General Electric is finalising development plans for a 17,000-18,000lb-thrust (75.6 -80kN) growth derivative of the CF34-8D, dubbed the -8XX, for Fairchild's 928JET programme.
The engine is expected to make its first test flight in mid-2003, and could be certificated by the US Federal Aviation Administration as early as the fourth quarter of that year, says the manufacturer. "It will have a similar core to the other -8C/D derivatives, but with a new fan and low-pressure system," says GE Small Engines manager, Frank Klaus. The new low-pressure system, with three stages, will be attached to a 1.34m-diameter fan and a scaled-up, four-stage low-pressure turbine section.
The -8X development plans have begun to harden following the recent launch of the -8D3 version for the 728JET. The first full engine tests of the -8D3 version are due to begin in June 2000, with first flight of the 728JET expected in the first quarter of 2001. FAA certification of the engine is scheduled for September 2001.
Meanwhile, GE expects to finish flight tests of the CF34-8C1 turbofan for Bombardier's CRJ700 by the end of the month, following the completion of the bulk of the programme aboard GE's 747 testbed (above). Results in most areas are "better than expected" says GE, although damage to inner flow path noise supression panels during hail ingestion tests has posed questions over the possible need to strengthen the inlet lining. "We've been pleasantly surprised at some things," says Klaus. "One of the things we were concerned about was the air start envelope, because the core is somewhat hidden, but this has not been an issue. Cruise specific fuel consumption has come out between 1% and 1.5% better than we expected," he adds.
Significant tests remain, including large bird ingestion and fan blade-off. Klaus believes, however, that the earlier modifications made to the fan containment system will enable the engine to pass the critical tests. First flight of the CF34-8C1- powered CRJ700 is expected around the end of this month, marking the start of a 16-month certification, expected to culminate with certification and initial deliveries late next year.
Source: Flight International
