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Aviation History
1990
1990 - 0151.PDF
TECHNICAL: PROPULSION GE joins fight for worid's largest turbofan BY JULIAN MOXON IN WASHINGTON DC General Electric (GE) Aircraft Engines last week unveiled the most powerful turbofan it has ever developed—the 34,100- 43,200kg (75,000-95,0001b)- thrustGE90. Aimed initially at the still-to- be-launched Boeing 777 and other new widebody twins, the GE90 kicks off a family of very- high-bypass-ratio engines that will eventually span the entire 25,000-43,180kg (55,000- 95,0001b)-thrust range. Certification of the first 36,360kg (80,0001b)-thrust ver sion of the GE90 is set for May 1994, with delivery of engines beginning about a year later. This sets a challenging schedule for what is virtually a new engine— albeit based on years of research, plus technology from the current CF6-80C2/E1 and CFM56 engines. "There's a tremendous market out there," says GE Aircraft En gines chief Brian Rowe. "We think the potential is for sales of 2,500 aircraft up to the year 2010. That's 6,000 engines, including spares." Rowe puts GE90 development cost at between $1.2 billion and $2 billion. "It means a pretty big front-end investment," he adds, GE90/CF6-80C2 comparison 1 2 3 4 b QCSEE (quiet clean shorthaul experimental engine) composite cowl QCSEE composite trans cowl and inner cowl QCSEE load sharing nacelle CT7/F110 alt disks and casings CF6-80E airfoiis and disks 6 CF6/CFM56/F110 airfoils 7 GE36/CFM56 composite wide chord fan blades 8 Ensealed compressor 9 F404/E3 dual dome muHi-fioteeooleef combuster 10 CF6-80C2 34'sloped turbine "but at $10 million each, we're looking at well over $50 billion- worth of business." Referring to high-thrust engines under development by Rolls-Royce and Pratt & Whitney, Rowe added "there is no question we expect competition for it." Risk-sharing partners will in clude Snecma—GE's partner in EFA awards new engine contracts Eurofighter has awarded the contract for the European Fighter Aircraft's (EFA) auxiliary power unit to a team consisting of Alfa Romeo Avio, Normalair- Garrett, Industria Seviliana de Automotion (ISA) and Garrett. Alfa will build the compressor and combustor, NGL the elec tronic control unit, ISA the gear box and Garrett will make the power section. The initial development contract is worth $45 million and the potential value of the entire development and production programme is set at some $150 million. • Lucas Aerospace has con firmed EFA engine system con tracts initially worth almost $56.4 million and potentially worth'more than $330 million. Lucas is contracting to Rolls- Royce for the main engine fuel pumping unit, afterburner centrifugal pump and the after burner fuel metering unit. On the main engine pumping unit Lucas is working with Pierburg Luftfahrtgerate Union (PLU) of West Germany, and Secondo Mona of Italy on the afterburner pumping unit. On the main fuel metering unit CESA of Spain joins the trio, and for the after burner metering unit Lucas teams with Mannesmann Rex- roth of West Germany, Seconda Mona and CESA. A fourth contract, for the main engine fuel metering unit, has been won by Sener of Spain. • *he CF6 and CFM56—"and potentially MTU", which may design the low-pressure turbine. GE is also talking to an unspeci fied Japanese company (thought to be Ishikawajima-Harima Heavy Industries) about partner ship. Volvo and Fiat are expected to be non-risk-sharing associates in the programme. Snecma will be a major partner with a 25% stake in the pro gramme, according to Snecma chief executive Louis Gallois. The French manufacturer will have, responsibility for the high- pressure compressor and booster as well as development work on the backup titanium fan. Snecma will also develop the- ten-stage compressor contributing to the engine's expected high overall pressure ratio cycle. The HP turbine will feature single-crystal blades, and the tur bine discs are of boltless design with smooth side plates. N. The GE90 features an all-new, 40:1 -pressure-ratio, ten-stage.gas generator, scaled up from the advanced core developed in its energy-efficient engine pro gramme. "We felt we needed a gas generator change," says Rowe. "This gave us a good opportunity to do it." Another major change comes with the introduction of a 304cm-diameter, all-composite wide-chord fan, giving the GE90 a 10:1 bypass ratio—about double that seen in today's turbo- fans—and contributing towards a 10% reduction in specific fuel burn. A titanium backup fan will be developed in parallel, how ever, just in case GE runs into development problems with the composite design. Also new is the all-composite load-bearing nacelle, which will form an integrated part of the propulsion system, remaining on the wing if necessary while the core and fan assembly are re moved for maintenance. GE90 development so far covers "several hundred" hours of compressor tests, which, says Rowe, "have shown us the pres sure ratio and efficiency we want". Birdstrike tests have been run also with simulated fan blades. "The GE90 has a lower tip speed than previous engines," says Rowe, "which means that its resistance to birdstrikes will be better". First run of a complete engine is due in the first half of 1991, says GE. D PI inHTlNITFPNATIDNAl 74-T.O To 17
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