Silent flight: developing hybrid aircraft

Imagine living next to an airport where the aircraft are taking off and landing all night, but you never hear a thing?

That is the promise of hybrid aircraft, in which a small jet engine is combined with  a battery and an electric motor to drive the propellers. Such aircraft could also consume up to 50 per cent less fuel, according to Siemens.

The company, which is working with Airbus, ultimately hopes to launch 90-seater civilian hybrid-electric aircraft into the skies by 2035.

But the technology must first be proven  on smaller aircraft. To this end, Siemens has recently developed an electric motor with a weight of 50kg and a continuous power output of 260kW – enough to fly a four-seater aircraft with a take-off weight of two tonnes, when used in conjunction with a small jet engine.

”If you start purely electrically, and only switch  on the combustion engine after some time,  you will have no noise from the battery, and only a little propeller noise, which you can reduce by turning the propeller more slowly. In this way, you can make a really very quiet aircraft.