main spar of the Fw190

[straffo]

the good side is Kurt Tank used 3D equations in his computation

Mandatory ghey smillie

[Angus]

ooooohhhhh

[Crumpp]

the good side is Kurt Tank used 3D equations in his computation

Did you understand that conversation?

[storch]

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.

[Bodhi]

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.

[Squire]

"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.

[justin_g]

What is this, Aero Farm? "Some spars are more solid than others"

[Crumpp]

"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.
 

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

[Bodhi]

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.

[justin_g]

Crumpp didn't get the joke.

[Crumpp]

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

[Crumpp]

Crumpp didn't get the joke.

Sorry...



All the best,

Crumpp

[agent 009]

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.

[agent 009]

I think overlap welds would be much stronger than bolts. Much less flex as well.

[Bodhi]

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.