Rotor/Airframe Aerodynamic Interference On The V-22 Tilt Rotor

The velocity field at the plane of the rotor disk of the V-22 tilt rotor is analyzed using a detailed fuselage/wing/nacelle panel method. Rotor inflow velocities are input to an aeroelastic rotor analysis to determine the aerodynamic proprotor loads induced by the wing during airplane mode flight. It is shown that by including the wing/rotor interference effects in conventional aeroelastic rotor analyses, higher frequency blade loads are accurately predicted. Sensitivities to parameters such as airspeed, angle of attack, and proprotor to wing spacing are discussed. Correlation of oscillatory blade loads is shown between theory and wind tunnel data for the 0. 2 scale V-22 aeroelastic model. Comparisons are also shown with an analysis which uses a Joukowsky transformation technique to calculate the induced flow field by superimposing the effects of wing thickness and circulation. The latter method is shown to be a good approximation to the complex flow conditions.