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Engineers on the project say wing design flaw will prevent test flight in 2009

Boeing's 787 “Dreamliner” has been more of a nightmare for many at Boeing as the project has cost significantly more than expected and is still two-years late (and counting).

Another problem in the 787's design has been found, this time in the wings. During tests to certify the aircraft, damage to the wings and wing box of the 787 was found. The damage was delamination of the composite sheets covering the wings under stress.

The Seattle Times reports that the structural flaw in the Dreamliner was discovered in May during ground tests that bent the wings upwards to simulate stress during flight. The stress at the end of rods used to stiffen the upper wing skin panels caused the composite plastic material used in the wings to delaminate.

The damage to the wing occurred just beyond the Dreamliner's load limit, described as the maximum weight the wing is expected to bear in service. The Seattle Times mistakenly reported last week that the damage occurred just over the wing's ultimate load, which is 50% higher than the in-service limit load the wing is expected to endure. The limit load is the FAA test target and proves that the problem with the design of the wing is worse than originally believed.

The plane could have flown after the wing damage, but the test flights would reportedly have been severely restricted. The damage the wing sustained is reportedly not severe enough to have caused any sort of catastrophic failure had it happened in flight.

The design flaw and time needed to devise and implement repairs on the fleet means that the test flight will not likely happen this year according to one engineer on the project. The test flight was delayed in late 2008 to Q2 2009.

The damage to the wings extends inside the fuselage of the aircraft as well making repairs more difficult. The failure in the wing and the wing box is not the fault of Fuji Heavy Industries, who manufactures the components for Boeing. That means Boeing is solely responsible for any cost overruns and time delays because of the issue.

The fix has yet to be certified but could involve engineers creating a U-shape cutout in the end of the upper wing skin stringer and then refastening the reshaped stringer ends with new titanium fittings.



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RE: Haha ! suck it Boeing
By Belard on 7/31/2009 3:00:03 PM , Rating: 2
No, the 40+ year old 747 isn't obsolete.

The A380 has more limited landing locations than the 747. The price per plane is vastly different.

747 are $225~300million each
380 are $320~350million each

The 747 will continue to be made for many years to come.
The 380 was built to compete with the 747, Boeing won't be making a whole new plane to replace the 747 any time soon. Why bother? It was made 40 years ago and far cheaper... as proven by the problems (typical) of any new airliner.

Unlike the A380 (and Dreamliner), other than a revision/update - there is no R&D costs for the 747, so its very profitable. The 747-8 will use some Dreamliner tech to maker it less noisy and more fuel efficient.


RE: Haha ! suck it Boeing
By gcouriel on 7/31/2009 5:07:20 PM , Rating: 2
well, actually...

the A380 is marketed as a Super Jumbo jet, capable of flying more people, economically, than the 747. the problem with the A380 is that it's SO LARGE, that it doesn't make sense for many carriers to have one. additionally, it requires changes in airport infrastructure, which will limit use. you'll probably see a lot traveling between the US (NY) and London or Paris, as well as long-haul flights out of LAX to Tokyo or some Chinese cities, but for the most part, the 747, a known commodity, will continue to dominate.

However, Boeing isn't sitting on it's ass on this one. coming down the pipeline is the next revision(s) to the 747, namely the 747-8 and 747-9, taking advantage of the technology acquired from the 787, and applying it to the 747, including use of composite materials to lower weight and improve efficiency.

check it out: http://www.boeing.com/commercial/747family/747-8_b...


RE: Haha ! suck it Boeing
By Belard on 7/31/2009 7:21:27 PM , Rating: 2
That is pretty much what I said.


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