Originally Posted by aeronca
I beefed up the wing spar by sliding and gluing a 4mm carbon tube (.188" from Tower Hobbies, actually) inside the stock tube. The assembelage is MUCH more rigid but with still a very slight flex. I don' think it will ever break!
That may be the best solution. I CA'd these strips in and the wings are like concrete. There's no flex at all. The plane is light enough that I'm not worried, but this would not be good on, say, full-scale for sure.