In article
,
cmyr wrote:

In my effort to learn/remember/practice correct building
procedures,I monitor several wood aircraft design sights. In the
emerauders group,much discussion about using a wingspar that was built
and purchased by another builder. The Emeraud spar consists of 2
laminated built ip beams,w ply intercoastals, and boxed front and rear
w/ply. The spar in question was made with vertical grain wood, and
laminated with the grain perpendicular relative to the wing chord, I
believe the spar caps and laminations should have grain approx.
parallel to the wing chord. If anyone has a definitive answer that may
even prevent an accident go yo yahoo groups,emerauders

The important item here is the orientation of the wood grains in the
spar caps. They MUST be parallel in the spanwise direction. The spar
webs are there primarily to absorb shear loads, where 45 degree plywood
would be optimum. I really don't think that the orientation of the spar
webs is critical, because their shear stress is far less than their
strength.

SEE:
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