International Aviation Cup Defender Desiǵn
IN the design of an aeroplane, five different quantities must be considered, the speed through the air, total weight in order of flight, power required, surface of sup port and head resistance including skin friction. To arrive at the correct relationship of these elements that the design must have in order to produce an aeroplane capable of the highest speed, is the problem under con sideration. The speed attained in the last Gordon-Bennett race was about 80 miles per hour. Recently the
... Recently the world's record was broken when the speed attained was more than 93 miles per hour, with a 70 h ' orse-power motor. 1 There is no reason to doubt the assumption that the winner of the next race must be able to exceed a speed of 100 miles per hour. As a starting point in the design, it is necessary to assume that the proposed machine shall have a speed of at least 110 miles per hour. The efficiency curves as given by Eiffel for the different wing areas and sections of the Bleriot, Nieuport, Tatin, Breguet and R. E. P., show but a :;mall variation, hardly more than 15 per cent difference between the least effi cient and the best. That is to say, when these different wing sections are compared, they will lift about the same with equal head resistance, although they may be travel ing at diffe�nt speeds and have different angles of inci dence. Generally speaking, the higher the speed the less the camber of the wing and angle of incidence necessary for support, so that the higher the speed the less power required for support. This is clearly shown in Fig. 3 on the design chart by curve No. 1, where the resistance of the planes becomes less and less as the speed is increased.