Mcm don't get the eagle tree or any other heli gyro. Here's why, if you tank moves so the elevation servo can't keep the barrel level the gyro gets confused and doesn't centre properly. Also if your movement is very slow then they struggle to pick it up. However I have a sub with an auto leveller and this seems to work much better, it works when the sub is stationary and always centres properly. A decent pitch controller costs about £50 (check out the AL5). I've been through trying serveral heli gyros and found none I was happy with.