This is going on a Yak 52 from nitro planes. http://www.nitroplanes.com/yak523d5056n.html
I am more of a hover high alpha guy but like to do tumbles on occasions.
I have the 17X10 on there now and it spins up ot 6000 rpms now. I was told by a person with the same motor that it spins a 14X8 at 12000 (not confirmed but I have no reason not to believe them).