I tried a mini servo in my Pershing for ellevation but it was not strong enough to raise the gun properly. It had 17in . pounds of torque. you qould think that that would be plenty but it was not. so i used a full size servo and mounted it behind the recoil unit with a doubled up servo arem. I also made a track that mounted to the recoil unit for the arm to ride in. i used the small ball fitting for the connection. i also took the plastic ball mount adapter and cut the threaded part of to make basically a round bushing that ran inside the track for a smoother operation. It works great. <div> The H.E.A.T. web site has a whole tutorial on how to use a servo. the mountings are going to be up to you to make as each tank will need to be done a little different. It depends on how much space you have between the recoil unit and the turret side wall. I will try to get some pics of my set up to give you an idea of what it takes to do this. </div><div> Eliminating the clutch gear also helps. you can glue, heat weld or eyxy the clutch. i just use the blue gears from the Tamiya small project gear boxes to get the gears.</div>