NONSENSE OF WINGLETS

Abstract

To my knowledge, three rather successful approaches have been tried to improve the performance of gliders by the use of winglets. The examples I refer to are: The ASW 19 from Akaflieg Braunschweig, as an example for a standard class glider; the ASW 20FP from Centrair, as an example for the FAI l5-meter class; and the ASW 22 (22m span version) of Walter Neubert. The advantage of winglets for low speed performance has been proven by all the gliders mentioned above. The reason for this is that the induced drag is reduced even less than the value for an elliptic straight wing of the same span. It must be carefully regarded and kept in mind that this advantage is gained by a normally negligible increase in bending moment of the wing in the highly loaded areas near the wing root. However, the advantage at low speeds is partially compensated, or even overcompensated, by additional drag at high speeds.