UK company Magnomatics announced today that it has designed a lightweight, air-cooled propulsion motor suitable for the rapidly growing Urban Air Mobility sector, specifically for eVTOL aircraft. The 86kW motor has a torque density of 30Nm/kg.
“NASA has identified magnetic gears as being a potential technology for electric aircraft,” said a company press release. “In 2018 they embarked on a two and half year programme described in their paper Magnetic Gearing Research for Electrified Aircraft Propulsion. Their original focus was on pure magnetic gears but in the 2020 paper Outer Stator Magnetically Geared Motors for Urban Air Mobility Vehicles they concluded that the concentric combination of a magnetic gear and a permanent magnet motor would be ideal for an eVTOL UAM aircraft.”
Magnomatics spun out of the University of Sheffield in 2006 to commercialise technology based on magnetic gears. Among its patented products is the Pseudo Direct Drive (PDD®), which is an Outer Stator Magnetically Geared Motor (OMSGM). In 2019 Magnomatics built and tested the largest PDD to date, with a 200,000Nm rating. This was subsequently tested at the Offshore Renewable Energy Catapult at Blyth in the UK. Based on the results a large global engineering company is now evaluating the PDD technology for a number of sectors.
“The UAM motor designed is based upon PDD® technology, identified by NASA as being “roughly two times greater than the specific torque expected of a direct drive electric motor for the same application,” said the company.
The company also reports that it has recently started a NATEP (National Aerospace Technology Exploitation Programme) grant-funded project to investigate further light-weighting of the motor and is collaborating with Carbon ThreeSixty to see how composite materials can be used to further reduce the mass and potentially enhance performance to provide an increase in torque density to greater than 30Nm/kg. The company says the motor will be manufactured and tested to meet DO-160G specifications.
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