Diamond Aircraft collaborated with Siemens to create the hybrid-electric twin that flew for the first time on Oct. 31 in Austria.
The highly modified DA40 was set up as a flying laboratory, fitted with a single combustion engine that delivers power to a pair of independent electric propulsion systems, each with its own battery, inverter, electric motor, and propeller, mounted on each side of a canard wing. The two motors can generate a combined 150 kilowatts (about 200 horsepower) between them for takeoff, with the nose-mounted generator providing up to 110 kilowatts.
“A distributed propulsion architecture opens entirely new possibilities for the design of highly efficient planes—and we have now proven its technical feasibility,” Siemens AG Executive Vice President of eAircraft Frank Anton said in a news release.
Diamond’s Head of Flight Test Ingmar Mayerbuch piloted the maiden flight, a 20-minute sortie that included demonstration of all three modes of operation: pure electric, with the motors drawing power only from the batteries; cruise mode, in which the generator provides all of the power; and charge mode, in which the generator charges the batteries that, in turn, power the motors. The system has 30 minutes of endurance with the generator not in use; turning it on extends endurance to five hours.
“The first flight exceeded all our expectations,” Mayerbuch said in the news release. “The combination of the hybrid powertrain and the configuration of the aircraft is just perfect. We reached 130 knots at medium power output and climbed to an altitude of 3,000 feet.”
Future test flights will determine just how efficient the hybrid propulsion system is compared to traditional aircraft, and also establish the noise footprint of the aircraft, which is capable of quieter takeoffs using battery power alone.