Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Looking to fly. need speed. Have other dimensions

  1. Oct 20, 2014 #1
    Hey everyone,
    I have a theoretical problem. I have a box. Rounded off but not greatly aerodynamic. It is 800 kg including propulsion. I have wings with a max of 2.25m long and a max width of about 2m wide. This is the length of the box. I need to know how fast the box needs to go with those detentions to lift and fly. This is a simple thought experiment. I would love any help on the idea. Thanks.
     
  2. jcsd
  3. Oct 20, 2014 #2

    NTW

    User Avatar

    Just 'at eye', 300 km/h may be enough...

    Calculating it more properly is not too difficult. Assuming that only the wings provide the lift, and just for compensating the wight, you can solve for velocity the equation:

    Lift = 800 * 9,8 = 0,5 * v2* S + Cl * rho

    Where Cl is the coefficient of lift, that depends of the angle of attack and the wing section, but for a first approximation you can take Cl = 1,5. S is the surface of the wings and rho the air density. As the lift is in newtons, if you use S in square meters, and rho in kg/m3, you will get v in m/s.

    Happy flights...
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook