Larger props turning slower are more efficent than smaller one screaming away thrust is what counts also the larger ones get well
beyond the fus into "clean air" less noise less fuel wear factor way down prop speeds on full scale planes "slow" 1800 -2200' I think
even most 4 strk glow engines run at 10K or less again big props' also our gas engines 6800 to 7500 or so granted you have
your screaming jetts and rossi but for 90% of us we do not use them since we are flying sport ,, acrobatics,scale and 3D,
this where diesel really stand out
Of course they are some high speed diesels russian team race, paw has some tuned small diesels but at least for me a modern
2 strk conversion fills the bill quite nicely along with enyas new releases for most of us that use this post nothing new just hope
this gives a little info to the folks who never tried it or had questions about it martin