"Short Wave Sportfishing" wrote in message
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On Sun, 13 Jan 2008 00:39:08 -0500, "Eisboch" wrote:


"Canuck57" wrote in message
news:wHdij.60275$EA5.19428@pd7urf2no...

wrote in message
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First, rivets are used on aircraft for the following reasons, not all of
value on a boat:

- low weight per attached foot of seam than welding
- cheap and manufacturing ease of use
- thermal expansion and flex
- can be drilled out for access/repair/inspection
- welding is more expensive per attached foot than rivets


Are other opinions welcome, yes.

I think aluminum welds are fine as long as they are reinforced or the
sheets
are relatively thick. Thin sheet (seam) welding of aluminum is prone to
cracking when subjected to even a little flex as compared to other metals.
Maybe someone with knowledge of metallurgy can explain the crystalline
structure, etc. My opinion is based on experience in industry.

BTW, I think flex is much more important in airplane wings than you give
it
credit for. Next time you fly, note the location of a wing tip as the
airplane begins it's take-off run and watch it as you become airborne.
While flying in turbulence, watch the tip of the wing again. There's
quite
a bit of wobbling around going on out there. Welded aluminum panels
wouldn't last long, nor would the wings if they were designed to be stiff
rather than being allowed to flex.

Thnk B-52. :)

I read somewhere that the wing of the B-52 flex up to six feet from
wing root to tip.

Can't verify that.

I would say six feet at least. Even the wings on commercial airplane like
the 767s and 747s flex close to that at takeoff and in heavy turbulence.

Eisboch