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Boeing putting 787 on a diet

 - December 11, 2006, 8:36 AM

Boeing presented a series of planned improvements to the design of the 787 Dreamliner during two days of program updates issued in Seattle last week to airlines, financial institutions and supplier partners. Now Boeing just has to find a way to shed a few thousand pounds from the design to turn its vision for even more range, payload capacity and cabin space into reality.

The improvements include a one-inch increase in cabin width by eliminating a sidewall insulation blanket and an increase in the 787-9’s maximum takeoff weight from 509,000 to 540,000 pounds. That would allow the 787-9 to fly even farther than the standard 787-8, whose range would fall between 8,000 and 8,500 nm. Boeing now lists the 787-9’s range at between 8,600 and 8,800 nm, and the 787-3 at between 3,000 and 3,500 nm. Boeing has also changed the way it identifies passenger capacity, expressing it in seat ranges rather than precise numbers.  

According to Boeing’s latest figures, the 787-8, due for certification in 2008, would carry between 210 and 250; the 787-9 would hold between 250 and 290; and the 787-3 would transport 290 to 330. The numbers reflect a roughly 30-seat increase in capacity across the 787 line.

However, Boeing still faces significant hurdles involving weight. According to the company, the design now weighs roughly 1.5 percent more than its targeted 222,000 pounds. By October various design changes had bloated the airplane by 5,800 pounds. Since then engineers have managed to shave some 2,500 pounds, and, according to Boeing, plan to meet the target “in the coming months.”

“In point of fact, there have not been any major items but as is typical on both sides [gaining and losing weight] we are seeing minor changes–ranging from adjusting thickness on composite plies to adjusting specific designs–that add small amounts or delete small amounts [of weight],” a Boeing spokesperson told Aviation International News. “In either case, several weeks ago and today, we are well within the range of experience for Boeing on previous airplanes. We’ve had airplanes that were similar or even more overweight at this phase that came in at or below target in time for deliveries.”