At the Parisian "Le Bourget" air show, Siemens, EADS and Diamond Aircraft showcased the next generation DA36 E-Star with a serial-hybrid electric drive. This drive concept enables quiet electric take-off and a considerable reduction in both fuel consumption and emissions of up to 25 per cent. The second generation aircraft has proven that this technology is suitable for commercial use.

After successful preliminary testing in 2011, joint development efforts by the companies involved have now reached a further milestone. The aircraft exhibited at the "Le Bourget" air show successfully completed a one-hour maiden flight at Wiener Neu-stadt airfield on June 1. Thanks to the innovative integrated drivetrain from Siemens, it was possible to reduce the empty weight of the motor glider by around 100 kg compared with its predecessor in 2011. This means the aircraft has a realistic capacity and range as expected from a commercial aircraft.

The propeller of the motor glider is electrically driven by a hybrid system, consisting of an Integrated Drive System from Siemens and a generator that is powered by a small Austro Engine Wankel rotary engine. The DA36 E-Star 2's drive system provides an output of 80 kW during take-off and a continuous output of 65 kW. The electric motor weighs just 13 kg. At 5 kW/kg, its specific continuous output is twice that of the first prototype and about five times greater than that of a typical industrial electric motor. The power electronics and gearbox are integrated into the electric motor and included in the weight stated. For take-off and climbing, additional energy is drawn from a battery which is recharged during cruising. This battery is provided by EADS Innovation Works (IW), the corporate research and technology network of EADS).

"The technology is scalable and will soon be making its way into small aircraft and in the future, commercial aircraft with 50 to 100 passengers, making aviation 'greener'." said Ralf-Michael Franke, CEO of Siemens Drive Technologies Division. "This milestone in development once again proves that the Siemens "Integrated Drive Systems" concept is the way of the future in drive technology. It also shows that this approach will provide higher powers coupled with increased energy efficiency in many different industries and applications."

Siemens, EADS, and Diamond Aircraft also signed a declaration of intent regarding closer cooperation on the development of hybrid electric aircraft in the margins of the Paris Air Show.