Helicopter rotor blades
AssigneeWestland Helicopters Limited
InventorAlan 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 features of the geometry and aerodynamic characteristics of the notch region itself. In particular it has been found beneficial for a forwardly swept leading edge portion to extend at an angle between 30 degrees and 55 degrees from a reference line parallel to a blade pitch change axis and the leading edge of the aerofoil in the notch region incorporates blade droop.
Claims4
A helicopter rotor blade having a leading edge and a trailing edge defining a blade chord, a pitch change axis and a swept tip of aerofoil section and having a forwardly swept leading edge including a central portion blended respectively with the blade leading edge and a tip rearwardly swept leading edge by inboard and outboard blend curves to define a notch region wherein said forwardly swept leading edge central portion extends at an angle between 30 degrees and 55 degrees from a reference line parallel to the blade pitch change axis and the leading edge of the aerofoil section in the notch region incorporates blade droop.
Dependencies are inferred from the claim text.