EFFECT OF ROTOR WAKE ON AERODYNAMIC CHARACTERISTICS OF A 1/6-SCALE MODEL OF THE ROTOR SYSTEMS RESEARCH AIRCRAFT

摘要

A wind-tunnel investigation was conducted to determine the effect of the main-rotor wake on the aerodynamic characteristics of the rotor systems research aircraft (RSRA). A 1/6-scale model with a 4-blade articulated rotor was used to determine the effect of the rotor wake for the compound configuration. Data were obtained over a range of angles of attack, angles of sideslip, auxiliary engine thrusts, rotor collective pitch angles, and rotor tip-path plane angles for several main-rotor advance ratios. Separate results are presented for the forces and moments on the airframe, the wing, and the tail.nThe results of this investigation indicate that the aerodynamic charac-teristics are significantly changed by the rotor wake. The rotor wake increases the longitudinal static stability, the effective dihedral, and the lateral static stability of the airframe. The rotor induces a downwash on the wing. This downwash decreases the wing lift and increases the drag. The asymmetrical rotor wake induces a differential lift across the wing and a subsequent rolling moment. These rotor induced effects on the wing become smaller with increasing forward speed.