Helicopter rotor blades
AssigneeWestland Helicopters Limited
InventorsFrederick J. Perry, Nicholas C. G. Isaacs, Alan Brocklehurst
Life of this patent
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Abstract
Flow separation behind the notch region of a swept tip of a helicopter rotor blade is reduced by a plurality of boundary layer control vanes located adjacent a forwardly swept leading edge portion forming the notch region.
Claims18
A helicopter rotor blade having a leading edge and a trailing edge defining a blade chord, a pitch change axis, a swept tip including a forwardly swept leading edge blended with the blade leading edge to define a notch region, and a plurality of rearwardly extending boundary layer control vanes protruding from an upper aerofoil surface of the rotor blade and spaced-apart along the notch region, the control vanes comprising thin fences extending between leading and trailing edges thereof with the leading edges of at least some of the control vanes substantially coincident with said forwardly swept leading edge, and the lengths of the control vanes being between 5 percent and 40 percent of the blade chord dimension.
A helicopter rotor blade having a leading edge and a trailing edge defining a blade chord, a pitch change axis, a swept tip including a forwardly swept leading edge blended with the blade leading edge to define a notch region, and a plurality of rearwardly extending boundary layer control vanes comprising thin fences protruding from an upper aerofoil surface of the rotor blade and extending between leading and trailing edges, wherein a plurality of said control vanes are located in planes generally perpendicular to said pitch change axis and spaced-apart along the notch region with the leading edges of at lest some of said control vanes substantially coincident with said forwardly swept leading edge, and at least two additional boundary layer control vanes are located inboard of said control vanes extending from said forwardly swept leading edge.
Dependencies are inferred from the claim text.