Hi
I made a garden ornament using a fan from a car. it was a one piece plastic molding with five blades and asymmetrically spaced, drove an old cycle dynamo and lit a couple of little bulbs, before the days of bright LEDs.
I never worried when the speed went stupid, decided if it was capable of 5000/6000 RPM on an engine a couple of thousand RPM or so no matter how noisy wasn't going to be a problem.
Brian