Aerodynamic Interaction between a Rotor and a Wing on Compound Helicopter in Forward Flights

Abstract

This paper investigates the influence on aerodynamic performance of the rotor/winged-body configuration due to change of advance ratio and the lift share ratio between a rotor and a wing through numerical simulations. A computational model of compound helicopter is constructed with a main rotor of UH-60A helicopter and a winged-body configuration where the fuselage is designed by JAXA and the wing is rectangular. Flight conditions at various cruising speed corresponding to an advance ratio of 0.1 to 0.7 is simulated. As a result, the flow around the wing is deflected in a direction of decreasing angle of attack. This trend becomes stronger as the advance ratio decreases. The lift share of the rotor increases between 0.05 and 0.08 at the advance ratio of 0.1 to 0.7. The total effective drag coefficient increases due to the aerodynamic interaction, the increase of the rotor effective drag coefficient is greater than that of the winged-body. The drag coefficient of the wing of the winged-body becomes negative at the advance ratio of 0.1 and 0.15. The rotor effective drag coefficient and the winged-body drag coefficient increase significantly at high advance ratio. Therefore, the total effective lift-to-drag ratio decreases as the advance ratio increases, and it decreases by 18% at the advance ratio of 0.7. In addition, the advance ratio of the maximum total lift-drag ratio is smaller than that designed without aerodynamic interaction between the rotor and wing-body.