MIT Unveils a Megawatt Motor for Electric Aircraft

By Edd Gent

Aviation aims to slash some of its substantial carbon emissions by electrifying aircraft, but the industry’s stringent weight restrictions make this difficult. Building electric motors that match the power-to-weight ratios of jet engines has proven especially challenging, so most efforts have been restricted to smaller aircraft. A new compact lightweight design for a megawatt-scale motor unveiled by researchers at MIT could open the door to electrifying much larger aircraft.

While the automotive sector is undergoing a transition from fossil fuels to battery power, doing the same in aviation is much harder. The energy density of modern batteries is still far too low to power aircraft for substantial distances, which is why companies like Eviation are focused on short intercity hops and a host of EVTOL companies are aiming to disrupt the daily commute.

“There is no silver bullet when it comes to achieving the required paradigm shift in specific power. Many things together make the design possible, and the devil is in the details.”

Zoltán spakovszky

Batteries may get most of the attention, but they’re not the only place where weight is a problem—electrifying the motors has also been a challenge. Electric motors create thrust by passing current through large amounts of copper wiring and steel to create magnetic fields that can turn a rotor. These materials are inherently heavy, says Zoltán Spakovszky, a professor of aeronautics at MIT, which makes it difficult to build electric motors with a high power-to-weight ratio, also known as specific power. That’s because making motors more powerful means adding a lot more metal.