Empirical relation between induced velocity, thrust, and rate of descent of a helicopter rotor as determined by wind-tunnel tests on four model rotors

Walter Castles, Jr., Robin B. Gray
naca-tn-2474
Oct 1951


the empirical relation between the induced velocity, thrust, and rate of vertical descent of a helicopter rotor was calculated from wind-tunnel force tests on four model rotors by the application of blade-element theory to the measured values of the thrust, torque, blade angle, and equivalent free-stream rate of descent.

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