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Homework Help: Finding Lift Force - Glider Wing

  1. Oct 29, 2009 #1
    I am working on my semester project and have come across a hitch. I am trying to find the Lift Force of my wing using the following equation

    FL=CL P A (v2/2)

    FL is Lift Force
    CL is Coefficient of Lift (I think)
    P is the density of the fluid (Air)
    A is the Area
    V is Velocity

    The only portion I cannot find is Velocity. I cannot, for the life of me, figured out Velocity when given force and mass.

    I have a 3.33 lbf and a 27.999g aircraft.

    Can someone please help me.

    Equation so far:
  2. jcsd
  3. Oct 29, 2009 #2
    I found the equation for Horizontal Velocity. Here it is for anyone else who might be stuck in the same place.


    E is energy
    m is mass

    In my case Energy was elasticity since my glider was flung from a rubber band. So I had to find ft-lbf, then use different conversion factors to get to a suitable velocity unit.

    My work:

    VH=[tex]\sqrt{\left[\frac{2(4.1625)ft-lbf}{27.999g}\right]\left[\frac{453.6g}{1 lbm}\right]\left[32.2\frac{lbm-ft}{lbf-s}\right]}[/tex]

    Leaving me with Velocity in Ft/s

    VH= 65.899 ft/s

    Additional Information:

    I was given a chart, from whence I figured that 15 in displacement gave 3.33 lbf, and converted to ft-lbf, giving me my E.
    Last edited: Oct 29, 2009
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