Design teams from Fairchild Aerospace, General Electric, Hurel Dubois and Aermacchi are expected to begin the first formal meetings on the design of the powerplant for the 728JET this week, following the selection on 3 August of the General Electric CF34-8D.
Although the -8D has 100% commonality in terms of turbomachinery with the -8C1 under development for Bombardier's Canadair CRJ-700 regional jet, the interfaces, engine build-up units (EBUs), nacelle and support structure will be different for the underwing installation.
"We have to get the interface designed and to market as quickly as possible," says Frank Klaus, general manager of GE's small commercial turbofan department.
The regional jet development timescale has slipped because of prolonged debate over design requirements with launch customers Lufthansa CityLine (which favoured the GE engine) and Crossair, and the recent appointment of John Wolf as chief operating officer. "We have some headwind to make up," says Klaus.
The newest aspect of the powerplant effort is a teaming arrangement between Hurel Dubois and Aermacchi on the nacelle and thrust reverser. Hurel Dubois will have responsibility for the reverser and will share development of the remaining nacelle and EBUs with Aermacchi, which will be prime contractor on the inlet. The new team shares the effort 50:50 and is arranged along the lines of CFM International, says GE. The current -8C1 nacelle supplier is Shorts, which was effectively eliminated from the bidding because of its Bombardier ownership.
Part of the reason for GE's selection over strong competition from the proposed Snecma/Pratt & Whitney Canada SPW14, was "low risk", says Klaus. Another was GE's commitment to develop engines for the planned members of the Fairchild family, including the 50/63-seat 528JET and the 80/98-seat 928JET. The 528 will be powered by a derated version of the -8D, says Klaus. The 928JET, which is "still the least defined of the three aircraft", is expected to require 10% higher thrust than does the 728, which will have two 62kN (14,000lb)-thrust -8Ds. "We committed to 10% higher thrust," he says. GE has agreed to raise thrust levels higher, if needed.
First -8D testing is planned for the fourth quarter of 1999, with the first flight of the 728JET due around the first quarter of 2000. US certification of the engine is targeted for the first quarter of 2001.
Under current plans, the certification of the 528JET follows that of the 728 by 18 months, with the 928JET following 18 months behind that.
Source: Flight International
