by David Lewis » Sat Sep 06, 2014 7:14 pm
When attaching the wing to the side of the fuse, the trick is to add joiners that are the same hardness as, and with the grain running perpendicular to, the fuse side and the root rib. I extend the end of the crosspiece near the wing LE out past the cabin side, and add a 3/32" square joiner near the wing TE. This precisely keys the wings into the fuse with equal incidence.
When you glue two pieces of wood together with the grain parallel, the joint is heavy and weak. Basically the wood peels away when you put any force on it. Cross grain joints are stronger.
Secondly, using a birch dowel for a joiner doesn't work well. A dowel is stiff and unyielding, so most of the loads get funnelled into the dowel, and these concentrated loads are transmitted into the soft balsa. Balsa joiners distribute the stress more evenly.
Last edited by
David Lewis on Sat Sep 13, 2014 8:43 pm, edited 2 times in total.