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Post by aerofoto - HJG Admin on May 16, 2006 21:18:09 GMT
Actually .... I've seen similar sort of fuselage flex on older B747-200 versions when crossing the Tasman through patches of real rough air Seated w-a-y d-o-w-n t-h-e b-a-c-k it's actually quite intriguing looking down the length of the cabin and watching the fuselage flex inwards slightly and overhead side bins respond moving up and down slightly in response to turbulence .... but .... only in some pretty extreme conditions though ! Mark C AKL/NZ
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Post by chris on May 16, 2006 21:49:35 GMT
I think the most fuselage flexing and twisting I've seen was an Airbus, sitting in the back (A320=bad, A340=twice as long=twice as bad). And that was with only moderate turbulence. The scariest thing I've seen was when I was on a flight in very rough weather on a DC-10. I had a window seat looking out at the #3 engine. I thought it was going to get torn off the wing it was moving around so much!
Chris
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Post by christrott on May 16, 2006 22:24:55 GMT
Yes, but with the DC-10, the flex of the engine and wing is good. With the A320 and A340, it's VERY BAD to see much flex in the fuselage and with the A320, any significant wingflex is even worse. Airbus doesn't seem to get the idea of a flexible aircraft like Douglas, Boeing, and Lockheed do. They think that keeping as much of the plane as stiff as possible will reduce wear. Good thing the other guys have a lot more experience in building large airplanes...
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Post by chris on May 17, 2006 1:07:04 GMT
Not to badmouth Airbus, but they just aren't built/designed to last forever like the 707/DC-8 were, so I expect some flex from the lighter construction. After having seen Boeing aircraft up close, seeing the A320's structure was quite interesting in comparison.
I do know the DC-10 wings/engines are supposed to move around quite a bit, but that particular experience happened not long after the AA DC-10 crash, where the engine parted company with the aircraft due to improper maintenance practices, so I was a bit on edge...
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Post by Dee Waldron - HJG on May 25, 2006 8:39:27 GMT
Ahhh.... so for your homework tonight, all you wanna-bee engineers need to lookup and study the two different aircraft construction methods: 1. Fail safe 2. Safe life What is what? And who uses which? Test tomorrow! Cheers!
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Post by chris on May 25, 2006 19:11:08 GMT
Boeing generally uses fail-safe engineering when designing their planes. Any one part can fail and the surrounding structure is designed to take that extra load. Extreme case in point: The Hawaiian 737 "convertible" where the roof blew off.
Not sure what Airbus calls their method, or if it is safe life or not, as I just don't know. What I do know is the structure is generally lighter, but all the structure is designed to work together and be "as one" so as to carry the load by spreading it out more. In a 737, etc, for instance, the cargo pit wall panels are just big fiberglass sheets, and are there for fire containment, and serve no structural purpose in any way. On an A320, the cargo pit wall panels are structural, and any damage to them must be addressed as such.
I agree with Nick in that the Airbus (my experience is limited to A319/A320) is easier to work on than a lot of other aircraft. The 737 is one of the worst, not only because of its small size, but also because the design itself has a couple booby traps built-in. Boeing came a long way when they made the 777. Very mechanic-friendly compared to all of the earlier aircraft.
Chris
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