Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: MiloMorai on February 01, 2006, 04:11:16 AM
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You all remember Crumpp's fanatical claim, in the F8F thread, about the main spar of the 190.
The FW-190's is one solid piece running throughout most of the wing. It is not bolted together or fitted from the fuselage. The wings run under the fuselage and the main spar is one continous piece.
Well I have come across some info that has the main spar being composed of seven, yes 7, seperate pieces.
There was the centre piece, then the piece to join the kinks and then from the outer kink 2 more pieces.
So much for Crumpp's claim of one continous piece. :eek:
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Can you show us the info?
-C+
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I have seen the main spar on an fw190 and it is one piece for roughly 75% of the wing's overall length. I didn't measure it but it looked to me to be an I-beam of roughly 5"x5"x 1/2" T6000 series aluminum. the piece extends out to the area roughly corresponding to where the inner aileron hinge is attached to the wing.
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Originally posted by Charge
Can you show us the info?
-C+
As soon as I get it scanned it will be posted.
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Milo has it right I belive.
Wasn't that already on the F8F thread, or could one not see it properly?
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This is gonna be good.
Waiting with baited breath...
Please post your PROOF.
:rofl
All the best,
Crumpp
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You got reading difficulties Crumpp? I said I will post when I get it scanned. :huh
Be prepared to wiggle and squirm while eating crow. :D
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Crumpp, are you sticking to this, that the main spar is a unique single piece, not bolted etc? I recall the longest single spar (bolted at wingtips I belive) was the a6m, but, alas, me and my memory ;)
I am pretty sure the 190 is joined, just less than many others.
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I am pretty sure the 190 is joined, just less than many others.
I know exactly where this is coming from Angus.
Milo has a copy of the Ersatzteilliste and he thinks he knows something he does not.
All the best,
Crumpp
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Originally posted by Crumpp
I know exactly where this is coming from Angus.
Milo has a copy of the Ersatzteilliste and he thinks he knows something he does not.
So post the relevent page so I don't have to go get a scan done.
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I will let you dig your own hole Milo.
While I am glad to help anyone out, you obviously opened this thread with the intention of attacking my integrety.
Fix your scanner and post your evidence, please!
All the best,
Crumpp
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I don't have to attack your integrity, you do a good job of that by yourself.
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Post your evidence Milo. You childishly ran your mouth, now back it up.
All the best,
Crumpp
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Ah poor little Crumpp. :(
Later tonight you will see it but could be after midnight. :)
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Crumpp, you are in a restoration crew of a 190, right?
I don't know how far you go stripping the aircraft, but surely you either have some blueprints, or you have seen it with the naked eye, right?
On second thought, seeing it means you have it all in little pieces. There were some maintenance issues mentioned if there was a whole spar.
And there I stop and wonder. Now, a whole spar, as far as goes, from tip to tip, would be stronger than a joined one, but to fix and such, vastly worse. Look at the 109. Easy to fix. Take wings off while the fuselage stands on the wheels. Change engine (both on 109 and 190) in insane speed. So, - a totally whole spar seems a bit "un-german" to me, that's all.
Guess we'll have to wait a bit. Milo will bring some light in.
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Angus, consider however that the 190 wing came off as easily as the 109's did, only it came off in 1 piece (the entire wing came off, I am guessing the fuselage was put on a truss or something), and a replacement could be bolted on quickly. The damaged one would be scrapped, canibalized, or sent back to the factory, going by other accounts I've heard during the war.
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Pulled out on one side?
It goes "through" the underside of the fuselage, so it just makes me wonder.
The 109 solution is blimming marvelous though...
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(http://img.villagephotos.com/p/2005-12/1114844/fw190spar2-1.jpg)
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Well, that solves that then!
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Where are the bolt holes Milo?
How do they put that Girder together?
Show two preceding pages if your going to be honest.
All the best,
Crumpp
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Originally posted by Crumpp
Where are the bolt holes Milo?
How do they put that Girder together?
Show two preceding pages if your going to be honest.
There are other means of assembly besides nuts and bolts.
I don't care what the 2 preceding pages have on them. You post them because I don't have them.
The spar was assembled from 7 individual pieces.
So much for Crumpp's claim of one continous piece.
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source please, which model 190 is that from? that looks nothing like the spar I saw for the A8.
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No, it is the FW-190 spar, Storch. Same one your saw, You just saw it as it comes from Focke Wulf.
Milo should probably learn something about Girder construction. Most Girders are assembled from pieces and fused together.
Where are those bolt holes again?
Milo has found the parts which are assembled at the factory once they are together you are not getting them apart without a cutting torch or saw.
My supposed deceit:
The FW-190's is one solid piece running throughout most of the wing. It is not bolted together or fitted from the fuselage. The wings run under the fuselage and the main spar is one continous piece.
Stands as a true statement.
All the best,
Crumpp
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Well that settles it. I'm convinced.
It is obvious that the wing spar was engineered per specs submitted by Hall and Gillies so that when Grumman copied the FW the spar would be ready-made for implementing folding wings. ;)
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:lol
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So, it isn't a solid spar at all. Doesn't matter how it's PUT TOGETHER, it's put together from several pieces to form a continous piece.
Point is, it has joints. punktum.
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Angus: Re wing removal: The wing is 1 piece, and the fuselage, like a 109, has its own "belly", so that it's got its own skin and structure. However, the 190 has a trench cut into it where the spar stretches through the fuselage, and it literally drops out the bottom when unbolted, and another can be bolted into place. I did a quick google search but couldn't find an image. Those folks that are building the new Fw190s (the "190s-that-arent-really-190s") had a good image with the wing beside the fuselage, but they must have taken the image down.
Re: wing spar
The argument was that the spar was solid, and could not be repaired or replaced in the field. The fact that (at the steel mill) this thing was formed from separate smaller pieces doesn't mean much. You still can't replace or repair it.
It's like a ship's hull. *THAT* is made from lots of smaller pieces, but it's 1 big piece where you can't just swap out parts if they get broken.
EDIT: Here's an example of just the wings (not sitting next to the fuselage like I wanted to show, however).
(http://fw190.hobbyvista.com/norwaywings.jpg)
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That's cool. Nice Krusty. Do you have a seperate pic of the fuselage?
Doesn't exactly run through the fuselage though (like the a6m, - I think), and with 1 wing damaged, you'll have to take the pair off.
Still, the 109 solution is quite good.
But Crumpp's point was definately a solid spar all the way, not joined at all. I understand that as "not joined at all" , and it boggled me, for it would be worse from the viewpoint of manufacture, although buing strength instead.
Anyway, the final line is that the spar was indeed combined from several pieces. IMHO it doesn't make it any worse, (rather better), much more logical really. And whether it was bolted, riveted, welded, pressed or whatever doesn't really matter. Well, with still 7 pieces, I'd use bolts probably.
Maintenace.....
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What difference does any of this make besides scoring points in petty personal conflicts?
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Originally posted by Crumpp
Milo has found the parts which are assembled at the factory once they are together you are not getting them apart without a cutting torch or saw.
Stands as a true statement.
Was only continuous after assembly, just like the Zeke.
For the Zeke "the entire wing-together with integral fore fuselage section-must be replaced" if damaged.
Just another of your not being able to express yourself correctly Crumpp.
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Was only continuous after assembly, just like the Zeke.
No the Zeke was bolted, the FW190's permanently attached together. You cannot disassemble it Milo. It is a constructed girder.
Why do you think there is part number for the whole wing assembly in the Ersatzteilliste, Milo. Two pages up from the diagram you posted it shows the assembled main spar.
The argument was that the spar was solid, and could not be repaired or replaced in the field. The fact that (at the steel mill) this thing was formed from separate smaller pieces doesn't mean much. You still can't replace or repair it.
Correct. You cannot repair it once assembled. The whole wing is replaced.
The fuselage is lifted and the wing removed.
Angus you are on the right track but it was not for ease of repair. It was for ease of assembly. The wing sections are constructed in jigs by section. When complete, the spar sections are permanently attached to form the wing. Two wings are then joined when the center section is permanently attached and the final skins applied. The main spar is one continous piece just as it states in Focke Wulfs specifications and the Flugzeug-Handbuch.
All the best,
Crumpp
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the spar I saw had no visible joints and I looked at it for some time. it appeared to be milled from a single billet. I'm amazed to see that it was joined. perhaps milo would explain how it was joined seemlessly?
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So it just like Dewoitine 1922 design.
Where is the inovation ?
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Hehe, all interesting.
"No the Zeke was bolted, the FW190's permanently attached together. You cannot disassemble it Milo. It is a constructed girder."
Firstly, on first expession, I'd think the Zeke approach would be pretty good.
But the 190 Wing is all removable though, just hooks off. cute.....
Anyway, it was an assembled spar. How? doesn't matter. Assembled.
In 1940's you could have made it a whole one, just play with paper and scissors and you know what I mean. But they took the cleverer method and assembled it from units, very much easier etc.
"Assembled whole spar", - now how's that.
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How? doesn't matter. Assembled.
Whatever you want to think.
Certainly impressed Grumman.
And the RAE.
All the best,
Crumpp
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What I want to "think"????????????
Are you missing a screw? You claimed it was a single unassembled spar and it wasn't. No matter what you "think".
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The FW-190's is one solid piece running throughout most of the wing. It is not bolted together or fitted from the fuselage. The wings run under the fuselage and the main spar is one continous piece.
Everything I said is true Angus.
Come down and check it out yourself. Storch did!
The Museum is public and anyone can visit.
Wouldn't be the first time Milo posted some silly drawing and derived at a completely wrong conclusion. The more crap he post's the better.
All the best,
Crumpp
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"Anyway, it was an assembled spar. How? doesn't matter. Assembled."
Heh heh, I wonder who could make a 10 meter main spar out of a solid piece of metal. Billet aluminun main spar. :lol
So much ado about nothing... :rolleyes:
-C+
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You can make it solid. Play a bit with scissors and paper and you'll know what I mean. Cut & bend. But it's complicated.
What bothers me here is that while actually many of us thought it must have been made out of smaller parts (gaining in the manufacture, loosing a little in strength and weight), Crumpp painted another picture. NO IT IS NOT FITTED TOGETHER.
Now, this boring haggle is not about it being better or worse (I think fitted together is a much more practical solution), but the blimming bluff about it.
Solid means solid. Assembled means assembled. Crumpp either threw a bluff, or thought it was solid, - either way, he cannot face it.
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the point being that I work with many metals. we cut, assemble, join, weld and bolt together stuff. there is no way to do it seamlessly. the spar I saw was extruded and milled there were no joints. repairing it must have been very difficult requiring the entire wing to be dis-assembled never the less the main spar I saw is one solid, massive piece of aluminum and a functional work of craftsmanship and art.
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Originally posted by Angus
You claimed it was a single unassembled spar and it wasn't. No matter what you "think".
Actually, he said it was one continuous piece, which it is regardless if it started out as more than one piece, he never said it was unassembled.
Can we move on to something constructive?
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Originally posted by storch
the point being that I work with many metals. we cut, assemble, join, weld and bolt together stuff. there is no way to do it seamlessly. the spar I saw was extruded and milled there were no joints. repairing it must have been very difficult requiring the entire wing to be dis-assembled never the less the main spar I saw is one solid, massive piece of aluminum and a functional work of craftsmanship and art.
Storch, if you work with metals you know how to read drawings. Drawings show broken lines and solid lines and you must know what they mean.
He said more than that Grits if you read the original thread.
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He said it was a solid piece. That is solid.
In complete language, solid.
A very important term in engineering. Well, I mostly know construction stuff, but solid and assembled/joined are completely different issues.
Typically, the joined will just be a wee heavier (overlapping), but structurally it doesn't mean anything, can be just as strong.
So, again, that's how I understood Crumpp, - the "one continuous piece".
After hagging with Milo, it seemed pretty "solid" to me.
And my first language isn't even English.......
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Originally posted by MiloMorai
He said more than that Grits if you read the original thread.
So what if he did? How does this further our knowlege of WWII aircraft? What does it prove other than you and Crumpp have a personal feud?
Originally posted by Angus
So, again, that's how I understood Crumpp, - the "one continuous piece".
When I read that I took it to mean "not able to dis-assemble" which is what Crumpp meant. The fact that you misunderstood what Crumpp said, and I admit he could have been more precise in his wording, has nothing to do with what Crumpp meant to say. You, and Milo, took the worst possible meaning of his less than precise wording so you can attempt to discredit him on the next meaningless pissing match you guys (both sides, not just you and Milo) get into.
Less pointless personal feuds, more constructive discussion. This thread is nothing more than a way to score personal feud points and is of no use whatsoever.
Lets move on please.
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AHA!
Territorial pissing!
Anyway, I guess I didn't misunderstand Crumpp after all, - he flushed the promotion of the matter rather than me (and others getting it wrong (?). Well, that happens. But as he was quite snappy about it, I really really thought he meant what he said. Well, ok. Move on...to something constructive perhaps?
So the 190 has a "whole wing" and therefore could be categorized with the few (?) WW2 built aircraft that took this path right?
The A6M and the Bearcat are the only ones that come to mind, but there are surely many that can shed a light on that. Were the Japanese the first to do this successfully? How is the A6M spar? What is the benefit? What is the cost?
( I imagine that the benefit is strenght and the cost is maintenance, but that of course, could be wrong)
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the good side is Kurt Tank used 3D equations in his computation
Mandatory ghey smillie :rolleyes:
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ooooohhhhh ;)
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the good side is Kurt Tank used 3D equations in his computation
Did you understand that conversation?
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milo, the spar I saw had no (zero, none, nada, goose eggs) splices or joints of any type. it was in fact one continous extrusion.
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Storch,
I believe what you are seeing as one continuous extrusion is more or less the outbd panel, which is, when assembled, a part of one continuous spar, regardless of whether it is riveted, huck bolted, bolted, or spot welded together.
The otbd panels and the center section are put together into a continuous piece that forms the wing spar. That type of construction, when joined to a wing makes it near impossible to work in the field because repair requires major disassembly, and a fixture to ensure it maintains the proper shape when reassembled.
All in all, I think this argument is stupid, as very few aircraft have a solid one piece spar that was milled out of solid billet. Many aircraft have solid spars that are put together out of many components, and whether they are assembled using mechanical or pneumatic fasteners means little. The end product is a solid spar.
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"All in all, I think this argument is stupid"
You obviousy haven't seen the diagrams of refracted light in armored glass equations yet. Heady stuff, bring a protractor.
:D
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What is this, Aero Farm? "Some spars are more solid than others"
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"Some spars are more solid than others"
Actually there are differences.
Many planes don't have:
The FW-190's is one solid piece running throughout most of the wing. It is not bolted together or fitted from the fuselage. The wings run under the fuselage and the main spar is one continous piece.
It was considered innovative at the time.
Take the P51 for example.
(http://img130.potato.com/loc9/th_60533_P51spar.jpg) (http://img130.potato.com/img.php?loc=loc9&image=60533_P51spar.jpg)
It was not continous and was bolted together. Bolts do loosen under repeated flexing.
I don't think the P47, P38, or the Spitfire had continous one piece main spars either.
All the best,
Crumpp
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Originally posted by Crumpp
It was not continous and was bolted together. Bolts do loosen under repeated flexing.
That is such an incorrect statement it is not funny.
Crump, bolts under TENSIL strength do not loosen because a spar flexes. Especially nylocks! Bolts loosen under rotation, which is why we use castlated nuts and drilled bolts in said applications.
Any failures you may try to site, will be because of improperly torqued bolts, or simple metal fatigue in the surrounding structure.
Every wreck I have ever surveyed (done a lot of 51 wreck surveying) NEVER did any of the wing attach angle bolts fail. They most often survived all the crashed (even melted into the structure from the fires) wrecks, and to top it off, unless heat stressed, almost all exhibited the same tourques they were set with.
I have worked on the airframe you mention repeatedly, at, before, and to a point after Van Meterren left and robbed (MT) blind. I am well aware of White 1's history, and it's previous rebuild. The argument that the 190's spar is one piece is sound. It was because of assembly and fasteners. Like most airplanes are.
To the rest of you arguing a multi piece 190 spar. Site me ONE example of a mass produced a/c in WW2 that had a spar that was one piece formed single billet, tip to tip. They (your detractors Crummp) will have a hard time finding that.
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Crumpp didn't get the joke. :(
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Any failures you may try to site, will be because of improperly torqued bolts, or simple metal fatigue in the surrounding structure.
Sounds reasonable. Bolts are a common structurally sound method of joining spars and are used on many aircrafts designs.
All the strength considerations with respect to riveted connections also apply to bolted connections. A bolt is, indeed, no more than an inferior rivet that is easy to apply, and can be removed easily if required. While welds and rivets require skilled work, bolts can be applied by anyone, and this is often an important consideration. Special high-strength bolts can be used in a new way, and this is discussed below.
http://www.du.edu/~jcalvert/tech/rivets.htm#Conn
Engineering wise there is no difference between a bolt or rivet for structural strength. However when welding or brazing joint strength is as strong or stronger than the base metal. If it's done right. However both are subject to their own unique difficulties. Improperly done they can weaken the structure instead of adding strength.
http://www.machinedesign.com/ASP/strArticleID/57678/strSite/MDSite/viewSelectedArticle.asp
The more I find out about these aircraft the more I realize just how much their designers knew exactly what they were doing.
All the best,
Crumpp
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Crumpp didn't get the joke.
Sorry...
:o
All the best,
Crumpp
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Only think I might add is ze Mustang was not near as stable agun platform as ze vun ninety. Yeager said so. How much Stang wing bolts had to do with this I don't know.
Yes I know Stang guns were midwing, & 190's were mostly not.
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I think overlap welds would be much stronger than bolts. Much less flex as well.
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Originally posted by Crumpp
Engineering wise there is no difference between a bolt or rivet for structural strength. However when welding or brazing joint strength is as strong or stronger than the base metal. If it's done right. However both are subject to their own unique difficulties. Improperly done they can weaken the structure instead of adding strength.
All the best,
Crumpp
Crump,
Just an FYI...
The reason engineers decided on rivets as opposed to bolts is a simple fact of weight.
The reason we do not weld aluminum spars together is metallurgy of the base metal and flex. Many of the metals we build with do not accept welds readily. Aluminum welds have a tendency towards cracks when flexed, even when properly welded.
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Originally posted by Bodhi
Crump,
Just an FYI...
The reason engineers decided on rivets as opposed to bolts is a simple fact of weight.
The reason we do not weld aluminum spars together is metallurgy of the base metal and flex. Many of the metals we build with do not accept welds readily. Aluminum welds have a tendency towards cracks when flexed, even when properly welded.
very true. aluminum welds crack from even minimal flexing. like the amount of flexing from wind loads and expansion and contraction from daily temperature variations. I'll be putting my third child through college from the earnings I make by having a truck at home with a portable mig welder and 150 feet of lead to the spool gun and welding balcony rails in the afternoons/early evenings/weekends. that money goes straight to his savings account. the best way to join aluminum is with aluminum rivets. no electrolysis between dis-similar metals and no compromising the structural integrity of the material by heating it up during welding.
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I don't see anything wrong with brazing as opposed to welding. Much lower tempature and still offers the strength of a weld. It was commonly used in WWII for aircraft construction AFAIK.
All the best,
Crumpp
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Bolts in an overlap, if they are centered will allow for flex.
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Originally posted by Crumpp
I don't see anything wrong with brazing as opposed to welding. Much lower tempature and still offers the strength of a weld. It was commonly used in WWII for aircraft construction AFAIK.
All the best,
Crumpp
name one example of brazing skins together, or spar components please.
The only bit I know of off hand is with some engine mount components.
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Originally posted by agent 009
Bolts in an overlap, if they are centered will allow for flex.
flex with bolts is not the issue here. flex in welds was what we were talking about.
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name one example of brazing skins together, or spar components please.
I can't think of any on US aircraft with the exception of tanks. Most tanks were constructed of aluminum and brazed.
The aluminum used on US aircraft was considered inferior to that used on German Aircraft.
(http://img21.potato.com/loc24/th_bd18f_page1.jpg) (http://img21.potato.com/img.php?loc=loc24&image=bd18f_page1.jpg)(http://img128.potato.com/loc24/th_0adfb_page2.jpg) (http://img128.potato.com/img.php?loc=loc24&image=0adfb_page2.jpg)(http://img142.potato.com/loc24/th_25bb2_page3.jpg) (http://img142.potato.com/img.php?loc=loc24&image=25bb2_page3.jpg)(http://img136.potato.com/loc24/th_96091_page4.jpg) (http://img136.potato.com/img.php?loc=loc24&image=96091_page4.jpg)
All the best,
Crumpp
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Originally posted by Bodhi
name one example of brazing skins together, or spar components please.
The only bit I know of off hand is with some engine mount components.
I was a member of the weeks air museum here in miami before hurricane andrew wiped the place out and kermit weeks moved up state to polk city florida. I had many opportunities to be up close and personal with all of the inventory including sit in the aircraft on "family days" those were sundays that were set aside for members to enjoy each other's company and watch all of the flyables fly and look, touch, smell the entire collection. he had a beautifully restored P-51D done in the markings of George Preddy's "Cripes a Mighty" (the 1987 golden wrench award winner at oshkosh) the wing tips were brazed that is oxy/acetyline and aluminum rod welded. easily the most boogered up example of welding I have ever seen. apparently it was the way it was done prior to mig welding and quite historically accurate. that's the only example that I know of.
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I should have been specific and said structural skins Storch.
As for the fuel tanks being brazed, most examples that we have were simply stamped steel (USAAF) that were Crimped and spotwelded together.
USN tanks, like MK12's were aluminum in some cases and sometimes steel. All versions we have were spot welded. The Hellcat specific tanks (can not think of P/N off hand) were stamped steel, and spot welded.
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Flex period is the issue. Both welds & bolts are relevant as both were used in war.
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Flex period is the issue.
Probably why the FW-190 spar is provided with a riveted top and bottom cap to further strengthen the joints.
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If someone could toss up a diagram or photo of say a Mustang wing spar, with closeup of bolts, it would help to see which is stronger. 4 bolts better than 2 etc. I still say weld is better
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(http://img138.potato.com/loc3/th_d1963_P51spar.jpg) (http://img138.potato.com/img.php?loc=loc3&image=d1963_P51spar.jpg)
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Kinda hard to see. but should help somewhat.
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Be grateful someone did the work of posting it for you.
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Originally posted by Crumpp
Be grateful someone did the work of posting it for you.
:rofl he probably gripes about farmers too. :aok
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I am grateful Crump. I just can't see the bolts & how they are installed or how many per seam.
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Np, your welcome. You got photoshop? download it and enlarge.
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See Rule #4
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Read the freaking argument
There is no argument Bodhi.
The alloys were different so it's not really comparible. There are no examples of US aluminium spars being welded but there are some examples of aluminum welds on US aircraft.
That has little to no bearing on axis aircraft.
FYI FW-190 spar is provided with a riveted top and bottom cap to further strengthen it.
All the best,
Crumpp
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See Rule #4
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See Rule #2, #5
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Originally posted by MiloMorai
(http://img.villagephotos.com/p/2005-12/1114844/fw190spar2-1.jpg)
Section 5 is no bolted connection. There was the vertical connection to the fuselage (see little holes upperside), therefore they mounted a stronger spar.
The holes in the wing for the guns weakend the wing, thus the spar was strenghted with extra plates around the hole. The numbers there donīt indicate a bolted connection but probably the extra plates.
Flugwerk fw190 has not the holes for the gun in the wing afaik, so they donīt need the strenghtening.
niklas
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See Rule #4
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probably the extra plates.
Those are riveted which is equal to being bolted.
I've tried to make it crystal clear that the spar could not be disassembled and was permanently afixed together without spoiling the details for the Museum.
We are going to be putting out some published material on the FW-190 hopefully soon and I am not really interested in making it "old news" before it hits the market.
All the best,
Crumpp
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So what is the best way to assemble a spar?
Rivets? Bolts? Welds?
I'd put my bucks on welds being the strongest, and bolts being the easiens and most friendly for maintenance. Bolts might still be the unsafest.
Just a thought.
Oh, and if you could make the spar all solid, (1 piece) it would be the strongest of the lot for what it weights..,.
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You better donīt weld such a main spar. The deformation due to thermical stress would be too high. Even minor angle deviations from welding at the inner part would influence a lot the position of the wingtip due to the length. Welding also reduces the stress a lot, really a lot.
niklas
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The welds reduce the flexibility right?
But the attachments can join and be welded on rather a large area.
Well, overlapping and bolted is quite strong also.
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Actually brazing is not nearly as destructive and if done properly and offers the similar strength to wielding.
The strength of brazed joints depends on many factors, like dimensions and clearance, brazing-material and absence of defects in the joint itself. Usually it can exceed application requirements, sometimes even base metal strength.
http://www.welding-advisers.com/Brazing.html
It very much depends on the alloy used to how well it either method works.
http://www.welding-advisers.com/Welding_aluminum.html
Welding aluminum is actually more common in the aerospace industry than one would believe from reading this thread.
Designers of aerospace structures can use the higher elastic modulus, lower density, and, in some cases, higher strength and fracture toughness of aluminum-lithium alloys to reduce structural weight.
The advantages of aluminum-lithium alloys over conventional aluminum alloys include relatively low densities, high elastic modulus, excellent fatigue and cryogenic strength and toughness properties, and superior fatigue crack growth resistance.
The use of aluminum-lithium alloys does not require changes in manufacturing equipment, design methods, or fabrication techniques. In particular, aluminum-lithium alloys have been found to be readily weldable.
http://www.welding-advisers.com/PRACTICAL_WELDING_LETTER-PracticalWeldingLetterNo21.html
Welding-aluminum is concerned with aluminum alloys weldability. This is a qualitative assessment of the material suitability to be welded by a certain process in a properly designed structure under given conditions, to present a specified quality level (that is without unacceptable defects), and to perform in service according to given requirements.
Therefore...
...materials like aluminum alloys may show different weldability in different conditions for different processes but may still be satisfactorily welded with particular precautions, generally spelled out in detailed procedures.
Welding-aluminum is easy for certain aluminum alloys, in that it can be done without special precautions by most welding processes under most conditions to provide acceptable and consistent welds. It should be remembered however, that aluminum produces easily, just by sitting in air, an impervious layer of aluminum oxide which protects the surface from corrosive attacks, but also interferes with welding. Special cleaning procedures are required to remove the oxide before welding or brazing.
Welding-aluminum alloys raw materials is performed on Castings, Forgings or Wrought product forms. The properties which make these materials useful for various applications are mostly low density (specific weight), which is about one third that of steel, ease of fabrication, good thermal and electrical conductivity, pleasant appearance, corrosion resistance and also useful relative strength.
Welding-aluminum can be performed on alloys of different properties. The outstanding characteristic of aluminum is its lightness, which is put to profit in transportation, cars, boats, trains, aviation, and moving machine elements. Some of the alloys can be hardened by special procedures of heat treatment, while others can only be strengthened by cold work and deformation.
http://www.welding-advisers.com/Welding-aluminum.html
Among the disadvantages, the fact that the joint must conform to certain requirements of overlap form, length and clearance, so that butt joints are not recommended, the fact that brazing-alloys are generally more expensive, the use of flux which introduces one more variable, and the need to eliminate its residuals in order to prevent corrosion, the fact (if objectionable) that color of brazing-alloy may be different from that of base metal, some limitations which may arise as to which finishing processes are permitted, and possibly issues of resistance to corrosion, which might be impaired if the brazing joint is less resistant than base material.
The lower cost 6061 Al attains typical values of 310MPa, which is also superior to, for example, A356 (or 601 type) Al casting alloy whether that alloy is semi-solid cast, squeeze cast or gravity cast. Further fabrication by welding is also available with 6061 aluminium, opening the opportunities for many other applications.
All the best,
Crumpp
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Originally posted by Bodhi
flex with bolts is not the issue here. flex in welds was what we were talking about.
For aluminum (and quite a few steels) crack avoidance is best gained by normalizing the finished piece, essentially an annealing process. Welding of any kind puts tremendous stresses in the material, due to the temperature difference between the material at the weld site and the rest of the piece.
I don't know what temperature you would use to normalize a particular aluminum alloy, but it would be between 500 and 900 F.
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We do not weld anything that is structural in a spar. Thats why fasteners are used. Hell, about the only thing we ever weld are the original weld joints in specific original fairings joints and such. As for annealing a weld, like an engine mount (Steel), we gas weld the piece allowing it to self anneal in the process.
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We do not weld anything that is structural in a spar. Thats why fasteners are used. Hell, about the only thing we ever weld are the original weld joints in specific original fairings joints and such. As for annealing a weld, like an engine mount (Steel), we gas weld the piece allowing it to self anneal in the process.
Are you working on any FW-190's?
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Have in the past, doing American stuff now. A little bit ago, I did a feasibility study on a couple of projects (190's) that are not in the country for a buyer. Both airframes are fairly complete, newly found, with good history. You'll probably hear of them in a few months or so.
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Well then you should know how the mainspar is constructed.
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It is multiple pieces connected together to form a solid one piece spar that is not designed to come apart. Like I said from the beginning.