World’s largest jet engine is getting ready to power the Boeing 777X
GE Aviation, an operating unit of General Electric (GE), is building the GE9X exclusively for the newest version of Boeing’s long-haul airliner the 777X. Launched in 2013, the GE9X programme has recently passed key milestones in its extensive testing campaign and is on track to propel the 777X for its maiden flight.
Boeing revealed that it had completed the first 777X ground test airplane in October 2018. At the time, the first flight test plane had also received its new CFRP (Carbon Fibre Reinforced Polymer) wings and now, it appears that the GE9X engines have been installed on that 777X prototype.
The plane, which has been housed in Boeing’s Everett, Washington assembly plant, is set to roll out in February 2019 and its first test flight is expected to take place later this year.The first delivery of the 777X, the 777-9 variant is scheduled to enter service in 2020 with launch customer Emirates. GE states it has orders for 700 GE9X engines so far, with customers including Qatar Airways, ANA and Singapore Airlines. When it enters service with the 777X, the GE9X, roughly the size of a 737’s fuselage, will be the largest commercial jet engine available.
The first full GE9X developmental engine was fired up for the first time in March 2016, beginning ground testing at GE Aviation’s Peebles Testing Operation (PTO) in Ohio, US, just six months after the engine design was finalised. Certification testing commenced in May 2017, marked by the firing up of the second GE9X production-configured power plant at the PTO site. A year later, in March 2018, the GE9X was taken airborne for its first flight test under the wing of GE Aviation’s 747-400 flying test bed in Victorville, California. Other completed tests included crosswind operability, high-pressure turbine stress, icing, emissions and water ingestion. With a total of eight engines involved in the certification programme, GE states it now hopes to meet a 2019 target date for safety certification, later than initially hoped.
According to GE, the GE9X engine will be the most fuel-efficient jet engine the company has ever produced on a per-pounds-of-thrust basis. The GE9X has been developed on the foundations of the GE90 (it is the fifth evolution of the GE90). That engine, developed back in the early 1990s, powers the Boeing 777. Although the GE9X is the largest engine in the world, it is not the most powerful. For instance, today’s GE90-115B, used on the 777-300ER, is the largest of the original GE90 variants, rated for over 115,000 pounds of thrust. To date, the GE90-115B holds the title of the world’s most powerful engine at 127,900 pounds of thrust (originally, the GE90 was designed for a 76,000-pound thrust requirement). The GE9X, meanwhile, classifies in the 100,000 pound thrust category.
Larger engines potentially mean higher fuel consumption and associated costs. However, the manufacturer states that compared with the GE90-115B, the GE9X will be capable of delivering 10% improved fuel burn. It will also have a 5% improved specific fuel consumption compared with any twinaisle engine currently out there. However, what surely stands out the most is that the largest jet engine will have the largest front fan: the power plant will have a composite fan case measuring at over 11 feet (approx. 3.40 metres) in diameter and only 16 fourth generation carbon fibre composite fan blades. The GE9X is designed to achieve an approximate bypass ratio of 10:1 and an overall pressure ratio of 60:1. The power plant features a next-generation 27:1 pressure-ratio 11-stage high-pressure compressor; a third-generation TAPS III (twin-annular pre-mixing swirler) combustor for high efficiency and low emissions; and CMC (ceramic matrix composite) material in the combustor and turbine.