Calculation of propeller tip speed

I've gone through this before, but all my knowledge escapes me. There was a person on this forum that helped me determine the max propeller rpm to yield a tips not in excess of 85% of the speed of sound. Searching the posts hasn't come up with the post.

Thanks,
Chuck Gruby

Not sure if this is will give you are looking for, but here is Warp Drive's propeller tip speed calculator. JImChuk
www.warpdriveprops.com/propspd2.html

Thanks ever-so-much. That's exactly what I was looking for.