I've read some of the threads that cover using servos as recoil units. Is the only way they are used is in a channel coupling mode?

Has anyone semi 'hacked' a servo to use it as a small gear motor directly without a control board to be controlled by a TBU, Clark or any other BU?
( by semi hacked I mean without an small external pot needed to center the unit to be used with a radio system.)

Just curious if it's been done.

Jerry