The open fan propulsion system will be flight-tested on an A380.
Guy Norris
Credit: Airbus
CFM International has agreed with Airbus to flight-test the open fan propulsion system being developed under the engine-maker’s Revolutionary Innovation for Sustainable Engine (RISE) program on the A380.
CFM, the joint venture between GE and Safran Aircraft Engines, says the flight-test campaign will be performed in the second half of this decade from the Airbus Flight Test facility in Toulouse, France. The company adds that ahead of the A380 test flights, CFM will perform engine ground tests, along with flight-test validation on GE’s Boeing 747-400 flying testbed at GE Aviation’s Flight Test Operations center in Victorville, California.
Mounted on the left inboard position on the Airbus double-decker, the flying testbed will be the second of two A380s associated with the RISE test program. Under an agreement signed in February, 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 wider RISE effort and are intended to pave the way for entry-into-service of the technology on the first of several generations of planned Airbus zero-emission aircraft by 2035.
Both A380s will require significant modifications for the two RISE efforts. The open fan demonstrator will be fitted with a large support pylon and reinforced inboard wing structure to accommodate the CFM engine, which is currently expected to feature a rotor diameter of around 13 ft. The hydrogen demonstrator will be modified to carry the Passport on a pylon projecting from the aft fuselage of the A380, while the interior will be equipped with liquid hydrogen tanks.
Targeting a 20% reduction in fuel consumption and CO2 emissions compared to current engines, RISE is aimed at a successor to the current Leap 1 turbofan in the 20,000-35,000-lb. thrust class. The RISE open fan will include a new compact high-pressure core to boost thermodynamic efficiency, as well as a recuperating system to preheat combustion air with waste heat from the exhaust. The demonstrator will also incorporate the use of advanced materials such as ceramic matrix composites in the hot section and resin transfer-moulded composite fan blades.
A distinctive new feature of the open fan is a second non-rotating stage of active variable-pitch stators that will act as flow-recovery vanes. The design increases overall fan pressure ratio while simultaneously reducing rotor loading, thus enabling higher maximum flight Mach number. The rotating front stage will be powered by a high-speed booster compressor and connected to the turbine via a high-speed, low-pressure-shaft-driven front gearbox.
In related news at Farnborough, GKN Aerospace has also announced it has entered into a Joint Technology Development Program (JTDP) with GE to collaborate in the development and maturation of the open fan architecture for RISE. No specific details of what GKN will contribute have been released, although the company says it will be involved “through the injection of its latest technologies, component design, and production of hardware adapted to support the program targets, as well as the validation plan for the program.”
