Slowed Hingeless Rotor Wind Tunnel Tests and Validation at High Advance Ratios

In forward flight, slowing down a rotor alleviates compressibility effects on the advancing side blade tip, extending cruise speed limit, and inducing high-advance-ratio flight regime. Previous wind tunnel tests have shown that an articulated trimmed to zero hub moment generates limited thrust at high advance ratios, because needs be against retreating with significant reverse flow, where is ineffective in generating thrust. A rigid hingeless lift offset may help overcoming this problem. series of were conducted investigate behavior slowed rotors ratios. Performance, control angles, vibratory loads, structural loads measured compared comprehensive analysis predictions. The results demonstrate more efficient exhibits higher lift-to-drag ratio load level significantly rotor, especially its flap bending moment, which can pose critical constraint rotor.