Note 40 — Chapter III · EXPERIMENTS WITH MODELS

See “Experiments in Aerodynamics.” It will be recalled that in the experiments with the “plane-dropper” there was a greatly reduced lifting power with superposed planes when their distance apart was one-half the width the planes, unless a speed of about 42.5 feet a second was obtained. In the above tests with the superposed wings, the speed was only from twenty to twenty-two feet a second at the time of launching, and as the distance between the surfaces was only one-half as great as their width, it is not surprising that the lifting power should not be as great as with the “single-tier” wings.