Fraunhofer Develops High‑Power Electric Aircraft Motor for Project AMBER

April 17, 2026

Fraunhofer researchers developed this electric motor with 12 phases that reaches a maximum speed of 21,000 rpm and delivers a rated power of 750 kW for hybrid-electric aircraft applications. (Image: Fraunhofer Institute for Integrated Systems and Device Technology)

Fraunhofer researchers have unveiled a 750‑kW class electric aircraft motor designed to meet the demanding power density, reliability, and thermal requirements of hybrid‑electric regional aviation. The motor represents a key hardware contribution to Project AMBER, a flagship initiative under the European Union’s Clean Aviation program aimed at validating megawatt‑class hybrid‑electric propulsion architectures for next‑generation regional aircraft.

Motor Architecture and Key Engineering Features

The newly developed machine is a permanent‑magnet traction motor delivering up to 750 kW (≈1,000 hp) while weighing approximately 94 kg, corresponding to a power density of about 8 kW/kg — a level typically associated with small turboprop engines rather than electric machines. This performance is enabled by a combination of advanced electromagnetic, mechanical, and thermal design choices.

A central design feature is the use of rectangular hairpin windings rather than conventional round‑wire coils. The 4×3‑phase distributed hairpin stator allows higher copper fill factors and current density while improving thermal contact with the stator core. The configuration also supports fault tolerance: the motor is divided into four electrically independent sections, each capable of continuing operation if another section fails — an important consideration for aviation certification and dispatch reliability, according to a Fraunhofer LinkedIn post about the new motor.

To manage heat at high power and rotational speeds, the motor employs direct oil‑spray cooling, enabling effective removal of losses from the windings and stator. Researchers also selected ultra‑thin NO15 electrical steel laminations (0.15 mm) to reduce eddy current losses, particularly important at the motor’s rated speed of roughly 21,000 rpm.

The Clean Aviation AMBER Project

The electric motor was developed as part of AMBER (InnovAtive deMonstrator for hyBrid‑Electric Regional application), a Clean Aviation project targeting a ~2‑MW hydrogen fuel‑cell‑based hybrid‑electric propulsion system for regional turboprop aircraft. AMBER’s architecture is a parallel hybrid, pairing a conventional turboprop — such as Avio Aero’s Catalyst‑class engine — with an electric motor/generator, fuel cells, and associated power electronics.

Within this framework, Fraunhofer’s motor functions as a core propulsion and energy‑conversion element, supporting electrically assisted takeoff, climb, and optimized cruise operation. By enabling higher degrees of hybridization, the AMBER consortium aims to achieve at least 30 percent CO₂ reduction at entry into service compared with 2020‑era regional aircraft, with further lifecycle gains possible when paired with sustainable aviation fuels or hydrogen.

Toward Product‑Representative Hybrid Propulsion

Beyond headline power density, Fraunhofer emphasizes that the motor was developed end‑to‑end in accordance with aerospace standards, from concept definition and CAD design through manufacturing, assembly, and validation. This approach aligns with AMBER’s broader goal of maturing technologies to TRL 4–5 by the mid‑2020s, reducing risk for future demonstrators and potential commercial adoption.

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