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  1. #1
    Member crashxx's Avatar
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    RPM calculations with pitch change.

    Is there a formula or "rule of thumb" to calculate RPM changes when changing pitch on the same prop? Example: If I'm running a 27p Bravo 1 XS @ 5600 RPM and go to a 25p Bravo 1 XS, can I estimate the RPM change?
    2003 Ranger 521VX
    2003 Mercury 250XS S# 0T652530

  2. Moderator 21XDC's Avatar
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    #2
    400 ish difference at the same speed. If you gain speed you may see more.

    Marks Props 317-398-9294, 1850 East 225 South, Shelbyville, Indiana 46176 propellerman59@gmail.com http://www.marksprops.com/index.html

  3. Member crashxx's Avatar
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    #3
    Ok, is that 200 per 1" of pitch so from a 27" to 25" it would be about 400?
    2003 Ranger 521VX
    2003 Mercury 250XS S# 0T652530

  4. Moderator 21XDC's Avatar
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    #4
    Yes. There are variables. Not every propeller is created equally.

    Marks Props 317-398-9294, 1850 East 225 South, Shelbyville, Indiana 46176 propellerman59@gmail.com http://www.marksprops.com/index.html

  5. Member crashxx's Avatar
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    #5
    Great, thank you for the info.
    2003 Ranger 521VX
    2003 Mercury 250XS S# 0T652530

  6. Member
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    #6
    Mercury website has a prop selector page that will tell you speed and rpms if you already have a known rpm/pitch and speed on current prop setup

  7. Banned
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    Hazard, Ky
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    #7
    It's 150-200rpms for 1" of pitch depending on if the prop's have similar slip. There's so many different variables it's hard to put an exact number on it.

  8. Member crashxx's Avatar
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    #8
    Thanks for the info!
    2003 Ranger 521VX
    2003 Mercury 250XS S# 0T652530