Rolls-Royce is launching a new leading-edge hydrogen program and also given a further update on its research into hybrid-electric power as it continues to pioneer new forms of aviation sustainability.

Rolls-Royce is planning a comprehensive series of rig and engine tests to prove hydrogen can safely and efficiently deliver power for small-mid size aircraft from the mid-2030s onwards. The company has further ambitions to move this on to a flight test phase as part of the program in the long term.

Two ground tests are planned: on a Rolls-Royce AE 2100 engine in the UK this year and a Rolls-Royce Pearl 15 jet engine at a future date. A range of location options are being assessed for this including the Rolls-Royce test facility in Mississippi. This will build on hydrogen combustion tests already well underway in partnership with Loughborough University and German research institute DLR, with Cranfield University’s input on fuel system management.

Artist’s impression of a hydrogen engine ground test.

The program follows market research carried out by the UK Aerospace Technology Institute’s Fly Zero team and Project NAPKIN (New Aviation Propulsion Knowledge and Innovation Network), both of which had Rolls-Royce representation, and both concluded there is market potential for hydrogen-powered aircraft.

It also complements broader research into hydrogen infrastructure and transportation that Rolls-Royce is already carrying out with easyJet.

Hybrid-electric and hydrogen power systems are also part of a regional aircraft research project underway with WiderØe and Embraer.

Rolls-Royce’s hybrid electric research has been carried out on the Power Generation System 1 (PGS1) demonstrator, made up of an AE 2100 engine with specialist controls and thermal management systems.

Tests in Bristol, UK, and Trondheim, Norway, recently concluded and have now confirmed the system delivered more than 1.5 megawatts of power—the first time this has been achieved in the aviation sector.

Rolls-Royce is now taking that huge amount of learning and carrying out further work to understand how a production version of PGS1 might be achieved and discussing with airframers what their future requirements may be.

We are pioneers of power and this program puts us in a great position to pave the way to make hydrogen and hybrid-electric systems a reality. 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.

—Chris Cholerton, President – Civil Aerospace, Rolls-Royce

UltraFan. Separately, Rolls-Royce announced it has entered the final build phase for the world’s largest aero-engine technology demonstrator, UltraFan. The demonstrator engine, with a fan diameter of 140 inches, is being completed at the facility in Derby, UK, prior to its first run on 100% Sustainable Aviation Fuel (SAF) later this year. It offers a 25% fuel efficiency improvement compared with the first generation of Trent engine.

UltraFan supports a variety of sustainability solutions. In the nearer term, there are options to transfer technologies from the UltraFan development program to current Trent engines to deliver even greater fuel efficiency and reductions in emissions.

In the longer term, UltraFan’s scalable technology from 25,000-100,000lb thrust offers the potential to power new narrowbody and widebody aircraft anticipated in the 2030s.

UltraFan provides a platform for the use of a diverse range of energy options and power systems including current jet fuel and sustainable aviation fuels as well as future potential for hybrid-electric and hydrogen.

Key engineering features of the engine include:

• A new, proven, Advance3 core architecture, combined with ALECSys lean burn combustion system, to deliver maximum fuel burn efficiency and low emissions;

• Carbon titanium fan blades and a composite casing;

• Advanced ceramic matrix composite (CMC) components that operate more effectively at high pressures and temperatures; and

• A geared design that delivers efficient power for the high-thrust, high bypass ratio engines of the future. The power gearbox has run at 64MW, an aerospace record.

When UltraFan is on test at Rolls-Royce’s new £90m Testbed 80 facility, data can be taken from more than 10,000 parameters, detecting the tiniest of vibrations at a rate of up to 200,000 samples per second.