Unsolved How to spin a prop at a constant speed

I need help getting a fan to spin at a constant speed when the car's ignition is on.
is there already a function that does this in the game? if not could someone make one for me? (i don't know lua)

 

what fan? the fan that cools a radiator or the fans in the bus?

 

it's a fan for an AC condenser. but that's not relevant to my question I just want to know how to make a prop spin at a constant speed (so not using rpmspin or similar functions)

 

I'm sorry I don't know how to help