I've posted a couple of drawings on my blog
(bobhooversblog.blogspot.com). They should be on the top of the queue
so you won't have any trouble finding them. There's still a couple to
go, plus the text but these will give you the idea of what's involved.

While the wing is held in position by struts, stays or guy-wires, the
wing itself depends upon its internal structure to keep from
collapsing. As you can see, triangulated trusses hold the spars apart
and prevent the structure from collapsing.

Our goal is to come up with an internal structure that is strong
enough to withstand the maximum load while being as light as
possible. Since the wing is going to be built by people having no
prior experience, the principles embodied in the structure must be
easily understood and easily duplicated, since it's most likely that
more than one person will be involved in the construction. Finally,
the method must be inexpensive.

We will probably be using the Ison-Type truss, the drawing of which is
not yet posted. But it was necessary to post other types of wing-spar
trussing for comparison. Even then, there are literally dozens of
other methods of accomplishing this particular task. The reason I've
posted these particular methods is because they are the ones most
APPROPRIATE for this particular task.

-R.S.Hoover