Section under wing building. I am planning on replacing the 1/8" birch ply & 1/4" balsa rear spar with a 1/2" balsa spar the entire length of the wing. This adds 1/8" to the wing. I will add balsa strip to the 1/2" rear spar at the root end where the small foam section is glued on. I am also going with triangle balsa stock for the aileron leading edge. By using all the above I can use the aileron as is without cutting. This would add I beleive 3/8" to the width of the wing.

I also built up main spars using 1/8 x 1/4 spruce top and bottom and 1/8 x 6" balsa sheet grain running vertically in between. It was easy to do. I also have replaced the 1/8 birch ply fuse sides with 1/8 lite ply. I have a digital scale and by replacing the above mentioned birch I cut off 14 oz. of weight! I am planning on doing this to the main stub spar also. All doublers and triplers I will leave as Birch ply. I also plan on replacing the Formers 1,2 & 3 with lit ply! I plan on using 1/4 balsa triangle stock on all formers where they meet the fuse sides. I am still going over plans and possibly will change the motor box.