If the European aerospace industry wants to have hydrogen and hybrid-electric airliners ready to enter service by 2035, it has to make sure that it decides on the required technology bricks no later than 2025 and 2026. It is absolutely necessary to push forward in the next few years and use synergies and collaborate where possible. Clean Aviation needs to solve 'technology bricks' by 2026. That is one of the takeaways from the two-day Clean Aviation Forum in Brussels on March 22 and 23. The European Union and industrial partners used the event to physically kick off the latest Clean Aviation technology program, which was launched in December and runs in two phases until 2030. The European Commission contributes to the program with €1.7 billion, with another €2.4 billion to be contributed by industrial partners and research agencies, and universities. Some 45 percent of the funding (€735 million) will be in Phase 1 until 2025, the remainder in Phase 2 until 2030. The aim of the forum was to call on participants to join the Clean Aviation Joint Undertaking and send in proposals until June 23, with a final selection to be expected in September. Clean Aviation follows the roadmap of the Air Transport Action Group on getting to net-zero by 2050. (Clean Aviation) Clean Aviation builds on the Clean Sky 1 and 2 programs from the past decade which have resulted in many technology programs on propulsion efficiency, aerodynamics, structures, and aircraft systems. But as Nathalie Duquesne, managing director at Liebherr Aerospace, reminded, “in Clean Sky 1 and 2, we were not talking about sustainable aviation fuels (SAF), we were not talking about hydrogen, but always about how to reduce fuel consumption. Which was good, as it is necessary.” But since the launch of Clean Sky 2 in 2014, there is now a clear commitment from the European Union to become carbon net zero in 2050. “It has been said before: we need two ways to get to net-zero by 2050: we need SAFs and we need hydrogen”, said Laurent Thomasson, Clean Aviation coordinator at Airbus. “The road to 100 percent SAF is truly important to reach. We want to be fully compatible with 100 percent SAF between 2025 and 2030.” But hydrogen is very clear on Airbus’ radar with the ZEROe program. During an online speech on day 1 of the forum, CEO Guillaume Faury reconfirmed the intention to bring a hydrogen airliner to the market in 2035, for which it has identified various R&D steps until 2027 to 2029. While some steps will be steep, Airbus has no intention to have it steal its thunder from a start-up rival: “We won’t be the ones giving the ‘Tesla moment’ to others by bringing a hydrogen plane to the market.” This is a bold step, as Clean Aviation’s Head of Strategic Development, Rob van Manen, said: “If you would have mentioned hydrogen four years ago, you probably would have been escorted to the door.” 'Collect the most promising solutions' “Compared to the past, we are in a situation where the impact (of aviation) is the driver. We are no longer in a technology-push environment, we are now in an impact-driven environment”, said Marco Protti, Head of Advanced Research of Leonardo. “We need to do our best to collect the most promising solutions to de-risk them during the duration of Clean Aviation and to test them in conditions that are representative of the real applications. This implies we have to down-select quite a number of solutions and keep in mind the key date of 2025-2026 for the maturation of the technology bricks.” This requires that the private and public sectors work together in a more advanced way than in Clean Sky, said Protti. The main areas of interest of Clean Aviation are hybrid-electric regional aircraft, ultra-efficient short- and medium-haul range aircraft, plus disruptive technologies like hydrogen fuel cells and direct combustion. The development of a long-haul aircraft comes at a later stage. A lot of research has already been done under Clean Sky 2 and is ongoing, like the Rolls-Royce Ultrafan that will start ground tests in July, various helicopter and aircraft demonstrator projects from Airbus, Dassault, and Leonardo, or system and engine research from MTU Aero engines or German Aerospace Center (DLR). But some fourteen ‘bricks’ need further research to get to the launch of an aircraft project, for which an aggregate of €12 billion will be needed, so Clean Aviation is providing only one-third of that. As far as hydrogen is concerned, Airbus has identified four pillars for further research: “The first is getting the benefit of directly burning hydrogen in an engine, the fuel cell system, the power system, and electric motors, and the hydrogen storage systems”, Thomasson summed up. But Clean Aviation could also contribute with new solutions for cryogenic technologies, although there is more time to mature this. Don't forget to study thermal heat Liebherr’s Duquesne stressed the importance of getting a better understanding of thermal management of hydrogen systems like fuel cells: “Each time you generate one kilowatt of electricity, you generate almost one kilowatt of heat. This hasn’t been mentioned so far. Thermal management will be one, big challenge on the new generation of aircraft, as there will be so many (heat) loads on the aircraft. We have to deal with that.” Some of the key improvements Airbus' Laurent Thomasson hopes to take away from Clean Aviation. (Clean Aviation) Thomasson also mentioned improvements needed in fuselage structures and materials. Airbus and DLR recently completed the production of a thermoplastic, multi-functional fuselage demo lower shell skin of 8.5 by 4 meters which has been part of a Clean Sky 2 program that will continue until the end of 2023. Mastering these new structures will help contribute to the small regional aircraft program under Clean Aviation. At the end of his presentations, Laurent Thomasson summed up what Airbus hopes to get from Clean Aviation: “We don’t want just a nice prototype. We want something that can be produced in a cost-competitive manner. It is you who will make your proposals, but what we expect of Clean Aviation is to have goods product for ‘smart’ wings that perform twelve to fifteen percent better, cost-competitive solutions for a more integrated fuselage, we need a highly-efficient, integrated thermal propulsion system, and, of course, we need to have this disruptive improvement in fuel efficiency." No overlap with other technology programs The call for proposals of Clean Aviation comes just on the back of the exhaustive FlyZero study for three hydrogen aircraft from the UK Aerospace Technology Institute (ATI), with DLR to present its EXACT technology pathway on March 31. This sounds like a lot of research programs that might have some overlap, but Rolls-Royce Director of Aerospace Technology and Future Programs, Allan Newby, doesn’t agree. “It’s quite the opposite. One of the things of these programs is building synergies. Some of the technologies we developed for UltraFan, we developed through ATI programs and we brought the demonstration program together within Clean Sky. I think you will see the same in hydrogen as well, with some of the elementary work done at universities in Germany of the UK, and then bring some of the concepts within the EU program. So it’s very much complimentary. And there is never enough money. If we start to optimize how to use money from the national programs and Clean Aviation, then we begin to address all of those risks.”
