Controlling the linear pots of an RC transmitter from Arduino

The premise here is that when the captain calls for 1/3rd speed ahead, an enlisted man pulls a Telegraph lever to point to 1/3 ahead. The guys in the engine room see this and change the engine speed. They answer back by moving another Telegraph to indicate 1/3 ahead. This is seen by the bridge crew, and somebody says "engine room answers one third ahead, sir."

So we are sorta trying to simulate this. I might even decide to have a servo move an analog indicator like a Telegraph.

The electronics in the ship model will all be standard rc parts. There is a receiver, 2 esc's or a dual esc, a servo for the rudder, and 2 ungeared motors, one for each prop.

I need all interaction to happen in transmitter so that I can drive indicators and such. I want to slowly change the speed of the motors.