Researchers at Siemens (www.siemens.co.uk) in Germany have designed a new type of electric motor that could help to make electric-powered passenger aircraft a reality.

The motor weighs just 50kg but delivers a continuous output of about 260kW — five-times more than comparable drive systems, and sufficient to allow aircraft with a take-off weight of up to two tonnes use of electric drives for the first time.

Electric motors of comparable strength that are used in industrial applications typically deliver less than 1kW per kg, while the performance of drive systems used in electric vehicles is about 2kW per kg.

Siemens claims that its 5kW per kg was achieved by using advanced simulation techniques and reducing the weight of every component in the system. Furthermore, because the motor delivers its performance at rotational speeds of just 2,500rev/min, it can drive a propeller directly (without the use of a transmission system).

Frank Anton, head of eAircraft at Siemens Corporate Technology, said: “This innovation will make it possible to build series hybrid-electric aircraft with four or more seats. We are convinced that the use of hybrid-electric drives in regional airliners with 50-100 passengers is a real medium-term possibility.”

Siemens is not alone in pursuing the goal of electric flight; Airbus has also made big strides with electric propulsion technology.

Its two-seater E-Fan aircraft made its first public flight last year, and the company has a long-term vision of developing a 90-seater electric passenger plane.