📡 Servo
The motor-and-gear unit that turns a channel's signal into physical movement — steering the front wheels, working a plane's control surface, moving a boat's rudder.
What it actually does
The servo is the small geared motor that turns your steering. It takes the position signal from the receiver and holds the wheels exactly where you asked, against everything the surface is trying to do to them — which is why it is one of the components most worth upgrading.
In practice
Servos are compared on torque, usually in kg-cm, and speed, in seconds per 60 degrees. Torque is the ability to hold the wheels where you put them under load; speed is how fast it gets there. Metal gears survive impacts that strip plastic ones, and a waterproof case matters if you run in wet or snow.
Worth knowing
Never force the steering by hand with the servo powered and connected — that is a quick way to strip a gear. Check servo horn screws periodically; a loose horn feels exactly like a failing servo.