Design and Experimental Testing of a Magnetic Gear for an Electric Aircraft Drivetrain

This paper presents the magnetic, thermal and mechanical design details as well as testing result for a high mass torque density coaxial magnetic gear (MG). The MG was designed for use in an electric aircraft application and has a 12.4:1 gear ratio. The MG was designed to be competitive with a mechanical equivalent aircraft gear and had a calculated total mass torque density of 53 Nm/kg with a rated torque of 229 Nm. The proof-of-principle MG used Garolite support parts, rather than carbon fiber and due to dimensional differences, the tested MG was shown to achieve a 23.5 Nm/kg torque density. The importance of using laminated magnets and the importance of accounting for both parallel and in-plane eddy current losses within the MG is highlighted.