Mike, The picture of this honeycombed wing shows a spar along the back of the wing between the honeycomb and aileron line that is not shown on the wing plan that you sent me a pdf file of. Is this optional or should it be added to reinforce the honeycombed tip? If I need to add it, what material should I use- spruce, balsa or lite ply?, and can you give the the length measurement.? Thanks,

George