Blade profile for rotary-wing aircraft.

摘要

1. A blade profile for rotary wing of an air-craft, comprising between the leading edge (0) and the trailing edge (8), a convex upper surface (2) and a non-concave lower surface (3), characterized in that at the point (0) of maximum curvature of the leading edge, the radius of curvature Ro is approximately defined by the expression Ro=1.7 C.e**2 max , in which C represents the chord and emax the maximum relative thickness of said profile, that the portion of lower surface (13) adjacent said leading edge (0) comprises a first lower surface zone (13-1) immediately adjacent the leading edge (0) and extending at the most over 5% of the chord C, in which the curvature decreases rapidly in the direction of the trailing edge from the value 1/Ro to a value equal to about 0,02/Ro and a second lower surface zone (13-2) prolonging the first and extending up to about 20% of the chord from said leading edge (0), this second lower surface zone (13-2) having a general curvature inferior to the smallest curvature of said first zone and decreasing continuously in the direction of the trailing edge (8) up to a point of minimum curvature f which is located at the end of said second zone (13-2).