Heavyweight companies' plan for hybrid plane 'a stepping stone to electric flight'

Heavyweight plans for hybrid-powered test flights are a “stepping stone” towards fully electric planes, an expert has said – but, he warned, we may still have to wait 50 years.

This week, Airbus, Rolls-Royce and Siemens announced a new partnership aimed at flying a plane with an electric motor in 2020. The companies hope to replace one of four gas turbine engines on a BAe 146 testbed aircraft with a 2MW motor, potentially replacing another one after successful trials.

The project leaders hope to examine the effects of challenges such as temperature changes, altitude, thrust management and other dynamic effects on electric systems, with the aim of maturing the technology, performance, safety and reliability of hybrid flight.

The companies are committed to the European Commission’s Flightpath 2050 Vision for Aviation, including a CO₂ emissions cut of 75%, NOx cut of 90% and noise cut of 65%, and they hope hybrid planes could lead a path towards the reductions.

Hybrid flight is “definitely going to be the medium-term solution of the electrification of aerospace,” said Steve Wright, avionics lecturer at the University of the West of England in Bristol. “It’s a stepping stone, but nothing moves fast in aerospace,” he added, speaking to Professional Engineering. “Aerospace is a notoriously cautious and conservative industry… so even this test stepping stone is going to be a few decades long.”

The current problem with widespread electrification for large aircraft is endurance, he added. Although state-of-the art electric motors can put out a lot of power, the best batteries’ energy storage pales in comparison to aviation fuel, which contains approximately 40MJ/kg, compared to 1MJ/kg.

Making electric flight a reality

Any commercial hybrid planes are expected to be small two-seat, then bigger six-seat jets. The consortium reportedly hopes the project, known as E-Fan X, will lead to commercial regional passenger jets by the 2030s.

“The E-Fan X is an important next step in our goal of making electric flight a reality in the foreseeable future,” said Paul Eremenko, Airbus chief technology officer. “The lessons we learned from a long history of electric flight demonstrators will pave the way to a hybrid single-aisle commercial aircraft that is safe, efficient and cost-effective.”

The project, combined with previous electric flight groundwork, will “revolutionise flight and welcome in the third generation of aviation,” claimed Paul Stein, Rolls-Royce chief technology officer. “This is an exciting time for us as this technological advancement will result in Rolls-Royce creating the world’s most powerful flying generator.”

Content published by Professional Engineering does not necessarily reflect the views of the Institution of Mechanical Engineers.