EXPERIMENTAL INVESTIGATION OF ROTOR LIFTING SURFACE INTERACTIONS

Experiments were conducted to study the aerodynamic interactions betwe en a rotor and a fixed lifting surface. A low aspect ratio rectangular wing was positioned at different locations in a rotor flowfield to si mulate the aerodynamic environment encountered by the wings of tilt-ro tors or the empennage of helicopters. Steady and unsteady pressure mea surements were made on the wing at various chordwise and spanwise stat ions for different combinations of rotor thrust and advance ratio. Flo w visualization was performed using the wide-field shadowgraph method, which helped to identify the locations of the rotor wake relative to the rotor and wing. The results have shown that the lifting surface op erates in a highly unsteady three-dimensional now environment with reg ions of partial or complete now separation. In addition, large unstead y loads were induced on the wing by the rotor and its wake.