Movable tip strakes and wing aerodynamics

A wind-tunnel study of the effects of the addition of movable tip strakes on the aerodynamic characteristics of a rectangular wing model has been conducted. This is a new application of the strake concept for modifying the flowfield around a wing. The addition of sharp-edged slender delta-wing-shaped strakes significantly modified the flow pattern in the vicinity of the wing through generation of vortex lift. The strakes improved the lift-to-drag ratio of the baseline wing by as much as 23%. The method can have potential for lateral control too. Based on limited flow-visualization results, it appears that the strakes favorably influence the near-field roll up of the wing trailing vortices. The approach warrants additional investigations using more advanced measurement and flow-visualization techniques.