APC also has a 9x3 N combat prop listed, apperently a narrow blade, possibly to turn up the rpm a little bit over the 9030 combat prop? Ive been running the 9x4 mas but im going to run some test before nats with the 9x3apc and see how i like those.

I run the 9x5 apc on my jett 30 , the 9x4 turned a few more rpm but seemed slower in the air. I believe that motor likes to be tuned to pull the prop at around 18k, to small and you get out of the range the pipe is tuned for... I flew it in open C last year, wicked fast...