Aerodynamic effects of delta planform tip sails on wing performance

Abstract

An experimental investigation was conducted to establish the effects of delta planform tip sails (DPTSs) on a planar rectangular wing. The DPTS is a small wingtip-mounted device analogous to a conventional tip sail, but with a slender planform. It is suggested that using a sharp-edged, slender tip device may alleviate some of the design complexities (e.g., twist and camber) associated with keeping attached flow on winglets and tip sails. The results indicate that performance improvements can be obtained with DPTSs. Increases in the wing lift curve slope, maximum lift coefficient and, for some configurations, the Oswald efficiency factor were obtained compared to the basic wing. Increasing the DPTS leading-edge sweep angle and taper ratio resulted in an increase in the wing's Oswald efficiency factor.