PM brushless motor for helicopters electric tail rotor drive system

This paper aims to present highlights and challenges related to the design of an air-cooled electric motor able to replace the traditional actuation system of the tail rotor in helicopters. The tail rotor application is presented reporting the requirements for the design of the motor and critical aspects. Hence the motor design steps and technical choices are detailed and evaluated by mean of 2D and 3D Finite Element models. The adoption of advanced materials along with an accurate mechanical design allow to obtain high power densities of the electric motor as required for aircraft application. Transient and thermal analyses in healthy mode and faulty mode operation have been used both to refine the design and verify the performances at early project steps and validate the final design.