ORIGINAL: ThumbSkull
ORIGINAL: 1QwkSport2.5r
The flywheel would have to be rather heavy (and probably large) to use alone, and if putting a sprocket on it to drive a separate propshaft and drive by belt or chain would need some careful and precise engineering of which I dont have the tools to do. Running a flywheel alone would be ideal, but it would need to be heavy - probably 2-3lbs or more to provide enough load to not grenade the conrod. Think Dynamometer here... The conrod is usually the first to go when doing a shaft run; which is essentially what one would be doing running an underweighted flywheel like what would be used in a car or truck.
I suppose a ''car'' jig using the standard car clutch and flywheel, and fashioning a spur gear setup to drive some sort of ''load'' would work. This is far more complicated than I would want to get into but it could be made to work.
I wouldn't want to be any where near 2-3 lbs spinning at 20-30k. That's a LOT of stored energy just waiting to find a weak point.
A flywheel alone will not limit the RPM's at all. A dyno is more than just a flywheel, there is a torque applied load.
Warnings made. Let the process of natural selection begin.
I know there is more than just a flywheel in a Dynamometer. I have seen a few R/C Car engine dyno's in action, and they use a flywheel that I estimate at 1-2lbs and its geared down so it isnt spinning as fast as the engine is.
Nonetheless, there is a way to do it safely.. Its just a matter of getting creative.