Rolls-Royce has completed successful ground tests of a hybrid system using its M250 gas turbine. The tests pave the way for experimental flights on aircraft in 2021.

Rolls-Royce successfully tested the hybrid version of the M250 gas turbine in a ground demonstration setting in three operating modes: Series Hybrid, Parallel Hybrid and Turbo-Electric.

The M250 hybrid will be used as a propulsion plant with power ranging from 500kW to 1MW and Rolls-Royce says it has the potential to “transform aviation power”.


The system will be used across a range of transport platforms to enable distributed electric propulsion, including eVTOLs (electric vertical take-off and landing vehicles – in this case, hybrid electric), general aviation aircraft and hybrid helicopters.

Dr Mike Mekhiche, Deputy Director, Rolls-Royce Electrical said: “Rolls-Royce has always been a pioneer in aviation and one of the key elements of our strategy is to champion electrification across all our businesses. The successful testing of the hybrid M250 system is an important step forward in providing a hybrid-electric propulsion system that will enable a new class of quieter and cleaner air transport.”

Transforming transport

Rolls-Royce engineers based in the United States, UK and Singapore have developed the gas turbine engine into a hybrid-electric propulsion system. The M250 has powered more than 170 varieties of fixed-wing military, civilian aircraft and helicopters since its initial development.

The tests included simulating use across take-off, cruise, landing and taxiing. Rolls-Royce says they confirm the system’s suitability for a range of transport platforms including aircraft with a range of up to 1,000 miles and weighing up to 2000kg. This would support the Rolls-Royce eVTOL concept which was unveiled at Farnborough Air Show last year.

Dr Mekhiche added: “Electrification is one of the most exciting developments in aviation since the birth of the jumbo jet.

“We are determined to use our pedigree in aerospace to be at the forefront of developing innovative propulsion systems to meet the needs of the next chapter in aviation. When this happens, it’s going to transform the way aero transport is designed and produced, reducing the time required to travel, revolutionising cargo delivery and changing the way we design our cities and infrastructure.”

The next step is to further advance the hybrid propulsion system towards integration on an aircraft and experimental flights in 2021. The M250 hybrid power pack complements the AE 2100 2.5MW system being developed for larger aircraft, including regional aviation, and is being tested with Airbus on the E-Fan X demonstrator platform.

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