An experimental investigation of an airfoil pitching at moderate to high rates to large angles of attack

An experimental investigation of the variation in aerodynamic performance of a NACA 0015 airfoil over a range of constant pitching rates was performed in the Texas Tech tow-tank facility. The test results consist of flow visualization data, surface pressure measurements, and load cell data, and encompass a wide range of non-dimensional pitching rates [ K = dc/2Uoo) varying from 0.1 to 1.0 at angles of attack from 0** to 90°. The test Reynolds number was 100,000. These data have yielded several interesting physical correlations associated with large-scale pitch rate motions. Included in these are simple trigonometric correlations for the lift and drag forces and an extension of the Gormont model for the inception of leading edge separation. Very large lift and drag coefficients on the order of 10 have been generated. These large forces, produced by unsteady effects, may perhaps be exploited in the supermaneuverability concept for fighter aircraft.