John D. wrote:
On Mon, 1 Mar 2010 17:52:39 -0500, "Ed Huntress"
wrote:

"Bill McKee" wrote in message
m...
"RAM³" wrote in message
. 10...
"Bill McKee" wrote in
m:

Why not aluminum? I have an aluminum boat trailer. Works very well.
3400# boat. The Covette has an aluminum frame as well as the Cadillac
bodied Vette. Look at a Corvette and see what they use. Airplanes
have aluminum frames. And as long as you design well, the flex should
not be a problem.

Boat trailers are rarely twisted the way that off-road vehicles routinely
are.

The same thing applies to Corvettes.

After all, when was the last time that you went rock-crawling with your
'Vette? Grin

How about mud-bogging or bouncing around on deeply-rutted roads?

Jeeps are expected to do all of these and more without any ill effects.
(Getting dirty/muddy is, for a Jeep, a good thing!)
Hell, I raced a vette, steel chassis, and it got to rock clrawing a couple
times. :) And boat trailers are regularly towed over uneven ground.
With three points taking out the loads -- hitch and suspension supports,
which generally are paired but close -- there is no significant torsional
load on a boat trailer. It's all simple bending. You can deal with that, but
if you towed your boat 100% of the time, I think you'd develop fatigue
problems in aluminum.

The aluminum Corvette chassis are semi-space-frame with some shear panels.
The subframes resolve their loads in three dimensions. There isn't much
flexing there.

The same applies to aircraft, which often are near-monocoque. If they flex,
you die.

Error.. ever see the wings on a B-52? When they taxi out for take-off
both outrigger wheels are on the ground; when they come back one
outrigger will be ten feet in the air. But not only the wings, a B-52
on the ground has large wrinkles on each side of the fuselage, forward
of the wings; flying the fuselage is smooth.

For what it's worth, I was told that the fuselage
skin on a B-52 was unwrinkled until they started
flying them at 100ft off the ground at 500mph or
something...