Method and device for synchrophasing the propellers of an aircraft with several propulsion units

A device for constant-speed synchrophasing of the propellers of an aircraft having several propulsion units and an aircraft central control unit, each propulsion unit including an electronic control circuit connected to an aircraft communications network and means of varying the propeller rotational speed, wherein:

• each electronic control circuit of a propulsion unit includes:
• an internal clock to deliver a clock signal at a predetermined frequency representing a propeller rotational speed corresponding to a constant speed,
• a sensor to produce a signal representing the propeller rotational speed, and
• a circuit to measure the offset between the clock signal and the signal produced by the sensor,
• the electronic control circuit of a predetermined “master” propulsion unit additionally including a circuit enabling the transmission via the aircraft communications network of propeller phase reference information representing the offset measured by the control circuit of the “master” propulsion unit, and
• the or each of the electronic control circuit(s) of the or each of the other “slave” propulsion unit(s) additionally including a circuit to compare the difference between the offset measured by this control circuit and the propeller phase reference information received via the aircraft communication circuit with a determined propeller phase displacement value, and to produce, where necessary, a signal controlling the means of varying the propeller rotational speed depending on the result of the comparison, and in that:
• synchronisation circuits to synchronise the clocks by communicating via the aircraft communications network in response to the receipt of a clock realignment control signal transmitted by the central control unit of the aircraft.