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Thread: Falling bombs slip in wind condition

  1. #1
    Ace Rostic's Avatar
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    Falling bombs slip in wind condition

    In Cliffs of Dover from 4.312(oldest version I tested) to 4.54 in wind condition falling bombs are additionnaly affected by wind, and it is wrong. Problem is visible at least for course that bombs falling.
    I was trying to find bugreport about this issue on bugtracker, but not found, so here will be topic.

    In addtition I had to say that I'm not sure that bombs speed has same problem, additional tests needed and will be done later, if I determine how to do that.
    How things should be (if I'm not wrong). When airplane fly to the North (course 0°) and wind is blowing from the west (from 270° to 90°), airplane will have side slip angle X° to the right in relation to the ground. So to fly with course 0° it must fly with heading (360-X)°. If some one drop one bomb (10000kg for example) the bomb will be falling with the same heading that plane fly, because they are in same air environment. In relation to the ground both of them will have same slip angle X° and their course will be 0°.

    How I found this issue.
    I had created mission where wind blowing from west (from 270° to 90°) with speed 15m/s, created a very long target oriented from south to the north and place an He111 on altitude 5000m.

    This is three way of how I got the slip angle.
    1) In the game I synchronized my bombsight vertical line with the ground objects that goes through this line from top to bottom and I got +9° airplane side slip angle.

    Near the target my plane was stabilized with indicated air speed (IAS) ~255km/h (±5kmh between 2 tests) on altitude 5070m (±50m between 2 tests) (target elevation is ~0m).
    2) Also I used my excel table to get the side slip angle. I got +9.3° for true air speed 331km/h. Here I must say that my excel table calculate TAS with error ±10kmh, but this give maximum error in ±1° to the side slip angle.
    shutrman-values.png
    3) In addtition I was using html page (little bit modified by me) that calculate plane heading in wind condition and it gave me heading 350.7° for course 0° that corresponds to side slip angle +9.3°
    wind computation.png Original tool is here: http://ded-squad.ru/ded/veter.html

    So what I got when bombs hit the ground? When slip angle set to bombsight (just before release) was 9°, bombs hit the ground much to the right from target. best run slip 9.mp4_snapshot_03.10.072.jpg


    When I repeat my test with same conditions with the double side slip angle 18°, bombs hit the target. best run slip 18.mp4_snapshot_01.57.040.jpg



    Mission and instruments in attached file:
    bombing-wind-issue-.zip


    P.S. If I'm right, then I'll create bug report on bugtracker later.
    Last edited by Rostic; Jan-20-2019 at 10:21.
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  3. #2
    Ace Rostic's Avatar
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    Re: Falling bombs slip in wind condition

    In addition I can say that this trick, with double multiplying of side slip, work for any wind speed and direction with any airplane speed and direction.
    For level bombing I fly only He111. Other bombers have to be tested....
    Last edited by Rostic; Jan-20-2019 at 14:08.
    PC spec: Intel Core i7 8700K 3.7Ghz, DDR4 32Gb 2666Mhz, Asus Prime Z370-A, ADATA XPG SX8200 240Gb (PCIe Gen3x4), RTX 2060 6Gb
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    Ace Rostic's Avatar
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    Re: Falling bombs slip in wind condition

    I had some discussion with JG4_Hanseat. He showed me and interesting video with one very interesting picture. And looks like I'm wrong in some aspects of falling bomb process.
    This shows some new problem with bombing.... but it is another story.

    1.PNG

    PC spec: Intel Core i7 8700K 3.7Ghz, DDR4 32Gb 2666Mhz, Asus Prime Z370-A, ADATA XPG SX8200 240Gb (PCIe Gen3x4), RTX 2060 6Gb
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    Re: Falling bombs slip in wind condition

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