ORIGINAL: ErikElvis
Harry you are right. Im pulling about 9600 with the 13x9. But im not sure the engine really likes the prop. Think trying a 12X10-11 would do any harm?
Erik, 9600 static is a good zone for the .91 surpass to be. Did you fly her with this prop? It should unload quite a bit (maybe 800 - 1000 rpm?) once airborne and on-song if the airframe is reasonably slick, which I would imagine is the case with the Minnow.
A 12 x 11 of 12 x 12 won't do any harm either and should be tried at least. As long as the static rpm are around 9300 thru about 10K you'll be fine. The Surpass .91 is a very forgiving, adaptable powerplant.