My heli will do the same thing after about 5 minutes. The tail will be solid at the beginning of the flight then I start having to chase it around. I belive that it has to do with the fact that as your battery pack wears down it is also dropping in voltage so the tail motor is spinning slower than when you first started and trimed it. I just reach down and adjust the trim a couple of times during each flight to compensate for the tail drifting. I guess that you could add a gyro to stop this but I probably won't. I promised myself I would keep it stock and learn how to fly. Then I will upgrade to a T-Rex 450 SE. The cost of the T-Rex is not scaring me right now, I have that kind of money in 2 of my RC trucks, I just can't imagine crashing something that expensive as often as I have been crashing my Axe. Maybe in 4 or 5 months I will take the plunge. It all depends on my learning curve.

My Flight Update: I was able to fly 3 full lipo packs out yesterday after work without crashing!! I am getting better at forward flight and am still practicing flying back and forth about 40' in my back yard. My transitions are slowly getting smoother but the heli still gets squirly every now and then and I have stabilize it in a hover and then start my routine over again. I then like to finsh the last minute or two of each pack with some nose in hovering at a low altitude of 2-3'. I don't think that this is too bad since I just ditched the training gear about 3 weeks ago.

Good luck and remember to have fun! After all this is a hobby.