Spanwise Distribution of Lift and Drag at High Angles of Attack 891019
Knowledge of the characteristics of finite span wings operating at high angles of attack is of importance in predicting post-stall performance of high performance aircraft, in studying problems associated with stall and spin departure of aircraft, and in predicting performance of wind turbines.
Experimental studies of reflection plane wings, in the wind tunnel and water tunnel, show that, below the stall, the spanwise distributions of lift and drag agree quite well with classic aerodynamic theory. At angles of attack above the stall, however, lift and drag distributions across the span are considerably different. Experimental results are presented which demonstrate these altered spanwise loadings.
The increase of lift toward the wingtip is partially the result of “side-edge” vortex lift. Use of drooped leading-edge extension cuffs further change the spanwise lift distribution above the wing stall angle. Based on these results, a new wing is being tested to develop a system of lateral control to be effective at angles of attack beyond the stall.