RTX engineers are pushing the limits of aviation with promising new initiatives that may soon bring hydrogen fuel technologies to the aircraft industry.
In the last two years, RTX (formerly Raytheon Technologies Corporation) has pursued various projects with international collaborators that have produced significant gains in hydrogen applications for aviation. The company’s latest work lays out the path for industry-wide adoption once hydrogen fuel becomes readily available.
From January to December 2024, a team from the RTX Technology Research Center in East Hartford, Connecticut, worked on the Hydrogen Steam Injected Intercooled Turbine Engine project, referred to as “HySITTE. ” The site hosted an aviation test rig, where natural gas flowed into a combustor, generating a flame that altered from blue to red when switched over to hydrogen. The mock engine allowed engineers to study the heat and pressure of their hydrogen-powered designs.
“It’s one of these rare times you get to see something that’s really new,” said Lance Smith, an RTX senior technology fellow, reflecting on the team’s first successful hydrogen ignition. “But then you knuckle down and make sure it’s right.
“You can burn hydrogen, clean,” Smith said after thorough analysis and double-checking. “You can burn it safely and robustly. You’re not going to burn up the combustor, but you can take this explosive, highly flammable gas and put it in a combustor and burn it safely and stably. And it comes in a package that is super efficient. The takeaway is there’s a solution here.”
Hydrogen-Powered Projects Expand
The US Department of Energy’s Advanced Research Projects Agency-Energy funded the HySITTE program, which was nestled under RTX subsidiary Pratt & Whitney. The program aimed to develop an industry-wide-scale hydrogen fuel technology for aviation. Uniquely, HySITTE emphasized liquid hydrogen, minimizing nitrogen oxide emissions, and maximizing efficiency by capturing engine exhaust water. Across RTX’s many divisions and subsidiaries, the company is pursuing several hydrogen-powered aviation concepts.
Following on from the December 2024 conclusion of HySITTE, RTX is presently engaged in the US and Canadian collaboration, Hydrogen Advanced Engine Study (HyADES), and COCOLIHT2T in an EU partnership. HyADES aims to use hydrogen for turboprop aircraft, while COCOLIH2T is advancing fuel storage capabilities.
HySITTE Demonstrated Impressive Performance
The HySITTE rig performed as expected, or in some instances even better than expected. Tests showed a 99.3% reduction in nitrogen oxide emissions as the condenser captured one gallon of water every three seconds. Overall, the design improved performance by 35%.
“It was like a low roar – a bit like being in a plane – that low roar of the air rushing past,” Jacob Snyder said regarding tests to ensure the evaporator was resilient enough to handle the challenging conditions of jet exhaust. “There was a non-zero chance this thing would explode. When it survived the testing with flying colors, there was a big sense of relief.”
“The fact that all the tests came back better than expected really made us think this technology could be a viable option for the future of hydrogen,” he continued.
“There are a handful of times in your career when you do something new and exciting and this is one of them,” said Smith. “It’s not that often you get to try out a whole new concept. At the end of a career, that’s a highlight. That’s an accomplishment you carry with you.”
Toward a Hydrogen-Powered Future
While the technology is promising, RTX is still looking ahead to the day when hydrogen fuel will proliferate across the aviation industry.
“We are understanding the value,” said Michael Winter, chief scientist at RTX. “HySIITE is the most realizable architecture for the future of hydrogen fuel and propulsion at scale. If hydrogen becomes widely available, Pratt & Whitney will be ready for that future.”
“Whatever new technologies we bring forward, they need to be more safe than anything flying today and they need to provide better customer value,” he continued. “If I had an engine that was 35% more efficient, that translates into a dramatic savings for our customers, the airlines, and the air force of our nation and our allies.”
For Winter and his colleagues, a primary goal is to demonstrate some of the most difficult but also potentially crucial new technologies that could lead to additional industry breakthroughs.
“We choose the hardest technology challenges,” Winter says, “and we actively choose to demonstrate those first.”
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.