The second design was simplified so that more members could build them. It uses a geared motor to directly rotate the upper plate. It only has two limit switches fitted, equipped with diodes to stop the turret if it attempts to drive beyond it's stops. The turret can be stopped at any position, as well as at it's end stops. The offset gearbox casing in red, provides the cam effect which engages the microswitches.
The limitation of this system, as previously discussed, is that on any angle of traverse that is not 90 degrees to port or starboard, the fore and aft turrets are pointing in different directions.
We also have a variation on this version driven by 1/4 scale servos. These have had to be fitted with a rubber shock absorber in the drive train, otherwise we run the risk of stripping the gears when using the pyrotechnic effects. These were built before Actions Servo Morph was introduced. We have yet to marry up the servo driven units to some of these, so cannot comment on their suitability.
As I said previously, these units are not the latest tech, but hopefully something in their design may help with the hardware side of this project.