CFM International joint-venture partners GE Aerospace and Safran have completed the conceptual design review for the next-generation RISE (Revolutionary Innovation for Sustainable Engines) open fan propulsion system which targets a 20% improvement in fuel efficiency compared with its current Leap 1 turbofan.
“We are working full speed at CFM. RISE is no longer some kind of a concept for the future—this is our day-to-day work,” CFM CEO Gael Meheust says, updating on progress to coincide with the Dubai Airshow. “We have performed a conceptual design review already and we are starting to cut metal to produce parts with the goal of running a demonstrator and perform flight tests later in this decade.”
More than 100 tests have been carried out as part of a technology maturation phase, and over 1,000 engineers are now engaged in the design of the demonstrator. “We are learning a lot and are pleased with the results we are achieving,” Meheust says. As well as a 13-ft.-dia. open fan, the demonstrator will also include a high-power gear system and a new compact high-pressure (HP) core to boost thermodynamic efficiency. The initial fan set will, however, be tested with a modified GE Passport business jet engine as the gas generator.
The RISE program will also include a recuperating system to preheat combustion air with waste heat from the exhaust as well as the application of advanced materials such as ceramic matrix composites in the hot section and resin-transfer molded composite fan blades. Initial evaluations of the first rotating components of RISE began earlier this year when tests of the first full high-speed low-pressure turbine stage got underway at GE’s facility in Evendale, Ohio, using an F110 military donor engine. Supercomputers are also being employed to test the design of the HP turbine blades and nozzles.
CFM’s RISE program also includes hybrid-electric and hydrogen studies and puts it “on track to be the first company to introduce hybrid electric in the single-aisle segment,” CFM says. Tests conducted recently at NASA’s Electric Aircraft Testbed facility in Sandusky, Ohio, as part of the agency’s Electrified Powertrain Flight Demonstration project, have already validated GE’s hybrid-electric propulsion system architecture approach and pave the way towards tests of a mildly hybridized turbofan as part of the RISE program.
Under an agreement signed in February 2022, Airbus and CFM also plan to flight-test a GE Passport engine modified for direct combustion of hydrogen fuel. The tests, scheduled for around 2026, form part of the RISE effort and are intended to prove technology for entry-into-service on the first of several generations of planned Airbus zero-emission aircraft by 2035. “We have included hydrogen in our test plans and we will work with airframers and specially Airbus to see how this can fit into a flight test of an airplane,” Meheust says.
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