Fig. 48. Voisin biplane
"The biplane, or two plane machine, is fitted up on somewhat the same lines as the monoplane, having two planes one above the other, as I show you in [Fig. 47]. The dark portion A A, shows the positions and curvature of the planes. The plane B is called the elevator because it keeps up the head of the machine. C shows the tail with a single plane. D is the part containing the mechanism and the aviator's seat. E shows the vertical planes, made of some light fabric stretched over a bamboo frame. The propeller is shown at F, and it is about six feet in diameter. The two carrying wheels, shown at G G, are simply light bicycle wheels which tend to ease the landing of the machine when it comes to the earth. It will be seen that machines may differ in the style of construction and yet, so long as they contain the principles I have described, they will fly with more or less success. The illustration, ([Fig. 48]), shows the plan of the biplane, which is somewhat different in arrangement from the monoplane. This sketch is of the Voisin biplane and shows the tail-piece, something not used in machines of the Wright type. The Voisin machine is quite popular in Europe, particularly in France. It is not very difficult to construct or easy to control; at least, it has that reputation.
Fig. 49. The Santos-Dumont monoplane
"The Santos Dumont monoplane, Demoiselle, shown in [Fig. 49], is said to be the smallest and lightest known practical machine, and there are no patents on it, the inventor having published sketches and drawings of all its details. Contrary to the usual plan, the aviator, in this machine, sits below the motor, so that the propeller blades cut across the line of sight; but as it revolves very rapidly the vision is not affected. The whole machine, when complete, weighs only about 250 pounds. Its length is about 20 feet and its total width over the planes 18 feet, and it is about 7 feet 6 inches high. It is quite easy to build, as the framework, or chassis, is fixed to a bent piece of ash or elm—like a sleigh runner—which answers very well, because when the machine begins to move the rear end rises first. If desired, the frame can be made so that the whole thing can be taken apart. Sockets, like those used on finishing rods, may be attached at the joints and junctions to hold the structure together. The two spars that constitute the main support of the planes are formed of ash, this having been found the best material for the purpose, as it is also for the making of the propeller blades. One of the spars should be fixed about nine inches from the front edge, and the other about twelve inches from the back. Bamboo cross pieces are fastened about nine or ten inches apart between the two main spars. All is covered with oiled silk, applied in two thicknesses. The area of the main plane is some 115 square feet, and that of the tail-piece about 50 square feet. To cover all this would require about 400 square feet of silk.
"I have heard it said that aeroplanes are hard to manage, difficult to drive, and extremely dangerous. This is not true entirely, but there is some truth in it. An amateur has to go through a 'course of sprouts' and must learn all about his machine before beginning to use it practically. Once he becomes master of it and can keep it well under control, he need not fear accidents, if he does not lose his head, nor venture out in half a gale. When we consider the number of experiments that have been made from time to time with imperfect machines, we find that fatal accidents have been very few, less, indeed, than the number recorded in the early stages of automobile history.
"I have been compelled to draw a number of the points I have given you from many sources, particularly from the writings of Messrs. Fetherstonhaugh and Lanchester, which does not detract from what I have told you, but rather guarantees its correctness.
"Well, children—it is getting late, but, before bidding you good-night, I think I should finish my talk on aeroplanes by showing you how to make a small model of a flying machine, if you are not too tired to listen further?"