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Old 10-14-2017, 05:32 PM   #26
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I found a Looooooooong list of all Lycoming dash numbers and yes several were made for fixed pitch. It also verifies that the different counterweights were designed for different type CS propellers.

http://www.meyette.us/LycomingEngineNumbers.htm

What is not said or clear is if these "fixed pitch" engines had counterweights or what would be the effect if any of running a counterweighted engine with various FP propellers?

Jack


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Old 10-14-2017, 06:27 PM   #27
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The TCDS for the prop states which engine/counterweight configurations are compatible.
Also don't forget about Prince Propellors.
My buddy has one on his Cassutt-racer, I went out to Reno with him this year where he took second in the silver with a $3,000 plane.
Long story short, he was pulling an amazing hole shot on every start and his top end was still very competitive even though the prop (as good as it was) missed our preferred RPM range by almost 900rpm (low).
He was turning 3600 and wants to run 4500.
Prince makes a great prop for less $$$$ than Catto.


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Old 10-15-2017, 02:52 AM   #28
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Crank, that's my point. There is nothing about running a wood or composite prop on any of the counterweight setups. If the crank is weighted to offset a heavy prop and one runs a light prop is that bad? I'd think there would be a optimum counterweight setup for a light prop. (I'm guessing Lycoming agrees as they weighted the crank for different props from the factory)
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Old 10-15-2017, 02:27 PM   #29
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It's more about harmonics the weight. I think the question should be if a prop that is resonate frequency tolerant ( wood) then is there any need for counter weights at all.
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Old 10-15-2017, 07:25 PM   #30
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Engine guru at Midwest Aircraft told me the counterweights are to protect the prop not the crank. A wood or composite prop doesn't have the resonant vibration of a metal prop so counterweights won't have anything to dampen in that case. They won't hurt anything but they are kind of redundant.
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Old 10-15-2017, 11:05 PM   #31
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I may talk to my engine man about leaving them out. It's another ten pounds shed.


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