Influence on Aerodynamic Performance of a Compound Helicopter by Wing Incidence Angle

Abstract

This paper investigates the influence on aerodynamic performance of a winged compound helicopter due to change of the lift share ratio between a rotor and a wing through a numerical simulation. The lift share ratio is defined by the wing incidence angle. A compound helicopter model is constructed with the UH-60A helicopter rotor and the fuselage configuration, which is based on the JAXA scaled down model. The fuselage model combines the body with a rectangular wing of an aspect ratio of 10. Flight condition at a cruising speed corresponding to an advance ratio of 0.703 is simulated, where the rotor speed is reduced to 75% RPM. Numerical simulation results show that the aerodynamic performance degrades significantly by rotor/wing aerodynamic interaction, where a decreasing wing lift relates to a rotor thrust increase. To minimize the aerodynamic drag caused by the rotor/wing interaction, it is found that the wing should be installed at an incidence angle of the highest lift to drag ratio, and the wing area should be adjusted to satisfy the optimal rotor/wing lift ratio.