You guys discussing props/rpm has got me wondering if the 16x6 on my 1.50 may be contributing to the trouble Ive been having tuning it.It is on a CG Ultimate.I have one on a CG Extra as well.It is a lower time engine than the one on the Ulti so it is still rich and I havent noticed the tuning trouble yet(even rich it is more than enough for the plane).I know prop size opinions vary,but would be interested in some of you guys' thoughts.