super sonic on a full scale or model
a 10 inch prop would need to turn 26080rpm at 80degree F. for the tip to reach mach 1
so we never get close to those kind of numbers in fact we can't even turn or little 2 blades to the max
max blade effeiciency of .88-.92 mach
example at 80degrees F.
10 inch 23500 is mach .901 no regular ole 46 will to that
10 inch at say 11000 rpm is mach .42

here's a link to a prop mach calc if anyone wants to play around

[link]http://www.pponk.com/HTML%20PAGES/propcalc.html[/link]