Abstract: The present invention relates to a blade section for rotating wings of an aircraft comprising, between the leading edge and the trailing edge, a convex lower surface and an upper surface which is convex over the greater part of its length, but concave near the trailing edge. According to the invention, the upper surface of the section comprises a region of small extent, close to the leading edge but not contiguous thereto, in which the curvature is substantially constant. The invention is applicable to the improvement of the performances in maneuvering flight, while hovering and in advance flight of the aircraft.

Abstract: The present invention relates to a high performance blade for helicopter rotor presenting an aerodynamic surface produced by profiles of which the aerodynamic twist increases from the end profile towards the root profile and is then reversed and becomes zero at the fastenings of the blade. According to the invention, the angle of twist formed by the zero lift chord C.sub.o of a profile of the aerodynamic surface and a reference plane P passing through the center of the fastenings of the blade to the hub of the rotor, is, for the end profile, at the most equal to a value .theta..sub.1 of 0.3 degrees. The invention is more particularly applied to the obtaining of rotary wings, for example for helicopters, capable of very high performances, particularly in rapid forward flight under high load.