Sounds to me like you need to increase the gyro gain and trim out the radio the gain is the little screw pot on the side of the receiver module on the heli and the trim adjustments are the switches on the side and bottom of the sticks on the radio.I cannot tell you how much you need to do it is trial and error type thing you just have to try it.I had a Rotofly for about two weeks and got tired of messing with it I then purchased a Trex 450x and had much better luck with it.There is no such thing as flys right out of the box I have had to mess with every RTF I have ever had to get it to fly properly and there are a few.Just make small adjustments and remember what you did incase you have to undo it and do one adjustment at a time I would start with the gyro because that is the most important then work on trimming out the radio.