His take on it is exactly that, it doesn't matter either way, but don't put a bolt through the glue line.
+++++++++++++++++++++++++++ This would otherwise be my reaction as well - but I am forced to give the matter more thought. My centre section spar caps comprise 6mm (1/4") laminations to allow the dihedral bend - so there is no way to avoid the WAF bolts intersecting glue lines. If I use the RR design WAF - all the bolts will intersect the same lamination. I plan to have a longer centre section, so the spar is substantially thinner (in front view) at the WAF location - not much room to move around. I opted for 1/4" laminations as I figured this would be about right to accommodate the dihedral bend. My first reaction on seeing this post was to consider thicker laminations and resort to steaming as a means of achieving the radius. My second reaction was to re-read all my material on glue joints. Every indication is that a properly done glue joint is as at least as strong as the host material. A scarf joint is allowed in a wing spar (cap) according to AC43 - at an angle similar to the minimum spec on grain run-out within wood, suggesting that a glue line is at least as strong as nature's own laminations (wood-grain) - is this not the very reason that a laminated beam is seen to be stronger than a single piece of lumber (of the same size and wood)? The topic should be a head up in other ways as well when we drill holes in the spars for various other reasons - this will influence the main undercarriage location (under the spar or in front of the spar) to avoid drilling even larger holes through the laminations. These holes offer an even greater moment arm than the WAF's. Steve J Zambia
