Servo rotation

[MichaelC]

Hi all,

Just want to post my servo rotation installation in my ZTZ. The HL rotation unit was always a sore point for me as it is noisy, doesn't run smoothly. When I acquired my two modern tanks, with the larger turret and turret ring, and the fact that they are suppose to spin significantly faster makes the HL unit completely obsolete. I have tried using faster motors but what it gives up in torque makes it even worse on the larger turrets. For WWII era tanks, I have try using two HL units to compensate for the lack of torque in the gear set (My Maus uses two HL units to get the require torque to turn the extra heavy reasin turret).

First of all you will need a continuous rotation servo. There are only couple of them stock (One from Futaba and one from HiTec) that I know of. There are also a number of DIY videos on youtube on how to convert a run of the mills 60/90 degress servo to continuous rotation if you are handy. The price for the HiTec on eBay was about the same as a regular servo so I saved myself some grief and bought two of them instead.

The first thing you need to do is to remove the final gear from the HL rotation unit and mount it onto the servo. I left the pull "circle" on the servo and mounted the gear directly on top and also put in a stop screw so there is no movement between the two:

Then I realized that there is couple of ways to install the replacement servo rotation unit:
In the original HL position which can be mounted next to the smoker unit. You will have to remove the battery compartment since the servo needs the vertical space

On the side of the upper hull but there is no easy way of mounting it.

On the lower hull which requires some alignment when you put the upper and lower hull together.

I ended up with mounting it on the lower hull as I realized that by mounting it on the lower hull, the moment you separate the upper and lower, your turret is completely free to move. This installation actually is identical to how a real tank's rotation would work as the turret usually just sits on top of the rotational unit. I really like the idea that the turret is no longer fixed to the upper hull and I always hate the clutch on the HL unit so this really kills two birds with one stone. The only trick to this mounting is that you will need to align the cog ring so that you know where the servo should be positioned. I basically put the hull together, hot glue the cog ring to the lower hull so I know it is exact position and then mount the servo on the lower accordingly.

Final picture (I have to clear some lower hull side wall to fit the servo gears).

The differnce I found is that it is much smoother, faster(still not as fast as I would like but much better than HL), more responsive and you can also program this on a pot/knob on your radio as well as the usual left right on the left stick which makes it a little more interesting.

MichaelC.