Assembly of engine for Airbus and Boeing 787 to begin in October, with first test due in March 2006
General Electric has begun manufacture of the first GEnx engine being developed for the Boeing 787 and Airbus A350, after freezing the detailed design that includes a front fan with only 18 blades.
Details of the final configuration were approved for the release of hardware and the start of manufacturing at a "Toll Gate 6" meeting at Evendale, Ohio. Assembly of the first GEnx engine is scheduled to start in October, with first engine to test in March 2006. Tests on GE's 747-100 flying testbed (FTB) are set for the third quarter of 2006, with first flight on the 787 expected about a year later.
Up to 10 test engines have been assigned to the certification programme. Seven are for the initial bleedless Boeing application covering three variants – the GEnx-54B for the 787-3, the -64B for the 787-8 and the -70B for the 787-9. Three are for the bleed-enabled -72A1 version for the A350-800/900.
As some design details remain to be ironed out for the Airbus engine, and entry into service of the A350 is some two years later than that of the 787 in mid-2010, GE says the equivalent Toll Gate 6 milestone is not scheduled until late January 2006.
The first Airbus GEnx-72A1 engine will make its initial run in the third quarter of 2007, with flight tests on the 747 FTB in the second quarter of 2008. GE hopes for a relatively speedy certification effort, given the preceding 787 engine programme, and hopes for US Federal Aviation Administration FAR 36 engine clearance by early in the fourth quarter of 2008.
First flight on the A350 is provisionally expected in the third quarter of 2009, with entry into service around mid-2010. "It's execution time," says GE commercial marketing general manager Mike Wilking. "We're cutting metal on all components and working the build process. We are even looking at ways to build them differently."
The decision to go to 18 blades, compared with 22 in the fan of the GE90, was driven by the need for better efficiency, lower weight and reduced noise. "Having just 18 blades cuts the scrubbing losses [aerodynamic interaction with the wake of the preceding blade], cuts weight and improves noise reduction," says Wilking. Scaled rig tests will continue.
"We are also looking at the potential of taking some more weight out of the case," he adds. Fan diameter, meanwhile, remains locked in at 2.82m (111in). Despite the extensive use of composites, which saved about 160kg (350lb) on the fan case alone, GE acknowledges the engine is still likely to be a "bit heavier" than the competing Rolls-Royce Trent 1000.
Engine configuration includes a four-stage low-pressure (LP) compressor, 10-stage high-pressure (HP) compressor, two-stage HP turbine and seven-stage LP turbine.
GUY NORRIS/LOS ANGELES
Source: Flight International
