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Some Help with Propellers

  1. Jun 11, 2007 #1
    Does anybody here knows how can i calculate (or plot) the Thrust as an airspeed function?

    I guess it'd be something related with Pitch, Diameter, HP, air density...

    Or... a way to calculate RPM as a pitch, diameter and power function?

  2. jcsd
  3. Jun 11, 2007 #2


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    Gold Member

    Welcome to PF, Cerpin. I can't help with this, but others here can. Be patient and they shall appear. :biggrin:
    Last edited: Jun 11, 2007
  4. Jun 11, 2007 #3

  5. Jun 13, 2007 #4


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    Complicated question. The simple answer is, for a
    standard propepper which has been empirically analyzed,
    look up the values in a table and then your equation is just
    interpolation or curve fitting of the actual measured values
    applicable to your particular propeller and circumstances.

    For more analytical, theoretical, or mathematical models
    that try to explain ab initio what effect airspeed has on
    thrust of a given propeller, see the following for starters;
    it's interesting to see what simplifications are made in
    various models, as well as how the model results compare
    with empirical data.

  6. Jun 13, 2007 #5


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    Relevant to your second question about RPM vs pitch,
    diameter, power, see also:

    Here's another report from the NACA server that discusses relations between airspeed, thrust, rpm, and engine power:

    NACA Technical Note 237
    Propeller Design: A Simple System Based on Model Propeller Test Data III
    Fred E. Weick
    May 1927
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