Building and Flying an Aeroplane / A practical handbook covering the design, construction, and operation of aeroplanes and gliders

by Charles B. Hayward

Fuselage. Like most monoplanes, the Bleriot has a long central body, usually termed "fuselage," to which the wings, running gear, and controls are all attached. A drawing of the fuselage with all dimensions is reproduced in Fig. 25, and as the machine is, to a large extent, built up around this essential, its construction is taken up first. It consists of four long beams united by 35 crosspieces. The beams are of ash, 1 3/16 inches square for the first third of their length and tapering to 7/8 inch square at the rear ends. Owing to the difficulty of securing good pieces of wood the full length, and also to facilitate packing for shipment, the beams are made in halves, the abutting ends being joined by sleeves of 1 1/8-inch, 20-gauge steel tubing, each held on by two 1/8-inch bolts. Although the length of the fuselage is 21 feet 11 1/4 inches, the beams must be made of two 11-foot halves to allow for the curve at the rear ends.

Fig. 26. Details of U-bolt Which is a Feature of Bleriot Construction

The struts are also of ash, the majority of them being 7/8 by 1 1/4 inches, and oval in section except for an inch and a half at each end. But the first, second, and third struts (counting from the forward end) on each side, the first and second on the top, and the first strut on the bottom are 1 3/16 inches square, of the same stock as the main beams. Practically all of the struts are joined to the main beams by U-bolts, as shown by the detail drawing, Fig. 26, this being one of Louis Bleriot's inventions. The small struts are held by 1/8-inch bolts and the larger ones by 3/16-inch bolts. The ends of the struts must be slotted for these bolts, this being done by drilling three holes in a row with a 5/32- or 7/32-inch drill, according to whether the slot is for the smaller or larger size bolt. The wood between the holes is cut out with a sharp knife and the slot finished with a coarse, flat file.

All of the U-bolts measure 2 inches between the ends. The vertical struts are set 1 inch forward of the corresponding horizontal struts, so that the four holes through the beam at each joint are spaced 1 inch apart, alternately horizontal and vertical. To the projecting angles of the U-bolts are attached the diagonal truss wires, which cross all the rectangles of the fuselage, except that in which the driver sits. This trussing should be of 20-gauge piano wire (music-wire gauge) or 1/10-inch cable, except in the rectangles bounded by the large struts, where it should be 25-gauge piano wire or 3/32-inch cable. Each wire, of course, should have a turnbuckle. About 100 of these will be required, either of the spoke type or the regular type, with two screw eyes—the latter preferred.

Transverse squares, formed by the two horizontal and two vertical struts at each point, are also trussed with diagonal wires. Although turnbuckles are sometimes omitted on these wires, it takes considerable skill to get accurate adjustments without them. The extreme rear strut to which the rudder is attached, is not fastened in the usual way. It should be cut with tongues at top and bottom, fitting into notches in the ends of the beams, and the whole bound with straps of 20-gauge sheet steel, bolted through the beams with 1/8-inch bolts.

Continuing forward, the struts have no peculiarity until the upper horizontal one is reached, just behind the driver's seat. As it is impossible to truss the quadrangle forward of this strut, owing to the position of the driver's body, the strut is braced with a U-shaped half-round strip of 1/2 by 1 inch of ash or hickory bolted to the beams at the sides and to the strut at the rear, with two 1/8-inch bolts at each point. The front side of the strut should be left square where this brace is in contact with it. The brace should be steam bent with the curves on a 9-inch radius, and the half-round side on the inside of the curve.

The vertical struts just forward of the driver's seat carry the inner ends of the rear wing beams. Each beam is attached with a single bolt, giving the necessary freedom to rock up and down in warping the wings. The upper 6 inches of each of these struts fits into a socket designed to reinforce it. In the genuine Bleriot, this socket is an aluminum casting. However, a socket which many would regard as even better can be made from a 7-inch length of 20-gauge 1 1/8-inch square tubing. One end of the tube is sawed one inch through the corners; two opposite sides are then bent down at right angles to form flanges, and the other two sides sawed off. A 1- by 3-inch strip of 20-gauge sheet steel, brazed across the top and flanges completes the socket. With a little care, a very creditable socket can be made in this way. Finally, with the strut in place, a 3/8-inch hole is drilled through 4 inches from the top of the socket for the bolt securing the wing beam.

The upper horizontal strut at this point should be arched about six inches to give plenty of elbow room over the steering wheel. The bending should be done in a steam press. The strut should be 1 3/16 inches square, cut sufficiently long to allow for the curve, and fitted at the ends with sockets as described above, but set at an angle by sawing the square tube down further on one side than on the other.

On the two lower beams, is laid a floor of half-inch boards, extending one foot forward and one foot back of the center line of the horizontal strut. This floor may be of spruce, if it is desired to save a little weight, or of ordinary tongue-and-grooved floor boards, fastened to the beams with wood screws or bolts. The horizontal strut under this floor may be omitted, but its presence adds but little weight and completes the trussing. Across the top of the fuselage above the first upper horizontal strut, lies a steel tube which forms the sockets for the inner end of the front wing beams. This tube is 1 3/4 inches diameter, 18 gauge, and 26 3/4 inches long. It is held fast by two steel straps, 16 gauge and 1 inch wide, clamped down by the nuts of the vertical strut U-bolts. The center of the tube is, therefore, in line with the center of the vertical struts, not the horizontal ones. The U-bolts which make this attachment are, of course, the 3/16-inch size, and one inch longer on each end than usual. To make a neat job, the tube may be seated in wood blocks, suitably shaped, but these must not raise it more than a small fraction of an inch above the top of the fuselage, as this would increase the angle of incidence of the wings.