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  • Tail Inspection Port Size

    I'm finishing up the inspection ports in the fuselage and scratching my head on the size and shape to make the access ports for the elevator control horns. It appears that most use a rectangular opening and some use a round opening. I'm ok with either shape, but wonder about the size to make it. Any feedback? Taller than wider? I'm thinking that makes more sense than wider than taller. Thanks!

  • #2
    Damn you are making fast progress if you are at the covering stages
    N678C
    https://eaabuilderslog.org/?blprojec...=7pfctcIVW&add
    Revo Sunglasses Ambassador
    https://www.youtube.com/channel/UCQ0...tBJLdV8HB_jSIA

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    • #3
      You get there faster than you'd think. I am trying to make sure that I have every little thing that has to be installed before covering. Servos, wiring from the tail forward, static ports installed, GPS and transponder antenna mounts installed (com antennas are going on the wing roots), additional fairleads (I don't like the control cables dragging on the floor), all of the inspection ports. Gotta think about where fabric is going to terminate and make sure you have any tabs installed that you need. And after all that, I'll miss something, probably more than only one thing! When I get into covering, I want to focus on that solely until it's done. I'm sure it won't turn out that way, but I'm a gonna try!

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      • #4
        Mine are 8" tall and 7" wide. I also have a standard round 3 1/2" port below to access the head of the tail stinger bolt. 4" circular covers for the front stabilizer connections. Used .032 aluminum for the frames at front and back of stab to secure the fabric.

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        • #5
          In re accessing the stinger bolt head, this must be a difference between the full size BH and the Companion because mine is outside the covering

          IMG_1272.jpg

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          • Mark Dickens
            Mark Dickens commented
            Editing a comment
            Nev, that's a great idea! Consider it copied!

          • Bcone1381
            Bcone1381 commented
            Editing a comment
            I'll do that too!! But when you put your ship away in the winter time cover that hole up with a piece of Gaffers Tape to keep the curious mouse out.

          • N942VT
            N942VT commented
            Editing a comment
            Be carful with an opening in the tail area, it can actually let exhaust fumes in. Many SuperCub guys have found that out and traced it down to the tail being open.

        • #6
          If the holes are too small, it's a fiddle to assemble the whole thing after you've covered. Particularly getting the elevator horns and trim horns through the holes and hinges aligned at the same time.
          Generous is better, you'll never regret it. Plus you need to access the area in inspect each year - you are wise to leave room to see all those cluster welds down by the stinger attachment tube.

          Ensure the edges are either welded into the steel parts or have good bracing to the steel tubes (adel clamps or whatever), else the fabric will vibrate free from the inspection plate after a while and end up slightly slack.

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          • Mark Dickens
            Mark Dickens commented
            Editing a comment
            Assembly after cover has been one of my biggest worries. I could just imagine getting to that point and not being able to put it together...nightmare

        • #7
          FWIW I have 5 kit log entries on this.

          homebuilt aircraft, builders log, experimental, experimental aircraft, 51% rule, fifty-one percent rule, 51% percent rule, aircraft homebuilt kit, aircraft homebuilt plan, aircraft composite homebuilt, aircraft experimental homebuilt, aircraft experimental kit

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          • Mark Dickens
            Mark Dickens commented
            Editing a comment
            I've bookmarked your site...good stuff there!

        • #8
          Every one I do the inspection ports get bigger. This one is 9x9 on the inside, the covers are 11x11. You need to get both hands in there to hook things up, especially if you have turnbuckles to safety wire. It's not just the size but the placement so I would mount the stab and elevator on one side and it will become clear where you want them. Make the upper half of the cover extend long enough to capture the lower half and the break will be hidden behind the fairing. I also have a round ring below the forward. stab area. Pic 161.jpg

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          • Mark Dickens
            Mark Dickens commented
            Editing a comment
            Awesome! thanks...I was thinking that 6x6 might be big enough but I'm going to biggie size it now, and definitely mount the stab and elevator for placement

        • #9
          Originally posted by Battson View Post
          Ensure the edges are either welded into the steel parts or have good bracing to the steel tubes (adel clamps or whatever), else the fabric will vibrate free from the inspection plate after a while and end up slightly slack.
          Battson,

          I plan to install the inspection frames in accordance with the Stewarts Fuselage Covering Video at 26min 25 seconds.
          Official Piper Fuselage Covering instructional video from Stewart Systems. See directory below to jump to any part of the demonstration.Introduction https://...

          Also this at 1hr, 25min, 00sec. https://www.youtube.com/watch?v=MGpMEuPnM7g&t=1490s

          This method encapsulates/sandwiches the frame with fabric. Did you encapsulate your frames with fabric? Do you believe the the bracing you describe is still prudent?
          Last edited by Bcone1381; 09-30-2021, 07:43 AM.
          Brooks Cone
          Southeast Michigan
          Patrol #303, Kit build

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          • #10
            Originally posted by Bcone1381 View Post

            Battson,

            I plan to install the inspection frames in accordance with the Stewarts Fuselage Covering Video at 26min 25 seconds.
            Official Piper Fuselage Covering instructional video from Stewart Systems. See directory below to jump to any part of the demonstration.Introduction https://...

            Also this at 1hr, 25min, 00sec. https://www.youtube.com/watch?v=MGpMEuPnM7g&t=1490s

            This method encapsulates/sandwiches the frame with fabric. Did you encapsulate your frames with fabric? Do you believe the the bracing you describe is still prudent?
            I didn't fully encapsulate the frames, I treated them more like a termination to a tube, which was probably a mistake in hindsight.

            I would suggest that a full encapsulated one will last a lot longer, but not indefinitely. Inspection rings like that are not designed to have a dozen screws installed and removed at least once a year, they also transfer the loads from the cover plate directly to the ring, the fabric does little to resist movement.

            The ones which are fixed into the stringers or fuselage tubes worked really well, they haven't come loose generally speaking. The ones which are like a window through the fabric, which float and vibrate with the prop wash did not work well. All the seams came undone. The fabric generally stays put, it's not a major issue requiring repair - but it is annoying. In one place I got a wrinkle when the fabric came free.

            The metal rings needs to be scuffed up really rough to ensure a good glue bond, otherwise I can work loose in a matter of a few dozen hours.

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            • #11
              I've done lots of them with the sandwiched Stewarts method and had no problems. The frames are one piece .040 and roughed up real good. The fabric is glued inside and out and will not pull away, at least with Stewarts. Undetermined with other systems.

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              • Battson
                Battson commented
                Editing a comment
                How many hours have they sat behind the 260hp engine?

            • #12
              300 HP Lycoming and big Ham Std prop in a stearman hasn’t bothered them. Jacobs powered Waco too. Are you saying it won’t work with a 260 hp Bearhawk? That would surprise me.

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              • Battson
                Battson commented
                Editing a comment
                That's not what I said at all. I asked how many hours they've been in service with the large engine battering them. Mine were probably fine for the first 500hrs or so, I can't recall exactly when they let go.
                P.S. I have some tiny little encapsulated rings under the stabiliser, and working on the plane yesterday I just found those had also let go too. So go figure.

            • #13
              Originally posted by N942VT View Post
              There is a lot of fuselage tube structure above the stab attach point, as pictured here.

              Longeron, bracing tube, etc. That makes reaching things from the top more difficult. The best access is from underneath, it's unimpeded. If you had to disconnect and reconnect a cable without adjusting the turnbuckles, for instance to remove an elevator for repair, underneath is the best place to do it.

              Make sure you leave enough room to install the elevator horns, which need to come in from the bottom and then be rotated up and into place. The picture above, I would say that's the minimum amount of room below.

              The other thing to remember, once the rudder is installed you cannot reach around the back of the tail post to tighten and loosen bolts. You have to remove the flying wires to remove the rudder. This is annoying. Ideally, leave enough room to reach both sides of the elevator horns / trim horns, both top and bottom. At the top, because of the longerons obstructing, you need more room.

              Here's what I have, this is large enough below the longeron but a little too tight above:
              IMG_20211003_094805.jpg
              Last edited by Battson; 10-04-2021, 05:52 PM.

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              • #14
                On the left side,the bolts were passed through small holes and used a couple dollar fabric patches- the regular access ring is to connect trim cables - I have large cover on right side
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                • #15
                  I must still do the one in the back where everything comes together, but I added this one to be able to have an extra opening to get another hand or an extra set of hands in to help
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