general forum thoughts on the Belite part 103??

Discussion in 'Hangar Flying' started by revkev6, Feb 10, 2015.

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  1. Apr 18, 2016 #61

    choppergirl

    choppergirl

    choppergirl

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    Maybe wrap it all the way around pipe instead, then sandwich it together and rivet or bolt *that* together.

    Something along the line of these? Metal wraps around pipe, then is bolted together along with your strut or whatever.

    [​IMG]

    http://c1552172.r72.cf0.rackcdn.com/2469_x800.jpg

    http://c1552172.r72.cf0.rackcdn.com/287267_x800.jpg

    http://c1552172.r72.cf0.rackcdn.com/287266_x800.jpg

    I'd use something several inches long (as opposed to 1 inch like in picture). Put a bolt through in least critical load direction to keep it from sliding along pipe or twisting.

    Look how its done on my plane:

    http://dcim5.peachcountry.com/DSC_9936.JPG

    http://dcim5.peachcountry.com/DSC_9935.JPG

    http://dcim5.peachcountry.com/DSC_9937.JPG

    Look where they attach struts to fuselage, same idea... squash main strut ends flat, wrap around a metal sandwich, slide strut tube in, drill hole and put bolt through:

    http://dcim5.peachcountry.com/DSC_9932.JPG

    Doesn't inspire much confidence, considering the entire 575 lb weight of my ultralight+pilot is supported by these four main struts and these four little bolts, and that that increase by a factor of X with G loads in turn/climb/dive. I guess it worked as long as you don't do aerobatics...
     
    Last edited: Apr 18, 2016
  2. Apr 18, 2016 #62

    PTAirco

    PTAirco

    PTAirco

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    And they bring at least one line of rivets up high enough to be on the neutral axis where they are actually in pure shear. None of these are anywhere near in pure shear.
     
  3. Apr 18, 2016 #63

    BBerson

    BBerson

    BBerson

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    image.jpg
    True, the Avid has more rivets below the neutral axis. Also bonded.
    Looks like 1/8" steel rivets. 5 rivets on bottom in almost pure tension (not visible in photo)
    What is the shear and tensile strength of each rivet?
    Most are loaded both in shear and tension together. Could a rivet take more load in shear and tension together?
    Edit:
    I found my box of Fastenal 5/32" steel rivets. It lists 420 shear and 600 tension.
    This info was hand noted on box by me. Not sure if I got the info from the store or website.

    Hollow tubular pop rivets are apparently stronger in tension.
    Solid rivets are stronger in shear.
     
    Last edited: Apr 19, 2016
  4. Apr 20, 2016 #64

    pylon500

    pylon500

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    While the strength of the rivets can be added up to do the job, the weak point is actually the 'stress raiser' holes in the structurally 'bending' tube as a primary structure.
     
  5. Apr 20, 2016 #65

    Matt G.

    Matt G.

    Matt G.

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    Is that your opinion, or have you done some analysis of the joint to determine the critical failure mode?
     

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