Rolls-Royce has completed testing of the technology that will power the world’s fastest all-electric plane. All the technology has been tested on a full-scale replica of the plane’s core—called an ‘ionBird’—including a 500hp electric powertrain powerful enough to set world speed records and a battery with enough energy to supply 250 homes.

The plane is part of a Rolls-Royce initiative called ACCEL, short for “Accelerating the Electrification of Flight”. The ACCEL project team includes key partners YASA, the electric motor and controller manufacturer, and aviation start-up Electroflight.

The team has been developing the technology while adhering to the UK Government’s social distancing and other health guidelines; the systems will soon be integrated into Rolls-Royce’s ‘Spirit of Innovation’ plane. There is a long history of iron-birds in aviation for testing propulsion systems ahead of flight; in this case Rolls-Royce named the test airframe “ionBird”, after the zero-emission energy source propelling the aircraft.

The dedicated team have tested each and every component of the system including running the propeller up to full speed (approximately 2,400 rpm) using the most power-dense battery pack ever assembled for aircraft propulsion.

When at full power during the flight-testing phase, it will propel the aircraft to more than 300 mph setting a new world speed record for electric flight. More than 6,000 cells are packaged in the battery for maximum safety, minimum weight and full thermal protection.

Since January, engineering and test pilots have spent many hours optimizing the system and developing operating procedures for electric flight. GBs of data—generated every hour of operation—are analyzed to improve performance wherever possible.

“Rolls-Royce is committed to playing a leading role in reaching net zero carbon by 2050. The completion of ground-testing for the ACCEL project is a great achievement for the team and is another important step towards a world record attempt. This project is also helping to develop Rolls-Royce’s capabilities and ensure that we remain a leader in delivering the electrification of flight, an important part of our sustainability strategy.”—Rob Watson, Director – Rolls-Royce Electrical.

Bremont will be the official timing partner for the all-electric speed record attempt. The British luxury watch maker has also helped develop the design of the plane’s cockpit which will feature a stopwatch, while the company has machined canopy release parts at its Henley-on-Thames manufacturing facility.

The first flight is planned for later this year; the aim is to beat the current all-electric flight world record early next year. Half of the project’s funding is provided by the Aerospace Technology Institute (ATI), in partnership with the Department for Business, Energy & Industrial Strategy and Innovate UK.

The ACCEL project is the first Rolls-Royce project to use offsetting to make the whole program carbon neutral.