lightnattic………….got anymore drivel like that??

what you see on that B52 is a perfect example of a diagonal tension stress field. This occurs when the skin panel(denoted as the areas surrounded by both horizontal and diagonal stiffeners) can no longer maintain its shape under an applied load, this can be horizontal, vertical or a combination of both. The panel will buckle to relieve the stress in the structure, and the stress is converted to a load carried along the 45 degree diagonal.

this load is being caused by the weight distribution over that part of the aircraft, in this situation. whilst i am not involved with the stressing of fuselage’s (I am a wing man) I do know that the hoop stresses in the fuselage stiffeners must account for the fuselage acting under pressure.

The skin will not shrink by a great deal at altitude (certainly not enough to tension that amount of slack) but what will happen is that there will be a little additional rigidity due to the pressurised cabin (if indeed the pressurised cabin is sealed via the fuselage skins, which i do not know), and you will get some support from dynamic pressure.

I would suggest that even with the two elements combined this is not enough to support the fuselage and unbuckle the skin (the nose needs to be propped up in order to unbuckle the panels).

Of course they could have used a slightly thicker grade of skin panel, or added more stiffeners (this would have been the lighter solution) as it is, this must be fatigue certified to fly in that condition (we would not design our parts to operate normally in a buckled state, unless there was a specific purpose, but i won’t go into that as its a bit work-sensitive). Certainly, we can let some metallic structure buckle a certain number of times, but you probably wouldnt want to see it if you were a nervous passenger!

coanda

nice pictures guys!

hmm ok, i think most people would class anything other than bombs as somthing else………say missiles 😉

surface imperfections are one thing, whole scale airframe deformations due to heat soaking at high temperature are an entirely different thing. The heat concentrations around things such as bolt holes and joint lines will be massive, so they will be limited or moved to a point where they are no longer such a problem, thats just good engineering judgement. Stealth aircraft already go to great lengths to conceal and otherwise deal with bolt groups and joint lines, a hypersonic aircraft would be no different.

don’t think its that big a gap sferrin.

i wonder if a self generated electric field/screen would prove to be a suitable heat shield……..

still, I have been treated with contempt by volunteers, seemingly keen to keep their clique to themselves (and they are quite welcome to it).

I learnt all my aerial habits with a great bunch of forces guys, as a cadet in the ATC, and frankly, flying clubs are places that I just don’t like going to (I did a flying scholarship with one at wolverhampton intergalactic business megaport, which was enough for me).

I’d call myself an enthusiast (I get paid to design parts of airliner wings), and a photographer, but not a spotter. Interestingly, work has the same divide……….I heard one guy once say that the company shouldnt employ engineers who had admitted to actually liking aircraft, because they would be rushing to the window every 2 minutes……..ahole. such is this attitude that many people in the company i work for are closet enthusiasts (no………..nothing to do with wardrobes, fitted or otherwise) and whenever we mention somthing about aircraft it must always be qualified with a derisive comment about spotting!

MrBlueSky, Thanks very much! that info is very useful!

I’d love to get hold of a 3 view of a Rotodyne to put it into the x-plane sim!