On 7/8/2021 8:06 AM, danrh...@gmail.com wrote:
I am not sure why this never occurred to me when I was flying KR, maybe the
cost.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
When it comes to props Ed Sterba props are hard to beat, cost and
performance.
I'm running a Sterba 60" prop that started life with 68" pitch. After Ed
modified it I suspect it is still close to that pitch.
68" X 2450 rpm = 166,600"s X 60 minutes = 9,996,000"s / 12"s = 833,000
feet / 5280 = 157.7 mph. In level cruise at 2450 rpm I indicate 153 mph
so the prop is running close to 100 percent efficiency. I asked Ed to
pitch to a 64" for more rpm but I couldn't tell much difference after
the modification so I suspect it to be in the 66" range so it is as
efficient as it can get. I trust my indicated ASI to be within just a
couple mph of actual.
The FAA recommends 8 to 9 inches of prop ground clearance so you could
maybe run longer props on the tri-gear and conventional gear and a 3
inch longer gear leg would get you a 6" longer prop. Marty Roberts ran a
60" prop on his KR with 24 inch legs but then Marty seemed to do things
that seemed humanly impossible like pulling 6 G's in a 765 pound (empty)
KR, ripping the baggage shelf loose and falling on the elevator cables,
then landing and heading for the beer cooler. I sure miss
Marty..............
Larry Flesner
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