Hybrid cars and trucks are now a common sight on UK streets, but researchers are now taking the technology to greater heights than ever before.

 

A team from the University of Cambridge claims to have successfully built and tested the first aircraft powered by a parallel hybrid-electric propulsion system, where an electric motor and petrol engine work together to drive the propeller.

 

The scientists say the single-seater aircraft uses 30 per cent less fuel than a similar plane with a petrol engine and that it can recharge its batteries mid-flight - the first time this has been achieved.

 

During take-off and climb, when maximum power is required, the engine and motor work together to power the plane. But once the plane reaches cruising height, the electric motor can be switched into generator mode to recharge the batteries - a set of 16 large lithium-polymer cells housed in special compartments in the wings - or used in motor assist mode to minimize fuel consumption. The system uses essentially the same principle as that at work in a hybrid car.

 

Dr Paul Robertson of Cambridge's Department of Engineering, who led the project in association with Boeing, said the advent of light-weight batteries has for the first time allowed for the development of hybrid or even fully-electric aircraft.

 

Airlines have been trialling a range of technology such as alternative fuels and energy efficient equipment to reduce the emissions impact of the sector, which is responsible for between two and three per cent of global CO2 emissions, but is expected to contribute a much larger share as global trade increases and other sectors start to decarbonise. EU aviation emissions, which represent a third of the global total, have doubled since 1990 and are predicted to triple by 2050 if unchecked.

 

However, further technological advances will be needed before fuel can be done away with - if all the engines and all the fuel in a modern jetliner were to be replaced by batteries, it would have a total flying time of roughly 10 minutes.

 

Nevertheless, the researchers called the test flight "an important step forward" in developing low carbon aircraft.