Finishing Fabric Around Gear Attachments

Mark Dickens

Mark Dickens

Companion QB
I'm "this close" to finishing off covering the fuselage but I'm stumped on the best way to attach the fabric to the gear/wing strut attachment. I have the belly fabric attached to this area after a fashion but I'm not happy with it. Anyone have some pointers or photos to share on this?
 
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Those are tough locations which is one of the reasons, though minor, I chose to go with metal below my doors.

I’ll see if I can find some pictures of my airplane even though they would be an example of what not to do.
 
I used polyfiber polytak which bonds to mylar and polycarbonate sheet. If Ekobond works to bond, you can make odd shapes and reinforcements and glue to fabric and then glue fabric over them to finish.
 
That area flexes a lot if you have a hard landing (I mean hard) so you need a good bond. It is possible for fabric to come free when that kind of event occurs, if the fabric has less than a complete wrap-around where the fabric terminates onto the tube structure, per manufacturer's instructions.

Some of my fabric in that area came loose after we "rolled over" an considerable obstacle on the ground which caused the tube structure to flex by around 10mm (3/8"), and the fabric needed to be re-shrunk to remove creases and prevent loose fabric from drumming. We also added more Polytak and remade the bond to the tube structure. To be clear - the tube structure all sprung back to it's original position, but it was enough to affect the fabric.

For this reason, I am also in favour of metal around the legs and below the doors. I am sure fabric is equally useful, provided it can be attached in a strong fashion.
 
I am going with all metal under my doors all the way to the aft door former, so it's the aft attachments that bother me. See below, it's obvious why they bother me.

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That hole is what concerns me, not necessarily because I think it will come off since it's reinforced with heavy fabric and it's not in the direct air stream, but because I just don't like openings. Jim's idea of using polycarbonate has given me an idea of perhaps using some Kydex that I have for reinforcement, assuming that Ekobond works with Kydex. But no matter what I use the edge that abuts the gear attachment just hangs out there. I suppose if I was going to redo the whole area, I could have welded a small piece of sheet to the frame to provide a support, but my motivation for starting over in that area is very low.
 
The more I think about this, I think I'm just going to cut off that area, tack weld a small tab in that corner and use that to attach the fabric. I'll post a photo when I'm done
 
Mark this won't address your question, but to show another way to tackle the whole area. I used Whee's method with sheet metal around that area, which allowed me to terminate the fabric on the door rear pillar. So far it seems to be working quite well.

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I too have gone with all metal under the doors (I'm a RV builder after all) all the way to the aft door former. It's not the side pieces where I'm focused, it's the belly where the fabric meets the aft gear attachment. I've now fashioned some aluminum reinforcement plates which I've bonded to the fabric and will reinforce on both sides with heavy fabric. I realized that I'm probably overdoing my concern here. With side pieces mounted and the boot cowl extension in place, it will all be fine. One of my concerns is trying to seal up as many holes that would let carbon monoxide in, but I think that's largely futile. These planes are as well sealed as a screen door in the best case.
 
I can see that I've misunderstood but looks like you're on the right track. Yep the screen door analogy is apt. In the end I simply angled my exhausts lower and haven't had any CO issues since.
 
I followed Paul's example and am real happy with how it turned out. Paul alodined his. I used self etch primer after scuffing with 320 grit abrasive. EkoBond needs a roughened surface to bite into for its mechanical bond. Every inside corner or unsupported area on my covering job has a gusset like Paul's, like the rudder horn. I used a 1 inch overlap fabric patch over the gusset.

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I ended up sandwiching an aluminum plate between the belly fabric and a heavy fabric doily. It ain't pretty but I'm happy with it

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I used metal under the doors, but used a single layer of 6 oz kevlar (pre-laminated flat) around float fittings which are similar. Under the fabric instead of sandwhiched between. Fiberglass would be just as good. My float fitting fabric (Oratex) looks just like the above pics.
 
Yesterday, I met a nice chap, Ernie, at Koritz Field Rochelle, IL who was about to go on his light-sport check-ride in his fabric wing, weight shift trike. In looking at his machine I noted neoprene wraps around several attach points at strut-to-fuselage. Now, these looked like bottomless beer coozies to me, and may very well have been, but they did a decent job of fairing a difficult junction and looked good. Neoprene is cheap, available in every color, easy to sew/glue or attach to itself with velcro, and could be cut away if they are no longer wanted. Maybe this is not the most aeronautical of solutions, but it’s an idea.

On cabin CO: A good quality, electronic CO detector in the cabin and configuring the cabin to give a (measurable) positive, fresh-air pressure in the cabin would be how I might mitigate the poisoning risk.
 
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