Fraunhofer IISB Clean Aviation AMBER electric motor: 1000 hp at 94 kg for hydrogen fuel cell hybrids

Fraunhofer IISB development under the Clean Aviation programme targets aviation and hydrogen fuel cell hybrid systems

The Fraunhofer Institute for Integrated Systems and Device Technology (Fraunhofer IISB) has built a new electric motor designed for aircraft applications. The unit delivers 1000 horsepower while weighing only 94 kg, and its overall dimensions are comparable to a 12.5 kg gas cylinder. On a specific-output basis, it reaches a power density of 8 kW per kilogram-well above the figures usually seen in electric-car motors (2–4 kW/kg) and even ahead of high-end aviation motors (5–6 kW/kg).

Performance and packaging: 1000 horsepower from 94 kg

To put the headline output into perspective, the Tesla Model S Plaid relies on three motors to achieve roughly 1020 horsepower, whereas Fraunhofer IISB’s design gets close to the same result with a single motor.

The compact build is a key advantage for aviation, where both installation space and mass are tightly constrained.

Hairpin windings and direct oil-spray cooling

These figures are enabled by an unconventional layout using four three-phase hairpin windings. Instead of flexible round wire, the conductors are rigid copper bars bent into a U-shaped “hairpin” form. This approach allows more copper to be packed into the same volume, which raises current capability and power output, while also improving cooling performance and mechanical robustness.

Heat is removed using direct oil-spray cooling. By efficiently carrying heat away, this method lets the motor sustain higher power levels without overheating.

Thin NO15 steel, high speed, and a segmented architecture

Another notable change is the use of NO15 electrical steel with a thickness of just 0.15 mm-around half the thickness used in most electric motors. The thinner laminations reduce eddy currents, which in turn lowers heating and improves efficiency, particularly at high rotational speeds. The new motor is designed to run at about 21,000 rpm.

The motor is built from four independent sections. Each section has its own winding, inverter, and control system, creating inherent redundancy: if one section fails, the remaining sections can continue operating-an especially important attribute for aviation.

AMBER in Clean Aviation: hydrogen fuel cell hybrid-electric aircraft systems

Development took place under the AMBER project within the European Union’s Clean Aviation programme. The programme focuses on hybrid-electric systems using hydrogen fuel cells for regional aircraft. The stated target is to cut aviation carbon dioxide emissions by at least 30% compared with 2020 levels.

Other participants include Avio Aero with the Catalyst turboprop engine and GE Aerospace. Fraunhofer IISB, however, developed this motor fully in-house-from the initial concept through to validation in line with aviation standards.

Even with a 94 kg, 1000-horsepower result, moving from a laboratory prototype to certified aviation hardware remains a demanding step. There is also an open question over whether hydrogen fuel cells can provide reliable operation on regional routes.

Even so, in an industry where progress is often measured in decades, this motor stands out as a major engineering achievement.