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Hard Landings, Shear Buckling, etc.

Hard Landings, Shear Buckling, etc.

Hard Landings, Shear Buckling, etc.

(OP)
Used to be, you couldn't get this close to this plane without enlisting, or risking a bullet:



Those with a good eye for structures will notice some wrinkles. Looking a bit closer...





That's actually a LOT of wrinkles. They continue all the way up the nose to the gunner's deck.
Hard landing? Pulling G's in flight?

No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
STF

RE: Hard Landings, Shear Buckling, etc.

I have seen that on many older aircraft. I always assumed that it was normal to a certain extent, but you should know better than I.

RE: Hard Landings, Shear Buckling, etc.

this is probably abuse, but many light s/m skins have elastic buckles on the ground that get relieved in flight often with cabin pressure.

another day in paradise, or is paradise one day closer ?

RE: Hard Landings, Shear Buckling, etc.

RB1952...

You are generally correct... these are standard BUFF 'beauty-wrinkles' due to gravity on all unpressurized B-52s... and often KC-135s.

Boeing's early jet fuselages tended to have closely spaced longitudinal stiffeners and widely spaced body frames, with very thin skins [often spot-welded to thin internal doublers to minimize riveting issues]... which saved weight but promoted elastic skin-wrinkles on the ground. Some internal webs are 'so thin' that 'high-time' cracking due to flexural buckling/tensioning is a genuine maintenance nuisance [and was generally predicted by pressurization fatigue tests].

NOTE.
'Jig-jacking' the airframe [jacking into a manufacturing jig-position]... or in-flight pressurization... generally relieves [smooths-out] a high percentage of these body wrinkles.

NOTE.
On-the-other-hand, early high-wing Lockheed transports [C-130, C-141, C-5] tended toward thicker/stiffer webs and body skins... so these rarely show wrinkles due to static gravity loads... and typically have fewer internal web cracks over their service life.

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

RE: Hard Landings, Shear Buckling, etc.

hey Will … don't make me 5 years older … please !

another day in paradise, or is paradise one day closer ?

RE: Hard Landings, Shear Buckling, etc.

rb'57... dang, Freudian SLIP...

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

RE: Hard Landings, Shear Buckling, etc.

Although I could not do it now (64 years old this year) when I was 18-20 I spent two years crawling around inside those beautiful birds and thoroughly enjoyed (almost) every minute of it. I should note that I worked the H models, however, and the one in the photograph is a G model.

I still remember the way the hair stood up on the back of my neck when I was on the flight deck of a B-52H working on the avionics the day I saw my very first nuclear weapon travel down to the alert area to "cock" an aircraft for war. Thank God the war stayed "cold" because I never wanted to see those alert birds go for the real thing.

Nowadays I have at least as many wrinkles as the BUFF in the photo, and neither jig-jacking nor pressurizing me would make then go away!

RE: Hard Landings, Shear Buckling, etc.

At Kadena I crossed-paths with an older HS teacher, who 'sported' major hearing aids.

Finally one day I asked obvious question: 'what happened to cause his hearing loss?'

He kinda hesitated before he replied... I could see some pain flicker in his eyes.

He was a navigator on a B-52 mission over North Vietnam. At ~50,000-Ft, just after dropping their bomb load, a SAM detonated ~100-ft** under the jet just below the flight deck and forward bomb-bay. The sudden depressurization... blew-out almost everyone's eardrums and 'caused other injuries/pain'. Some mechanical systems went-down, but the BUFF held together and was flyable, so the crew kept it airborne to get away from territory they just bombed. They eventually landed the crippled jet at a divert base.

The entire flight crew lost their hearing [individually to greater/lesser extents] and he suffered sudden decompression injuries for weeks afterwards.

BUT... They were alive and they didn't have to eject over NVN!

He/most-of-the-other-guys never flew [missions] again... and their jet was scrapped on-site.

** SAM 'hit' was witnesses from a near-by BUFF. That crew could barely believe their jet didn't fold-up like a cheap suit... like others had.

Regards, Wil Taylor

o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

RE: Hard Landings, Shear Buckling, etc.

Those wrinkles will buff out.

RE: Hard Landings, Shear Buckling, etc.

(OP)
I am "this" far from red-flagging you, 3DDave.

So I thought it was a -52H. What am I missing? (I'm a youngster, you see...)

No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
STF

RE: Hard Landings, Shear Buckling, etc.

Comcokid is correct, but I determined it was a G model in a slightly different way. The tail profile (first OP photo) is the shortened version, which only existed on the G and H models. The A through F models had a taller tail which more closely approached an apex point. The G and H model tails always stand out to me by their profile.

Second, once it was down to a G or an H, then I looked at the engines. The OP photo aircraft has the older J-57 turbojet engines (see again first OP photo), but the H had the newer TF-33 turbofans with the oversize inlet cowls (see my photo of an H below). The TF-33 engine on the H is why the H models at takeoff power never created exhaust clouds of such starkly monstrous size and dark coloration as the J-57 engines did with water injection.



RE: Hard Landings, Shear Buckling, etc.

I got to tour Edwards AFB when I was in undergrad, and all of the B-52s we saw there had the same wrinkles. They told us it was caused by the thousands of pressurization/depressurization cycles the airframes had seen during service. You could look down the fuselage from the nose and see it wobble in, out, in out between each frame.

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