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Old 08-23-2008, 09:34 PM
Gray Beard
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Join Date: Apr 2003
Location: Hemderson, NV
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Default RE: os 91 on a spitfire h9

Rule of thumb, longer prop smaller pitch= slower speed but more torque or pull. Shorter prop with A bigger pitch= more speed. You just have to try props until one of them works the way YOU the pilot likes. Just make sure you keep your four strokes in there working RPM range so you don't float the valves. Finding that special prop is A lot of work and fun.