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Bolt edge distance in steel fittings.

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  • Bolt edge distance in steel fittings.

    Specifically the 1/4" hinge bolts in the .071 flap and aileron hinges. Apparently these holes were pre-drilled in later wing kits, mine aren't. Gives me a little more flexibility in alignment, but I wan't to make sure I maintain minimum edge distance. I'm thinking it is 1 1/2 x bolt diameter measured center of hole to edge. Have looked through AC43.13 and Tony Bingelis books without any luck.

  • #2
    Make sure you get the holes towards the edges of the brackets (commensurate with edge distance). Otherwise, you cannot get a socket on to tighten the bolts.

    Ask me how I know this .......


    • zkelley2
      zkelley2 commented
      Editing a comment
      Haha, yup. Two wrenches and 3 minutes each!

  • #3
    See Oct 2019 Sport Aviation pg 108 for some insight.
    Patrol #30


    • #4
      Thanks Gerry, that was timely.


      • #5
        I had some issues with edge distance with the hinges. Bob takes almost every fastener close to an edge right to the limit. I guess thats how to design and build a light airplane. In some places like the hinges, he cheats if the fastener isn't "loaded" in the direction of the edge. If I remember right, the AN3 bolts on the hinge brackets end up being too close to the edge. If you don't drill them that way, there isn't enough room to turn the head of the bolt. Ask me how I know.


        • #6
          OK, I now see what you mean about the AN3 bolts holding the hinges on the flap and aileron spars. Thanks for the heads up guys. That would have been another mistake. Have others found the flap and aileron installation a PITA?


          • #7
            Yes. I won't go into details. I take responsibility. I'm having a machinist remake some hinge angle right now for me. I recommend not doing this step until the wing is fully riveted closed so that the wing gives a stable platform to align the flight controls.

            Psychology of building airplanes confirms this conclusion i heard once upon a time. Avoid letting problems build up. When you come across a problem try to solve it right away rather than set it aside. If multiple problems get set aside, then the pile can seem insurmountable and suck the enthusiasm out of the project.
            Brooks Cone
            Southeast Michigan
            Patrol #303, Kit build


            • robcaldwell
              robcaldwell commented
              Editing a comment
              Totally agree. When I started my build, I committed to one task at a time until completion. I've deviated from that only a few times while waiting for parts to be delivered, researching, etc. But always went straight back to the item after getting what I needed.