Travellin'man From United States of America, joined May 2001, 530 posts, RR: 0 Reply 1, posted (12 years 2 months 19 hours ago) and read 1691 times:
Not being either a pilot or an aerodynamicist, I can't give you a definitive answer. I can vaguely say that the wings bend during flight as a function of lift. It is very obvious on an A340, where the wing bends upwards on take-off as the plane achieves lift; quite fun to watch.
try on the tech ops page, and I'm sure you can get someone to explain the exact physics of it.
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AJ From Australia, joined Nov 1999, 2380 posts, RR: 26 Reply 3, posted (12 years 2 months 18 hours ago) and read 1670 times:
I have noticed that trailing edge 'bend' near the winglet both on the ground and in the air, so it can't be due to aerodynamic loads. Mr. Boeing must have put it there due to localised airflows I guess.
UTA_flyinghigh From Tunisia, joined Oct 2001, 6495 posts, RR: 51 Reply 4, posted (12 years 2 months 18 hours ago) and read 1661 times:
Wings of the 744 can bend down before a long flight because the wing is fully loaded with fuel, i.e the UA 744 pictured above. Just after takeoff, the tremendous lift provided by the wings causes them to bend upwards, like the QF 744. This is absolutely normal as aircraft wings are designed to be flexible. In fact all large-wingspan aircraft tend to do this
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Mr.BA From Singapore, joined Sep 2000, 3423 posts, RR: 22 Reply 5, posted (12 years 2 months 18 hours ago) and read 1655 times:
I agree the wings bend down because of fuel in the wings... I thought the whole wing would blend up during take-off. But what's amazing to me that I have noticed, the wing blends upwards in flight to provide lift the end of the wing near the winglet, blends down.
But hey, whatever it is, that's a great wing being able to carry tons over miles.
Victor Alpha From , joined Dec 1969, posts, RR: Reply 6, posted (12 years 2 months 13 hours ago) and read 1611 times:
I dont believe that the fuel in the wings causes the area around the wingtip to droop down. Look at the Virgin shot. The area around the winglet droops down yes, but it is on approach, so I would gather that that fuel tank is going to be empty pretty soon.
RAAFController From Australia, joined May 2001, 125 posts, RR: 0 Reply 7, posted (12 years 2 months 12 hours ago) and read 1596 times:
The wing on the B744 were redesigned totally by Boeing to be made of different materials and have different aerodynamic performance over the 747 classics. It was not simply a case of adding wingtips to the old 747 wing. In doing this, Boeing delibarately altered the angle of the chord line at the ends of the wings. This was designed to reduce wingtip vortecies and make the wing more efficient. It has an added effect of reducing the likeliness of 'dutch roll'.
The wings may flex and droop due to fuel, but the downward angle at the tips is a design feature.
I don't have any more info, but i'm sure if you try the Tech ops page someone will help out. Most likely even correct the above! (and feel free to, i only rememebr reading the above somewhere and am no expert!)
VS744 From United Kingdom, joined Aug 2001, 677 posts, RR: 1 Reply 8, posted (12 years 2 months 12 hours ago) and read 1585 times:
I also noticed this, when on the ground, I could quite clearly see the wingtip from the middle isle out of the window, but during flight, the wing had moved at least 10-15 feet upwards and I could not see the tip any longer.
I came to the conclusion that it was to do with the weight of the aircraft acting as a pulling force at the centre, and dont think it had much to do with fuel load as on landing, the wing returned to the exact same position (with no fuel).