Patent ID: 8186629
Filing Date: 2012-05-29
Classification: B64C

Abstract:
1. A method of optimizing the operation of a left propeller ( 21 ) and a right propeller ( 22 ) disposed on either side of the fuselage ( 2 ) of a rotorcraft ( 1 ) and suitable for generating respective propulsive air streams ( 21 ″, 22 ″), said rotorcraft ( 1 ) having a main lift rotor ( 10 ) and a power plant ( 5 ) suitable for setting said left and right propellers ( 21 , 22 ) and also said main rotor ( 10 ) into rotation, said rotorcraft ( 1 ) having a left aerodynamic surface ( 40 ) and a right aerodynamic surface ( 41 ) exerting transverse thrust and arranged respectively in line with said left and right propellers ( 21 , 22 ) on a stabilizer ( 15 ) located in the vicinity of a rear end (AR) of said fuselage ( 2 ), said left and right aerodynamic surfaces ( 40 , 41 ) having respective left and right flaps ( 45 , 46 ) suitable for being deflected to present respective deflection angles (α 1 , α 2 ) relative to the associated aerodynamic surfaces ( 40 , 41 ), wherein when the yaw of said rotorcraft ( 1 ) is stabilized via first and second pitches of the left and right propellers ( 21 , 22 ) respectively, regulation of the deflection angles (α 1 , α 2 ) of the left and right flaps ( 45 , 46 ) is activated only during predetermined stages of flight in order to minimize a differential pitch between the left and right propellers ( 21 , 22 ) so as to optimize the operation of said left and right propellers ( 21 , 22 ), said predetermined flight stages including the stages of low speed flight performed at an indicated air speed (IAS) of the rotorcraft less than a predetermined threshold, and stages of yaw-stabilized flight at high speed performed at an indicated air speed (IAS) of the rotorcraft above said predetermined threshold.