초록 ▼

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

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 Co 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 q1 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.

대표청구항 ▼

A high performance blade for a helicopter rotor having a hub, comprising: at one end of said blade, an end profile disposed perpendicularly to the leading edge of the blade; at the other end of said blade, means for fastening said blade to said hub; a root profile located between said end profile an

A high performance blade for a helicopter rotor having a hub, comprising: at one end of said blade, an end profile disposed perpendicularly to the leading edge of the blade; at the other end of said blade, means for fastening said blade to said hub; a root profile located between said end profile and said other end, said end profile and said root profile defining along the major part of the span of the blade an aerodynamic surface produced by profiles of substantially constant chord, each profile having a radius of maximum curvature Ro at the leading edge defined approximately by the expression Ro=1.7 Ce2max, in which C represents the chord and emax the maximum relative thickness of the profile, and a point of minimum curvature positioned on the lower surface at a distance from the leading edge approximately equal to 20% of the length of the chord of said profile, said aerodynamic surface having an aerodynamic twist which increases linearly from said end profile to a maximum at said root profile, said twist then being reversed to become zero at said opposite end of the blade, the angle of twist formed by a zero lift chord of the end profile of said aerodynamic surface and a plane of reference passing through the centre of the hub of the rotor being positive and not more than 0.3 degrees, the difference between the angles of twist of the root profile and of the end profile being 6°-8°, and the distance separating said end profile from said root profile being at least equal to 70% of the length of the blade.