UK-based global major propulsion and power system group Rolls-Royce announced on Monday (the first day of the 2022 iteration of the renowned Farnborough Air Show in England) that it had launched a cutting-edge programme to use hydrogen as a fuel for commercial aircraft. The company also provided an update on its development of hybrid-electric aircraft propulsion systems.

The decision to launch the hydrogen power programme was not taken in isolation. It followed market research carried out by the Fly Zero team of the UK Aerospace Technology Institute (a public-private partnership) and by the Heathrow Airport Limited-led NAPKIN (New Aviation Propulsion Knowledge and Innovation Network) consortium. Rolls-Royce was a member of both initiatives. Both these projects established that there was market potential for aircraft fuelled by hydrogen.

These results complemented those of a joint Rolls-Royce/easyJet programme into hydrogen infrastructure and transport questions. Rolls-Royce further had a joint project with Brazil-based airframer Embraer and Norwegian regional airline Widerøe into the use of both hydrogen and hybrid-electric power systems on aircraft.

“We are pioneers of power and this programme puts us in a great position to pave the way to make hydrogen and hybrid-electric systems a reality,” affirmed Rolls-Royce Civil Aerospace president Chris Cholerton. “Combined with our work on sustainable aviation fuel and further gas turbine efficiency, we are making real progress on the hard yards of research and development towards making net zero flight a reality.”

Regarding hydrogen, the group was going to undertake comprehensive rig and engine tests to prove that it could safely be used, from the mid-2030s, as a fuel for small to mid-sized aircraft. Currently, two ground tests of Rolls-Royce engines were planned. The first of these would involve an AE2100 turboprop engine (developed and manufactured by Rolls-Royce North America); these tests would be run in the UK. The second would involve a Pearl 15 turbofan (developed and manufactured by Rolls-Royce Deutschland specifically for business jets) and would be held some time in the future, following the selection of a test site (a process that was currently under way, with one option being the group’s test facility in the US State of Mississippi). In the longer term, there were ambitions for a flight test.

These tests would benefit from a hydrogen combustion test programme that was already progressing. This programme involved a partnership of Rolls-Royce, Loughborough University (in the UK) and Germany’s DLR aerospace research institute, with Cranfield University (also in the UK) providing expertise regarding fuel system management.

Regarding hybrid-electric propulsion, Rolls-Royce had been carrying on research using its Power Generation System 1 (PGS1) demonstration system. This was composed of an AE2100 engine, plus specialist controls and thermal management systems. A recently-concluded test programme, divided between sites in the UK (in Bristol) and Norway (in Trondheim) had confirmed that the PGS1 had delivered power exceeding 1.5 MW – a first for the aviation sector. Rolls-Royce was now studying how a production version of the PGS1 could be developed, while also talking to airframe manufacturers about their future requirements.