Yeah, I closely monitor my RPM. for instance, my OS 1.20 AX engines never ever are allowed to go above 10k. I turn a 15-10 prop with no problems and that pulls the plane along nicely. Peak RPM around 9800 with that prop. I also may use a 16-8 if I want a little more pull. That peaks just at 10k.

The smaller engines.. never above 11K or so. And, I always run them on the rich side of lean. I'd rather clean the oil off of the wing than flakes of metal. They fly just fine with that RPM range, with the proper prop, that is.

CGr.