The Box Kite
This is probably the best known and most popular of all kites. It is an excellent flyer, and is made to withstand rough weather. No difficulty will be met with in constructing one, if the instructions are followed carefully. The four corner pieces, called longerons, A, B, C, D, are formed from stripwood, or other wood which can be cut to size. They are 3/8 in. square and 3 ft. 6 in. in length, and should be straight, smooth and free from knots. It is advisable to give them a coat of clear varnish, and then put on one side to dry. The four diagonal struts are approximately 2 ft. 1 in. in length, E and F. They can be made from either 1/4 in. x 1/2 in. stripwood, or plywood. These, too, should be varnished. They are cut somewhat longer than the actual measurement. When the kite is being assembled, they can be trimmed to give a really tight fit. This will ensure something which is really essential - firm cloth bands. Two cloth bands are required, of which one, G, is shown in Fig. 19. In the illustration, the front band has been removed, so that details of the framework may be seen more clearly.
The bands are made from lightweight material, which at the same time must be strong. Cambric or fine calico is recommended. Each measures 6 ft. 1 in. in length and 1 ft. 1 in. in width. Form a hem along the two long sides, for which 1/2 in. turning has been allowed. Sew the two long sides first. Then make a 1 in. turn along the two short ends, and oversew together. You have now two endless bands, each measuring 6 ft. x 1 ft. They should be free from wrinkles (see Fig. 19, H). The next stage is to lay them flat on the table, and with a hot iron, smooth them out, making creases at the folds. Fold them over again, and repeat the action with the iron. The bands will now have four creases, at intervals of 18 in. These indicate the position of the longerons. Place the first longeron along the crease made at the oversewn ends of the band. Fasten together with 3/8 in. fine brass screws. Repeat the process with the other longerons, one edge of each fitting snugly into the crease provided. Care must be taken in assembling the bands. Do not wrinkle or tear the material.
Now take one of the diagonal struts. Mark the exact centre. Drill through with a 1/8 in. diameter bit. Place this strut on top of a second, and join them together with a fine-gauge screw. The diameter of the hole is slightly larger than that of the screw, to enable the two struts to open and close freely. Care is needed to avoid splitting the wood. To help prevent this, apply a little light machine oil at the spots where the drilling and screwing take place. The ends of the struts are cut V-shaped, as shown at I (Fig. 19), and are bound round with strong thread, to prevent splitting, when the kite is assembled. Apply a little glue where you bind the strut. This will keep the thread permanently in position. The best method of inserting the struts is as follows. Get someone to open the kite out, stand it on end, and hold it squarely in place. This will enable you to slide the struts down until they are 5 in. from the ends of the longerons. As the struts were cut slightly oversize, it might be necessary to trim the ends. The thing to aim at is, that when the struts are fixed they will be bowed a little. This will exert maximum pressure on the longerons, and so keep the bands really taut. To prevent the struts slipping out of position, secure small L-shaped blocks to the longerons. Use glue and one fine panel pin for each block (see Fig. 19, J).
The bridle is fastened to one of the longerons in the form of a loop, K. It is 6 in. from either end. Use really strong string. A piece 7 ft. 6 in. in length will be required. In attaching the bridle it is necessary to pierce the bands. In order to strengthen them at these points, glue strips of material to the bands, thus providing a double thickness. The stiffening supplied by the glued strip will prevent tears and fraying. The kite line is attached to the bridle by means of a reef knot and a bowline knot.
The method of tying these is shown in Fig. 19, L. In this way the kite line can be adjusted on the bridle, to suit varying weather conditions. Generally speaking, such adjustments mean that the lighter the wind, the shorter the front line of the bridle will be. In a very strong wind, it might be necessary to tie the kite line directly to the longeron, just behind the front band. This would be at the point marked X. It must be emphasized that a really strong kite line is needed. It must be capable of withstanding considerable strain. Do not be tempted to use string of inferior quality. The price usually paid for this is a lost kite. The appearance of the kite is enhanced if the wooden framework is enamelled in suitable colours. In addition, designs could be painted on the bands. Students' oil colours may be used. A choice of designs is given in Chapter 7. This work would have to be done, of course, before the kite was assembled.