Patent ID: 6190132
Filing Date: 2001-02-20
Classification: B64C,Y10S

Abstract:
A rotor blade for a rotorcraft comprising:a blade root portion which is to be attached to a rotor head for rotating;a center portion which linearly elongates from the blade root portion; anda blade tip portion which has a shape and a predetermined aerofoil, the shape elongating outward from the center portion and being defined by a leading edge, a side edge, and a trailing edge,wherein in the leading edge of the blade tip portion, a swept-back angle .lambda.(r) at a distance r from a rotation center of a rotor satisfies the following relational expression (1): ##EQU3##where R is a rotor blade length of the rotorcraft, M.sub..infin. is a maximum flight Mach number which is a flight limit speed of the rotorcraft, M.sub.TIP is a blade tip Mach number which is a tip speed during hovering, and M.sub.dd is a drag divergence Mach number determined from the aerofoil of the blade tip portion.