I see a lot of guys running 10" of pitch on their gassers for aerobatics (Extras, Caps, Yacks, 50cc, 80cc, 100cc), I think they run 10" of pitch because their motors are big and powerful and they feel it's the way to go, but I feel they would be better-off running a larger prop with less pitch, 8" even 6" of pitch, I say this because I have seen the benefits of larger props with less pitch on glow planes, larger props with less pitch pull better at low RPM and the plane is more stable in the air~ which is great for aerobatics, I have had planes twitch their tails or do other funny things~ but once I change to a larger prop with less pitch the problem goes away !! ,,,, on my Gee Bee Y I want speed, I don't care much about low speed performance, but I run a 20" prop because my cowl is so large, if my cowl was smaller I would run an 18x10 for more top-end speed,,,

Richard, if you want that Zero to go faster try an 18x12, that will get your motor's RPM down in it's power band and the plane will benefit from the extra 2" of pitch, and I'm also betting if you bought a 20x10 carbon you would get something around 7400,,, my friend put a carbon prop of the same size he had in wood on his old Sachs 4.2 (106" P47) and he gained 690 RPM, the plane was some 15MPH faster on it's top-end..

Jim