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Aviation History
2000
2000 - 1968.PDF
ENQINE* GRAHAM WARWICK/WASHINGTON DC THE ENGINE that launched the regional jet age is powering die next phase of die RJ revolution. Already die leading power-plant in the 50-seat jet market, General Electric's CF34 is to power all major contenders in die 70- and 90-seat markets. While the CF34-3 powers the 50-seat Bombardier CRJ100/200, the uprated -8 is under development for the stretched 70-seat CRJ700 and 90-seat CRJ900. The CF34-8 will also power die 70-seat Embraer ERJ-170 and Fairchild Dornier 728JET, while the -10 growth derivative has been selected for die 90- seat ERJ-190 and 92 8JET. Covering a thrust range from 8,7501b to 18,5001b (38.9-82.3kN) is no mean feat for an engine, but in the CF34's case it involves stretching die definition of a derivative. "The CF34-10 is a new centreline engine," admits Frank Klaus, general manager of GE's small commercial engines operation. "But, from a customer's viewpoint, the accessories are die same as die -8. They are in die same place, for quick removal and replacement." The CF34-8 is, itself, substantially different from the baseline -3. Thrust is increased by 50%, to 14,0001b, and parts count is reduced by 30% - largely due to die use of a high-pressure (HP) compressor derived from that in GE's F414 fighter engine, with 10 stages instead of die -3 's 14. Specific fuel consumption, noise and emissions are all reduced from -3 levels. The -8 also introduces full-authority digital engine control (EADEC) to the CF34. The -8 programme is on track, says Klaus. The -8C1 for die CRJ700 was certificated in The uprated CF34-8 is under development to power the CRJ900 November last year and Bombardier has select ed die 5%-uprated -8C5 to power die yet-to- be-launched CRJ900. Ground testing of the -8C5 has begun and certification is planned for die second quarter of 2002. "It's a very aggres sive schedule," says Klaus. The first wing-mounted versions of the CF34 - the -8D for the 728JET and the -8E for the ERJ-170 - are also progressing. Ground • testing of bodi versions begins in die diird quar ter. The -8E is uprated by 5% from die -8D, which shares die turbomachinery, accessories and FAD EC of die -8C. The major difference is die nacelle: die wing-mounted unit for die -8D/E is produced by Aermacchi and Hurel- Dubois, while die fuselage-mounted nacelle for die -8C is produced by Bombardier's Shorts. GE is introducing its "chevron" nozzle on die -8D/E and is speaking to Bombardier about fit- losophy of using proven, derivative technology. GE has completed conceptual design of die -10 and will begin detail design by mid-year. Klaus says two main drivers guided die initial design: die need for a core large enough to pro vide die take-off dirust margins that will be required to meet increased range and payload targets, and die desire to assure low-risk, low- cost development. The resulting design draws on technology from a range of GE engines: from the CF6, die retention system for die wide-chord fan blades and die composite swept and "leaned" fan out let guide vanes; from the CFM56, die diree- dimensional HP compressor aerodyamics, single annular combustor and single-stage HP turbine; and from die CF34-8, die four-stage HP turbine and FADEC. The first engine to test is planned for die first I Covering a thrust range from 8,150lb to 18,5001b (38.9-82.3kN) is no mean feat for an engine ting die noise-reducing device on die -8C. The companies are also talking about standardising on the -8C5 for both the CRJ700 and CRJ900. The -8C5 uses die uprated turbomachinery of die -8E, and would be derated to power die 70- seat CRJ700, offering maintenance benefits. Selection of the -8C5 to power the CRJ900 gets the engine into die 90-seat regional jet market, but die CF34-10 represents a "dramat ic move forward", says Klaus. The need for 30% more growth in dirust, to 18,5001b with the potential for 20,0001b, has resulted in an essen tially new engine which follows die CF34 phi- quarter of 2002 and the -10 is set to fly on GE's Boeing 747 engine testbed in mid-2002. Certification is set for early 2003. The first air craft to be powered by die -10 will be Embraer's 110-seat ERJ-190-200. GE, meanwhile, is not neglecting the CF34- 3. Durability and repairability improvements will be introduced into production engines in die third quarter, with upgrade kits for in-ser vice engines available in the fourth quarter. These are expected to increase time "on wing" by 30%, says Klaus, and will keep the CF34 at die front of die regional jet revolution. • FLIGHT INTERNATIONAL 27 June - 3 July 2000 39
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