Movi-ng-Surface Boundary-Layer Control for Aircraft Operation at High Incidence

Abstract

The paper studies effectiveness of the moving-surface boundary-layer control on a NACA 63-218 (modified) two-dimensional wing used in the Canadair CL-84, a twin-propeller V/STOL design. Tests with rotating cylinder(s) at the leading edge of the airfoil and/or of the flap show the former to have a significant effect on the maximum lift, stall characteristics, and lift/drag ratio. On the other hand, the advantage gained by the presence of the rear cylinder is relatively small for the slotted flap configuration. The availability of a high value of lift suggests the approach velocity with this form of boundary-layer control is likely to be limited only by the lateraldirectional stability characteristics. The concept presents several possible applications including a mechanism for delaying the vortex-induced resonance of bluff bodies.