Lift augmentation on delta wing with leading-edge fences and Gurney flap

A wind-tunnel experiment was conducted on a 60-deg delta wing st low speeds and low angles of attack to determine the lift augmentation effects of the leading-edge fences and a Gurney flap. Lift, drag, pitching moment, and surface pressures were measured, accompanied by vapor and oil-film flow visualizations. Both the leading-edge fences and the Gurney flap increase lift. They are shown to shift the lift curve by as much as 5 and 10 deg, respectively. The fences aid in trapping vortices on the upper surface, thereby increasing suction. The Gurney flap, on the other hand, improves circulation at the trailing edge. The lift augmentation effects of these two devices are roughly additive, resulting in high lift gain.