Rolls-Royce took a big step forward recently on their path to stay at the forefront of aviation electrification by unveiling their new all-electric, zero-emissions plane at Gloucestershire Airport in the United Kingdom. As part of their ACCEL initiative (Accelerating the Electrification of Flight), work is accelerating as they develop a ground-breaking electrical propulsion system to enable the ACCEL program’s zero-emissions airplane to make a run for the record books with a target speed of 300-plus mph (480-plus kmph) in late Spring 2020.
The airplane is a very visible part of Rolls-Royce’s strategy to champion electrification. The project involves a host of partners including electric motor and controller manufacturer YASA and the aviation start-up Electroflight. 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. “Building the world’s fastest all-electric aircraft is nothing less than a revolutionary step change in aviation and we are delighted to unveil the ACCEL project plane,” said Rob Watson, Director of Rolls-Royce Electrical. “This is not only an important step towards the world-record attempt but will also help to develop Rolls-Royce’s capabilities and ensure that we are at the forefront of developing technology that can play a fundamental role in enabling the transition to a low carbon global economy.”
The ACCEL airplane will have the most power-dense battery pack ever assembled for an aircraft, according to Rolls-Royce, providing enough energy to fuel 250 homes or fly 200 miles (London to Paris) on a single charge. Its 6,000 cells are packaged to minimize weight and maximize thermal protection. An advanced cooling system ensures optimum performance by directly cooling cells during the high-power record runs.
For the planned speed record run, the propeller of the test airplane will be driven by three high-power-density axial electric motors. Combined, they’ll continuously deliver more than 500 horsepower for the record run. Even during the record run, the all-electric powertrain is being designed to deliver power with 90-percent energy efficiency and zero emissions. To make their efficiency point, Rolls-Royce compared the ACCEL power system to that of a Formula 1 race car, which they said tops out at close to 50-percent energy efficiency.
Rolls-Royce is taking a long-term approach to aviation electrification by partnering with many well-known companies and institutions to drive electric aircraft technology forward. “In 25 years, our business will look very different, with new customers and new competitors. We are in a unique position to influence the future of the markets we serve, and this planet we inhabit,” said Warren East, CEO, Rolls-Royce.
The ACCEL project is just one of the ways in which Rolls-Royce is developing lower-carbon power. This includes partnering with Airbus on the E-Fan X technology demonstrator project, which is an important stepping stone towards hybrid-electric commercial aircraft at the scale of today’s single-aisle family. They are also working with Widerøe, a large regional airline in Scandinavia, on a joint research program on zero-emissions aviation. The program is part of the airline’s ambition to replace and electrify its regional fleet of more than 30 airplanes by 2030.
The eFanX joint effort between Airbus and Rolls-Royce aims for a first demonstrator flight in 2020, replacing one of the four turbines on a BAE146 airplane with an electric propulsion unit, powered by a battery pack and turbine-driven generator in the main fuselage of the airplane.
Rolls-Royce is also heavily involved with Project Fresson, a multi-year program run by Cranfield Aerospace Solutions (CAeS) involving the design, manufacture and integration of a hybrid-electric propulsion system into a nine-seat Britten-Norman Islander aircraft, which is typically used on short flights such as island-hopping routes in Scotland. Conventional engines will still be available for the aircraft’s longer-range flights. Rolls-Royce is supplying the power management system as part of a wider team that includes the Denis Ferranti Group, Britten-Norman and CAeS parent Cranfield University.
“The results of this exciting electric aircraft demonstrator project can be rapidly developed into an EASA/CAA certified modification kit, enabling the UK to lead the way with the first passenger-carrying sub-regional aircraft capable of all-electric flight. This is going to accelerate our green transport revolution,” said Paul Hutton, CAeS CEO.
Project Fresson takes its name from Scottish pioneer Captain Ernest Edmund (Ted) Fresson, who returned to the UK in 1927 after flying in WWI to giving joy rides to the public, using improvised “airfields.” Those flights took on a more formal form in 1933 when Fresson set up Highland Airways, serving the Highlands and Islands of Scotland. In 1947, the airline, now part of Scottish Airways, was incorporated into the newly-nationalized British European Airways operation.