Method of optimizing the noise generated in flight by a rotorcraft

A system for optimizing noise generated by a hybrid power plant of a rotorcraft during a flight phase, the hybrid power plant being provided with at least one engine and with at least one electric machine, the system comprising:

• a controller configured to determine a required power to be delivered by the hybrid power plant for the flight phase, and to distribute the required power between the engine(s) and the electric machine(s) as a function of a target noise level, the required power, and a model for a noise generated by the engine(s) depending on an operating parameter of the engine(s);
• wherein to distribute the required power between the engine(s) and the electric machine(s) the controller is further configured to control the electric machine(s) to progressively increase a supplementary power delivered by the electric machine(s) and control the engine(s) to reduce a main power delivered by the engine(s) so that the hybrid power plant delivers the required power;
• and
• the model for the noise generated by the engine(s) includes a first increase zone in which the model models the noise generated by the engine(s) increasing as the operating parameter increases followed by a decrease zone in which the model models the noise generated by the engine(s) decreasing as the operating parameter further increases followed by a second increase zone in which the model models the noise generated by the engine(s) increasing as the operating parameter further increases, and while the main power delivered by the engine(s) leads to the engine(s) operating in the decrease zone, the controller is further configured to control the engine(s) to increase the operating parameter of the engine(s) and thereby increase the main power delivered by the engine(s) and cause the engine(s) to cease operating in the decrease zone and to instead operate in the second increase zone, and control the electric machine(s) to reduce the supplementary power delivered by the electric machine(s) so that the hybrid power plant delivers the required power.

A rotorcraft comprising:

• a hybrid power plant provided with at least one engine and with at least one electric machine;
• and
• a system for optimizing noise generated by the hybrid power plant during a flight phase, the system including a controller configured to determine a required power to be delivered by the hybrid power plant for the flight phase, and to distribute the required power between the engine(s) and the electric machine(s) as a function of a target noise level, the required power, and a model for a noise generated by the engine(s) depending on an operating parameter of the engine(s);
• and
• wherein to distribute the required power between the engine(s) and the electric machine(s) the controller is further configured to control the electric machine(s) to progressively increase a supplementary power delivered by the electric machine(s) and control the engine(s) to reduce a main power delivered by the engine(s) so that the hybrid power plant delivers the required power;
• and
• the model for the noise generated by the engine(s) includes a first increase zone in which the model models the noise generated by the engine(s) increasing as the operating parameter increases followed by a decrease zone in which the model models the noise generated by the engine(s) decreasing as the operating parameter further increases followed by a second increase zone in which the model models the noise generated by the engine(s) increasing as the operating parameter further increases, and while the main power delivered by the engine(s) leads to the engine(s) operating in the decrease zone, the controller is further configured to control the engine(s) to increase the operating parameter of the engine(s) and thereby increase the main power delivered by the engine(s) and cause the engine(s) to cease operating in the decrease zone and to instead operate in the second increase zone, and control the electric machine(s) to reduce the supplementary power delivered by the electric machine(s) so that the hybrid power plant delivers the required power.