US Patent 9174728 Electrical powered tail rotor of a helicopter

The invention is related to an electrical powered tail rotor (1) of a helicopter comprising a housing (2) around the tail rotor (1), and at least one permanent magnet energized synchronous motor with a stator (6, 7) with an increased number of poles (9). Said at least one synchronous motor is integrated as a torus (8) around an opening of the housing (2) encompassing the tail rotor (1). Blades (4) of the tail rotor (1) are fixed to at least one rotating component (10, 11) of said at least one synchronous motor. Supply means provide for electric energy to said at least one synchronous motor. Blade pitch control means are provided at the torus (8).