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Thread: 4130 fuselage truss

  1. #1

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    4130 fuselage truss

    Hello,


    I'm quite a beginner in 4130 fuselage truss conception and I'd like
    to have your opinion about an example.


    Is longeron continuity at the tail cone mandatory ?
    Is it possible that a cabane be welded to the fuselage tailcone and
    not having longeron continuity at all but weldments (as shown in
    the drawing below at B and C) ?


    Another question is the weldment of longeron with a different
    6°angle tube (at A) and I'm asking myself if is it possible or not
    (from a strenght point of view).


    Last question. Have you a book proposal about 4130 fuselage truss
    conception and welding ?


    Thanks for sharing your thoughts.
    Attached Images Attached Images   

  2. #2
    planecrazzzy's Avatar
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    I have a Fuselage log ...Maybe there's something you could use ?

    http://www.wingsforum.com/viewtopic....a1f32a0dfeb32d
    .




  3. #3

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    For sure, thanks for the information. I'm a great fan of wittman designs.

  4. #4
    Dana's Avatar
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    JLS, it can be done (breaks in the longerons) but it's not optimum. You will have to analyze each element (like you would for any truss anyway), and you'll probably need doublers or finger plates at those joints. At point C, you'll definitely need the green member, or some other substantial reinforcement.

  5. #5

  6. #6

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    I couldn't imagine anything better than this book for my issue. Thank you for your help.

    A more convenient drawing of the cluster A is below. It seems that upper longeron should be bent and not
    split at that place.
    Attached Images Attached Images  
    Last edited by JLS; 12-30-2020 at 09:57 AM.

  7. #7
    planecrazzzy's Avatar
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    This program for coping the tubes , has been handy.... you type in the size's of the tubes...

    and copy the pattern.... cut it out and wrap it around the tube after you cut it to length....

    http://www.metalgeek.com/static/cope.pcgi

  8. #8

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    Thank you. I saw your logs of the Buttercup project on wingsforum, and its quality is impressive.
    Last edited by JLS; 12-30-2020 at 09:57 AM.

  9. #9
    planecrazzzy's Avatar
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    Just like your print sample...
    I bent my Longerons where I could , it's just stronger than separate tubes welded.
    I have the proper tube bender dies...
    .
    Gotta Fly...





  10. #10

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    Thank you for your post Mike.

    Did you follow Earl Luce advices on cutting 4130 tube (videos
    on eaa.org) or did you produce your own methods (notcher
    lathe or others) ?

    No answer from Mike, never mind. "Design of light aircraft" from Richard Hiscocks can
    be an entry to design tail and have loads on it. I worked chapter 5 on flight envelope
    quite hard until I made a spreadsheet (GoogleSheet)...
    (continued on another thread 'Hiscocks Chapter 5')
    Last edited by JLS; 01-10-2021 at 09:16 AM.

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