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Aviation History
2003
2003 - 1104.PDF
GE is introduction of compressor bore cooling working on through the use of a vortex spoiler, improving improved vane materials for greater temper- the -8E's ature tolerance, and a new HP turbine rotor specific fuel for enhanced durability. This last change consumption included making the forward shaft integral following with the stage one HP turbine disc, and was shortfalls accompanied by structurally thickening the revealed web material itself. during The design also included improved cool- 170 flight ing air delivery to the turbine blades and tests helped meet collective -8 growth require ments for a 5% rise in APR thrust, up to a 10% increase in normal take-off thrust and a 14% boost in climb thrust over the -8C1. With three applications looming, GE picked up the pace of the -8 growth pro gramme. HP compressor rig tests began in October 2000, and assembly and instru mentation of the first complete test engine (minus definitive compressor and turbine changes) were completed the next month. Propulsion tests By January 2001, the first propulsion system was on test at GE's Lynn, Massachusetts, site, and ground tests had just begun at Peebles, Ohio, on the first engine due to be tested on GE's Boeing 747 flying testbed. This engine finally took to the air in April 2001 bolted beneath the port wing of the 747 at Mojave, California. Tests of the engine with the full-up compressor and turbine modifications began in July 2001, with US Federal Aviation Administration certification achieved for the whole -8 growth programme in April, 2002. Initial -8E flight test engines were shipped to Embraer in 2001 in preparation for the first flight of the 170 in February 2002. To pave the way for the integration of the engine and to keep pace with the Brazilian company's record-setting sched ule, GE committed a full-time team to Embraer's San Jose dos Campos-based joint definition phase. "It was Embraer's plan to have all the suppliers in the same room, and to have everything in their digital mock-up language," says Blankenship. "We had to hit the ground running at their location with the people we needed. It was a challenge to keep up at first. We had a new aircraft, a substantially new engine and a new customer, all at once." The -8E effort dovetailed with the wider- scale development of the -8 growth family, a certification process that would eventu ally include 19 major engine tests at Peebles, Lynn and at the Japanese test site of Ishikawajima Harima Heavy Industries (IHI), a revenue-sharing partner in the pro gramme. Specific tests for the -8E were also conducted in conjunction with nacelle and reverser supplier MHD - a joint venture between Aermacchi and Hurel Hispano (formerly Hurel Dubois). Aermacchi is responsible for the inlet, fan cowl and sev eral engine build-up units, while Hurel Hispano developed the aft fan cowl and neatly devised thrust reverser. With most 170 flight tests completed, the GE-Embraer team is focused on devel oping the -8E-powered 175 regional jet, as well as the smooth service entry of the 170 in September. In support of the longer- term goals of Embraer, GE is also develop ing a performance improvement package (PIP) for the -8E to overcome specific fuel consumption (SFC) challenges discovered during test flights on the 170. "We're talk ing about picking up 0.3% here and another 0.2% there," says Blankenship, who plays down the shortfall. "It is not a major situation - we just need to tighten up the configuration." Improvement option Although no significant hardware or soft ware changes are envisaged, the PIP will focus on improved cooling and tighter clearances. One SFC improvement option considered for the PIP, but rejected, was the replacement of the -8E's noise-reducing chevron nozzle with a more conventional conical exhaust. "However, it turns out the configuration needs the chevrons for noise reasons," says Blankenship. GE is set to deliver the first 175 flight-test engines in the third quarter, and is develop ing the next CF34 variant, the -10E for the stretched Embraer 190. The -10E is rated at around 18,5001b thrust (82.5kN) and incor porates a 3D aerodynamically designed HP compressor, a low-emissions single annular combustor that cuts nitrous oxide emis sions by up to 12% compared with a cur rent unit, and a low parts count HP turbine. The -10, also selected for the China Aviation Industry I ARJ21 regional jet, will also sport chevrons. Development work on the ARJ21 variant has begun. • 64 13-19 MAY 2003 FLIGHT INTERNATIONAL www.fliqhtinternational.com
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