摘要 |
<p>Flow separation behind the notch region (21) of a swept tip (12) of a helicopter rotor blade (11) 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 (16) to extend at an angle between 30 degrees and 55 degrees from a reference line parallel to a blade pitch change axis (31) and the leading edge of the aerofoil in the notch region incorporates blade droop (30).</p> |