The Power Profile - A New Type of Airfoil.
Technical rept. Apr 72-Nov 73,
DOUGLAS AIRCRAFT CO LONG BEACH CALIF
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A new concept in airfoils, termed power profiles, having a blunt trailing edge shape with two wall jets near the trailing edge is presented. The replacement of streamlining with properly designed blowing is used to prevent flow separation and additionally offers potential applications as a powered high-lift system, propulsive system, or low inertia control device. Exploratory wind tunnel tests of a 22.5 thick, 24-inch chord model with several control shapes were conducted and summarized. With high blowing power mode lift coefficients in excess of 8.0 were obtained, and with a very small amount of blowing boundary layer control mode unseparated flow and low drag was achieved. In the latter case blowing can be accomplished by natural ram air pressure and might serve as a substitute for streamlining. Applications of this concept and areas for additional study are outlined. Author