The first vertical struts on each side are extras, without corresponding horizontal ones; they serve only to support the engine. When the Gnome motor is used, its central shaft is carried at the centers of two X-shaped, pressed-steel frames, one on the front side, flush with the end of the fuselage and one on the rear.
Truss Frame Built on Fuselage. In connection with the fuselage may be considered the overhead truss frame and the warping frame. The former consists of two inverted V's of 20-gauge, 1- by 3/8-inch oval tubing, joined at their apexes by a 20-gauge, 3/4-inch tube. Each V is formed of a single piece of the oval tubing about 5 feet long. The flattened ends of the horizontal tube are fastened by a bolt in the angles of the V's. The center of the horizontal tube should be 2 feet above the top of the fuselage. The flattened lower ends of the rear V should be riveted and brazed to strips of 18-gauge steel, which will fit over the bolts attaching the vertical fuselage struts at this point. The legs of the front V should be slightly shorter, as they rest on top of the wing socket tube. Each should be held down by a single 3/16-inch bolt, passing through the upper wall of the tube and its retaining strap; these bolts also serve the purpose of preventing the tube from sliding out from under the strap. Each side of the frame is now braced by diagonal wires (No. 20 piano wire, or 1/14-inch cable) with turnbuckles.
At the upper corners of this frame are attached the wires which truss the upper sides of the wings. The front wires are simply fastened under the head and nut of the bolt which holds the frame together at this corner. The attachment of the rear wires, however, is more complex, as these wires must run over pulleys to allow for the rocking of the rear wing beams when the wings are warped. To provide a suitable place for the pulleys, the angle of the rear V is enclosed by two plates of 20-gauge sheet steel, one on the front and one on the rear, forming a triangular box 1 inch thick fore and aft, and about 2 inches on each side, only the bottom side being open. These plates are clamped together by a 3/16-inch steel bolt, on which are mounted the pulleys. There should be sufficient clearance for pulleys 1 inch in diameter. The wires running over these pulleys must then pass through holes drilled in the tube. The holes should not be drilled until the wings are on, when the proper angle for them can be seen. The cutting and bending of the steel plates is a matter of some difficulty, and should not be done until the frame is otherwise assembled, so that paper patterns can be cut for them. They should have flanges bent around the tube, secured by the bolts which hold the frame together, to keep them from slipping off.
The oval tubing is used in the vertical parts of this frame, principally to reduce the wind resistance, being placed with the narrow side to the front. However, if this tubing be difficult to obtain, or if price is a consideration, no harm will be done by using 3/4-inch round tubing. Beneath the floor of the driver's cockpit in the fuselage is the warping frame, the support for the wires which truss the rear wing beams and also control the warping.
This frame is built up of four 3/4-inch, 20-gauge steel tubes, each about 3 feet long, forming an inverted, 4-sided pyramid. The front and back pairs of tubes are fastened to the lower fuselage beams with 3/16-inch bolts at points 15 inches front and back of the horizontal strut. 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 turned. In the genuine Bleriot, this fixture is a special casting. However, a very neat connection can be made with a piece of 1/16-inch steel stock, 1 1/4 by 6 inches, bent into a U-shape with the legs 1 inch apart inside. The flattened ends of the tubes are riveted and brazed to the outside upper corners of the U, and a bolt to carry the pulleys passes through the lower part, high enough to give clearance for 2-inch pulleys. This frame needs no diagonal wires.
Running Gear. Passing now to the running gear, the builder will encounter the most difficult part of the entire machine, and it is impossible to avoid the use of a few special castings. The general plan of the running gear is shown in the drawing of the complete machine. Figs. 23 and 24, while some of the details are illustrated in Fig. 27, and the remainder are given in the detail sheet, Fig. 28. It will be seen that each of the two wheels is carried in a double fork, the lower fork acting simply as a radius rod, while the upper fork is attached to a slide which is free to move up and down on a 2-inch steel tube. This slide is held down by two tension springs, consisting of either rubber tubes or steel coil springs, which absorb the shocks of landing. The whole construction is such that the wheels are free to pivot sideways around the tubes, so that when landing in a quartering wind the wheels automatically adjust themselves to the direction of the machine.
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
Framework. The main framework of the running gear consists of two horizontal beams, two vertical struts, and two vertical tubes. The beams are of ash, 4 3/4 inches wide in the middle half, tapering to 3 3/4 inches at the ends, and 5 feet 2 3/4 inches long overall. The upper beam is H inch thick and the lower 1 inch. The edges of the beams are rounded off except at the points where they are drilled for bolt holes for the attachment of other parts. The two upper beams of the fuselage rest on these beams and are secured to them by two 3/16-inch bolts each.
The vertical struts are also of ash, 1 3/16 inch by 3 inches and 4 feet 2 inches long overall. They have tenons at each end which fit into corresponding square holes in the horizontal beams. The two lower fuselage beams are fastened to these struts by two 3/16-inch through bolts and steel angle plates formed from 1/16-inch sheet steel. The channel section member across the front sides of these struts is for the attachment of the motor, and will be taken up later. The general arrangement at this point depends largely on what motor is to be used, and the struts should not be rounded or drilled for bolt holes until this has been decided.