I bought 2 of the 3Dfoamy Superxtras the plane is mainly 3mm foam corescovered with 1mm foam skins.I'm stuck at one point and that's putting in the wing's carbon fiber rod.The spar slot is cut bowed so you have to bow the carbon spar to get in the the spar slots but here's the problem.The wing warps when you put the spar in,I tried a balsa square spar and that corrected the problem and I lost close to an ounce of weight.

If I had a square carbon rod,or one with a flat side that would fix it also.

Any suggestions are welcome.</p>