Type Open rotor engine
National origin France and United States
Manufacturer CFM International
Status Under development

The CFM International RISE ("Revolutionary Innovation for Sustainable Engines") is an open rotor engine currently under development by CFM International, a 50–50 joint venture between American GE Aerospace and French Safran Aircraft Engines. The engine is planned to support both hydrogen and sustainable aviation fuels, and it plans to achieve a 20% reduction in fuel burn and in carbon dioxide emissions compared to its predecessors.[1][2][3]



The 1973 oil crisis increased oil prices in the 1970s, which caused engine manufacturers to research new technologies to reduce fuel burn, including open rotor (also known as propfan) engines. However, none of those designs made into production aircraft, mostly due to decreasing oil prices and concerns over the high noise footprint of those engines.[4][5][6]

Both Safran and GE Aviation had experimented with open rotor based engine designs in the years before the RISE project was announced. Safran had performed ground tests for an open rotor engine in 2019 as a part of the European Union's Clean Sky project, while GE had performed wind tunnel tests on a derivative of the GE36 engine at the start of the 2010s in collaboration with the Federal Aviation Administration.[1][6]

Program announcement

CFM International announced the RISE program in June 2021 as an intended successor of the CFM LEAP turbofan engine, with plans to enter service in the mid-2030s. At the 2022 Farnborough Airshow in July of that year, CFM International and Airbus announced plans to start flight tests for the RISE engine on an Airbus A380-based testbed in 2026.[7][8]

In June 2023, General Electric tested the first rotating components of the new engine, mating the first high-speed, low-pressure turbine stage to a GE F110 military test engine.[9] As of late 2023, GE was producing test parts toward the goal of producing a demonstrator engine for flight testing. The demonstrator would pair an open fan set with a GE Passport gas generator.[10]


Unlike the GE36 and PW-Allison 578-DX contra-rotating engines that were proposed in the 1980s and Safran's open rotor engine in the 2010s, the RISE has only a single-stage open rotor. The open rotor stage is followed by a non-rotating stage of stator vanes. The two stages have variable pitch control. The RISE has a tractor configuration that pulls the aircraft into motion, unlike the pusher configuration of those other engines.[1] The single-rotating design had previously been validated by the IRON project as part of the Clean Sky 2 program,[7] and GE had dubbed the concept as the Unducted Single Fan (USF) engine.[11] The fixed stator vanes vary their pitch to deswirl the flow, and they close almost completely together to act as an air brake, avoiding the need for a thrust reverser.[12] The RISE will also use a recuperator, which captures waste heat from the exhaust gas to pre-heat the air that exits the compressor before it enters the combustor.[10]


See also

Related development

Related lists


  1. ^ a b c Norris, Guy (June 14, 2021). "CFM Unveils 'Open Fan' Demonstrator Plan For Next-Gen Engine". Aviation Week Network. Retrieved February 26, 2023.
  2. ^ Huston, John (June 17, 2022). "Boeing Keeps an "Open Mind" on RISE Engine Technology". Airways Magazine. Retrieved February 26, 2023.
  3. ^ Gates, Dominic (June 15, 2021). "'Open Rotor' engine for sustainable aviation". techxplore.com. Retrieved February 28, 2023.
  4. ^ "The Short, Happy Life of the Prop-fan". Smithsonian Magazine. Retrieved February 28, 2023.
  5. ^ Georgilidakis, Spyros (February 27, 2021). "Safran Open Rotor – The Next Engine Design Leap?". Mentour Pilot. Retrieved February 28, 2023.
  6. ^ a b Fehrm, Bjorn (January 3, 2020). "Bjorn's Corner: Why e in ePlane shall stand for environment, Part 3. Open rotor revisited". Leeham News and Analysis. Retrieved February 28, 2023.
  7. ^ a b Fehrm, Bjorn (June 14, 2021). "CFM announces the RISE engine program". Leeham News and Analysis. Retrieved February 26, 2023.
  8. ^ Norris, Guy (July 19, 2022). "Airbus To Flight-Test CFM RISE Open Rotor". Aviation Week Network. Retrieved February 26, 2023.
  9. ^ Norris, Guy (June 17, 2023). "CFM RISE: Supercomputers boost promise for design and performance". Aviation Week. ISSN 0005-2175. Retrieved December 4, 2023.
  10. ^ a b Norris, Guy (November 13, 2023). "CFM RISE open fan passes conceptual review milestone". Aviation Week. ISSN 0005-2175. Retrieved December 4, 2023.
  11. ^ Rostagno, Stefano (June 2018). "European propulsion on the horizon". about: The Avio Aero people's magazine.
  12. ^ Gates, Dominic (June 19, 2023). "The new engine design touted to power the successor to Boeing's 737 MAX". Seattle Times. ISSN 0745-9696.
  13. ^ Beresnevicius, Rytis (June 22, 2023). "CFM's open fan RISE engine to power Boeing X-66A". AeroTime. Retrieved July 26, 2023.