Re: ATM Source for Fiberglass, Carbon tubes

[Spencer Roedder <roedder@roedder.com>]

At 01:58 PM 97/06/09 -0400, Kurt Hillig wrote:
...
>4" diameter x 1/16" wall aluminum tubing has the same weight per foot of
>length as 1/2" aluminum rod, but it's many orders of magnitude stiffer. 
>Since stiffness varies with the cube of the moment, and the moment goes as
>the square of the dimension, a factor of 10 increase in modulus allows
>only a 30% reduction in size.

A little miscalculation there: the 4" tube is equivalent in cross sectional
area to 1" rod - which is a _heck_ of a lot stiffer than 1/2" rod, though I
agree, not as stiff as the 4" tube.

--Spencer Roedder   roedder@roedder.com