Centrifugal (automatic) clutch

Right slider = input power/speed
Left Slider = Forward/Reverse
A sort of reversal of what you'll find on model vehicles and mopeds/scooters (force is driven onto central cylinder rather than an outer bell or ring)
Installed on a simple buggy/chassis for demonstration purposes.
Added rough rev "needle" to show input rotational speed, "needle" hits a point until the clutch fully engages/locks then raises again, along with acceleration of vehicle. Derivatives allowed, please enjoy.