My 110 turns the 16x8 at about 9.3k at which speed the engine is quite happy. I am running Wildcat 30% though, on lower nitro it would struggle a bit as I guess it likes to be mid 9ks as the 91 does. I'll be trying out a 15x9 tomorrow though to see if that is an improvement for F3a as I am going to use it as a spare model for competition flying as well as a 3D type plane.

I spoke briefly to Christophe at Sandown this year and he is using a 15x8 on about 23% nitro (I think, I don't recall exactly which fuel he was using). Interestingly, everything on his plane was as standard bar some minor work to get his pipe to fit. I am sure it was trimmed to perfection but it was illuminating to see just what this plane is capable of in the hands of a genius!