REALLY good numbers.
..Gotta wonder how you're clocking the speed...We fly Giant Scale racers...Our very close speed@rpm numbers are rpm x pitch x .00095 = speed in mph...We usually deduct 2 or 3% for drag, depends on the airframe...
Our Giant Scale unlimited planes turn a 27 pitch prop at 9400 rpm...9400 x 27 x .00095 = 241 mph. Mulitple Radar guns show 234 mph, so the drag % is about 3%...
The Sundowners run a 17 x 12 prop about 8500 rpm...12 x 8500 x .00095 = 96 mph, pretty close to the radar speed.....
A 6 pitch prop at 10,000 would be 57 mph...An 8 pitch @ 10000 is 78.4....
The GT80 twins turn a n18 pitch prop at 11,500....18 x 11,500 x .00095 is 196 mph, radar about 190....
The ThrustHP chart shows 51 mph for a 6 pitch at 9000 rpm....
That chart pretty much agrees with the above numbers....
Looks like the OS 1.60 using my numbers was turning the 18-6 about 17,000.. A Secret weapon..My Chung Yang 29 strokers and Zenoah G26s turn a 16-8 Mejlik about 9800...I wonder how fast that would be ?????