Schaeffler Technologies AG & Co. KG
eMotoren Aviation Luftfahrt


Aviation applications can be readily adapted from motor sports applications, since the requirements are practically identical. High power density makes the vision of electric flight with a large payload possible.

Aviation - Compact Dynamics

Power density (kW/kg) of the e-motor, power electronics, and housing in 2016 was still around 8 kW/kg during continuous output, and approx. 11 kW/kg at maximum power (2 minutes); thus, the technical development in the coming years will represent a considerable increase in power density.

Potential of improvement

Magnet technology:

Magnet technology
Magnet technology
Magnet topology

Internal or external rotors

In contrast to internal rotors, the air gap in external rotor drives can be kept very small, since the rotor sleeve has a strong influence on the mechanical air gap. The air gap between the rotor and stator is of great importance for the surface thrust of an electrical machine.

Innenläufer mit Bandage - Aussenläufer ohne Bandage

Surface magnets with soft magnetic yoke vs. Halbach array

magnet topology
soft magnetic yoke
magnet topology
Halbach Array

Greater power density through

modified rotor geometry

Magnet topology

Smaller pole pitches

A smaller pole pitch allows for

  • smaller coil heads
  • improved cooling for the winding
  • less magnetic material and iron
  • reduced weight

optimized design of power electronics

A special power electronics design ensures high pole change frequencies, placing greater demands on the machine controls.

The next generation of SiC-based power modules enables

  • switching frequencies of up to 60 kHz
  • Sinusoidal currents with reduced harmonic losses
  • improved efficiency

Greater integration density

Integration of motor and power electronics in one housing creates

  • joint cooling circuits
  • no need for the phase cable
  • reduced weight

These optimizations in aviation applications already implemented by Compact Dynamics have led to significant improvement in power density:

Aviation - System integration

We believe there is further potential for optimization in

  • enhanced material properties
  • new cooling technologies
  • optimization of drive systems
eMotor power densities
power densities

Power densities of up to 14 kW/kg and more during continuous output, and considerably above 18 kW/kg at peak performance, are certainly feasible for applications in electrical aviation, as we continue on the development path
that is set out.

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Aviation applications


Compact Dynamics is exclusive FIA supplier for the hybrid system from 2022 to 2024

The WRC Rally Classic - the Rally Portugal - will be held around Porto from 9 to 12 May 2024. A well-known and popular route with fast and technically demanding gravel roads, initially soft and sandy, but on the second pass they can become rocky and rutted. There are often tricky bends to master behind hilltops and sometimes very high temperatures in the early Portuguese summer.

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Compact Dynamics supports FIA and competitors with 3 trackside support engineers

More Information

Compact Dynamics GmbH
Moosstraße 9
82319 Starnberg
Phone +49 8151 9043-0
Fax +49 8151 9043-20

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Compact Dynamics GmbH:  Technology examples » Aviation