Wild Bill
Well-Known Member
Doing some box spar testing/calculations..
after thinking some about typical box spar construction, I became concerned about the glue joint between the spruce spar caps and the outer shear webbing.
In a normal box spar with say 3mm (1/8") 3 ply plywood shear webs only the first ply is glued to the spar wood.
I may be overthinking it but to me it seems like it would be better to taper cut the edge of the spar and the face surface of the ply web so that all three plys are bonded to the spar.
Otherwise it looks like you are relying on the strength of the face layer itself and the strength of the glue between the plys to hold it all together.
after thinking some about typical box spar construction, I became concerned about the glue joint between the spruce spar caps and the outer shear webbing.
In a normal box spar with say 3mm (1/8") 3 ply plywood shear webs only the first ply is glued to the spar wood.
I may be overthinking it but to me it seems like it would be better to taper cut the edge of the spar and the face surface of the ply web so that all three plys are bonded to the spar.
Otherwise it looks like you are relying on the strength of the face layer itself and the strength of the glue between the plys to hold it all together.
