Device for control of an aerodynamic steering surface of a helicopter

An apparatus for controlling an aerodynamic steering surface of a rudder component of a helicopter (He), said helicopter (He) including a compound anti-torque system which is intended to counteract the torque induced by a main forward-movement and lifting rotor (R1) of the helicopter (He), said apparatus comprising:

• an anti-torque auxiliary rotor (R2), controllable and exerting an anti-torque lateral thrust;
• a non-rotating rudder component having a movable aerodynamic steering surface (D) with a movable position and which generates an anti-torque transverse lift;
• and
• a control system (IA, IB) that controls the speed of movement of said aerodynamic surface (D) as a function of the difference between a helicopter (He) yaw control demand and a datum demand representative of a datum control value for said auxiliary rotor (R2), as long as said difference is not zero.