A plane with a parallel hybrid engine is the first ever to be able to recharge its batteries in flight and use less fuel than its petrol-only engine counterpart, it was announced.
The hybrid-electric propulsion system that powers the aircraft uses an electric motor and a petrol engine, with 30 per cent less fuel. The aircraft has been successfully designed, built and tested in the UK by researchers and engineers from the University of Cambridge in association with Boeing.
“Although hybrid cars have been available for more than a decade, what’s been holding back the development of hybrid or fully-electric aircraft until now is battery technology,” said Dr Paul Robertson of Cambridge’s Department of Engineering, who led the project.
“Until recently, they have been too heavy and didn’t have enough energy capacity. But with the advent of improved lithium-polymer batteries, similar to what you’d find in a laptop computer, hybrid aircraft – albeit at a small scale – are now starting to become viable.”
The demonstrator, based on a commercially available single-seat aircraft, uses a combination of a 4-stroke piston engine and an electric generator connected through the same drive pulley to spin the propeller.
Using the same principle as in a hybrid car, during take-off and climb – when maximum power is required – the engine and motor work together to power the plane, but as soon as cruising height is reached the electric motor can be switched into generator mode to recharge the batteries or save fuel.
“Our mission is to keep our sights on finding innovative solutions and technologies that solve our industry’s toughest challenges and continually improve environmental performance,” said Marty Bradley, Boeing’s principal investigator for the programme.
“Hybrid electric is one of several important elements of our research efforts, and we are learning more every day about the feasibility of these technologies and how they could be used in the future.”
More research is required until commercial airlines will be able to benefit from hybrid or fully-electric aircrafts. At present, if we were to replace the engines and the fuel with batteries in a plane, it would have a flying time of about ten minutes.
The testing took place at the Sywell Aerodrome, near Northampton, and included a series of ‘bounces’ along the runway as well as longer flights at 1,500ft.