Effect of Radial Load Distribution on the First-Harmonic Inflow Velocity of a Helicopter Rotor at Transition Speeds

摘要

A joint Navy/NASA experimental investigation was conducted in October 1983 in the Langley Research Center VSTOL Wind Tunnel to test the hypothesis that helicopters with unusually hub-weighted radial load distributions should experience a more severe first harmonic inflow velocity field during transition than ordinary helicopters. This report presents an approximate analysis of the experimental results. The hypothesis is strongly supported. Compared to the rotor configuration with the most tip-weighted load distribution, the configuration with the most hub-weighted distribution appears to have experienced an approximately 50 percent greater first-harmonic inflow at a 50 percent greater critical flight speed. (Author)