Hmmm... I was wrong. Your "ear guess" is spot on, though I think you're pulling my leg. Your prop speed right now is around .6 Mach, or 450 mph more or less. Of course, that's static and it unwinds in the air.

Anyway, my recommendation is still good. The Zinger props are a fairly light load; it will be interesting to see how that Zinger 20 x 6/10 works out.

AV8TOR