a 12-6 will NOT degrade an engines performance whatsoever. On my .46 I sling a 12 1/4 - 3 3/4 and the engine is running in a safe RPM range, it also alows for UNLIMITED vertical and will out climb ANY other prop in its class. Ask ANY great pilot that flies 3D what prop he runs on a .46 motor and 9 out of 10 will tell you a 12-6 or a 12 1/4 - 3 3/4 (generally an APC wide blade, but it doesnt have to be). This is the size prop that I run and it will hover the mess out of my airplane. I will put my prop up against an 11-6 anyday in a hovering and vertical contest[img]i/expressions/face-icon-small-smile.gif[/img]

On a .61 I run a 13-4W