Abstract: The present invention relates to a control method in case of engine failure of a hybrid helicopter having a power plant connected to at least one lift rotor and to at least one propeller, said lift rotor having a plurality of first blades and said at least one propeller having a plurality of second blades. The method comprises the following steps: (i) measuring a forward speed of the hybrid helicopter, (ii) on condition that said forward speed is greater than a first speed threshold and that each engine has failed, automatically implementing a first emergency piloting mode comprising a step for automatic reduction by an automatic piloting system of a pitch of said second blades toward an objective pitch making said at least one propeller produce a motive power which is transmitted to the lift rotor.

Abstract: A method for optimizing the operation of at least one first propeller and of at least one second propeller of a hybrid helicopter. The method comprises the following step during a control phase: deflection, with an autopilot system, of at least one aerodynamic stabilizer member into a setpoint position having, with respect to a reference position, a target deflection angle that is a function of a setpoint deflection angle, the setpoint deflection angle being calculated by the autopilot system in order to compensate for a torque exerted by the lift rotor at zero sideslip.

Abstract: A method for controlling a hybrid helicopter having at least one lifting rotor, at least one forward-movement propeller and an empennage provided with at least one moveable empennage surface. The method includes the following steps: using a main sensor to determine a current value of a rotor parameter conditioning a current power drawn by the lifting rotor, using an estimator to determine a current setpoint of the rotor parameter, adjusting a position of the moveable empennage surface using a deflection controller as a function of the current value and of current setpoint.

Abstract: A method for controlling a hybrid helicopter having at least one lifting rotor, at least one forward-movement propeller and an empennage provided with at least one moveable empennage surface. The method includes the following steps: using a main sensor to determine a current value of a rotor parameter conditioning a current power drawn by the lifting rotor, using an estimator to determine a current setpoint of the rotor parameter, adjusting a position of the moveable empennage surface using a deflection controller as a function of the current value and of current setpoint.

Abstract: A method for optimizing the operation of at least one first propeller and of at least one second propeller of a hybrid helicopter. The method comprises the following step during a control phase: deflection, with an autopilot system, of at least one aerodynamic stabilizer member into a setpoint position having, with respect to a reference position, a target deflection angle that is a function of a setpoint deflection angle, the setpoint deflection angle being calculated by the autopilot system in order to compensate for a torque exerted by the lift rotor at zero sideslip.

Abstract: The present invention relates to a control method in case of engine failure of a hybrid helicopter having a power plant connected to at least one lift rotor and to at least one propeller, said lift rotor having a plurality of first blades and said at least one propeller having a plurality of second blades. The method comprises the following steps: (i) measuring a forward speed of the hybrid helicopter, (ii) on condition that said forward speed is greater than a first speed threshold and that each engine has failed, automatically implementing a first emergency piloting mode comprising a step for automatic reduction by an automatic piloting system of a pitch of said second blades toward an objective pitch making said at least one propeller produce a motive power which is transmitted to the lift rotor.