Effects of variable sinusoidal leading-edge on the aerodynamic performance of a straight wing

Force measurements were carried out in a low speed wind tunnel to examine the aerodynamic performance of a straight wing installed with different wave-like variable sinusoidal leading-edges, which imitated the leading-edges of a humpback's flipper. The variable sinusoidal leading-edges were made of aluminum plate and placed in the slot which was assigned along the leading-edge of the wing. These variable leading edges can be extended and retracted according to different flying conditions. Results have shown that with the installation of variable sinusoidal leading-edges, "gradual stall" characteristic and lift enhancement after stall can be obtained; and the lift performance of the straight wing at high angle of attack is highly improved. The results also indicate that only when the extend length of the variable sinusoidal leading-edge is short, better aerodynamic performance for the straight wing can be achieved.