The future of battery-powered flight got a major boost after Siemens researchers in Germany announced they have achieved a technological breakthrough with a new type of electric engine for aircraft that is five times more powerful than previous generation motors.
Weighing in at a little over 100 pounds, the new motor delivers a continuous output of 260 kilowatts (the gasoline-piston engine equivalent of about 350 hp), compared with just 60 kw for an electric engine tested in flight by Siemens, Airbus and Diamond Aircraft last year.
Thanks to its much improved power-to-weight ratio, bigger airplanes with maximum takeoff weights of up to 4,000 pounds will be able to use electric drives for the first time, the Siemens researchers say.
To develop the electric engine, Siemens studied every component of previous motors and optimized each to their technological limits. New simulation techniques and lightweight construction, the company said, enabled the drive system to achieve a unique weight-to-performance ratio of 5 kilowatts per kilogram. Comparable motors used in industrial applications deliver less than 1 kw per kg, while drive systems used in electric cars offer about 2 kw per kg.
And because the new motor delivers its performance at rotational speeds of just 2,500 rpm, it can drive propellers directly without requiring energy-sapping reduction gears.
“This innovation will make it possible to build series hybrid-electric aircraft with four or more seats,” said Frank Anton, head of eAircraft at Siemens Corporate Technology, the company’s central research unit.
The electric engine is scheduled to begin flight-testing before the end of the year. In the next step, researchers say they will attempt to boost output further. There was no word on the expected flight endurance of aircraft powered by the new motor, but Airbus researchers have been targeting the four-hour mark with reserves.
“We’re convinced that the use of hybrid-electric drives in regional airliners with 50 to 100 passengers is a real medium-term possibility,” Anton said.
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