SUPERCRITICAL AIRFOIL SECTIONS WITH SLOTLESS FOWLER FLAPS FOR GLIDERS AND MOTORGLIDERS

Abstract

In general, our supercritical airfoils show a more gradual increase in velocity on the suction side than conventional Fowler flap airfoils. The pressure does not peak at the leading edge, but rather is distributed over the entire airfoil. Thus, lift is distributed over much more of the wing chord. Since the drag is proportional to the square of the velocity, by reducing the size of the pressure peak, the drag is reduced. And, since the pressure is distributed farther over the airfoil surface, lift is increased. This combination of reduced drag and increased lift results in smaller wings with less drag and less weight, or higher payloads may be carried as it has been demonstrated in motorgliders and two-place gliders for training purposes. The feasibility of such airfoils for highly efficient sailplanes remains to be demonstrated.