Yup... What 3DRomeo said. If you use 4mm carbon tubes it helps a lot. If you use "wrapped" carbon tubes it will almost elininate the problem, however the wrapped tubes are quite pricy! You can get carbon tubes at
www.nyblimp.com Using Depron instead of fan fold helps also, but it's a cost issue... 3 bucks for a plane that can do almost everything aint bad... Even with a bit of twist...
3Dfanatic - remember, these are copyrighted plans... Feel free to build a few for your buddies and charge them as you feel appropriate (time, materials). However, you may not produce these planes commercialy (ie advertising, etc.) Have fun with them though!!!!!!
Tim