ORIGINAL: Cyclic Hardover
ORIGINAL: ClemenTang
try a 8x10 prop. You can mod the engine but otherwise you shouldn't be looking at top rpm but top hp, beyond that torque decreases too quick (i.e. high rpm only achieved with a small prop) and you're better off swinging a prop with higher pitch at lower rpm.
Clement
What he said.
Huh? You don't understand my Chinglish or have different opinion?
I think over-revving an engine only results in excessive wear and doesn't help in achieving top speed, rather use a prop with higher pitch much like going to 5th gear. The result of highest product of rpm x torque (i.e. hp) can achieve higher speed with a high pitch prop than over-revving a low pitch prop. Of course if you can pipe or mod an engine to rev faster without excessive decrease in torque then you have a new high in hp. The original poster is pushing his engine to rev beyond the manual's stated maximum (13000) and I think max hp occurs somewhere around 12000, and I believe 8x10@12000 may go faster than 9x7@13270.
Clement