Front view of the Santos-Dumont monoplane, showing position of tubular struts supporting the engine and the wings; also the guys, and warping wires entering the tubes inside the wheels. MP, the main plane; TP, tail plane in the rear; R, radiators; M, motor; P, propeller, the arrow showing direction of revolution.
The front spar is set about 9 inches back from the front edge of the plane, and the rear one about 12 inches forward of the back edge of the plane. Across these spars, and beneath them, running fore and aft, are bamboo rods about ¾ of an inch in diameter at the forward end, and tapering toward the rear. They are set 8½ inches apart (centre to centre), except at the tips of the wings. The two outer panels are 10¼ inches from centre to centre of the rods, to give greater elasticity in warping. These fore-and-aft rods are 6 feet 5 inches long, except directly back of the propeller, where they are 5 feet 8 inches long; they are bound to the spars with brass wire No. 25, at the intersections. They also are bent to a curved form, as shown in the plans, by the aid of the hot-water bath. Diagonal guys of piano wire are used to truss the frame in two panels in each wing.
Around the outer free ends of the rods runs a piano wire No. 20, which is let into the tips of the rods in a slot ⅜ inch deep. To prevent the splitting of the bamboo, a turn or two of the brass wire may be made around the rod just back of the slot; but it is much better to provide thin brass caps for the ends of the rods, and to cut the slots in the metal as well as in the rods. Instead of caps, ferrules will do. When the slots are cut, let the tongue formed in the cutting be bent down across the bamboo to form the floor to the slot, upon which the piano wire may rest. The difference in weight and cost is very little, and the damage that may result from a split rod may be serious.
Plan and details of construction of La Demoiselle.
After the frame of the plane is completed it is to be covered with cloth on both sides, so as entirely to enclose the frame, except only the tips of the rods, as shown in the plans. In the Santos-Dumont monoplane the cloth used is of closely woven silk, but a strong, unbleached muslin will do—the kind made especially for aeroplanes is best.
Both upper and lower surfaces must be stretched taut, the edges front and back being turned over the piano wire, and the wire hemmed in. The upper and lower surfaces are then sewed together—“through and through,” as a seamstress would say—along both sides of each rod, so that the rods are practically in “pockets.” Nothing must be slighted, if safety in flying is to be assured.
Sectional diagram of 2-cylinder Darracq opposed motor.
