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Aerospace Calculating static thrust

  1. Aug 31, 2011 #1
    I want to make a quad rotor UAV. i studied a lot but i did not find how static thrust is being calculated. In physics forum i have found an equation which is given below but i can not understand what is 'frac' and 'rho'.
    Equation is:

    P = power (ft-lb/s or kWW)
    T = Thrust (lb or kN)
    D = Prop Diameter (ft or m)
    n = rotation speed (rev/s)
    c_P = Power coefficient
    c_T = Thrust coefficient


    c_P=\frac{P}{\rho n^3 D^5}

    c_T = \frac{T}{\rho n^2 D^4}
  2. jcsd
  3. Aug 31, 2011 #2


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    \frac is badly formed latex. If you provide a link to the earlier post, that may help someone interpret the formulas. rho is probably the density of the fluid in which the rotor or propeller is acting.
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