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This kite is given its name because its backbone is divided into two curved prongs at the top. It has the double advantage of being bow shaped, and possessing a large sail area. The operator will find that it will move in a lively manner. Correct balance and shape are essential for successful flying. These are achieved by paying careful attention to all the constructional details. It is one of the largest kites described in the book, consequently the bridle and kite line must be correspondingly strong.
The backbone, A, is 3 ft. 6 in. in length. Use 3/8 in. square strip-wood, which should be straight and smooth, and free from knots or any other defect. Notch the ends as shown (Fig. 9) and with a fine fretsaw blade saw down from the top end to a depth of 6 in. This makes two prongs, which are bent to a fork shape. First, soak the prongs in water for about an hour. Then bind round the backbone just below the prongs with strong thread. This will prevent the saw cut from developing into a split. Now, gently but firmly prise the prongs apart, and insert a wedge at the top of the opening. Use a piece of stripwood 3/8 in. square x 1 in. Glue and nail it in place, and drill small holes to start the fretwork nails, which are 1/2 in. long.
The crossbar, B, is 3 ft. in length. Use split cane about \ in. thick, or as an alternative, 1/4 in. square stripwood. The ends are grooved and two small holes are drilled through, 1/2 in. from each end. Following this, the crossbar is curved to a bow shape. If cane is used, apply dry heat, for example, a gas jet, whilst bending it. This will stop it splitting. Soaking for a while in water is recommended if stripwood is used. See the section on 'Methods' in Chapter 7.
Details of the shaping are as follows. Take a length of good
quality string. Thread it through one of the holes and tie it, leaving a 5 in. tail to the knot. Pass the string over the end of the crossbar and over to the other end, where it is threaded through the second hole. Applying firm pressure, bend the crossbar to a curve. To do this rest one end of it on the floor. Press firmly downwards, at the same time drawing the string taut. Bind the end of this once or twice round the crossbar and tie. The depth of the curve at the centre should be about 3 in. This bowstring has to withstand considerable strain so make sure that it is tough.
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