slipper clutch do you mean for the main clutch???

I'm sure you know the info below , but here it goes.

All nitro cars/trucks have a standard clutch. usually it is two plastics levers that push out using centrifugal force and make contact with the clutch bell. the clutch bell the spins the spur gear.
during idle the clutch retracts and the clutch bell is then disengaged.

The slipper clutch is a disc that uses friction to allow the spur gear to "slip" a bit so you don't chew up the gears.

You will see this mostly on stadium truck.