Abstract: The present invention relates to an electric machine (1) that includes a stator (10) and a rotor (20), with the said stator (10) being equipped with at least one annular exciter unit (11) that includes a coil (12) and at least two annular yokes (13a, 13b), with the said rotor being equipped with a structure (21) and at least one annular receiver unit (22). Each receiver unit (22) includes at least two rows (24) of magnets (23). Two sides (131, 132) of each yoke (13) include teeth (14) distributed angularly in a regular manner, and the said teeth (14) of the two adjacent yokes (13) fit onto a face (121) of the said exciter unit (11), alternately forming north poles and south poles.

Abstract: A method of assisting a pilot of a single-engined rotary wing aircraft (1) during a stage of flight in autorotation, said aircraft (1) including a hybrid power plant having an engine (13), an electric machine (12), and a main gearbox (11). Said aircraft (1) also includes electrical energy storage means (14) and a main rotor (2) mechanically connected to said hybrid power plant (5). According to said method, while in flight, the operation of said engine (13) is monitored in order to detect a failure thereof, in particular by monitoring for a drop of power on said main rotor (2), and then in the event of a failure of said engine (13) being detected, said electric machine (12) is controlled to deliver auxiliary power We to said main rotor (2), thereby enabling the pilot of said aircraft (1) to be assisted in maneuvering said aircraft (1) during said stage of flight in autorotation following said failure.