Outboard flaps are done. Used construction technique taken from wings. Front is a D-box with shear webbing on top/bottom spars. Cap strips on top and bottom of ribs. For the top sheeting, used two layers of 1/16" balsa sheet, forming a laminate. These flaps are very stiff.
Looking forward to finishing the aileron mounts, finish sanding and then covering the these outer control surface in Solartex.