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Aileron pocket close out.

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  • Aileron pocket close out.

    In an effort to keep the trailing edge of the wing skin as straight as possible along the top of the wing I used an iron bar and back-riveted the pocket covers to the top trailing edge of the wing skin against the bar, which turned out nice. I intended to do the same along the bottom of the wing and I drilled all the rivet holes in the skin and pocket covers.

    However, it seems I made a rookie mistake in doing so because now I cannot fully access the rivet holes with a squeezer or even with my bucking bar. This is because the angle is acute between the pocket and the bottom wing skin I see two solutions available to me:

    1. Use NAS1097 ”skin” or “oops” rivets countersunk into the skin which will avoid the need to get a squeezer in to dimple. Then get a short bucking bar with a 30 degree angle on the end which will tuck fully into the pocket and hopefully allow me to buck the rivets

    2. Use 3/32 pop rivets, which will be easy but will leave a row of little bumps in front of the aileron on the bottom of the wing. I also have ccc-32 flush pop rivets, but since I can’t get a squeezer in to dimple, I don’t think they would work.

    Since I have to finish this and I still have one more wing to go, I’m wondering how others worked around this issue? I made matters worse by not drilling and dimpling before assembly (in afford to keep things straight) and by placing my rivets almost 3/8” back from the edge to allow for trimming later if desired.
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  • #2
    I am having a little difficulty understanding the exact issue you're describing. But since I am very close to performing this task myself, I will be watching this thread closely.
    Rob Caldwell
    Davidson, North Carolina
    EAA Chapter 309
    BH Model B Quick Build Kit Serial # 11B-24B / 25B
    Build Log: https://bearhawk4place.blogspot.com/
    YouTube Channel: http://bearhawklife.video

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    • #3
      Same. I'll be at the same point very soon so I'll be watching. I'll let you know if I figure it out when I get there.

      Comment


      • #4
        I think the problem is interference between the pocket skin and the rivet squeezer which prevents the dimple die from being positioned in the hole.

        Tool Modification is a necessary task in building. I have modified my rivet squeezer, a few dies and bucking bars using a grinding wheel so that they will fit in snug places. This is one place that I may have done so in order to get the dimple die in position. I used regular AN426AD3 rivets. I think the head of the NAS1097 rivet would compromise strength in tension.

        You may consider removing the skin you installed. I've gotten real good at drilling out rivets. I think I recall having to drill my pocket skin out once.



        Screen Shot 2020-09-25 at 1.10.53 PM.png
        Last edited by Bcone1381; 09-25-2020, 01:25 PM. Reason: spelling
        Brooks Cone
        Southeast Michigan
        Patrol #303, Kit build

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        • Pbruce
          Pbruce commented
          Editing a comment
          Yes, Brooks has displayed the issue exactly. I considered the potential of compromised strength using NAS1097 rivets, but I don’t believe it’s actually much of an issue in this case: there is already a line of AN426 rivets a little more than an inch ahead of these ones for structural purposes. The forward line is dimpled and flush riveted solidly onto the spar ahead of the aileron. I’m quite happy with attaching the skin to the pocket covers with NAS1097 rivets. All they do is hold the pocket covers to the bottom skin. I have zero doubt that the plane would fly fine forever without them. I’m not recommending this; it’s just how I dealt with my mistake, and I’m comfortable with it. If the wings fall off, though, I will be the first to let everyone know 😜

          For anyone who is following behind and considering this issue, I would suggest trial-fitting the pocket covers first (like we always do, right?) Mine were a little undersized in some places which made bridging the gap between the top and bottom wing skins a little bit of a stretch). I would cleco the pocket covers to the little ribs, then drill the holes in the skins, disassemble, dimple and then permanently rivet with AN 426AD3 rivets. I would INSURE that the rivets are placed at the minimum distance from the trailing edge of the skin. I was ultimately able to push the squeezer set in just enough to squeeze the rivets, and as I said, I set mine away from the edge 1/8” too far. So if you don’t do that, you should be ok.

          You could also rivet the pocket covers onto the bottom skins first, but I would be a little worried about them pulling the top skin out of alignment, since its a bit floppier by virtue of hanging out a lot farther than the bottom. It’s also more important cosmetically for it not to be wavy.

          By the way, Mark G told me to back-rivet the trailing edge skins against an iron bar with my squeezer. I didn’t know you could do that with a squeezer, but it works good. This keeps the skins looking pretty straight in front of the ailerons and flaps.

          Thanks all.

      • #5
        To make a dimple in some inaccessible places there is a pop rivet dimpler. That might help where you can't make dimples now. Mark

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        • Pbruce
          Pbruce commented
          Editing a comment
          I didn’t know that. Thanks.

        • robcaldwell
          robcaldwell commented
          Editing a comment
          In think this is what Mark is referring to. https://aircraft-tool.com/shop/detai...d=5102D-3%2F32

        • Pbruce
          Pbruce commented
          Editing a comment
          Well, isn’t that coo! That could be a life-saver. By the way, I had to move the hinge brackets out of the way, and some fuel tank strap mounting bolts to allow access to the shop head of some rivets holding the bottom wing skin perimeter. Next time I’m just going to use a ccc-32 (flush) rivet instead on the skin instead of moving the hinge brackets. This occurs in two places, I think.

      • #6
        I dimpled my pocket skin before installing with a squeezer. Then I used an angled bucking bar which just barely had enough clearance to buck the rivets. I put a little tape on the corners of the bucking bar to keep from scratching the primer. Like Brooks I have a few dimple dies that I have ground the edges off for tight spaces. A modified pop dimple die should fit in that spot. Although my pop dimple die doesn't produce as good a dimple as the squeezer, especially with multiple sheets.

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        • #7
          A no hole yoke with some grinding might work here. The Yardstore sells one version

          https://www.yardstore.com/no-hole-yoke-pneumatic
          Scott Ahrens
          Bearhawk Patrol Plans Built
          #254

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          • #8
            That no hole yoke would make it easy. I have a squeezer set which is ground off for working around nutplates, but it was the corner of the yoke which interfered the most. That’s a really great looking tool!

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            • #9
              Zenair sells a pop rivet dimple die set. Very handy for blind locations.
              Last edited by spinningwrench; 09-26-2020, 10:27 AM.

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