Rotorcraft rotor blade with reduced acoustic signature

摘要

The main profile part (21) of the blade has a back swept tip (31) and adjacent intermediate section (32) with a forward sweep. The back swept tip of the blade covers a length equivalent to at least 0.15R, where R is the radius of the rotor measured from its axis of rotation to the blade tip (28). The adjacent intermediate section (32) of the rotor has a forward sweep. The inner sections (33,32a) of the rotor have a progressively increasing chord, while the outer sections (32b,31) have a progressively decreasing chord.