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Can anyone confirm this equation? Prop. Thrust

  1. Feb 5, 2007 #1
    can anyone confirm this equation?? Prop. Thrust

    there are many websites that calculate propeller Thrust, and they never show any formulas for it... and i somehow manage to find the formula from NASA website, but when i compare the result with each other, i get totally different numbers...

    Thrust = (density)(pi)(radius of prop)^2(2)[(2Vk(RPM) + k(RPM^2)]

    where k is coefficient of efficiency of prop.
    V = speed, V=0 when static

    if i just work with the units only, i get the force unit no problem, but the result is way off from the number from websites..
    anyone know which one is correct?
  2. jcsd
  3. Feb 6, 2007 #2


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    Science Advisor

    You might want to try this one:

    [tex]T=P_{io}^{2/3}(2 \rho A)^{1/3}[/tex] where

    [tex]T[/tex] = thrust
    [tex]P_{io}[/tex] = (induced) power of the engine
    [tex]\rho[/tex] = density
    [tex]A[/tex] = propeller area
    Last edited: Feb 6, 2007
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