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Sleekjet From United States of America, joined Jul 2001, 2045 posts, RR: 24
Posted (8 years 11 months 3 weeks 1 day 8 hours ago) and read 2141 times:

Freshly appearing in the latest photos is this:

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Photo © Roel Kroes

Can someone answer the question he has posed in the caption?

II Cor. 4:17-18

10 replies: All unread, jump to last

Airplay From , joined Dec 1969, posts, RR:
Reply 1, posted (8 years 11 months 3 weeks 1 day 7 hours ago) and read 2111 times:

Its hard to tell if those particular wrinkles are permanent or not, but many airframes (especially old battered ones like the subject 747) often have permanent ripples and wrinkles in the skins.

CdfMxTech From United States of America, joined Jul 2000, 1338 posts, RR: 29
Reply 2, posted (8 years 11 months 3 weeks 1 day 3 hours ago) and read 1937 times:

The Wrinkles and Buckles have an unofficial name...I think it is "Oil Canning". They are permanent (Section 46 is especially susceptable to this condition), though more noticeable at times than others. They are normal as defined by Aircraft Structural Repait manuals as long as they do not contain cracks and go through fasteners. Couple of other things as well, but can't recall.

[Edited 2004-06-09 07:51:07]

Toni_ From Cape Verde, joined Apr 2002, 70 posts, RR: 0
Reply 3, posted (8 years 11 months 3 weeks 22 hours ago) and read 1822 times:

"Will these be permanent or just because of the pressure of the landing?"

These wrinkles are normal and not permanent. What you see is the rear end of the fuselage bending a bit downwards caused by the weight of the tail during that heavy landing. It shows how flexible these planes are. Same happens when a plane is on a tailjack during maintenance. These same wrinkles will appear on top of the plane.

Greetz Toni

Life... As it is..

BritPilot777 From United Kingdom, joined Apr 2004, 1075 posts, RR: 3
Reply 4, posted (8 years 11 months 3 weeks 22 hours ago) and read 1816 times:

Just looks like heat haze to me from the engines

Forever Flight

FredT From United Kingdom, joined Feb 2002, 2184 posts, RR: 26
Reply 5, posted (8 years 11 months 3 weeks 22 hours ago) and read 1808 times:

Those diagonal wrinkles is the way the skin of a stressed skin aircraft takes up the stress. They will always be present when there is a load on the structure, to a larger or smaller degree. Structural engineers spend a lot of time analysing them. As time and cycles build up, they often become more apparent.

Cheers,
Fred

I thought I was doing good trying to avoid those airport hotels... and look at me now.

A/c train From United Kingdom, joined Jun 2001, 501 posts, RR: 4
Reply 6, posted (8 years 11 months 3 weeks 17 hours ago) and read 1714 times:

Tonis explanation sounds good, were I work I always noted when I was on the fwd jack that the skin would wrinkle around the jacking point and then go away on lowering, therefore they are not permanent, there are .040" skin pockets in that area so it doesnt surprise me.
regards a/c

Diezel From Netherlands, joined Oct 2002, 646 posts, RR: 12
Reply 7, posted (8 years 11 months 3 weeks 10 hours ago) and read 1588 times:

I took the picture, thanks for reacting !

I also got an email from somebody who says that the wrinkles are permanent but will disappear when the aircraft is pressurized.

Roel.

Never be afraid of what you like. (Miles Davis)

Aloges From Germany, joined Jan 2006, 8358 posts, RR: 47
Reply 8, posted (8 years 11 months 3 weeks 1 hour ago) and read 1513 times:

Here's another fine example of wrinkles, also on a KLM 747:

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Photo © Stephan Curkowskyj

Walk together, talk together all ye peoples of the earth. Then, and only then, shall ye have peace.

MD-90 From United States of America, joined Jan 2000, 8418 posts, RR: 13
Reply 9, posted (8 years 11 months 3 weeks ago) and read 1501 times:

Look at the wing of every strut-braced Cessna ever built and they will all exhibit oil canning. It tends to be less visible on airliners because they have thicker gauge skins.

Liamksa From Australia, joined Oct 2001, 308 posts, RR: 0
Reply 10, posted (8 years 11 months 2 weeks 6 days 22 hours ago) and read 1481 times:

It's fascinating to watch the ripples in a low-wing aircraft when pulling a few G's. Kind of startling / amazing how much the wings flex and how much slack you can get on the top surface wing-skin! Wow!

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