MTU Aero Engines continues to make steady progress on two parallel fuel cell powertrain projects, as it builds towards full system tests over the next two years.
An internally funded programme, the Flying Fuel Cell (FFC) sees MTU developing a 600kW powertrain, including an electric motor.
A critical design review for the system has now been concluded and the company is moving to component manufacturing – including the fuel cell stacks – and assembly.
Separately, tests of the 600kW electric motor for the powertrain have begun.
Developed by subsidiary eMoSys – a business acquired by MTU in 2023 – the motor was recently run at its maximum continuous output for the first time.
“The tests confirmed a high efficiency rate of more than 96%, both during take-off and at cruising altitude,” says Barnaby Law, FFC head engineer at MTU.
In support of the FFC development, MTU is standing up new test facilities for the FFC at its Munich site.
A fuel cell stack test cell, suitable for 500kW stacks, was recently commissioned, while a test facility for the full powertrain is now under construction.
Meanwhile, MTU is also leading a separate project, part funded through the EU’s Clean Aviation initiative, to develop a 1.2MW fuel cell powertrain ground demonstrator.
Called HEROPS, the effort sees MTU heading a consortium that also includes Collins Aerospace, Eaton Lufthansa Technik, and MT Aerospace, alongside research collaborators the Royal Netherlands Aerospace Centre and the Vienna University of Technology.
Running from January 2024 until December 2026, HEROPS is receiving €29 million ($33 million) from Clean Aviation against a total budget of €40 million.
Based around MTU’s core FFC technologies, the system should ultimately be scalable to the 2-4MW level, Clean Aviation project requirements state.
“The two-phase approach of the overall programme – including extensive development, test and validation cycles at each stage – is expected to advance the FFC concept to TRL6 for integration and demonstration on a regional aircraft by 2028,” it says.
Potential exploitation of the system on regional aircraft is targeted for around 2035.
MTU says it has now completed the preliminary design review milestone for the HEROPS system.
“This marks a substantial step towards confirming the fundamental feasibility of scaling up our fuel cell technology,” says Dr Dominik Wirth, chief engineer of HEROPS.
“Having established the essential functional, performance, safety, and interface requirements for the various subsystems, we will now focus on further developing and optimising this megawatt-class fuel cell engine concept.”
MTU expects to finalise the design by year-end, dedicating 2026 to the “experimental validation of core technologies”.
Planned activities will include a series of component tests and windtunnel evaluations of the integrated engine nacelle, propeller, and heat exchanger system.
