Plastic sheet/strip

Big Ed

N50247 - '79 Super D
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Jul 20, 2020
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Tampa, FL
I've got a couple of spots where cables and control hardware are cutting thru the belly fabric from the inside. I'd like to cement a strip of thin plastic or poly to the inside of the fabric as a sacrificial surface at hotspots.

What kind of plastic are inspection rings made of? Is that material available in sheet form? Is there another suitable material that might be commonly available?
PXL_20210628_183355067.jpg
 

Big Ed

N50247 - '79 Super D
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Jul 20, 2020
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731
Location
Tampa, FL
Looks like inspection rings are typically made of cellulose acetate butyrate (CAB). ACS has sheets but they are large and expensive. Looking for other sources.
 

kubark42

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Mar 25, 2021
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Massachusetts
Delrin is a great low-friction, high-wear plastic. Any kind of HDPE is also good and low-friction. Neither of them glue very well, though.

You could also build a chafe guard by simply doubling up with some extra dacron. My understanding is that the goal is not to prevent wear so much as to slow wear down to the point that the chafe protection outlives the fabric elsewhere. At this point, anything light will do. Heck, you might even try a small scrap of formica, as the paper-based backside allows it to be glued and the kitchen-facing front-side is very, very high wearing.
 

Big Ed

N50247 - '79 Super D
Joined
Jul 20, 2020
Messages
731
Location
Tampa, FL
You could also build a chafe guard by simply doubling up with some extra dacron.
That is what I did as an interim measure over the weekend. Glued a double strip of Ceconite 101 heavy duty fabric to the backside. That should last at least a few months while I look for something better. After researching, I think CAB is probably the right material. Just need to find a decent source for small quantities. Maybe at Oshkosh?

At some point in the past, someone glued glass cloth to the inside for the same purpose. Not sure how long ago, but it was cut completely through on the rear area. Proper tensioning of the cables should help, BUT ... when I pulled the cables tight, it did not raise them up off the fabric. Am quite certain that pulling G's is going to press the cables hard against the fabric.

PXL_20210628_003611668.jpg

PXL_20210628_003611668 (1).jpg

The worst spot is directly under the torque tube casting. That makes direct contact with the fabric and cuts into it every time the torque tube is rolled.

torque tube casting.PNG
 

Hiperbiper

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May 30, 2020
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Shreveport Louisiana DTN
Ed,
When tensioned properly the cables (if they are routed correctly) shouldn't ever come into contact with or abraid the belly fabric. At least I've never seen it. And I'd like to think as long as this airframe has been in production something like this would have been identified and fixed...
Chris
 

Big Ed

N50247 - '79 Super D
Joined
Jul 20, 2020
Messages
731
Location
Tampa, FL
Ed,
When tensioned properly the cables (if they are routed correctly) shouldn't ever come into contact with or abraid the belly fabric. At least I've never seen it. And I'd like to think as long as this airframe has been in production something like this would have been identified and fixed...
Chris
The cables are properly tensioned and routed. We checked both today.

Possibly the belly stringers are bowed in a bit between the tabs. It doesn't look that way, but I did not put a straight edge to it to check. Wouldn't be able to do much about it.
 

Joe

Member
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Jul 10, 2021
Messages
15
Location
Fabens, TX
Best solution cure what ever is causing them to touch the fabric. Plan B glue down a strip of leather, if you can get a good bond to the fabric.
 

Bob Turner

Well-known member
Joined
Apr 4, 2018
Messages
1,537
Actually, I think the plastic is a good idea. Try a model train shop. It comes in sheets. And Super Seam will probably hold it forever.
Agree, though - better to build up the stringers so the fabric clears.