I agree with Evan, The problem that you may have is that the servo could be a little slow at times, depending on what you are doing with the heli. Hard 3D may not hold as well but if you are into FAI/big air flying, rolls and loops, tick tocks, it will be fine. Anything at .12 speed range and faster will be best. The 401 will actually work with most any servo from digital to analog.

Jim