ORIGINAL: Flyboy Dave
I'm gonna give my YS 63 powered Bobcat one more try with a Zinger 11-8 prop
and see what happens. I think it will have to spin about 11,000 to have a chance
at any decent performance....the 12-6 just didn't have any speed. [
]
FBD.
That's a theoretical maximum speed of around 83 mph, assuming no drag and no slip from the prop.
In the "real world (tm)", chances are you'll score around 70-75mph in level flight.
You might be better adviced to try a 9" or even 10" pitch -- although there comes a point where you'll actually go slower as you increase the prop pitch.