RE: Anyone got readings OS Fx 91?
OS-91 FX with pipe (Merker) on 18% synthetic/castor mix oil, 5% nitro:
APC 15-6 at 9400 rpm, 93 Db at 3 meters; great flying, but a little noisy!
APC 14-8 at 9100 rpm, 91 Db. Good flying
APC 14-10 at 8300 rpm, 89 Db at 3 meters; good for pattern flying, but "feels" slow (which it isn't)