Electric aircraft motor achieves 1,000 hp output with mere 207 pound weight
Fraunhofer Institute for Integrated Systems and Device Technology (IISB) has developed a new lightweight, powerful, and efficient electric aircraft motor. Able to pump out 1,000 hp (750 kW), this new motor could open the door to reliable hybrid-electric regional aircraft fleets.
The new motor weighs as little as 207 pounds (94 kg), which is important for aviation as every added pound/kg reduces range and increases fuel consumption. Any effort to shed weight where possible is key to an aircraft’s power-to-weight ratio.
To this end, the new motor is able to achieve a ratio of 8 kW per kilogram, which is extremely good for aviation electric motors. To put that into perspective, a typical EV motor is usually capable of between 2-4 kW/kg, with more advanced aviation motors between 5-6 kW/kg.
At 8 kW/kg, this new motor looks very impressive indeed. Its recorded output of 1,000 hp is also impressive, as that is roughly equivalent to a small turboprop aircraft engine.
That would be enough to power a regional aircraft, and is the same ballpark as engines on small commuter planes, give or take. However, this new engine is smaller, lighter, and entirely electrically powered, which is its unique selling point.
Powerful, lightweight, and robust EV motor
This was achieved, the Fraunhofer explains, using something called hairpin windings instead of more traditional methods like copper wire. By using 4×3-phase hairpin windings, the new motor can pack more copper into the same space.
This means it can produce a higher current, leading to more power. It also provides better cooling and is mechanically stronger. The motor is also direct oil spray cooled, which is another major innovation.
So, instead of relying on air cooling, the use of oil helps remove heat faster, allowing higher output without overheating. This, in turn, helps make the motor smaller, which is great for applications like aircraft.
Another major innovation is the motor’s use of ultra-thin NO15 (0.15 mm) steel. That is around half the thickness that most electrical motors use. This is critical as the thinner the metal used, the fewer eddy currents are produced.
That, in turn, produces less heat and, ultimately, makes the motor far more efficient. This is especially important at higher speeds, with the new motor able to produce around 21,000 rpm.
Another interesting part of the motor is its reported fault tolerance. According to the team, the motor is comprised of no less than four independent sections.
Part of the EU’s Project AMBER
With each section having its own winding, inverter, and control systems, this means that if one fails (for whatever reason), the motor is still able to run. In the air, this is critical, as it means the aircraft won’t completely lose an engine should something go wrong in one section.
The new motor, Fraunhofer explains, has been developed as part of the European Union’s goal for “clean aviation” called Project AMBER. This project aims to promote technologies like hydrogen fuel cells and hybrid turbine aircraft with the ultimate hope of reducing carbon dioxide emissions from aviation by 30% or more.
The project envisages a hydrogen fuel cell to provide electricity, which, in turn, is used to drive electrical motors at the prop. Such aircraft could also make use of turboprop engines to assist when required.
This should, the project hopes, lead to cleaner, quieter, and far more fuel-efficient aircraft.
