ORIGINAL: ameyam
Issue is couple of weeks back when I started I was thinking exactly the same. Hence I started wit a 14x4 and after I took off, we could hear the high pitched sound of the engine overrevving. My 14x6 is on the FS91SII so I put in a 14x8. Dont think that the prop will make that much difference. Remember, I have the very same problem with the 55ax before this and I used all props from 12x4 to 13x6 (12x4, 12x6, 12x8, 13x4, 13x6) but couldnt resolve it. Was using the same batch of fuel though
Ameyam
prop makes a HUGE DIFFERENCE try pulling a semi trailer with your car.....thats what you are doing to your plane engine....if a engine has too much load it overheats.....thats why we use trucks to pull trainers because they have bigger engines.....
thats wht a .75 engine should run on a 14x4 or 13x6...because it is in its powerband....like your car engine pulling your car and only your car.....
the sound you heard with the 14x4 was the engine getting into its powerband....not it overreveing (which you cant really do on a two stroke unless you have a 10x6 prop or somethine