Full-Scale Wind Tunnel Test of a Helicopter Individual Blade Control System

A helicopter individual blade control (IBC) system was tested on a full-scale BO 105 rotor in the NASA Ames 40- by 80-Foot Wind Tunnel. For this test, the rotating pitchlinks were replaced by servo-actuators developed by ZF Luftfahrttechnik, Germany. Using these actuators, IBC inputs consisting of single-frequency harmonics (2P to 6P), pitch pulses, pitch wavelets, and doublet pitch schedules were introduced in an open-loop manner. IBC inputs of 1P-12P were also tested without blades. An extensive amount of data were acquired for each IBC data point. These data include rotor performance, vibratory hub forces and moments, blade loads, control system loads, blade root pitch motion, blade tip accelerations, and BVI noise data. These data indicate very significant reductions of all vibratory rotor forces and moments and suppression of BVI noise using IBC.