Rear edge stiffeners ?

[Kitfox Pilot]

Did most you add these 3/8 pipes to the trailing edges ? I read they keep the rear edge from deforming when covering? Is this a problem when covering? I just read this on another build and had not heard of it.

[Shadowrider]

What type of covering are you doing? Not needed with Oratex but recommended with poly.

[efwd]

I used them. I used Oratex. The last thing I wanted to see was a trailing edge resembling the Batman logo.

[efwd]

The material is not included in the kit. It is not required and is merely a suggested technique many builders use to ensure the fabric doesn't warp the trailing edge.

[Shadowrider]

Was not included and no mention in our manual. Maybe the STI wing is different.🤷*♂️

[109JB]

They weren't installed on the Kitfox IV I am working on that was covered with polyfiber, and they weren't installed on my friends Kitfox IV also covered with polyfiber. Here are a couple pictures of the wings on my project airplane that have since had the covering removed. Trailing edge looks pretty darn straight to me. I'm sticking with the motto that everything you add adds to the empty weight. When I recover my IV it will not be getting any of these tubes.

20200401_164951.jpg

Flaperon close up.jpg

[bbs428]

Someone else came up with this idea. I just plagiarized and tweaked it.
I priced out some carbon tube. Was more economical to buy these practice carbon arrows and you can get two braces per arrow. I will be
covering the wing soon so I'll let you know how it goes. Lighter than the aluminum tubes? Yes. Stronger? Yes, since it is in compression.

[jrevens]

Mine might have been a little different than Delta Whisky, but I originally thought the tubing wouldn’t fit properly also. However, I found that with the proper “rolling” technique it would pop into place nice and tightly, although I still used Hysol to really secure it.

[jrevens]

I used them with Oratex too, Harlan. As an aside, the first time I was folding my wings in the 3-point attitude (before the first flight) I stupidly let a wing rotate back & slam into a cabinet with the trailing edge. The result was a relatively minor repair. I believe that if I hadn’t had the stiffening tubes I would’ve probably had to replace a section of the trailing edge.

[jiott]

In my opinion the stiffeners are a must; the 350F final fabric shrink pulls on that edge with a LOT of force. Some folks, I have heard, stop at 250F or so, but I have seen several in-flight videos of the top surface of the wing bulging up; so I personally want maximum fabric shrink and tightness on the wings. Even with the stiffeners I put a straight edge on the trailing edges after 350F shrink (I used Polyfiber) and found them slightly bowed inward about 1/8" at midspan, which was not visually noticeable.