Unsolved Lift and Drag simulation

Discussion in 'Mod Support' started by aljowen, Jan 10, 2021.

  1. aljowen

    aljowen
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    Joined:
    Oct 21, 2012
    Messages:
    1,659
    I have been trying to fix the aero for the R20 to improve stability. I have started looking at the ETKC to better understand what mine should look like, and its left me a little confused.

    screenshot_2021-01-10_12-33-30.png screenshot_2021-01-10_12-46-51.png

    Red is clearly drag, I assume yellow is the coef, and blue is lift.

    But I am struggling to make sense of it, since the lines don't point in the directions that I would expect.

    It makes sense that the rear slope would generate lift (as shown by the blue lines), but the base of the windscreen certainly shouldn't unless I am mistaken?

    Obviously this image isn't axis separated, but hopefully illustrates what I mean.
    (I am also aware that the etkc isn't a fastback, so would have different values, but its just an illustration)

    upload_2021-1-10_12-37-56.png
     
    #1 aljowen, Jan 10, 2021
    Last edited: Jan 10, 2021
  2. ltntai

    ltntai
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    Mar 18, 2017
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    365
    The blue lift lines appearing at the base of the windshield are from chassis and firewall. The windshield base generates some downforce as shown in 2nd image.
     
  3. aljowen

    aljowen
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    Ah, yes, you are correct. Maybe its just an error (or compromise) in the liftCoef values for that area then?

    But it still doesn't totally explain why areas like the top of the windshield are generating downforce when that should be lift.
     
    #3 aljowen, Jan 10, 2021
    Last edited: Jan 10, 2021
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