the rear plane is twice the size it should be4 ,illustration3 ,,plate ,i4 ,a ,clever ,folding ,model4 ,the ,wings ,are ,broader than ,need ,be4 ,the propeller of this model is much too small1 even if the size of the planes was correct4 ,it is well placed however at the front of the model where it may turn in undisturbed air4 ,the passage of these large planes1 or any planes for that matter1 is likely to cut up the air just as a ship churns the water into a wake behind it and the propeller does not work effectively in these eddies4 ,the motor seems powerful and well braced1 although it might be made even longer by carrying it to the extreme rear4 ,several very useful ideas may be borrowed from the construction of the frame of this model4 ,it is made entirely of metal1 so jointed that it may be folded up into very compact form like an umbrella4 ,the amateur model builder should not attempt anything so complicated1 but an old umbrella frame may be used with good results in building a rigid frame4 ,use the steel rod of the umbrella as a backbone1 and cut away the ribs you do not need4 ,the others may be bent into various shapes to form the front or sides of the planes1 the skids or braces4 ,such a construction is light and perfectly rigid4 ,a very effective monoplane may be made by curving the front and rear edges of the forward plane1 while keeping the rear or stability plane rectangular in shape 7,plate #b74 ,the curve of this model may be imitated to advantage1 as well as the general proportions4 ,such a plane is less likely to be deflected by air currents than a straight entering-edge and insures longer and steadier flights4 ,should you be troubled by your model twisting from side to side in flight try curving the front edge of the forward plane4 ,this model is one of the easiest to make and is an excellent one for beginners4 ,build the two planes separately making the larger one about thirty inches in width and ten inches in depth1 and the second one fifteen inches in width and ten inches in depth4 ,the curved sticks may be worked up by using bamboo or dowel-sticks1 soaking them in water and fastening them in a bowed position while damp and leaving them to dry4 ,it may be found a good plan to use a heavier stick for the rear edge of the plane to gain stability4 ,a single stick about one half an inch in diameter may be used for the backbone4 ,it will be found an excellent plan to attach the planes lightly to the main frame so that they may be adjusted before fixing them finally in position4 ,place them in the position shown in the accompanying photograph1 and move them up and down until the flights are all that you expect1 when they may be fastened for good and all4 ,the bracing of this model is excellent and may be safely imitated4 ,it enables one to tune up either plane and fix them rigidly in position4 ,the propeller is very properly placed forward although it appears to be rather small4 ,it is unnecessary to bother with any vertical rudder for this model since the curve of the front plane insures a reasonably straight flight4 ,a popular ,french model which may be easily imitated consists of curved planes both front and rear 7,plate #c74 ,the curve of the planes is too complicated to be carried out in wood1 but may be readily formed by bending a stiff wire to the desired shape4 ,the front plane should be about twelve inches in width and four inches in depth4 ,the rear should be about half this size and of the same form4 ,the planes may be readily mounted on a small dowel stick4 ,a small propeller and a motor a foot in length will answer4 ,a small semi-circular fin should be set below the rear plane to act as rudder4 ,first cover the frames with a stiff paper and after you have succeeded in adjusting it1 this may be replaced by cloth4 ,the model will not fly far1 or very steadily1 but it is interesting to practice with4 ,the balance of the model is open to criticism2 for the center of gravity appears to be too far forward4 ,illustration3 ,,plate ,,ii4 ,a ,model ,aroplane ,worth ,imitating4 ,the simplest of all models to build1 and not the least interesting1 is the small paper monoplane 7,plate #d74 ,the planes which are slightly curved are formed of a stiff card which will hold its shape when bent into position4 ,these may be attached to the main stick by inserting an edge into a groove in the stick and glueing in place4 ,it is not well to construct these more than six inches in width over all4 ,one of the simplest monoplanes to construct is formed of a broad rectangular forward plane with a fan-shaped stability-plane at the rear 7,plate #e74 ,this is a ,french model which is said to have flown long distances2 that is to say1 #cjj feet or more4 ,it has several very interesting features4 ,in the first place the combined area of its planes is doubtless greater than that of any other model here described4 ,the vertical rudder which looks very shipshape and effective is very easy to build and the frame illustrates several new principles4 ,the frame or motor-base may be made of heavy dowel sticks or light lath as indicated in the photograph4 ,it will be found simpler to avoid tapering the frame at the rear by merely constructing a stout rectangular base with a length two and one half times its width4 ,the forward plane is slightly bowed or flexed4 ,it will be found a good plan to construct the frame for the base and then bow a light strip at either end against the edge4 ,by fastening the covering to these curved strips a smooth curved surface may be obtained4 ,the rear stability-plane may be stretched over a fan-shaped frame of strips or lath which is in turn fastened to the motor-base4 ,another plan is to attach the front and rear edges of the plane1 the rear one being slightly longer1 and stretch the covering over these leaving the sides free as in the photograph of the accompanying model4 ,the vertical rudder is very simple1 consisting of a piece of dowel stick sunk in the rear frame to which a rectangular piece of cloth is attached the front corner being pulled taut4 ,the spread of the planes appears to be considerably greater than needs be4 ,since the front plane is flexed it may be reduced one third or even one half in depth without reducing its lifting quality2 although in this case it should be placed nearer the stability plane4 ,this reduction would1 of course1 make an important saving in the weight of the craft4 ,so large a model calls for two propellers which will prove more effective at the front rather than the rear of the machine4 ,it might be well to carry the motors further back than has been done in this model thus gaining additional power4 ,since the model is expected to rise unaided from the ground the question of the skids is very important4 ,the design followed in the model is excellent4 ,the front of the frame is supported by legs consisting of inverted triangles built of dowel sticks attached to the frame4 ,the axle connecting the two runs on small wheels1 such as may be borrowed from a toy automobile4 ,the rear of the frame rests on a simple skid made of curved reed4 ,these supports place the model at an angle which should enable it to rise easily without loss of power4 ,there is a great deal of satisfaction in working on so large a model1 the parts may be made stronger and there is less likelihood of its getting out of order4 ,now turn from these broad planes to the rather slight model 7,plate #f71 and the faults of its proportion are at once obvious4 ,the front plane is much too far back for stability4 ,such a model will glide fairly well1 and1 if the motor be powerful it will rise quickly1 but a steady horizontal flight is out of the question4 ,the size of the planes seems perilously small1 and yet if they be well shaped and spaced they will prove large enough4 ,this is just the sort of model a beginner is likely to make1 and therefore serves a very useful purpose in pointing a lesson4 ,illustration3 ,,plate ,,iii4 ,an ,ingenious ,french ,model ,made of ,umbrella ,wire4 ,it is not without its good points4 ,the front plane has been carefully flexed and attached to the motor frame at a good angle4 ,an interesting experiment has also been made in carrying the edges of the front plane a trifle behind the rear edge1 thus making for stability4 ,the vertical rudder above the rear stability-plane is well placed1 although it appears rather small4 ,the skids upon which the model rests and the proportion of the front to the rear elevation are excellent4 ,it is a first rate plan in building such a model to attach the front plane temporarily to the motor-base1 and move it back and forth in the trial flights until the best spacing has been found4 ,,chapter ,,vii ,,elaborating ,,the ,,monoplane ,it is surprising to find how far the pure monoplane form has been developed by the builders of model aroplanes4 ,it is no exaggeration to say that they have carried some principles of construction even further than the builders of the large man-carrying monoplanes4 ,since a model is so easily built1 and costs so little1 it is of course possible to experiment with all sorts of new forms4 ,a great many of these will doubtless prove to be all wrong1 but some are certain to be valuable discoveries4 ,in future years1 when the aroplane has been perfected and perhaps plays an important part in commerce1 sport and warfare it will probably be possible to trace back many of its improvements to the model aroplanes designed1 built and flown by ,american boys of to-day4 ,a beautiful model of a pure monoplane form carefully elaborated is shown in ,plate #g4 ,in this case increased stability is obtained by throwing out additional planes both to the front and rear4 ,it may appear at first glance that these stability-planes are very small compared with the broad soaring-plane1 but they have not proved so in flight4 ,it will be remembered that the elevating-plane of the ,wright machine is very small compared with the spread of the main wings4 ,there is besides a great advantage in placing the stability plane well forward since it makes it possible to build an unusually long motor-base and install longer and more powerful motors4 ,the main plane is one of the best examples of construction work to be found among all these models4 ,it is well proportioned and the curve has been skilfully drawn4 ,the plane is made unusually rigid by a series of supports or braces run both horizontally and vertically4 ,such a plane calls for considerable time and patience1 but it will well repay the builder by the long and steady flights it insures for the model4 ,in adding ribs to a large plane of this kind a convenient material may be prepared by splitting up thin wooden plates or dishes1 such as you buy at the grocers for a penny4 ,the strips obtained in this way may be easily glued or tied to the edge of the plane and shaped as desired4 ,a long1 straight flight is insured for this model by equipping it with three vertical rudders or guiding-planes4 ,the first rudder is well placed above the front plane4 ,the second performs a good service beneath the main plane1 while the third is carried unusually far back behind the propellers4 ,the problem whether a rudder is more effective above or below the planes is very ingeniously solved in this case by placing them in both positions4 ,an interesting principle is involved in placing the rear rudder4 ,by fixing it far behind the center of gravity of the model a considerable leverage is obtained1 and a small1 light rudder becomes more effective in this position than a much larger plane placed forward4 ,these rudders are built so that they may be easily turned from side to side and fixed rigidly at any angle4 ,illustration3 ,,plate ,,iv4 ,one of the ,simplest of ,aroplanes to ,construct4 ,still another interesting feature of this model is the design of the skids4 ,the model is supported at an angle which enables it to rise easily4 ,these skids are besides arranged with shock-absorbers1 simply constructed with elastic bands1 which enable them to take up the shock on landing and thus protects the machine4 ,this is an interesting field of experiment and a little care in building these skids will save many a smash-up4 ,it cannot be too often stated1 that the supporting power of the planes depends far more upon their shape than their size4 ,a remarkably effective model may be made with planes1 which are little more than blades 7,plate #h74 ,the planes1 in this case1 are made of white wood1 slightly curved4 ,the front or entering edge is very sharp1 while1 at the rear1 a thin strip of shellaced silk is glued1 thus forming a good soaring blade4 ,the front plane is a counterpart of the first1 except that it is smaller4 ,the only stability plane is a thin1 knife-like strip placed vertically just before the rear plane4 ,the model is mounted on skids4 ,it is driven by a small propeller placed far back of the center of gravity4 ,it is probably the easiest as it is the smallest of all models to construct1 and will fly for more than three hundred feet4 ,in building this model it will be found a good plan to bend the strips of wood for the planes by steaming them over a kettle4 ,allow the steam to play on the under or concave side of the plane4 ,when dry the plane will retain its shape4 ,the front or entering edge should be trimmed away to a sharp line and sand-papered perfectly smooth4 ,the front corners of the planes should be slightly rounded while the rear edges are kept straight4 ,the forward plane should be tilted slightly upward to enable it to rise1 but at an angle of less than thirty degrees4 ,the secret of the remarkable flights of this model probably lies in the smoothness of its planes and the absence of irregular parts which offer a resistance to the air4 ,an interesting field of experiment1 as yet almost untouched1 lies in the triangular1 or narrow-prowed forms of aroplanes 7,plate #i74 ,the theory of this model is1 that a triangle entering the air end-wise1 will meet with less resistance than when presenting a broad1 entering edge4 ,the model is1 frankly1 an experiment1 although it has been found to have unexpected stability1 and flies well4 ,its central planes1 joined at right angles1 is supported by two1 lateral1 stability-planes1 radiating backward from the front of the model4 ,the aroplane is drawn1 not pushed1 through the air1 by double propellers1 and is steered by an angular guiding-plane at the rear4 ,the planes are mounted upon a triangular frame1 which runs on wheels1 two being set forward and one aft4 ,the planes1 taking advantage of the dihedral angle1 seem to rest upon the air1 which makes for stability4 ,in actual practice1 however1 the planes in this particular model have been found to be too narrow4 ,the question naturally arises as to the effect of reversing this model and turning the dihedral angle of the central plane1 into a tent effect4 ,as a matter of actual experience1 the model flies almost equally well upside down4 ,in many of the early attempts to build aroplanes the wings or planes were tilted sharply upward from the center thus forming what is known as a dihedral angle4 ,this form served to lower the center of gravity and1 it was thought1 made for stability4 ,the ,wright ,brothers found that this plan1 although it lowered the center of gravity1 caused it to move from side to side like a pendulum1 and therefore abandoned it in favor of the flat curved wing which have been so generally imitated4 ,now this model returns to the old principle of the dihedral model1 but treats it in a new way4 ,by building the model with three planes1 each with the dihedral angle1 the center of gravity has been lowered and1 at the same time1 the oscillation has been greatly reduced4 ,illustration3 ,,plate ,v4 ,too ,large for ,beginners1 but ,will ,make ,long ,flights4 ,the narrow-prowed form of this model is also very interesting and its principle may well be copied4 ,all of the successful monoplanes aloft to-day1 the ,bleriot1 ,santos ,dumont1 ,antoinette and others are driven with their larger or soaring planes forward and their smaller stability-planes in the rear4 ,the day may come when these machines will be reversed4 ,the model before us may point the way to a great improvement in the building of air-craft4 ,it is an important principle for the builder of model aroplanes to bear in mind4 ,in the present state of model aroplane building1 the longest flights are made with an adaptation of the monoplane forms4 ,an excellent model is shown in ,plate #aj4 ,the dihedral1 or ,v shape of the planes gives them greater supporting power than others in the horizontal position4 ,the stability plane beneath is particularly recommended1 since it utilizes the frame already in position and does not add to the weight of the model4 ,the rear of this plane1 which is hinged1 is easily adjusted4 ,the planes of this model are especially interesting4 ,they are made of silk1 laid over frames of dowel sticks1 and each pair is held tightly together by the simple device of connecting them with elastic bands1 attached to clasps4 ,the wires running to the corners of the planes1 are fastened to small brass rings which may be slipped over the sticks or posts in the center of the frame1 which makes them very simple to adjust4 ,it will be noticed that the rear part of each plane swings freely1 and is kept in place only by corset steels1 used as ribs1 which are sewn into the cloth4 ,these floating or soaring blades1 as they are sometimes called1 insure longer flights4 ,with such a model there is little danger of building a too powerful motor4 ,by increasing the size of the wings1 and careful weighting1 a surprising amount of power may be applied to such a model without rendering it unstable4 ,this is of course a great advantage in such a model1 since it lends itself to longer flights and the installation of comparatively heavy motors4 ,when you find yourself with a model of this design in good working order1 experiment by binding the wings or planes at the middle to form an arched surface like the wings of a sea gull4 ,the flying radius of some of these models has been increased fully fifty per cent by this simple expedient4 ,an interesting modification of this form 7,plate #aa7 is provided with rigid wings1 and is driven by a single propeller4 ,the very simple but effective method of bracing the wings1 may be studied to advantage4 ,the skids are well designed4 ,in still another type of this general monoplane form 7,plate #ab7 the propeller is placed in front of the planes1 and the rubber motor runs below the main bar4 ,the wheels supporting this model are particularly well made4 ,a very serviceable1 little monoplane form may be made by making the rear upper plane adjustable 7,plates #ac-ad74 ,the front plane is ,v-shaped and is unusually stable for so light a model4 ,by tilting the rear plane up or down1 a good level flight may be obtained4 ,the frame1 in this case1 is made of wire4 ,the propeller is placed well behind the rear plane1 thus bringing the center of gravity well forward to balance the angle of the rear plane4 ,the blades of the propeller are made of twisted wood1 which is not to be recommended1 since it is likely to lose its shape4 ,in ,plates #ae-af we have a well thought out little monoplane1 which well repays study4 ,the propeller is set forward of the lifting plane which is the larger of the wings4 ,the rear plane may be tilted up or down4 ,the rudder1 which is also adjustable1 is set below it4 ,the arrangement of skids is excellent1 enabling it to rise from the ground with little loss of friction4 ,the method of flexing the front plane may well be imitated4 ,illustration3 ,model shown in ,plate ,v4 ,ready for a ,flight4 ,a good working idea of the aroplane is clearly shown by the builder of the biplane with triangular wings 7,plate #ag74 ,his model is not successful and will not fly1 yet it embodies several good features4 ,the biplane form of the lifting plane is excellent in itself as we have seen in earlier models4 ,the spacing of the two planes is good1 and the bracing of the model throughout is well planned4 ,the triangle does not make a good soaring plane even when its broad side is made the entering edge4 ,the triangle serves well enough however for the rear stability plane4 ,the chief fault of the model is that it is much too large4 ,the motor although well proportioned is much too weak to propel so large a frame4 ,an interesting variation from the common type of aroplane is made by varying the angle of the sides of the planes 7,fig4 #ah74 ,here is a well constructed model1 and1 with a single exception1 fairly well proportioned4 ,the mistake1 and it is likely to prove a serious one1 is in the size of the vertical rudders4 ,they are well placed above the main plane1 but their size is likely to defeat the purpose for which they were designed and knock the model off its course rather than keep it steady4 ,it is a question again if one of these rudders would not serve the purpose better than two and thus minimize weight and resistance4 ,the best point of this model is the ingenious method of enlarging the surface of the planes without increasing the size of the planes or adding to their weight4 ,this is done by cutting the covering of the planes at an angle and keeping the entire surface taut by bracing4 ,it is of course very important that the cloth should be held tight without wrinkling4 ,the plan of having the wings taper slightly outward is good4 ,such a model combines more lifting surface with less weight than any other model of this general group4 ,,chapter ,,viii ,,building ,a ,,biplane ,every one knows1 of course1 that the box-kite flies better than a plane surface1 and many believe that the box or cellular type of aroplane has a similar advantage over the monoplane4 ,the enclosed end keeps the air from slipping off the edges of the plane1 and makes for stability4 ,there is all the difference in the world1 or rather in the air1 between an actual flight and the movement of a model aroplane4 ,the aviator1 by flexing his planes1 and adjusting his rudders fore and aft1 may balance his craft to suit the air currents4 ,in the model aroplane1 the adjustment must be made before starting once and for all4 ,several interesting principles are involved in the cellular or box form of aroplanes which will well repay study 7,plates #ai-bj74 ,in disturbed air1 which is of course the usual condition of the atmosphere1 the cellular model is likely to be deflected1 and since the elevating plane or planes cannot be adjusted1 it will soon fall off its course4 ,such models are easy to construct1 and any one who has built a monoplane will have little difficulty with them4 ,no attempt is made to flex the planes4 ,the cellular type must be equipped with a lifting-plane forward1 which may be easily adjusted to any angle1 and held in position4 ,it is indispensable that you have two propellers placed aft behind the main plane4 ,the model may be made much more effective by adding a third stability-plane or rudder at the rear4 ,it may be either vertical or horizontal and should be easily adjusted4 ,the models illustrated1 herewith1 are very simple forms and clearly indicate the necessary frame work4 ,it will be found that these models require considerable ballast1 skilfully distributed4 ,illustration3 ,,plate ,,vi4 ,a ,model with ,both ,good and ,bad ,features4 ,in building these cellular forms select some light lath for the frame rather than dowel sticks4 ,it will be necessary to join many of these together at right angles1 and the curved stick will be found difficult to work4 ,for each box cut four sticks the desired width1 and eight sticks the depth of your plane4 ,the box should be almost exactly square so that all these shorter sticks should be the same length4 ,now build your box by nailing and glueing these sticks together1 taking great pains to have it symmetrical4 ,should a single one of these sticks be too long or too short it will throw the entire frame out of plumb and make it next to impossible to get a straight flight4 ,in most of these models the front or rear stability-planes are made exactly like the larger frame only much smaller4 ,when the frames are completed and thoroughly dry and smooth1 stretch the cloth covering tightly over them by drawing it lengthwise1 all the way around4 ,by using a single piece of cloth it will be found easier to pull it together and hold it tight and smooth4 ,it will be found a good plan to touch the outer edges of the frame you are covering with glue just before covering4 ,when the glue dries the cloth will thus be held firmly in position4 ,the cloth may be fastened to the outer edges by glueing or sewing4 ,a simple but effective plan for mounting the stability-planes is suggested by the models here illustrated4 ,the frame of the motor-base may be made the width of the smaller frame and fastened between the two sticks4 ,it should be left free so that it may be tilted up or down and fixed in any position4 ,if the rear stability-plane is to serve as rudder it should of course be mounted vertically so that it may be turned to right or left4 ,be sure to make your frame sufficiently strong and rigid4 ,a light frame which will vibrate when the motor turns or is shaken by the wind will be found very troublesome indeed4 ,the cylindrical forms of planes 7,plate #ba7 carries the foregoing principles a step further4 ,a surprising degree of stability is obtained by thus enclosing the air1 and by throwing out several lateral stability-planes fore and aft4 ,the models may be constructed of heavy wire1 ordinary umbrella wire will answer the purpose1 and may be readily bent4 ,the planes in the accompanying model are merely suggestive4 ,the broad planes placed forward1 well above the diameter1 promise well1 but the rear wings appear unstable and small for the other surface4 ,the forward or lifting-plane is again1 much too narrow4 ,the cylindrical form is equipped with a double propeller1 one before and the other in the rear1 both mounted on a bar1 which forms the exact axis of the cylinder4 ,this adjustment will give you a very pleasant surprise4 ,the vibration and torque of the two propellers seem to equalize one another1 and the thrust is much more steady than in the case of a single screw4 ,the thrust is not only double1 in this way1 but the gain for stability is surprising4 ,the model should be mounted on skids to assist it in rising1 and to take up the force of the impact on landing4 ,the double propeller1 mounted on the same shaft1 may be used successfully in many models4 ,a very simple monoplane form 7,plate #bb7 may be equipped in this way4 ,if two or more planes be mounted between the propellers1 an astonishing soaring quality may be had4 ,it is an excellent plan to fasten the planes to the frame at first by rubber bands1 so that they may be pushed up or down readily1 and adjusted and weighted to suit the conditions4 ,there is danger in this form1 however1 that the plane will turn completely over in its flight1 although this will have little effect upon the thrust or direction4 ,the model is exceedingly simple to make4 ,the propellers should not be too large1 not more than twice the diameter of the planes at most4 ,the two propellers must1 of course1 be turned in opposite directions1 to correct the twisting tendency4 ,illustration3 ,,plate ,,vii4 ,a ,good ,example of ,careful ,designing and ,workmanship4 ,should you construct a motor-base of this kind with propellers at either end it will be found interesting to experiment by attaching planes of different shapes and sizes4 ,it requires very little surface to keep such a monoplane afloat4 ,instead of the circular and elliptical plane placed lengthwise1 as in the accompanying model1 try the effect of larger circles and broader ellipses1 placing the latter sideways4 ,this may be varied by using small rectangular planes with the corners rounded off4 ,sooner or later you will hit upon a shape of plane and a spacing which will give you good1 steady flights of surprising length4 ,it has been suggested that a good motor-base be built with double propellers and the various forms of planes tested out upon it4 ,let us carry this idea further and1 now that we have had some experience in building aroplane models1 construct a quadruple motor-base2 that is a motor-base with four strands of rubber bands and four propellers1 two forward and two aft4 ,the four would of course have to be very nicely balanced4 ,the two sets of propellers if carefully set up would tend to correct one another1 as we have seen in the cylindrical and other double propellers thus giving a very steady flight4 ,the increased speed of such a motor would carry any good model at a much higher rate of speed than any of the present forms4 ,there is a very simple rule to be remembered in building all biplanes1 regarding the spacing of the planes4 ,the distance between the super-imposed planes should always be equal to the width of the planes themselves4 ,a beautiful model 7,plate #bc7 is here reproduced1 to show how not to space your planes4 ,in all other respects the model is excellent4 ,the planes themselves are beautifully constructed and scientifically curved4 ,it is interesting to note1 in this case1 that the front and rear sets of planes would be much too far apart were they flat surfaces1 but being flexed as they are1 their supporting power is greatly increased4 ,by placing them so far apart1 a longer and more powerful motor may be used4 ,the rudders1 both fore and aft1 are adjustable1 and appear very effective and shipshape4 ,the method of tuning up the planes in this model is especially to be recommended4 ,from a post1 placed at the center of the planes1 wires are run to the corners which holds the frame perfectly taut4 ,for the main frame1 or backbone1 a metal tube has been used which greatly adds to the appearance of the model4 ,this aluminium tubing may be bought cheaply and will serve admirably for this purpose4 ,the most popular of all models1 among amateur aronauts in ,america1 at least1 is the ,wright machine 7,plates #bd-be74 ,the opinion is ventured that this is due more to the attractiveness of its lines and the pride we all take in its wonderful achievements1 than to its actual flying ability as a model4 ,the most perfect of these models will rarely fly more than a hundred feet4 ,they will be found exceedingly difficult to weight and adjust so that they will maintain their course in a disturbed air current4 ,the planes of these models are usually made separate from the motor base4 ,the shafts of the propellers1 with the rubber motors and skids1 are built up in a single piece4 ,this plan has the advantage of making the planes adjustable so that they may move backward or forward as desired4 ,the model leaves the ground from a base1 much the same as the rail used by the large ,wright machines4 ,some models are even started by the propulsion of a rubber band attached to the frame1 which is pulled back and released1 like the old-fashioned sling shot4 ,illustration3 ,,plate ,,viii4 ,an ,effective ,model with ,wooden ,wings4 ,,chapter ,,ix ,,combining ,,monoplane ,,and ,,biplane ,,forms ,although the regular biplane form is exceedingly difficult to manage in small models1 there is great advantage in combining it with the monoplane forms 7,plate #bf74 ,the biplane makes an excellent lifting plane1 and when the model combines with it a broad monoplane for stability1 surprisingly long flights may be made4 ,the model here illustrated has flown #bah feet #f inches4 ,despite its size1 the model is exceedingly light4 ,it is made almost entirely of dowel sticks braced with piano wire4 ,still another advantage of the biplane form is the action of the supporting surface when it comes to descend4 ,the model settles easily to the ground1 in contrast to many monoplane models which come down with a dislocating shock4 ,the skids of this model are simple and effective4 ,in a model of this form it is obviously best to have the propellers drive rather than pull it4 ,an ingenious young aronaut has reversed the above order and placed his biplane in the rear1 using the monoplane for lifting 7,plate #bg74 ,his model is unusually large1 having a spread of four feet4 ,the biplane is square1 with lateral stability planes on either side4 ,the elevating planes appear small in proportion1 but they serve to keep the craft on an even keel4 ,the most striking feature of this model is its extreme lightness4 ,although unusually large1 it weighs but nine ounces4 ,the frame1 except for the braces is built of reed4 ,the planes are covered with parchment4 ,the model is driven by two rather small propellers4 ,the position of the propellers will appear1 at first glance1 to be rather low1 but it must be remembered that the extreme lightness of the model brings the center of gravity very far down4 ,the model has flown more than two hundred feet4 ,illustration3 ,,plate ,,ix4 ,an ,interesting ,experiment ,along ,new ,lines4 ,the stability of the models thus combining the monoplane and biplane forms comes as a surprise4 ,both the models in question rise easily from the ground1 which is more than can be said of many aroplanes big or little1 and once aloft maintain a steady horizontal flight1 which is still more unusual4 ,an interesting field of experiment is suggested by these combinations4 ,these successful experiments have been made with perfectly flat planes4 ,suppose now we try them out with flexed planes4 ,if the stability thus gained may be combined with the increased soaring quality of the curved plane1 we may be on the way to making some remarkable flights4 ,in the summer of #aiji a number of boys built and flew model aroplanes in ,new ,york1 when many interesting and well constructed models were brought out1 and the longest flight was only sixty feet4 ,less than one year later the same boys succeeded in flying their machines for more than two hundred feet4 ,the new models were no larger1 the motors no more powerful1 but the machine had become more shipshape and efficient4 ,it is reasonable to suppose that each year will bring a similar advance4 ,,chapter ,x ,,faults ,,and ,,how ,,to ,,mend ,,them ,your model1 perhaps a beautiful one1 finished in every part1 may twist and tip about as soon as it is launched and quickly dart to the ground4 ,the fault is likely to be in the propeller1 being too large for the size and weight of the machine4 ,this may be remedied by adding a weight to the front of the machine1 by wiring on a nut or piece of metal4 ,should this fail to steady the aroplane1 the propeller must be cut down4 ,when your propeller is too small the machine will not rise from the ground1 or1 if launched in the air1 will quickly flutter to earth4 ,if the model on leaving your hand1 with the propeller in full motion1 fails to keep its position from the very start1 the blade should be made larger4 ,there is no use in wasting time and patience over the machine as it is4 ,many a beginner1 with mistaken zeal1 constructs a too powerful motor4 ,the power in this case turns the propeller too swiftly for it to grasp the air4 ,it merely bores a hole in the air and exerts little propelling force4 ,an ordinary motor when wound up one hundred and fifty turns should take about ten seconds1 perhaps a trifle longer1 to unwind4 ,it is a good plan to time it before chancing a flight4 ,bad bracing is another frequent source of trouble4 ,the planes should be absolutely rigid4 ,test your model by winding up your motor and letting it run down while keeping the aroplane suspended1 by holding it loosely in one hand4 ,if the motor racks the machine1 that is1 if the little ship is all a-flutter and the planes tremble visibly1 the entire frame needs tuning up4 ,it is impossible for an aroplane to hold its course if the planes are in the least wabbly4 ,the braces should be taut4 ,a loose string or wire incidentally offers as much resistance to the air as a wooden post4 ,the flight of your model aroplane should be horizontal1 with little or no wave-motion4 ,your craft at first may rise to a considerable height1 say fifteen or twenty feet1 then plunge downward1 right itself1 and again ascend1 and repeat this rather violent wave-motion until it strikes the ground4 ,to overcome this1 look carefully to the angle or lift of your front plane or planes and to the weighting4 ,the explanation is very simple4 ,as the aroplane soars upward1 the air is compressed beneath the planes1 and this continues until the surface balances1 tilts forward1 and the downward flight commences4 ,your planes should be so inclined that the center of air-pressure comes about one third of the distance back from the front edge4 ,the center of gravity of each plane1 however1 should come slightly in front of the center of pressure4 ,after all1 the best plan is to proceed by the rule of thumb1 and tilt your planes little by little1 and add or lessen the weight in one place or another1 until the flight is horizontal and stable4 ,if your aroplane does not rise from the ground1 but merely slides along1 the trouble is likely to be in your lifting plane4 ,tilt it a trifle and try again4 ,the simplest way to do this is to make the front skids higher than those at the back4 ,if the front skids are too high1 the plane will shoot up in the air and come down within a few feet4 ,the most carefully constructed model is likely to go awry in the early flights4 ,the propeller seems to exert a twist or torque1 as it is called1 which sends it to the right or left1 or up or down1 even in a perfectly undisturbed atmosphere4 ,it is assumed that your model is symmetrical4 ,an aroplane not properly balanced1 which is larger on one side than the other1 or in which the motor is not exactly centered1 cannot1 of course1 be expected to fly straight4 ,however1 to be on the safe side1 go all over the machine again4 ,measure its planes to see that the propeller is in the center4 ,hold it up in front of you right abeam1 and test with your eye if the parts be properly balanced4 ,if it still flies badly askew1 flex the planes by bending the ends up or down very slightly by tightening or loosening the wire braces running to the corners4 ,at the same time add a little weight to counteract the tipping tendency4 ,a nut or key may be wired on the edge which persists in turning up4 ,it may require much more weight than you imagine4 ,the difference should begin to show at once4 ,even after a model appears to work fairly well as a glider1 the addition of the motor may so change the center of gravity that it will 8cut up0 dreadfully4 ,it will be well to leave your planes loose so that they may be shifted back and forth and not fasten them till you have tried out the motor4 ,if you followed the plan suggested of fastening the plane to the central frame by crossing rubber bands over it1 you can easily adjust them4 ,if the model tends to fly upward at a sharp angle1 slide the front plane forward an inch1 and try another flight4 ,there is an adjustment somewhere which will give the model the steady1 horizontal flight you are after4 ,some models will refuse to rise and swing around in an abrupt circle the moment the motor is turned on4 ,this may be caused by the propeller being much too small for the motor4 ,after looking over all the photographs of the models shown in these pages you will gain an idea of the proper proportion1 and be able to tell offhand if the propeller is out of proportion4 ,a small propeller revolving very rapidly1 or racing1 is likely to give the model a torque1 even if it be otherwise well proportioned4 ,don't try to remedy this with rudder surfaces1 but change your propeller1 or your motor1 or both4 ,illustration3 ,,plate ,x4 ,an ,excellent ,monoplane ,capable of ,long ,flights4 ,when your aroplane turns in long1 even curves to one side or the other1 look to your rudder surface4 ,turn it to one side or the other1 just as you would in steering a boat4 ,it is1 of course1 obvious that it must be kept rigidly in position4 ,if a slight turn of the rudder does not straighten out the flight1 you probably need more guiding surface1 and the rudder must be enlarged4 ,if the model still continues to turn away from a straight line1 tilting as it does so1 try a little weight at the end of the plane which rises4 ,the commonest of all accidents to aroplane models is the smashing up of the skids on landing4 ,a model will frequently rise to a height of fifteen or twenty feet1 and the shock of a fall from such an elevation is likely to work havoc in the underbody4 ,there is no reason1 however1 why your model should not come down as lightly as a bird from the crest of the flight wave4 ,the model1 when properly proportioned1 weighted1 or balanced1 will settle down gradually and not pitch violently4 ,it is these quick darts to earth which cause the worst disasters4 ,a model should have sufficient supporting surface to break its fall when the motor runs down1 at any reasonable elevation4 ,if the model aroplane falls all in a heap1 as soon as the motor slows down1 it will be well to look to this and perhaps increase the size of your planes4 ,as a general rule1 the biplanes or the models in which the double planes have been used1 either for lifting or soaring planes1 will settle down more gradually4 ,the lateral planes1 whatever their position1 also lend valuable support when the critical time comes in the descent4 ,your model is not perfect until it falls easily at the end of the flight4 ,illustration3 ,detail of ,model ,shown in ,plate ,x4 ,under perfect condition1 in absolutely undisturbed air1 an aroplane may be made to come down so lightly that no bones1 even the smallest1 will be broken4 ,a gust of wind1 however1 may ruin all your calculations and bring the aroplane down with a dislocating shock4 ,the skids must be designed to meet extreme conditions1 the worst that can possibly befall4 ,it has been pointed out that these skids or supports should be high enough to give the propeller clearance so that the propeller blades will not touch the ground4 ,by using a light flexible cane for the purpose1 and bending them under1 a spring may be formed which will take up the shock of a violent landing4 ,some builders go further and rig up the skids with braces of rubber bands to increase this cushion effect4 ,a variety of constructions are shown in the photographs of the various models4 ,your skids should enable your model to withstand any ordinary shock of landing1 without breakage of any kind4 ,the life of your motor can be greatly increased by careful handling4 ,the rubber strands are likely to be worn away against the hooks at either end4 ,the wire used for the hooks should be as heavy as possible to keep it from cutting through4 ,be careful that the wire which comes in contact with the rubber is perfectly smooth and flawless4 ,a little roughness or a spur on the wire will soon cut through the rubber4 ,it is a good plan to slip a piece of rubber tubing tightly over the hook and loop the rubber bands of your motor over this cushion4 ,the first break in the rubber bands is likely to come near the center of the strand4 ,a number of loose ends appear4 ,the broken ends should be knotted neatly and the loose ends cut away4 ,if the strands come in contact with any part of the motor base1 a breaking will quickly follow1 and your strands soon become covered with a fringe of loose ends4 ,be careful to tie up all loose ends and trim them away1 since the ends in twisting serve to break other strands4 ,although the finer strands of rubber give the greater thrust1 do not buy them too small1 since they are easily broken4 ,illustration3 ,,plate ,,xi4 ,a ,well ,thought ,out ,monoplane4 ,the length of your motor base beyond the front plane should be carefully calculated4 ,it is very easy1 of course1 to run your shaft too far forward4 ,the center of gravity is easily shifted in this way1 and your model soon becomes unmanageable4 ,an aroplane with this fault will not rise1 but merely pitches forward under the thrusts of the motor4 ,it is almost useless to attempt to balance this by weighting the machine4 ,the front plane should be placed further forward1 and if the lifting surface does not seem sufficient1 cut away the front of your motor base1 once for all4 ,a too short motor base1 on the other hand1 will cause your model to shoot upward at a sharp angle1 and waste much valuable propelling power before it rights itself and takes a regular horizontal flight4 ,in the model aroplane there is only one point where friction affects the flight1 namely1 along the propeller shaft4 ,one can hardly be too careful in the construction of the axle4 ,the thrust of the rubber at best1 is limited1 and this power must be exerted without loss of any kind4 ,a faulty propeller shaft will use up a surprising amount of energy4 ,your rubber motor should unwind to within one or two turns4 ,bear in mind that one of four things is likely to be responsible for your trouble4 ,the planes may not be properly placed on the frame1 they may not be properly flexed1 they are not set at the proper angle of elevation1 or your motor is at fault4 ,watch these points1 and you will soon have your machine under perfect control4 ,in the extremely complicated models it is often difficult to locate the fault4 ,build your model so that these parts may be adjusted in a moment without taking apart4 ,after you have built an aroplane model1 even a very simple one1 the pictures of other aroplanes will have a new meaning for you4 ,every new model you see will give you some new idea4 ,a number of the most successful aroplane models in the country are shown in the accompanying photographs4 ,study these carefully1 and you will learn more from them of practical aroplane construction than from any amount of reading4 ,,part ,,ii ,,the ,,history ,,and ,,science ,,of ,,aviation ,,chapter ,i ,,the ,,first ,,flying ,,machines ,the conquest of the air was not won by a happy accident of invention4 ,long before man learned to fly the science of aviation had to be created by investigation and experiment4 ,at first with very crude attempts1 a great many flying machines had to be built1 and many lives sacrificed in flying them4 ,the exact nature of the invisible air currents and the action of wings and planes1 were to be learned before the delicate mechanism of the modern aroplane was possible4 ,probably no other great invention has required such long and patient preparation4 ,in many ways the aroplane is therefore a greater achievement than the steam engine or the steamboat4 ,when ,watt turned from watching his tea kettle to build his engine1 he applied mechanical principles which had long been in actual use1 and there were many experienced mechanics to help him4 ,robert ,fulton1 again1 when he set up his engine1 found the science of boat-building highly developed4 ,the aviator had no such advantage4 ,he must first of all build a craft which would keep afloat in the most unstable of mediums4 ,a motive power had to be applied to suit these conditions1 and the two must be so attuned that they would work perfectly together when the least slip would mean instant disaster4 ,as we learn to realize these difficulties we will appreciate more than ever how marvellous a creation is the modern aroplane4 ,illustration3 ,,plate ,,xii4 ,a ,good ,example of ,tilted ,planes4 ,man has thought much about flying from the earliest times4 ,the open air has always seemed the natural highway1 and flying machines were invented hundreds of years before anyone dreamed of steamengines or steamboats4 ,the ancient ,greeks long ago spun wonderful tales of the mythical ,daedalus and ,icarus and their flight to the sun and back again4 ,the first practical aviator seems to have been a ,greek named ,achytas1 and we are told he invented a dove of wood propelled by heated air4 ,there is another ancient record of a brass fly which made a short flight1 so that we may be sure that even the ancients had their own ideas about heavier-than-air machines4 ,as far as we may judge from these quaint old records the early aviators attempted to fly with wings which they flapped about them in imitation of birds4 ,about the year #fg ,a4 ,d41 during the reign of the ,emperor ,nero1 an aviator named 8,simon the ,magician0 made a public flight before a ,roman crowd4 ,according to the record1 8,he rose into the air through the assistance of demons4 ,but ,st4 ,peter having offered a prayer1 the action of the demons ceased and the magician was crushed in a fall and perished instantly40 ,the end of the account1 which sounds very probable indeed1 is the first aronautical smash-up on record4 ,even in these early days the interest in aronautics appears to have been widespread4 ,it is recorded that a ,british king named ,baldud succeeded in flying over the city of ,trinovante1 but unfortunately fell and1 landing on a temple1 was instantly killed4 ,in the eleventh century a ,benedictine monk built a pair of wings modelled upon the poet ,ovid's description of those used by ,daedalus1 which was apparently a very uncertain model4 ,the aviator jumped from a high tower against the wind1 and1 according to the record1 sailed for #abe feet1 when he fell and broke both his legs4 ,that he should have attempted to fly against the wind1 by the way1 indicates some knowledge of aircraft4 ,if we may trust the rude folklore of the ,middle ,ages1 the glider form of airship which anticipated the modern aroplane was used with some success a thousand years ago4 ,an inventor named ,oliver of ,malmesburg1 built a glider and soared for #cgj feet1 which would be a creditable record for such a craft even in our day4 ,a hundred years later a ,saracen attempted to fly in the same way and was killed by a fall4 ,the number of men who have given their lives to the cause of aviation in all these centuries of experiment must be considerable4 ,meanwhile the kite and balloon had long been in use in ,china4 ,there is no reason to doubt that kites were well understood and even put to practical use in time of war as early as #cjj ,b4 ,c4 ,a ,chinese general1 ,han ,sin1 is said to have actually signalled by kites to a beleaguered city that he was outside the walls and expected to lend assistance4 ,and a ,french missionary visiting ,china in #afid reported that he had seen the records of the coronation of the ,emperor ,fo ,kien in #acjf which described the balloon ascensions that formed part of the ceremony4 ,the fifteenth century was the most active period in aronautical experiments before our own4 ,a number of intelligent minds worked at the problem and notable progress was made1 although all fell short of flying4 ,even in the light of our present knowledge of aronautics we must admire the thorough1 scientific way the aviators went about their work five centuries ago4 ,many of their discoveries have been of great assistance to our modern aviators4 ,had these investigators possessed our modern machinery1 of which they knew little or nothing1 it is1 very likely they would actually have flown4 ,one of the greatest of these investigators was ,leonardo da ,vinci1 famous as architect and engineer as well as painter and sculptor4 ,to begin at the beginning of the subject1 he dissected the bodies of many birds and made careful1 technical drawings to illustrate the theory of the action of wings4 ,these drawings and descriptions are still preserved1 and even to-day repay careful study4 ,he also calculated with great detail the amount of force which would be necessary to drive such machines4 ,plans were prepared for flying machines of the heavier than air form to be driven by wings1 and even by screw propellers1 which was looking far into the future4 ,illustration3 ,,plate ,,xiii4 ,a ,serviceable ,form ,made of ,wire4 ,among all these early experiments the best record of actual flight was made by ,batitta ,dante1 a brother of the great ,italian poet4 ,in #adef ,dante flew in a glider of his own construction for more than #hjj feet at ,perugia in ,italy and a few years later he succeeded in flying in the same glider over ,lake ,trasimene4 ,the glides made by the ,wright ,brothers while perfecting their machines seldom reached this length4 ,for several centuries it was believed that a lifting screw1 if one could be built1 would supply enough lifting power to support a heavier than air machine4 ,da ,vinci experimented along this line for many years and even built a number of models with paper screws4 ,this form of flying machine is called the helicopter4 ,the plan was then abandoned for nearly five centuries and revived in our own century4 ,the record of all the aviators and their experiments would fill many volumes4 ,the belief that man could learn to fly by flapping wings up and down was not given up until very recently4 ,nearly all the early machines were built on this principle4 ,man can never fly as the birds do because his muscles are differently grouped4 ,in the birds the strongest muscles1 the driving power1 are in the chest at the base of the wings where they are most needed4 ,it is amusing to find that while the birds are always flying before our eyes no one has guessed their secrets4 ,many attempts have been made to wrest their secrets from them by attaching dynometers to their wings to measure the force of the muscles but little has been learned in this way4 ,one scientist calculated that a goose exerts #bjj horse power while another investigator figured out that it was one tenth of one horse power4 ,many of the theories of flight have been quite as far apart4 ,a great variety of false notions about flying had to be tried and from all these failures man slowly learned the road he must follow4 ,,chapter ,,ii ,,developing ,,the ,,aeroplane ,the opening of the twentieth century found the world well prepared for actual conquest of the air4 ,aviation has been developed to an exact science4 ,it had taken centuries of failure to teach man that he could not fly by flapping his wings like the birds but the idea was at last abandoned4 ,the birds were still the models of the heavier-than-air machines1 but man had at last learned to study them more intelligently4 ,the marvellous development of modern mechanics1 especially the building of light and efficient motors1 was also of great importance4 ,the theory of the aroplane was rapidly gaining in favor4 ,it was thought at one time that since no birds weighed more than fifty pounds no flying machine heavier than this could ever fly4 ,some years ago ,hiram ,s4 ,maxim pointed out1 however1 that if we had built our steam engines to imitate the horse1 as we then hoped to build flying machines like the birds1 we would have built locomotives which weighed only five tons1 the weight of an elephant1 which walked five miles an hour4 ,the secret of flight evidently did not lie in closely imitating the familiar forms of flight4 ,so far as man was interested it lay clearly in the soaring flights4 ,when a bird flies with extended wings it does two things4 ,it forms an aroplane which supports its body1 much the same as a kite1 and it operates a propeller for driving this aroplane forward4 ,and so men finally learned to fly by borrowing a single principle from the birds4 ,it is claimed by some that the theory1 and largely the form1 of the modern successful aroplane was first suggested by an ,english inventor1 ,sir ,george ,cayley1 as early as #agif4 ,cayley argued that a flat plane or surface when driven through the air inclined slightly upward would lift a considerable weight4 ,he also suggested that a tail would help to steady the plane as well as steer it upward or downward4 ,his ideas of propelling the aroplane by screws driven by motors was also far in advance of his time1 but the engines then in existence were much too heavy for the purpose and he never built a model4 ,fifty years later1 when the steam engine had been highly developed1 these old plans were remembered and two engineers1 ,hensen and ,stringfellow1 actually built a flying machine on ,cayley's principles4 ,this early aroplane was of the monoplane form1 made of oiled silk stretched over a frame of bamboo4 ,a car to carry a steam engine1 and presumably the passengers1 was hung below this plane4 ,the motive power was supplied by two propellers at the rear4 ,the aroplane carried a fan-shaped tail with a rudder for steering it sideways1 placed beneath4 ,the model is said to have actually flown for a short distance1 but proved to be unstable4 ,from this time onward the experiments became more scientific and accurate4 ,reliable scientific data was accumulated which later enabled the aviators to build practical aroplanes4 ,a number of interesting experiments were made shortly afterward by a scientist named ,wenham to prove that the lifting powers of a carrying surface might be increased by arranging small surfaces in tiers one above another4 ,wenham had watched the birds to some purpose1 and decided that a single plane1 large enough to support a man would be too large to control1 but that a number of small surfaces would make the bird flight possible4 ,wenham built and patented a machine in #ahff4 ,he never flew but he collected a great deal of valuable information about the behavior of planes4 ,illustration3 ,,plate ,,xiv4 ,the ,under ,body of the ,monoplane ,shown1 ,plate ,,xiii4 ,the slow1 but on the whole1 encouraging movement toward the successful flying machine was given a serious set back in #ahgb by a book written by ,h4 ,von ,humboldt announcing the result of his experiments4 ,this well known scientist1 whose name carried great weight1 wrote that mechanical flight was impossible4 ,he based his idea on the discovery that as the body increased in size the work or power required to lift it increased more rapidly than the size of the body4 ,in other words1 a very large bird or flying machine could not contain muscles strong enough or machinery strong enough to enable it to fly4 ,he argued that no bird larger than the albatross1 for instance1 had ever lived1 therefore no flying machines could ever be more than toys4 ,the book was so discouraging that many aviators gave up their experiments and the science of aviation stood still4 ,it may be said to have been awakened1 however1 by the ,german scientist1 ,otto ,lilenthal1 whose book1 published in #ahhf1 at once attracted world wide attention4 ,it was this book1 incidentally1 which inspired the ,wright ,brothers to begin their experiments4 ,lilenthal was not only a great scientist1 but he worked on the principle that an ounce of actual experience was worth a ton of theory4 ,in aviation1 where the weight is all important1 this saving was naturally of the greatest importance4 ,lilenthal built gliders1 many of them1 and put to actual test the theories which others had merely talked and figured about4 ,finally he set up an engine on a glider but the machine turned over and he was instantly killed4 ,the scientific information he collected1 however1 proved of the highest value to those who later actually conquered the air4 ,lilenthal built a hill fifty feet in height and shaped like a cone with sides slanting at an angle of thirty degrees4 ,here he proved by actual tests that he might fly no matter which way the wind blew and that an arched surface1 driven against the wind1 would rise from the ground and support his weight4 ,a great deal of scientific information was collected and tabulated as well as the exact effect of the pressure of the air4 ,he also changed the shape of the gliding surfaces1 making them very long and narrow and driving them edgewise as in the first form of aroplane4 ,the aroplane took shape in his hands4 ,the success of these experiments encouraged aviators in many countries to imitate him1 and so great was the interest aroused that even his fatal accident in #ahif did not discourage them4 ,the successful flying machine was now actually in sight4 ,illustration3 ,,plate ,,xv4 ,a ,simple ,model which ,proves ,steady in ,flight4 ,for a time it was believed that ,hiram ,s4 ,maxim would be the first to construct a flying machine which would actually fly4 ,he had gone about the problem in a thoroughly scientific manner1 sparing neither time nor expense4 ,an elaborate apparatus was first constructed like a revolving derrick1 to test accurately the lifting powers of various aroplanes of various sizes and shapes flying at different angles1 as well as the propelling force of many kinds of screws4 ,the horizontal arm of this machine was thirty feet1 nine inches long1 so that it described a circle of #bjj feet in circumference4 ,the arm was driven by an engine at high speed4 ,the various aroplane forms to be tested were attached to the extreme end of this arm1 and driven by propellers of various shapes and sizes1 exactly as they would be in actual flight4 ,every part of the machine1 meanwhile1 was so adjusted that the readings of the speed of the aroplane1 its lifting power1 the exact force of the propeller1 in fact1 every detail1 could be measured and recorded with scientific accuracy4 ,this preliminary work proved to be of the highest value4 ,the test showed1 for instance1 just what size the propeller should be for different size planes1 and the exact pitch of the screw which would give the best results1 the proper angle of elevation for the front plane1 the resistance offered by various shaped planes1 and the exact amount of power required for planes of different sizes4 ,a delicate machine was also built to test the different kinds of fabrics used for covering the planes4 ,the fabric was stretched over a small steel frame1 mounted at a slight angle1 in a blast of air4 ,the tendency of the cloth to lift or drift was then accurately measured4 ,the material which gave the greatest amount of lift and the least drift was used4 ,a large aroplane was finally built in #ahic4 ,it weighed #gejj pounds1 measured #ajd feet in width1 and was driven by a #cfj horsepower engine4 ,compared with the clear cut1 ship-shape air-craft of to-day this early model appears crude and cumbersome4 ,the main plane was almost square in shape1 while stability planes extended out from the sides4 ,a series of four narrow planes1 one above another1 were carried below on either side4 ,the machinery for driving was carried far below the main plane4 ,the two large propellers were placed in the stern4 ,the aroplane was run along a double-tracked railroad #ahjj feet in length1 to gather sufficient momentum to cause it to rise4 ,almost any school-boy of to-day familiar with the aroplane models could have told at a glance that the machine could not rise4 ,when it was finally sent down the track at a good clip1 the front wheels did actually rise a trifle but it immediately came down with a bad smash4 ,not in the least discouraged1 ,maxim at once designed a new machine4 ,this measured fifty feet in width and forty feet in length in the middle1 but with the corners cut off1 so that it was sharpened both fore and aft4 ,the wings were made long and narrow1 extending out twenty-seven feet beyond the main plane1 and large fore and aft rudders were attached4 ,it was not even expected that the machine would fly4 ,all that was hoped for was that it would lift somewhat so that its upward tendency might be accurately measured4 ,the most successful 8flight0 of this model will seem a very tame affair indeed to the boys of to-day who are daily reading of the marvellous voyages in air across sea and land4 ,the 8airship0 was run over its track and the steam pressure run up to #cbi pounds per square inch4 ,the speed increased and the upward thrust began to be felt4 ,finally the front wheels of the machine actually lifted from the track4 ,the rear axle rose three or four feet above its normal position4 ,when it alighted1 the delighted aronauts found that the wheels of the machine had passed over the turf for a very short distance1 without making any marks1 showing that for a second or so the machine was actually off the earth4 ,it seems curious to us to-day that this 8flight0 should have been considered remarkable4 ,illustration3 ,,plate ,,xvi4 ,the ,propeller and ,shaft of the ,model ,shown1 ,plate ,,xv4 ,the experiments carried out by ,s4 ,p4 ,langley1 beginning in #ahhg and lasting for four years1 placed a great deal of valuable1 scientific data in the hands of the aviators4 ,thousands of tests were made with an apparatus similar to that used by ,maxim4 ,in one class of these experiments solid metal planes were attached to the end of the revolving arm in such a way that they were free to fall for a fixed distance4 ,when in rapid1 horizontal motion1 the metal seemed to part with its weight1 and the material1 though one thousand times heavier than the air1 was found to be actually supported by it4 ,it was proven1 for instance1 that one horse power would support over #bjj pounds weight of planes driven at a speed of fifty miles an hour4 ,all this preliminary work1 or nearly all1 we now see1 was necessary before a practical aroplane could be constructed4 ,the early aviators1 although they did not fly1 at least showed what not to do1 and several paid the price of their lives for this knowledge4 ,lilenthal had mapped out the aroplane in the rough1 and determined the general shape it must take4 ,the experiments of ,maxim and ,langley enabled the successful aviators to calculate the size of the machine necessary to carry them and the amount of power required to drive it4 ,,chapter ,,iii ,,the ,,wright ,,brothers' ,,own ,,story ,the ,wright ,brothers brought to their work a genius for invention and1 making free use of the results of former investigation and experiment1 finally succeeded in building a heavier than air machine which would actually fly4 ,the story of their experiments and final success1 which one may read in their own words1 forms one of the most fascinating chapters in the history of invention4 ,the ,wright ,brothers' first flying machine was a mere toy4 8,late in the autumn of #ahgh0 they tell the story1 8our father came into the house one evening with some object partially concealed in his hands1 and before we could see what it was1 he tossed it into the air4 ,instead of falling to the floor1 as we expected1 it flew across the room till it struck the ceiling1 where it fluttered for a while1 and finally sank to the floor4 ,it was a little toy known to scientists as a #8hlicoptre' but which we1 with sublime disregard for science1 dubbed a bat4 ,it was a light frame of cork and bamboo which formed two screws driven in opposite directions by rubber bands under torsion4 ,a toy so delicate lasted only a short time in the hands of small boys1 but its memory was abiding40 ,the interest of the brothers in aronautics was awakened4 8,we began building these hlicoptres ourselves10 their story goes on1 8making each one larger than that preceding4 ,but1 to our astonishment1 we found that the larger the #8bat1' the less it flew4 ,we did not know that a machine having only twice the linear dimensions of another would require eight times the power4 ,we finally became discouraged1 and returned to kite-flying1 a sport to which we had devoted so much attention that we were regarded as experts4 ,but as we became older1 we had to give up this fascinating sport as unbecoming to boys of our age40 ,illustration3 ,,plate ,,xvii4 ,an ,ingenious ,model which ,fails to ,fly4 ,the ,wrights did not begin their experiments until the summer of #ahif4 ,they first prepared themselves thoroughly by reading the literature on aronautics1 making themselves familiar with the results of all the experimental work of the aviators--,langley1 ,chanute1 ,mouillard1 and others4 ,the ,wrights soon decided that the first thing to be solved was to build aroplanes which would fly and that1 until this was solved1 it was foolish to waste time building delicate and costly machinery to operate them4 ,they took up the problems of the glider and sought by actual tests what many scientists had been theorizing about for years4 ,they soon discarded the various forms of gliders then used for experiments4 ,the tests which led up to adopting the now famous ,wright model1 the basis for all heavier than air machines to-day1 occupied very little time4 ,the story of this marvellous discovery which will rank with that of ,robert ,fulton or ,watt1 is best told in their own words1 which are here somewhat abbreviated4 8,the balancing of a flier may seem1 at first thought1 to be a very simple matter10 say the ,wrights1 8yet almost every experimenter had found in this the point he could not satisfactorily master4 ,many different methods were tried4 ,some experimenters place the center of gravity far below the wings in the belief that the wings would naturally seek to remain at the lowest point4 ,a more satisfactory system1 especially for lateral balance1 was that of arranging the wings in the shape of a broad ,v to form a dihedral angle1 with the center low and the wing-tips elevated4 ,in theory this was an automatic action1 but in practice it had two serious defects2 first1 it tended to keep the machine oscillating2 and1 second1 its usefulness was restricted to calm air4 ,notwithstanding the known limitations of this principle1 it had been embodied in almost every prominent flying-machine which had been built4 8,we reached the conclusion that such machines might be of interest from a scientific point of view1 but could be of no value in a practical way4 ,we1 therefore1 resolved to try a fundamentally different principle4 ,we would arrange the flyer so that it would not tend to right itself4 ,we would make it as inert as possible to the effects of change of direction or speed1 and thus reduce the effects of wind-gusts to a minimum4 ,we would do this in the fore-and-aft stability by giving the aroplanes a peculiar shape2 and in the lateral balance1 by arching the surfaces from tip to tip1 just the reverse of what our predecessors had done4 ,then by some suitable contrivance1 actuated by the operator1 forces should be brought into play to regulate the balance40 8,lilenthal and ,chanute had guided and balanced their machines by shifting the weight of the operator's body4 ,but this method seemed to us incapable of expansion to meet large conditions1 because the weight to be moved and the distance of possible motion were limited1 while the disturbing forces steadily increased1 both with wing area and wind velocity4 ,in order to meet the needs of large machines1 we wished to employ some system whereby the operator could vary at will the inclination of different parts of the wings1 and thus obtain from the wind forces to restore the balance which wind itself had disturbed4 ,this could easily be done by using wings capable of being warped1 and adjustable surfaces in the shape of rudders4 ,a happy device was discovered whereby the surfaces could be so warped that aroplanes could be presented on the right and left sides at different angles to the wind4 ,this1 with an adjustable horizontal front rudder1 formed the main features of our first glider40 ,illustration3 ,,plate ,,xviii4 ,a ,good ,model ,excepting that its ,vertical ,rudders ,are ,too ,large4 8,we began our first active experiments at the close of this period1 in ,october1 #aijj1 at ,kitty ,hawk1 ,north ,carolina4 ,our machine was designed to be flown as a kite1 with a man on board1 in winds of from fifteen to twenty miles an hour4 ,but1 upon trial1 it was found that much stronger winds were required to lift it4 ,suitable winds not being plentiful1 we found it necessary1 in order to test the new balancing system1 to fly the machine as a kite without a man on board1 operating the levers through cords from the ground4 ,this did not give the practice anticipated1 but it inspired confidence in the new system of balance40 8,the machine of #aija was built with the shape of surface used by ,lilenthal1 curved from front to rear1 with a slight curvature of of its cord4 ,but to make doubly sure that it would have sufficient lifting capacity when flown as a kite in fifteen or twenty mile winds1 we increased the area from #afe square feet1 used in #aijj1 to #cjh square feet1 a size much larger than ,lilenthal1 ,chanute1 or ,pilcher had deemed safe4 ,upon trial1 however1 the lifting capacity again fell short of calculation1 so that the idea of securing practice while flying as a kite1 had to be abandoned4 ,mr4 ,chanute1 who witnessed the experiments1 told us that the trouble was not due to poor construction of the machine4 ,we saw only one other explanation--that the tables of air pressure in general use were incorrect40 8,we then turned to gliding--coasting down hill in the air--as the only method of getting the desired practice in balancing the machine4 ,after a few minutes' practice we were able to make glides of #cjj feet1 and in a few days were safely operating in twenty-seven mile winds4 ,in these experiments we met with several unexpected phenomena4 ,we found that1 contrary to the teachings of the books1 the center of pressure on a curved surface traveled backward when the surface was inclined1 at small angles1 more and more edgewise to the wind4 ,we also discovered that in free flight1 when the wing on one side of the machine was presented to the wind at a greater angle than the one on the other side1 the wing with the greater angle descended1 and the machine turned in a direction just the reverse of what we were led to expect when flying the machine as a kite4 ,the larger angle gave more resistance to forward motion1 and reduced the speed of the wing on that side4 ,the decrease in speed more than counterbalanced the effect of the larger angle4 ,the addition of a fixed vertical vane in the rear increased the trouble1 and made the machine absolutely dangerous4 ,it was some time before a remedy was discovered4 ,this consisted of movable rudders working in conjunction with the twisting of the wings40 8,the experiments of #aija were far from encouraging4 ,we saw that the calculations upon which all flying-machines had been based were unreliable1 and that all were simply groping in the dark4 ,having set out with absolute faith in the existing scientific data1 we were driven to doubt one thing after another1 till finally1 after two years of experiment1 we cast it all aside1 and decided to rely entirely upon our own investigations4 ,truth and error were everywhere so intimately mixed as to be indistinguishable4 ,nevertheless1 the time expended in preliminary study of books was not misspent1 for they gave us a good general understanding of the subject1 and enabled us at the outset to avoid effort in many directions in which results would have been hopeless40 8,to work intelligently1 one needs to know the effects of a multitude of variations that would be incorporated in the surfaces of flying-machines4 ,the pressures on squares are different from those on rectangles1 circles1 triangles1 or ellipses2 arched surfaces differ from planes1 and vary among themselves according to the depth of curvature2 true arcs differ from parabolas1 and the latter differ among themselves2 thick surfaces differ from thin1 and surfaces thicker in one place than another vary in pressure when the positions of maximum thickness are different2 some surfaces are more efficient at one angle1 others at other angles4 ,the shape of the edge also makes a difference1 so that thousands of combinations are possible in so simple a thing as a wing40 ,illustration3 ,,plate ,,xix4 ,a ,simple ,cellular ,form4 8,we had taken aronautics merely as a sport4 ,we reluctantly entered upon the scientific side of it4 ,but we soon found the work so fascinating that we were drawn into it deeper and deeper4 ,two testing machines were built1 which we believed would avoid the errors to which the measurements of others had been subject1 after making preliminary measurements on a great number of different-shaped surfaces1 so varied in design as to bring out the underlying causes of difference noted in their pressure4 ,measurements were tabulated on nearly fifty of these at all angles from zero to #de degrees4 8,in ,september and ,october1 #aijb1 nearly one thousand flights were made1 several of which covered distances of over #fjj feet4 ,some1 made against a wind of thirty-six miles an hour1 gave proof of the effectiveness of the devices for control4 ,with this machine1 in the autumn of #aijc1 we made a number of flights in which we remained in the air for over a minute1 after soaring for a considerable time in one spot1 without any descent at all4 ,little wonder that our unscientific assistant should think the only thing needed to keep it indefinitely in the air would be a coat of feathers to make it light40 8,with accurate data for making calculations1 and a system of balance effective in winds as well as in calms1 we were now in a position1 we thought1 to build a successful power-flyer4 ,the first designs proved for a total weight of #fjj pounds1 including the operator and an eight horsepower motor4 ,but1 upon completion1 the motor gave more power than had been estimated1 and this allowed #aej pounds to be added for strengthening the wings and other parts4 8,it was not till several months had passed1 and every phase of the problem had been thrashed over and over1 that the various reactions began to untangle themselves4 ,when once a clear understanding had been obtained1 there was no difficulty in designing suitable propellers1 with proper diameter1 pitch1 and area of blade1 to meet the requirements of the flyer4 ,high efficiency in a screw propeller is not dependent upon any particular or peculiar shape1 and there is no such thing as a #8best' screw4 ,a propeller giving a high dynamic efficiency when used upon one machine1 may be almost worthless when used upon another4 ,the propeller should in every case be designed to meet the particular conditions of the machine to which it is to be applied4 ,our first propellers1 built entirely from calculation1 gave in useful work #ff per cent of the power expended4 ,this was about one third more than had been secured by ,maxim and ,langley40 8,the first flights with the power-machine were made on the #agth of ,december1 #aijc4 ,the first flight lasted only twelve seconds1 a flight very modest compared with that of birds1 but it was1 nevertheless1 the first in the history of the world in which a machine carrying a man had raised itself by its own power into the air in free flight1 had sailed forward on a level course without reduction of speed1 and had finally landed without being wrecked4 ,the second and third flights were a little longer1 and the fourth lasted fifty-nine seconds1 covering a distance of #hec feet over the ground against a twenty-mile wind40 8,after the last flight1 the machine was carried back to camp and set down in what was thought to be a safe place4 ,but a few minutes later1 when engaged in conversation about the flights1 a sudden gust of wind struck the machine1 and started to turn it over4 ,all made a rush to stop it1 but we were too late4 ,mr4 ,daniels1 a giant in stature and strength1 was lifted off his feet1 and falling inside1 between the surfaces1 was shaken about like a rattle in a box as the machine rolled over and over4 ,he finally fell out upon the sand with nothing worse than painful bruises1 but the damage to the machine caused a discontinuance of experiments4 ,illustration3 ,,plate ,,xx4 ,a ,cellular ,type with ,rudder and ,elevating ,plane4 8,in the spring of #aijd1 through the kindness of ,mr4 ,torrence ,huffman of ,dayton1 ,ohio1 we were permitted to erect a shed1 and to continue experiments1 on what is known as the ,huffman ,prairie1 at ,simms ,station1 eight miles east of ,dayton4 ,the new machine was heavier and stronger1 but similar to the one flown at ,kitty ,hawk4 ,when preparations had been completed1 a wind of three or four miles was blowing1--insufficient for starting on so short a track1--but since many had come a long way to see the machine in action an attempt was made4 ,to add to the other difficulty1 the engine refused to work properly4 ,the machine1 after running the length of the track1 slid off the end without rising in the air at all4 ,several of the newspaper men returned the next day1 but were again disappointed4 ,the engine performed badly1 and after a glide of only sixty feet1 the machine came to the ground4 ,further trial was postponed till the motor could be put in better running condition4 8,we had not been flying long in #aijd before we found that the problem of equilibrium had not as yet been entirely solved4 ,sometimes1 in making a circle1 the machine would turn over sidewise despite anything the operator could do1 although1 under the same conditions in ordinary flight1 it could have been righted in an instant4 ,in one flight1 in #aije1 while circling about a honey-locust tree at a height of about fifty feet1 the machine suddenly began to turn up on one wing1 and took a course toward the tree4 ,the operator1 not relishing the idea of landing in a thorn tree1 attempted to reach the ground4 ,the left wing1 however1 struck the tree at a height of ten or twelve feet from the ground1 and carried away several branches2 but the flight1 which had covered a distance of six miles1 was continued to the starting point4 8,the causes of these troubles--too technical for explanation here--were not entirely overcome till the end of ,september1 #aije4 ,the flights then rapidly increased in length1 till experiments were discontinued after the #eth of ,october4 8,a practical flyer having been finally realized1 we spent the years #aijf and #aijg in constructing new machines and in business negotiations4 ,it was not till ,may of this year 7#aijh7 that experiments were resumed at ,kill ,devil ,hill1 ,north ,carolina4 ,the recent flights were made to test the ability of our machines to meet the requirements of a contract with the ,united ,states ,government to furnish a flier capable of carrying two men and sufficient fuel supplies for a flight of #abe miles1 with a speed of forty miles an hour4 ,the machine used in these tests was the one with which the flights were made at ,simms ,station in #aije1 though several changes had been made to meet present requirements4 ,the operator assumed a sitting position1 instead of lying prone1 as in #aije1 and a seat was added for a passenger4 ,a larger motor was installed1 and radiators and gasolene reservoirs of larger capacity replaced those previously used40 ,illustration3 ,,plate ,,xxi4 ,a ,complicated ,model ,capable of ,long ,flights4 ,let us now take a short air journey with one of the ,wright ,brothers as pilot4 ,he describes the experience as follows1 8,let us fancy ourselves ready for the start4 ,the machine is placed on a single rail track facing the wind and is securely fastened with a cable4 ,the engine is put in motion1 and the propellers in the rear whirr4 ,you take your seat at the center of the machine beside the operator4 ,he slips the cable1 and you shoot forward4 ,an assistant who has been holding the machine in balance on the rail1 starts forward with you1 but before you have gone fifty feet the speed is too great for him1 and he lets go4 ,before reaching the end of the track the operator moves the front rudder1 and the machine lifts from the rail like a kite supported by the pressure of the air underneath4 ,the ground under you is at first a perfect blur1 but as you rise the objects become clearer4 ,at a height of one hundred feet you feel hardly any motion at all1 except for the wind which strikes your face4 ,if you did not take the precaution to fasten your hat before starting1 you have probably lost it by this time4 ,the operator moves a lever2 the right wing rises and the machine swings about to the left4 ,you make a very short turn1 yet you do not feel the sensation of being thrown from your seat1 so often experienced in automobile and railway travel4 ,you find yourself facing toward the point from which you started4 ,the objects on the ground seem to be moving at much higher speed1 though you perceive no change in the pressure of wind in your face4 ,you know then that you are traveling with the wind4 ,when you near the starting point1 the operator stops the motor while still high in the air4 ,the machine coasts down at an oblique angle to the ground1 and after sliding fifty or a hundred feet1 comes to rest4 ,although the machine often lands when traveling at a speed of a mile a minute1 you feel no shock whatever1 and cannot in fact1 tell the exact moment at which it first touched the ground4 ,the motor close beside you kept up an almost deafening roar during the whole flight1 yet in your excitement1 you did not notice it till it stopped40 ,on his return from ,le ,mans ,mr4 ,wilbur ,wright estimated that during a single year he had flown upwards of #cjjj miles4 ,with the memory of these marvellous flights in his mind he described his sensations to the present writer with enthusiasm4 8,flying is the greatest sport in the world10 says ,mr4 ,wilbur ,wright4 8,i can't describe the sensation1 ,i can only define it by comparison with more familiar experiences4 ,it is like sledding1 like motoring1 like sailing1 but with increased exhilaration and freedom4 8,an aroplane flight1 contrary to the general impression1 is far steadier than the familiar means of locomotion4 ,there is absolute freedom from the bouncing of the automobile1 the jar of a railroad train1 or the rolling and pitching sensations of the sea4 ,no matter how many springs or cushions may be added to the automobile1 for instance1 there will always be some motion4 ,on the other hand1 the seat of an aroplane is always steady4 ,the aroplane does not jolt over the invisible wind currents1 the ruts of the sky4 ,it cuts its way smoothly4 ,even suppose the plane to be gliding so 7indicating an angle of forty-five degrees71 the seat remains fixed4 ,there is1 of course1 no absolute parallel in surface travel4 ,and since there is no roll or pitch to the aroplane1 there is no air-sickness comparable to the familiar sea sickness40 ,,chapter ,,iv ,,aboard ,,the ,,wrights' ,,airship ,seen high aloft the ,wright aroplane appears so graceful and fragile that its actual dimensions come as a surprise4 ,in the upper air it seems no larger than a swallow1 but1 as it settles to earth1 the wings lengthen out to the width of an ordinary street4 ,there is some good reason for each stick and wire1 and for every twist and turn of the ,wrights' marvellous airship4 ,when one considers what wonderful feats this aircraft performs1 its form and mechanism seem extremely simple4 ,it is far less complicated than any locomotive or steamship1 and the action of its planes is far easier to explain than the sails of an ordinary seagoing ship4 ,when one has once gone over the fascinating little craft1 all other aroplanes1 which more or less resemble it1 may be readily understood4 ,illustration3 ,,plate ,,xxii4 ,an ,interesting ,form which ,flies ,backward or ,forward4 ,the ,wright machine was not only the first power airship to fly and carry a man aloft1 but for all its rivals1 it still rides the unstable air currents more steadily than any other4 ,the planes measure forty feet from tip to tip1 six and a half feet across1 and are spaced six feet apart4 ,the distance between the planes is very important and was only fixed after a number of experiments4 ,the area of the wings or supporting surfaces is #edj feet1 which is considerably more than in most airships4 ,the machine complete1 without any passenger or pilot1 weighs #hhj pounds1 although you would imagine it to be much less4 ,the two propellers measure eight feet in diameter1 and turn at the rate of #dej revolutions a minute4 ,equipped with a four cylinder engine of from #be to #cj horse power1 the airship has a speed of forty miles an hour1 which is often increased when traveling with the wind4 ,the seats for the pilot and the passenger are placed at the center at the front of the lower plane1 so that their feet hang over the front or entering edge4 ,the passenger sits very comfortably throughout the flight4 ,there is a back to lean against1 a brace for the feet1 while the struts between the planes give every opportunity to hold on4 ,in some of the models these seats are even upholstered in gray to harmonize with the silver or aluminium paint of the machine4 ,a second and smaller biplane1 which serves both as rudder and lifting plane1 extends about ten feet in front of the main planes4 ,these two planes1 which have a combined area of eighty square feet1 may be inclined upward or downward by touching a lever at the pilot's seat4 ,the motor1 radiator and petrol or fuel tank are placed on the lower plane in the center of the machine so that they balance the weight of the pilot and the passenger4 ,the weight of the lifting planes and rudders rests on the main planes or lower deck4 ,illustration3 ,,plate ,,xxiii4 ,a ,well ,built ,model ,badly ,proportioned4 ,the most interesting feature of the ,wrights' airship is1 of course1 the method for flexing the tips of the wings or planes to imitate the flight of the birds4 ,the ends of the large planes are made slightly flexible1 and may be turned up or down by moving a lever placed convenient to the pilot's hand4 ,both planes are flexed1 or turned up or down1 at the same time the vertical rudder moves1 so that1 when the aroplane turns to right or left1 the wings give the machine the proper balance4 ,if it were not for this arrangement1 the ends of the planes in turning would tend to rise1 since they travel the faster1 and the machine would be in danger of upsetting4 ,the ends of the planes may also be flexed separately when the machine is in straight flight1 whenever it becomes necessary to balance it against a dangerous air current or a gust of wind4 ,the pilot1 it will be seen1 has every point of the great machine1 as it were1 at his finger ends4 ,the marvellous power placed in the hands of the pilot of one of these models makes him almost equal of the birds soaring about him4 ,let us suppose an accident to occur4 ,even should the engine stop1 the skillful pilot is still master of the situation4 ,he can actually coast down to the ground on the air with comparative safety4 ,mr4 ,orville ,wright has soared up #cjjj feet and1 after stopping his propeller1 slid down on nothing at all1 at the rate of more than twenty miles an hour1 by the force of gravity alone4 ,the ,wright method of alighting is also borrowed from the birds4 ,watch any bird alight on a twig1 and you will see that it always settles on the top of the twig1 which is pressed straight down by its weight1 and never sideways4 ,as the ,wrights come down1 they approach to within a few feet of the earth1 but1 without touching they swoop up again1 and finally settle down from a height of only a few feet4 ,considering the weight of their machine1 they actually come down as lightly as a bird4 ,while traveling at a speed of forty miles an hour they will skid along the ground or come to rest within five or six feet1 so quietly that a passenger cannot tell when he lands4 ,no part of the aroplane calls for more clever workmanship than the wings or planes4 ,they must be so thin and light that they will ride the air like the wings of a bird1 and yet strong enough to support the weight of hundreds of pounds of machinery and of passengers4 ,in the ,wright model1 the planes are made entirely of wood1 but so ingeniously braced that they are perfectly rigid4 ,the building of such a wing is especially difficult1 since it must be curved with scientific accuracy4 ,in the ,wright model machines1 as in all aroplanes1 the curve is upward1 with the highest point of the arch near the front or entering edge4 ,both sides of the frame are completely covered so that they may offer the least possible amount of resistance4 ,there is not a ridge1 scarcely a seam1 to catch the air4 ,a stout canvas is used for covering4 ,the ingenuity of these clever workmen led them to lay on the cloth with the thread running diagonally1 at an angle of forty-five degrees4 ,this plan serves to hold the frame more closely together and keeps the cloth from bagging or wrinkling4 ,at the first glance1 the ,wright machine appears to be made entirely of aluminium4 ,seen high aloft in the sunlight1 it appears like some delicate jewel4 ,the effect is due to the paint4 ,the entire framework of the machine is made of spruce pine except the curved part of the wings1 or entering edge1 which is of ash4 ,the propellers are driven by chains1 connected with the motor1 which run in steel tubes1 thus doing away with the danger of fouling by passengers or loose objects4 ,the ignition system is operated by a high tension ,eisenmann magneto machine4 ,the petrol used for fuel is carried in a tank placed above the engines and is supplied by gravity4 ,the two wings are connected by a series of distance rods and wire cross-stays1 which keep the entire front1 or entering edge1 and central part of the model1 perfectly rigid4 ,illustration3 ,,plate ,,xxiv4 ,a ,wright ,model ,ready for ,flight4 ,although nearly all the aroplanes1 nowadays1 are mounted on ordinary bicycle wheels1 the ,wrights prefer a simple system of skids1 not unlike the runners of a sleigh4 ,one of the great advantages of the skids is the fact that they take up the shock on landing more completely than wheels and protect the machine from many a hard bump4 ,the airship rests on a small frame mounted on two wheels1 placed tandem1 and is balanced on a small trolley which runs along a rail about twenty-five feet in length4 ,it is started by the pull of a rope attached to a #aejj pound weight1 which drops from a derrick fifteen feet in height4 ,when everything is ready1 the temporary wheels are taken away1 the rope is attached1 and finally the weight released4 ,the machine glides swiftly down the track1 and when the necessary speed has been reached1 the pilot raises his elevating planes1 a trifle1 and the ship glides gracefully upward and onward4 ,,chapter ,v ,,other ,,aeroplanes ,,appear ,in the summer of #aijd the boys of ,paris were greatly interested in watching a curious1 giant kite in flight over the ,river ,seine4 ,the string of this kite was drawn by a fast motor boat1 which darted along1 while the kite rose high in the air4 ,its inventor tinkered with it1 and changed its wings about until it finally flew like no other kite ever seen in ,france4 ,all this was by no means mere play1 however1 for many scientists watched the kite as it soared about and a great deal of valuable information about the behavior of kites of this shape was learned4 ,the man with the kite1 who soon became famous in the world of aviation1 was named ,voisin4 ,the aroplane1 which he afterwards built1 modeled on this kite1 was flown in many remarkable flights by ,henry ,farman1 ,delagrange1 ,paulhan1 and others4 ,like the ,wright airship1 ,voisin's is a biplane or double plane model4 ,although at first glance1 the ,voisin and ,wright aroplanes may seem very much alike1 as we look more closely1 we will find many points of contrast4 ,the ,voisin model has a large tail-piece1 consisting of two vertical planes1 which project far behind4 ,these planes are believed to make its flight very steady4 ,a single vertical rudder is placed between the two rear edges of this plane4 ,the rudders are turned by horizontal1 sliding bars attached to the wheels1 directly before the pilot's seat1 like an automobile4 ,the horizontal rudder in front1 which corresponds to the ,wrights' double lifting plane1 is single and is placed lower down than in the ,wright model4 ,the steadiness of the ,voisin aroplane in flight is gained without flexing the planes4 ,a series of four vertical planes connect the upper and lower wings which give the machine much the appearance of a box kite4 ,these walls are arranged so that the space enclosed at either end is almost square4 ,it is believed that the arrangement of these walls keeps the air from sliding off the under surface of the horizontal planes1 and thus greater lifting power is obtained4 ,it is claimed that the model has much greater longitudinal stability than the ,wrights' machine4 ,in other words1 the long tail piece prevents the machine from tipping or pitching when the wind gusts come unevenly4 ,the box-like or cellular form1 it is believed also1 adds to its stability4 ,the model holds the record for flying at the lowest speed--#bb4h miles an hour4 ,on the other hand1 the ,voisin model cannot1 with any degree of safety1 coast down on the air from great altitudes1 like the ,wright model4 ,the method of starting the ,voisin airship is entirely different from the ,wrights'4 ,the machine is mounted on two wheels1 attached to the girder body with an arrangement of springs to take up the shock on landing4 ,to launch the aroplane1 the propellers are started1 and the machine rushes forward on its wheels until it has developed sufficient speed to send it up4 ,it may thus rise from an ordinarily level ground1 and does not require the apparatus used by the ,wrights4 ,the pilot and passenger sit in much the same position as in the ,wright aroplane4 ,the ,voisin model weighs #cjj pounds more than the ,wrights' or #aeij pounds4 ,it has a supporting surface of #ece square feet1 and a speed1 under favorable conditions1 of #ch miles an hour4 ,another point of difference from the ,wright model is the propeller1 which is single and measures seven feet six inches in diameter4 ,the motor1 an eight cylinder ,antoinette1 usually gives fifty horse power at #aajj revolutions per minute4 ,the ,wright ,brothers1 by the way1 make their own motors1 which are considered inferior to the ,french motors4 ,the smallest and swiftest of all the aroplanes is the ,curtiss-,herring model1 which was invented by two ,americans whose names it bears4 ,its general form suggests the ,wrights' machine4 ,the span of the large planes is only #bi feet or under1 the depth but four feet six inches1 and the spacing four feet six inches4 ,it has a total wing surface of but #beh square feet4 ,the weight1 not including the pilot1 is only about #dej pounds4 ,when seen beside the aroplane of ordinary size1 the little craft looks like a very large toy model4 ,it has the appearance of a smart little racer1 however1 and its maximum speed is over #ej miles an hour4 ,everything has been sacrificed in the ,curtiss-,herring model for the sake of compactness4 ,the forward rudder1 which seems small even for such a craft1 consists of two planes1 one above the other1 whose combined area is only twenty-four square feet4 ,unlike the ,wright or ,voisin models1 this forward rudder carries a vertical plane which makes for stability4 ,there is no tail as in the ,voisin model1 and the rear1 vertical rudder consists of a horizontal plane six feet wide and two feet1 three inches deep and a vertical rudder below it1 two feet deep and three feet four inches wide4 ,the front and rear planes extend out from the main frame about the same distance4 ,the main stability planes1 curiously enough1 are placed inside the frame4 ,there are two of these1 one at either end of the main plane4 ,an ingenious method has been followed to control the various planes4 ,the pilot sits facing a wheel1 like that of an automobile1 which is so rigged that by simply pushing it from him or pulling it back1 he may lift or decline the front planes4 ,by turning this wheel he operates the rudder in the rear1 exactly as you would steer an automobile or a boat4 ,the balancing mechanism in turn is connected with a frame which fits about the pilot's shoulders like a high-backed chair and is operated by merely leaning to one side or the other4 ,this has the same effect as warping the main planes4 ,the control of the machine becomes largely automatic4 ,if the pilot feels that his aroplane is tilting over at one end or the other1 he merely leans to one side or the other1 and1 without taking his hands from the wheel before him1 has the machine under perfect control4 ,even the motor is controlled by pedals placed under the pilot's feet4 ,this little racer is mounted on three wheels1 one well forward and two in the rear about half way between the main planes and the horizontal rudder4 ,an original feature of this model is a foot brake which1 connecting with the forward wheel1 helps to slow down the machine on landing1 just as you close the brake of an automobile4 ,there is only one rudder measuring six feet in diameter1 which is unusually large considering the size of the model4 ,the engine is mounted at the center of the space between the two main planes1 and the propeller1 which is kept on a line with it1 is therefore considerably higher than in most aroplanes4 ,the lower plane comes very near the ground4 ,it is only raised by about the height of the bicycle wheels4 ,it is thought by some that this arrangement of the engine blankets the propeller1 while others argue that the suction produced in this way increases the thrust of the propeller4 ,the machine is built of ,oregon spruce1 the wings are covered with oiled rubber silk1 and the entire mechanism is beautifully finished in every detail4 ,illustration3 ,,plate ,,xxv4 ,another ,view of the ,wright ,model4 ,the ingenuity of the designers of aroplanes is astonishing4 ,with so many aroplanes in the field1 or rather in the sky1 it is surprising that they are not more alike4 ,the ,farman biplane1 for instance1 follows the same general proportion as the ,wright machine1 but there the similarity ends4 ,to secure equilibrium in this model1 four small planes are used1 hinged at the back of the two main planes1 and these1 it has been found1 take the place of the flexing device used by the ,wrights4 ,the two swinging planes on the lower wing are controlled by wires1 while the upper two swing free4 ,a single lever controls the two lower planes and the horizontal rudder4 ,farman has placed his rear stability planes unusually far behind the main frame4 ,they consist of two fixed horizontal planes1 one above the other1 with a vertical rudder placed in the space between them4 ,the front horizontal rudder for vertical steering1 is a single plane1 mounted close to the entering edge4 ,the vertical rudder is worked by a foot pedal4 ,the machine is driven by one large wooden propeller1 eight feet six inches in diameter1 at a speed of #acjj revolutions per minute1 which1 it will be noticed1 is unusually high4 ,the ,farman biplane is one of the heaviest yet constructed1 weighing about #ajjj pounds without the pilot4 ,an original plan has also been found for mounting the machine4 ,the aroplane rests upon a combination of skids and wheels4 ,there are two sets of wheels under the front edge of the plane1 while the two skids are placed between the wheels of each pair4 ,the motor is four cylinder1 fifty horse power type1 and drives the machine at the rate of forty miles an hour4 ,the largest1 and by far the heaviest aroplane is the ,cody biplane built by an ,american inventor who lives in ,england4 ,it weighs nearly one ton1 or more than #ahjj pounds1 to be exact1 and measures fifty-two feet across4 ,the machine is balanced somewhat after the manner of the ,curtiss-,herring model1 by two horizontal planes placed at the extremities of the main planes and midway between the rear corners4 ,the two main planes are seven feet six inches wide and are placed nine feet apart1 which is considerably farther than in any other successful model4 ,the upper plane is slightly curved toward the ends4 ,the machine carries two large horizontal planes for vertical steering1 sixteen feet before the entering edge of the main wings4 ,these planes1 placed side by side1 have a combined area of #aej square feet and naturally exert a considerable lifting force4 ,a small vertical rudder for horizontal steering is carried above and between these front planes4 ,an unusually large rudder is placed well behind the machine1 consisting of a vertical plane with an area of forty square feet4 ,all the rudders are operated by a wheel in front of the pilot's seat4 ,in the ,cody aroplane the horizontal rudders are moved by pushing or pulling the wheel1 while by moving it sideways the two balancing planes1 which control the equilibrium1 are moved up and down4 ,the most original feature of the ,cody machine is the position of the propellers4 ,they are carried in the space between the two main planes forward of the center4 ,it would seem that they must draw the air from the upper planes and affect their lifting quality4 ,the machine is mounted on three wheels1 two beneath the front edge of the main plane1 and the other slightly forward1 which is an unusual distribution4 ,the ,cody biplane1 with #ggj feet of wing surface1 lifts more than #ahjj pounds4 ,illustration3 ,,plate ,,xxvi4 ,an ,ingenious ,model which ,rises ,quickly4 ,it is all a matter of guess work1 of course1 whether the monoplane1 biplane1 or some entirely new form of aroplane will come into general use4 ,every model has its enthusiastic friends4 ,the biplane1 at present1 has greater stability than the monoplane1 and carries greater weights for longer distances4 ,the development of the flying machine is so rapid however that in five or ten years the successful aroplane models of to-day may appear as crude as do the clumsy1 lumbering old horseless carriages of five or ten years ago4 ,,chapter ,,vi ,,successful ,,monoplanes ,while the biplane borrows the general principles of flight from the birds1 the monoplane carries us a step further and almost exactly reproduces their form and movement4 ,seen high aloft1 with wings outspread1 the monoplanes look like great eagles as1 gracefully1 but very noisily1 they rise and fall in long1 sweeping curves4 ,the monoplane being a much lighter machine and less complicated is therefore cheaper to build than any multiplane model4 ,several of the successful models ride the air very steadily and have proven themselves capable of making long and difficult air journeys4 ,illustration3 ,,plate ,,xxvii4 ,an ,aroplane with ,paper ,wings4 ,some aviators believe that the monoplane type1 highly developed1 to be sure1 will some day be adopted for great commercial airships4 ,even in its present form1 these mechanical birds look very shipshape4 ,the pilot can find a more comfortable seat among these wings than in the biplane forms1 and it takes little imagination to picture these airships1 greatly enlarged1 carrying comfortable cabins filled with air voyagers4 ,the most successful model aroplanes1 by the way1 are of the monoplane form4 ,the first monoplane to make an extended flight was the ,bleriot4 ,its inventor had worked with ,voisin in the experiments above the ,river ,seine at ,paris in #aijf1 and beginning with short flights of only a few yards worked his way step by step4 ,the machine in which he crossed the ,english ,channel in #aiji1 and made several remarkable cross country flights1 was his eleventh model4 ,bleriot's most successful model consists of only two wings curved upward1 mounted on a long motor base which measures twenty-six and one half feet in length4 ,the body of the monoplane1 which is made of ash and poplar1 tapers to a point in the rear and is partially covered with 8,continental fabric10 similar to balloons4 ,the front or main wing is twenty-five and a half feet in width with a surface of #aei square feet4 ,the rear plane measures only six feet in width1 and three feet in depth and is equipped with moveable tips or horizontal rudders two feet square at either side4 ,the vertical rudder for steering to right or left1 is carried behind the frame4 ,the planes are braced by a series of stay wires running in all directions4 ,unlike the biplane1 the motor of the monoplane is placed in front of the wings4 ,the blades of the propeller1 which are unusually broad1 measure less than seven feet from tip to tip4 ,the pilot's seat is inside the motor frame near the rear edge of the main wing1 and with its high back and sides appears to be a comfortable place to sit4 ,it has the disadvantage1 however1 of being directly behind the motor1 so that a draft of air strikes the driver in the face4 ,the pilot keeps his machine on an even keel by flexing the tips of the planes1 much the same as in the ,wright model4 ,the tips of the main plane and of the two horizontal rudders are connected with a single lever1 which gives the pilot perfect control of them4 ,the horizontal rudders may be turned to steer the aroplane up or down in the same way4 ,the vertical rudder for turning the aroplane from right to left1 is operated by a foot lever4 ,the ,bleriot monoplane weighs about #ejj pounds1 so that it carries about four pounds for every square foot of wing surface1 or thirteen pounds per square foot1 which is from two to four times greater than is the case of any biplane4 ,the machine is mounted on three wheels1 two at the front and one near the rear1 just forward of the rudders4 ,it has a speed of nearly forty miles an hour4 ,all the present monoplane models follow the same general plan of placing their propellers and larger planes in front and their horizontal rudder for vertical steering in the rear4 ,the idea is gaining ground1 however1 that it would be better if this arrangement was reversed1 and they flew with what is now the tail in front4 ,the theory of this arrangement is that if the edge of the lifting planes is presented to the air1 they would answer the helm much better1 as has been proven in the biplane forms4 ,the experiment of reversing the monoplane forms has been tried in model aroplanes with great success4 ,the heaviest and largest of the monoplanes at present is the ,antoinette model1 which is the invention of ,m4 ,levasseur4 ,it looks like a great dragon fly1 and has proven itself very steady in flight4 ,the main wings1 measuring forty-two feet in width seem to be arched unusually high from front to rear1 and taper rather sharply at the ends4 ,their total lifting surface is a trifle over #cjj feet4 ,in some of the ,antoinette models the wings are set in the form of a broad1 dihedral angle4 ,the monoplane is driven from a seat in the body of the frame as the ,bleriot model1 but moved slightly farther back4 ,the rear horizontal rudder is controlled by a large wheel at the left of the pilot's seat1 while a corresponding wheel on the right controls the small hinged wings at the outer edge of the main plane4 ,the pilot turns his airship from right to left by merely pressing two foot pedals connected with the vertical rudder in the rear4 ,in the later models1 the dihedral angle has been abandoned and the front planes set horizontally4 ,illustration3 ,a ,very ,simple ,monoplane for ,beginners4 ,the most novel feature of the ,antoinette model is the form and control of the rear rudders and stability planes4 ,the model carries two vertical rudders for turning the craft to the right or left1 and a large horizontal rudder for vertical steering1 extending far out behind at the end of the main body4 ,all of these rudders are triangular in shape1 tapering to a point in the rear4 ,the ,antoinette has proved1 it is believed1 that the corners of square rudders may be removed1 without affecting their guiding qualities1 thus saving considerable surface and weight4 ,it would seem1 on general principles1 that just the reverse would be the case4 ,the builder of model aroplanes may take a leaf from the log of this airship4 ,the ,antoinette stability planes are placed just forward of the rudders1 and are triangular in shape1 but with somewhat narrow ends pointing toward the front4 ,two of these planes are carried horizontally and one vertically1 the vertical planes being above the horizontals4 ,the chief fault of this model is that the rear horizontal stability plane1 being perfectly flat1 exerts little lifting power4 ,the method of warping the tips of the planes1 the same as in the ,wright aroplane1 works well with this model1 and the flights1 are as a rule1 remarkable steady4 ,the machine lands on wooden skids1 carried well forward1 connected with the frame by flexible joints4 ,it is supported in the rear by two wheels under the center of the planes4 ,the ,santos ,dumont monoplane is1 so far1 the smallest and lightest monoplane to make a successful flight4 ,it is the aronautical runabout1 and1 although it has made no very extended air journeys1 it has introduced several interesting features4 ,its owner has flown several miles across country in his little craft1 housed it in an ordinary stable while making a call1 and then1 starting from the front lawn1 flown home again without assistance of any kind4 ,his machine may be counted upon to fly at the rate of about thirty-seven miles an hour4 ,it weighs only #bde pounds without the pilot4 ,the main plane is set at an angle so that1 seen from the front1 the wings rise from the center1 but later bend down toward the tips4 ,the front or entering edge is also elevated to an unusually high degree1 giving it the appearance of a rather flat umbrella4 ,the pilot sits underneath this front plane just below the center4 ,the stability of this plane is maintained by fixing the ends in the usual manner4 ,the wires connecting with the ends of the planes1 are carried to a lever which is attached to the pilot's back4 ,the pilot1 therefore1 without using his hands1 but merely by swaying his body from side to side1 can warp the planes and bring his craft to an even keel4 ,the ,santos ,dumont monoplane carries no regular stability plane at the rear1 but depends for its support and guidance upon a small vertical and horizontal rudder at the end of its very short frame4 ,these two rudders bisect one another1 or in other words1 half of the vertical rudder is above and half below the horizontal rudder1 while half of the horizontal rudder is on one side and half on the other of the vertical rudder4 ,they are attached to a single rigid framework1 so that both move as a whole by means of a universal joint4 ,the rudders1 used for ascending and descending1 are operated by a lever1 while the rudders used for horizontal steering are controlled by a wheel4 ,illustration3 ,otto ,lilienthal about to ,take ,flight4 ,the aroplane is mounted on two wheels1 placed at the front of the frame and a vertical strut at the rear1 thus reversing the arrangement of the ,antoinette4 ,this adjustment works well in practice1 and the ,santos ,dumont holds the record for rising from the ground in the shortest distance4 ,it has risen in six and a quarter seconds after traveling only #bcj feet4 ,the area of its wings is only #aaj square feet and its propeller consisting of double wooden blades measures only six feet three inches in diameter4 ,it carries a #cj ,h4 ,p4 motor4 ,the ,r4 ,e4 ,p4 monoplane1 the name being formed by the initials of its inventor1 ,robert ,esnault-,pelterie1 is an experiment along new lines4 ,its inventor believes that the wires and struts of the monoplane in vibrating1 offer considerable resistance to the air and seriously retard its forward movement4 ,his monoplane has1 therefore1 been constructed practically without stays1 wires1 or rods4 ,the monoplane is graceful in form1 light and compact1 although somewhat expensive to build4 ,the main frame of the airship is made of steel girders with a broad surface and tapering to a sharp edge at the bottom4 ,it is covered completely with cloth1 thus forming a vertical stability plane of considerable area4 ,the motor and propeller are carried at the front of the frame1 while the pilot's seat is fixed inside the frame1 just back of the machinery4 ,the main planes have a span of thirty-five feet six inches4 ,they extend from either side of the frame1 and taper slightly toward their outer edges4 ,two large rudders are carried at the rear of the frame4 ,the vertical rudder for horizontal steering is attached to an extension of the main frame and the horizontal rudder projects from the end at a higher level4 ,a fixed vertical stability plane or fin extends along the main frame back of the pilot's seat4 ,the warping of the plane and the control of both rudders is accomplished by levers placed convenient to the pilot's hand4 ,the ,r4 ,e4 ,p4 model1 alone among the aroplanes1 is equipped with a four blade propeller4 ,it measures six feet six inches in diameter1 and is driven at the speed of #adjj revolutions per minute4 ,the speed of the craft is remarkable since it has flown for short distances at the rate of forty-seven miles an hour4 ,its weight1 #ghj pounds1 is not unusual4 ,an entirely new idea has been introduced in mounting this model4 ,it rests upon only two wheels1 one at the front1 the other at the end of the central frame4 ,wheels are also attached to the outer edges of the main plane4 ,when at rest1 the model tilts over to one side or the other and rests on one of these wheels4 ,once the motor has been started1 the machine quickly rights itself1 as the speed increases1 and runs along on two wheels4 ,,chapter ,,vii ,,aerial ,,warfare ,the boys who turn these pages may some day read of arial battles fought high above the earth1 and some may even take part in them4 ,air-ships are even now included in the navies of nineteen nations4 ,there is great difference of opinion among experts whether the balloon or aroplane will prove the better fighting machine1 but1 meanwhile1 aronautical corps and regiments are being recruited1 formidable navies of air-ships are being laid down1 and special guns are being built to battle against them4 ,illustration3 ,a ,machine for ,testing the ,lifting ,power of ,aroplanes4 ,in this machine power is transmitted from the horizontal main shaft and upward through the vertical steel spindle and through the two members of the long arm4 ,a is a scale showing miles per hour and ,b a scale divided into feet per minute2 ,c1 ,dynamometer for recording the push of screw2 ,d1 ,dynamometer showing the lift of the aeroplane4 ,the ordinary balloon has played a much more important part in actual warfare than most people realize4 ,a balloon corps was organized in ,france as early as #agid1 when balloons were built for each of the ,republican armies4 ,one of these balloons1 measuring thirty feet in diameter1 was sent up near ,mayence1 to gain a view of the ,austrian army4 ,the balloon was held captive by two ropes1 and an officer in the car wrote his observations1 weighted the letters1 and dropped them overboard4 ,the ,austrians were furious at this spying1 and opened fire1 but the ropes were lengthened and the balloon rose to a height of #acjj feet1 where it was out of range4 ,several years later balloons were again used in battles by the ,french against the ,austrians1 who were so angry with the new machine that they declared that any balloonist captured would be shot4 ,for a long time afterward1 however1 this method of warfare was neglected1 and even ,napoleon could not see its value1 and closed the aronautical school and disbanded the corps4 ,the use of the balloon was revived in ,america during the ,civil ,war1 and proved to be so valuable that no great war has since been fought without it4 ,during the attack on ,richmond1 a number of balloons were sent up daily by the ,federal ,army to overlook the besieged city4 ,from a point eight miles away1 valuable information was gained as to the position of the troops and the earthworks4 ,a telegraph apparatus was taken up and messages were sent directly from the clouds1 almost over ,richmond to ,washington4 ,in the ,spanish-,american ,war in #ahih1 the balloon was again called into use4 ,one ascent was made before ,santiago1 ,cuba1 and the position of the various ,spanish forces were observed and reported4 ,another was sent up at ,el ,paso1 less than #bjjj feet from the ,spanish trenches1 and the position of the ,spanish troops on ,san ,juan ,hill was discovered4 ,the balloon was finally brought down by the ,spanish guns4 ,during the siege of ,paris in #ahgj1 balloons were used successfully to escape from the city4 ,some sixty-six of them1 carrying #afh passengers1 succeeded in passing over the ,german armies4 ,the ,french army has also made good use of the balloon in the wars in ,madagascar1 and several ,english balloon corps were engaged with the ,british army during the ,boer ,war4 ,for ordinary military work1 balloons of three sizes are used1 a large balloon for forts1 the regular war balloon1 and an auxiliary for field work4 ,the large balloon holds #cd1ejj cubic feet of gas and is only used above fortifications4 ,the regular field balloon is thirty-three feet in diameter1 and holds #ai1jjj cubic feet of gas4 ,it is designed to carry two passengers to a height of #afej feet4 ,the auxiliary balloon is considerably smaller1 holding only #ibjj cubic feet of gas1 and carrying but one passenger4 ,it is much easier to handle on long marches1 and1 of course1 may be filled and sent aloft in much less time4 ,the balloons are usually filled from cylinders1 which may be hurried across country in carts or automobiles4 ,there is1 besides1 a regular field gas generator1 readily packed up and carried about1 which will fill an ordinary balloon in from fifteen to twenty minutes4 ,to resist arial attacks1 a special armored automobile has been adopted by some ,european armies1 carrying a gun which may be aimed upward and at any angle4 ,despite its weight1 the automobile will travel at the rate of forty miles an hour4 ,the recent developments of the dirigible war balloon has rendered the free balloon practically obsolete1 and it is unlikely that it will ever again be used in actual warfare4 ,the ,united ,states has been the first country to adopt the aroplane as a weapon of warfare4 ,after the successful flights of the ,wright ,brothers1 the ,war ,department purchased one of their aroplanes1 and several officers were instructed in driving it4 ,before being accepted1 the ,wrights were required to make a flight of ten miles over a rough1 mountainous country near ,washington1 and return without alighting4 ,the test1 which was highly successful1 was witnessed by ,president ,taft and many representatives of the ,government4 ,in the event of war1 the ,united ,states ,government could quickly mobilize a formidable fleet of aroplanes1 and man them with experienced aviators4 ,illustration3 ,the ,machine on the ,rails1 as it appeared in #ahic4 ,illustration3 ,maxim's ,first ,aroplane4 ,the value of aroplanes in warfare has been widely discussed by military experts4 ,there was1 at first1 a general impression that such flights were much too uncertain to be of practical value4 ,the marvellous development of the aroplane1 and its remarkable flights over land and sea1 have served to silence much of this criticism4 ,although an over-sea invasion by a fleet of air-ships would seem to be a danger of the very distant future1 the ,united ,states ,government is already preparing to meet the situation4 ,a remarkable series of tests have been made at the ,government ,proving ,grounds at ,sandy ,hook1 by firing at free balloons as they sailed past the fort4 ,the balloons were sent away at various altitudes1 in some cases at a considerable distance from the guns1 and again directly above them4 ,the difficulty in hitting such targets was found to be very great4 ,the air craft moves so quickly that it is almost impossible to bring a gun of the ordinary mounting into position4 ,although the results of the test were closely guarded1 it is known that the ,government was not satisfied with the defense of ,new ,york ,harbor1 in the event of an arial invasion1 and special guns are being designed to repel such an attack4 ,the military authorities look very far into the future in their preparations4 ,one of the most interesting of these problems is that of protecting our seacoast1 should a fleet of arial warships be sent against us4 ,one of the plans suggested is to raise a series of captive balloons at regular intervals along the shore4 ,it has been thought that some of these might be held near the earth1 while others are allowed to ascend to a great altitude4 ,the lookout in these signal stations could sight the approach of an hostile fleet of air-ships at a great distance1 and by means of wireless apparatus warn the country of approaching danger4 ,many military experts1 who have watched the flights of aroplanes1 have decided that the little craft would also prove an extremely difficult object for the enemy to bring down4 ,since they travel at upwards of a mile a minute1 ordinary guns1 as they are now mounted1 could not hope to hit them except by a lucky shot4 ,it would be like hunting wild geese with a cannon4 ,at a height of several thousand feet1 which they can readily attain1 an aroplane might defy the most formidable batteries in the world4 ,should a fleet of these little craft be sent against an enemy1 many of them would be sure to survive an attack1 even if a few should be lost4 ,it does not seem probable that the aroplane will carry aloft a cannon large enough to do any damage4 ,but they can drop high explosives1 with astonishing accuracy1 and would do important scout work4 ,at the present cost of construction1 a fleet of one hundred aroplanes might be built and put in commission in the field or sky1 for what a single great battleship would cost4 ,it has been shown1 moreover1 that a man can learn to operate an aroplane in less time than it takes to learn to ride a bicycle4 ,the ,wrights instructed ,lieutenant ,lahm to drive one of their machines in about two hours of actual flight4 ,the war aroplanes would call for great bravery and daring1 but who can doubt that men would be found to serve their country1 if need be1 by facing this appalling danger4 ,in military language1 the modern airships fall into three classes1 dreadnaughts1 cruisers and scouts4 ,the dreadnaughts of the air are the largest dirigible balloons1 such as ,zeppelin flies4 ,they will probably be used in arial warfare in the first line of battle1 and for over-sea work4 ,the cruisers comprise the dirigibles1 such as have been brought to great perfection in ,france4 ,these faster air-ships will rise higher than the dreadnaughts1 and will probably be used for guarding and scout work4 ,the aroplanes come under the head of scouts1 and will be used for dispatch work1 and for attacking dirigibles4 ,illustration3 ,first ,flight of the ,wright ,brothers' ,first ,motor ,machine4 ,this picture shows the machine just after lifting from the track1 flying against a wind of twenty-four miles an hour4 ,their speed and effective radius of travel place the air-ship in the first rank among the engines of war4 ,the value of the free or captive balloon has1 of course1 been clearly proven4 ,it has been of the greatest value for general observation work in the field4 ,it has been readily raised out of effective range of the enemy's batteries1 and from this position1 has looked down upon the forts1 cities1 or encampments4 ,it thus became a signal station which might direct gun fire with absolute accuracy1 and has been the only safe and reliable method for locating the presence of mines and submarines4 ,the dirigible balloon possesses all of the qualities of the free balloon and many more4 ,it can attack by day or night4 ,its search lights enable it to look down upon the enemy with pitiless accuracy4 ,it may thus gain information about forts and harbors1 which otherwise could not be approached4 ,the most completely mined harbor in the world has no terrors for such a visitor4 ,the great problem in warfare of patrolling the frontier of a country against possible invasion seems to be solved by the dirigible4 ,two or three men aboard a dirigible1 with a traveling radius of several hundred miles1 could do more effective work than several thousand men scattered along the frontier line4 ,for dispatch work the flying machine is expected to be indispensable in warfare4 ,the bearer of dispatches has always played an important part in war4 ,his work is often of the most perilous nature1 and his journeys1 at best1 are slow and uncertain4 ,the dispatch bearer1 driving an air-ship fifty miles an hour1 could ride high above the range of the enemy's guns4 ,these same vehicles of the air would doubtless be equipped with wireless telegraph apparatus1 so that they might send or receive messages1 and the aviator might talk freely with the entire country side1 directing a battery here1 silencing one there1 ordering an advance or conducting a retreat1 with unprecedented accuracy4 ,these arial fleets may also carry on deadly aggressive warfare4 ,the over sea raid will have greater terror than any ordinary invasion4 ,a fleet of dreadnaughts dirigibles1 assisted by fast cruisers of the air1 and many aroplane scouts1 would be extremely formidable4 ,an enemy's base line would be at the mercy of such an invasion4 ,within a few hours1 such a fleet might destroy the enemy's stores1 its railroads1 and its cities1 by dropping explosives or poisonous bombs4 ,in several recent aroplane flights1 8peace bombs0 have been aimed to strike a given mark1 and the shots have proven surprisingly accurate4 ,by using various instruments to determine directions1 it will be possible to drop such bombs with mathematical accuracy4 ,the bombs or missiles will be suspended by wires from beneath the air-ship and released by an electric current1 to give them a perfectly vertical direction4 ,when dropped from great altitudes1 the effect of such explosions will be difficult to withstand4 ,our great war-ships1 despite their steel sides1 will probably have to be completely remodelled before they can fight with this new enemy4 ,when an air-ship drops a bomb from a point directly above a fort or ship1 it will be absolutely out of the range of the enemy1 since to shoot directly up into the air would be to fire a boomerang which would quickly return and inflict serious damage4 ,an actual test was recently carried out in ,england1 when a thirteen pound gun fired at a balloon #ajjj feet in the air4 ,although the gun had an effective range of #djjj feet1 and the balloon was held captive1 it was not until the seventeenth shot had been fired that it was brought down4 ,it has also been proven that a rifle ball will be deflected by the draught from the propeller of an aroplane4 ,the flying machine promises to revolutionize warfare4 ,illustration3 ,three-quarters ,view of a ,flight at ,simms ,station1 ,november #af1 #aijd4 ,,chapter ,,viii ,,sports ,,of ,,the ,,air1 ,,aeroplanes ,any contest of air-ships makes excellent sport4 ,a city to city flight by aroplane1 for instance1 attracts greater crowds than could any procession or royal progress in the past4 ,the aronautical tournaments and meets already have been held from ,egypt in the ,east1 to ,california in the west4 ,let an aroplane soar higher than any has risen before1 stay aloft longer1 or make a new record for speed or distance1 and the news is instantly cabled around the world4 ,all who have gone aloft tell us that flying is the greatest sport in the world4 ,the free1 rapid glide we all enjoy in skating or coasting becomes speedier and smoother in an air-ship1 without exerting the least effort4 ,it is this sense of rapid motion which has made the automobile so popular1 and the air-ship improves upon the automobile1 just as the automobile improved on the lumbering coaches of the past4 ,once aloft1 the arial passenger glides with the swallow's swiftness4 8,now10 cried an enthusiastic ,frenchwoman1 after her first aroplane flight1 8now ,i understand why the birds sing40 ,as the aroplane is brought under better control1 we will see these contests grow more and more exciting4 ,the development of the new craft has been so rapid1 we have come to expect so much from it1 that the exhibition at which the world marvels to-day1 becomes the commonplace of to-morrow4 ,the early flights of the ,wright ,brothers at ,kitty ,hawk failed to attract much attention4 ,there had been so many announcements of successful flying machines that many were sceptical1 especially in ,europe1 and the world did not realize that the great day1 so long promised1 was dawning4 ,it was not till the ,wrights flew in ,north ,carolina that the world began to take the matter seriously4 ,every movement of the curious new craft was closely watched thereafter4 ,when one of the brothers went aloft the world knew it1 and crowds stood patiently before bulletin boards in ,new ,york1 ,london1 or ,sidney1 to count the minutes4 ,when he succeeded in staying aloft for an hour1 the waiting crowds in many widely separated cities1 broke into simultaneous cheers4 ,next came the trip to ,pau1 in ,france1 and other ,european cities1 and day by day the flights became longer and higher4 ,the brothers made double progress1 for while one was in ,southern ,europe increasing the time aloft1 the other was flying higher and higher in ,germany4 ,in these early days no attempt was made to fly across the country4 ,the aroplane merely flew around and around some large field1 and the distance traversed was calculated more or less accurately4 ,after the triumphant return of the ,wrights to ,america1 a cross-country run was made at ,fort ,myer1 to show the ,government that the aroplane was more than a toy4 ,a flight of twenty miles was made over a rough1 mountainous country and several deep valleys4 ,the air of the valleys drew the machine down with a dangerous rush1 but the aviator pluckily worked his way higher1 and passed over it in safety4 ,shortly after this1 during the ,hudson-,fulton ,celebration in ,new ,york1 ,mr4 ,wilbur ,wright rose from ,governor's ,island in ,new ,york harbor1 encircled the ,statue of ,liberty1 and again sailed high above the river north to ,grant's ,tomb1 and returned to the starting point4 ,each of these feats was1 in a peculiar sense1 record breaking4 ,illustration3 ,front ,view of the ,flight of the ,wright ,aroplane1 ,october #d1 #aije4 ,meanwhile1 a flock of aviators were making ascensions in biplanes and monoplanes of many designs in ,france4 ,their first attempts to fly were made1 as a rule1 in a great field on the outskirts of ,paris1 where immense crowds gathered to watch them4 ,as the aviators gained confidence in their craft1 the flights rapidly became longer and higher1 and short cross-country flights were made4 ,these cross-country and over-water flights quickly out-distanced those made in ,america1 and this lead once gained1 was kept up4 ,there are several reasons why ,france1 after ,america pointed the way1 should have overtaken1 and1 in some respects1 out-distanced her4 ,there have been more aviators in ,france4 ,the prizes offered for flights of various kinds1 have been ten times more numerous and valuable in ,france than in any other country1 and this naturally invited competition4 ,the example of ,france in offering valuable prizes for long flights has since been followed in the ,united ,states4 ,it should be borne in mind1 again1 that the level stretches of country common in ,europe1 offers fewer difficulties for the pilot of the aroplane than the rough1 mountainous1 or even hilly country often encountered in ,america4 ,it is possible to fly hundreds of miles in the south of ,france or in ,italy and pass over country like a great parade ground4 ,when a long-distance flight is made in ,america1 rivalling or surpassing those made abroad1 it is probable that it has required far more skill and daring than similar ,european flights4 ,the ,french1 again1 excel in building light1 serviceable motors1 suitable for aroplanes1 and no small part of the success of the ,french air craft is due to this skill4 ,the cross-country trips were quickly extended4 ,after several successful short flights1 ,henry ,farman surpassed all records by traveling for eighty-three miles across country in ,france4 ,the great feat was now to cross the ,english ,channel4 ,a prize of #e1jjj was offered by a ,london newspaper for the first channel flight4 ,two attempts were made by a young ,frenchman1 ,hubert ,latham1 but both times1 after sailing out for several miles over the sea1 some accident befell his machine1 and he was thrown into the water4 ,undaunted by these failures1 another ,frenchman1 ,louis ,bleriot1 started early one ,sunday morning1 ,june #be1 #aiji1 from a point near ,calais1 ,france1 and landed safely at ,dover on the ,english side4 ,shortly after this1 still another ,frenchman1 ,de ,lesseps1 flew from the ,french coast to ,england in safety4 ,the richest of the aviation prizes1 a purse of #ej1jjj1 had meanwhile been offered for a successful trip by a heavier-than-air machine from ,london to ,manchester1 a distance of #aga miles4 ,several attempts had been made to cover this distance1 but without success4 ,it was finally won1 however1 under very dramatic circumstances4 ,two aviators1 an ,englishman named ,white and a ,frenchman named ,paulhan1 actually raced for the goal4 ,the ,french machine got away first1 but was followed by the ,english machine close on his heels--or should we say propellers8 ,the greater part of the race took place at night in a high wind1 and1 in the upper air lanes1 intensely cold weather4 ,paulhan succeeded in flying #aag miles without coming down1 rushing along through the night at top speed1 with the dread that every sound behind him came from the machine of his rival4 ,when he was forced to land for fuel1 he worked with feverish haste1 fearing that every second's delay might cost him the coveted prize4 ,several times the crowd about him1 deceived by some night bird1 cried 8,here comes ,white60 ,as a matter of fact1 ,white was but a few miles behind4 ,the fuel tank filled1 ,paulhan drove his machine full speed into the sky1 and did not land till he had completed the journey and won the prize4 ,there was naturally a great demand for a similar journey in ,america1 and the aviator and the prize were soon found4 ,for several years there had been a standing prize of #aj1jjj for the first successful flight between ,new ,york and ,albany1 over the ,hudson ,river1 the course taken by ,robert ,fulton in his famous trip by steamboat in #ahji4 ,an effort was made to cover the distance by dirigible balloon without success4 ,an attempt was made by aroplane on ,may1 #aiaj1 by ,glenn ,h4 ,curtiss1 the winner of the grand prize for speed in the aviation meeting at ,rheims4 ,curtis started from ,albany1 in order to face the air currents which drew up the river4 ,after waiting for several days for fair weather1 he finally got away early one morning1 and1 following the course of the ,hudson ,river1 made the flight to ,poughkeepsie1 seventy-five miles south1 without mishap1 when he landed for fuel4 ,again rising into the air1 he started south1 traveling with such speed1 that he outdistanced the special train which was following him4 ,a difficult problem in aviation was met in passing over the ,highlands1 a rugged mountainous section1 through which the river cuts a deep1 tortuous channel4 ,curtiss rose to a height of more than #ajjj feet1 but the treacherous air currents drew him down and tossed him about at perilous angles4 ,he fought his way1 foot by foot1 finally bringing his craft to an even keel4 ,on reaching ,new ,york1 he landed in the upper section of the city for gasolene1 and once more rising above the ,hudson ,river1 flew swiftly to the riotous clamor of every whistle in the great harbor beneath him1 to a safe landing at ,governor's ,island4 ,the first great city to city and return aroplane trip was made a few days later1 between ,new ,york and ,philadelphia4 ,a new aspirant for these honors was ,mr4 ,charles ,k4 ,hamilton1 who had amazed everyone with his daring driving4 ,he was engaged to fly over the course for #aj1jjj1 offered by a ,new ,york and a ,philadelphia newspaper4 ,he carried with him letters from the ,governor of ,new ,york and the ,mayor of ,new ,york ,city to the ,governor of ,pennsylvania and the ,mayor of ,philadelphia4 ,he also took aloft a number of 8peace bombs10 which he dropped along the route to show how accurate might be the aim of a war aroplane4 ,the start was made early on the morning of ,june #ac1 from ,governor's ,island in ,new ,york harbor4 ,a special train was held in readiness to follow him4 ,after rising to a considerable altitude1 ,hamilton flew in great circles about the island to try his wings1 and then1 signaling that all was ready1 darted off to the south4 ,he quickly picked up his special train1 and1 at a pace of almost a mile a minute1 flying hundreds of feet in air1 sped on to ,philadelphia4 ,it was estimated that more than #a1jjj1jjj people had gathered along the route to cheer him4 ,hamilton had laid out a regular time-table before starting1 and so perfect was his control of the machine1 that he passed town after town on time to the minute like a railroad train4 ,the run to ,philadelphia eighty miles away1 was made without alighting and without mishap of any kind4 ,hamilton flew over the open field selected for landing1 circled it three times to show that he was not tired in the least1 and settled down as lightly as a bird4 ,he was received by the ,governor of ,pennsylvania and the ,deputy ,mayor of ,philadelphia1 to whom he delivered his messages and received similar letters in reply to bring back to ,new ,york4 ,after a brief rest of little more than one hour1 ,hamilton was once more in the sky1 flying across-country at express speed4 ,he set such a pace1 that his special train was left far behind1 and it was only by running at the rate of seventy-five miles an hour1 that it finally overtook him4 ,hamilton drew far ahead of the train on the return trip which was made in much faster time4 ,the wind was favorable1 and ,newark1 eighty miles1 was reached at the rate of fifty miles an hour4 ,with the goal practically in sight1 ,hamilton's engine began working badly4 ,he pushed on1 until he found himself in absolute danger1 when he decided to descend4 ,from such high altitudes1 the appearance of the ground is very deceptive4 ,hamilton chose what appeared to be a smooth piece of green grass and dropped to it1 only to discover that he had settled in a marsh4 ,the fault in the engine was quickly remedied1 but now the ground proved too soft for him to rise4 ,in trying to rise he broke his propeller1 and another delay followed1 while a new propeller was hurried from ,new ,york4 ,he finally succeeded1 however1 in rising and completing his trip to ,governor's ,island1 thus making the round trip in a day and winning the prize4 ,so rapid is the advance in the new science1 that each aviation meet sets a new and more difficult standard4 ,at first1 people marvelled to see an aroplane rising but a few feet from the ground1 but such feats soon became commonplace4 ,within a few months1 prizes were offered for the machine staying aloft for the longest time4 ,the element of speed was next considered1 and the aroplanes sailed around a race course against time4 ,the highest altitude now became a popular test feat4 ,the pilots soon found themselves in such complete control of their machines that they gave exhibitions of landing by the force of gravity alone4 ,the aroplane would work its way upward in great spirals1 and then1 shutting off all power1 coast down at terrifying angles on the unsubstantial air4 ,it is from such tests as these that there will gradually evolve the airships of the future1 the terrible engines of war1 the air liners for commerce1 and the light and speedy pleasure craft4 ,transcriber's ,notes3 ,variations in spelling and hyphenation are retained4 ,perceived typographical errors have been changed4