Jim
I have a remington 38 CC engine that I use a 20/6 beechwood prop for pull, I have peak mine to 7,960 best I can get but plane pulls good and my angle at liftoff is about 20% don't want to stall it. It might take a little longer to get up there but doesn't take any time at all if you stall to crash it.
BOB
fair winds and lots of blue sky LETS JUMP