Well, I went with the 15x6 APC and am happy for it. My H9 P-47 has more vertical, sounds better (not screaming anymore), and actually slows down enough to land the danged thing without nosing it over. I tached it today and at full throttle and still running fairly rich I'm getting 9100. She's idling around 2100 and purrs like a kitten. I use 10% nitro with an 18% Synth/castro oil mix.

Dave