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747-400 Wing Flex

Js From Malta, joined Aug 2001, 107 posts, RR: 0
Posted (9 years 1 week 3 days 15 hours ago) and read 4879 times:

Using the winglets as a point of reference, these two pictures gives some idea as to how much a 747-400 wing flexes on takeoff! Can anyone estimate the difference in height?

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Photo © Royal S King

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Photo © Andrew Simpson

21 replies: All unread, jump to last

Philsquares From , joined Dec 1969, posts, RR:
Reply 1, posted (9 years 1 week 3 days 15 hours ago) and read 4845 times:

At MTOW the wing flex is almost 3 meters at the tip as compared to the wing tip position on the ground.

FL1TPA From United States of America, joined May 2004, 258 posts, RR: 0
Reply 2, posted (9 years 1 week 3 days 15 hours ago) and read 4809 times:

Looking at the flex from the angle in the photo below is quite amazing! The engineering that goes into these aircrafts is mind-boggling.

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Photo © Joe Pries - A.T. TEAM

WOW!

<>

"Looks like I picked the wrong week to stop sniffin' glue."

Jetfixer75 From United States of America, joined May 2004, 29 posts, RR: 0
Reply 3, posted (9 years 1 week 3 days 13 hours ago) and read 4690 times:

The 747-400 wing can deflect a total of 29 ft from top to bottom before the spars fail!!! Absolutely amazing. I have the destructive test on video when Boeing does this, sounds like a bomb going off

Smcmac32msn From United States of America, joined May 2004, 2211 posts, RR: 5
Reply 4, posted (9 years 1 week 3 days 13 hours ago) and read 4679 times:

Jetfixer75 - Is that a personal video, or can you post it for us to see?

Hey Obama, keep the change! I want my dollar back.

Md80fanatic From United States of America, joined Apr 2004, 2639 posts, RR: 10
Reply 5, posted (9 years 1 week 3 days 13 hours ago) and read 4670 times:

That last pic shows an unusual amount of flex.....due primarily to the fact that the pilot has extended his slats....which creates a very large roiling motion of the air below the wing increasing pressure greatly (extra lift). That has to be the most that wing can flex before a stress fracture appears. That pic's a keeper for sure.

LVZXV From Gabon, joined Mar 2004, 2041 posts, RR: 44
Reply 6, posted (9 years 1 week 3 days 12 hours ago) and read 4647 times:

I remember reading that passengers noted an abnormal amount of wing flex on a BA 741 flying JFK-LHR c.1999. One passenger even described a mild "flapping" notion during the cruise. When the aircraft landed, it was withdrawn from service and immediately inspected. The Jumbo had crossed the North Atlantic with a BROKEN wing spar!!! Wow!

Beat that Airbus!!! Big thumbs up

How do you say "12 months" in Estonian?

ATA L1011 From United States of America, joined Feb 2001, 1362 posts, RR: 7
Reply 7, posted (9 years 1 week 3 days 12 hours ago) and read 4629 times:

All of the long wing modern widebodies have lots of flex in cruise,takeoff and landing including these;

767
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Photo © Carlos A. Morillo Doria

777
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Photo © Aaron Mandolesi - Mile High Images

A330/A340
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Photo © Andreas Stoeckl

I have noticed lots of flex on these models.

Treat others as you expect to be treated!

B4real From United States of America, joined Aug 2003, 2595 posts, RR: 6
Reply 8, posted (9 years 1 week 3 days 11 hours ago) and read 4557 times:

Jetfixer75:

IIRC wasn't 29 feet where the 777's wings fall apart? That video was public on the Discovery channel recently. They re-run the doc on the 777 periodically, also on Discovery Wings.

B4REAL, spelled like it sounds

AirPortugal310 From United States of America, joined Apr 2004, 3104 posts, RR: 2
Reply 9, posted (9 years 1 week 3 days 11 hours ago) and read 4546 times:

Seems to me that the longer the wing, the greater the chance of flexing...rational thinking or just obvious?

I also think that the location of the engine matters, so that may be just coincidence!

Latah
Bruno

Rock Lobstah!

NoelG From , joined Dec 1969, posts, RR:
Reply 10, posted (9 years 1 week 3 days 6 hours ago) and read 4424 times:

I flew on a MH 747-400 recently from KUL-LHR and it was amazing to see from behind the wing the difference - before pushback the wings (being full of fuel) were bent down at the end, hardly giving enough room for the fuel truck that was there.

After landing, as we taxied in, we went past a BA A320 and the wingtip was higher than we were in the cabin, higher than the A320 as well!

Quite interesting to see the difference!

Rotate From Switzerland, joined Feb 2003, 1480 posts, RR: 18
Reply 11, posted (9 years 1 week 3 days 5 hours ago) and read 4368 times:

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wingflex is definetely higher/greater due on landing, than on takeoff ....

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Photo © Rotate

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Photo © Rotate

I love it when both wingtips are visbel above the a/c Big thumbs up

robin

ABC

NBGskygod From United States of America, joined May 2004, 604 posts, RR: 1
Reply 12, posted (9 years 1 week 2 days 15 hours ago) and read 3610 times:

The more weight the plane has the more the wing will flap. The C5's wing flapping is so bad it has a damping system to limit it, if that system fails the plane tends to resemble a large bird flapping through the air, and I would imagine not too much fun for those riding inside.

"I use multi-billion dollar military satellite systems to find tupperware in the woods."

WhiteHatter From , joined Dec 1969, posts, RR:
Reply 13, posted (9 years 1 week 2 days 15 hours ago) and read 3484 times:

If the wings DIDN'T flex I'd be worried! Nuts

Flexing is designed into the wings of large aircraft. If they just sat there rigid, then where would the changes in stress and vibration be going? A fully rigid wing on a 747 would be under all kinds of changing pressures and much more prone to stress fractures.

Think of dropping a plate on the floor. A bendy plastic one just bounces, a ceramic/pottery one shatters. That flex absorbs a lot of punishment and shock!

Aviopic From Netherlands, joined Mar 2004, 2681 posts, RR: 46
Reply 14, posted (9 years 1 week 2 days 15 hours ago) and read 3451 times:

I hardly see any flex in a 743 wing, can someone tell me the difference in flex movement between 744 and 743.
I have read the 744 wing can flex 29ft. but what about a 743 wing ?

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The truth lives in one’s mind, it doesn’t really exist

Toni_ From Cape Verde, joined Apr 2002, 71 posts, RR: 0
Reply 15, posted (9 years 1 week 2 days 13 hours ago) and read 3405 times:

That's because of the greater wingspan. The 744 has a wingspan of 64 meters, and a 747 classic 59 meters. And also I think the winglets make it a bit easier to detect the wing flex from a distance on a 744. It's the combination of winglets and great wingspan that make the A330 look like a huge albatross stretching its wings while gliding above the ocean.

As for the max a 743 wing can take... I think the first 747 test wing back in 1969 snapped at 10 meters... Still very impressive!

Life... As it is..

Starlionblue From Hong Kong, joined Feb 2004, 15904 posts, RR: 66
Reply 16, posted (9 years 1 week 2 days 6 hours ago) and read 3263 times:

As for flying with a broken wing spar, the 747 cheats since it has three spars as opposed to the usual two. Big grin

"There are no stupid questions, but there are a lot of inquisitive idiots." - from Citadel by John Ringo

LVZXV From Gabon, joined Mar 2004, 2041 posts, RR: 44
Reply 17, posted (9 years 1 week 1 day 14 hours ago) and read 3093 times:

10 metres = 30 feet

All 747s have the same SPAR, hence they all snap within a foot of each other.

XV

How do you say "12 months" in Estonian?

Jetfixer75 From United States of America, joined May 2004, 29 posts, RR: 0
Reply 18, posted (9 years 1 week 1 day 8 hours ago) and read 2973 times:

The video I have is from Discovery Wings. It was taken during the destructive testing of the 744. I'll have to look for it and see if I can figure out how to post it on here.

Squirrel83 From , joined Dec 1969, posts, RR:
Reply 19, posted (9 years 1 week 22 hours ago) and read 2889 times:

I love the NW JFK 747-4 Dept picture

As stated ~ WOW

Looking at the flex from the angle in the photo below is quite amazing! The engineering that goes into these aircrafts is mind-boggling.

I love 747-4 they are really quite amazing but Just think if you were to see a smurf in the isle?

Go3Team From United States of America, joined Mar 2004, 3266 posts, RR: 21
Reply 20, posted (9 years 1 week 22 hours ago) and read 2878 times:

"I'll have to look for it and see if I can figure out how to post it on here. "

Try: http://www.movie-host.net They handle uploads up to 35 megabytes. Totally anonymous, and free.

Yay Pudding!

Starlionblue From Hong Kong, joined Feb 2004, 15904 posts, RR: 66
Reply 21, posted (9 years 1 week 19 hours ago) and read 2811 times:

For the record, 10 metres = 32.8 feet.

Source: www.onlineconversion.com

"There are no stupid questions, but there are a lot of inquisitive idiots." - from Citadel by John Ringo

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