Experimental study on lift enhancement of supercritical airfoil in subsonic by Gurney flap

The effect of Gurney flap on the aerodynamic characteristics of a subsonic supercritical airfoil was investigated by force measurements in a two dimensional wind tunnel. The results indicate that the Gurney flap can increase the lift and nose down pitching moment of the supercritical airfoil in subsonic. The optimal lift to drag ratio is achieved with a Gurney flap height 0.5% of the airfoil chord length. Compared with the symmetrical airfoil NACA 0012, the lift increment of the supercritical airfoil induced by Gurney flap is larger, but the pitching down moment increment is in the opposite way.