Abstract: A leading edge flap system for an airplane includes a flap which is rotated about a single hinge point between (i) a retracted position, (ii) an intermediate extended position for high speed maneuvering, and (iii) a fully extended position for low speed maneuvering. In the high speed intermediate position, there is no slot between the flap and the wing leading edge. This position provides additional lift to improve the airplane's turning performance. On the other hand, in the low speed fully extended position, the flap is rotated a greater amount than in the intermediate extended position. In this position there is a slot between the flap and the fixed leading edge to permit air to flow from the bottom of the flap upward and over the upper surface of the leading edge. This improves the lateral stability of the airplane when in a sideslip during stall conditions.

Abstract: An airfoil (10) having improved life capability and having airfoil curves including a camber divided into three regions I, II and III. Region I has a starting point aft and adjacent a leading edge (12) and encompasses the airfoil stagnation point. Region I has a high curvature around the leading edge and decreases aft along the chord to a first local minimum value of less than 3 for K times C, where C is the length of the chord and K is the reciprocal of the local radius of curvature. The curvature region II starts at the after end of region I within 10% of the chord length and the curvature in region II first increases from the first local minimum at the aft end of region I and then decreases to a second local minimum within 40% of the chord length.