Guy Norris/SINGAPORE
BRITISH AIRWAYS, Lufthansa and Singapore Airlines are close to negotiating launch orders with Boeing for the 747-600X, the stretched version of the present 747-400 and the first major derivative of the 747.
The airlines will meet Boeing in early April at a crucial meeting of a customer-led 14-strong advisory group. Boeing hopes that the meeting, the first of at least three planned for 1996, will help define the requirements and configuration of the derivatives, which it plans to launch in quick succession.
The -600X is expected to be launched around December, followed within six months by the -500X, a 420- to 450-passenger successor to the -400.
"It's really just one programme from an engineering standpoint," says Boeing vice-president for product strategy, Borge Boeskov. Key to the development is a new, 74m-span, wing. "It's like a 777 wing scaled up by around 30%," says Boeskov. The wing will be structurally similar to that of the twinjet and will not require heavy strengthening, as wing bending-relief will be provided by the outboard engines. The larger chord of the new wing, around 1m greater than that of the current wing, is mainly responsible for the slight increase in length of the -500X over the -400.
One of the last major-configuration question marks hangs over the engines. Boeing is anxious to avoid the introduction of new types and has looked closely at the General Electric CF6-80E1, Pratt & Whitney PW4168 and Rolls-Royce Trent 700, already launched on the Airbus A330. "Performance and noise are the main drivers," Boeskov says.
The 777 engines, with the exception of the smaller-fan-diameter Trent 800, are believed to be too large, in both physical size and power. Engine makers are looking at various solutions. GE is studying a CF6-80X, and P&W is examining a modular powerplant based on the PW4000 family, while R-R is considering a modified Trent 700 or a de-rated Trent 800.
The -500X is expected to have a maximum gross take-off weight (MGTOW) of between 590,000kg and 680,000kg, with a range of 15,000-15,700km (8,200-8,500nm). With the shorter range of the -600X, at around 13,300km, Boeing has traded fuel for weight and will have a similar MGTOW.
Source: Flight International
