I have seen all the speed warnings. I have a Futaba 9 CAPS. I thought I might just reduce the throttle travel a bit if necessary. This would prevent accidental over accelleration.I am planning to try a 15" prop too. I don't want a prop so large that the engine suffers. It seems to really like the 14 x 6 I am using on my Stik. I am thinking the APC 15 x 4W might be a good match for the UCD.