GE, Safran Launch Green Open-rotor Engine Development

 - June 14, 2021, 11:44 AM
The CFM Rise program envisions a family of engines using a single open-rotor architecture. (Image: Safran)

GE Aviation and Safran on Monday launched a technology demonstration and maturation program under their CFM joint venture for a family of open-rotor engines that would run on either 100 percent sustainable aviation fuel (SAF) or liquid hydrogen by the middle of the next decade. Called Rise (Revolutionary Innovation for Sustainable Engines), the development program aims for a 20 percent improvement in fuel burn and CO2 emissions compared with today’s CFM Leap family.

CFM foresees ground testing on engine modules at GE and Safran facilities starting in the middle of this decade, followed by flight testing on a GE testbed “soon thereafter,” according to Safran CEO Olivier Andriès, who, along with GE Aviation chief executive John Slattery hosted an online briefing during which they also announced the extension of the CFM partnership until 2050.

Andriès stressed that the Rise announcement did not amount to an engine launch but rather a formal commitment to continue with studies for a Leap successor on which GE and Safran have collaborated since 2019. Also appearing at the online event, GE Aviation vice president of engineering Mohamed Ali called the 20 percent fuel burn and CO2 reduction target “the single largest improvement” the companies will have ever made. Technologies under study include advances in architecture and materials as well as hybrid electrification for both the engine and airframe systems.

A joint GE-Safran engineering team has laid out what the companies call a comprehensive technology roadmap, including composite fan blades, heat-resistant metal alloys, ceramic matrix composites (CMCs), and additive manufacturing. The Rise program includes more than 300 components, modules, and full engine builds.

“There are so many new technologies that are coming on to the program,” said Slattery. “If you start with the open fan, which we have a lot of tacit knowledge between both organizations on…of course, it will be hybrid electric. There will be a lot of new materials that we'll be bringing. We would have a gear on this engine, of course, because it's open-rotor.”

The companies plan to use a single rotor in their plan, as opposed to counter-rotating designs considered in past studies, including GE’s UDF in the 1980s and, more recently, Safran’s open-rotor studies developed through Europe’s Clean Sky research program in 2017.

“We recently have been able to use these learnings, in both companies, in addition to a tremendous utilization of computational power that became more recently available,” added Ali. “And now we are able to actually make it a single fan…and design blades specifically for that. That not only reduces the weight and reduces the complexity; it opens up the efficiency as well as it creates the same comfort from a noise perspective that all the passengers have become used to.” Andriès added that this open-rotor design would result in no more noise—either internally or externally—than today’s Leap.

Although Andriès wouldn’t estimate an investment cost for the project, he noted that Safran has committed to dedicating 75 percent of its research and development budget to sustainability and stressed the importance of government partnerships, which, he said, he fully expects the European Commission to endorse. Slattery, meanwhile, promised GE would commit a “significant” portion of its R&D budget, which reached $1.8 billion last year and will again in 2021.