,this file was produced from page images at the ,internet ,archive4 ,transcriber's ,note ,this book was transcribed from scans of the original found at the ,internet ,archive and at ,google ,books4 ,i have rotated some images4 ,tables are treated as images4 ,there are two versions of this book3 the first contains both parts and the second is published as two volumes with ,examination ,papers at the end of each1 which the student would return to the ,american ,school of ,correspondence for credit4 ,i have included these ,examination ,papers at the end of each part4 ,illustration3 ,,twenty ,,horsepower ,,neuport ,,monoplane ,,making ,a ,,landing ,this ,photograph ,protected ,by ,international ,copyright ,,building ,,and ,,flying ,,an ,,aeroplane ,a ,,practical ,,handbook ,,covering ,,the ,,design1 ,,construction1 ,,and ,,operation ,,of ,,aeroplanes ,,and ,,gliders ,by ,,charles ,b4 ,,hayward ,,member1 ,,the ,,aeronautical ,,society2 ,,member1 ,,society ,,of ,,automobile ,,engineers2 ,,formerly ,,secretary1 ,,society ,,of ,,automobile ,,engineers2 ,,formerly ,,engineering ,,editor1 ,,the ,,automobile ,,illustrated ,,chicago ,,american ,,school ,,of ,,correspondence #aiab ,copyright #aiab by ,american ,school of ,correspondence ,entered at ,stationers' ,hall1 ,london ,all ,rights ,reserved ,,building ,,and ,,flying ,,an ,,aeroplane ,,introduction ,the field of aviation has1 from the inception of successful flight by the ,wright ,brothers1 had a wonderful fascination for the amateur mechanic4 ,at first the strong element of mystery in the movements of this monster man-ridden bird appalled him1 but an examination of approved designs has removed the mystery and has assured him that he can1 with his own hands and at a cost well within his reach1 build his own machine in his own back yard4 ,but in this ease of accomplishment lies a danger1 namely1 the belittling of the value of accurate design and the misjudging of the true importance of small things4 ,the inventive mind usually believes itself capable of making improvements in almost anything1 and the aeroplane inventor is no exception to the rule4 ,filled with the confidence born of ignorance1 and with only the knowledge he has gleaned from newspaper and magazine accounts of the popular types of machines1 he works out a brand new design4 ,the usual1 in fact1 the invariable result is failure1 discouragement1 and a loss of time and money4 ,how much more sensible for the young inventor to build his first machine without varying in one particular from a tried and proved model1 leaving his flights of inventive fancy to his later years of maturer knowledge and judgment4 ,the author of this little book has followed1 in both biplane and monoplane models1 the well-known types of ,curtiss and ,bleriot1 choosing each as the simplest representative of its class in construction and design4 ,it is hoped that the book may not only be of assistance to the amateur builder1 but may also be the means of turning the too confident inventor into safer and more established paths4 ,illustration3 ,,harry ,,atwood ,,in ,,his ,,burgess ,,hydroaeroplane ,,skimming ,,over ,,the ,,surface ,,of ,,marblehead ,,bay ,,building ,,and ,,flying ,,an ,,aeroplane 4444444444444444444444444444444444 ,,introduction 4444444444444444444444444444444444444444 444444444444 ,,part #a 4444444444444444444444444444444444444444 444444444444444444 ,,building ,,aeroplane ,,models 4444444444444444444444444444444444444 ,,building ,a ,,glider 4444444444444444444444444444444444444444 44444 ,,building ,a ,,curtiss ,,biplane 444444444444444444444444444444444444 ,,details ,,of ,,construction 444444444444444444444444444444444444444 ,,part ,,ii 4444444444444444444444444444444444444444 44444444444444444 ,,building ,a ,,bleriot ,,monoplane 4444444444444444444444444444444444 ,,art ,,of ,,flying 4444444444444444444444444444444444444444 444444444 ,,accidents ,,and ,,their ,,lessons 44444444444444444444444444444444444 ,,amateur ,,aviators 4444444444444444444444444444444444444444 444444 ,,part #a ,one of the commonest phases of interest in aviation is the desire to build a flying machine4 ,in fact1 this is very frequently the first thing the experimenter undertakes after having gone into the theory of flight to some extent4 ,only too often1 no effort whatever is made to get beyond theory and the machine is an experiment in every sense of the word4 ,an experience of this nature is costly--far more so than is agreeable for the student1 and is likely to result in disgusting him with aviation generally4 ,there are hundreds of schemes and principles in the art that have been tried again and again with the same dismal failure in the end4 ,refer to the story of the ,wright ,brothers and note how many things they mention having tried and rejected as worse than useless4 ,about once in so often someone rediscovers some of these things and1 having no facilities for properly investigating what patent attorneys term the prior art 7everything that has gone before1 from the beginning of invention1 or at least patented invention7 becomes possessed of the idea that he has hit upon something entirely novel and wholly original4 ,there is no desire in the present work to discourage the seeker after new principles--undoubtedly there are many yet to be discovered4 ,the art of flight is in its infancy and there is still a great deal to be learned about it1 but there is no more discouraged inventor than he who-discovers a principle and1 after having experimented with it at great expense1 finds that it is only one of many things that numerous others have spent considerable money in proving fallacious1 a great many years ago4 ,if it be your ambition to build a flying machine and you believe that you have discovered something new of value1 it will be to your interest to retain a responsible patent attorney to advise you as to the prior art1 before expending any money on its construction4 ,you will find it very much more economical in the end4 ,there are probably not more than half a dozen men alive in this country today who know all the schemes that won't work4 ,the average seeker after knowledge is assuredly not likely to be one of these few1 so that until he knows he is working along new and untried lines that give promise of success1 it will pay him to stick to those that have proved successful in actual practice4 ,in other words1 to confine his efforts in the building line to a machine that experience has demonstrated will fly if properly constructed and1 what is of equal importance1 skilfully handled4 ,build a machine1 by all means1 if you have the opportunity4 ,it represents the best possible experience4 ,but as is pointed out under the ,art of ,flying1 take a few lessons from some one who knows how to fly1 before risking your neck in what is to you a totally untried element4 ,even properly designed and constructed machines are not always ready to fly4 ,an aeroplane needs careful inspection of every part and adjustment before it is safe to take to the air in it1 and to be of any value this looking-over must be carried out by an experienced eye4 ,,building ,,aeroplane ,,models ,the student may enter upon the business of building to any extent that his inclination or his financial resources or his desire to experiment may lead him4 ,the simplest stage1 of course1 is that of model building and there is a great deal to be learned from the construction and flying of experimental models4 ,this has become quite a popular pastime in the public schools and some very creditable examples of work have been turned out4 ,the apparent limitations of these rubber-band driven models need not discourage the student1 as some of the school-boy builders have succeeded in constructing models capable of flying a quarter mile in still air and their action in the air is wonderfully like the full-sized machines4 99,models with ,rubber-,band ,motor994 ,the limitations of the available power at command must be borne in mind1 as the rubber-band motor is at best but a poor power plant4 ,it is accordingly not good practice to have the spread of the main planes exceed #bd inches1 though larger successful models have been built4 ,in attempting to reproduce any of the well-known models1 difficulty is often experienced in accommodating the rubber-band motor to them1 as even where the necessary space is available1 its weight throws the balance out entirely1 and the result is a model that will not fly4 ,this has led to the production of many original creations1 but these1 while excellent flyers1 would not serve as models for larger machines1 as of necessity they have been designed around their power plants4 ,the rubber bands for this purpose may be purchased of any aeronautic supply house4 ,the most practical method of mounting the motor is to attach it to the rear end of the fuselage1 usually a single stick1 which is accordingly made extra long for that purpose4 ,at the other end it is attached to a bent wire fastened to the propeller in order to revolve the latter4 ,an easy way to wand up the motor is to employ an ordinary egg beater1 modified as described below1 or a hand drill1 inserting a small wire yoke in the jaws in place of the usual drill1 or bit4 ,this yoke is placed so as to engage the propeller blades1 and the latter is then turned in the opposite direction1 storing energy in the rubber band by twisting its strands tightly4 ,illustration3 ,fig4 #a4 ,details of ,main ,frame of ,rubber-,band ,driven ,aeroplane ,model ,for those students who do not care to undertake an original design at the outset1 or who would prefer to have the experience gained by building from a plan that has already been tried1 before attempting to originate1 the following description of a successful model is given4 ,this model can not only be made for less than the models sold at three to five dollars1 but is a much more efficient flyer1 having frequently flown #gjj feet4 ,main ,frame4 ,the main frame of the model monoplane consists of two strips ,a of spruce1 each #bh inches long1 and measuring in cross section #a_/d by #c_/h of an inch4 ,as shown in ,fig4 #a1 the two strips are tied together at the front with strong thread and are then glued1 the glue being spread over and between the windings of the thread1 ,figs4 #a and #b4 ,the rear ends of these strips are spread apart #d #a_/d inches to form a stout triangular frame1 and are tied together by cross bars of bamboo ,b and ,c which are secured to the main strips ,a by strong thread and glue4 ,illustration3 ,fig4 #b4 ,details of ,forward ,skids of ,aeroplane ,model ,propellers4 ,the propellers ,d are two in number and are carried by the two long strips ,a4 ,each propeller is #e inches in diameter1 and is whittled out of a single block of white pine4 ,the propellers have a pitch of about #aj inches4 ,after the whittling is done they are sandpapered and coated with varnish4 ,the thickness of the wood at the hub ,e1 ,fig4 #c1 of the propeller should be about #e_/h inch4 ,at the rear ends of the strips ,a1 bearing blocks ,e are secured4 ,these bearing blocks are simply small pieces of wood projecting about #e_/h inch laterally from the strips ,a4 ,they are drilled to receive a small metal tube ,t 7steel1 brass1 or copper71 through which tube the propeller shaft ,t passes4 ,illustration3 ,fig4 #c4 ,details of ,propeller and ,rudder of ,aeroplane ,model ,the propeller shaft itself consists of a piece of steel wire passing through the propeller hub and bent over the wood1 so that it can not turn independently of the propeller4 ,any other expedient for causing the propeller to turn with the shaft may obviously be employed4 ,small metal washers ,t1 at least three in number1 are slipped over the propeller shaft so as to lie between the propeller and the bearing block4 ,that portion of the propeller shaft which projects forwardly through the bearing block ,e is bent to form a hook ,t4 ,to the hook ,t rubber strips ,t by which the propellers are driven1 are secured4 ,the rubber strips are nearly as long as the main strips ,a4 ,at their forward ends they are secured to a fastening consisting of a double hook ,g ,h1 the hook ,g lying in a horizontal plane1 the hook ,h in a vertical plane4 ,the hook holds the rubber strips1 as shown in ,figs4 #a and #d1 while the hook ,h engages a hook ,t4 ,this hook is easily made by passing a strip of steel wire through the meeting ends of the main strips ,a1 the portions projecting from each side of the strips being bent into the hooks ,i4 ,skids4 ,three skids are provided1 on which the model slides1 one at the forward end1 and two near the rear end4 ,all are made of bamboo4 ,as shown in ,fig4 #b the front skid may be of any length that seems desirable4 ,a #f-;inch piece of bamboo will probably answer most requirements4 ,this piece ,n is bent in opposite directions at the ends to form arms ,z and ,u1 ,the arm ,z is secured to the forward ends of the two strips ,a1 constituting the main frame1 by means of thread and glue4 ,the strips and skid are not held together by the same thread1 but the skid is attached to the two strips after they have been wound4 ,hence1 there are two sets of windings of thread1 one for the two strips ,a themselves1 and another for the skid and the strips4 ,strong thread and glue should be used1 as before4 ,in order to stiffen the skid1 two bamboo struts ,w will be found necessary4 ,these are bent over at the ends to form arms ,v1 ,fig4 #b4 ,each of the arms is secured to the under side of a strip ,a by strong thread and glue4 ,the arms ,x are superimposed and tied to the bamboo skid ,v with strong thread and glue4 ,illustration3 ,fig4 #d4 ,details of ,rear ,skids on ,aeroplane ,model ,the two rear skids1 of which one is shown in ,fig4 #e1 consist each of two #e-;inch strips of bamboo ,s1 likewise bent at either end in opposite directions to form arms ,s and ,s1 ,the arms ,s are fastened to the strips ,a by strong thread and glue4 ,to stiffen the skids a strut ,c is provided for each skid4 ,each strut consists of a #c-;inch strip of bamboo bent over so as to form arms ,c4 ,strong thread and glue are employed to fasten each strut in position on the strip and the skid4 ,in the crotch of the triangular space ,b1 a tie bar ,j1 ,figs4 #d and #e1 is secured by means of thread and glue4 ,this tie bar connects the two skids1 as shown in ,figs4 #a and #d1 and serves to stiffen them4 ,the triangular space ,b is covered with paper1 preferably bamboo paper4 ,if bamboo paper is not available1 parchment or stiff light paper of some kind may be used4 ,it does not need to be waterproof4 ,thus triangular fins are formed which act as stabilizing surfaces4 ,illustration3 ,fig4 #e4 ,enlarged ,details of ,one ,rear ,skid1 ,aeroplane ,model ,main ,planes4 ,the main planes are two in number1 but are different in size4 ,contrary to the practice followed in large man-carrying monoplanes1 the front supporting surface is comparatively small in area and the rear supporting surface comparatively large4 ,these supporting surfaces ,l and ,p are shown in detail in ,figs4 #f and #g4 ,it has been found that a surface of considerable area is required at the rear of the machine to support it1 hence1 the discrepancy in size4 ,although the two supporting surfaces differ in size1 they are made in exactly the same manner1 each consisting of a thin longitudinal piece of spruce ,r1 to which cross pieces of bamboo ,q are attached4 ,in the smaller plane1 ,fig4 #g1 all the cross pieces are of the same size4 ,in the larger plane1 ,fig4 #f1 the outer strips ,s are somewhat shorter than the others4 ,their length is #b #a_/b inches1 whereas the length of the strips ,q is #c #a_/b inches4 ,in order to allow for the more gradual tapering of the plane1 around the outer ends of the longitudinal strips ,r and the ribs ,q a strip of bamboo is tied4 ,the frame1 composed of the longitudinal strip and cross strips1 is then covered with bamboo paper1 parchment paper1 or any other style light paper1 which is glued in place4 ,illustration3 ,fig4 #f4 ,details of ,main ,plane of ,aeroplane ,model ,illustration3 ,fig4 #g4 ,details of ,smaller ,plane of ,aeroplane ,model ,the forward or smaller plane has a spread of #h #a_/b inches and a depth of #c #a_/d inches4 ,the main plane has a spread of #bj inches and a depth of #c #a_/b inches at the widest portion4 ,the author has made experiments which lead him to believe that the tapering form given to the outer edge of the plane improves both the stability and endurance of the machine4 ,the planes are slightly arched1 although it will be found that flat planes will also give good results4 ,the rear edge of the main plane should be placed #d #a_/d inches distant from the forward edge of the propeller block ,e4 ,the front plane must have a slight angle of incidence1 just how much depends upon the weight of the machine1 the manner in which it is made1 and various other factors4 ,this angle of incidence is obtained by resting the front portion of the plane on two small blocks ,n1 ,figs4 #a and #b1 which are fastened to the top of the main strip ,a by strong thread and glue4 ,illustration3 ,fig4 #h4 ,device for ,winding up ,rubber-,band ,motors ,the height of the blocks ,n should be about #a_/d inch1 although this will necessarily vary with the machine4 ,the blocks should be placed approximately #d inches from the forward end of the machine4 ,the front end of the forward plane should be elevated about #a_/d inch above the rear end1 which rests directly on the main strips4 ,both the front and rear planes ,l and ,p are removably lashed to the frame by means of ordinary rubber bands1 which may be obtained at any stationery store4 ,these rubber bands are lettered ,m in ,fig4 #a4 ,winding the ,rubber ,strips4 ,the rubber strips can be most conveniently wound up by means of an egg beater1 slightly changed for the purpose4 ,fig4 #h4 ,the beater and the frame in which it is carried are entirely removed1 leaving only the main rod ,e1 which is cut off at the lower end so that the total length is not more than #b or #c inches4 ,the two brass strips ,d on either side of the rod1 which are attached to the pinion ,q meshing with the large driving wheel ,h1 are likewise retained4 ,a washer ,f is soldered to the rod near its upper end1 so as to limit the motion of the small pinion and the brass strips ,d attached to the pinion4 ,next a wire ,b is bent in the form of a loop1 through which loop the central rod passes4 ,the ends of the wire are soldered to the side strips ,d4 ,lastly1 a piece of wire ,c is bent and soldered to the lower ends of the side strips4 ,in order to wind up a rubber strip1 the strip is detached from the forward end of the model1 and the hook ,a slipped over the wire ,c4 ,the opposite end of the rubber band is held in any convenient manner4 ,naturally the two strips must be wound in opposite directions1 so that the two propellers will turn in opposite directions4 ,by stretching the rubber while it is being wound1 more revolutions can be obtained4 ,it is not safe to have the propeller revolve more than #gjj times4 ,the ratio of the gears of the egg-beater winder can be figured out so that the requisite number of twists can be given to the rubber bands for that particular number of revolutions4 ,model with ,gasoline ,motor4 ,the next and somewhat more ambitious stage is the building of a power-driven model1 which has been made possible by the manufacture of miniature gasoline motors and propellers for this purpose4 ,motors of this kind1 weighing but a few pounds and capable of developing #a_/d horse-power or more1 may be had complete with an #ah-;inch aluminum propeller and accessories for about #de4 ,as is the case with the rubber-band driven model1 the monoplane is the simplest type to construct1 and the dimensions and details of an aeroplane of this type are given here4 ,it will be found that a liberal-sized machine is required to support even such a small motor4 ,the planes1 ,fig4 #i1 have a spread of #g feet #h inches from tip to tip1 each wing measuring #c #a_/b feet by a chord of #ae inches4 ,they are supported on a front and rear wing spar of spruce1 #a_/b by #c_/h inch in section1 while the ribs in both the main plane and the rear stabilizing plane measure #a_/h by #a_/b inch in cross section4 ,there are eight of these spruce ribs in the main plane1 and they are separately heated and curved over a ,bunsen burner1 or over a gas stove1 which is the same tiling4 ,they are then nailed to the wing spars #f inches apart4 ,the main spars of the fuselage are #g feet long and they are made of #a_/b by #c_/h inch spruce1 the struts being placed #a #a_/b feet apart1 measuring from the rear1 with several intermediate struts to brace the engine bed4 ,instead of using strut sockets for the fuselage1 which would increase the cost of construction unnecessarily1 a simple combination of a three-way wire fastener and a wire nail may be resorted to4 ,the shape of these fasteners is shown at ,a in ,fig4 #i4 ,they may be cut out of old cracker boxes or tin cans 7sheet iron7 with a pair of shears1 the holes in the ends being made either with a small drill or by driving a wire nail through the metal placed on a board1 and filing the burrs off smooth4 ,a central hole must also be made for the #a #a_/b inch wire nail which is driven through the main spar and the fastener then slipped over it4 ,as indicated1 this nail also serves to hold the strut4 ,a drop of solder will serve to attach the fastener to the nail4 ,the front of the fuselage is #i inches square1 tapering down to #f inches at the rear4 ,the height of the camber of the main planes is #a #a_/b inches and the angle of incidence is #g degrees1 measured with relation to the fuselage4 ,the non-lifting tail plane at the rear which is to give the machine longitudinal stability1 measures #d feet in span by #ad inches in depth4 ,illustration3 ,fig4 #i4 ,details of ,power-,driven ,aeroplane ,model ,the running gear or front landing frame is made of #a_/b inch square spruce1 all joints being made with #a_/af by #a inch bolts4 ,aluminum sleeves1 procurable at an aeronautic supply house1 are employed for the attachment of the rubber springs and the radius rods running down to the wheels1 which may also be purchased ready to install4 ,old bicycle wheels will serve the purpose admirably4 ,light steel tubes #a_/b inch in diameter are used to run these aluminum sleeves on4 ,two other steel tubes are joined to the lower corner of the frame by flattening them at the ends and drilling with a small hole for a nail4 ,these are run diagonally up to the fuselage and serve as buffers to take the shocks of landing4 ,for bracing the wings1 two similar tubes are fastened to form a pyramid on top of the main plane just back of the engine4 ,from these1 guys are run to the wings as shown4 ,the engine bed is made of #a_/b by #c_/d-;inch white pine1 and to make it solid it is carried as far back as the rear edge of the main plane4 ,the batteries and coil are directly attached to this plane1 care being taken in their placing to preserve the balance of the machine4 ,the rudder measures #ad inches square and is made of #c_/h-;inch square spruce1 reinforced with tin at the joints1 as it is necessary to make the frame perfectly rigid4 ,both sides are covered with fabric4 ,in this case a #a-;horse-power motor furnishes the necessary energy and it is fitted with an #ah-;inch aluminum propeller which it is capable of turning at #b1djj r4p4m4 ,the carbureter and gas tank are made integral1 and the gasoline and oil are both placed in this tank in the proportion of about four parts to one1 in order to save the weight of an extra tank for oil4 ,flights of half a mile are possible with this model in calm weather1 but a great deal of measuring and testing of the fuel is necessary in order to regulate the flight1 and grass-cutting should be practiced by the builder in order to properly regulate the machine4 ,trials have shown that the flat non-lifting tail on the fuselage gives excellent longitudinal stability1 the machine rising nicely and making its descent very easy angle1 so that it is seldom damaged by violent collisions in landing4 ,,building ,a ,,glider ,the building of hand- or power-driven models does not suffice to give that personal experience that most students are desirous of obtaining4 ,the best method of securing this is to build a glider and practice with it4 ,any flying machine without a motor is a glider and the latter is the basis of the successful aeroplane4 ,in the building of an aeroplane the first thing constructed is the glider1 i4e4 the frame1 main planes1 stabilizing planes1 elevators1 rudders1 etc4 ,it is only by the installation of motive power that it becomes a flying machine4 ,the biplane will be found the most satisfactory type of glider as it is more compact and therefore more easily handled1 which is of great importance for practicing in a wind4 ,the generally accepted rule is that #aeb square feet of surface will sustain the weight of the average man1 about #agj pounds1 and it will be apparent that the length of the glider will have to be greater if this surface is to be in the form of a single plane than if the same amount is obtained by incorporating it in two planes--the biplane4 ,a glider with a span of #bj feet and a chord of #d feet will have a surface of #aeb square feet4 ,so far as learning to balance and guide the machine are concerned1 this may be mastered more readily in a small glider than in a large one1 so that there is no advantage in exceeding these dimensions--in fact1 rather the reverse1 as the larger construction would be correspondingly more difficult to handle4 ,the materials necessary consist of a supply of spruce1 linen shoe thread1 metal sockets1 piano wire1 turnbuckles1 glue1 and closely-woven1 light cotton fabric for the covering of the planes4 99,main ,frame994 ,the main frame or box cell is made of four horizontal beams of spruce #bj feet long and #a #a_/b by #c_/d inch in section4 ,they must be straight-grained and perfectly free from knots or other defects4 ,if it be impossible to obtain single pieces of this length1 they may be either spliced or the glider may be built in three sections1 consisting of a central section #h feet long1 and two end sections each #f feet in length1 this form of construction also making the glider much easier to dismantle and stow in a small space4 ,in this case1 the ends of the beams of each end section are made to project beyond the fabric for #aj inches and are slipped into tubes bolted to corresponding projections of the central section4 ,these tubes are drilled with three holes each and bolts are passed through these holes and corresponding holes in the projecting ends after they have been fitted into the tubes1 and drawn up tightly with two nuts on each bolt to prevent shaking loose4 ,ordinary #c_/af-;inch stove bolts will serve very nicely for this purpose4 ,the upper and lower planes forming the box cell1 are held apart by #ab struts1 #d feet long by #g_/h inch diameter1 preferably of rounded or oval form with the small edge forward to minimize the head resistance4 ,it is only necessary to space these equally1 starting from both ends2 this will bring the splices of the demountable sections in the center of the square on either side of the central section4 ,the main ribs are #c feet long by #a #a_/d- by #a_/b-;inch section and their placing should coincide with the position of the struts4 ,between these main ribs are placed #da small ribs1 equally spaced and consisting of pieces #d feet long by #a_/b inch square4 ,these1 as well as all the other pieces1 should have the sharp edges of the square rounded off with sand paper4 ,the ribs should have a camber of #b inches in their length and the simplest method of giving them this is to take a piece of plank1 draw the desired curve on it1 and then nail blocks on both sides of this curve1 forming a simple mould4 ,the rib pieces should then be steamed1 bent into this mould1 and allowed to dry1 when they will be found to have permanently assumed the desired curvature4 ,meanwhile1 all the other pieces may be shellaced and allowed to dry4 ,illustration3 ,fig #aj4 ,wrong and ,right way of ,making a ,wire ,joint ,assembling the ,planes4 ,to assemble the glider1 the beams are laid out on a floor1 spaced the exact distance apart1 i4e41 #c feet1 and exactly parallel--in the demountable plan1 each section is assembled independently4 ,the main ribs are then glued in place and allowed to set1 after which they are strongly bound in place with the linen thread1 and the various layers of thread given a coating of hot glue as they are put on4 ,this method is not arbitrary1 but it is simple and gives the lightest form of construction4 ,if desired1 tie-plates1 clamps1 or any other light method of fastening may be employed4 ,this also applies to the ribs4 ,they are assembled by placing them flush with the front beam and allowing them to extend back a foot beyond the rear beam1 arched side up in every case4 ,they may be glued and bound with thread1 held by clamps1 or nailed or screwed into place1 care being taken to first start a hole in the beam with an awl and to dip the nails in soft soap to prevent splitting the wood4 ,twenty-one ribs1 spaced one foot apart1 are used in the upper plane1 and #bj in the lower1 owing to the space left for the operator in the latter4 ,for fastening the two planes together1 whether as a whole or in sectional units1 #bd aluminum sockets will be required4 ,these may be purchased either ready to fit1 or an effective substitute made by sawing short lengths of steel tubing1 slitting them with the hack saw an inch from the bottom1 and then flattening out and drilling the right-angle flanges thus formed to take screws for attaching the sockets to the beams4 ,in case these sockets are bought1 they will be provided with eye bolts for the guy wires2 if homemade1 they may have extra holes drilled in the edges of the flanges for this purpose or some simple wire fastener such as that described in connection with the power-driven model may be used1 heavier metal1 however1 being employed to make them4 ,the sockets should all be screwed to the beams at the proper points and then the struts should be forced into them4 ,the next move is to tie the frame together with guy wires4 ,no4 #ab piano wire being employed for this purpose4 ,each rectangle is trussed by running diagonal guy wires from each corner to its opposite4 ,to pull these wires taut1 a turnbuckle should be inserted in each and after the wire has been pulled as tightly as possible by hand1 it should be wound upon itself to make a good strong joint1 as shown at ,b1 ,fig4 #f4 ,a fastening as shown at ,a will pull out under comparatively little strain and is not safe4 ,as is the case with most of the other fittings1 these turnbuckles may be bought or made at home1 the simple bicycle type of turnbuckle mentioned in connection with ,building a ,curtiss1 being admirably adapted to this purpose4 ,in fact1 the construction of the latter will be found to cover the requirements of the glider1 except that the ribs are simpler and lighter1 as already described1 and no provision for the engine or similar details is necessary4 ,all the guy wires must be tightened until they are rigid1 and the proper degree of tension for them may be simply determined in the following manner3 ,after the entire frame is wired1 place each end of it on a saw horse so as to lift it two or three feet clear of the floor4 ,stand in the opening of the central section1 as if about to take a glide1 and by grasping the forward central struts1 raise yourself from the floor so as to bring your entire weight upon them4 ,if properly put together the frame will be rigid and unyielding1 but should it sag even slightly1 the guy wires must be uniformly tightened until even the faintest perceptible tendency to give under the weight is overcome4 ,stretching the ,fabric4 ,the method of attaching the fabric will be determined by whether the glider is to be one piece or sectional1 and the expense for this important item of material may be as little or as much as the builder wishes to make it4 ,some employ rubberized silk1 others special aeronautic fabrics1 but for the purposes of the amateur1 ordinary muslin of good quality1 treated with a coat of light varnish after it is in place1 will be found to serve all purposes4 ,the cloth should be cut into #d-;foot strips1 glued to the front horizontal beams1 stretched back tightly1 and tacked to both the rear horizontal beams and to the ribs4 ,tacks should also supplement the glue on the forward beams and the upholstery style should be used to prevent tearing through the cloth4 ,in case the glider is built in sections1 the abutting edges of the cloth will have to be reinforced by turning it over and stitching down a strip one inch wide1 and it will make this edge stronger if an extra strip of loose fabric be inserted under the turn before sewing it down4 ,eyelets must then be made along these edges and the different sections tightly laced together when assembling the glider4 ,it is also desirable to place a strip of cloth or light felt along the beams under the tacks to prevent the cloth from tearing out under the pressure4 ,to form a more comfortable support for the operator1 two arm pieces of spruce1 #c feet by #a inch by #a #c_/d inches1 should be bolted to the front and rear beams about #ad inches apart over the central opening left in the lower plane4 ,these will be more convenient than holding on to the struts for support1 as it will not be necessary to spread the arms so much and there will be more freedom for manipulating the weight to control the glider in flight4 ,in using the struts1 it is customary to grasp them with the hands1 while with the arm pieces1 as the name implies1 the operator places his arms over them1 one of the strips coming under each armpit4 ,after the fabric has been given a coat of varnish on the upper side and allowed to dry1 the glider is ready for use4 ,the cost of the material should be about #cj to #dj1 depending upon the extent to which the builder has relied upon his own ingenuity in fashioning the necessary fittings--in any case1 it will be less than the amount required for the purchase of the engine alone for a power-driven model4 99,glider with ,rudder and ,elevator994 ,it will be noted that this is the simplest possible form of glider in that it is not even provided with a rudder1 but for the beginning of his gliding education the novice will not require this1 as first attempts should be confined to glides over level ground in moderate1 steady wind currents and at a modest elevation4 ,some of the best gliding flights made by ,herring1 ,chanute's co-worker1 were in a rudderless glider4 ,after having mastered the rudiments of the art1 the student may go as far as the dictates of his ambition impel him in the direction of improvements in his glider1 by adding a rudder1 elevator1 and warping control4 ,in fact1 it is not necessary to confine himself to the simple design of glider here outlined at all4 ,he may take either the ,wright or ,curtiss machines as a model and build a complete glider1 following the dimensions and general methods of construction here given1 though these may also be improved upon by the man handy with tools1 bearing in mind that the object to be achieved is the minimum weight consistent with the maximum strength4 99,learning to ,glide994 ,the first trials should be made on level ground and the would-be aviator should be assisted by two companions to help him in getting under way4 ,the operator takes a position in the center rectangle1 back far enough to tilt up slightly the forward edges of the planes4 ,a start and run forward is made at a moderate pace1 the keepers carrying the weight of the glider and overcoming its head resistance by running forward at the same speed4 ,as the glider cuts into the air1 the wind caused by running will catch under the uplifted edges of the curved planes and will buoy it up1 causing it to rise in the air taking the operator with it4 ,this rise will be probably only sufficient to lift him clear of the ground a foot or two4 ,now he projects his legs slightly forward so as to shift the center of gravity a trifle and bring the edges of the glider on an exact level1 parallel with the ground4 ,this1 with the momentum acquired at the start1 will keep the glider moving forward for some distance4 ,when the weight of the operator is slightly back of the center of gravity1 the leading edges of the planes are tilted up somewhat1 increasing the angle of incidence and in consequence the pressure under the planes1 causing the glider to rise1 and if the glide is being made into a wind1 as should always be the case1 quite a height may be reached as the result of this energy4 ,once it ceases1 the tendency to a forward and upward movement is lost1 and it is to prolong this as much as possible that the operator shifts the center of gravity to bring the machine on an even keel1 or where at a little height1 slightly below this1 giving it a negative angle of incidence1 which permits him to coast down the air until sufficient speed is acquired to reverse the angle of incidence and again rise so as to provide a hill for another coast1 thus prolonging the flight considerably4 ,to put it in the simplest language1 when the operator moves backward1 shifting the center of gravity to the rear1 the planes are tilted so that they catch or scoop up the advancing air and rise upon it1 whereas when he moves forward and the planes tilt downward1 this air is spilled out behind and no longer acts as a support1 and the glider coasts1 either until the ground is reached or enough momentum is gained to again mount upon the wind4 ,a comparatively few flights will suffice to make the student proficient in the control of his apparatus by his body movements1 not only as concerns the elevating and depressing of the planes to ascend or descend1 corresponding to the use of the elevator on a power machine1 but also actual steering1 which is accomplished by lateral movement to the left or right4 ,stable equilibrium is one of the chief essentials to successful flight and this can not be maintained in an uncertain1 gusty wind1 especially by the novice4 ,the beginner should certainly not attempt a glide unless the conditions are right4 ,these are a clear1 level space without obstructions such as trees1 and a steady wind not exceeding #ab miles per hour4 ,when a reasonable amount of proficiency has been attained in the handling of the glider over level ground1 the field of practice may be changed to some gentle slope4 ,in starting from this1 it will be found easier to keep the glider afloat1 but the experience at first will prove startling to the amateur1 for as the glider sails away from the top of the slope1 the distance between him and the ground increases so rapidly that he will imagine himself at a tremendous height1 but by preserving the balance and otherwise manipulating his weight in the manner taught by the practice over the level1 a nice flight of much greater distance will be made and the machine will gradually settle down to the ground much farther away from the starting place than was possible in the earlier trials1 this being one of the great advantages of starting from an elevation4 ,there is nothing that will fit the beginner so well for the actual handling of a power machine as a thorough course of gliding flights1 and it is recommended that those who build gliders become proficient in their use before attempting to pilot an aeroplane1 whether of their own make or not4 ,a further step in advance is the actual building of a full-fledged power machine1 and for those who desire a simple and comparatively inexpensive type1 requiring very little work that can not be performed in the home workshop1 a description of the construction of a ,curtiss biplane is given1 while for those who are more ambitious and also have greater financial resources1 the details of the building of a ,bleriot monoplane are given4 ,,building ,a ,,curtiss ,,biplane ,cost4 ,first of all1 the prospective builder will want to know the cost4 ,the best answer to this is that the machine will cost all its builder can afford to spend upon it and probably a little more1 as the man to whom the expense is not of vital consideration will doubtless not undertake its construction4 ,speaking generally1 and there can be nothing very definite about it1 in view of the great difference in the conditions1 an expenditure of three to four hundred dollars will cover the complete outlay for everything but the motor4 ,if the builder has the time and facilities for doing all the work himself1 this amount may be reduced very materially4 ,on the other hand1 if he finds it necessary to purchase most of the material in form ready to assemble1 it may exceed this4 ,but it will be a great aid to many to know that there is practically nothing about the modern aeroplane which can not be found in stock at one of the aeronautic supply houses4 ,this makes it possible for many to undertake the construction of a machine to whom it would not be feasible1 or at least not an attractive project in view of the time involved1 were it necessary to make every part at home4 ,so far as becoming involved in any legal difficulties is concerned owing to existing patents1 the student need not worry himself about this in attempting the construction of a ,curtiss biplane1 so long as he restricts the use of his machine to experimental purposes and does not try to compete with the patentees in their own field--that of exhibiting and selling machines4 ,illustration3 ,fig #aa4 ,detailed ,front ,view of ,curtiss ,biplane 99,general ,specifications994 ,just how long it will take to complete such a machine will depend very largely upon the skill of the builder and the extent of his resources for1 as already mentioned1 the expense may be cut down by making all the necessary parts at home1 but it will naturally be at the sacrifice of a great deal of time4 ,for instance1 the oval struts and beams may be bought already shaped from the local planing mill1 or they may be shaved down from the rough by hand4 ,turnbuckles can be made from bicycle spokes and nipples and strips of sheet steel1 or they can be bought at #ab to #ae cents each4 ,as a hundred or more of them are needed1 their cost is quite a substantial item4 ,illustration3 ,fig #ab4 ,plan and ,side ,elevation of ,curtiss ,biplane ,aeroplane construction doubtless impresses the average observer as being something shrouded in considerable mystery--something about which there is no little secrecy4 ,quite the contrary is the case in reality4 ,any man who is fairly proficient as a carpenter and knows how to use the more common machinist's tools1 such as taps and dies1 drills1 hacksaw1 and the like1 will find no difficulty in constructing the machine of which the details are given here4 ,having completed its building1 he will have to draw upon his capital to supply the motor4 ,one capable of developing #be to #cj horse-power at #a1jjj to #a1bjj r4p4m4 will give the machine considerable speed1 as it will be recalled that ,curtiss made a number of his first flights with a #be-;horse-power motor4 ,as to the weight1 the lighter the better1 but #djj pounds for the complete power plant will not be excessive4 ,the machine can sustain itself in the air with less power than that mentioned1 but with a heavy1 low-power motor it will be sluggish in action4 ,this is an advantage for the amateur1 rather than otherwise1 as it will provide him with an aeroplane that will not be apt to get away from him during his first trials1 thus making it safer to learn on4 ,illustration3 ,fig #ac4 ,details of ,main and ,small ,ribs1 ,curtiss ,biplane ,the ,curtiss biplane has a spread of #cj feet1 the main planes or wings being divided into sections of a length equal to the distance between struts1 ,figs4 #aa and #ab4 ,there are five of these sections1 each measuring six feet4 ,the struts can be taken out and the sections laid flat on each other for storage4 ,the framework for the front and rear rudders can also be jointed1 if desired1 making it possible to store the machine in small compass4 ,the longest parts of the machine1 when taken apart1 are the two diagonal beams running from the front wheel back to the engine bed1 and the skid4 ,the horizontal front rudder is packed intact4 ,the vertical rear rudder is unhung and laid flat on the tail4 ,two men can take the machine apart in a few hours1 and can reassemble it in a day4 ,whether these particular features of construction are covered by patents can not be said1 as ,curtiss has declined to commit himself regarding any rights he may have to them4 ,ribs4 ,two distinct types of ribs are used1 main ribs and small ribs1 both of the same curvature1 ,fig4 #ac4 ,the main ribs are used between pairs of struts1 to hold apart the front and rear beams2 they are heavy enough to be quite rigid4 ,three to four small ribs are laid across each section of the planes1 between the pairs of main ribs1 to give the cloth the proper curvature1 and to maintain it in the form desired4 ,the main ribs are built up of six #a_/d-;inch laminations of wood #g_/h inch wide and securely glued together4 ,the small ribs are made of three layers #a_/b inch wide4 ,the first part of the actual construction will be the making of these laminated ribs1 but before describing this detail1 the question of suitable material should be well considered4 ,both weight and strength must be figured on and this limits the choice to a few kinds of wood4 ,of these spruce and elm are the best available1 with the occasional use of ash to give greater rigidity4 ,spruce is1 of course1 the first choice4 ,this wood was once considered as having no great strength1 but a series of careful tests shows this belief to be unfounded4 ,with the exception of the bed1 or support for the motor and a few other parts1 the ,wright machines are constructed wholly of spruce4 ,table ,i gives results of tests made with spruce from ,washington and ,oregon1 and with elm from ,michigan and ,indiana4 ,testing scales were employed1 the pieces being supported at their ends with the load in the center4 ,these tests were made with clear wood in each case1 as knots naturally decrease the strength of a piece greatly1 this depending on their size and location4 ,illustration3 ,fig4 #ad4 ,details of ,rib ,press1 ,curtiss ,biplane ,before proceeding with the ribs themselves1 the press for giving them the proper curvature must be made4 ,take a good piece of oak1 ash1 or other solid wood1 #h inches wide by #e feet long1 and dressed all over4 ,on the side of the piece lay out the curve1 the dimensions of which are illustrated in ,fig4 #ad4 ,first1 rule the horizontal1 or chord line1 on it1 marking off #d feet #f inches on this line1 equidistant from each end4 ,then divide the chord into #f-;inch sections and1 at the point of each #f-;inch section1 erect perpendiculars beginning at the rear1 #c_/d inch1 #a #c_/h inches1 #b inches1 and so on1 as indicated on the drawing4 ,the upper ends of these perpendiculars will form locating points for the curve4 ,through them draw a smooth curve as shown1 continuing it down through the chord at each end4 ,take the piece with the curve thus marked on it to the local planing1 sash and blind1 or sawmill--any plant equipped with a band saw--and have it cut apart along the curve4 ,this will cost little or nothing--acquaintance will obtain it as a favor1 and acquaintance with any wood-working concern in the aeroplane builder's home town will be of great aid4 ,failing this aid1 the operation may be carried out with a hand saw 7rip71 but the job will not be as neat and will have to be cleaned up with a draw knife and sand paper1 taking care to preserve the outline of the curve as drawn4 ,as the rib press is really a mould or pattern from which all the ribs are to be bent to a uniform curvature1 care must be taken in its construction4 ,to clamp the two halves of the press together1 a dozen machine bolts will be required2 they should measure #c_/d ,x #ae inches4 ,if obtainable1 eye bolts will be found more convenient as they may be turned up with but one wrench and a bar4 ,the steel straps are #c_/h by #a #a_/b by #aj inches long with #c_/d-;inch holes drilled #i inches apart to centers1 to enclose the #h-;inch pieces4 ,obtain a sufficient supply of boards of reasonably clear spruce1 #a_/d inch thick1 #f to #g inches wide1 and at least #d feet #i inches long 7dressed both sides71 to make all the ribs necessary both small and large4 ,this material should be purchased from the mill as it is out of the question to attempt to cut the ribs from larger sizes by hand4 ,buy several pounds of good cabinet makers' glue and a water-jacketed gluepot4 ,this glue comes in sheets and in numerous grades--a good quality should be used1 costing from #dj to #ej cents a pound if bought in a large city4 ,laminating the ribs in this manner and gluing them together is not only the quickest and easiest method of giving them the proper curve1 being much superior to steam bending1 but is also stronger when well done1 as the quality of the material can be watched more closely4 ,start with the making of the small ribs2 apply the glue thin and piping hot in a generous layer to three boards with a good-sized flat paint or varnish brush4 ,omit on the upper surface of third board and apply between three others1 ,fig4 #ac4 ,this will give two series of three each in the press4 ,tighten up the end bolts first1 as the upper part of the press near the top of the curve is likely to be weak unless liberally proportioned4 ,then turn down the nuts on the other bolts4 ,do not attempt to turn any one of them as far as it will go the first time1 but tighten each one a little at a time1 thus gradually making the compression over the whole surface as nearly uniform as possible4 ,this should be continued until the glue will no longer ooze out from between the boards1 indicating that they are in close contact4 ,twenty-four hours should be allowed for drying1 and when taken out the cracks between the boards should be almost invisible in the finished ribs4 ,have the laminated boards cut by a power rip saw at the planing mill1 to the dimensions shown in the drawing1 making an allowance of #a_/d inch for the width of the saw blade at each cut in calculating the number of ribs which can be cut from each board4 ,in addition1 a margin should be allowed at each side1 as it is impractical to get all the thin boards squarely in line4 ,for the main ribs1 apply the glue between all six boards1 clamp and dry in the same manner4 ,thirty small ribs will be required1 if three are used in each section1 and forty if four are specified1 while twelve main ribs will be needed for standard construction1 and sixteen if the quick-demountable plan referred to is followed4 ,it is advisable to make several extra ribs of each kind in addition4 ,if the builder has not sufficient faith in spruce alone1 despite the figures given in ,table ,i1 one of the laminations1 preferably the center1 or if two be employed1 the outer ones1 may be of ash1 though this will add considerably to the weight4 ,to prevent the ribs from splitting open at the ends1 they are protected by light steel ferrules1 shown in ,fig4 #ae4 ,when received in the rough-sawed condition from the mill1 the ribs must be tapered at the ends with a plane or spoke shave to fit these ferrules1 and the sharp edges should be rounded off4 ,in doing this1 it must be remembered that the upper surface of the small ribs gives the curvature to the cloth surface1 so that any tapering must be done on the lower side4 ,the main ribs may be tapered from both sides1 as it is the center line1 or crack between the third and fourth laminations1 that determines the curve4 ,every inch along this line ,a-inch holes are to be drilled for the lacing1 ,fig4 #ae4 ,the ferrules for the front ends of the small ribs are light #a_/b-;inch seamless steel tubing2 they may be flattened to the proper shape in a vise without heating and are drilled with a #a_/h-;inch hole4 ,they are driven tight on to the tapered ends of the ribs and fastened in place with a small screw4 ,the rear-end ferrules are #a_/b-;inch lengths of #c_/h-;inch tubing1 driven on and drilled with a #a_/cb-;inch hole for the rear-edge wire4 ,the rear ferrules of the main ribs may be the same #a_/b-;inch tubing used for the front of the small ribs2 they should be cut off so that their ends will come in the same line as the holes in the ends of the small ribs4 ,if the quick-demountable plan be followed1 the second main rib from each end may be left long and drilled with a hole like the small ribs4 ,the front ferrules of the main ribs should be #c_/d-;inch tubing of heavier gauge1 drilled with a #a_/d-;inch hole4 ,the finished ribs are sandpapered smooth and shellaced or coated with spar varnish4 ,the latter is much more expensive and slower in drying but has the great advantage of being weather-proof and will protect the glue cracks from moisture4 ,the ferrules may be painted with black enamel4 ,illustration3 ,fig4 #ae4 ,details of ,ribs and ,struts1 ,curtiss ,biplane ,struts4 ,before going into the detail of the construction of the remainder of the main cell and its attached framing1 a brief description of its parts and their relation to one another will make matters clearer4 ,the upright struts1 ,fig4 #ae1 which hold the two planes apart1 fit at each end into sockets1 which are simply metal cups with bolts projecting through their ends4 ,fig4 #af4 ,those at the bottom of the front row of struts pass through the eyes of the turnbuckles and connections for the wire trussing1 then through the flattened ferrules of the main ribs1 and finally through the beam1 all being clamped together with a nut4 ,those at the top go through the turnbuckles first1 then through the beam1 and finally the rib ferrule4 ,the bolts at the back row of struts must go through the full thickness of the main ribs1 and so must be longer4 ,the drawings4 ,figs4 #ae and #af1 show the method of attachment of both the main and the small ribs and illustrate a neat method of attaching the turnbuckles--instead of being strung on the socket bolt one after another1 they are riveted to the corners of a steel plate which alone is clamped under the socket4 ,illustration3 ,fig4 #af4 ,details of ,metal ,parts of ,curtiss ,biplane ,beams4 ,the beams are jointed at each strut connection1 the ends being cut square and united by a sheet-steel sleeve1 a pattern of which is shown in ,fig4 #af1 clamped on by two small bolts4 ,the hole for the socket bolt is drilled half in each of the two abutting beams4 ,as it is very difficult to obtain long pieces of wood sufficiently straight grained and free from knots for the purpose1 this jointed system considerably cheapens the construction4 ,both beams and struts are of spruce1 but to give additional strength1 the beams of the middle section may be ash4 ,special aero cloth1 rubberized fabrics1 or light1 closely-woven duck 7racing yacht sail cloth of fine quality1 this being employed at first by the ,wright ,brothers in their machines7 forms the surfaces of the wings4 ,the front edge of each section of the surface is tacked to the beam and the rear edge is laced over the rear wire already referred to1 this wire being stretched taut through the holes in the rear tips of the ribs1 both main and small4 ,after the cloth is stretched tight1 it is tacked to the small ribs1 a strip of tape being laid under the tack heads to prevent the cloth from pulling away from under them4 ,if the aeroplane is intended to be taken apart very often1 the standard design as shown by the large drawings1 ,figs4 #aa and #ab1 may be modified so as to make it unnecessary to unlace the cloth each time4 ,this is arranged by regarding the two outer sections at each end of the plane as one1 and never separating them4 ,additional main ribs are then provided at the inner ends of these sections1 and are attached directly to the beams1 instead of being clamped under the strut sockets4 ,in taking the machine apart1 the struts are pulled from the sockets1 leaving the latter in place4 ,it will then be an advantage to shorten the main planes somewhat1 say #c inches on each section1 so that the outer double sections will come under the #ab-;foot rule of the ,express ,companies4 ,running ,gear4 ,three wheels are provided--one in front under the outrigger and two under the main cell for starting and landing4 ,two beams extend from the front wheel to the engine bed and serve to carry the pilot's seat1 as will be seen from the elevator1 ,fig4 #ab4 ,a third beam runs back horizontally from the front wheel and on rough ground acts as a skid4 ,the rest of the running gear is made of steel tubing1 the pieces being joined simply by flattening the ends1 drilling and clamping with bolts2 no sockets or special connections of any kind are necessary here4 ,if desired1 the wheels may be carried in bicycle forks and may be fitted with shock absorbers1 some idea of the various expedients adopted by different builders for this purpose being obtainable from the sketches4 ,fig4 #dj in ,types of ,aeroplanes4 ,two separate tubes1 one on each side of the wheel make a simple construction and will probably serve just as well4 ,the details of the running gear will be given later4 ,outrigging and ,rudders4 ,for the outriggers and the frames carrying the front horizontal or elevating rudder and the rear vertical rudder and tail1 or horizontal keel1 either spruce or bamboo may be employed4 ,bamboo will be found on machines turned out by the ,curtiss factory1 and while it is the lighter of the two1 it is not generally favored1 as spruce is easier to obtain in good quality and is far easier to work4 ,at their ends1 these outriggers are fitted with ferrules of steel tubing1 flattened and drilled through4 ,the outriggers are attached to the main framework of the machine by slipping the ferrules over the socket bolts of the middle section struts1 above and below the beams4 ,it is preferable1 however1 to attach the rear outriggers to extra bolts running through the beams1 so that when the machine is to be housed the tail and rudder can be unshipped and the triangular frames swung around against the main frame1 considerably reducing the space required4 ,the tail1 horizontal and vertical rudders1 and the ailerons are light frames of wood1 covered on both sides with the same kind of cloth as the main planes or wings4 ,these frames are braced with piano wire in such a manner that no twisting strains can be put on them4 ,the front horizontal rudder1 which is of biplane construction like the main cell1 is built up with struts in the same way4 ,instead of being fitted with sockets1 however1 the struts are held by long screws run through the planes and into their ends1 passing through the eyes of the turnbuckles4 ,,details ,,of ,,construction 99,main ,planes and ,struts994 ,it is preferable to begin with the construction of the main planes and their struts and truss wires1 the ribs already described being the first step4 ,the main beams offer no special difficulties4 ,they are ovals #a #a_/d by #a #e_/h inches1 all #f feet long except the eight end ones1 which are #f feet #b inches4 ,the beams of the central section should be of ash1 or should be thicker than the others4 ,in the latter case1 they must be tapered at the ends so that the clamping sleeves will fit and the additional wood must be all on the lower side1 so that the rib will not be thrown out of alignment4 ,the spruce used for the other beams should be reasonably clear and straight grained1 but a small knot or two does not matter1 provided it does not come near the ends of the beam4 ,the beams may be cut to the oval shape by the sawmill or planed down by hand4 ,fish-shaped or stream-line section1 as it is more commonly termed1 is used for the struts1 ,fig4 #ae4 ,it is questionable whether this makes any material difference in the wind resistance1 but it is common practice to follow it in order to minimize this factor4 ,it is more important that the struts be larger at their centers than at the ends1 as this strengthens them considerably4 ,at their ends the struts have ferrules of the #a-;inch brass or steel tubing1 and fit into the sockets which clamp the ribs and beams together4 ,the material is spruce but the four central struts which carry the engine bed should either be ash or of larger size1 say #a #a_/d by #c inches4 ,care ,necessary to ,get ,planes ,parallel4 ,the front struts must be longer than the rear ones by the thickness of a main rib at the point where the rear strut bolt passes through it1 less the thickness of the rib ferrule through which the bolt of the front strut must pass4 ,however1 the first distance is not really the actual thickness of the rib1 but the distance between the top of the rear beam and the bottom of the strut socket4 ,in the drawings the difference in length between the front and rear struts is given as #b inches1 but it is preferable for the builder to leave the rear struts rather long and then measure the actual distance when assembling1 cutting the struts to fit4 ,the ends of the struts should also be countersunk enough to clear the head of the socket bolt4 ,one of the items which the builder can not well escape buying in finished form is the strut sockets4 ,these are cup-shaped affairs of pressed steel which sell at #bj cents each4 ,sixteen of them will be required for the main frame1 and a dozen more can advantageously be used in the front and rear controls1 though for this purpose they are not absolutely necessary4 ,they can also be obtained in a larger oval size suitable for the four central struts that carry the engine bed1 as well as in the standard #a-;inch size4 ,the bolts which project through the bottom of the sockets are ordinary #a_/d-;inch stove bolts1 with their heads brazed to the sockets4 ,for the rear struts1 where the bolt must pass through the slanting main rib1 it is advisable to make angle washers to put under the socket and also between the beam and rib4 ,these washers are made by sawing up a piece of heavy brass tubing1 or a bar with a #a_/d-;inch hole drilled in its center1 the saw cuts being taken alternately at right angles and at #fj degrees to the axis of the tube4 ,the sleeves which clamp together the ends of the beams are made of sheet steel of about #bj gauge4 ,the steel is cut out on the pattern given in the drawing1 ,fig4 #af1 and the #c_/af-;inch bolt holes drilled in the flanges4 ,the flanges are bent over by clamping the sheet in a vise along the bending line and then beating down with a hammer4 ,then the sleeves can be bent into shape around a stray end of the beam wood4 ,the holes for the strut socket bolts should not be drilled until ready to assemble4 ,ordinarily1 #c_/af-;inch stove bolts will do to clamp the flanges together4 ,having reached this stage1 the amateur builder must now supply himself with turnbuckles4 ,as already mentioned1 these may either be purchased or made by hand4 ,it is permissible to use either one or two turnbuckles on each wire4 ,one is really sufficient1 but two--one at each end--add but little weight and give greater leeway in making adjustments4 ,as there are about #aae wires in the machine which need turnbuckles1 the number required will be either #aae or #bcj1 depending upon the plan which is followed4 ,those of the turnbuckles to be used on the front and rear controls and the ailerons1 about one-fifth of the total number1 may be of lighter stock than those employed on wires which carry part of the weight of the machine4 99,making ,turnbuckles for the ,truss ,wires994 ,on the supposition that the builder will make his own turnbuckles1 a simple form is described here4 ,as will be seen from ,fig4 #af1 the turnbuckles are simply bicycle spokes1 with the nipple caught in a loop of sheet steel and the end of the spoke itself twisted into an eye to which the truss wire can be attached4 ,the sheet steel used should be #ah or #af gauge1 and may be cut to pattern with a heavy pair of tin snips4 ,the spokes should be #c_/cb inch over the threaded portion4 ,the eye should be twisted up tight and brazed so that it can not come apart4 ,the hole in the middle of each strip is1 of course1 drilled the same size as the spoke nipple4 ,the holes in the ends are #c_/af inch4 ,in the original ,curtiss machines1 the turnbuckles were strung on the socket bolts one after another1 sometimes making a pack of them half an inch thick4 ,a much neater construction is shown in the drawings1 in which the bolt pierces a single plate with lugs to which to make the turnbuckles fast by riveting4 ,the plates are of different shapes1 with two1 three1 or four lugs1 according to the places where they are to be used4 ,they are cut from steel stock #c_/cb inch thick1 with #a_/d-;inch holes for the socket bolts and #c_/af inch1 or other convenient size1 for the rivets that fasten on the turnbuckles4 ,the relative merits of cable and piano wire for trussing have not been thoroughly threshed out4 ,each has its advantages and disadvantages4 ,most of the well-known builders use cable2 yet if the difference between #a1jjj feet of cable at #b #a_/d cents per foot 7the price for #ejj-;foot spools71 and #h pounds of piano wire at #gj cents a pound1 looks considerable to the amateur builder1 let him by all means use the wire4 ,the cable1 if used1 should be the #c_/cb-;inch size1 which will stand a load of #hjj pounds2 piano wire should be #bd gauge1 tested to #gde pounds4 ,it should be noted that there is a special series of gauges for piano wire1 known as the music wire gauge1 in which the size of the wire increases with the gauge numbers1 instead of the contrary1 as is usual with machinery wire gauges4 ,one by no means unimportant advantage of the piano wire is that it is much easier to fasten into the turnbuckles4 ,a small sleeve or ferrule1 a #a_/d-;inch length of #a_/h-;inch tubing1 is first strung on the wire4 ,the end of the wire is then passed through the turnbuckle eye1 bent up1 thrust through the sleeve1 and again bent down4 ,when the machine is taken apart1 the wire is not disconnected from the eye1 but instead the turnbuckle spoke is unscrewed from the nipple4 ,the shape of the sheet-steel loop should be such as to hold the latter in place4 ,cable1 on the other hand1 must be cut with about #b inches to spare4 ,after being threaded through the turnbuckle eye1 the end is wound back tightly on itself and then soldered1 to make certain that it can not loosen4 ,with a supply of turnbuckles and cable or piano wire at hand1 the builder may go ahead with the main box-like structure or cell1 which should be completed except for the cloth covering1 and in proper alignment1 before taking up the construction of the running gear and controls4 99,running ,gear994 ,the running gear of the machine is built of seamless steel tubing1 those parts which carry the weight of the machine direct being of #c_/d-;inch outside diameter1 #af-;gauge tubing1 while the others are #e_/h-;inch outside diameter1 either #ah or #bj gauge4 ,about #be feet of the heavy and #de feet of the light tubing will be required1 in lengths as follows3 ,heavy1 four #c-;foot1 three #d-;foot2 light1 one #f-;foot1 two #d-;foot #f-;inch1 and seven #d-;foot pieces4 ,referring to ,fig4 #ag1 two diagonal braces from the rear beam to the engine bed1 the ,v-shaped piece under the front engine bed struts and all of the rear frame except the horizontal piece from wheel to wheel1 are of heavy tubing4 ,the horizontal in the rear frame1 diagonals from the rear wheels and the rear end of the skid to the front beam1 the two horizontals between the front and rear beam1 and the forward ,v are of light tubing4 ,illustration3 ,fig4 #ag4 ,details of ,curtiss ,running ,gear ,three ash beams are used in the running gear4 ,two of these run diagonally from the rear end of the engine bed to the front wheel4 ,these are about #aj feet long and #a by #a #c_/d inches section4 ,the third1 which on rough ground acts as a skid1 is #h #a_/b feet long and about #b inches square4 ,between the joints where the tubing frames are attached to it1 the upper corners may be beveled off with a spoke shave an inch or more down each side4 ,the beams are attached to the front wheel with strips of steel stock #a #a_/b inches wide and #a_/h inch thick4 ,the engine bed beams are also ash about #a by #a #c_/d inches section4 ,their rear ends are bolted to the middle of the rear engine bed struts and the front ends may be #a_/b inch higher4 ,illustration3 ,,scene ,,at ,,aviation ,,meet ,,at ,,rouen1 ,,france1 ,,showing ,,an ,,antoinette ,,monoplane ,,making ,a ,,turn ,this ,photograph ,protected ,by ,international ,copyright ,illustration3 ,a ,,french ,,monoplane ,,travelling ,,sixty-,,five ,,miles ,,an ,,hour ,this ,photograph ,protected ,by ,international ,copyright ,the wheels are usually #bj by #b inches1 and of the bicycle type1 but heavier and wider in the hub2 the tires are single tube4 ,these wheels1 complete with tires1 cost about #aj each4 ,this size is used on the standard ,curtiss machines1 but novice operators1 whose landings are not quite as gentle as they might be1 find them easily broken4 ,therefore1 it may be more economical in the end to pay a little more and get heavier tires--at least to start with4 ,for working the tubing into shape1 a plumber's blow torch is almost indispensable--most automobilists will already possess one of these4 ,the oval1 flat variety1 holding about one pint1 is very handy and packs away easily1 but on steady work requires filling somewhat too frequently4 ,with a dozen bricks a shield can be built in front of the torch to protect the flame and concentrate the heat4 ,whenever it is to be flattened and bent1 the tubing should be brought to a bright red or yellow heat4 ,screwing the vise down on it will then flatten it quickly without hammer marks4 ,where the bend is to be made in the middle of the piece1 however1 it may be necessary to resort to the hammer and anvil4 ,it is convenient to start with the framework under the rear beam4 ,this may be drawn accurately to full size on the workshop floor1 and the tubes bent to fit the drawing4 ,with this framework once in place1 a definite starting point for the remainder of the running gear is established4 ,here and in all other places1 when boring through wood1 the holes should be drilled out full1 and larger washers should be placed under the bolt head and nut4 ,all nuts should be provided with some sort of locking device ,the perspective drawing4 ,fig4 #ag1 should show the general arrangement clearly enough to enable the builder to finish the running gear4 99,outriggers994 ,both the front and rear control members1 or outriggers as they are termed1 ,fig4 #ab1 may be conveniently built up on the central section of the main frame1 which1 it is assumed1 has now been fitted with the running gear4 ,the horizontal rudder1 or elevator1 is a biplane structure like the main cell of the machine1 but with fewer struts2 it is carried in front of the main planes on two 99,a99-shaped frames4 ,the vertical rudder1 at the rear1 is split along the middle and straddles a fixed horizontal plane1 or tail4 ,this also is carried on two 99,a99-shaped frames4 ,lateral stability is controlled by two auxiliary planes or ailerons1 one at each side of the machine and carried on the two outer front struts4 ,these three control units--elevator1 tail and rudder1 and ailerons--will now be taken up separately and their construction1 location on the machine1 and operation will be described4 ,illustration3 ,fig4 #ah4 ,details of ,rudders and ,ailerons1 ,curtiss ,biplane ,horizonal ,rudder or ,elevator4 ,the two planes of the elevator are #b feet wide by #e feet #h inches long and are spaced #b feet apart1 being held in this position by ten struts4 ,the frames of the planes are built of spruce sticks #a_/b by #a inch1 each plane having two sticks the full length and five evenly spaced crosspieces or ribs4 ,these are joined together with squares of ,x-sheet tin1 as shown in the detailed drawing1 ,fig4 #ah4 ,with a little experimenting1 paper patterns can be made from which the tin pieces can be cut out4 ,the sticks are then nailed through the tin with #c_/d-;inch brads4 ,it is convenient to draw the frames out accurately on a smooth wood floor and then work over this drawing4 ,the first few brads will hold the sticks in place4 ,when all the brads have been driven1 a little drop of solder should be run in around the head of each one4 ,this is a tedious job4 ,one must be careful to use no more solder than necessary as it increases the weight very rapidly4 ,two pounds of wire solder should be sufficient for all the control members which are built in this way4 ,when the top side is soldered1 pry the frame loose from the floor with a screwdriver and turn it over4 ,then the projecting points of the brads must be clinched and the soldering repeated4 ,at this stage1 the two frames should be covered on both sides with the prepared cloth used for covering the main planes4 ,the method of preparing this cloth is detailed a little farther along4 ,the struts1 so-called1 to continue the analogy with the main planes1 are turned sticks of spruce #c_/h inch in diameter4 ,they are fitted at each end with ferrules of thin #c_/h-;inch brass1 or steel tubing1 driven on tight4 ,instead of using sockets1 the struts are held at each end1 simply by a long wood screw driven through the tin and wood of the plane frame and into the strut4 ,these screws also hold the turnbuckles for the truss wires4 ,for trussing purposes1 the elevator is regarded as consisting of two sections only1 the intermediate struts being disregarded4 ,the turnbuckles and wire used here and in the other control members may well be of lighter stock than those used in the main planes4 ,piano wire1 ,no4 #ah1 or #a_/af-;inch cable is amply strong4 ,the sheet steel may be about #bb gauge1 instead of #af1 and the bicycle spokes smaller in proportion4 ,no turnbuckle plates are necessary4 ,the screws running into the struts may be passed directly through the eyes of the turnbuckles1 where they would have been attached to the turnbuckle plate4 ,in order to secure a square and neat structure1 those struts which have turnbuckles at their ends should be made a trifle shorter than the others4 ,at each end1 the elevator has an 99,x99-shaped frame of #a_/d-;inch steel tubing2 at the intersection of the 99,x99's are pivots on which the elevator is supported4 ,each 99,x99 is made of two tubes1 bent into a y and flattened and brazed together at the points4 ,the ends of the 99,x99's are flattened and bent over so that the screws which hold the struts in place may pass through them4 ,illustration3 ,fig4 #ai4 ,curtiss ,biplane ,ready for ,flight ,to the front middle strut is attached an extension which acts as a lever for operating the elevator4 ,this is a stick of spruce #c_/d inch in diameter and #c feet #c inches long4 ,at its upper end it has a ferrule of steel tubing1 flattened at the end4 ,the lower part of the stick may be fastened to the strut by wrapping the tube with friction tape1 or by improvising a couple of sheet steel clamps4 ,the upper end of the stick is braced by a #a_/d-;inch steel tube1 extending to the top of the rear middle strut1 and held by the same screw as the strut4 ,this extension lever is connected to the steering column by a bamboo rod1 #a inch in diameter and about #aj feet long1 provided with flattened ferrules of steel tubing at each end4 ,each ferrule should be held on by a #a_/h-;inch stove bolt passing through it4 ,front and ,rear ,outrigger ,frames4 ,both the front elevator and the tail and rudder at the rear1 are carried1 as mentioned above1 each on a pair of 99,a99-shaped frames1 similar to one another1 except that those in the rear are longer than those in the front4 ,both are made of spruce of about the same section as used for the struts of the main frame4 ,these pieces may either be full length1 or they may be jointed at the intersection of the crosspieces1 the ends being clamped in a sheet-steel sleeve1 just like that used on the beams of the main frame4 ,in this case1 it is advisable to run a #a_/h-;inch stove bolt through each of the ends4 ,illustration3 ,fig4 #bj4 ,details of ,outriggers and ,front ,elevating ,planes as ,seen from ,driver's ,seat ,the crosspieces of the 99,a99-frames are spruce of the same section1 or a little smaller4 ,at their ends may be used strut sockets like those of the main frame2 or1 if it is desired to save this expense1 they may be fastened by strips of #a_/af-;inch steel stock with through bolts4 ,the front outrigger has1 besides the two ,a-frames1 a rather complicated arrangement of struts designed to brace the front wheel against the shocks of landing4 ,this arrangement does not appear very plain in a plan or elevation1 and may best be understood by reference to the photograph1 ,fig4 #ai1 and the perspective drawing1 ,fig4 #bj4 ,fig4 #bj is a view from the driver's seat4 ,the elevator is seen in front1 the 99,a99-frames at each side1 and at the bottom the two diagonal beams to the engine bed and the skid4 ,reference to this drawing will show the two diagonals run from the front wheel up and back to the top of the main frame1 and two more from the wheel forward to the short crosspieces near the apexes of the 99,a99-frame3 there is also a vertical strut which intersects two horizontal pieces running between the ends of the longer crosspieces of the 99,a99-frames4 ,altogether1 there are five attachments on each side of the front wheel1 through which the axle bolt must pass1 viz1 the connections to the skid1 to one of the diagonals to the engine bed1 to one of the rear diagonals1 to one of the front diagonals1 and to one side of the fork carrying the vertical strut4 ,of these the skid attachments should be on the inside closest to the wheel1 and the engine bed diagonals next4 ,the four additional diagonals running to the front wheel may be spruce of the same section used in the 99,a99-frames1 or turned one inch round4 ,at each end they have flattened ferrules of steel tubing4 ,the beams of the 99,a99-frames have similar ferrules at the ends where they attach to the main frames4 ,these attachments should be made on the socket bolts of the struts on either side of the middle #f-;foot section and on the outer side of the main beams--not between the beam and the socket itself4 ,it is possible1 of course1 to make all the 99,a99-frames and diagonal braces of bamboo1 if desired1 the qualities of this material already having been referred to4 ,bamboo rods for this purpose should be between #a and #a #a_/d inches in diameter4 ,where ferrules are fitted on the ends1 the hole of the bamboo should be plugged with wood glued in place4 ,generally1 in the construction of the outrigger frames1 the builder can use his own discretion to a considerable extent4 ,there tire innumerable details which can be varied--far too many to consider even a part of the possibilities in this connection4 ,if the builder runs across any detail which he does not see mentioned here1 he may safely assume that any workmanlike job will suffice4 ,often1 the method may be adapted to the materials on hand4 ,the diagonal wires from the crosspieces of the ,a-frames to the struts should be crossed4 ,rudder and ,tail ,construction4 ,the frame for the rudder and tail are constructed in much the same way as those for the elevator1 ,fig4 #ah4 ,spruce sticks #a by #a_/b inch are used throughout1 except for the piece at the back edge of the rudder and the long middle piece across the tail2 these should be #a #a_/b by #a_/b inch4 ,this long middle piece of the tail is laid across on top of the rest of the framework4 ,when the cloth is put on1 this makes the upper surface slightly convex while the lower surface remains flat4 ,the ends of this piece should be reinforced with sheet steel1 fairly heavy and drilled for #a_/d-;inch bolts1 attaching the tail to the 99,a99-frames4 ,the rudder is hung from two posts extending above and below the tail4 ,these posts may be set in cast aluminum sockets1 such as may be obtained from any supply house for #bj cents apiece4 ,the posts need not be more than #c_/d inch in diameter4 ,at their outer ends1 they should have ferrules of steel tubing1 and the turnbuckles or other attachments for the truss wires should be attached by a wood screw running into the end of each4 ,from these posts the rudder may be hung on any light hinges the builder may find convenient1 or on hinges improvised from screw eyes or eye bolts1 with a bolt passing through the eyes of each4 ,in steering1 the rudder is controlled by a steering wheel carried on a hinged post in front of the pilot4 ,this post should be ash about #a by #a #a_/d inches4 ,it hinges at the bottom on a steel tube of #a_/b-;inch diameter which passes through it and is supported at the ends on diagonal beams to the engine bed4 ,two diagonals of lighter tubing may be put in to hold the posts centered between the two beams4 ,the post is1 of course1 upright1 and the hub of the wheel is horizontal4 ,the wheel may be conveniently mounted on a piece of tubing of the same size as the hub hole1 run through the post and held by a comparatively small bolt1 which passes through it and has a big washer on either end4 ,the wheel is preferably of the motor-boat variety with a groove around the rim for the steering cable4 ,the rear edge of the tail should be about #a inch lower than the front4 ,to make the rudder post stand approximately vertical1 wedge-shaped pieces of wood may be set under the sockets4 ,the steering connections should be of flexible cables of steel such as are made for this purpose4 ,there should be a double pulley on the post just under the wheel1 and the cables should be led off the post just at the hinge at the bottom1 so that swinging the post will not affect them4 ,the cable is then carried under the lower main plane and out the lower beams of the 99,a99-frames4 ,it is attached to the rudder at the back edge2 snap hooks should be used for easy disconnection in packing4 ,perhaps the best way of guiding the cable1 instead of using pulleys1 is to run it through short pieces of tubing lashed to the beams with friction tape4 ,the tubing can be bent without flattening by first filling it with melted lead1 which1 after the bending1 can be melted out again4 99,ailerons for ,lateral ,stability994 ,the framework of the ailerons is made in the same way as that for the elevator1 tail1 and rudder1 ,fig4 #ah4 ,the pieces around the edges should be #a #a_/b by #a_/b inch1 as also the long strip laid over the top of the ribs4 ,the ribs should be #a_/b by #c_/d inch4 ,each aileron has two holes1 one for the strut to pass through1 and the other for the diagonal truss wires at their intersection4 ,the back edge also has a notch in it to clear the fore and aft wires4 ,each aileron is hung on four strips of soft steel about #a_/b by #c_/af inch1 twisted so that one end is at right angles to the other4 ,these are arranged one on each side of the strut which passes through the aileron1 and one at each end4 ,bolts through the struts carry three of them and the outer one is trussed by wires to each end of the outer strut4 ,a frame of #a_/d-;inch steel tubing fits around the aviator's shoulders and is hinged to the seat1 so that he can move it by leaning from one side to the other4 ,this is connected by flexible cable to the rear edges of the ailerons1 so that when the aviator leans to the left1 he will raise the left and lower the right aileron4 ,the upper edges of the ailerons are directly connected to each other by a cable running along the upper front beam1 so that they must always move together4 99,covering of the ,planes994 ,mention has already been made of the fact1 in the general description of the machine1 that light sail cloth1 as employed on the ,wright machines1 may be used for the planes or wings4 ,as a matter of fact1 many different materials may be successfully employed1 the selection depending upon the builder himself and his financial resources4 ,about #ee square yards of material will be required1 and in comparing prices always compare the width as this may vary from #bh to #ee inches4 ,rubberized silk which is used on the standard ,curtiss machines is the most expensive covering1 its cost running up to something like two hundred dollars4 ,there are also several good aero fabrics on the market which sell at #fj cents a square yard1 as well as a number of brands of varnish for the cloth--most of them1 however1 quite expensive4 ,the most economical method is to employ a strong linen cloth coated with shellac1 which will be found very satisfactory4 ,the covering of the frames with the cloth may well be postponed until after the engine has been installed and tested1 thus avoiding the splashing of oil and dirt which the fabric is apt to receive during this operation4 ,the wire to which the cloth is laced1 must be strung along the rear ends of the ribs of each plane4 ,the wires pass through holes in the ends of the small ribs and are attached to the main ribs with turnbuckles4 ,at the ends of the planes the main ribs must be braced against the pull of the wire by a piece of #a_/d-;inch tubing running from the end of the rib diagonally up to the rear beam4 ,both turnbuckles and tube are fastened with one wood screw running into the end of the rib4 ,the cloth should be cut to fit the panels between the main ribs and hemmed up1 allowing at least an inch in each direction for stretch4 ,small eyelets should be put along the sides and rear edges an inch apart for the lacing4 ,at the front edge1 the cloth is tacked directly to the beam1 the edge being taken well under and around to the back4 ,strong fish line is good material for the lacing4 ,after the cloth is laced on1 it must be tacked down to the small ribs4 ,for this purpose1 use upholstery tacks as they have big cup-shaped heads which grip the cloth and do not tear out4 ,as an extra precaution a strip of heavy tape must be run over each rib under the tack heads4 ,all the control members are covered on both sides1 the edges being folded under and held by tacks4 99,making the ,propeller994 ,if the completed biplane is to fly properly and also have sufficient speed to make it safe1 considerable care must be devoted to the design and making of the propeller4 ,every aeroplane has a safe speed1 usually referred to in technical parlance as its critical speed4 ,in the case of the ,curtiss biplane under consideration1 this speed is about #dj miles an hour4 ,by speeding up the motor considerably1 it may be able to make #db to #dc miles an hour in a calm1 such a condition representing the only true measure of an aeroplane's ability in this direction1 while on the other hand1 it would not be safe to let its speed with relation to the wind 7not to the ground7 fall much below #ce miles an hour4 ,at any slower rate of travel1 its dynamic stability would be precarious and the machine would be likely to dive to the ground unexpectedly4 ,the reasons for this have been explained more in detail under the heading of ,the ,internal ,work of the ,wind4 ,the necessity of making the propeller need not discourage the ambitious builder--if he can spare the time to do it right1 it will be excellent experience4 ,if not1 propellers designed for driving a machine of this size can be purchased ready to mount from any one of quite a number of manufacturers4 ,but as the outlay required will be at least #ej1 doubtless most experimenters will prefer to undertake this part of the work as well as that of building the framework and main cell1 particularly as more than #ij per cent of the sum mentioned is represented by labor4 ,the cost of the material required is insignificant by comparison4 ,true-,screw ,design4 ,first it will be necessary to design the propeller to meet the requirements of the biplane itself4 ,as this is a matter that has already been gone into in considerable detail under the appropriate heading1 no further explanation of propeller characteristics or of the technical terms employed1 should be needed here4 ,we will assume that the biplane is to have a speed of #dj miles per hour in still air with the motor running at #a1bjj r4p4m4 ,with this data1 it will not be difficult to calculate the correct pitch of the propeller to give that result4 ,thus #dj ,x #e1bhj ,x #ajj _/ #fj ,x #a1bjj ,x #he #c4de or in round numbers a pitch of #c #a_/b feet4 #dj 7the speed in miles per hour7 times #e1bhj 7feet per mile7 divided by #jj 7minutes in an hour7 gives the speed of the aeroplane in feet per minute4 ,dividing this by #a1bjj 7revolutions per minute7 gives the number of feet the aeroplane is to advance per revolution of the propeller4 ,the #ajj_/he part of the equation represents the efficiency of the propeller which can safely be figured on1 i4e41 #he per cent1 or an allowance for slip of #ae per cent4 ,forty miles an hour is the maximum speed to be expected1 while the r4p4m4 rate of the engine should be that at which it operates to the best advantage4 ,the merits of the true-screw and variable-pitch propellers have already been dwelt upon4 ,the former is not only more simple to build1 but experience has shown that1 as generally employed1 it gives better efficiency4 ,hence1 the propeller under consideration will1 be of the true-screw type4 ,its pitch has already been calculated as #c #a_/b feet4 ,for a machine of this size and power1 it should be #f feet in diameter4 ,having worked out the pitch and decided upon the diameter1 the next and most important thing is to calculate the pitch angle4 ,it will be evident that no two points on the blade will travel through the air at the same speed4 ,obviously1 a point near the tip of the propeller moves faster than one near the hub1 just as in rounding a curve1 the outer wheel of an automobile has to travel faster than the inner1 because it has to travel farther to cover the same ground4 ,for instance1 taking the dimensions of the propeller in question it will be seen that its tips will be traveling through the air at close to #d4c miles per minute1 that is1 #f ,x ,x #abjj _/ #e1bhj #d4bh in which #f1 the diameter of the propeller in feet1 times gives the circumference of the circle which is traveled by the blade tips #a1bjj times per minute2 this divided by the number of feet per mile gives the miles per minute covered4 ,on the other hand1 a point on the blade but #f inches from the hub will turn at only approximately #c1ejj feet per minute4 ,therefore1 if every part of the blade is to advance through the air equally1 the inner part must be set at a greater angle than the outer part4 ,each part of the blade must be set at such an angle that at each revolution it will move forward through the air a distance equal to the pitch4 ,this is known as the pitch angle4 ,the pitch divided by the circumference of the circle described by any part of the blade1 will give a quantity known as the tangent of an angle for that particular part4 ,the angle corresponding to that tangent may most easily be found by referring to a book of trigonometric tables4 ,for example1 take that part of the blade of a #c #a_/b-;foot pitch propeller which is #f inches from the center of the hub4 ,then #c4e ,x #ab _/ #f ,x #b #a4aada tangent of #dh degrees #e minutes in which #c4e ,x #ab reduces the pitch to inches1 while #f ,x #b is the circumference of the circle described by the point #f inches from the hub4 ,however1 in order to give the propeller blade a proper hold on the air1 it must be set at a greater angle than these figures would indicate4 ,that is1 it must be given an angle of incidence similar to that given to every one of the supporting planes of the machine4 ,this additional angle ranges from #b degrees #cj minutes1 to #d degrees1 depending upon the speed at which the particular part of the blade travels2 the greater the speed1 the less the angle4 ,this does not apply to that part of the blade near the hub as the latter is depended upon solely for strength and is not expected to add to the effective thrust of the propeller4 ,table ,,ii shows the complete set of figures for a blade of #c #a_/b-;foot pitch1 the angles being worked out for sections of the blade #c inches apart4 ,these angles are employed in ,fig4 #ba1 which shows one blade of the propeller and its cross sections4 ,it should be understood that these calculations apply only to the type of propeller known as the true screw1 as distinguished from the variable pitch4 ,the design of the latter is a matter of personal skill and experience in its making which is hardly capable of expression in any mathematical formula4 ,there are said to be only about three men in this country who know how to make a proper variable-pitch propeller1 and it naturally is without advantage when made otherwise4 ,illustration3 ,fig4 #ba4 ,details of ,propeller ,construction1 ,curtiss ,biplane ,shaping the ,blades4 ,like the ribs1 the propeller is made up of a number of laminations of boards finished true and securely glued1 afterward being cut to the proper shape1 though this process1 of course1 involves far more skill than in the former case4 ,spruce is the strongest wood for its weight1 but it is soft and cracks easily4 ,maple1 on the other hand1 is tough and hard1 so that it will be an advantage to alternate the layers of these woods with an extra maple board1 in order to make both outside strips of the harder wood1 so as to form a good backing for the steel flanges at the hub1 the rear layer extending the full length of the thin rear edges of the blades4 ,other woods may be employed and frequently are used by propeller manufacturers1 such as mahogany 7not the grained wood used for furniture1 but a cheaper grade which is much stronger71 walnut1 alternate spruce and whitewood1 and others4 ,the boards should be selected with the greatest care so as to insure their being perfectly clear1 i4e41 absolutely free of knots1 cross-grained streaks1 or similar flaws1 which would impair their strength and render them difficult to work smoothly4 ,they should measure #f inches wide by #f feet #a inch in length4 ,their surfaces must be finished perfectly true1 so that they will come together uniformly all over the area on which they bear on one another1 and the various pieces must be glued together with the most painstaking care4 ,have the glue hot1 so that it will spread evenly1 and see that it is of a uniform consistency1 in order that it may be smoothly applied to every bit of the surface4 ,they must then be clamped together under as much pressure as it is possible to apply to them with the means at hand1 the rib press already described in detail forming an excellent tool for this purpose4 ,tighten up the nuts evenly a little at a time1 avoiding the application of excessive or uneven pressure at one point1 continuing the gradual tightening up process until it can not be carried any farther4 ,this is to prevent the boards from assuming a curve in drying fast4 ,allow at least twenty-four hours for drying1 during which period the laminated block should be kept in a cool1 dry place at as even a temperature as possible4 ,before undertaking the remainder of the work1 all of which must be carried out by hand1 with the exception of cutting the block to the outline of the propeller1 which may be done with a band saw1 a set of templates or gauges should be made from the drawings4 ,these will be necessary as guides for finishing the propeller accurately4 ,draw the sections out full size on sheets of cardboard or tin and cut out along the curves1 finally dividing each sheet into two parts1 one for the upper side and one for the lower4 ,care must be taken to get the sides of the template square1 and when they are used1 the propeller should be laid on a perfectly true and flat block4 ,each template should be marked as it is finished1 to indicate what part of the blade it is a gauge for4 ,the work of cutting the laminated block down to the lines represented by the templates is carried out with the aid of the plane1 spoke shave1 and gouge4 ,after the first roughing out to approximate the curvature of the finished propeller is completed1 the cuts taken should be very fine1 as it will be an easy matter to go too deep1 thus spoiling the block and necessitating a new start with fresh material4 ,for finishing1 pieces of broken glass are employed to scrape the wood to a smooth surface1 followed by coarse and finally by fine sandpaper4 ,mounting4 ,the hub should be of the same diameter as the flange on the engine crank shaft to which the flywheel was bolted1 and should have its bolt holes drilled to correspond4 ,to strengthen the hub1 light steel plates of the same diameter are screwed to it1 front and back1 and the bolt holes drilled right through the metal and wood4 ,this method of fastening is recommended where it is possible to substitute the propeller for the flywheel formerly on the engine1 it being common practice to omit the use of the flywheel altogether4 ,the writer does not recommend this1 however1 as the advantages of smoother running and more reliable operation gained by the use of a flywheel in addition to the propeller far more than offset any disadvantage represented by its weight4 ,it will be noted that the ,wright motors have always been equipped with a flywheel of ample size and weight and this is undoubtedly responsible1 in some measure at least1 for the fact that the ,wright biplanes fly with considerably less power than is ordinarily employed for machines of the same size4 ,if the motor selected be equipped with an unusually heavy flywheel1 and particularly where the wheel is of comparatively small diameter1 making it less effective as a balancer1 it may be replaced with one of lighter weight and larger diameter4 ,it may be possible to attach it by keying to the forward end of the crank shaft1 thus leaving the flange from which the flywheel was taken free for mounting the propeller4 ,an ordinary belt pulley will serve excellently as the new flywheel1 as most of its weight is centered in its rim1 but as the common cast-iron belt pulley of commerce is seldom intended to run at any such speed as that of an automobile motor1 it should be examined carefully for flaws4 ,otherwise1 there will be danger of its blunting with disastrous results under the influence of centrifugal force4 ,its diameter should not exceed #af inches in order to keep its peripheral speed within reasonable limits4 ,where the mounting of the motor permits of its use1 a wood pulley #ah to #bj inches in diameter with a steel band about #a_/h to #a_/d-;inch thick1 shrunk on its periphery1 may be employed4 ,most builders will ridicule the idea of a flywheel other than the propeller itself4 ,you do not need it2 so why carry the extra weight8 will be their query4 ,it is not absolutely necessary1 but it is an advantage4 ,in case the flywheel of the engine selected is keyed to the crank shaft1 or in case it is not possible to mount both the flywheel and the propeller on different ends of the crank shaft1 some other expedient rather than that of bolting to the flange must be adopted4 ,in such a case1 the original flywheel1 where practical to retain it1 may be drilled and tapped and the propeller attached directly to it4 ,where the flywheel can not be kept1 it will usually be found practical to cut off its rim and bolt the propeller either to the web or spokes1 or to the flywheel hub1 if it be cut down to the latter4 ,the drawing4 ,fig4 #ba1 shows the rear or concave side of the propeller4 ,from the viewpoint of a man standing in its wind and facing forward1 it turns to the left1 or anti-clockwise4 ,on many of the propellers now on the market1 the curved edge is designed to go first4 ,this type may have greater advantages over that described1 but the straight front edge propeller is easier for the amateur to make4 99,mounting the ,engine994 ,having completed the propeller1 the next step is the mounting of the engine4 ,reference to the types available to the amateur aeroplane builder has already been made4 ,there are a number of motors now on the market that have been designed specially for this purpose and not a few of them are of considerable merit4 ,their cost ranges from about #bej up to #b1ejj1 but it may be possible to pick up a comparatively light-weight automobile motor second hand which will serve all purposes and which will cost far less than the cheapest aeronautic motor on the market4 ,it must be capable of developing #cj actual horse-power at #a1jjj to #a1bjj r4p4m4 and must not exceed #djj pounds complete with all accessories1 such as the radiator and piping1 magneto1 water1 oil1 etc4 ,considerable weight may be saved on an automobile motor by removing the exhaust manifold and substituting a lighter flywheel for the one originally on the engine--or omitting it altogether1 as just mentioned4 ,a light-weight aeronautic radiator should be used in preference to the usual automobile radiator4 ,when placing the engine in position on the ash beams forming its bed or support1 it must be borne in mind that the complete machine1 with the operator in the aviator's seat1 is designed to balance on a point about #a #a_/b feet back of the front edge of the main planes4 ,as the operator and the motor represent much the larger part of the total weight1 the balance may easily be regulated by moving them slightly forward or backward1 as may be required4 ,it will be necessary1 of course1 to place the engine far enough back in any case to permit the propeller blades to clear the planes4 ,the actual installation of the engine itself will be an easy matter for anyone who has had any experience in either automobile or marine gasoline motor work4 ,it is designed to be bolted to the two engine beams in the same manner as on the side members of the frame of an automobile1 or the engine bed in a boat4 ,just in front of the engine is the best place for the gasoline tank1 which should be cylindrical with tapering ends1 to cut down its wind resistance4 ,if the designer is not anxious to carry out points as fine as this1 a light copper cylindrical tank may be purchased from stock4 ,it should hold at least ten gallons of gasoline4 ,in front of the tank is the radiator4 99,controls994 ,the controls may be located to conform to the builder's own ideas of accessibility and convenience4 ,usually the switch is placed on the steering column1 and it may be of the ordinary knife variety1 or one of the special switches made for this purpose1 as taste may dictate4 ,the throttle control and spark advance may either be in the form of pedals1 working against springs1 or of small levers working on a notched sector1 at the side of the seat4 ,the complete control1 levers1 and sector may be purchased ready to mount whenever desired1 as they are made in this form for both automobile and marine work4 ,this likewise applies to the wheel1 which it would not pay the amateur to attempt to make4 ,another pedal should work a brake on the front wheel1 the brake shoe consisting of a strip of sheet steel1 fastened at one end to the fore part of the skid and pressed against the wheel by a bamboo rod directly connected with the brake pedal4 ,an emergency brake can also be made by loosely bolting a stout bar of steel on the skid near its rear end2 one end of this bar is connected to a lever near the seat1 so that when this lever is pulled back the other end of the bar tends to dig into the ground4 ,as making a landing is one of the most difficult feats for the amateur aviator to master and sufficient space for a long run after alighting is not always available1 these brakes will be found a very important feature of the machine4 ,illustration3 ,fig4 #bb4 ,method of ,starting the ,engine of an ,aeroplane ,the engine is started by swinging the propeller1 and this is an operation requiring far more caution than cranking an automobile motor4 ,both hands should be placed on the same blade4 ,fig4 #bb1 and the latter should always be pulled downward--never upward4 ,with the switch off1 first turn the propeller over several times to fill the cylinders with gas1 leaving it just ahead of dead center of one of the cylinders1 and with one blade extending upward and to the left at a #de-;degree angle4 ,after closing the switch1 take the left blade with both hands and swing it downward sharply1 getting out of the way of the following blade as quickly as possible4 99,tests994 ,the first thing to be done after the propeller is finished and mounted on the engine is to test the combination1 or power plant of the biplane1 for speed and thrust1 or pulling power4 ,from these two quantities it will be easy to figure the power that the engine is delivering4 ,the only instruments necessary are a spring balance reading to #cjj pounds or over2 a revolution counter1 such as may be procured at any machinist's supply house for a dollar or two2 and a watch4 ,one end of the spring balance is fastened to the front end of the skid and the other to a heavy stake firmly driven in the ground a few feet back4 ,the wheels of the biplane should be set on smooth boards so that they will not offer any resistance to the forward thrust4 ,when the engine is started the spring balance will give a direct reading of the pull of the propeller4 ,with one observer noting the thrust1 another should check the number of revolutions the engine is turning per minute4 ,to do this1 a small hole should previously have been countersunk in the hub of the propeller to receive the conical rubber tip of the revolution counter4 ,the observer stands behind the propeller1 watch in one hand and revolution counter in the other4 ,at the beginning of the minute period1 the counter is pressed firmly against the hub1 and quickly withdrawn at the end of the minute4 ,a stop watch is naturally an advantage for the purpose4 ,the horse-power is figured as follows1 assuming1 for example1 a thrust of #bej pounds at #a1bjj r4p4m4 #bej ,x #abjj ,x #c4e ,x #ajj _/ #cc4jjj ,x #he #cg h4 p4 ,as before1 the #ajj_/he allows for the slip and represents the efficiency of the propeller2 #cc1jjj is the number of foot pounds per minute or the equivalent of one horse-power1 and #c4e is the pitch of the propeller4 99,assembling the ,biplane994 ,assembling the machine complete requires more space than is available in the average workshop4 ,however1 it is possible to assemble the sections of the planes in a comparatively small room1 carrying the work far enough to make sure that everything will go together properly when the time comes for complete assembly at the testing ground4 ,in this case1 it is preferable to assemble the end sections first1 standing them away when complete to make room for the central section1 on which the running gear and outriggers are to be built up4 ,the builder will have decided by this time whether he will make his machine on the regular plan1 with one main rib between each section1 or on the quick-detachable plan1 which has two main ribs on either side of the central section1 as previously explained4 ,it is desirable to be able to assemble two sections at once and this should be possible anywhere as it requires a space only about #f by #ac feet4 ,two wood #b,x#d's1 about #ab feet long1 should be nailed down on the blocks on the floor2 make these level and parallel to each other at a distance of #c feet #f inches on centers1 one being #c inches higher than the other4 ,strips of wood should be nailed on them1 so as to hold the main beams of the frame in place while assembling4 ,the two front and two rear beam sections are laid in place and joined with the sheet-steel sleeves1 the flanges of the sleeves on the inner side of the beams4 ,then through the sleeves in the front beams1 which are1 of course1 those on the higher bed1 drill the holes for the strut socket bolts 7#a_/d inch74 ,the holes for the outer ones go through the projecting ends of the beams2 those for the inner ones are half in each of the two abutting beams4 ,at the end where the central section joins on1 a short length of wood of the same section may be inserted in the sleeve while drilling the hole4 ,an assistant should hold the beams firmly together while the holes are being drilled4 ,now lay in place the three main ribs belonging to the two sections under construction and fasten them at the front ends by putting in place the strut sockets for which the holes have been drilled1 with a turnbuckle plate under each socket1 ,fig4 #af4 ,the strut socket bolt passes through the main rib and the beam4 ,the bed on which the assembling is being done1 should be cut when sufficiently under the joints to leave room for the projecting bolt ends4 ,set the ribs square with the front beams1 then arrange the rear beams so that their joints come exactly under the ribs2 clamp the ribs down and drill a true1 vertical hole through the rib beam1 holding the two sections of the beam together as before4 ,then put the rear strut sockets in place1 using the angle washers previously described1 above and below the rib4 ,when the quick-detachable plan is followed1 the ribs at the inner ends of the double section1 where they join the central section1 should be bolted on an inch from the ends of the beam1 using #a_/d-;inch stove bolts instead of the socket bolts4 ,the sleeves should be slotted1 so that they can slide off without removing these bolts1 as the sleeves and ribs which occupy the position over the joints of the beams1 belong to the central section4 ,the sections should now be strung up with the diagonal truss wires which will make them rigid enough to stand handling4 ,the wires are attached at each end to the flange bolts of the sleeves4 ,either one or two turnbuckles may be used on each wire1 as already explained2 if but one turnbuckle be used1 the other end of the wire may be conveniently attached to a strip of sheet steel bent double and drilled for the bolt1 like the sheet-steel slip of a turnbuckle4 ,the attachment1 of whatever nature1 should be put between the end and the flange of the sleeve1 not between the two flanges4 ,three or four ribs can be used on each section2 four are preferable on sections of full #f-;foot length4 ,they are1 of course1 evenly spaced on centers4 ,at the front ends1 they are attached to the beam by wood screws through their flattened ferrules4 ,the attachment to the rear beam is made with a slip of sheet steel measuring #a_/b by #c inches1 bent over the rib and fastened to the beam at each side with a wood screw4 ,a long wire nail is driven through the rib itself on the beam4 ,four double sections should be built up in this manner1 the right and left upper and the right and left lower sections4 ,uppers and lowers are alike except for the inversion of the sockets in the upper sections4 ,rights and lefts differ in that the outer beams are long enough to fill up the sleeves1 not leaving room for another beam to join on4 ,inserting the struts in their sockets between the upper and lower sections of the same side will now form either of the two sides of the machine complete4 ,care should be taken to get the rear struts the proper length with respect to the front ones to bring the upper and lower planes parallel4 ,the distance from the top of the lower front beam to the top of the upper front beam should be the same as the distance between the rows of bracing holes in the upper and lower main ribs just above and below the rear struts--about #d feet #f inches4 ,it should hardly be necessary to mention that the thick edges of the struts come to the front--they are fish-shaped and a fish is thicker at the head than at the tail4 ,the truss wires may now be strung on in each square of the struts1 beams1 and main ribs1 using turnbuckles as previously described4 ,the wires should be taut enough to sing a low note when plucked between the thumb and forefinger4 ,if the construction is carried out properly1 the framework will stand square and true with an even tension on all the wires4 ,it is permissible for the struts to slant backward a little as seen from the side1 but all should be perfectly in line4 ,for adjusting the turnbuckles1 the builder should make for himself a handy little tool usually termed a nipple wrench4 ,it is simply a strip of steel #a #a_/b by #a_/b by #c_/cb inches1 with a notch cut in the middle of the long sides to fit the flattened ends of the turnbuckle nipples4 ,this is much handier than the pliers and does not burr up the nipples4 ,it has been assumed in this description of the assembling that the builder is working in a limited space2 if1 on the contrary1 he has room enough to set up the whole frame at once1 the work will be much simpler4 ,in this case1 the construction bed should be #cj feet long4 ,first build up the upper plane complete1 standing it against the wall when finished2 then build the lower plane1 put the struts in their sockets1 and lay on the upper plane complete4 ,returning to the plan of assembly by sections1 after the side sections or wings of the machine have been completed1 the struts may be taken out and the sections laid aside4 ,the middle section1 to which the running gear and outriggers will be attached1 is now to be built up in the same way4 ,if the builder is following the plan in which there is one main rib between each section1 it will be necessary to take off the four inner main ribs from the sections already completed1 to be used at the ends of the central section4 ,the plan drawing of the complete machine shows that the ribs of the central section are cut off just back of the rear beam to make room for the propeller4 ,this is necessary in order to set the motor far enough forward to balance the machine properly4 ,the small ribs in this section have the same curve but are cut off #aj inches shorter at their rear ends1 and the stumps are smoothed down for ferrules like those for the other small ribs4 ,in the plan which has one main rib between each section1 the main rib on each side of the central section must be left full length4 ,in the quick-detachable plan with two main ribs on each side of the central section1 the inner ones1 which really belong to this section1 are cut off short like the small ribs4 ,in the drawing of the complete machine1 the distance between the struts which carry the engine bed is shown as #b feet4 ,this is only approximate1 as the distance must be varied to suit the motor employed4 ,by this time1 the builder will have decided what engine he is going to use--or can get--and should drill the holes for the sockets of these struts with due respect to the width of the engine's supporting feet or lugs1 remembering that the engine bed beams go on the inside of the struts4 ,in the drawing of the running gear4 ,fig4 #ag1 the distance between the engine-bed struts has been designated ,a4 ,the distances1 ,b1 on each side are1 of course1 approximately 7#f'-- #b99;,a9971 whatever ,a may be4 ,illustration3 ,,view ,,of ,,the ,,french ,,aviation ,,grounds ,,showing ,,the ,,hangars ,,ranged ,,along ,,the ,,edges ,,of ,,the ,,field ,this ,photograph ,protected ,by ,international ,copyright ,,examination ,,paper ,,building ,,and ,,flying ,,an ,,aeroplane 99,,part ,i99 99,read ,carefully993 ,place your name and full address at the head of the paper4 ,any cheap1 light paper like the sample previously sent you may be used4 ,do not crowd your work1 but arrange it neatly and legibly4 ,do not copy the answers from the ,instruction ,paper2 use your own words so that we may be sure that you understand the subject4 #a4 ,what type of machine1 biplane or monoplane1 makes the best glider and why8 #b4 ,give the dimensions of a glider which will support a man's weight4 #c4 ,in a glider which has no rudder1 how is the machine controlled8 #d4 ,give carefully the details of the start in making a glide4 #e4 ,in what direction relative to the wind should a glide be made8 ,justify your answer4 #f4 ,how must the stability and balance of a glider in flight be controlled8 #g4 ,state the proper conditions for a successful glide4 #h4 ,give the essential characteristics of a ,curtiss aeroplane1 defining the various parts4 #i4 ,describe briefly the details of construction of the main supporting surfaces of a ,curtiss4 #aj4 ,draw a diagram of the assembled planes showing how the struts and cross wires are placed to give the required rigidity4 #aa4 ,give the details of the running gear of the ,curtiss4 #ab4 ,what is the office of the ,curtiss ailerons and how are they controlled from the operator's seat8 ,draw sketch4 #ac4 ,describe the details of the front and rear outriggers4 #ad4 ,what type of propeller is advised for the ,curtiss8 ,give the details of its construction4 #ae4 ,describe carefully the manner in which a propeller should move through the air in order to give the maximum propulsion4 #af4 ,what determines the exact location of the motor in the aeroplane8 #ag4 ,give correct method of starting the motor when ready for a flight4 #ah4 ,what tests should be conducted before a flight is undertaken8 99,after completing the work1 add and sign the following statement399 ,i hereby certify that the above work is entirely my own4 7,signed7 ,,part ,,ii ,,building ,a ,,bleriot ,,monoplane ,as mentioned in connection with the description of its construction1 the ,curtiss biplane was selected as a standard of this type of aeroplane after which the student could safely pattern for a number of reasons4 ,it is not only remarkably simple in construction1 easily built by anyone with moderate facilities and at a slight outlay1 but it is likewise the easiest machine to learn to drive4 ,the monoplane is far more difficult and expensive to build4 ,the ,bleriot may be regarded as the most typical example in this field1 in view of its great success and the very large numbers which have been turned out4 ,in fact1 the ,bleriot monoplane is the product of a factory which would compare favorably with some of the large automobile plants4 ,its construction requires skillful workmanship both in wood and metal1 and a great many special castings1 forgings1 and stampings are necessary4 ,although some concerns in this country advertise that they carry these fittings as stock parts1 they are not always correct in design and1 in any case1 are expensive4 ,wherever it is possible to avoid the use of such parts by any expedient1 both forms of construction are described1 so that the builder may take his choice4 ,bleriot monoplanes are made in a number of different models1 the principal ones being the #cj-;horse-power runabout1 ,figs4 #bc and #bd1 the #ej- and #gj-;horse-power passenger-carrying machines1 and the #ej-1 #gj-1 and #ajj-;horse-power racing machines4 ,of these the first has been chosen as best adapted to the purpose4 ,its construction is typical of the higher-power monoplanes of the same make1 and it is more suitable for the beginner to fly as well as to build4 ,it is employed exclusively by the ,bleriot schools4 ,illustration3 ,fig4 #bc4 ,details of ,bleriot ,monoplane 99,motor994 ,the motor regularly employed is the #cj-;horse-power1 three-cylinder ,anzani1 a two-cylinder type of which is shown in ,aeronautical ,motors ,fig4 #dj4 ,from the amateur's standpoint1 a disadvantage of the ,bleriot is the very short space allowed for the installation of the motor4 ,for this reason1 the power plant must be fan shaped1 like the ,anzani2 star form1 like the ,gnome2 or of the two-cylinder opposed type4 ,it must likewise be air-cooled1 as there is no space available for a radiator4 ,illustration3 ,fig4 #bd4 ,side ,elevation of ,bleriot ,monoplane ,illustration3 ,fig4 #be4 ,top and ,side ,view of ,bleriot ,fuselage on ,which ,machine ,is ,assembled 99,fuselage994 ,like most monoplanes1 the ,bleriot has a long central body1 usually termed fuselage1 to which the wings1 running gear1 and controls are all attached4 ,a drawing of the fuselage with all dimensions is reproduced in ,fig4 #be1 and as the machine is1 to a large extent1 built up around this essential1 its construction is taken up first4 ,it consists of four long beams united by #ce crosspieces4 ,the beams are of ash1 #a #c_/af inches square for the first third of their length and tapering to #g_/h inch square at the rear ends4 ,owing to the difficulty of securing good pieces of wood the full length1 and also to facilitate packing for shipment1 the beams are made in halves1 the abutting ends being joined by sleeves of #a #a_/h-;inch1 #bj-;gauge steel tubing1 each held on by two #a_/h-;inch bolts4 ,although the length of the fuselage is #ba feet #aa #a_/d inches1 the beams must be made of two #aa-;foot halves to allow for the curve at the rear ends4 ,illustration3 ,fig4 #bf4 ,details of ,u-bolt ,which is a ,feature of ,bleriot ,construction ,the struts are also of ash1 the majority of them being #g_/h by #a #a_/d inches1 and oval in section except for an inch and a half at each end4 ,but the first1 second1 and third struts 7counting from the forward end7 on each side1 the first and second on the top1 and the first strut on the bottom are #a #c_/af inches square1 of the same stock as the main beams4 ,practically all of the struts are joined to the main beams by ,u-bolts1 as shown by the detail drawing1 ,fig4 #bf1 this being one of ,louis ,bleriot's inventions4 ,the small struts are held by #a_/h-;inch bolts and the larger ones by #c_/af-;inch bolts4 ,the ends of the struts must be slotted for these bolts1 this being done by drilling three holes in a row with a #e_/cb- or #g_/cb-;inch drill1 according to whether the slot is for the smaller or larger size bolt4 ,the wood between the holes is cut out with a sharp knife and the slot finished with a coarse1 flat file4 ,all of the ,u-bolts measure #b inches between the ends4 ,the vertical struts are set #a inch forward of the corresponding horizontal struts1 so that the four holes through the beam at each joint are spaced #a inch apart1 alternately horizontal and vertical4 ,to the projecting angles of the ,u-bolts are attached the diagonal truss wires1 which cross all the rectangles of the fuselage1 except that in which the driver sits4 ,this trussing should be of #bj-;gauge piano wire 7music-wire gauge7 or #a_/aj-;inch cable1 except in the rectangles bounded by the large struts1 where it should be #be-;gauge piano wire or #c_/cb-;inch cable4 ,each wire1 of course1 should have a turnbuckle4 ,about #ajj of these will be required1 either of the spoke type or the regular type1 with two screw eyes--the latter preferred4 ,transverse squares1 formed by the two horizontal and two vertical struts at each point1 are also trussed with diagonal wires4 ,although turnbuckles are sometimes omitted on these wires1 it takes considerable skill to get accurate adjustments without them4 ,the extreme rear strut to which the rudder is attached1 is not fastened in the usual way4 ,it should be cut with tongues at top and bottom1 fitting into notches in the ends of the beams1 and the whole bound with straps of #bj-;gauge sheet steel1 bolted through the beams with #a_/h-;inch bolts4 ,continuing forward1 the struts have no peculiarity until the upper horizontal one is reached1 just behind the driver's seat4 ,as it is impossible to truss the quadrangle forward of this strut1 owing to the position of the driver's body1 the strut is braced with a ,u-shaped half-round strip of #a_/b by #a inch of ash or hickory bolted to the beams at the sides and to the strut at the rear1 with two #a_/h-;inch bolts at each point4 ,the front side of the strut should be left square where this brace is in contact with it4 ,the brace should be steam bent with the curves on a #i-;inch radius1 and the half-round side on the inside of the curve4 ,the vertical struts just forward of the driver's seat carry the inner ends of the rear wing beams4 ,each beam is attached with a single bolt1 giving the necessary freedom to rock up and down in warping the wings4 ,the upper #f inches of each of these struts fits into a socket designed to reinforce it4 ,in the genuine ,bleriot1 this socket is an aluminum casting4 ,however1 a socket which many would regard as even better can be made from a #g-;inch length of #bj-;gauge #a #a_/h-;inch square tubing4 ,one end of the tube is sawed one inch through the corners2 two opposite sides are then bent down at right angles to form flanges1 and the other two sides sawed off4 ,a #a- by #c-;inch strip of #bj-;gauge sheet steel1 brazed across the top and flanges completes the socket4 ,with a little care1 a very creditable socket can be made in this way4 ,finally1 with the strut in place1 a #c_/h-;inch hole is drilled through #d inches from the top of the socket for the bolt securing the wing beam4 ,the upper horizontal strut at this point should be arched about six inches to give plenty of elbow room over the steering wheel4 ,the bending should be done in a steam press4 ,the strut should be #a #c_/af inches square1 cut sufficiently long to allow for the curve1 and fitted at the ends with sockets as described above1 but set at an angle by sawing the square tube down further on one side than on the other4 ,on the two lower beams1 is laid a floor of half-inch boards1 extending one foot forward and one foot back of the center line of the horizontal strut4 ,this floor may be of spruce1 if it is desired to save a little weight1 or of ordinary tongue-and-grooved floor boards1 fastened to the beams with wood screws or bolts4 ,the horizontal strut under this floor may be omitted1 but its presence adds but little weight and completes the trussing4 ,across the top of the fuselage above the first upper horizontal strut1 lies a steel tube which forms the sockets for the inner end of the front wing beams4 ,this tube is #a #c_/d inches diameter1 #ah gauge1 and #bf #c_/d inches long4 ,it is held fast by two steel straps1 #af gauge and #a inch wide1 clamped down by the nuts of the vertical strut ,u-bolts4 ,the center of the tube is1 therefore1 in line with the center of the vertical struts1 not the horizontal ones4 ,the ,u-bolts which make this attachment are1 of course1 the #c_/af-;inch size1 and one inch longer on each end than usual4 ,to make a neat job1 the tube may be seated in wood blocks1 suitably shaped1 but these must not raise it more than a small fraction of an inch above the top of the fuselage1 as this would increase the angle of incidence of the wings4 ,the first vertical struts on each side are extras1 without corresponding horizontal ones2 they serve only to support the engine4 ,when the ,gnome motor is used1 its central shaft is carried at the centers of two 99,x99-shaped1 pressed-steel frames1 one on the front side1 flush with the end of the fuselage and one on the rear4 99,truss ,frame ,built on ,fuselage994 ,in connection with the fuselage may be considered the overhead truss frame and the warping frame4 ,the former consists of two inverted 99,v99's of #bj-;gauge1 #a- by #c_/h-;inch oval tubing1 joined at their apexes by a #bj-;gauge1 #c_/d-;inch tube4 ,each 99,v99 is formed of a single piece of the oval tubing about #e feet long4 ,the flattened ends of the horizontal tube are fastened by a bolt in the angles of the 99,v99's4 ,the center of the horizontal tube should be #b feet above the top of the fuselage4 ,the flattened lower ends of the rear 99,v99 should be riveted and brazed to strips of #ah-;gauge steel1 which will fit over the bolts attaching the vertical fuselage struts at this point4 ,the legs of the front 99,v99 should be slightly shorter1 as they rest on top of the wing socket tube4 ,each should be held down by a single #c_/af-;inch bolt1 passing through the upper wall of the tube and its retaining strap2 these bolts also serve the purpose of preventing the tube from sliding out from under the strap4 ,each side of the frame is now braced by diagonal wires 7,no4 #bj piano wire1 or #a_/ad-;inch cable7 with turnbuckles4 ,at the upper corners of this frame are attached the wires which truss the upper sides of the wings4 ,the front wires are simply fastened under the head and nut of the bolt which holds the frame together at this corner4 ,the attachment of the rear wires1 however1 is more complex1 as these wires must run over pulleys to allow for the rocking of the rear wing beams when the wings are warped4 ,to provide a suitable place for the pulleys1 the angle of the rear 99,v99 is enclosed by two plates of #bj-;gauge sheet steel1 one on the front and one on the rear1 forming a triangular box #a inch thick fore and aft1 and about #b inches on each side1 only the bottom side being open4 ,these plates are clamped together by a #c_/af-;inch steel bolt1 on which are mounted the pulleys4 ,there should be sufficient clearance for pulleys #a inch in diameter4 ,the wires running over these pulleys must then pass through holes drilled in the tube4 ,the holes should not be drilled until the wings are on1 when the proper angle for them can be seen4 ,the cutting and bending of the steel plates is a matter of some difficulty1 and should not be done until the frame is otherwise assembled1 so that paper patterns can be cut for them4 ,they should have flanges bent around the tube1 secured by the bolts which hold the frame together1 to keep them from slipping off4 ,the oval tubing is used in the vertical parts of this frame1 principally to reduce the wind resistance1 being placed with the narrow side to the front4 ,however1 if this tubing be difficult to obtain1 or if price is a consideration1 no harm will be done by using #c_/d-;inch round tubing4 ,beneath the floor of the driver's cockpit in the fuselage is the warping frame1 the support for the wires which truss the rear wing beams and also control the warping4 ,this frame is built up of four #c_/d-;inch1 #bj-;gauge steel tubes1 each about #c feet long1 forming an inverted1 #d-sided pyramid4 ,the front and back pairs of tubes are fastened to the lower fuselage beams with #c_/af-;inch bolts at points #ae inches front and back of the horizontal strut4 ,at their lower ends the tubes are joined by a fixture which carries the pulleys for the warping wires and the lever by which the pulleys are turned4 ,in the genuine ,bleriot1 this fixture is a special casting4 ,however1 a very neat connection can be made with a piece of #a_/af-;inch steel stock1 #a #a_/d by #f inches1 bent into a 99,u99-shape with the legs #a inch apart inside4 ,the flattened ends of the tubes are riveted and brazed to the outside upper corners of the 99,u991 and a bolt to carry the pulleys passes through the lower part1 high enough to give clearance for #b-;inch pulleys4 ,this frame needs no diagonal wires4 99,running ,gear994 ,passing now to the running gear1 the builder will encounter the most difficult part of the entire machine1 and it is impossible to avoid the use of a few special castings4 ,the general plan of the running gear is shown in the drawing of the complete machine4 ,figs4 #bc and #bd1 while some of the details are illustrated in ,fig4 #bg1 and the remainder are given in the detail sheet1 ,fig4 #bh4 ,it will be seen that each of the two wheels is carried in a double fork1 the lower fork acting simply as a radius rod1 while the upper fork is attached to a slide which is free to move up and down on a #b-;inch steel tube4 ,this slide is held down by two tension springs1 consisting of either rubber tubes or steel coil springs1 which absorb the shocks of landing4 ,the whole construction is such that the wheels are free to pivot sideways around the tubes1 so that when landing in a quartering wind the wheels automatically adjust themselves to the direction of the machine4 ,illustration3 ,a ,,french ,,development ,,of ,,the ,,wright ,,machine ,,built ,,under ,,the ,,wright ,,patents ,there is ,little ,resemblance to the ,original ,except in ,wing ,form and ,warping ,framework4 ,the main framework of the running gear consists of two horizontal beams1 two vertical struts1 and two vertical tubes4 ,the beams are of ash1 #d #c_/d inches wide in the middle half1 tapering to #c #c_/d inches at the ends1 and #e feet #b #c_/d inches long overall4 ,the upper beam is ,h inch thick and the lower #a inch4 ,the edges of the beams are rounded off except at the points where they are drilled for bolt holes for the attachment of other parts4 ,the two upper beams of the fuselage rest on these beams and are secured to them by two #c_/af-;inch bolts each4 ,the vertical struts are also of ash1 #a #c_/af inch by #c inches and #d feet #b inches long overall4 ,they have tenons at each end which fit into corresponding square holes in the horizontal beams4 ,the two lower fuselage beams are fastened to these struts by two #c_/af-;inch through bolts and steel angle plates formed from #a_/af-;inch sheet steel4 ,the channel section member across the front sides of these struts is for the attachment of the motor1 and will be taken up later4 ,the general arrangement at this point depends largely on what motor is to be used1 and the struts should not be rounded or drilled for bolt holes until this has been decided4 ,from the lower ends of these struts ,,cc1 ,fig4 #bg1 diagonal struts ,,dd run back to the fuselage4 ,these are of ash1 #a #c_/af by #b #a_/b inches and #b feet inches long4 ,the rear ends of the struts ,,dd are fastened to the fuselage beams by the projecting ends of the 99,u99-bolts of the horizontal fuselage struts1 and also by angle plates of sheet steel4 ,at the lower front ends the struts ,,dd are fastened to the struts ,,cc and the beam ,e by steel angle plates1 and the beam is reinforced by other plates on its under side4 ,trussing4 ,in the genuine ,bleriot1 the framework is trussed by a single length of steel tape1 #a #a_/h by #a_/af inch and about #aa feet long1 fastened to ,u-bolts in the beam ,a1 ,fig4 #bg4 ,this tape runs down one side1 under the beam ,e1 and up the other side1 passing through the beam in two places1 where suitable slots must be cut4 ,the tape is not made in this country1 but must be imported at considerable expense4 ,ordinary sheet steel will not do4 ,if the tape can not be obtained1 a good substitute is #a_/h-;inch cable1 which then would be made in two pieces and fastened to eye bolts at each end4 ,illustration3 ,fig4 #bg4 ,details of ,bleriot ,running ,gear ,illustration3 ,fig4 #bh4 ,details of ,various ,fittings for ,bleriot ,monoplane ,the two steel tubes are #b inches in diameter1 #ah-;gauge1 and about #d feet #aj inches long4 ,at their lower ends they are flattened1 but cut away so that a #b-;inch ring will pass over them4 ,to these flattened ends are attached springs and wires which run from each tube across to the hub of the opposite wheel4 ,the purpose of these is simply to keep the wheels normally in position behind the tubes4 ,the tubes1 it will be noticed1 pass through the lower beam1 but are sunk only #a_/h inch into the upper beam4 ,they are held in place by sheet-steel sockets on the lower side of the upper beam and the upper side of the lower beam4 ,the other sides of the beams are provided with flat plates of sheet steel4 ,the genuine ,bleriot has these sockets stamped out of sheet steel1 but as the amateur builder will not have the facilities for doing this1 an alternative construction is given here4 ,in this method1 the plates are cut out to pattern1 the material being sheet steel #a_/af inch thick1 and a #a_/b-;inch hole drilled through the center1 a #b-;inch circle then being drawn around this4 ,then1 with a cold chisel a half dozen radial cuts are made between the hole and the circle4 ,finally this part of the plate is heated with a blow-torch and a #b-;inch piece of pipe driven through1 bending up the triangular corners4 ,these bent up corners are then brazed to the tubes1 and a strip of light sheet steel is brazed on to cover up the sharp edges4 ,of course1 the brazing should not be done until the slides ,,gg1 ,figs4 #bg and #bh1 have been put on4 ,when these are once in place1 they have to stay on and a breakage of one of them1 means the replacement of the tube as well4 ,this is a fault of the ,bleriot design that can not well be avoided4 ,it should be noticed that the socket at the upper end1 as well as its corresponding plate on the other side of the beam1 has extensions which reinforce the beam where the eye bolts or 99,u99-bolts for the attachment of the steel tape pass through4 ,forks4 ,next in order are the forks which carry the wheels4 ,the short forks ,,jj1 ,figs4 #bg and #bh1 which act simply as radius rods1 are made of #a- by #c_/h-;inch oval tubing1 a stock size which was specified for the overhead truss frame4 ,it will be noticed that these are in two parts1 fastened together with a bolt at the front end4 ,the regular ,bleriot construction calls for forged steel eyes to go in the ends of tubes1 but these will be hard to obtain4 ,the construction shown in the drawings is much simpler4 ,the ends of the tubes are heated and flattened until the walls are about #a_/af inch apart inside4 ,then a strip of #a_/af-;inch sheet steel is cut the right width to fit in the flattened end of the tube1 and brazed in place4 ,the bolt holes then pass through the combined thickness of the tube and the steel strip1 giving a better bearing surface1 which may be further increased by brazing on a washer4 ,the long forks ,,ff1 which transmit the landing shocks to the springs1 are naturally made of heavier material4 ,the proper size tubing for them is #a #a_/h by #e_/h inches1 this being the nearest equivalent to the #ad by #bh mm ,french tubing4 ,however1 this is not a stock size in this country and can only be procured by order1 or it can be made by rolling out #ae_/af-;inch round tubing4 ,if the oval tubing can not be secured1 the round can be employed instead1 other parts being modified to correspond4 ,the ends are reinforced in the same way as described for the small forks4 ,these forks are strengthened by aluminum clamps ,h1 ,figs4 #bg and #bh1 which keep the tubes from spreading apart4 ,here1 of course1 is another call for special castings1 but a handy workman may be able to improvise a satisfactory substitute from sheet steel4 ,on each tube there are four fittings3 ,at the bottom1 the collar ,m to which the fork ,j is attached1 and above1 the slide ,g and the clamps ,k and ,l1 which limit its movement4 ,the collar and slide should be forged1 but as this may be impossible1 the drawings have been proportioned for castings4 ,the work is simple and may be done by the amateur with little experience4 ,the projecting studs are pieces of #c_/d-;inch1 #ad-;gauge steel tubing screwed in tight and pinned1 though if these parts be forged1 the studs should be integral4 ,the clamps which limit the movement of the slides are to be whittled out of ash or some other hard wood4 ,the upper clamp is held in place by four bolts1 which are screwed up tight2 but when the machine makes a hard landing the clamp will yield a little and slip up the tube1 thus deadening the shock4 ,after such a landing1 the clamps should be inspected and again moved down a bit1 if necessary4 ,the lower clamps1 which1 of course1 only keep the wheels from hanging down too far1 have bolts passing clear through the tubes4 ,to the projecting lugs on the slides ,,gg are attached the rubber tube springs1 the lower ends connecting with eye bolts through the beam ,e4 ,these rubber tubes1 of which four will be needed1 are being made by several companies in this country and are sold by supply houses4 ,they should be about #ad inches long1 unstretched1 and #a #a_/d inches in diameter1 with steel tips at the ends for attachment4 ,hub ,attachments4 ,the hubs of the two wheels are connected with the link ,p1 with universal joints ,n ,n at each end4 ,in case the machine lands while drifting sidewise1 the wheel which touches the ground first will swing around to head in the direction in which the machine is actually moving1 and the link will cause the other wheel to assume a parallel position2 thus the machine can run diagonally on the ground without any tendency to upset4 ,this link is made of the same #a- by #c_/h-;inch oval tubing used elsewhere in the machine4 ,in the original ,bleriot1 the joints are carefully made up with steel forgings4 ,but joints which will serve the purpose can be improvised from a #a-;inch cube of hard wood and three steel straps1 as shown in the sketch1 ,fig4 #bg4 ,from each of these joints a wire runs diagonally to the bottom of the tube on the other side1 with a spring which holds the wheel in its normal position4 ,this spring should be either a rubber tube1 like those described above1 but smaller1 or a steel coil spring4 ,in the latter case1 it should be of twenty #c_/d-;inch coils of ,no4 #be piano wire4 ,wheels4 ,the wheels are regularly #bh by #b inches1 corresponding to the #gjj by #ej mm ,french size1 with #cj spokes of #ab-;gauge wire4 ,the hub should be #e #a_/d inches wide1 with a #e_/h-;inch bolt4 ,of course1 these sizes need not be followed exactly1 but any variations will involve corresponding changes in the dimensions of the forks4 ,the long fork goes on the hub inside of the short fork1 so that the inside measurement of the end of the big fork should correspond to the width of the hub1 and the inside measurement of the small fork should equal the outside measurement of the large fork4 ,rear ,skid4 ,several methods are employed for supporting the rear end of the fuselage when the machine is on the ground4 ,the first ,bleriot carried a small wheel in a fork provided with rubber springs1 the same as the front wheels4 ,the later models1 however1 have a double 99,u99-shaped skid1 as shown in ,figs4 #bc and #bd4 ,this skid is made of two #h-;foot strips of ash or hickory #a_/b by #c_/d inches1 steamed and bent to the 99,u99-shape as shown in the drawing of the complete machine4 ,illustration3 ,fig4 #bi4 ,details of ,framework of ,bleriot ,main ,supporting ,planes 99,wings994 ,having completed the fuselage and running gear1 the wings are next in order4 ,these are constructed in a manner which may seem unnecessarily complicated1 but which gives great strength for comparatively little weight4 ,each wing contains two stout ash beams which carry their share of the weight of the machine1 and #ab ribs which give the proper curvature to the surfaces and at the same time reinforce the beams4 ,these ribs in turn are tied together and reinforced by light strips running parallel to the main beams4 ,illustration3 ,fig4 #cj4 ,complete ,rib of ,bleriot ,wing and ,pattern from ,which ,web ,is ,cut ,in the drawing of the complete wing4 ,fig4 #bi1 the beams are designated by the letters ,b and ,e4 ,a is a sheet aluminum member intended to hold the cloth covering in shape on the front edge4 ,c1 ,d1 and ,f are pairs of strips 7one strip on top1 the other underneath7 which tie the ribs together4 ,g is a strip along the rear edge1 and ,h is a bent strip which gives the rounded shape to the end of the wing4 ,the ribs are designated by the numbers #a to #ab inclusive4 ,ribs4 ,the first and most difficult operation is to make the ribs4 ,these are built up of a spruce board #c_/af inch thick1 cut to shape on a jig saw1 with #c_/af- by #e_/h-;inch spruce strip stacked and glued to the upper and lower edges4 ,each rib thus has an ,i-beam section1 such as is used in structural steel work and automobile front axles4 ,each of the boards1 or webs as they are usually called1 is divided into three parts by the main beams which pass through it4 ,builders sometimes make the mistake of cutting out each web in three pieces1 but this makes it very difficult to put the rib together accurately4 ,each web should be cut out of a single piece1 as shown in the detail drawing4 ,fig4 #cj1 and the holes for the beams should be cut in after the top and bottom strips have been glued on4 ,the detail drawing1 ,fig4 #cj1 gives the dimensions of a typical rib4 ,this should be drawn out full size on a strip of tough paper1 and then a margin of #c_/af inch should be taken off all round except at the front end where the sheet aluminum member ,a goes on4 ,this allows for the thickness of the top and bottom strips4 ,in preparing the pattern for the jig saw1 the notches for strips ,c1 ,d1 and ,f should be disregarded2 neither should it be expected that the jig-saw operator will cut out the oval holes along the center of the web1 which are simply to lighten it4 ,the notches for the front ends of the top and bottom strips should also be smoothed over in the pattern4 ,when the pattern is ready1 a saw or planing mill provided with a saw suitable for the work1 should cut out the #dj ribs 7allowing a sufficient number for defective pieces and breakage7 for about #b4 ,the builder then cuts the notches and makes the oval openings with an auger and keyhole saw4 ,of course1 these holes need not be absolutely accurate1 but at least #c_/d inch of wood should be left all around them4 ,nine of the twelve ribs in each wing are exactly alike4 ,no4 #a1 which forms the inner end of the wing1 does not have any holes cut in the web1 and instead of the slot for the main beam ,b1 has a #a #c_/d-;inch round hole1 as the stub end of the beam is rounded to fit the socket tube4 7,see ,fig4 #bc47 ,rib ,no4 #aa is #e feet #aj #a_/b inches long1 and ,no4 #ab is #c feet long4 ,these can be whittled out by hand1 and the shape for them will be obvious as soon as the main part of the wing is put together4 ,the next step is to glue on the top and bottom strips4 ,the front ends should be put on first and held1 during the drying1 in a screw clamp1 the ends setting close up into the notches provided for them4 ,thin #a_/b-;inch brads should be driven in along the top and bottom at #a- to #b-;inch intervals4 ,the rear ends of the strips should be cut off to the proper length and whittled off a little on the inside1 so that there will be room between them for the strip ,g1 #a_/d inch thick4 ,finally1 cut the slots for the main beams1 using a bit and brace and the keyhole saw1 and the ribs will be ready to assemble4 ,beams and ,strips4 ,the main beams are of ash1 the front beam in each wing being #c #a_/d by #c_/d inches and the rear beam #b #a_/b by #e_/h inches4 ,they are not exactly rectangular but must be planed down slightly on the top and bottom edges1 so that they will fit into the irregularly-shaped slots left for them in the ribs4 ,the front beams1 as mentioned above1 have round stubs which fit into the socket tube on the fuselage4 ,these stubs may be made by bolting short pieces of ash board on each side of the end of the beam and rounding down the whole4 ,to give the wings their slight inclination1 or dihedral angle1 which will be apparent in the front view of the machine1 the stubs must lie at an angle of #b #a_/b degrees with the beam itself4 ,this angle should be laid out very carefully1 as a slight inaccuracy at this point will result in a much larger error at the tips4 ,the rear beams project about #b inches from the inner ribs4 ,the ends should be reinforced with bands of sheet steel to prevent splitting1 and each drilled with a #c_/h-;inch hole for the bolt which attaches to the fuselage strut4 ,a strip of heavy sheet steel should be bent to make an angle washer to fill up the triangular space between the beam and the strut2 the bolt hole should be drilled perpendicularly to the beam1 and not to the strut4 ,the outer ends of the beams1 beyond rib ,no4 #aj1 taper down to #a inch deep at the ends4 ,the aluminum member ,a1 ,fig4 #bi1 which holds the front edge of the wing in shape1 is made of a #d-;inch strip of fairly heavy sheet aluminum1 rolled into shape round a piece of half-round wood1 #b #a_/d inches in diameter4 ,as sheet aluminum usually comes in #f-;foot lengths1 each of these members will have to be made in two sections1 joined either by soldering 7if the builder has mastered this difficult process7 or by a number of small copper rivets4 ,no especial difficulties are presented by the strips1 ,c1 ,d1 and ,f1 which are of spruce #c_/af by #e_/h inch1 or by the rear edge strip ,g1 of spruce #a_/d by #a #a_/b inches4 ,each piece ,h should be #a by #a_/b inch half-round spruce1 bent into shape1 fitted into the aluminum piece at the front1 and at the rear flattened down to #a_/d inch and reinforced by a small strip glued to the back1 finally running into the strip ,g4 ,the exact curve of this piece does not matter1 provided it is the same on both wings4 ,assembling the ,wings4 ,assembling the wings is an operation which demands considerable care4 ,the main beams should first be laid across two horses1 set level so that there will be no strain on the framework as it is put together4 ,then the #ab ribs should be slipped over the beams and evenly spaced #ac inches apart to centers1 care being taken to see that each rib stands square with the beams1 ,fig4 #ca4 ,the ribs are not glued to the beams1 as this would make repairs difficult1 but are fastened with small nails4 ,strips ,c1 ,d1 and ,f1 ,fig1 #bi1 are next put in place1 simply being strung through the rows of holes provided for them in the ribs1 and fastened with brads4 ,then spacers of #c_/af-;inch spruce1 #b or #c inches long1 are placed between each pair of strips halfway between each rib1 and fastened with glue and brads4 ,this can be seen in the broken-off view of the wing in the front view drawing1 ,fig4 #bc4 ,the rear edge strip fits between the ends of the top and bottom strips of the ribs1 as mentioned above1 fastened with brads or with strips of sheet-aluminum tacked on4 ,illustration3 ,fig4 #ca4 ,assembling the ,main ,planes of a ,bleriot ,monoplane ,each wing is trussed by eight wires1 half above and half below2 half attached to the front and half to the rear beam4 ,in the genuine ,bleriot steel tape is used for the lower trussing of the main beams1 similar to the tape employed in the running gear1 but ,american builders prefer to use #a_/h-;inch cable4 ,the lower rear trussing should be #c_/cb- or #g_/fd-;inch cable1 and the upper trussing #c_/cb-;inch4 ,the beams are provided with sheet-steel fixtures for the attachment of the cables1 as shown in the broken-off wing view1 ,fig4 #bc4 ,these are cut from fairly-heavy metal1 and go in pairs1 one on each side of the end beam1 fasten with three #c_/af-;inch bolts4 ,they have lugs top and bottom4 ,they are placed between the fifth and sixth and ninth and tenth ribs on each side4 ,to resist the backward pressure of the air1 the wings are trussed with struts of #a-;inch spruce and #a_/af-;inch cable1 as shown in ,fig4 #bc4 ,the struts are placed between the cable attachments1 being provided with ferrules of flattened steel tubing arranged to allow the rear beam freedom to swing up and down4 ,the diagonal cables are provided with turnbuckles and run through the open spaces in the ribs4 99,control ,system994 ,the steering gear and tail construction of the ,bleriot are as distinctive as the swiveling wheels and the 99,u99-bolts1 and the word cloche applied to the bell-like attachment for the control wires1 has been adopted into the international vocabulary of aeroplaning4 ,the driver has between his knees a small steering wheel mounted on a short vertical post4 ,this wheel does not turn1 but instead the post has a universal joint at the bottom which allows it to be swung backward and forward or to either side4 ,the post is really a lever1 and the wheel a handle4 ,encircling the lower part of the post is a hemispherical bell--the cloche--with its bottom edge on the same level as the universal joint4 ,four wires are attached to the edge of the cloche4 ,those at the front and back are connected with the elevator1 and those at the sides with the wing-warping lever4 ,the connections are so arranged that pulling the wheel back starts the machine upward1 while pushing it forward causes it to descend1 and pulling to either side lowers that side and raises the other4 ,the machine can be kept on a level keel by the use of the wheel and cloche alone2 the aviator uses them just as if they were rigidly attached to the machine1 and by them he could move the machine bodily into the desired position4 ,in practice1 however1 it has been found that lateral stability can be maintained more easily by the use of the vertical rudder than by warping4 ,this is because the machine naturally tips inward on a turn1 and1 consequently1 a tip can be corrected by a partial turn in the other direction4 ,if1 for example1 the machine tips to the right1 the aviator steers slightly to the left1 and the machine comes back to a level keel without any noticeable change in direction4 ,under ordinary circumstances this plan is used altogether1 and the warping is used only on turns and in bad weather4 ,it will be noticed that the ,bleriot control system is almost identical with that of the ,henri ,farman biplane1 the only difference being that in the ,farman the cloche and wheel are replaced by a long lever4 ,the movements1 however1 remain the same1 and as there are probably more ,bleriot and ,farman machines in use than all other makes together1 this control may be regarded almost as a standard4 ,it is not as universal as the steering wheel1 gear shift1 and brake levers of the automobile1 but still it is a step in the right direction4 ,illustration3 ,fig4 #cb4 ,control ,device of ,steel ,tubing instead of ,bleriot ,cloche ,in the genuine ,bleriot1 the cloche is built up of two bells1 one inside the other1 both of sheet aluminum about #a_/af inch thick4 ,the outer bell is #aa inches in diameter and #c #a_/b inches deep1 and the inner one #aj inches in diameter and #b inches deep4 ,a ring of hard wood is clamped between their edges and the steering column1 an aluminum casting passing through their centers4 ,this construction is so complicated and requires so many special castings and parts that it is almost impossible for the amateur4 ,steering ,gear4 ,while not so neat1 the optional construction shown in the accompanying drawing1 ,fig4 #cb1 is equally effective4 ,in this plan1 the cloche is replaced by four 99,v99-shaped pieces of #a_/b-;inch1 #bj-;gauge steel tubing1 attached to a steering post of #a-;inch1 #bj-;gauge tubing4 ,at the lower end1 the post has a fork1 made of pieces of smaller tubing bent and brazed into place1 and this fork forms part of the universal joint on which the post is mounted4 ,the cross of the universal joint1 which is somewhat similar to those employed on automobiles1 can best be made of two pieces of heavy tubing1 #a_/b inch by #ab gauge1 each cut half away at the middle4 ,the two pieces are then fastened together by a small bolt and brazed for greater security4 ,the ends which are to go into the fork of the steering post must then be tapped for #c_/h-;inch machine screws4 ,the two other ends of the cross are carried on 99,v99's of #a_/b-;inch1 #bj-;gauge tubing1 spread far enough apart at the bottom to make a firm base1 and bolted to the floor of the cockpit4 ,the steering wheel itself is comparatively unimportant4 ,on the genuine ,bleriot it is a solid piece of wood #h inches in diameter1 with two holes cut in it for hand grips4 ,on the post just under the wheel are usually placed the spark and throttle levers4 ,it is rather difficult1 however1 to arrange the connections for these levers in such a way that they will not be affected by the movements of the post1 and for this reason many amateur builders place the levers at one side on one of the fuselage beams4 ,from the sides of the cloche1 or from the tubing triangles which may be substituted for it1 two heavy wires run straight down to the ends of the warping lever4 ,this lever1 together with two pulleys1 is mounted at the lower point of the warping frame already described4 ,the lever is #ab inches long1 #aa inches between the holes at its ends1 and #b inches wide in the middle2 it should be cut from a piece of sheet steel about #a_/af inch thick4 ,the pulleys should be #b #a_/b inches in diameter1 one of them bolted to the lever1 the other one running free4 ,the wires from the outer ends of the rear wing beams are joined by a piece of flexible control cable1 which is given a single turn over the free pulley4 ,the inner wires1 however1 each have a piece of flexible cable attached to their ends1 and these pieces of cable1 after being given a turn round the other pulley1 are made fast to the opposite ends of the warping lever4 ,these cables should be run over the pulleys1 not under1 so that when the cloche is pulled to the right1 the left wing will be warped downward4 ,it is a common mistake to assume that both pulleys are fastened to the warping lever2 but when this is done the outer wire slackens off and does not move in accord with the inner wire1 on account of the different angles at which they work4 ,foot ,levers4 ,the foot lever for steering is cut from a piece of wood #bb inches long1 hollowed out at the ends to form convenient rests for the feet4 ,the wires connecting the lever to the rudder may either be attached to this lever direct1 or1 if a neater construction is desired1 they may be attached to another lever under the floor of the cockpit4 ,in the latter case1 a short piece of #a-;inch steel tubing serves as a vertical shaft to connect the two levers1 which are fastened to the shaft by means of aluminum sockets such as may be obtained from any supply house4 ,the lower lever is #ab inches long and #b inches wide1 cut from #a_/af-;inch steel similar to the warping lever4 ,amateur builders often cross the rudder wires so that pressing the lever to the right will cause the machine to steer to the left4 ,this may seem more natural at first glance1 but it is not the ,bleriot way4 ,in the latter1 the wires are not crossed1 the idea being to facilitate the use of the vertical rudder for maintaining lateral equilibrium4 ,with this arrangement1 pressing the lever with the foot on the high side of the machine tends to bring it back to an even keel4 ,tail and ,elevator4 ,the tail and elevator planes are built up with ribs and tie strips in much the same manner as the wings4 ,however1 it will hardly pay to have these ribs cut out on a jig saw unless the builder can have this work done very cheaply4 ,it serves the purpose just as well to clamp together a number of strips of #c_/af-;inch spruce and plane them down by hand4 ,the ribs when finished should be #bd #a_/d inches long4 ,the greatest depth of the curve is #a #a_/d inches1 at a point one-third of the way back from the front edge1 and the greatest depth of the ribs themselves #b #a_/d inches1 at the same point4 ,sixteen ribs are required4 ,a steel tube #a inch by #bj gauge1 ,c1 ,fig4 #cc1 runs through both tail and elevators1 and is the means of moving the latter4 ,each rib at the point where the tube passes through1 is provided with an aluminum socket4 ,those on the tail ribs act merely as bearings for the tube1 but those on the elevator ribs are bolted fast1 so that the elevators must turn with the tube4 ,at its center the tube carries a lever ,g1 of #a_/af-;inch steel #ab by #b inches1 fastened on by two aluminum sockets1 one on each side4 ,from the top of the lever a wire runs to the front side of the cloche1 and from the bottom a second wire runs to the rear side of the cloche4 ,illustration3 ,fig4 #cc4 ,construction ,details of ,bleriot ,tail1 ,elevators1 and ,rudder ,illustration3 ,,an ,,old ,,dutch ,,windmill ,,and ,a ,,modern ,,french ,,aeroplane ,this ,photograph ,protected ,by ,international ,copyright ,illustration3 ,,view ,,of ,,the ,r4 ,e4 ,p4 ,,motor ,,and ,,landing ,,gear ,this ,machine is the ,work of ,one of the ,cleverest ,aeroplane ,designers in ,europe ,the tube is carried in two bearings ,,hh1 attached to the lower beams of the fuselage4 ,these are simply blocks of hard wood1 fastened by steel strips and bolts4 ,the angle of incidence of the tail is adjustable1 the tail itself being held in place by two vertical strips of steel rising from the rear edge and bolted to the fuselage1 as shown in the drawing1 ,fig4 #cc4 ,to prevent the tail from folding up under the air pressure to which it is subjected1 it is reinforced by two #c_/d-;inch1 #bj-;gauge steel tubes running down from the upper sides of the fuselage1 as shown in the drawing of the complete machine1 ,fig4 #bc4 ,the tail and elevators have two pairs of tie strips1 ,b and ,d1 ,fig4 #cc1 made of #c_/af- by #e_/h-;inch spruce4 ,the front edge ,a is half round1 #a- by #a_/b-;inch spruce1 and the rear edge ,e is a spruce strip #a_/d- by #a #a_/b-;inches4 ,the end pieces are curved4 ,rudder4 ,the rudder is built up on a piece of #a-;inch round spruce ,m1 corresponding in a way to the steel tube used for the elevators4 ,on this are mounted two long ribs ,,kk1 and a short rib ,j1 made of spruce #c_/h inch thick and #a #c_/h inches wide at the point where ,m passes through them4 ,they are fastened to ,m with #a_/h-;inch through bolts4 ,the rudder lever ,n1 of #a_/af-;inch steel1 #ab by #b inches1 is laid flat on ,j and bolted in place2 it is then trussed by wires running from each end to the rear ends of ,,kk4 ,from the lever other wires also run forward to the foot lever which controls the rudder4 ,the wires to the elevator and rudder should be of the flexible cable specially made for this purpose1 and should be supported by fairleaders attached to the fuselage struts4 ,fairleaders of different designs may be procured from supply houses1 or may be improvised4 ,ordinary screw eyes are often used1 or pieces of copper tubing1 bound to the struts with friction tape4 99,covering the ,planes994 ,covering the main planes1 tail1 elevators1 and rudder may well be left until the machine is otherwise ready for its trial trip1 as the cloth will not then be soiled by the dust and grime of the shop4 ,the cloth may be any of the standard brands which are on the market1 preferably in a rather light weight made specially for double-surfaced machines of this type2 or light-weight sail cloth may be used1 costing only #be or #cj cents a yard4 ,about #hj yards will be required1 assuming a width of #cf inches4 ,illustration3 ,fig4 #cd4 ,method of ,mounting ,fabric on ,main ,supporting ,frame ,except on the rudder1 the cloth is applied on the bias1 the idea being that with this arrangement the threads act like diagonal truss wires1 thus strengthening and bracing the framework4 ,when the cloth is to be put on in this way it must first be sewed together in sheets large enough to cover the entire plane4 ,each wing will require a sheet about #ad feet square1 and two sheets each #f feet square will be required for the elevators and tail4 ,the strips of cloth run diagonally across the sheets1 the longest strips in the wing sheets being #bj feet long4 ,application of the cloth to the wings1 ,fig4 #cd1 is best begun by fastening one edge of a sheet to the rear edge of the wing1 stretching the cloth as tight as can be done conveniently with one hand4 ,the cloth is then spread forward over the upper surface of the wing and is made fast along the inner end rib4 ,small copper tacks are used1 spaced #b inches apart on the upper side and #a inch on the lower side4 ,after the cloth has been tacked to the upper sides of all the ribs1 the wing is turned over and the cloth stretched over the lower side4 ,finally the raw edges are trimmed off and covered with light tape glued down1 tape also being glued over all the rows of tacks along the ribs1 making a neat finish and at the same time preventing the cloth from tearing off over the tack heads4 99,installation of ,motor994 ,as stated previously1 the ideal motor for a ,bleriot-type machine is short along the crank shaft1 as the available space in the fuselage is limited1 and air-cooled for the same reason4 ,genuine ,bleriots are always fitted with one of the special types of radial or rotary aeronautic motors1 which are always air-cooled4 ,next in popularity to these is the two-cylinder1 horizontal-opposed motor1 either air- or water-cooled4 ,however1 successful machines have been built with standard automobile-type1 four-cylinder1 water-cooled motors1 and with four-cylinder1 two-cycle1 aeronautic motors4 ,when the motor is water-cooled1 there will inevitably be some difficulty in finding room for a radiator of sufficient size4 ,one scheme is to use twin radiators1 one on each side of the fuselage1 inside of the main frame of the running gear4 ,another plan is to place the radiator underneath the fuselage1 using a supplementary water tank above the cylinders to facilitate circulation4 ,these two seem to be about the only practicable arrangements1 as behind the motor the radiator would not get enough air1 and above it would obstruct the view of the operator4 ,it is impossible to generalize to much effect about the method of supporting the motor in the fuselage1 as this must differ with the motor4 ,automobile-type motors will be carried on two heavy ash beams1 braced by lengths of steel tubing of about #a inch diameter and #af gauge4 ,when the seven-cylinder rotary ,gnome motor is used1 the crank shaft alone is supported2 it is carried at the center of two ,x-shaped frames of pressed steel1 one in front of and the other behind the motor4 ,the three-cylinder ,anzani motors are carried on four lengths of channel steel bent to fit around the upper and lower portions of the crank case1 which is of the motorcycle type4 ,considerable care should be taken to prevent the exhaust from blowing back into the operator's face as this sometimes carries with it drops of burning oil1 besides disagreeable smoke and fumes4 ,the usual plan is to arrange a sloping dashboard of sheet aluminum so as to deflect the gases down under the fuselage4 ,the three sections of the fuselage back of the engine section are usually covered on the sides and bottom with cloth like that used on the wings4 ,sometimes sheet aluminum is used to cover the section between the wing beams4 ,however1 those who are just learning to operate machines and are a little doubtful about their landings often leave off the covering in order to be able to see the ground immediately beneath their front wheels4 ,illustration3 ,fig4 #ce4 ,running ,gear of ,morane ,type of ,bleriot ,monoplane 99,new ,features994 ,morane ,landing ,gear4 ,although the regular ,bleriot landing gear already described1 has many advantages and ha4s been in use with only detail changes for several years1 some aviators prefer the landing gear of the new ,morane monoplane1 which in other respects closely resembles the ,bleriot4 ,this gear1 ,fig4 #ce1 is an adaptation of that long in use on the ,henri ,farman and ,sommer biplanes1 combining skids and wheels with rubber-band springs4 ,in case a wheel or spring breaks1 whether due to a defect or to a rough landing1 the skids often save an upset4 ,besides1 the tension of the springs is usually such that on a rough landing the wheels jump up and allow the skids to take the shock2 this also prevents the excessive rebound of the ,bleriot springs under similar conditions4 ,another advantage which may have some weight with the amateur builder1 is that the ,morane running gear is much cheaper and easier to construct4 ,instead of the two heavy tubes1 the four forks of oval tubing1 and the many slides1 collars1 and blocks--most of them special forgings or castings--the ,morane gear simply requires two short laminated skids1 four ash struts1 and some sheet steel4 ,the laminated skids are built up of three boards each of #e_/h by #b-;inch ash1 #c #a_/b feet long4 ,these must be glued under heavy pressure in forms giving the proper curve at the front end4 ,when they are taken from the press1 three or four #a_/b-;inch holes should be bored at equal distances along the center line and wood pins driven in2 these help in retaining the curve4 ,the finished size of the skids should be #a #c_/d by #a #c_/d inches4 ,four ash struts #a #a_/d by #b #a_/b inches support the fuselage4 ,they are rounded off to an oval shape except at the ends1 where they are attached to the skids and the fuselage beams with clamps of #a_/af inch sheet steel4 ,the ends of the struts must be beveled off carefully to make a good fit2 they spread out #ae degrees from the vertical1 and the rear pair have a backward slant of #cj degrees from vertical4 ,additional fuselage struts must be provided at the front end of the fuselage to take the place of the struts and beams of the ,bleriot running gear4 ,the two vertical struts at the extreme front end may be of the same #a #a_/d- by #b #a_/b-;inch ash used in the running gear1 planed down to #a #c_/af inches thick to match the thickness of the fuselage beams4 ,the horizontal struts should be #a #c_/af by #a #c_/d inches4 ,the wheels run on the ends of an axle tube1 and usually have plain bearings4 ,the standard size bore of the hub is #ae_/af inch1 and the axle tube should be #ae_/af inch diameter by #aa gauge4 ,the tube also has loosely mounted on it two spools to carry the rubber band springs4 ,these are made of #b #a_/d-;inch lengths of #a #c_/h-;inch tubing1 with walls of sufficient thickness to make an easy sliding fit on the axle tube4 ,to the ends of each length of tube are brazed #b #a_/b-;inch washers of #c_/af inch steel1 completing the spool4 ,the ends of the rubber bands are carried on rollers of #c_/d-;inch1 #af-;gauge tubing1 fastened to the skids by fittings bent up from #c_/af-;inch sheet steel4 ,each fitting is bolted to the skid with two #c_/h-;inch bolts4 ,some arrangement must now be made to keep the axle centered under the machine1 as the rubber bands will not take any sidewise strain4 ,a clamp of heavy sheet steel should be made to fit over the axle at its center1 and from this heavy wires or cables run to the bottom ends of the forward struts4 ,these wires may be provided with stiff coil springs1 if it is desired to allow a little sidewise movement4 ,illustration3 ,fig4 #cf4 ,details of ,bleriot ,inverse ,curve ,tail ,new ,bleriot ,inverse ,curve ,tail4 ,some of the latest ,bleriot machines have a new tall which seems to add considerable to their speed4 ,it consists of a fixed tail1 ,fig4 #cf1 nearly as large as the old-style tail and elevators combined1 with two elevator flaps hinged to its rear edge4 ,the peculiarity of these elevators1 from which the tail gets its name1 is that the curve is concave above and convex below--at first glance seeming to have been attached upside down4 ,in this construction1 the #a-;inch1 #bj-;gauge tube1 which formerly passed through the center of the tail1 now runs along the rear edge1 being held on by strips of #a_/b- by #a_/af-;inch steel bent into 99,u99-shape and fastened with screws or bolts to the ribs4 ,similar strips attach the elevators to the tube1 but these strips are bolted to the tube4 ,the construction is otherwise like that previously described4 ,it is said that fitting this tail to a ,bleriot in place of the old-style tail adds #e miles an hour to the speed1 without any other changes being made4 ,another slight change which distinguishes the newer ,bleriots is in the overhead frame1 which now consists of a single inverted 99,v99 instead of two 99,v99's connected by a horizontal tube4 ,the single 99,v99 is set slightly back of the main wing beam1 and is higher and1 of course1 of heavier tubing than in the previous construction4 ,its top should stand #b feet #f inches above the fuselage1 and the tubing should be #a inch #ah gauge4 ,it also requires four truss wires1 two running to the front end of the fuselage and two to the struts to which the rear wing beams are attached4 ,all of the wires on the upper side of the wings converge to one point at the top of this 99,v991 the wires from the wing beams1 of course1 passing over pulleys4 ,these variations from the form already described may be of interest to those who wish to have their machines up-to-date in every detail1 but they are by no means essential4 ,hundreds of the old-style ,bleriots are flying every day and giving perfect satisfaction4 ,,art ,,of ,,flying ,knowledge of the science of aeronautics and ability to fly are two totally different things4 ,long-continued study of the problem from its scientific side enabled the ,wright ,brothers to learn how to build a machine that would fly1 but it did not teach them how to fly with it4 ,that came as the result of persistent attempts at flying itself4 ,a study of the theoretic laws of balancing does not form a good foundation for learning how to ride a bicycle--practice with the actual machine is the only road to success4 ,the best evidence of this is to be found in the fact that several of the most successful aviators today have but a slight knowledge of the science of aeronautics4 ,they are not particularly well versed in what makes flight possible1 but they know how to fly because they have learned it in actual practice4 ,reference to the early work of the ,wright ,brothers shows that during a period of several years they spent a large part of their time in actual experiments in the air1 and it was not until these had proved entirely satisfactory that they attempted to build a power-driven machine4 99,methods ,used in ,aviation ,schools994 ,aviation schools are springing up all over this country and there are a number of well-established institutions of this kind abroad4 ,in the course of instruction1 the student must first learn the use of the various controls on a dummy machine4 ,in the case of an ,english school1 this dummy1 ,fig4 #cg1 is a motorless aeroplane mounted on a universally-jointed support so as to swing about a pivot as desired4 ,this is employed for the purpose of familiarizing the beginner with the means of maintaining equilibrium in the air4 ,illustration3 ,fig4 #cg4 ,monoplane ,dummy ,used for ,practice in ,aviation ,school ,illustration3 ,fig4 #ch4 ,aerocycle with ,treadle ,power for ,practice ,work ,a ,french school1 on the other hand1 employs a wingless machine1 which is otherwise complete1 as it consists of a regulation chassis with motor and propeller1 all steering and elevating controls4 ,on this1 the student may practice what has come to be familiarly known as grass-cutting1 to his heart's content1 without any danger of the machine taking to the air unexpectedly1 as has frequently been the case where first attempts have been made on a full-fledged machine4 ,usually1 most of such attempts result disastrously1 often destroying in a moment the result of months of work in building the machine4 ,illustration3 ,fig4 #ci4 ,voisin ,biplane with ,double ,control for ,teaching ,beginners ,a ,french aerocycle1 ,fig4 #ch1 a comparatively inexpensive machine1 is also useful for practice in balancing and in short1 low flights4 ,the ,french apparatus in question may accordingly be considered an advance1 not only over the ,english machine1 even of the type shown in ,fig4 #ci1 which has a double control1 and is especially designed for the teaching of beginners1 but very much over the practice of attempting to actually fly for the first time in a strange machine1 as it provides the necessary practice in the handling of the motor and the lateral steering4 ,the machine can make high speed over the ground1 but is perfectly safe for the beginner1 as it is incapable of rising4 ,having gone through the stages represented by either of these contrivances1 the best course for the learner to follow is to try gliding1 taking short glides to attain the ability to quickly meet varying conditions of the atmosphere4 ,the fact that these glides are of extremely short duration at first need not be discouraging when it is recalled that1 after several years of work1 the ,wright ,brothers considered that great progress had been made when1 in #aijb1 they were able to make glides of #bf seconds4 ,during six days of the practice season of that year1 they made #cge gliding flights of various distances1 most of them comparatively short1 but each one of value in familiarizing the glider with the conditions to be met4 ,it is not material whether gliding or manipulation of the control levers is taken up first1 as both should be mastered as far as possible before attempting to fly a regular machine4 99,use of the ,elevating ,plane994 ,so many things are necessary to the control of an aeroplane that thinking becomes entirely too slow a process--the aviator must be endowed with something approaching the instinct of the bird2 he must be so familiar with his machine and its peculiarities that a large part of the work of controlling it is the result of subconscious movement4 ,the control levers of many machines are so arranged that this subconscious movement on the part of the aviator directly operates the balancing mechanism4 ,there is no time to think4 ,when a machine rises from the ground1 facing the wind as it should1 its path of flight should be a gradual upward inclination1 this being something difficult to accomplish at first1 owing to the sensitiveness of the elevating rudder1 the tendency almost invariably being to give the latter too great an angle of incidence4 ,at this stage1 the maximum velocity of flight has not yet been attained and care must be taken to keep the angle of ascent small4 ,otherwise1 the power of the engine1 which may not have reached its maximum1 would not be sufficient to cause the machine to ascend an inclined path at the starting speed4 ,if the speed of flight be reduced by the increased resistance at this point1 the whole machine will slide back in the air1 and if a sudden gust of wind happens to coincide with the attempt to rise at too great an angle1 there is danger of it being blown over backward4 ,where the machine is just leaving the ground and the elevator has been set at an excessive angle1 the rear end of the skids or the tail may slap the ground hard and break off1 or they will impose so much resistance upon its movement by scraping over the turf that the machine can not attain its soaring speed4 ,it must be borne in mind1 of course1 that remarks such as the present can be only of the most general nature1 every type of machine having its own peculiarities--in some instances1 the extreme opposite of those characterizing similar machines4 ,for example1 in the ,voisin #aiaj type1 the very large and powerful light tail tends to lift before the main planes1 and if this be not counteracted1 the whole machine may turn up on its end4 ,in order to offset this tendency1 the elevator must be raised so as to keep sufficient pressure beneath it2 the moment of this pressure about the center of gravity must be at least equal to the pressure under the tail planes about the center of gravity of the machine1 or the tail will rise unduly in the air4 ,at least that is the theory of it--naturally1 only practice with that particular machine would suffice to enable an aviator to familiarize himself with that particular peculiarity4 ,again1 some machines are tail heavy4 ,but there is great difficulty in even approximating the degree of relative motion1 for which reason it has been suggested1 under ,accidents and ,their ,lessons1 that a gradometer1 or small spirit level1 in plain sight of the aviator1 should form part of the equipment of every machine4 ,the ,wrights long ago adopted the expedient of attaching a strip of ribbon to the elevator to provide an indication of motion relative to the wind4 99,aeroplane in ,flight994 ,the sensation of motion after the machine leaves the ground is almost imperceptible1 and it is likewise extremely difficult to tell at just what moment the aeroplane ceases running on the solid ground and takes to the air4 ,there is a feeling of exhilaration but very little of motion4 ,whereas #dj miles an hour over the ground1 particularly in an automobile1 brings with it a lively appreciation of the speed of travel1 the same speed in an aeroplane is a very gentle motion when high above the ground4 ,if there be no objects close at hand1 with which to compare the speed1 the sense of motion is almost entirely lost4 99,center of ,gravity994 ,the static balance of a machine should be carefully tried before commencing to fly1 and particularly that of a biplane of the ,wright type1 in which the aviator sits behind the engine4 ,when provision is made for carrying a passenger1 his seat is placed in the center line of the machine1 so that his presence or absence does not materially affect the question of lateral balance4 ,as men are not all of the same weight1 in cases in which the aviator only partly balances the engine about the center line1 his weight being insufficient for the purpose1 extra weights should be placed on the wing tip at the lightest end until the true balance is secured1 otherwise a permanent warping1 or gauchissement as the ,french term it1 is required at this side in order to keep the machine on an even keel4 ,in other words1 the machine will carry what sailors term a port helm where the left side of the machine is lighter than the right1 and vice versa1 and it will be necessary to keep the rudder over to that side slightly during the entire flight to counteract this tendency4 ,in aeroplanes fitted with tails1 the center of gravity is usually in the vicinity of the trailing edge of the main planes and1 of course1 should be on the center line of the machine4 ,the center of gravity of the aviator on a monoplane should approximately coincide with that of the machine4 ,if this be not the case1 the stabilizers or the elevator must be permanently set to produce longitudinal balance4 ,much downward set1 or the increase of the angle of incidence of the tail1 will create undue resistance to flight and should be avoided when possible by bringing the weight farther forward4 ,the center of pressure should coincide with the center of gravity1 and balance will result4 ,before even ground work is attempted1 the position of the center of gravity should be determined in the manner shown in ,fig4 #dj1 the approximate location for four types of machines being shown4 ,at what point the machine must be suspended1 so that it can tip only frontward and backward and be evenly balanced1 is a question that must be answered in order to ascertain the probability of the machine's pitching forward whenever mud1 grass1 or rough ground is encountered in alighting4 ,if the center of gravity should lie in front of the axles of the ground wheels in a machine of the ,farman type1 trouble is sure to follow4 ,always consider the relation of the center of gravity to the wheels1 in order that you may gain some idea of the distribution of the weight on the running gear when the machine is tipped forward #aj degrees4 ,if the wheels are not forward far enough there will be trouble in running on the ground4 ,the elevators must correct whatever variance there may be from the correct center of gravity and position of the wheels1 and the manipulation of the elevators for that purpose requires skill4 ,if the tail be very heavy1 the elevator may not be able to counteract that defect4 ,illustration3 ,fig4 #dj4 ,method of ,determining ,center of ,gravity of ,different ,types of ,machines ,the position of the center of gravity of a machine in regard to lateral stability in flight is a matter of far greater importance than untried aviators realize4 ,having it too low is quite as bad as too high1 as in either case there is a tendency to upset4 ,although the dihedral angle is considered wasteful of power1 it seems to do more to secure inherent stability than any other device4 ,devices for maintaining stability automatically are to be frowned upon in the present state of the art4 ,the sensitive perception and quick response which come with intimate knowledge of a machine's peculiarities1 are at present worth more than gyroscopes and pendulums4 ,to acquire this intimate knowledge1 the aviator must familiarize himself thoroughly with the machine2 he must become so accustomed to controls that he and the machine are literally one4 ,a practiced bicycle rider does not have to think about balance1 neither does the practiced aviator1 yet he must always be prepared to meet motor stoppages1 unusual air disturbances1 and breakages4 ,a leap from the ground directly into the air1 without preliminary practice1 means certain accident1 to put it mildly4 99,center of ,pressure994 ,but although the center of gravity remains approximately constant1 the center of pressure is continually varying and is never constant for many seconds4 ,the center of pressure on an aerocurve constructed to ,phillips' design1 ,fig4 #da1 is about one-third of the chord from the leading edge of the plane under normal conditions1 i4e41 when the angle of incidence is about #h degrees between the direction of motion of the plane and that of the air4 ,at the moment this angle is increased the center of pressure moves toward the rear1 and vice versa4 ,the center of gravity must be moved to coincide with this new position1 or the center of pressure must be artificially restored by the use of supplementary planes or elevators1 moving in a contrary direction4 ,a forward movement of the center of pressure tends to lower the tail of the machine1 when the intensity of the pressure is unchanged1 and to counterbalance this the rear elevator must have its angle of incidence increased in order to increase the lift at the rear of the machine1 or it will slide down backward4 ,the alternative to be adopted in case of temporary lack of engine power is to decrease the angle of the elevator and allow the aeroplane to sweep downward1 thus gaining momentum4 ,the increase of speed will then be sufficient probably to enable the machine to continue in a horizontal flight1 when the center of pressure is again restored to its normal position4 ,illustration3 ,fig4 #da4 ,aerocurve of ,phillip's ,design 99,ground ,practice994 ,first of all1 the aviator should familiarize himself with his seat for it is from that place that he must judge wind effects1 vibration1 motor trouble1 and the thousand and one little creaks and hums that will ultimately mean so much to him4 ,not until he has thoroughly accustomed himself to his seat1 should he try to run along the ground4 ,this done1 hours should be spent running up and down and around the field to learn the use of the rudder1 particularly on rough ground4 ,the runs should be straight so that when the time comes to leap into the air1 the aviator may be sure that he is on an even keel1 and flying straightaway4 ,in order to prevent the possibility of leaving the ground unexpectedly in practice1 trials should be made only in calm weather and with the motor well throttled down so that the machine will be reduced to a speed of not more than #ae miles per hour4 ,after a time this may be increased to #bj1 but the latter is the maximum for ground practice1 as the machine will rise at speeds slightly exceeding this4 ,in these practice rims on the ground1 the student should learn to gauge the rush of air against his face1 as when aloft his best gauge will be the wind pressure on his cheeks1 as that will tell him whether he is moving with sufficient speed to keep up or not4 ,it will also tell him ultimately whether he is moving along the ground fast enough to leap up4 ,illustration3 ,,vedrines1 ,,one ,,of ,,the ,,most ,,famous ,,and ,,successful ,,of ,,european ,,aeroplane ,,pilots1 ,,seated ,,in ,a ,,deperdussin ,,monoplane ,illustration3 ,,airship ,,crossing ,,one ,,of ,,the ,,national ,,roads ,,in ,,rural ,,france ,this ,photograph ,protected by ,international ,copyright ,in this stage of experimenting on the ground1 the elevator is kept neutral as far as possible4 ,with increasing skill its use may be ventured1 but only sparingly1 for it takes very little to lift the machine from the ground with a speed in excess of #bj miles per hour4 ,it will soon be discovered that the elevator can be used as a brake to prevent pitching forward4 ,the tail elevators on the ,farman or ,bleriot running gear are very effective owing to the blast of the propeller1 even when the main planes are not moving forward at lifting speed4 ,with the ,curtiss type of running gear and a front elevator only1 it is often possible at #ah to #bj miles per hour to raise the front wheel off the ground for a second or two--facts which indicate that at #be to #bh miles per hour1 the elevator is far more effective4 99,first ,flight994 ,the first actual flight should be confined to a short trip parallel to the ground and not more than one or two feet above it4 ,at first1 the student should see how close he can fly to the ground without actually touching it1 which he can do by gradually increasing his forward speed4 ,this must be done in an absolute calm as an appreciable amount of wind will bring in too many other factors for the student to master at so early a stage4 ,this practice should be continued in calm air until short1 straight flights can be made a foot or two from the ground with the motor wide open4 ,if it be found that the machine barely flies straightaway with the full power of the motor1 the latter is either badly out of adjustment1 or a more powerful engine is required4 ,in an under-powered machine turning would be suicidal4 ,moreover1 the resistance encountered in the air is greater than on the ground and may be such that the speed is not sufficient for sustentation4 ,fig4 #db1 7a7 and 7b71 show why it is possible to run along the ground faster than it is possible to travel in the air1 under certain conditions1 and why the ground can be left at low speed4 ,if it were possible to drive a machine with such enormous projected areas as ,,bb1 shown in ,fig4 #db 7b71 a man could fly slowly for an indefinite period4 ,but the projected area is greater than the air displaced by the propeller1 and it is impossible to fly except with a moderate angle of incidence1 giving projected areas ,a ,a1 ,fig4 #db 7a74 ,the student1 as he increases in skill1 may venture to a height of #aj feet1 which should be maintained as accurately as before1 and after making a run of #ajj yards1 the machine should be pointed down1 but ever so slightly4 ,the wind pressure on the face immediately becomes greater4 ,within a foot or two of the ground the motor should be cut off or throttled4 ,this should be tried ten or fifteen times1 and the height increased to #cj or #dj feet1 in order that the student may familiarize himself with the sensation of coasting4 ,at the end of each glide the machine will seem to become more responsive1 as indeed it does1 for gliding down greatly increases the efficiency of the elevator and other controls1 because of the increased speed4 ,gliding down steep angles is often the aviator's salvation in a tight place1 particularly when the motor fails1 a side gust threatens or an air pocket is encountered4 ,illustration3 ,fig4 #db4 ,diagrams ,showing ,greater ,projected ,area of ,main ,plane when ,running along ,ground 99,warping the ,wings994 ,when sufficient confidence has been attained at a height of #cj to #dj feet1 the ailerons or warping devices may be tried judiciously4 ,here the intention should be to correct any tendency to side tipping1 and not purposely to incline the machine as far as possible without actually causing a wreck4 ,the use of the lateral control may cause the machine to swerve a little1 but that may be ignored4 ,before landing1 a straight course should be taken so that the machine will always come down on an even keel4 ,with increasing practice1 the student may fly higher1 but always with the understanding that there is a limit to the angle of incidence4 ,an automobile is retarded when it strikes a short1 steep hill2 so is an aeroplane4 ,no aeroplane has yet been built that can take a steep angle and climb right up that grade continuously4 ,altitude is reached by a series of small steps and at comparatively low angles1 as unless the course is straightened out at regular intervals1 a machine will lose its speed and tend to plunge tail first1 just as is the case when an attempt is made to rise from the ground at too sharp an angle4 ,in warping the wings an increase of lift imparted to one wing of the machine is produced by increasing the angle of incidence of the whole or part of the wing1 or by an increase of pressure under that wing1 and will tend to cause that side of the machine to rise and the other side to lower1 the result being that the machine will be liable to slide through the air diagonally4 ,in the majority of aeroplanes there are no fins or keels to counteract this movement1 and lateral stability must be restored by artificially increasing the lift of the depressed wing4 ,this can be done by warping1 or lowering the trailing edge of the depressed wing and increasing its lift1 and simultaneously raising the trailing edge of the other wing1 thus decreasing the angle of incidence of the latter and reducing its lifting effect4 ,this applies to flight on a straight course1 whatever the cause may be that tends to upset lateral stability4 ,it will be seen1 therefore1 that the center of gravity remains constant and the center of pressure must be manipulated to restore stability4 ,this manipulation is much more rapid and positive than the alteration of the center of gravity by the movement of the aviator's body resorted to in the early gliding flights of pioneer experimenters4 99,making a ,turn994 ,the first turn should be made over a large field and the diameter of the turn should be at least half a mile4 ,the height should be not less than #ej feet4 ,after that level has been maintained1 the rudder should be moved very gingerly4 ,the machine will lean in almost immediately1 because the outer end travels at a higher speed than the inner and therefore has a greater lift4 ,warping or working the ailerons should be resorted to as a means of counteracting this tendency1 and the rudder swung to the opposite direction1 if necessary4 ,it is obvious that if the rudder will cause the machine to bank when swung in one direction1 it will right the machine again when swung in the opposite direction4 ,it is even possible to turn the machine on an even keel by anticipating the banking1 simply by correctly using the rudder1 which was necessary in the old ,voisin machine flown by ,farman in #aijh1 because it had no mechanical lateral control4 ,the student should learn the correct angle of banking1 i4e4 the angle at which the machine will neither skid nor slide down and which is most economical of power because it requires less use of the lateral controls4 ,the necessity of feeling the air is greater in turning than in any other phase of flying4 ,by feeling the air is meant the ability to meet any contingency intuitively and not until this is acquired can the student become an expert aviator4 ,when it has been acquired1 safe flying is assured and is dependent only upon the integrity of the planes1 motor1 and controls4 ,by using the rudder discreetly and by banking simply far enough to partially offset the centrifugal force of turning1 the use of the lateral control will not be necessary in still air4 ,even too short a turn can be corrected by a quick use of the rudder4 ,the peculiarities existing between different types of monoplanes become even more marked than between the biplane and the monoplane4 ,for example1 in piloting a ,bleriot monoplane1 ,fig4 #dc1 it is necessary to take into account the effect of the engine torque4 ,as the engine rotates in a right-hand direction1 from the point of view of the pilot1 the left wing tends to rise in the air1 owing to the depression of the right side of the machine4 ,the machine also tends to turn to the right1 and this must be counteracted by putting the rudder over to the left4 ,an aeroplane answers its controls with comparative slowness1 with the exception1 perhaps1 of the ,wright machine1 which is noted for its sensitive and quick response to every movement of the levers4 ,all control movements must1 therefore1 be very gentle1 as the behavior of an aeroplane is more like that of a boat than that of an automobile4 ,the action of the elevator has already been described1 and it is1 perhaps1 the most difficult of all the controls to manipulate1 in that it requires the exercise of a new sense4 ,the direction rudder is naturally a more familiar type of control1 and in action is similar to the rudder of a boat4 ,the torque of the motor renders it advisable for a novice to turn his machine to the right1 if a right-hand propeller be used1 and vice versa4 ,if two propellers1 turning in opposite directions1 are employed1 as in the ,wright biplane1 there is no inequality from the torque of the motor4 ,since torque is not noticeable in straight flying1 straightening out again will always serve the student when he finds himself in trouble on a turn4 ,when the use of the rudders and ailerons has reduced the speed1 a downward glide will increase it again1 and if the motor should stop on a turn1 such a downward glide is immediately imperative4 ,when the machine is thus gliding1 a change in the fore-and-aft balance becomes at once apparent1 because the blast of the propeller no longer acts on the tail1 and the elevator must then be used with greater amplitude to obtain the same effect4 ,illustration3 ,fig4 #dc4 ,making a ,start with ,bleriot ,monoplane ,only by constant practice in calm air can the student familiarize himself with exactly the amount of warping and rudder control to employ to property offset the lowering of the inner wing in rounding a turn4 ,if this be not corrected1 the whole machine tends to bank excessively and will be apt to slide downward in a diagonal direction1 ,fig4 #dd4 ,this is a perilous position for the aviator and must be guarded against by the manipulation of the warping control so as to increase the lift of the inner wing of a biplane1 at the same time1 employing the rudder to counteract this tendency4 ,the use of the rudder is of even greater importance on the monoplane1 as1 in this case1 warping the inner wing tends to direct the whole machine downward instead of raising the inner wing itself4 ,several bad accidents have resulted from monoplanes refusing to respond to the warping of the inner wing when making a turn4 ,in such machines1 the rudder must be practically always employed in connection with the warping of the wings in order to keep the machine on an even keel1 although the controls may not actually be interconnected1 this being one of the grounds on which foreign manufacturers are trying to make use of the ,wright principle1 without infringing the ,wright patents1 as while they employ warping in connection with the simultaneous use of the rudder1 the controls are not attached to the same lever as in the ,wright machine4 ,illustration3 ,fig4 #dd4 ,an ,aeroplane ,banking as it ,rounds a ,pylon ,lateral resistance must also be taken into consideration in turning1 otherwise the machine1 if kept on an even keel1 will tend to skid through the air and turn about its center of gravity as a pivot4 ,in the case of an automobile1 the resistance to lateral displacement is great1 though on a greasy surface it may be small1 as when the machine skids sideways1 a suitable banking of the road being necessary to prevent this on turns4 ,many hold that the banking of the aeroplane on turns is only the direct effect of the turning itself1 but the fallacy of this will be apparent upon a consideration of the law of centrifugal force4 ,it is obvious that to make a turn1 some force must be imparted to the machine to counteract the effect of the centrifugal force upon the machine as a whole4 ,and as the sidewise projection of the machine is small1 a compensating force must be introduced4 ,this can be done only by previously banking up the machine on the outer wing1 so that the pressure of the air under the main plane can counteract the tendency to lateral displacement4 ,the force then acting under the planes is in a diagonal direction1 and the angle at which it is inclined vertically depends upon the banking of the planes1 it being normal to their greater dimension4 ,this force can be resolved into two forces1 one perpendicular and one horizontal1 the magnitude of each being dependent upon the degree of banking4 ,when the speed of the machine is higher1 the amount of banking must be greater in order to increase the value of the horizontal component in proportion to the increase of the value of the centrifugal force at the higher speed1 in spite of the fact that the forces acting under the planes are also greater due to the higher speed4 ,as the curve commences1 the rudder being put over1 the difference of the pressures on the two wings1 owing to their different flying speeds comes into account1 as already explained1 and care must be taken that the banking does not increase abnormally4 ,when the turn is completed1 the rudder is straightened and the machine is again brought to an even keel with the aid of the wing-warping control1 or the ailerons4 ,the effect of a reverse warping to prevent excessive banking1 lowering the inside wing tip incidentally1 puts a slight drag on that wing and assists in the action of turning1 as does also the provision of small vertical planes between the elevator planes of the original ,wright machine4 ,since the adoption of the headless type1 these surfaces are placed between the forward ends of the skids and the braces leading down to them4 ,in making a turn1 say1 to the left1 the outside or right-hand wing is first raised by lowering the wing tip on that side and the rudder is then put over to the left4 ,when the correct amount of banking is acquired1 the wing tip is restored to its normal position1 and probably the left wing tip may have to be lowered slightly to increase the lift on that side owing to its reduced speed4 ,when the turn is completed1 the rudder is straightened out and the left wing tip lowered to restore the machine to an even keel4 ,both ,glenn ,curtiss in this country and ,r4 ,e4 ,pelterie in ,france have shown that it is possible to maneuver without using the rudder at all1 the ailerons or wing tips alone being relied upon for this purpose4 ,before flights in other than calm air are attempted1 much practice is required4 ,the machine must be inspected over and over again1 and the wind variations studied with a watchful eye4 ,not until this familiarity with machine and atmosphere be acquired should flying in a wind be attempted4 ,to the man on the ground1 wind is simply air moving horizontally1 but to the man in the air it is quite different4 ,not only must he consider horizontal movement1 but vertical draughts and vortices as well4 ,a rising current of air lifts a machine1 a downward current depresses it1 and he must learn to take advantage of the former as the birds do4 ,horizontal currents affect forward speed over the ground2 swirls and vortices create inequalities in wind pressure on the planes and disturb lateral balance4 ,familiarity with all these atmospheric conditions can be acquired only after long practice4 ,against every tree1 house1 hill1 fence1 and hedge beats an invisible surf of air2 upward currents on one side and downward on the other4 ,the upward draught is not usually dangerous1 for it simply lifts the machine2 but the down draught will cause it to drop4 ,a swift downward glide under the full power of the motor must then be made1 to increase the forward speed and consequently the lift4 ,this explains why it is dangerous to fly near the ground in a wind2 likewise why the beginner should never attempt flying at first in anything but a dead calm4 ,turning in a ,wind4 ,when turning in a wind1 two velocities must be borne in mind1 that of the machine relative to the air and that relative to the earth4 ,the former is limited at its lower value to that of the flying speed of the machine1 and the latter must be considered on account of the momentum of the machine as a whole4 ,change of momentum is a matter of horse-power and weight and is the governing factor in flying in a wind on a circular course4 ,suppose the flying speed of a machine is a minimum of #cj miles an hour relative to the air1 and a wind of #bj miles an hour is blowing4 ,the actual speed of the machine relative to the earth in flying against the wind will be #aj miles an hour4 ,if it be desired to turn down the wind1 the speed of the machine relative to the earth must be increased from #aj miles to #ej miles an hour during the turn and a corresponding change of momentum must be overcome4 ,there are two ways of accomplishing this1 either by speeding up the motor to give the maximum power1 or by rising just previous to making the turn and then sweeping down as the turn is made1 thus utilizing the acceleration due to gravity to assist the motor4 ,the wind's velocity will assist the machine also and during the turn it will make considerable leeway1 a small amount of which is deducted to counteract the centrifugal force of the machine4 ,turning in a contrary direction1 i4e41 up into the wind when running with it1 requires considerable skill1 as when flying #ej miles an hour1 the tendency on rounding a corner into a #bj-mile-an-hour wind would be for the machine to rise rapidly in the air4 ,the centrifugal force at such a speed is also considerable1 causing the machine to make much leeway with the wind during the turn4 ,turning under such circumstances should be commenced early1 particularly if there are any obstructions in the vicinity1 and considerable skill should be acquired before an attempt is made to fly in such a wind4 99,starting and ,landing994 ,a machine should always be started and landed in the teeth of the wind1 and no one but the most experienced aviators can afford to disregard this advice1 certainly not the novice4 ,the precaution is necessary because in landing the machine should always travel straight ahead without the possibility of lurching and consequently breaking a wing1 as frequently happens4 ,contact with the ground is necessarily made at a time when the machine is traveling over it at a speed of #cj to #dj miles per hour and skidding sideways at #aj to #ae miles per hour1 all circumstances which tend to wreck an aeroplane4 99,planning a ,flight994 ,it is easy to lose one's way in the air4 ,for that reason it is best to follow the ,wright idea of starting out with a definite plan1 and of landing in some predetermined spot1 as aimless wandering about may prove disastrous to the inexperienced aviator1 he may forget which way the wind was blowing1 or how much fuel he had1 or the character of the ground beneath him4 ,should the motor stop1 he may make an all too hasty decision in landing4 ,it is an easy matter to lose one's bearings in the air1 not only because the vehicle is completely immersed in the medium in which it is traveling1 but also because the earth assumes a new aspect from the seat of an aeroplane4 ,cecil ,grace was one of those who lost his bearings and1 as a consequence1 his life4 ,ordinary winds blowing over a level country can be negotiated with comparative safety4 ,not so the puffy wind4 ,to cope with that1 constant vigilance is required1 particularly in turning4 ,in a circular flight in a steady wind1 the only apparent effect is that the earth is swept over faster in one direction than in the other4 ,before a cross-country flight is attempted1 the starting field should be circled over at a great height1 as not until then may the long distance flight be started in safety4 ,cross-country flying is1 of course1 fascinating1 and it is a sore temptation1 at an altitude of a few hundred feet1 to throw off all caution and fly off over that strange country below1 which is1 indeed1 a new land as viewed from aloft4 ,to quote a professional aviator3 ,here the greatest self-restraint must be exercised4 ,not until the necessary practice has been acquired1 not until the right kind of confidence has been gained1 may one of these trips be attempted1 and then only after it has been properly planned4 99,training the ,professional ,aviator994 ,look back over the achievements in the air during the comparatively short time that man has actually been flying1 and it will be noted that the beginners1 burning up with the enthusiasm of the novice1 have performed the most spectacular feats and flown with the greatest fearlessness4 ,curtiss was comparatively new at aviation when he won the ,gordon-,bennett at ,rheims in #aiji4 ,john ,b4 ,moisant1 the sixth time he ever went up in an aeroplane1 flew from ,paris to ,london with a #ahg-pound passenger and #cjb pounds of fuel1 oil1 and spare parts4 ,hamilton made his successful flight from ,new ,york to ,philadelphia and return when he was hardly more than a novice1 while ,atwood's great flights from ,st4 ,louis to ,new ,york and ,boston to ,washington were made before his name had become known1 and ,beachey had been flying only a few months when he broke the world's altitude record at ,chicago1 while more recent achievements1 notably ,dixon's flight across the ,rockies1 have emphasized the work of the beginner4 ,all of this substantiates the belief held at every aviation headquarters in the country--namely1 that the older men already in aviation may improve the art by executive ability and scientific experiments1 but most of them will degenerate as flyers4 ,beyond a certain point1 frequency of flight does not necessarily create a feeling of confidence and safety2 rather it brings a fuller appreciation of the dangers1 and the men who best know how to fly are most content to stay upon the ground4 ,professional aviators are drawn from every walk of life1 but trick bicycle performers1 acrobats1 parachute jumpers1 and racing automobile drivers make the most promising applicants4 ,by a kind of sixth sense1 both the ,wrights and ,curtiss weed out the promising ones after a brief examination4 ,they select men who have an almost intuitive sense of balance4 ,most of these1 provided they have nerve1 have in them the stuff of which aviators are made1 even though they may have had no experience in any line akin to aviation4 ,neither ,curtiss nor the ,wrights will accept women under any condition4 ,the ,moisant school does not share this discrimination and trained three women for pilot's licenses during #aiaa4 ,curtiss and the ,wrights are keen in their realization that recklessness is pulling a wing feather from aviation every time a man is killed1 and they are doing their utmost to promote conservatism4 ,curtiss said in an interview3 ,i do not encourage and never have encouraged fancy flying4 ,i regard the spectacular gyrations of several aviators ,i know as foolhardy and unnecessary4 ,i do not believe that fancy or trick flying demonstrates anything except an unlimited amount of a certain kind of nerve and perhaps the possibilities of what is valueless--aerial acrobatics4 ,some aviators develop the sense of balance very rapidly1 while others acquire it only after long practice4 ,it may be developed to a large extent by going up as a passenger with an experienced man4 ,therefore1 in teaching a beginner1 ,i make it a point to have him make as many trips as possible with someone else operating the machine4 ,in this way the pupil gains confidence1 becomes accustomed to the sensation of flying1 and is soon ready for a flight on his own hook4 ,this is the method used in training army and navy officers to fly4 ,i have never seen novices more cautious and yet more eager to fly than these young officers4 ,they have always learned every detail of their machines before going aloft1 and largely because of this they have developed into great flyers4 ,perhaps it is due to the military bent of their minds2 at any rate1 they have made good almost without exception4 ,,accidents ,,and ,,their ,,lessons 99,press ,reports994 ,whenever an industry1 profession1 or what not1 is prominently before the public1 every event connected with it is regarded as good copy by the daily press4 ,happenings of so insignificant a nature that in any commonplace calling would not be considered worthy of mention at all1 are played up4 ,this is particularly the case with fatalities1 and the eagerness to cater to the morbid streak in human nature has been responsible for the unusual amount of attention devoted to any or all accidents to flying machines1 and more especially where they have a fatal ending4 ,in fact1 this has led to the chronicling of many deaths in the field of aviation that have not happened--some of them where there was not even an accident of any kind4 ,for instance1 in many of the casualty lists published abroad from time to time1 such flyers as ,hamilton1 ,brookins1 and others have figured among those who have been killed1 ever since the date of mishaps that they had months ago4 ,it will be recalled that five years ago1 when the automobile began to assume a very prominent position1 every fatality for which it was responsible was heralded broadcast where deaths caused by other vehicles would not be accorded more than local notice4 ,to a large extent1 this is still true and will probably continue to be the case until the automobile assumes a role in our daily existence as commonplace as the horse-drawn wagon and trolley car4 ,there is undoubtedly ample justification for this and particularly for the editorial comment always accompanying it1 where the number of lives sacrificed to what can be regarded only as criminal recklessness is concerned4 ,still1 the fact that in a city like ,new ,york the truck and the trolley car are responsible for an annual death roll more than twice as large as that caused by the automobile1 does not call for any particular mention4 ,horses and wagons1 we have always had with us1 and the trolley car long since became too commonplace an institution around which to build a sensation4 ,as the most novel and recent of man's accomplishments1 the conquest of the air and everything pertaining to it is a subject on which the public is exceedingly keen for news and nothing appears to be of too trivial import to merit space4 ,where an aviator of any prominence is injured1 or succumbs to an accident1 the event is accorded an amount of attention little short of that given the death of some one prominent in official life4 ,during the four years that aviation has been to the fore1 about #ajd men and one woman have been killed1 not including the deaths of three or four spectators resulting from accidents to aeroplanes1 during this period--i4e41 from the beginning of #aijh to the end of #aiaa4 ,in view of the lack of corroboration in some cases1 the figures are made thus indefinite4 ,naturally most of these deaths have occurred in #aiaj and #aiaa--;in fact1 #ej per cent took place from #aijh to the end of #aiaj1 and the remainder during #aiaa1 since these years were responsible for a far greater development1 and particularly for a greater increase in the number engaged1 than ever before4 ,more was accomplished in these two years than in the entire period intervening between that day in ,december1 #aijc1 when the ,wright ,brothers first succeeded in leaving the ground in a power-driven machine1 and the beginning of #aiaj4 99,fatal ,accidents994 ,conceding that the maximum number mentioned1 #aje1 were killed during the four years in question1 throughout the world1 it will doubtless come as a surprise to many to learn that this is probably not quite twice the number who have succumbed to football accidents during the same time in the ,united ,states alone4 ,authentic statistics place the number thus killed at #ac during #aijh1 #bc in #aiji1 #ad during #aiaj1 and #ag in #aiaa1 or a total of #fg4 ,but we have been playing football for a couple of centuries or more and this is regarded as a matter of course4 ,the death of a football player occurring in some small1 out-of-the-way place would not receive more than local attention1 unless there were other reasons for giving it prominence1 so that1 in all probability1 the statistics in question fall far short of the truth1 rather than otherwise4 ,the object of mentioning this phase of the matter is to place the question of accidents in its true light4 ,that the development of any new art is bound to be attended by numerous mishaps1 many of them fatal1 goes without saying and it is something that can not be ignored4 ,nothing could be worse than attempting to gloss over or belittle the loss of life for which aviation has been responsible and doubtless will continue to be4 ,progress invariably takes its toll and it is more often founded upon failure than unvarying success1 for every accident is a failure1 in a sense1 and every accident carries with it its own lesson4 ,where the cause is apparent1 it gives an indication of the remedy which will bring about the prevention of its recurrence4 ,in other words1 it serves to point out weaknesses and shows what is necessary to overcome them4 ,for that reason alone is the question of accidents taken up here1 as a study of those that have occurred points the way to improvement4 ,table ,,iii gives a resume of the more important fatalities that have resulted from the use of a heavier-than-air machine during the past four years3 ,fatalities greatly increased in number during #aiaa1 but not out of proportion to the greatly augmented number of aviators4 ,with comparatively few exceptions1 however1 the accidents were more or less similar in their nature to those already tabulated1 so that it would be of no particular value to extend the comparison in this manner to cover them4 ,many of the fatalities during that year were not of the aviators themselves1 but of the spectators1 a fact which calls attention to a danger that has not been fully appreciated before4 ,at the start of the ,paris-,madrid race1 the ,french minister of war and another official were killed by a monoplane plunging into the crowd1 and on the same day1 ,may #ba1 #aiaa1 five people were killed at ,odessa1 ,russia1 in the same manner4 ,an unusual type of mishap1 not mentioned in the tabulation and in which three or four aviators lost their lives during #aiaa1 was the burning of the aeroplane in midair1 or the explosion of the gasoline1 setting fire to the wings and either burning the aviator at his post or killing him by the fall4 ,one such accident occurred in ,france in ,september1 another in ,spain two days later1 and a third in ,germany1 in which two men were killed4 ,accidents of an even more unusual nature were the collision of two biplanes in midair at ,st4 ,petersburg1 the collision of a motorcycle with a biplane as it swooped down on a race track1 and the partial wrecking of ,fowler's biplane by a bull upon landing near ,fort ,worth1 ,texas1 but these1 of course1 had no bearing on the design of the machines4 ,apart from those specially referred to1 the great majority of accidents during #aiaa may be ascribed to two or three of the causes detailed in connection with the comparative table4 ,of these1 lack of experience and foolhardiness stand out prominently1 the latter undoubtedly causing the double fatality at ,chicago when two aeroplanes plunged into ,lake ,michigan1 drowning one of the aviators1 while a third machine collapsed in mid-air1 hurling the aviator to his death on the field4 ,careful reading of the reports of a large number of these accidents usually brings to light the statement in attempting to make a quick turn1 or similar phrase1 showing that the moving cause of the accident was due to subjecting the parts of the machine to excessive stresses1 as outlined in the following pages4 99,causes994 ,lack of ,experience4 ,it will be at once noticeable by ,table ,,iii that out of a total of #bh1 no less than #af1 or considerably more than half of the accidents1 were due in one way or another to lack of experience4 ,in other words1 the aviators had not fully complied with the cardinal principle for success in flying upon which the ,wright ,brothers have always laid so much stress1 i4e41 you must first learn to fly before you can attempt to go aloft safely4 ,nothing short of a thorough mastery of the machine can suffice to give the aviator the ability to do the right thing at the right moment1 in the great majority of cases4 ,there will always be occasions when even the most skilled aviator will make errors of judgment and frequently they cost him his life4 ,but this is equally true of every dangerous calling1 whether it be running an automobile1 driving a locomotive1 or doing any of the thousand and one things where the responsibility for his own and other lives is placed in one man's hands and depends to a large extent on his discretion and judgment in cases of emergency1 so that there will be fatalities from this cause as long as man continues to fly4 ,this involves the personal equation that must always be reckoned with4 ,just how many of the accidents that have resulted in the fatalities set forth1 have been due to the fallibility of the operator and for how much the design of the current types of machines is responsible1 would be hard to say4 ,fig4 #de1 for example1 which shows ,h4 ,v4 ,roe in the act of striking the ground in his triplane1 illustrates an accident due to bad design4 ,methods of control will be improved and simplified and made as nearly fool-proof as human ingenuity can accomplish1 but experience in other fields has demonstrated unmistakably that they can never be developed to a point where it is impossible to do the wrong thing4 ,with skill at such a premium in callings of responsibility which involve only conditions that have been familiar for years1 how much more so must it be in the air about which so little is known8 ,consequently1 the real danger is to be found in the personal equation1 just as it is in every other mode of conveyance1 despite the fact that it has been perfected to a point which apparently admits of little further development where safe-guarding it is concerned4 ,illustration3 ,fig4 #de4 ,roe's ,multiplane as it ,struck the ,ground4 ,an ,accident ,due to ,poor ,design ,illustration3 ,fig4 #df4 ,de,lessep's ,machine after ,striking an ,obstruction ,illustration3 ,fig4 #dg4 ,overturned ,monoplane ,due to a ,start in a ,gale 99,obstructions994 ,obstructions are bound to play a prominent part in accidents to any method of conveyance1 but less so in aviation than in any other1 as it is only in rising and alighting that this danger is present4 ,of the two fatal accidents ascribed to this cause1 one resulted from colliding with an obstruction while running along the ground preparatory to rising1 and the other from striking an obstruction in flight1 ,fig4 #df4 ,in view of the numerous cross-country flights that have been made1 trips across cities and the like1 it is to be marveled at that up to the present writing no fatalities have been caused by what the aviator most dreads when leaving the safety of the open field1 that is1 being compelled to make a landing through stoppage of the motor1 whether from a defection or lack of fuel4 ,while no fatalities have as yet to be put down to this ever-present danger in extended flights1 an accident that might have had a fatal termination1 occurred to ,le ,blanc during the competition for the ,gordon-,bennett trophy1 which was the chief event of the ,international ,meet in ,october1 #ajaj1 at ,belmont ,park1 near ,new ,york4 ,le ,blanc and his fellow compatriots who were eligible were all experienced cross-country flyers1 the former having won the ,circuit de ,l',est1 a race around ,france1 and by far the most ambitious of its kind which had been attempted up to that time4 ,they accordingly protested most vigorously against flying over the ,american course to compete for the cup which ,curtiss had captured at ,rheims the year before1 owing to the fact that it presented numerous dangerous obstructions in the form of trees and telegraph poles4 ,but as it was impossible to provide any other convenient five-kilometer circuit 7#c4aa miles7 as called for by the conditions1 the protest was of no avail4 ,after having covered #ai of the #bj laps necessary to complete the distance of #ajj kilometers in time that had never been approached before1 ,le ,blanc was compelled to descend through lack of fuel1 and as he had not risen more than #hj to #ajj feet at any time during the race1 this meant coming down the moment the motor stopped4 ,the result was a collision with a telegraph pole1 breaking it off and wrecking the monoplane1 the aviator fortunately escaping any serious injury4 ,during the same meet ,moisant demolished his ,bleriot monoplane by trying to start in the face of a high wind1 ,figs4 #dg and #dh4 ,illustration3 ,fig4 #dh4 ,view of ,moisant ,monoplane after a ,bad ,spill 99,stopping of ,motor994 ,the mere fact that the motor stops does not necessarily mean a disastrous ending to a flight1 as is very commonly believed1 this having been strikingly illustrated by ,brookins' glide to earth from an altitude of #e1jjj feet with the motor dead1 and ,moisant's glide from an even greater height in ,france4 ,but it does mean a wreck unless a suitable landing place can be reached with the limited ability to control the machine that the aviator has when he can no longer command its power4 ,motors will undoubtedly become more and more reliable as development progresses1 but the human equation--the partly-filled fuel tank1 the loose adjustment that is overlooked before starting1 and a hundred and one things of a similar nature--will always play their role1 so that compulsory landing in unsuitable places will always constitute a source of danger as flights become more and more extended4 99,breakage of ,parts of ,aeroplanes994 ,in studying the foregoing table1 it can only be a source of satisfaction to the intelligent student and believer in aerial navigation1 to note how large a proportion of the accidents is due to the breakage of parts of the machine4 ,this implies a fault in construction1 but not in principle4 ,it reveals the fact that1 in the attempt to secure lightness1 strength has sometimes been sacrificed1 chiefly through lack of appreciation of the stresses to which the machine is subjected in operation4 ,at a time when weight is regarded almost as the paramount factor by so many builders1 it is inevitable that some should err by shaving things too fine4 ,lightness is an absolute necessity and failure to achieve it in every instance without eliminating the factor of safety has been due more to the crude methods of construction and lack of suitable materials1 than any other cause--conditions that are bound to obtain in the early days of any art4 ,construction is improving rapidly1 but progress is bound to be attended with accidents of this nature4 ,the fact that their proportion is greatly diminishing despite the rapidly increasing number of aviators is the best evidence of what is being accomplished4 ,when machines are built with such a high factor of safety in every part that breakage is an almost unheard-of thing1 failures from this cause will have been reduced to an unsurpassable minimum4 99,failure of the ,control ,mechanism994 ,under the general classification ,b1 are included not alone those accidents directly due to breakage of some vital part1 but also those instances in which some element of the control1 such as the elevator1 has become inoperative through jamming4 ,when an accident happens in the air1 it takes place so quickly and the machine is so totally wrecked by falling to the ground1 that it is usually difficult to determine the exact nature of the cause through a subsequent examination of the parts1 so that it can seldom be stated with certainty just what the initial defection consisted of1 though it may be regarded as a foregone conclusion that1 in the case of experienced aviators who have previously demonstrated their ability to cope with all ordinary emergencies1 nothing short of the failure of some vital part could have caused their fall4 ,this was the case with ,johnstone's accident at ,denver--an occurrence illustrating another phase of the personal equation that must be taken into consideration when noting the lessons to be learned from a study of accidents and their causes4 ,it is simply the old1 old story of familiarity breeding contempt--the miner thawing out sticks of dynamite before an open fire4 ,due to the rarefied air of ,denver1 which is at an elevation of more than #e1jjj feet1 ,johnstone had underestimated the braking powers of the air on the machine in landing the day previous and had crashed into a fence1 breaking one of the right outermost struts between the supporting planes4 ,proper regard for safety should naturally have called for its replacement by an entirely new strut1 but conditions at flying meets as at present conducted make quick repairs to damaged machines imperative4 ,the damaged upright was accordingly glued and braced by placing iron rings around it1 the rings themselves being held in place by ordinary nails passing through holes in the iron large enough to let the nail head slip through4 ,the vibration of the motor and the straining of the strut in warping the wings caused the nails to work out of the holes1 permitting the rings to slide out of place as well4 ,johnstone was an accomplished aviator1 much given to the execution of aerial maneuvers only possible to the skilled flyer of quick and ready judgment4 ,but such performances impose excessive stresses on the supporting planes and their braces1 and one of ,johnstone's quick turns caused the repaired struts to collapse through the strain of sharply warping the wing tips on that side4 ,he immediately attempted to restore the balance of the machine by bringing the left wing down with the control1 then tried to force the twisting on the right side1 succeeding momentarily1 and a few seconds later losing all control and crashing to the ground4 ,it appeared to demonstrate that even when disabled an aeroplane is not entirely without support1 but has more or less buoyancy--something which is really more of an optical illusion than anything else due to underestimating the speed at which a body falls from any great height4 ,johnstone's accident was the first of its kind1 in that he fell from a height of about #hjj feet1 during the first #ejj of which he struggled to regain control of the machine1 finally dropping the remaining #cjj feet apparently as so much dead weight4 ,it showed in a most striking manner the vital importance of the struts connecting the supporting surfaces of the biplane1 any damage to them resulting in the crippling of the balancing devices and the end of all aerial support4 99,biplane vs4 ,monoplane994 ,it requires only a glance at ,table ,,iii to show that the greater number of accidents have happened to the biplane1 yet the latter is generally regarded as the safer of the two4 ,prior to ,delagrange's fatal fall in ,january1 #aiaj1 there had been only four fatalities with modern flying machines3 ,selfridge and ,lefebre were killed in ,wright machines1 the latter of ,french manufacture1 ,ferber lost control of his ,voisin biplane1 and ,fernandez was killed flying a biplane of his own design4 ,in one case at least1 that of ,lieutenant ,selfridge1 the accident appears to have been due to the failure of a vital part--the propeller4 ,it has since become customary to cover the tips of propellers for at least a foot or so with fabric tightly fitted and varnished so as to become practically an integral part of the wood4 ,this prevents splintering as well as avoiding the danger of the laminations succumbing to centrifugal force and flying apart4 ,at the extremely high speeds1 particularly at which direct-driven propellers are run1 the stress imposed on the outer portion of the blades by this force is tremendous4 ,in making any attempt to compare the number of accidents to the biplane and the monoplane1 it must also be borne in mind that the former has been in the majority4 ,delagrange's accident offers two special features of technical interest4 ,it was the first fatality to happen with the monoplane and was likewise the first fatal accident which appeared to be distinctly due to a failure of the main structure of the machine4 ,for obvious reasons1 it is usually difficult to definitely fix the cause of an accident1 but in this case there seemed good reason to suppose that the main framing of one of the wings gave way altogether4 ,curiously enough1 ,santos-,dumont had an accident the day following from an exactly similar cause1 the machine plunging to the ground4 ,but with the good fortune that has attended the experimenter throughout his long aerial career1 he was uninjured4 ,it was definitely established that the cause was the fracture of one of the wires taking the upward thrust of the wing4 ,in the case of the biplane1 the top and bottom members are both of wood1 with wooden struts1 the whole being braced with numerous ties of wire4 ,in the monoplane1 however1 the main spars are trussed to a strut below by a comparatively small number of wires4 ,the structure of each wing is1 in fact1 very much like the rigging of a sailboat1 the main spars taking the place of the mast while the wire stays take that of the shrouds1 with this very important difference1 that the mast of the boat is provided with a forestay to take the longitudinal pressure when going head to the wind1 while the wing of an aeroplane often has no such provision1 the longitudinal pressure due to air resistance being taken entirely by the spar4 ,it is quite possible that this had something to do with ,delagrange's accident1 as1 in the effort to make a new record1 his ,bleriot had just been fitted with a very much more powerful motor4 ,in fact1 double that for which the machine was originally designed1 and this was given by the maker as the probable cause of the mishap4 ,as the new motor was of a very light type1 the extra weight1 if any1 was quite a negligible proportion of the total weight of the machine4 ,the vertical stresses on the wings and their supporting wires would1 therefore1 not be materially increased4 ,but as the more powerful engine drove the wings through the air a great deal faster1 the stresses brought upon them by the increased resistance would be substantially augmented and1 unless provision were made for this1 the factor of safety would be much reduced4 ,whether the failure of the wing was actually from longitudinal stress or the breaking of a supporting wire1 as in ,santos-,dumont's case1 will never be known1 but it is quite clear that the question of ample strength to resist longitudinal stresses should be carefully considered1 especially when increasing the power of an existing machine4 ,the question of the most suitable materials and fastenings for the supporting wires is1 moreover1 a matter which requires very careful consideration4 ,in the case of the biplane1 the wires are so numerous that the failure of one1 or even more1 may not endanger the whole structure1 but those of the monoplane are so few that the breaking of but one may mean the loss of the wing4 ,in this respect1 as in others1 the conditions are parallel to the mast of the sailboat4 ,it is only reasonable to expect1 therefore1 that similar materials would be best adapted to the purpose4 ,at present1 however1 the stays of aeroplane wings are almost invariably solid steel wire1 or ribbon1 while marine shrouds are always of stranded wire rope1 solid wire not having been found satisfactory4 ,weight for weight1 the solid wire will stand a greater strain when tried in a testing machine than will the stranded rope1 but practice has always demonstrated that it is not so reliable4 ,the stranded rope never breaks without warning1 and sometimes several of its wires may go before the whole gives way4 ,as the breakage of the strands can be easily seen1 it is possible to replace a damaged stay before it becomes unsafe4 ,in the case of a single wire1 there is nothing to show whether it has deteriorated or not4 ,it seems a doubtful policy to use in an aeroplane what experience has shown not to be good enough for a boat1 and stranded wire cables particularly designed for aeronautic use are now being placed on the market in this country4 99,record ,breaking994 ,striving after records has undoubtedly proved one of the most prolific causes of accident4 ,what is wanted to make the aeroplane of the greatest practical use is that it should be safe and reliable4 ,the tendency of record-breaking machines is the exact opposite of this1 as the weights of all the most essential parts must be cut down to the finest limits possible in order to provide sufficient power and fuel-carrying capacity for the record flight4 ,it is1 in fact1 generally the case in engineering that the design and materials which will give the best results for a short time are essentially different from those which are the most reliable1 and striving after speed records consists simply in disregarding safety and reliability to the greatest extent to which the pilots are willing to risk their necks1 and there is no difficulty in getting men to take practically any risk for the substantial rewards offered4 ,the performance of specially sensational feats in the air is likewise a fertile source of accidents4 ,one noted aviator who has the reputation of being a most conservative and expert operator1 while endeavoring to land within a set space1 made too sudden a turn1 which resulted in the tail of the machine giving way1 precipitating him to the ground4 ,in fact1 the number of failures resulting from abrupt turns shows conclusively that there is too small a factor of safety in the construction1 not because the added weight could not be carried1 but because the extreme lightness alone made possible the stunts for which there is always applause or financial reward4 ,it may seem strange to the man whose only interest in aeronautics is that of an observer1 that so many should be willing to take such unheard-of chances2 that an aeronaut will rise to great heights1 knowing in advance that a vital part of his machine has been deranged1 or is only temporarily repaired2 and that many others will attempt ambitious flights with engines or other parts that have never been tested previously in operation in the air4 ,many young and inexperienced aviators are not content to thoroughly test out each new part on the ground1 or close to it1 but must go aloft at once to do their experimenting1 with the usual result of such foolhardiness4 ,if in other sports safe conditions were absolutely disregarded in this manner--take football as an instance--the resulting fatalities would not be charged against the sport itself4 ,but aviation is so extremely novel and likewise so mysterious to the uninitiated that this is never taken into consideration4 99,excessive ,lightness of ,machines994 ,if1 even at the present early stage of aviation1 machines are being made excessively light for purposes of competition1 it is time that the contest committees of organizations in charge of meetings formulate rules as to the size of engines1 weight of machines1 and similar factors1 so that accidents will not only be reduced to a minimum1 but competition along proper lines will develop types of machines which are useful and not merely racing freaks1 as has already been done in the automobile field4 ,hair-raising performances also should be prohibited1 at least until such time as improvements in the construction of machines make it reasonably certain that they are able1 to withstand the terrific strains imposed upon them in this manner4 ,suddenly attempting to bring the machine to a horizontal plane after a long dip at an appalling angle is an extremely dangerous maneuver1 whether it be taken in the upper air or is one of the now familiar long glides to earth1 which require pulling up short when within a few feet of the ground and after the dropping machine has acquired considerable inertia4 ,the aviator is simply staking his life against the ability of the struts and stays to withstand the terrific stresses imposed upon them every time this is done4 ,as at present constructed1 many of the machines are not sufficiently strong to withstand the utmost in the way of speed and sudden turns which the skilled operator is likely to put on them4 ,they should be made heavier1 or of materials providing greatly increased strength with the same weight4 ,that they can be made heavier without seriously damaging their flying ability has been clearly demonstrated by the numerous flights with one and two passengers1 and on one occasion in which three passengers besides the driver were taken up on an ordinary machine4 ,this was likewise tempting fate by overloading1 but it served to show the possibilities4 ,illustration3 ,fig4 #di4 ,monoplane is ,liable to ,stand on its ,head if ,landing is ,not ,properly ,made 99,landings994 ,then there is a class of accidents for which neither the aviator nor the machine is responsible1 as where spectators have crowded on the field1 causing the flyers to make altogether too sudden or impromptu landings at angles which would otherwise not be considered for a moment4 ,this1 of course1 refers solely to exhibition meets1 and the comparative immunity of cross-country flights from fatal accidents as compared with the latter1 speaks for itself in this respect4 ,in the open1 even the novice seems to be able to pick a safe landing1 especially if high enough to glide some distance before reaching the ground4 ,this brings out the fact that1 as a rule1 the machines are safer in the air--a large part of the danger lies in making a landing4 ,starting places are usually smooth1 but landing places may be the reverse4 ,when alighting directly against the wind1 which is the only safe practice1 most of the machines will remain on an even keel until they come to a stop1 but the slightest bump or depression1 in connection with a side gust of wind1 may swerve it around and capsize it1 as demonstrated by the illustration of a bad landing by ,de ,lesseps1 ,fig4 #di4 ,this was emphasized by some of the minor accidents at the ,international ,meet near ,new ,york4 ,there is no precision or accuracy in the movements of a flying machine when rolling slowly over the ground after the engine has been shut off1 and the aviator is1 to a certain extent1 helpless4 ,the wheels on most machines are placed too near the center and too close together4 ,when an attempt is made to land with the wind on the quarter or side1 although the machine may strike the ground safely1 owing to the accuracy with which it may be controlled in the air while at speed1 it is apt to turn after rolling a short distance and the wind will then easily capsize it1 breaking a wing1 smashing a propeller1 and sometimes injuring the motor or the aviator4 ,accidents from this cause have been common4 ,these accidents and collisions with obstructions make plain the fact that brakes are quite as necessary on an aeroplane as on any other vehicle intended to run on the ground4 ,practically all aeroplanes are fitted with pneumatic tires and ball-bearing wheels and1 as there is very little head resistance1 they will run a considerable distance after alighting at a speed of #bj to #cj miles an hour4 ,the employment of a brake on the wheels would have averted one of the fatal accidents abroad1 as noted in ,table ,,iii4 ,they would have enabled ,johnstone to stop his machine before colliding with the fence surrounding the aviation grounds at ,denver1 and they would have prevented several minor accidents at various meets1 which1 though not endangering the aviator in every instance1 have often seriously damaged his machine4 ,every exhibition field is obstructed by fences1 posts1 buildings1 and the like1 and to avoid coming in contact with these1 as well as with the irrepressible spectator1 the aviator should certainly have an effective means of bringing the machine to a standstill when it is running along the ground4 ,how much more so is this necessary for cross-country flying when the choice of a landing place is a difficult matter at best4 ,ability to come to a stop quickly would make it possible to land in restricted places where only a very limited run along the ground could be had4 99,lack of ,sufficient ,motor ,control994 ,another class of accidents that take place on the ground suggests the necessity for improving the motor control4 ,in alighting1 the motor is usually stopped by cutting off the ignition--ordinarily by grounding or short-circuiting4 ,throttling to stop appears to be seldom resorted to1 but as several instances have occurred in which the aviator found it impossible to cut off the ignition1 resulting in a collision with another machine or a building1 it is evident that the control should be arranged so that both methods could be employed4 ,with the increasing use of air-cooled motors that may continue to run through self-ignition after the spark has been cut off1 this is more necessary than ever4 ,while it has been demonstrated that the stoppage of the motor does not necessarily involve a fall1 most aviators will naturally prefer to command the assistance of the motor at all times1 and in the case of motors using a carbureter this should be jacketed either from the cooling water or the exhaust1 and means provided for increasing the air supply to prevent the motor stopping at a great height owing to the cold and the rarefied air4 ,the reasons for this have been gone into more at length under the heading of ,altitude4 ,with these and similar improvements that will be suggested by experience and further accidents1 there appears to be no reason why aviation can not be made as safe as the personal equation will permit it to be4 ,there will always be reckless flyers4 ,ignorance and incompetence can not be altogether eliminated any more than they can in sailing1 hunting1 or any other sport4 ,the annual hunting fatalities from these causes in this country alone make a total beside which the aggregate of four years in aviation the world over1 is but an insignificant fraction4 99,parachute ,garment as a ,safeguard994 ,to save as many as possible of these reckless ones from themselves1 so to speak1 a parachute garment has been devised to ease the shock of the fall4 ,it will be recalled that ,voisin would not fly in his biplane until he had provided himself with a heavily-padded helmet1 somewhat on the order of the football headpiece4 ,but neither a padded headpiece nor padded clothing would avail much against a fall of any kind from an aeroplane2 hence1 the parachute garment4 ,its object is not to take the shock of a fall1 as are the pads1 nor is it to prevent a fall1 but to reduce the rate of drop by interposing sufficient air resistance to make the fall safe4 ,this new parachute is in the form of a loose flowing garment1 securely fastened to the body and fitted over a framework carried on the aviator's back4 ,the lower ends of the garment are secured to the ankles4 ,the arrangement is such that when the aviator throws out his arms1 the garment is extended somewhat in umbrella or parachute form1 thus creating sufficient resistance to prevent too rapid a descent4 ,experiments have been made with this parachute dress in which the wearer has jumped from buildings1 cliffs1 and other heights1 and the garment has assumed its role of parachute at once1 permitting a safe and easy descent4 99,study of ,stresses in ,fancy ,flying994 ,to sum up1 it will be seen that the most prolific cause of fatalities is the personal equation4 ,of all the many dangers encountered in aeroplaning1 one of the most clearly defined1 as well as one of the most seductive1 results from fancy flying3 from wheeling round sharp1 horizontal curves2 from conic spiraling2 from cascading1 swooping1 and undulating in vertical plane curves1 popularly dubbed stunts4 ,these are forms of flying in which aviators constantly vie with one another4 ,they frequently result in imposing stresses upon the machine which are far beyond its capacity to withstand4 ,the danger is particularly alluring to reckless young aviators engaged in public exhibitions4 ,the death of ,st4 ,croix ,johnstone1 at the ,chicago ,meet in the summer of #aiaa1 affords a typical illustration of what may be expected as the result of such performances4 ,nevertheless1 partly because they do not adequately appreciate the risk1 and largely1 no doubt1 because of the liberal applause accorded by an admiring throng which also fails to realize the hazardous nature of the fascinating maneuvers1 there will doubtless always be aviators to undertake such feats4 ,singularly enough1 the exact magnitude of such hazards1 or more accurately1 the extent of the increased stress in the machine1 though beyond even the approximate guess of the aviator1 is capable of nice computation in terms of the speed and curvature of flight4 ,during an exhibition meet in ,washington1 ,d4 ,c1 during the summer of #aiaa1 ,glenn ,h4 ,curtiss found difficulty in restraining one of his young pupils from executing various hair-raising maneuvers4 ,he would plunge from a great elevation to acquire the utmost speed1 then suddenly rebound and shoot far aloft4 ,he would undulate about the field1 and on turns would bank the machine until the wings appeared to stand vertical4 ,curtiss solemnly warned the young aviator and earnestly restrained him1 pointing out the dangers of sweeping sharp curves at high speed1 of swooping at such dangerous angles1 and the like4 ,curtiss then turned to ,a4 ,f4 ,zahm and expressed the wish that someone would determine exactly the amount of the added stress in curvilinear flight4 ,the following1 published by ,zahm1 in the ,scientific ,american1 gives the method of calculating this3 ,when a body pursues a curvilinear path in space1 the centripetal force urging it at any instant may be expressed by the equation ,fn m7,v_/,r7 7absolute units7 7m_/g77,v_/,r7 7gravitational units7 in which ,fn is the centripetal force1 m the mass of the body1 ,v its velocity1 and ,r the instantaneous radius of curvature of the path followed by its center of mass4 ,since the mass may be regarded as constant for any short period1 the equation may be expressed by the following simple law3 ,the centripetal force varies directly as the square of the velocity of flight and inversely as the instantaneous radius of the curvature of its path4 ,in applying the above equation to compute the stress in an aeroplane of given mass m1 we may assume a series of values for ,v and ,r1 compute the corresponding values for ,fn1 and tabulate the results for reference4 ,table ,,iv has been obtained in this manner4 ,it may be noted that on substituting in the equation1 ,v is taken as representing miles per hour1 ,r as feet1 and g as #bb miles an hour1 in order to simplify the figuring1 this being #cb4a feet per second4 ,the table shows at a glance the centripetal force acting on an aeroplane to be a fractional part of the gravitational force1 of weight of the machine and its load4 ,for example1 if the aviator is rounding a curve of #cjj feet radius at #fj miles per hour1 the centripetal force is #j4ee of the total weight4 ,at the excessively high speed of #ajj miles per hour and the extremely short radius of #ajj feet1 the centripetal force would be #d4ee times the weight of the moving mass4 ,the pilot would then feel heavier on his seat than he would sitting still with a man of his own weight on either shoulder4 ,for speeds below #fj miles per hour and radii of curvature above #ejj feet1 the centripetal force is less than one third of the weight4 ,the table gives values for speeds of #cj to #ajj miles per hour1 by increments of #aj miles and for radii of curvature of #ajj to #ejj feet1 by increments of #ajj feet1 so that intermediate speeds and radii may readily be calculated4 ,the entire stress on the aeroplane in horizontal flight1 being substantially the resultant of the total weight and the centripetal force1 can readily be figured by compounding them4 ,thus in horizontal wheeling1 the resultant force as shown in the diagram1 ,fig4 #ej1 is approximately ,f 7,fn,w7 ,in swooping1 or undulating in a vertical plane1 the resultant force at the bottom of the curve has its maximum value ,f 7,fn,w7 and at any other part of the vertical path1 it has a more complex though smaller value1 which need not be given in detail4 ,it is obvious that the greatest stress on the machine occurs at the bottom of a swoop1 if the machine be made to rebound on a sharp curve4 ,the total force 7,fn,w7 sustained at this point may be found from the table1 if ,v and ,r be known1 simply by adding #a to the figures given1 then multiplying by the weight of the machine4 ,for example1 if the speed be #ij miles per hour and the radius of curvature #bjj feet1 the total force on the sustaining surface would be #b4hd times the total weight of the machine4 ,in this case1 the stress on all parts of the framing would be #b4hd times its value in level flight1 when only the weight has to be sustained4 ,the pilot would feel nearly three times his usual weight4 ,illustration3 ,fig4 #ej4 ,force ,diagram in ,horizontal ,wheeling ,from the foregoing1 it is apparent that in ordinary banking at moderate speeds on moderate curves1 the additional stress due to centripetal force is usually well below that due to the weight of the machine1 and that in violent flying1 the added stress may considerably exceed that due to the weight of the machine and may accordingly be dangerous1 unless the aeroplane be constructed with a specially high factor of safety4 ,but there is nothing in the results here obtained that seems to make sharp curving and swooping prohibitive4 ,if the framing of the machine be given an extra factor of safety1 at the expense perhaps of endurance and speed1 it may be made practically unbreakable by such maneuvers1 and still afford to the pilot and spectators alike all the pleasures of fantastic flying4 99,methods of ,making ,tests994 ,in order to obtain actual data for the fluctuations of stress in an aeroplane in varied flying1 it is suggested that the stress or strain of some tension or compression member of the machine be recorded when in action2 or simpler still1 perhaps1 that a record of the aeroplane's acceleration be taken and particularly its transverse acceleration4 ,a very simple device to reveal the transverse acceleration of an aeroplane in flight would be a massive index elastically supported4 ,a lath or flat bar stretching lengthwise of the machine1 one end fixed1 the other free to vibrate1 and carrying a pencil along a vertical chronograph drum1 would serve the purpose4 ,this could be protected from the wind by a housing as shown in the sketch1 ,fig4 #ea4 ,illustration3 ,fig4 #ea4 ,method of ,boxing an ,acceleration ,recorder ,an adjustable sliding weight could be set to increase or diminish the amplitude of the tracing1 and an aerial or liquid damper could be added to smooth the tracing4 ,the zero line would be midway between the tracings made on the drum by the stationary instrument when resting alternately in its normal position and upside down2 the distance between this zero line to the actual tracing of the stationary instrument would be proportional to the aeroplane stresses in level1 rectilinear flight2 while in level flight on a curve1 either horizontal or vertical1 the deviation of the mean tracing from the zero line would indicate the actual stress during such accelerated flight4 ,of course1 the drum could be omitted and a simple scale put in its place1 so that the pilot could observe the mean excursion of the pencil or pointer from instant to instant2 also1 the damper of such excursion could be adjusted to any amount in the proposed instrument if the vibrating lath fitted its encasing box closely with an adjustable passage for the air as it moved to and fro2 or if light damping wings were added to the lath1 or flat pencil bar4 ,another method would be to obtain by instantaneous photography the position of the centroid of the aeroplane at a number of successive instants1 from which could be determined its speed and path1 or ,v and ,r of the first equation1 by which data1 therefore1 the stress could be read from ,table ,,iv4 ,perhaps the simplest plan would be to add an acceleration penholder1 with its spring and damper1 to any recording drum the aeroplane may carry for recording air pressure1 temperature1 speed1 and so forth4 ,indeed1 all such records could be taken on a single drum4 ,a score of devices1 more or less simple1 but suitable for revealing the varying stress in an aeroplane1 will occur to any engineer who may give the subject attention4 ,and it is desirable in the interests both of aeroplane design and of prudent manipulation that someone obtain roughly accurate data for the stresses developed in actual flight4 99,increment of ,speed in ,driving994 ,it is commonly supposed by aviators that the increment of speed due to driving is very prodigious4 ,an easy formula will determine the major limit of such speed increment4 ,if the initial and natural speed of the aeroplane be v1 and the change of level in diving be h1 while the speed at the end of the dive be ,v1 the minimum change of level necessary to acquire any increment of speed1 ,v--v1 may be found from the equation h 7,v - v7_/#b;g ,if1 as before1 g be taken as #bb miles per hour1 the equation reduces to the convenient formula h 7,v-v7_/#cj in which ,v and v are taken in miles per hour4 ,assuming various values for ,v and v1 ,table ,v has been found for the corresponding values of h in feet3 ,for example1 if the natural speed of the aeroplane in level flight be #ej miles per hour1 and the aviator wishes to increase the speed by #bj miles per hour1 he must dive at least #hj feet1 assuming that the aeroplane falls freely1 like a body in vacuo1 or that its propeller overcomes the air resistance completely2 otherwise the fall must be rather more than #hj feet4 ,it has been suggested that a contest be arranged to determine which aviator could dive most swiftly and rebound most suddenly1 the prize going to the one who should stress his machine most as indicated by the accelerograph above proposed4 ,but to avoid danger1 the contest would have to be supervised by competent experimentalists1 and would be best conducted over water4 ,it is safe to say that more than one well-known aeroplane would be denied entry in such a contest because of lack of a sufficient factor of safety in its construction4 99,dirigible ,accidents994 ,because its wrecks are spectacular and the loss involved tremendous1 the dirigible has probably earned an undeserved reputation1 though it must be admitted that the big airships have come to grief with surprising regularity4 ,the fact must be noted1 however1 that when an airplane is wrecked1 the aviator seldom escapes with his life1 while the spectators' lives are endangered to an even greater extent1 whereas in the case of the dirigible1 the loss is simply financial1 both the crew and passengers usually escaping without a scratch4 ,this is largely due to the fact that the majority of accidents to dirigibles have happened on the ground1 and have been caused by lack of facilities for properly handling or docking the huge gas bag4 ,of course1 lack of flotation or an accident to the motors1 or both combined1 have brought two of the numerous ,zeppelins to earth in a very hazardous manner1 though no one was killed1 while four ,french army officers lost their lives in the ,republique disaster1 the exact cause of which was never definitely ascertained4 ,this was likewise the case with ,erbsloeh and his companion who were dropped from the sky1 their airship having taken fire4 ,it was thought that ignition was caused by atmospheric electricity1 in this instance4 ,by far the great majority of later dirigible accidents have been due solely to the crude methods of handling the airships on the ground1 and the frequency with which these have occurred should certainly have been responsible for the adoption of improvements in this respect at an earlier day4 ,for instance1 the ,morning ,post1 a big ,lebaudy type bought for ,english use1 had the envelope ripped open by an iron girder projecting from its shed4 ,repairs took several months1 and at the end of the first trial thereafter1 the ship was again ,wrecked in landing4 ,a company of soldiers failed to hold the big craft and it drifted broadside into a clump of trees1 hopelessly wrecking it4 ,in attempting to dock the ,deutschland ,i1 #bjj men were unable to hold it down1 a heavy gust of wand catching the big airship and pounding it down on top of a wind break that had been specially erected at the entrance of the shed for protection4 ,a similar accident happened to the big ,parseval1 a violent gust of wind casting it against the shed and tearing such a hole in the envelope that the gas rushed out and the car dropped #cj feet to the ground4 ,the big ,british naval dirigible of the rigid type1 the ,mayfly1 was broken in half in attempting to take it out of the shed the first time4 ,a cross wind was blowing and the gas bag of one of the central sections was torn1 deflating it and showing in a striking manner that the solidity of a rigid dirigible results chiefly from the aerostatic pressure of the gas in its various compartments4 ,without the gas lift1 a rigid frame is so in reality only for certain limited distances1 as was shown by the total collapse of the ,mayfly's frame after having been subjected to the opposed leverage of the parts on either side of the original break4 ,this1 of course1 was an error in design1 as the frame of a rigid dirigible should certainly not be so weak in itself as to collapse upon the deflation of a single one of the central compartments4 ,the incident on the trip of the ,zeppelin ,,iii to ,berlin1 in #aiji1 when the flying blades of a broken propeller pierced the hull without causing an accident1 shows how much resistance it may offer4 ,this is exactly what occured at the ,chicago ,meet1 ,august #ae1 #aiaa1 when ,badger's ,baldwin biplane collapsed at the end of a long dive1 causing the death of the aviator4 ,,amateur ,,aviators ,it will probably come as a surprise to the average reader to learn that at the end of #aiaj1 there were more than a thousand amateur aviators in this country1 though all the flights which form the subject of newspaper reports have been the work of not more than a dozen flyers and doubtless half the population has not as yet seen an aeroplane in flight4 ,the desire to fly1 whether it be to satisfy one's desire to soar above the world in seeming defiance of natural laws1 or merely to obtain the financial reward that is won by successful flight1 attracts a great many from all stations and walks of life4 ,this is particularly true among older boys who look on aviation as an advanced form of kite-flying4 ,an example of rather serious work along this line may be cited of two high school boys of ,chicago1 ,harold ,turner and ,fred ,croll1 who built a monoplane weighing #abe pounds1 ,fig4 #eb4 ,this machine1 although too small for a motor1 was equipped with rudder and other operating planes and levers1 the elevating plane and ailerons being automatically operated by an electrical device4 ,on one of its flights the machine1 carrying a #abj pound operator1 was started and propelled by attaching it to an automobile2 it rose to a height of #ae feet1 and remained in the air #dc seconds4 ,contrary to all precedent1 the average amateur is bent upon achieving what the skilled professional considers as beyond even his talent and resources--that of building his own flying machine4 ,with every other mechanical vehicle1 the amateur learns to drive first and the majority are content with that achievement--for example1 very few chauffeurs have any great ambition to build their own automobiles4 ,with flying machines 7one of the most difficult of mechanical contrivances71 nearly all amateurs want to construct new types for themselves and all confidently expect to fly with no more knowledge than that gained in constructing them4 ,we all have to be apprentices before becoming masters1 so all aviators necessarily have to be learners and grass cutters before being professionals4 ,charles ,k4 ,hamilton was an exception1 but he was already an expert pilot of dirigible balloons1 and he did not try to build his own aeroplane4 ,willard1 ,mars1 and ,ely1 all ,curtiss pupils1 flew after a very short training1 but they did not attempt to construct aeroplanes for themselves4 ,this is also true of ,clifford ,b4 ,harmon1 the champion amateur4 ,illustration3 ,fig4 #eb4 ,what an ,amateur ,aviator ,can ,do in ,building an ,aeroplane 99,classes of ,amateurs994 ,inventors4 ,generally speaking1 amateurs are of two classes4 ,those of the first class believe they have conceived some entirely new system or invention1 or an improvement on some machine that has previously proved a failure2 they think they have discovered the secret which other inventors who preceded them failed to grasp4 ,they expend their meager capital in trying to realize high hopes4 ,a comparatively small number ever get as far as completing the machine and one trial on the field is usually sufficient to put a quietus on those who do1 as it is disappointing1 to say the least1 to see the result of a number of months' work undone in a twinkling without the machine having shown the least disposition or ability to get off terra firma4 ,would ,be ,performers4 ,the second class finds its chief incentive in the munificent reward to be gained with what appears to be comparatively little effort or expenditure1 and the amateur who is seeking financial returns has no alternative except to build his own machine1 or enter either the ,wright or ,curtiss school of flying and secure a berth with one of these companies4 99,wright and ,curtiss ,patents994 ,this is the result of conditions at present obtaining in the field of aviation4 ,the only generally successful types of ,american aeroplanes are the ,wright and ,curtiss1 and the acquirement of a biplane of either type means the expenditure of at least #e1jjj for the machine alone1 and they are sold only to individuals on the express condition that the machines are not to be used for exhibition or as a means of profit to the owner4 ,the manufacturers have expert flyers of their own who attend meets and fairs throughout the country4 ,it would make their monopoly impossible to allow outsiders to fly their aeroplanes publicly or to exhibit them4 ,by this restriction the price of the machines is kept up and large returns are gained by exhibitions and flying4 ,to break this monopoly by importing ,european machines is not possible4 ,all the successful aeroplanes made abroad such as the ,farman1 ,cody1 and ,sommer biplanes2 and the ,bleriot1 ,antoinette1 and ,grade monoplanes are fitted with devices of control or stability1 or both1 covered by the ,wright patents and can not be flown in this country without legal trouble4 ,the numerous foreign aviators who brought over their machines in the fall of #aiaj to compete at the ,international ,meet1 did so only on being granted a concession by the ,wright ,company to the effect that they would not be considered as infringers and sued4 ,similar arrangements were made at subsequent meets and this handicap will always be present where foreign machines are used4 ,evasion by ,invention of ,new ,types4 ,but when he thinks of the unprecedented sums paid professionals for simply exhibiting their machines and making short flights1 the amateur is anxious to obtain a share of the profits4 ,no thought is given the fact that were he and all his kind permitted to fly1 the achievement would soon be commonplace and the aviator's golden age would be over4 ,there are accordingly hundreds of would-be aviators in this country today who are striving to evade the ,wright basic patents by either devising entirely new types of aeroplanes1 or by inventing new methods of control and stability that will not infringe4 ,others1 reasoning that the old aeroplanes built before the advent of the ,wright machine cannot be held as infringements owing to priority1 propose to develop ,maxim1 ,langley1 and ,ader machines1 though the dictum in the ,new ,york ,court of ,appeals decision referred to under the head of ,legal ,status of ,wright ,patent1 which states that a prior machine which had never been known to fly would not be considered an anticipation of a modern successful machine1 may prove a stumbling block in their case as well4 ,thus1 a round of the workshops of these enthusiasts reveals a host of heavier-than-air machines of every conceivable type and shape1 every one of which1 according to its builder1 is an aeroplane that will fly4 ,mineola and ,garden ,city1 ,long ,island1 harbor a score of these little shops the year round1 but the same scenes are being enacted on a smaller scale in almost every state in the ,union1 and particularly in ,california1 ,ohio1 ,kansas1 ,massachusetts1 and ,arizona1 in addition to which there are many who are carrying their experiments on in secret4 ,each believes deep in his heart that he will succeed where a master failed4 ,maxim failed with this type of machine1 quotes one4 ,how did he expect to fly when his control was not proportionate to the machine's lift capacity8 ,seemingly1 nobody ever thought of that and our friend will make a fortune by going ,maxim one better1 but he does not4 ,after months of labor and a great deal of expense he finds that some unforeseen difficulty develops which keeps his machine to earth as if it were part and parcel of it4 ,another has conceived a type of monoplane that is entirely new--different from any existing type--and as the latter are all foreign1 he prides himself on having developed a monoplane that will be entirely ,american--the first and only ,american monoplane4 ,theoretically1 it is a wonder2 mechanically it is correct2 and it speeds over the turf with surprising velocity2 but when the elevating rudder is operated to make the machine rise1 it balks and plunges head first into the ground4 ,again and again1 the propeller and other broken parts are replaced at no small expense2 again and again the inventor goes over every part of the machinery and computes the dimensions of the supporting surface to see if it all corresponds with the formula of his special theory4 ,but time after time1 the aeroplane acts like a jumping frog and lands head first4 ,at last1 its builder becomes convinced that there is something radically wrong and begins to depart from his original plans1 involving changes that simply mean a waste of effort and money1 since the inventor does not himself know what he is trying to correct and no one else knows better than he what the trouble is4 ,evasion by ,acquiring ,european ,types4 ,others still1 realizing from the foregoing experiences that it is almost impossible to construct an entirely new type of aeroplane off-hand1 acquire ,european types and propose to fit them with new control and stability devices1 such as are not covered by the ,wright patents4 ,so far1 none has succeeded4 ,somehow1 the ,wrights seem to have covered all the conceivable working devices for control and stability1 and the numerous attempts have accordingly resulted in failure4 ,undoubtedly1 some of these aeroplanes built by amateurs may really be capable of flight2 but how is the inventor to know it when he lacks the ability to operate it8 ,to know how to fly an aeroplane is a condition precedent to success in the field of aviation that can not be met by building of a machine4 ,the beginner is thus badly handicapped4 ,even though his machine may embody the elements essential to successful flight1 he may never be able to establish the fact1 since his first blundering attempt or two frequently ends by wrecking the machine1 and many have neither the means nor the stamina to persevere further after a few bad wrecks1 involving weeks and weeks of rebuilding each time4 ,he can not engage an expert to fly his machine for him1 as the expert's time per minute figures out a price that makes him gasp1 and even at that the expert professional's time is pretty much all taken4 ,furthermore1 very few would run the risk of attempting to fly an untried aeroplane--they have more to lose through accidental injury than the builder has through the failure of his theories4 ,and so it is with most inventors4 ,they may have conceived something really good1 but it is not complete1 and an aeroplane is hardly worth its weight as junk unless it is4 ,hundreds of patents are taken out every year on devices to be used on heavier-than-air machines2 inventors by scores make daily rounds trying to interest financiers in some seemingly wonderful mechanical scheme1 and dozens of companies are organized each year to exploit some especially promising inventions4 ,numbers of aeroplanes are constructed and hailed as marvels1 but1 somehow1 when a successful flight is made by an amateur it is always with some standard aeroplane1 either of the ,curtiss or ,farman types1 and mostly the former4 ,in fact1 the ,curtiss has become a favorite with the amateur since the ,federal court refused to sustain the granting of a preliminary injunction in favor of the ,wright ,company against ,glenn ,h4 ,curtiss4 ,it is accordingly being taken for granted in general that the outcome of the ,wright vs4 ,curtiss litigation will be to declare the ,curtiss machine non-infringing4 ,should it be the other way about1 there will certainly be gloom and despair in the amateur camps throughout the country4 ,however1 neither the ,wrights nor ,curtiss impose any restriction upon the building of machines of their types for experimental purposes1 so that the amateur who wishes to copy them may safely do so1 provided no attempt be made to employ the machine for purposes of public exhibition or financial gain4 ,,examination ,,paper ,,building ,,and ,,flying ,,an ,,aeroplane 99,,part ,,ii99 99,read ,carefully993 ,place your name and full address at the head of the paper4 ,any cheap1 light paper like the sample previously sent you may be used4 ,do not crowd your work1 but arrange it neatly and legibly4 ,do not copy the answers from the ,instruction ,paper2 use your own words so that we may be sure that you understand the subject4 #a4 ,contrast the ,bleriot with the ,curtiss in every essential particular4 #b4 ,give details of the ,bleriot running gear4 #c4 ,how is the supporting plane of the ,bleriot built and reinforced8 #d4 ,what sort of fabric is used to cover the plane and how is it fastened on8 #e4 ,describe by sketch the ,bleriot control system4 #f4 ,how does the location of the motor in the ,bleriot compare with its location in the ,curtiss8 #g4 ,what is 8grass-cutting0 and why is it practiced8 #h4 ,describe some of the devices used in aviation schools4 #i4 ,how is the elevating plane manipulated to start the aeroplane from the ground8 #aj4 ,how is the static balance of a machine determined8 #aa4 ,how does warping the wings affect the behavior of an aeroplane8 ,how should this be practiced8 #ab4 ,give the process of making a turn in an aeroplane4 #ac4 ,what is 8banking08 ,what must be done to prevent excessive banking on a turn8 #ad4 ,how can a turn be made in a wind8 #ae4 ,why should the start and the landing always be made in the teeth of the wind8 #af4 ,what is the attitude of the masters of aviation toward fancy flying8 #ag4 ,classify the most common sources of accidents4 #ah4 ,what must an aviator do in case his motor stops in midair8 ,is this considered a dangerous situation8 #ai4 ,what are the relative merits of biplane and monoplane as regards the avoidance of accidents8 #bj4 ,what are some of the devices used to protect the aviator in case his machine collapses8 #ba4 ,analyze rather carefully the additional stresses put upon an aeroplane when an aviator suddenly swoops and then rights his machine by a quick movement of the control4 99,after completing the work1 add and sign the following statement399 ,i hereby certify that the above work is entirely my own4 7,signed7