LOW-SPEED WIND-TUNNEL INVESTIGATION OF A TRIANGULAR SWEPTBACK AIR INLET IN THE

A low-speed investigation has been conducted in the Langley two-dimensional low-turbulence tunnel to study a sweptback wing-root air-inlet configuration believed suitable for transonic-speed jet-powered airplanes. The test configurations consisted of a basic model with an NACA 6U-OO8 wing with quarter-chord sweepback of k^> mounted in the mid-wing position on a fuselage of fineness ratio 6.7, and an inlet model which had a triangular-shaped sweptback inlet installed in the wing root, Installation of the wing-root inlet was accomplished with no significant effects on the force characteristics of the basic wing. The fuselage boundary layer entering the inlet was thin and required no boundary-layer-control device ahead of the inlet. Near unity inlet total-pressure recovery was obtained to about 86 percent of the maximum lift coefficient over a large range of inlet-velocity ratio. Maximum local velocities over the external surfaces of the inlet sections were no greater than those over the wing at a midspan station for the assumed high-speed operating conditions