Patent ID: 7223071
Filing Date: 2007-05-29
Classification: B64C

Abstract:
1. A device enabling the collective pitch of the blades of the main rotor of a single-engined rotorcraft to be reduced automatically in the event of an engine failure, comprising: an actuator means for increasing said collective pitch of the blades when said engine is operating above a predefined threshold and for immediately changing a pitch of a swash plate to a pilot pitch to decrease said collective pitch of the blades as said engine passes below said predefined threshold, said predefined threshold corresponding to said engine operating at a low level of power, said low power level enabling the main rotor speed to be greater than an authorized minimum speed, said actuator means being controlled by pressure of a gas taken from said engine; a connection that connects said actuator means to the swash plate; and a dissymmetric filter unit that regulates the pressure of said gas upstream from said actuator means.