Wind Tunnel Test of Five Sets of Mach Scale Composite Tailored Rotor with Flap-Bending/Torsion Couplings for Vibration Reduction

摘要

Five sets of Mach scale composite tailored rotors were designed and fabricated, including a baseline rotor without coupling, two rotors with uniform spanwise flap-bending/torsion coupling, and two rotors with spanwise segmented (mixed) flap-bending/torsion coupling. The rotors were tested at 2000 and 2300 rpm (hover tip Mach number 0.65) at different advance ratios and thrust levels in the Glenn L. Martin Wind Tunnel at the University of Maryland. The test results show that the flap-bending/torsion couplings have a significant effect on the fixed frame vibratory rotor hub loads. The 4/rev vertical hub force was reduced for combinations of composite coupling, rotor speed, and advance ratios of 0.1, 0.2, and 0.3, with reductions ranging from 1% to 58% (although sometimes with increases in other hub loads). However, the composite coupled rotor with the spanwise dual-segmented flap-bending/torsion coupling reduced overall 4/rev vibratory hub loads at advance ratios of 0.1, 0.2, and 0.3. At 2300 rpm and 0.3 advance ratio, the 4/rev vertical hub force was reduced by 15%, the inplane hub force by 3%, and the head moment by 14%. The reductions in rotor vibratory hub loads are related to the experimentally observed reductions in blade 3 and 5/rev flap-bending moments.