Electric technology takes to the skies again

The Bye Aerospace eFlyer 2 prototype and the technology demonstrator CityAirbus have resumed flight tests in the last ten days. Both aircraft are powered by electrical propulsion systems we have developed and they have been flying in short sessions to demonstrate the technology.

The Bye Aerospace 2-seater eFlyer 2 aims to be the first FAA-certified, practical, all-electric aeroplane in the flight training and general aviation markets. The aircraft is being designed and developed by Bye Aerospace in Colorado, USA. We provide the Electric Propulsion Unit (EPU), consisting of a 70kW electric motor, the associated power electronics inverter and  corresponding motor controller. The system, which was developed by the Rolls-Royce Electrical team based in Budapest, Hungary, started test flights in early 2019.

Propellor testing

Bye Aerospace has been testing various propellers and propeller settings in order to optimise various performance elements of the aircraft such as climb and cruise, among others. 

Such flight tests are a key enabler when it comes to learning about platform level system integration and overall platform performance tuning prior to the start of the formal certification flight tests in 2021.

“It is so rewarding to see the eFlyer 2 and the CityAirbus demonstrators resume flying powered by our propulsion systems. These tests are equally important for our customers – the airframers – and us and are an important step in the journey to certification and commercial launch.”

Mike Mekhiche
Programme Director of Rolls-Royce Electrical

Bye Aerospace eFlyer 2 Technology Demonstrator

Rolls-Royce plans to launch its first certified electric propulsion unit for the small propeller aircraft market by 2023.

The eFlyer 2 uses no fossil fuels and as a result will make pilot training sessions very cost competitive as well as emissions-free. Due to its low operational costs, the aircraft will be able to help train future pilots efficiently, potentially making it an important element in sustaining the future aviation industry.

It also continues to be an exciting time in the emerging and ground-breaking Electric Vertical Take-Off and Landing aircraft, or eVTOL market with many start-ups and established players competing to be the first to commercially introduce the air taxis of the future. Rolls-Royce is at the forefront by developing the propulsion system for the CityAirbus demonstrator, in collaboration with Airbus. The all-electric octocopter is designed to carry up to four passengers at a maximum speed of 75 miles per hour.

Footage courtesy of Airbus

For acoustic control and a quieter flight, the eight propellers are rotated at a relatively low speed of less than 1000 rpm.

A Rolls-Royce Electrical team in Munich, Germany has developed an electric propulsor comprising a 200kW electric motor and associated power electronics, controller and the power protection and distribution system to generate, distribute and manage the required high electro-mechanical torque. This is then, converted into tremendous thrust via the platform propellers at low speed.

Mike added: “Both these projects are an important demonstration that Rolls-Royce can provide the innovative and sustainable power and propulsion technology needed for the different sized aircraft of the future. This technology is also a key enabler in the highly contested urban air mobility market and several other segments of the aerospace market.”

The CityAirbus’ first untethered flight was in December 2019 and flights have now taken place as part of an extensive new testing campaign including altitude testing. The team are aiming to reach new heights in the coming weeks with technology that could help shape future travel within cities.

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