Boeing has selected the General Electric GE9X to exclusively power the 777X to extend the engine maker's propulsion monopoly to the next generation of the 777 widebody.
The decision means Boeing has rejected the Rolls-Royce RB3025 turbofan after Pratt & Whitney opted not to bid a widebody-sized version of the PurePower PW1000G geared turbofan.
It also moves the airframer one step closer to formally offering the aircraft to customers and launching the aircraft to appear in service at the end of this decade.
"We are aggressively moving forward on our plan and will continue to refine requirements with customers," says Bob Feldmann, newly-appointed vice-president and general manager of 777X development for Boeing.
The 777X is expected to compete with the Airbus A350-900 and A350-1000 over a wide span of the market, stretching from about 330 seats to more than 400, and offering ultra-long-range.
The GE9X offered "the best match to the development programme, schedule and airplane performance", Feldmann says,
GE has designed the GE9X to feature the highest level of fuel efficiency ever achieved by a gas turbine engine. It is raising the overall pressure ratio (OPR) inside the core, a key measure of an engine's thermal efficiency, to 61:1, or 50% higher than the levels reached by the 20-year-old GE90 engine family flying on 777s today.
The 11-stage high-pressure compressor (HPC) boasts a "very high" pressure ratio of 27:1, about 17% greater than current-generation engines.
The increase in pressure ratios allow GE to claim about half of a 10% fuel burn reduction target, when compared to the GE90. The other half of the improvement comes from increasing the fan diameter to 132.5in (3.37m), or 3.5in wider than the GE90, and using the three-dimensional fan blades introduced by the GEnx turbofan family.
The GE9X also will receive the third generation of GE's twin annular premixing swirler (TAPS) technology in the combustor, which improves efficiency while reducing emissions substantially below future targets by regulators.
Advanced materials are now a feature in all new engines, and GE9X will use ceramic matrix composites (CMCs) to include the high pressure turbine shroud. GE is confirms that CMCs will be integrated inside the combustion chamber and the high pressure turbine blades.
GE plans to test a high pressure compressor rig at the company's oil and gas facility in Italy.