ORIGINAL: Dr1Driver
It's a typical Duracrap. [X(] It's heavy, has a high wing loading and may be underpowered. You don't say what engine you have in it. All these things will cause the symptoms you describe. It may very well be tail-heavy also. Balance it approximately 25% of the wind chord back from the LE of the wing.
Good luck with it.
Dr.1
I 100% disagree with this. I fly teh Durastik and its the best plane I've ever had. It flies right where you point it and has no control problems. Yeah it has a little higher landing speed, but that just makes it that much more fun to land. Unless you have flown one yourself, you have no room to talk. Lets see your balsa plane have a radio failure, hit a tree, and be ready to fly the next day.