MA props to flexable, have low pitch that stated and have a poor airfoil. good fow low rpm trainers and tow planes.

your 11x8 prop is close to a APC 11x6 prop in pitch and a 11X5 by flight performance.

I have done some Telemetry testing and the MA i had to go up 2-3 pitch sizes for the same flight speed.

I also found out that 17,000 on a apc 11" prop they start get that super sonic howl/zing to them. i would never run a MA past 12,000 on the ground in the 10-11" sizes 11,000 on the 12" props and so on.