Hello everybody, I think the OP got some good answers and info now on a bit of a different side....I have said engine in a biplane and would like to "tone " it down. I am using an Xoar 11x6
now as I have a few for the other planes which are 4 cycles. But the ST45 is over powered to me and would like hopefully experienced help on the use of say a 12x4-5 prop on it. It's my Sportster
in my gallery if you need pic's I just found a prop at my local HS they are holding it .