Patent ID: 7891610

Claim:
A method of reducing a hinge moment of a flap ( 1 ) on a helicopter rotor blade ( 3 ), the method comprising the steps of: providing the flap with a profile that includes an inner surface ( 9 ) and an outer surface ( 10 ) that have, beyond 25% of a chord (CO) of the flap, shapes that are not concave; providing the flap with a first trailing edge ( 8 ) that has a main angle (α) between 10° and 30°; setting a longitudinal axis of rotation ( 4 ) of the flap at a first distance (C 1 ) from a first leading edge ( 7 ) of the flap, the first distance being between 15% and 35% of the chord of the flap; attaching the flap ( 1 ) to a trailing edge ( 2 ) of the helicopter rotor blade ( 3 ) so that the flap turns about the longitudinal axis of rotation ( 4 ); and steering the flap relative to the helicopter rotor blade during rotation of the rotor blade while preserving an aerodynamic efficiency of the flap.