wrote

I don't think I'd want such a spar as this to be built by someone who
wasn't either thoroughly trained and apprenticed or who would be
eventually flying it. It's a most elegant piece of engineering and is
the most complex and time-consuming part of the whole airplane. One
foolish mistake in jigging or gluing could just about trash the whole
thing.


It is possible to use mass production techniques to this whole process.

Picture cutting enough individual parts for 50 spars, with each part being
reproduced in exact precision. By careful setup, (by one exacting craftsman)
you would produce parts at least as good as you could do, just making one.

Instead of jigging for one spar, a permanent steel jig could be set made that
would make the spar almost impossible to put together incorrectly.

Semi-skilled labor would be all that is needed to assemble the spar and glue it,
if they are taught and all of the parts fit right. I live in the furniture
belt, here in NC, and they do some pretty complicated assemblies; much more so
than a spar.

Granted, the spar being wrong is a lot more critical than some poorly assembled
furniture. Quality control would be important, but possible. It would be
advisable to test to destruction, a few at random, to verify correct assembly.
--
Jim in NC