Guy Norris/SEATTLE
Flight tests of blended winglets on a 737-800 have started so that performance benefits from eventual incorporation on the Boeing Business Jet (BBJ) can be evaluated.
The tests are part of Boeing's efforts to stretch the BBJ's range by around 5% beyond the current 11,100km (6,000nm) capability in response to customer input. "We're right on the edge of being able to fly from New York to Tokyo," says BBJ president Borge Boeskov, who adds that achieving this target "-depends on tests that we are doing right now".
Initial flight tests began on 28 May, with the 2.6m-tall winglets installed on the prototype 737-800. Boeing considers this to be fairly representative of the BBJ, which is a hybrid of the 737-700 fuselage and -800 wing, engines and gear. "The aircraft handles well with these things on," says Boeskov, who adds that "-we have to do more tests over the next 30 days and, within two months, we will decide on whether to use them". The blended winglets, designed and produced by Seattle-based Aviation Partners, weigh about 180kg (400lb) per shipset.
With 14h of flight tests completed and initial flutter clearance achieved, Aviation Partners chief executive Joe Clark is optimistic that the winglets will be adopted. "The numbers are shocking everybody. We guaranteed Gulfstream 5% [lower fuel consumptionand greater range]. Their owners are saying they are getting more, and we expect Boeing to get similar results," he says. Clark, whose company provides similar winglets for the Gulfstream II and III, says that the equipment should improve the BBJ's cruise altitude by up to 1,500ft (460m) at the same weights.
The first BBJ fuselage began its rail journey from Boeing's Wichita site in Kansas to Seattle on 1 June. The aircraft will be "joined" at Renton in the third week of June and will roll out on 19 July, says Boeskov. "We plan to fly it for the first time on 17 August," he adds. Meanwhile, Boeing is expected to announce further sales to extend the orderbook beyond the current 29. No firm numbers have been given, but Boeskov says that new orders will be announced as part of a fractional ownership deal with Executive Jet International.
Source: Flight International
