Influences of Mounting Angles and Locations on the Effects of Gurney Flaps

Experimental investig ations were conducted on a NACA0012 airfoil to determine the in uences of mounting angles and mounting locations on the lift-enhancing effects of Gurney aps at a Reynolds number of 2:1 £1 06 .The results revealed that all aps of different mounting angles increased the lift coefcient, and an increment of maximum lift coefcient of 1 2.3, 15.1, and 17.4% was obtained by 45-, 60-, and 90-deg Gurneyap, respectively.There was a drag penalty associated with the lift enhancement. The best perfo rmance was obtained by the 45-deg Gurneyap for all apde ections tested. When shifted forward from the trailing edge of the airfoil, the Gurney apled to a decrease in lift, a nd an increment in drag, and thus a reduction in liftto-drag ratio