SheldonYoung,

Your point about the orientation of the grain is incorrect. As the name of shear webs suggests, they are intended to bear a shear load. Specifically, they keep the upper and lower spar members from moving relative to each other in the spanwise direction. For a shear load, wood is strongest across its grain, which is why shear webs are oriented with their grain vertical.

GeraldO,

There certainly can be a tendency for the upper and lower spar members to move closer together when the wing bears a bending load, but it is not true that the members can't move relative to each other in a spanwise direction without being compressed together. In any case, wood is very strong in compression in the direction of its grain. Shear webs with vertically oriented grain, and glued to the back ( or front ) of the spar members will do an excellent job of bearing the shear loads and the compression ( & tension ) loads that result from a bending load on the wing. The superiority & simplicity of the lap joint make it very easy to realize those benefits. Moving the shear webbing between the upper and lower spar members would not meaningfully improve its ability to bear the compressive loads, but would degrade its ability to bear the shear load, which is more important.

I don't know about the superiority of your proposed 90 deg. laminated shear webs, but on a strength-to-weight basis I am a bit dubious. Wood shear webs with vertical grain are already making excellent use of the wood's shear and compression strength, and the small gap between the upper and lower spar members virtually eliminates buckling as a concern.

The easy way still seems best to me.

banktoturn