On Wed, 31 Oct 2007 10:28:53 -0700, Bob Kuykendall
wrote:

On Oct 31, 10:02 am, Orval Fairbairn
wrote:

You should be able to find that information in the materials handbooks.

I would start with a Google search for "Forest Products Laboratory",
which is the central source of information on wood products. They test
materials and publish the results.

That's true as far as it goes. However, the design and development of
sport aircraft occasionally demands that one innovate beyond the
boundaries of what established laboratories and institutions have
deigned to test and approve.

Even fiberglass strength varies over quite a range depending on the
ratio of fiber to resin, fiber orienttion between layers, and type of
resin.

Plywood layups also vary some what.

Roger (K8RI)

Consider the practice of using cellulose fiber composite panels for
the reinforcement of truss junctions in chordwise wing members. First
developed in the 1930s, this practice was validated in a successful
glider design and is currently under evaluation for at least one light
sport aircraft.

However, it would never have seen the light of day of some poor guy
hadn't snipped a bunch of wing rib gussets out of cereal box cardboard
and tried them out. Necessity is the mother of invention. Theory often
follows practice.

Thanks, Bob K.