Outer Rotor Design of a High-Power Density Aviation Motor

Raytheon Technologies Research Center (RTRC) is currently developing a high power-density (12kW/kg) motor under the ARPA-E ASCEND program. A key element of the unique motor design is the outer rotor that utilizes pre-stressed magnets wrapped between a very thin inner sleeve and a metallic-composite hybrid outer sleeve. In this paper, we first present the trades and thermomechanical analysis leading to the outer rotor design which meets performance requirements and safety margin in the desired operating space. Further we discuss challenges associated with manufacturing the outer rotor and a unique method used to fabricate a prototype. Lastly, we discuss the nondestructive evaluation (NDE) conducted to understand the prototyping output. The issues revealed by the evaluation will be addressed in future prototyping