[Fig. 123] shows the model in perspective.
CHAPTER XII
Hydro-monoplane
The present machine is capable of making a flight of about sixty seconds after rising from the water, which it does after travelling from 8 ft. to 10 ft. under normal conditions. This model is what is known as the “A” frame ([see Chapter III].) type of monoplane fitted with a loaded elevator.
The framework or fuselage is not constructed in quite the orthodox manner, but in the manner shown in section at D and E ([Fig. 124]). These side members are made from two pieces of best silver spruce 3 ft. 3 in. long, ⅜ in. by ¼ in. at the forward or elevator end, ½ in. by ¼ in. in the middle, between the elevator and the main plane, and ⅜ in. by ³/₁₆ in. at the propeller end. This tapering is necessary in order to make the wood proportionate to the strain to which it will be subjected. This is called a cantilever. After each stick has been planed to the above sizes, a hollow chisel is used to channel out the wood on one side, the finish being given with a woodworker’s file. The opposite side is rounded off after the inside is finished. The front ends are bound together and glued, the forward hooks (to which the rubber is attached), and the protector, shown by [Fig. 125], being incorporated at the same time; these are made of No. 18 and No. 20 s.w.g. piano wire respectively.
The other extremity of the fuselage is held 9½ in. apart by means of a bamboo distance strut, measuring ³/16 in. by ¹/16 in. This strut, together with the three others, is carefully shaped, the ends sharpened, and then fitted into a split in the side members as indicated in [Fig. 126]. Considerable care is needed in making this form of joint; but when the joints are glued and bound over with ¼-in. strip silk, they are wonderfully strong.
The propeller bearings are made of No. 18 s.w.g. wire, and resemble a lady’s plain hairpin bent at right angles midway, with a cupped washer soldered on the round end to take the thrust ([see Fig. 127]). These washers, known as French clock collets or cupped washers, may be procured at any watch repairer’s at 3d. per dozen. The propeller bearings should be bound to the fuselage at the same time as the end distance piece is fixed. The frame is trussed with two diagonal bracing wires; No. 30 s.w.g. piano wire should be used, this being strained with the aid of hooks as shown in [Fig. 128]. To tighten the wire, twist the hooks with a pair of round-nose pliers.
The main plane is 37 in. in span, with a maximum width of 7 in. at the centre, tapering to 6 in. at 3 in. from the tip. The camber is ¾ in. at the centre and ⅜ in. near the tip. The frame is constructed of bamboo, the leading edge and the end ribs being one long piece of selected yellow bamboo, ³/₁₆ in. by ³/₃₂ in., and is bent to the shape by holding over an incandescent gas burner. The trailing edge is made of similar material; but is straight when looked at in plan. This piece measures 34 in. by ³/₁₆ in. by ³/₃₂ in., and is joined to the end ribs as shown at C ([Fig. 129]), afterwards being bound with strip silk. The ribs are all ³/₁₆ in. by ¹/₁₆ in., being bent in the manner suggested above and split-jointed into the spars.
Fig. 124.—Plan
