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- 06/03/2012, 13:19 #1
Boeing: Piensa en actualizar el 777 (Principalmente con mejoras aerodinámicas)
Boeing is evaluating a series of systems, aerodynamic and interior upgrades to the current 777 family at the same time as it aims for potential board approval by year-end for the advanced 777X derivative.
The improvements, ranging from potential drag reduction features and lighter structures and systems to enhanced interiors, are designed to sharpen the 777’s competitive edge while paving the way for a transition to the more ambitious re-winged, re-engined 777X later this decade. The initiative includes leveraging technology developed for the 787 program as well as studies of the potential for retrofitting some elements into the existing fleet.
Possible aerodynamic upgrades include improved seals and gaps, particularly in the wing leading edge, as well as the use of drag-reducing hybrid laminar flow control (HLFC) technology currently under test for possible application on the 787-9. If adopted, the HLFC would be used only on the leading edge of the vertical fin, says 777 VP and chief project engineer Bob Whittington.
The HLFC system reduces drag by extending the amount of surface area over which the airflow is laminar, or smoother, with a later onset of drag-generating turbulence. Although details of the technology being tested by Boeing remain scarce, the concept is based on a semi-passive suction system which is thought to have few or no moving parts. As it does not require a turbo-compressor, or some other active method to produce suction, it also is believed to be essentially maintenance free. Given indications of the system’s initial success during tests on the 787-8, Whittington says its eventual use is “not a question of if, but when.”
Project engineers also continue to strive for additional weight reductions beyond the 500 lb. already shaved off the 777-300ER since entry-into-service in 2004. The ongoing weight reduction target, to be achieved by a combination of structural optimization, updated systems and other advances, is between 100 and 125 lb. per year, he adds.
The company’s upgrade studies also are mindful of the need to avoid disrupting the production system, currently preparing to accelerate in rate from the current 7 units per month to 8.3 early next year. The “rate break” will officially begin in October ahead of the first delivery at the new level in the first quarter of 2013, or 48 production days later, says 777 Director of Manufacturing Jason Clark. The aircraft “will continue to evolve,” says Clark, adding that the focus is “on things that could buy its way. As we look at those technologies, we make sure we are always evaluating the risks to the production system.”
Details of the upgrade study emerge as Boeing sets its sights on getting board authority by year-end to begin offering the 777X in the market. Speaking after a ceremony marking the handover of the 1,000th 777, a 777-300ER to Emirates Airlines, Boeing Commercial Chief Executive Jim Albaugh said the move would be made assuming both the business case and technical trade studies close. As currently outlined, the 777X family is thought to consist of advanced 777-200LR and -300ER derivatives with extended span, all-composite wings and new-generation turbofans. The two variants in preliminary study are a 350-seat 777-8X and a 410-seat 777-9X with a target entry-into-service around 2019.
Boeing Details Interim Upgrade Studies For 777 | AVIATION WEEK
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