Abstract:
Calculations of the efficiency of propellors having five different thickness distributions (effects of other variants having been eliminated) have been made for forward speeds from 300 to 600 m.p.h. at 20,000 ft. It is shown that the efficiency becomes very sensitive to the thickness (particularly of the root end of the blade) as the speed is increased beyond 500 m.p.h., but that at this speed the effects of tip thickness are relatively minor provided the blade is at least as thin as, say, a modern compressed propellor.