ummm.. im not into helis but my friend is kinda well hes a noob and he bought a ep concept the body thats yellow and looks like a bug. he says when he first got it that it flew good but I havent NEVER seen it fly. he said he crashed it once and it never flew properly again. he doesnt know what hes doing hes full of BS and hes very naive. he wont go on the net to find help so do you know whats wrong with his heli. when he just wants to go up it tries to tip over. and the instructions are in japanese.

If the blades are nicked you can have problems. Also your friend should check the blade tracking. Blades perfect, tracking perfect = good flight characteristics (most of the time). He can also check the cg (that should be checked after every crash).