Randy,
What type of RPM's are we looking at on a PA 65 side exahust, running a stock APC 12x6. Figure on say,10% nitro.

Thanks in advance.

Hi my friend.. I have no idea on that prop, It would be about the last thing I would ever recomend for a 65 PA. I would recomemnd trying props like 13.5 x 5 2 blades, 13 x 4.75 3 blades, Wide 13 x 4.5 2 blades, Wood 14 x 5 Pro Z cut to 13.5, 13 X 5 BYO . That is a good place to start
Do not worry about exact RPMs just set the needle for the fastest 4 cycle right before a 2 cycle and launch there. If it goes too slow..pitch up, if it goes to fast pitch down..DO NOT use the needle to try to control speed.
When in manouvers if it slows in the tops or looses any tension add nitro..if it speeds or winds up in manouvers subtract nitro.
Then use the venturie size and head shims last as tweeking-trimming tools. You will get the best run and performance using this than any other system I know.
By the way a 51 PA will easyily spin the apc 12 x 6 like nothing..

Let me know how it goes

Regards
Randy

I ran mine last season with a Zinger 12-6  choked down the venturi & set it at 8,500 RPM  real nice flying a 66 ounce Impact.

Wow...I gotta' wonder why anyone would want to do that?  You're sacraficing all the advantage of paying the price for a PA.  Why not just use a clunky old ST or the like!
Yes they will definitely run like that or just about any way you want to try but?.

Randy Cuberly