Experimental Investigation of Lift-Enhancing Tabs on a Two-Element Airfoil

An experimental investigation of the effect of lift-enhancing tabs on a two-element airfoil was conducted in the NASA Ames 7- by 10-Foot Wind Tunnel. When the flow over the flap upper surface is attached, tabs mounted at the main element trailing edge (cove tabs) produce very little change in lift. At high flap deflections, however, the flow over the flap is separated and cove tabs produce large increases in lift and corresponding reductions in drag by eliminating the separated flow. Tabs attached to the flap trailing edge (flap tabs) are effective at increasing lift without significantly increasing drag. The combination of cove and flap tabs provide additional options for optimization of multi-element airfoils for high lift.