Siemens, EADS test 2nd generation hybrid drive for airplanes

June 18, 2013 // By Christoph Hammerschmidt
At the Paris Air Show, Siemens, EADS and Diamond Aircraft show the second generation of an airplane equipped with a serial hybrid electric drive. The powertrain of the motor glider has been redesigned to reduce the weight by 100 kg. Siemens believes that this second generation engine proves the commercial fitness of the technology.

With reduced weight for the hybrid power train including batteries, the DA36 E-Star 2 motor glider offers a realistic load capacity and a range users can expect from a commercial plane.

The propeller is driven by a hybrid system which embraces an integrated electric power train provided by Siemens and a generator which is powered by a small Wankel engine - similar to a range extender used in hybrid vehicles. The electric motor features a weight of only 13 kg yet offers a continuous power of 65 kW and a take-off power of 80 kW. The specific continuous output has been doubled compared to the first prototype; compared to an average industrial electric motor it is five times higher. The unit includes a mechanical transmission and a power electronics unit. During take-off and ascent, the motor extracts additional power from the battery which will be recharged during cruise flight.

According to Siemens, the technology scales well and could soon be utilized in small airplanes; in the more distant future it also could drive larger passenger airplanes designed to transport 50 to 100 passengers, believes Ralf-Michael Franke, CEO of Siemens' Drive Technologies.

During the Paris Air Show, Siemens, EADS and Diamond Aircraft also signed a declaration of intent for the joint development of electrically-driven planes. Such aircraft would produce up to 25% less emissions and at the same time also uses 25% less fuel compared to the most efficient aircraft propulsion technologies, Siemens said.