Investigation of Aeroelastically Adaptive Rotors.

摘要

Basic principles of aeroelastically adaptive rotor systems have been investigated by wind tunnel test and theory. These are helicopter rotor systems in which dynamic blade twist is enhanced and managed to extend rotor operating limits to higher lifts and advance ratios. In wind tunnel testing,dynamic twist was induced in blades of relatively low torsional stiffness using two design features shown by theoretical analysis to have significant potential:airfoil pitching moment and blade planform sweep with the sweep apex near midspan. Effects on trim flying qualities,fatigue loads,and aerodynamic efficiency were measured. Theory was used to explore specific design applications and to assess potential for productivity improvement. (Author)