"Jim Adney" wrote in message
...
On Fri, 17 Dec 2004 17:50:14 +1300 Lawrence D'Oliveiro
wrote:

In article ,
Jim Adney wrote:

A hollow circular arrangement, even helical, would only be an unstable
equilibrium. Any perturbation would cause it to collapse.

Tell that to your water pipes, your chimney, tubular car chassis
members, and all kinds of other hollow building components where
strength and lightness are both required.

Those are all solid parts, except possibly for the chimney. I
completely agree that solid tubular construction is one of the best
ways to go.



Tubular chassis aren't solid, they're hollow tubes as the name implies, ask
anybody who's worked on race cars. For the weight, a hollow tube is stronger
than a solid rod, note that this is weight, not diameter, yes a solid rod of
the same diameter is stronger than a hollow one, but many times heavier.