THE SM701 AIRFOIL: AN AIR FOIL FOR WORLD CLASS SAILPANES

Abstract

In 1989, the Intenational Gliding Commission (IGC) of the Federation Aeronautique Intemationale (FAI) created a new class of sailplanes, the World Class. The goals of this class are significantly different from those of the Standard, l5-Meter, and Open Classes. Accordingly, the performance of existing airfoils does not provide a good match to the requirements of World Class sailplanes. Therefore, a 16-percent-thick, laminar flow airfoil has been designed specifically for World Class sailplanes. This paper is a condensation of  the report entitled "The SM701 Airfoil." The airfoil has been designed and analyzed theoretically. As verified by wind-tunnel measurements, the primary objectives of a high maximum lift coefficient and low piofile-drag coefficients, with restrained pitching-mornent coefficient, have been achieved. In addition, the airfoil should exhibit docile stall characteristics. An analysis of a generic World Class sailplane incorporating the SM701 airfoil confirms the achievement of the objectives.