Page:Kitecraft and kite tournaments (1914).djvu/53

Rh kite like Fig. 71 might be evolved. But there is no great gain and much hindrance in some of these complications. If there is insufficient room between upper and lower surface, not all of the surface is exposed and there is skin friction, again if there is not space enough between the fore and back cells, the front cuts off the air pressure to some extent on the back cells. So Fig. 72 is not high enough, while Fig. 73 has the fore and back cells too close together. Fig. 74 is very unstable in the air.

The triangular cross-section has the advantage of a bracing framework and is easy in combination. The bridle is attached to one of the long sticks and the kite rides on a keel, Fig. 75. Three braces about the middle of each cell keep the corner sticks out to place. These can be put in at the field, thus allowing the kite to be rolled for transportation. The triangular kite is sometimes lengthened so as to use three cells, Fig. 76, and again two kites are placed side by side, Fig. 77, and this may be increased by placing another below both, as in Fig. 78. In the last combination we have a large kite to the outside and a smaller one to the inside which can be lengthened so as to give three cells in length, Fig. 79, and many other combinations can be made.

Tetrahedral Kite. Out of the triangular has grown the celebrated Bell tetrahedral kites, which can be increased in size beyond that of any other kite. No attempt will be made to give an exhaustive description or full construction of these wonderful kites as Dr. Bell has written a number of good articles on the subject for the Scientific American and other magazines. There have been some wonderful kites made on this principle of construction. In simple kites of this construction we have a large tetrahedral frame composed of six sticks, Fig. 80. Owing to the bracing effect, remarkably small material can be used. For a kite four feet to an edge, ″ sticks were ample. All of the drawings given