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ACCEL – Joint project from YASA, Rolls-Royce & Electroflight

A joint team of Rolls-Royce, YASA and Electroflight received funding from the UK Government to carry out research aimed at accelerating the adoption of all-electric propulsion in aviation.

Funded through the UK’s Aerospace Technology Institute, Rolls-Royce is leading a research project known as Accelerating the Electrification of Flight (ACCEL) to explore the use of a high power electrical system in a demonstrator aircraft.

The project aims to flight test the system to gain a detailed understanding of the potential for all-electric flight. Rolls-Royce will be supported by Electroflight Ltd (UK), specialists in high performance electric powertrains including energy storage systems, and YASA (UK), a manufacturer of high-power, light weight electric motors and controllers used in automotive, aerospace and industrial applications.

Marion Boric on Aviation Pros reports that the project’s specific aims are to set new records for time to climb for an electrically powered aircraft, and highest voltage and highest power density achieved for an aircraft battery system.

Rob Watson, Director of Electrical, Rolls-Royce said: “The increased use of electrical systems is an inescapable trend in our markets and championing electrification is a core part of our long-term strategy at Rolls-Royce.”

Chris Harris, CEO, YASA said: “Thanks to our innovative axial-flux design, YASA can deliver the smallest, lightest electric motors for a given power and torque – opening up new and exciting opportunities for electrification in aerospace.”


Roger Targett, Managing Director, Electroflight said they are drawing on expertise from the automotive and motorsport sectors including Jaguar Land Rover, McLaren Automotive, Williams F1 team, and the Bloodhound SSC project to accelerate the evolution of electric aircraft.

ElectroFlight already have an all-electric racing aircraft, the P1E (left), in mock-up, as well as plans for an all-electric aircraft racing series along the lines of the Red Bull Air Races. The P1E is a contra-rotating twin prop, twin motor, low-wing monoplane racing design, powered by YASA 750 motors – how its design integrates with the ACCEL programme remains to be seen.

Electroflight has selected Zuken’s E3.series electrical and fluid engineering solution to design, build, test and commercialise the all-electric aircraft within a 24-month timeframe. Stjohn Youngman, Electroflight’s Programme Manager, comments: “E3.series was selected because of its ease-of-use, flexibility, and output capability for all data needed to manufacture wiring harnesses, including bills of materials.”

E3.series is widely used within the motorsport industry, where it helps meet racing deadlines. Electroflight plans to take advantage of E3.series’ aerospace/motorsport synergies as it will use System 25 mil-spec motorsport connectors and harness construction techniques on the ACCEL aircraft. To keep the weight of the aircraft down, Electroflight will be trying to keep cable runs as short as possible – through the smart placement of sources, switches and loads. In this respect, E3.series’ ability to integrate well with leading MCAD tools was another reason for selection.

This project feels like it could go interesting places. YASA and Roll-Royce all have track records of delivering, and Electroflight has a team with plenty of practical experience, so there’s no reason this project shouldn’t be successful.

There is interest in this type of competitive aircraft, and the concept of an all-electric race series can only boost research and development and raise the technology’s profile, as both the Red Bull Air Races and Formula E have done for aircraft in general and electric racing / cars respectively.

Beyond that, the general aviation market is an obvious target for electric aircraft products.

It’s also yet another electrification project for Roll-Royce (along with EFan, Volante Vision, EVTOL Concept taxi), showing their intentions to be a major player in the future of electric aircraft. Most of these projects could produce or feed experience into future marketable products, but more importantly, they show a company interested in research and development outside their traditional areas of combustion engines.