ORIGINAL: pelham
my engine is turning 10,000 rpm with the 12/8 prop. SUPERTIGRE SAID THIS IS NORMAL.
You won't get a lot of performance with a 12x8 prop in vertical. Put a 12x6 or 12x4 on it and you will see a large increase.
I have always liked the ST engines, but if you try to do the fun stuff with the wrong prop, you will be dissapointed with any engine you run. Your not going to get max RPM out of anything with an 8 pitch prop. There is no way!