Emission free flight with Hydrogen: dream or reality?

The increasing electrification of aircraft systems from actuators to “green taxi” and main electric propulsion typifies a wide field for interdisciplinary research. The German Aerospace Center in Stuttgart, mainly represented by the “energy systems integration” group at the Institute of Engineering Thermodynamics intensified its activities since 2007 in this interesting research field.

Main topics of the research are the development and optimization of high efficient power generators and complete electrical power trains based on hydrogen fuel cells, batteries, efficient voltage converters and high torque electrical motors.

Mainly for the general aviation, an adapted fuel cell system can be used as a power generator unit for the main aircraft propulsion during flight. Therefore the lightweight and the maximized efficiency coupled with an high redundancy and reliability play a major role. Started in 2009 with a “one seater” DLR‐H2 all electric fuel cell driven aircraft, todays development shows the near term feasibility of a “four seater” ‐ “HY4” and the perspective beyond.

This oral presentation will give an overview on the feasibility of a hydrogen fuel cell system and hybrid system as power source for aircraft propulsion. The further development of this path includes the system architecture optimization regarding reliability and redundancy. An redundant system architecture will be presented. With this architecture one of the four systems can be removed, maintained and reintroduced during max load current, so the capability of the plane to maintain altitude is not affected. The main implications of such specialized energy system architectures will be discussed during the presentation.