I don't see a reason that an alternate attachment of the tubes can't be used.
I
would advise caution to ensure that the connection design does handle the
loads
presented.

-------------------------------------------------------

Dear Doug,

No problem. Other methods can (and have) been used. (Numerous examples of
gusset & pin fuselages using square tube and even angle-stock, both extruded &
self-bent).

A point often overlooked is that Mr's Warren, Pratt & Howe didn't do the twist
:-) They just sat there, waiting for the next train to come along. The tricky
bit with a fuselage is what happens when you have to deal with a complex load
(ie, tension, compression & torque). The usual solution was a mare's nest of
wire diagonals and the need to 'tune' the fuselage every time the weather
changed. Attempting to emulate this method using using pinned joints
consisting of struts & gussets throws you back into the task of transferring
the load through the cluster, which is now a morningstar collection of gussets,
at least as difficult to weld (or otherwise fabricate) as a conventional tubing
cluster.

I think the real point here is that if you're going to use round steel tubing
you'll find there are more reasons to stick with accepted welding practices
than to depart from them. But it's really up to you. It's your plane; you can
build it any way you want.

Best example of gussetted steel structures is probably towers of various types
that are subjected to wind loads (ie, complex loading). Interesting to note
that when minimum weight is a consideration they abandon gusseted angles in
favor of cluster-welded tube. (Rohn, etc.)

-R.S.Hoover