Ijust got two new mini RChelicopters. They're pretty cool i don't know what models they are right now but i could easily go look. But i have a problem with one of them. It doesnt stay still, I go to lift it without rotating it at all and it goes crazy. I don't know what is wrong, i haven't crashed it or anything. If any one knows what's wrong please help.

The other one works fine and i can fly it great, Ilift it and stop it from spinning with the left turn right turn buttons and then when its steady i can fly it around every where. But the other one, the broken one seems unbalanced or something and wobbles uncontrolably until it falls.