| 摘要 |
PURPOSE: To provide a helicopter rotor blade forming two approximately equal strength vortices which can be separately lest as long as possible in operation and characterized in that the helicopter rotor blade can maintain the flow adhered on a top end of the blode so as to avoid a drag penalty. CONSTITUTION: This helicopter rotor blade is provided with, at its tip end, a tip vane having a mean blade chord length greater than 50% of a blade chord length of a blade central portion and a span length greater than 50% of the blade chord, which in operation generates two approximately equal strength tip vortices to reduce an acoustic impulse and a resulting noise known as blade slap. |
