Performance Improvements with the Free-Tip Rotor

Free-Tip rotor was investigated for its potential to improve helicopter forward-flight performance characteristics. This rotor differs from a conventional rotor only in the blade tip region. The Free Tip is self-adjusting in pitch with respect to the rest of the blade. With this capability, the resulting pitch motion generated a more uniform airload distribution around the azimuth. Computer math models were used to compare performance characteristics of the Free Tip rotor with those of a conventional rotor operating at flight speeds from 130 to 160 knots. The Free Tip rotor is shown to improve cruise L/DE by at least 22%.