How to make s spinning propeller that can be controlled with Rigid Body World speed setting


Possibly a noob question but did not find a solution to this anywhere (probably it is very obvious):

I have animated a bone with keyframes to rotate and I have parented that with a propeller to make a cool propeller that rotates. However right after doing this I realized that I want to control the speed of rotation with Rigid Body World speed setting. How do I do this, or is there a better way to make the propeller rotate that allows me to use Rigid Body World speed setting?

Thank you in advance

Just to clarify more:, I want to make a fluid simulation with bullet-time effect and for this I need some help with this. Keyframe animation does not seem to work well in this case (?).