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Last month, Rolls-Royce and easyJet completed a full hydrogen-powered flight cycle on a Pearl 15 engine<\/a> at NASA\u2019s Stennis Space Center.<\/p>\n Beyond showing that a modern jet engine could run safely on hydrogen in a ground-test environment, the campaign helped prove that a hydrogen-powered gas turbine could still behave like a normal aero engine.<\/p>\n On the ground at NASA was Adam Newman, Chief Engineer for the Hydrogen Demonstrator Programme at Rolls-Royce. Speaking exclusively to AGN, he described the campaign as an \u201camazing experience\u201d and the \u201chighlight\u201d of his career.<\/p>\n \u201cThe flight cycle was a real statement piece,\u201d Newman said. \u201cWe wanted to show that we could run an aero gas turbine like an aero gas turbine. In the full flight cycle, we could do the operability, the accelerations, decelerations\u2026 That was really key.\u201d<\/p>\n The test marked a leap from Rolls-Royce\u2019s first hydrogen engine run in 2022<\/a>, using an AE2100 engine.<\/p>\n \u201cThat was largely to idle and to show some of those real fundamental basics,\u201d Newman said. \u201cThis was to show the progression in a short period of time.\u201d<\/p>\n The more significant question now is what the test says about the future of hydrogen propulsion, and why Rolls-Royce<\/a> is pursuing hydrogen combustion rather than the fuel-cell route being explored elsewhere in the industry.<\/p>\n Why Rolls-Royce sees hydrogen combustion as the solution for large aircraft<\/p>\n Hydrogen fuel cells have attracted significant attention in aerospace<\/a>. These use hydrogen to generate an electric charge, which is then used to power propellers or motors for aircraft.<\/p>\n But the modest power output of these technologies, for now, means they\u2019re limited to smaller aircraft<\/a>. Rolls-Royce, for many years, has been a major powerhouse behind some of the largest aircraft on the planet, and was considering markets beyond regional propeller aircraft.<\/p>\n \u201cThe reason we are looking at gas turbines combusting hydrogen rather than fuel cells is the size of aircraft we\u2019re looking to power,\u201d Newman said. \u201cThe inconvenient truth, I guess, for the fuel cell manufacturers, is that the gas turbine is unbeatable in terms of power density.\u201d<\/p>\n Rolls-Royce\u2019s Pearl 15 is one of the company\u2019s smaller gas turbines, powering aircraft such as the Bombardier Global 5500 and Global 6500 business jets. Yet even that engine produces more than 10MW of equivalent power.<\/p>\n By comparison, he said, fuel-cell systems are typically much smaller.<\/p>\n \u201cYou look at some of the fuel cells that are publicly available at the moment, and they\u2019re maybe one to two megawatts,\u201d Newman noted. \u201cSo perhaps a tenth of the size of the gas turbine that we ran.\u201d<\/p>\n It\u2019s not that Rolls-Royce doesn\u2019t see a future for fuel cell technology in aviation, just that it\u2019s not the right solution for the markets where Rolls-Royce plays hard \u2013 large passenger aircraft.<\/p>\n \u201cWe power business jets, but they\u2019re quite a small part of our market,\u201d Newman explained. \u201cReally, it\u2019s narrowbody all the way up to widebody. That\u2019s where engines start to become in the 30,000 lb to 100,000 lb thrust range. That\u2019s typically where Rolls-Royce sets itself out to major in the civil aero market.\u201d<\/p>\n For aircraft of this scale, power density becomes a priority. Batteries are too heavy for larger commercial aircraft. Fuel cells have a role, but scaling them to high-thrust commercial aviation remains difficult. Gas turbines, for all their complexity, already provide the thrust levels aviation needs.<\/p>\n The engine might not be the hardest part of hydrogen aviation<\/p>\n Although the Stennis campaign demonstrated a major propulsion milestone, Newman is clear that hydrogen aviation remains a much bigger challenge than the engine alone.<\/p>\n \u201cThere are big pockets of challenge,\u201d he said. \u201cIt\u2019s a whole ecosystem challenge.\u201d Even so, Rolls-Royce wanted to tackle the powerplant problem first.<\/p>\n \u201cWe really wanted to set our stall on the powerplant and address some of those fundamental powerplant challenges,\u201d Newman said. \u201cParticularly myth-busting some of the things around non-CO2 effects<\/a>. There are a lot of people who say hydrogen combustion will never work because of X, Y, Z, and we\u2019ve gone off to try and prove some of those things as untrue, or quantify them much more accurately so we can have a better-informed conversation.\u201d<\/p>\n Beyond the engine, the bigger questions are aircraft integration, fuel storage and infrastructure. At aircraft level, storing the fuel could require large tanks, with future aircraft likely to use liquid hydrogen stored at cryogenic temperatures for at least part of the fuel system.<\/p>\n \u201cThere are real challenges around storage,\u201d Newman said. \u201cThere are a number of projects looking at how you can store hydrogen on an aircraft at what we call a gravimetrically efficient level: how much is the weight of the fuel system versus the weight of the fuel. That\u2019s a challenge.\u201d<\/p>\n Then comes the airport and supply-chain problem. Newman suggested hydrogen aviation may not require every airport in the world to be hydrogen-ready from day one. A more targeted rollout could be possible, particularly in Europe.<\/p>\n \u201cYou could choose these hub-and-spoke type models, where you could be a bit more targeted around where you do your initial investment and still have, certainly in Europe, really good coverage.\u201d<\/p>\n What comes next for Rolls-Royce after the Pearl hydrogen test?<\/p>\n For all the optimism around the Stennis test, Rolls-Royce is not presenting hydrogen as an imminent commercial solution.<\/p>\n \u201cHydrogen is part of the energy mix, but it\u2019s probably going to be the later part, the 2040s into the 2050s,\u201d Newman said. \u201cThings like UltraFan can have a much bigger impact in the nearer term.\u201d<\/p>\n![\"Rolls-Royce](\"https:\/\/www.europesays.com\/britain\/wp-content\/uploads\/2026\/05\/262622029_Rolls-Royce-easyjet-hydrogen-engine-tests-683x1024.jpg\")
Photo: easyJet<\/p>\n![\"Rolls-Royce](\"https:\/\/www.europesays.com\/britain\/wp-content\/uploads\/2026\/05\/Rolls-Royce-Pearl-15-engine-for-hydrogen-tests-1024x738.jpeg\")
Photo: Rolls-Royce<\/p>\n![\"Rolls-Royce](\"https:\/\/www.europesays.com\/britain\/wp-content\/uploads\/2026\/05\/262622119_Rolls-Royce-easyjet-hydrogen-engine-tests-1024x683.jpg\")
Photo: easyJet<\/p>\n![\"Rolls-Royce](\"https:\/\/www.europesays.com\/britain\/wp-content\/uploads\/2026\/05\/52906659672_f464882abb_k-1024x760.jpeg\")
Photo: Rolls-Royce<\/p>\n
![\"Rolls-Royce](\"https:\/\/www.europesays.com\/britain\/wp-content\/uploads\/2026\/05\/53408538710_9535ab3f46_k-1024x684.jpeg\")
Photo: Rolls-Royce<\/p>\n