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dmaher

Flying an a/c with varibale pitch propeller

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Hi,when flying an aircraft (e.g. the SF-260) with variable pitch propeller I'm allways uncertain of what to do with the propeller pitch lever. Or more exactly: how to interoperate propeller pitch (~RPM) with the throttle.Can someone give me a hint of how to use propeller pitch and throttle during the various phases of a flight (TO, climb, cruise, descend and landing)?Thanks for any help, Thomas

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>Hi, >>when flying an aircraft (e.g. the SF-260) with variable >pitch propeller I'm allways uncertain of what to do with the >propeller pitch lever. Or more exactly: how to interoperate >propeller pitch (~RPM) with the throttle. >Can someone give me a hint of how to use propeller pitch and >throttle during the various phases of a flight (TO, climb, >cruise, descend and landing)? >>Thanks for any help, >> Thomas Think of prop pitch as the gear shift on a manual transmission. With the least angle of attack the prop at max rpm (lever/knob all the way in), it's like first gear allowing the engine to deliver max power but not the best fuel efficiency. This is what you use for climbing and is set again during the ealy stages of approach to allow maximum vertrical manuevering.As you start "cruise climbing", you ease the knob back to allow slightly less rpm than redline where you don't wish to stay too long to minimize prop stress.At stabilized altitude you pull back the prop further to recommended cruise settings, for many GA single engines at about 2300 if not declared or available in an aircraft manual to get along with manifold pressure a 75% economy cruise power.I noticed dividing the cruise rpm by 100 gives the approximate MP to maintain withg throttle. I frequently use 2300 rpm cruise maintaining 23 inches MP. Don't forget to increase/decrease throttle as you climb/descend to maintain MP as altitude and barometric pressure change. Consider a 1 inch drop per thousand feet up that you increase throttle to restore your desired setting as you climb.In addition, I can recall from my real aircraft single engine lessons quite some time ago, the acronym GUMPF meaning Fuel (Gas) to most full tank, Undercarriage (Gear) down and locked, Mixture rich (unless at very high landing strips or high density altitudes to keep the engine cool and most power if needed, Prop rpm full (in) for max manueverability especially if sudden climb is needed at max power, and Flap setting for pattern entry all to be set on entering pattern or Initial Approach Fix and Final Approach Fix as necessary.Hope this helps and I've recalled everything correctly.

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Hey Thomas,Just one thought to add...and it's a common misconception :-hmmmMost variable pitch propellers on GA aircraft are constant speed propellers. This means the pilot selects an RMP and a propeller governor regulates pitch to maintain it. So when you move the propeller lever on the SF-260 you are not directly manipulating propeller pitch. You

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