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How would you determine the Lift(thrust) force of a Helicopter in hover

  1. Feb 23, 2007 #1
    I know the lift force equation is .5*rho*V^2*Area*Coefficient. But I was wondering in the real world how would you measure the lift force? I hope they don't just plug the values for the equations.
  2. jcsd
  3. Feb 23, 2007 #2


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    Gold Member

    The easiest way is to weigh the helicopter. If it's hovering, the lift force equals the weight.
  4. Feb 23, 2007 #3
    I was wondering like if you are building your own helicopter what would someone use to test the amount of thrust produced by the rotor?
  5. Feb 23, 2007 #4
    i wonder if bernouilli's equation can be put to use in this case. i know that it can be used when there is wind driving a wind turbine. it should work here
  6. Feb 23, 2007 #5
    I guess you can use Bernoulli to calculate the change in pressure helicopter.
  7. Feb 23, 2007 #6
    i think u can find the maximum power yield by zeroing the velocity at the exit
  8. Feb 23, 2007 #7
    yeah we can find the maximum power yield by zeroing the velocity at the exit

    if smbody interested , i caN upload a book on the aerodynamic of the helicopter.
    tel me if interested
  9. Feb 23, 2007 #8
    That would be great.
  10. Feb 23, 2007 #9
    I will try tmrow , i willl send u a link on rapidshare or mhid.net;
    ur welcome and hope that will be helpful
  11. Feb 23, 2007 #10
    definitely interested in that:)
  12. Feb 23, 2007 #11


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    You could do this simply with a spring scale and something to constrain the rotor group to the scale and something to drive it. It is even easier if you have a strain gauge based force transducer because then there would be no axial movement due to the thrust.

    In regards to the original question, the airfoils and rotors are well known throughout the flight envelope from wind tunnel testing. The calculations involve effects of trailing blades, etc... Of course, the calculations are always compared to actual testing.
    Last edited: Feb 23, 2007
  13. Feb 23, 2007 #12


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    Staff: Mentor

    To test it, you mount it on a test rig and measure the forces.
  14. Feb 24, 2007 #13
    scale down models and wind tunnels are to measure the force.
  15. Feb 24, 2007 #14
    this si the link uploaded in the rapidshare

    Hope that it is helpful

    Attached Files:

  16. Feb 24, 2007 #15
  17. Feb 24, 2007 #16
  18. Feb 24, 2007 #17
  19. Feb 24, 2007 #18
    Thanks a lot
  20. Nov 20, 2011 #19
    heyy there can u pls re-upload the file for me pls? i couldnt download the file. actually im new here. so pls help to guide me :) thanks in advance eh
  21. Nov 22, 2011 #20


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    Science Advisor
    Homework Helper

    Look at the dates on the posts. This thread has been dead for more than 4 years. It's not surprising the links don't work any more.
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