INDEX OF ILLUSTRATIONS.
| FIG. | PAGE | |
| [1]. | Diagram showing the reduction of the projected horizontal area, | 2 |
| [2]. | Professor Langley’s experiments, | 5 |
| [3]. | Eagles balancing themselves on an ascending current of air, | 14 |
| [4]. | Air currents observed in Mid-Atlantic, | 16 |
| [5]. | Glassy streaks in the Bay of Antibes, | 17 |
| [6]. | Air currents observed in the Mediterranean, | 18 |
| [7]. | The circulation of air produced by a difference in temperature, | 27 |
| [8]. | Kite flying, | 29 |
| [9]. | Group of screws and other objects used in my experiments, | 32 |
| [10]. | Some of the principal screws experimented with, | 32 |
| [11]. | The three best screws, | 33 |
| [12]. | Apparatus for testing the thrust of screws, | 34 |
| [13]. | Apparatus for testing the direction of air currents, | 35 |
| [14]. | The ends of screw blades, | 36 |
| [15]. | The manner of building up the large screws, | 39 |
| [16]. | A fabric-covered screw, | 40 |
| [17]. | The hub and one of the blades of the screw on the Farman machine, | 42 |
| [18]. | Section of screw blades having radial edges, | 43 |
| [19]. | Form of the blade of a screw made of sheet metal, | 44 |
| [20]. | New form of hub, | 45 |
| [21]. | Small apparatus for testing fabrics for aeroplanes, | 50 |
| [22]. | Apparatus for testing the lifting effect of aeroplanes and condensers, | 51 |
| [23]. | Apparatus for testing aeroplanes, condensers, &c., | 52 |
| [24]. | Cross-sections of bars of wood, | 53 |
| [25]. | Sections of bars of wood, | 54 |
| [26]. | A flat aeroplane placed at different angles, | 55 |
| [27]. | Group of aeroplanes used in experimental research, | 56 |
| [28]. | An 8-inch aeroplane which did very well, | 57 |
| [29]. | Resistance due to placing objects in close proximity to each other, | 58 |
| [30]. | Cross-section of condenser tube made in the form of Philipps’ sustainers, | 60 |
| [31]. | The grouping of condenser tubes made in the form of Philipps’ sustainers, | 61 |
| [32]. | Machine with a rotating arm, | 63 |
| [33]. | A screw and fabric-covered aeroplane in position for testing, | 64 |
| [34]. | The rotating arm of the machine with a screw and aeroplane attached, | 65 |
| [35]. | The little steam engine used by me in my rotating arm experiments, | 66 |
| [36]. | The machine attached to the end of the rotating shaft, | 68 |
| [37]. | Marking off the dynamometer, | 69 |
| [37a]. | Right- and left-hand four-blade screws, | 70 |
| [38]. | Apparatus for indicating the force and velocity of the wind direct, | 71 |
| [39]. | Apparatus for testing the lifting effect of aeroplanes, | 73 |
| [40]. | Front elevation of proposed aeroplane machine, | 77 |
| [41]. | Side elevation of proposed aeroplane machine, | 78 |
| [42]. | Plan of proposed aeroplane machine, | 79 |
| [43]. | Plan of a hélicoptère machine, | 82 |
| [44]. | Showing the position of the blades of a hélicoptère as they pass around a circle, | 83 |
| [45]. | System of splicing and building up wooden members, | 86 |
| [46]. | Cross-section of struts, | 86 |
| [47]. | Truss suitable for use with flying machines, | 87 |
| [48]. | The paradox aeroplane, | 88 |
| [49]. | The Antoinette motor, | 89 |
| [50]. | Section showing the Antoinette motor as used in the Farman and De la Grange machines, | 90 |
| [51]. | Pneumatic buffer, | 91 |
| [52]. | Gyroscope, | 94 |
| [53]. | Adjusting the lifting effect, | 95 |
| [54]. | Showing that the machine could be tilted in either direction by changing the position of the rudder, | 96 |
| [55]. | Adjusting the lifting effect, | 97 |
| [56]. | Adjustment of the rudders, | 98 |
| [57]. | Diagram showing the evolution of a wide aeroplane, | 102 |
| [58]. | In a recently published mathematical treatise on aerodynamics an illustration is shown, representing the path that the air takes on encountering a rapidly moving curved aeroplane, | 104 |
| [59]. | An illustration from another scientific publication also on the dynamics of flight, | 104 |
| [60]. | Another illustration from the same work, | 105 |
| [61]. | The shape and the practical angle of an aeroplane, | 105 |
| [62]. | An aeroplane of great thickness, | 106 |
| [63]. | Section of a screw blade having a rib on the back, | 106 |
| [64]. | Shows a flat aeroplane placed at an angle of 45°, | 107 |
| [65]. | The aeroplane here shown is a mathematical paradox, | 107 |
| [66]. | This shows fig. 65 with a section removed, | 107 |
| [67]. | Diagram showing real path of a bird, | 108 |
| [68]. | The De la Grange machine on the ground, | 111 |
| [69]. | The De la Grange machine in full flight, | 111 |
| [70]. | Farman’s machine in flight, | 112 |
| [71]. | Bleriot’s machine, | 113 |
| [72]. | Santos Dumont’s flying machine, | 113 |
| [72a]. | Angles and degrees compared, | 115 |
| [72b]. | Diagram showing direction of the air with a thick curved aeroplane, | 118 |
| [72c]. | Aeroplanes experimented with by Mr. Horatio Philipps, | 118 |
| [73]. | The enormous balloon “Ville de Paris,” | 123 |
| [74]. | Photograph of a model of my machine, | 130 |
| [75]. | The fabric-covered aeroplane experimented with, | 131 |
| [76]. | The forward rudder of my large machine showing the fabric attached to the lower side, | 131 |
| [77]. | View of the track used in my experiments, | 134 |
| [78]. | The machine on the track tied up to the dynamometer, | 135 |
| [79]. | Two dynagraphs, | 136 |
| [80]. | The outrigger wheel that gave out and caused an accident with the machine, | 137 |
| [81]. | Shows the broken planks and the wreck that they caused, | 138 |
| [82]. | The condition of the machine after the accident, | 139 |
| [83]. | This shows the screws damaged by the broken planks, | 140 |
| [84]. | This shows a form of outrigger wheels which were ultimately used, | 141 |
| [85]. | One pair of my compound engines, | 142 |
| [86]. | Diagram showing the path that the air has to take in passing between superposed aeroplanes in close proximity to each other, | 144 |
| [87]. | Position of narrow aeroplanes arranged so that the air has free passage between them, | 145 |
| [88]. | The very narrow aeroplanes or sustainers employed by Mr. Philipps, | 146 |
| [89]. | One of the large screws being hoisted into position, | 149 |
| [90]. | Steam boiler employed in my experiments, | 157 |
| [91]. | The burner employed in my steam experiments, | 157 |
| [92]. | Count Zeppelin’s aluminium-covered airship coming out of its shed on Lake Constance, | 161 |
| [93]. | Count Zeppelin’s airship in full flight, | 161 |
| [94]. | The new British war balloon “Dirigible” No. 2, | 162 |
| [95]. | The Wright aeroplane in full flight, | 162 |
ARTIFICIAL AND NATURAL FLIGHT.
CHAPTER I.
INTRODUCTORY.
It has been my aim in preparing this little work for publication to give a description of my own experimental work, and explain the machinery and methods that have enabled me to arrive at certain conclusions regarding the problem of flight. The results of my experiments did not agree with the accepted mathematical formulæ of that time. I do not wish this little work to be considered as a mathematical text-book; I leave that part of the problem to others, confining myself altogether to data obtained by my own actual experiments and observations. During the last few years, a considerable number of text-books have been published. These have for the most part been prepared by professional mathematicians, who have led themselves to believe that all problems connected with mundane life are susceptible of solution by the use of mathematical formulæ, providing, of course, that the number of characters employed are numerous enough. When the Arabic alphabet used in the English language is not sufficient, they exhaust the Greek also, and it even appears that both of these have to be supplemented sometimes by the use of Chinese characters. As this latter supply is unlimited, it is evidently a move in the right direction. Quite true, many of the factors in the problems with which they have to deal are completely unknown and unknowable; still they do not hesitate to work out a complete solution without the aid of any experimental data at all. If the result of their calculations should not agree with facts, “bad luck to the facts.” Up to twenty years ago, Newton’s erroneous law as relates to atmospheric resistance was implicitly relied upon, and it was not the mathematician who detected its error, in fact, we have plenty of mathematicians to-day who can prove by formulæ that Newton’s law is absolutely correct and unassailable. It was an experimenter that detected the fault in Newton’s law. In one of the little mathematical treatises that I have before me, I find drawings of aeroplanes set at a high and impracticable angle with dotted lines showing the manner in which the writer thinks the air is deflected on coming in contact with them. The dotted lines show that the air which strikes the lower or front side of the aeroplane, instead of following the surface and being discharged at the lower or trailing edge, takes a totally different and opposite path, moving forward and over the top or forward edge, producing a large eddy of confused currents at the rear and top side of the aeroplane. It is very evident that the air never takes the erratic path shown in these drawings; moreover, the angle of the aeroplane is much greater than one would ever think of employing on an actual flying machine. Fully two pages of closely written mathematical formulæ follow, all based on this mistaken hypothesis. It is only too evident that mathematics of this kind can be of little use to the serious experimenter. The mathematical equation relating to the lift and drift of a well-made aeroplane is extremely simple; at any practicable angle from 1 in 20 to 1 in 5, the lifting effect will be just as much greater than the drift, as the width of the plane is greater than the elevation of the front edge above the horizontal—that is, if we set an aeroplane at an angle of 1 in 10, and employ 1 lb. pressure for pushing this aeroplane forward, the aeroplane will lift 10 lbs. If we change the angle to 1 in 16, the lift will be 16 times as great as the drift. It is quite true that as the front edge of the aeroplane is raised, its projected horizontal area is reduced—that is, if we consider the width of the aeroplane as a radius, the elevation of the front edge will reduce its projected horizontal area just in the proportion that the versed sine is increased. For instance, suppose the sine of the angle to be one-sixth of the radius, giving, of course, to the aeroplane an inclination of 1 in 6, which is the sharpest practical angle, this only reduces the projected area about 2 per cent., while the lower and more practical angles are reduced considerably less than 1 per cent. It will, therefore, be seen that this factor is so small that it may not be considered at all in practical flight.