The General Electric GE90 is a family of high-bypass turbofan aircraft engines built by GE Aviation for the Boeing 777, with thrust ratings from . It entered service with British Airways in November 1995. It is one of three options for the 777-200, -200ER, and -300 versions, and the exclusive engine of the -200LR, -300ER, and 777F. It was the largest jet engine, until being surpassed in January 2020 by its successor, the GE9X, which has a larger diameter fan. However, the GE90-115B, the most recent variant, is rated for a higher thrust (115,000 lbs) than the GE9X (105,000 lbs).
Development
The GE90 was developed from the NASA 1970s Energy Efficient Engine, a prototype variant of the General Electric CF6. GE's GE36 Un-Ducted Fan (propfan) was meant to replace the CFM International CFM56 high-bypass turbofan which was initially uncompetitive against the rival IAE V2500. However, when the V2500 ran into technical problems, sales of the CFM56 took off. GE was not interested in having the GE36 cannibalize the CFM56, and while "the UDF could be made reliable by earlier standards, turbofans were getting much, much better than that." However, GE integrated the UDF's blade technology directly into the GE90.
The GE90 engine was launched in 1990. GE Aviation teamed with Snecma (France, 24%), IHI (Japan) and Avio (Italy) for the program. Initially the GE90 was only one of three 777 options and GE Aviation then-CEO Brian H. Rowe would have paid for the development of putting it on an A330, but Airbus' strategy for long-haul was the four-engine A340, missing the market favouring twins.
The bigger and higher-thrust -115B version that powers the second generation 777 (-300ER, -200LR, and -200F) had its first run at the GE facility in Peebles, Ohio in November 2001.
Design
The GE90's 10-stage high-pressure compressor developed a then-industry record pressure ratio of 23:1 and is driven by a 2-stage, air-cooled, HP turbine. A 3-stage low-pressure compressor, situated directly behind the fan, supercharges the core. The fan/LPC is driven by a 6-stage low-pressure turbine.
The higher-thrust variants, GE90-110B1 and -115B, have a different architecture from that of the earlier GE90 versions. General Electric incorporated an advanced larger diameter fan made from composite materials which enhanced thrust at low flight speeds. However, GE also needed to increase core power to improve net thrust at high flight speeds. Consequently, GE elected to increase core capacity, which they achieved by removing one stage from the rear of the HP compressor and adding an additional stage to the LP compressor, which more than compensated for the reduction in HP compressor pressure ratio, resulting in a net increase in core mass flow . The higher-thrust GE90 variants are the first production engines to feature swept rotor blades. The nacelle has a maximum diameter of . Each of the 22 fan blades on the GE90-115B have a length of and a mass of less than .
Operational history
As one of the three available engines for the new Boeing 777 long-range airliner, the GE90 was an all-new $2 billion design in contrast to the offerings from Pratt & Whitney and Rolls-Royce which were modifications of existing engines.
The first General Electric-powered Boeing 777 was delivered to British Airways on November 12, 1995. The aircraft, with two GE90-77Bs, entered service five days later. Initial service was affected by gearbox bearing wear concerns, which caused the airline to temporarily withdraw its 777 fleet from transatlantic service in 1997. British Airways' aircraft returned to full service later that year.
Problems with GE90 development and testing caused delays in Federal Aviation Administration certification. In addition the GE90's increased thrust was not yet required by airlines and it was also the heaviest engine of the three available choices, making it the least popular option while the Rolls-Royce engine was the most popular. British Airways soon replaced the GE90 with Rolls-Royce engines on their 777s.
For Boeing's second-generation 777 long-range versions (later named 777-200LR, 777-300ER, and 777F), greater thrust was needed to meet the aircraft requirements. General Electric and Pratt & Whitney insisted on a winner-take-all contract due to the $500 million investment in engine modifications needed to meet the requirements. GE received sole engine supplier status for the higher-thrust engine variants for the 777-200LR, -300ER, and 777F. The improved version entered service with Air France in May 2004.