Guy Norris/LOS ANGELES
McDONNELL DOUGLAS (MDC) hopes to begin offering its MD-XX, the MD-11 tri-jet derivative, to airlines as early as October and "-will launch as soon as possible after that, probably in early 1997", says Walt Orlowski, MDC vice-president and general manager of the programme.
The MD-XX and the long-range MD-XXLR will be launched simultaneously, although development of the MD-XX will run about six months ahead that of the MD-11-sized MD-XXLR. Targeted first delivery of the MD-XX is December 2000. MD-11 production, increasingly led by freighter derivatives, will continue through the development phase after 2001.
MDC's Douglas Aircraft division (DAC) plans to protect the development timescale of the long-range MD-XX for as long as possible. "We can defer a decision on the second aircraft until quite late," says Orlowski. "Customer interest is evenly split. We have letters of interest for both [six airlines for 40 aircraft]," says engineering vice-president Allen Haggerty.
Previously unreleased data from DAC reveal that the common wing will be 485m2 (5,200ft2) in area, 40% larger than the present MD-11 wing. It will have a wider (65m) span, with winglets, making it similar to that of the Boeing 747-400, to take advantage of existing airport infrastructure. The supercritical wing design is optimised for a cruise speed of Mach 0.85, about M0.03 faster than for the MD-11. The new wing has a larger buffet boundary with an initial cruise-altitude of 35,000ft (10,600m) at M0.85, compared with 31,000ft and M0.82 for the MD-11.
"The wing is the best we can do by taking the resources of the entire MDC company," says Orlowski. "A lot of high-lift technology, including Fowler flaps and full-span leading-edge devices have been introduced to slow down the aircraft by up to 13kt [25km/h] on approach," he adds.
This will allow the MD-XX to carry 20% more payload from runways similar to those used by present tri-jets, while the MD-XXLR will have 20% more range. Maximum gross take-off weight will be similar for both versions, at around 363,800kg.
The MD-XXLR fuselage will be based on that of the stretched MD-XX, which will be built first. This will be 71.2m long, just under 1m longer than that of the 747, and around 9.7m longer than the MD-11's, with seating for 375 in three classes. The LR, seating 309, will be produced by removing 4.9m from forward of the wing, and 4.5m from aft of the wing.
DAC plans to narrow the engine choice to two before launching the programme. Derivatives of the General Electric CF6-80E1, Pratt & Whitney PW4168 and Rolls-Royce Trent 772 are on offer.
Source: Flight International
