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Wing Rib Stitching - placement of first stitch and spacing

Sam D

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Petaluma, CA
This question probably falls under thinking-way-too-much-about-something but here goes. I'm finishing up some tasks with the wing before covering and trying to figure out placement of the first stitch and can't quite figure out how I'm going to stay away from the aileron cable.

According to 43-13, the first lace on a wing rib should be spaced from the leading edge fairing no more than 1/2 the required lace spacing for the balance of the rib. This is probably the basis for "start 1" back" I see periodically referred to.

My problem is the aileron cable. In the inboard section of the wing, its about 1" back of the leading edge. It then hits a pulley and is then about 1.5" back of the leading edge. Here are some poor pictures:

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Question 1: First stitch Where do folks place this first stitch? It looks like 1.75" would work out (with 3.5" spacing noted below)
Question 2: Spacing Do you follow the Piper plans (3" spacing) or 43-13 (3.5" spacing) outside the prop arc?


Thanks,
Sam
 

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I do 2.5 for the entire wing. Keeps everything lined up and symmetrical. It’s only like 3 extra stitches per rib. No big deal. Also use a laser level light for your layout. Way less messy than a chalk line. I start the first one at 1.25 from the pic.
 
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I am lazy, I did 2.5" for the whole wing, it was just easier to figure out for me.
 
You can use Piper spacing if you can find out what it is. Whatever you do, check out the Stits lady, and her "palm tree and rabbit" technique - way easier and better looking than the traditional way.
 
Bob - Got anything more specific? I googled stits lady palm and rabbit and I’m pretty sure what came up in my search results was not what you intended!
 
Yes, that's the one. I have been rib stitching for a half-century, and that was "life-changing!"

Assuming the OP is doing a Super Cub, surely there is a factory drawing of stitch spacing? Maybe Clyde knows?
 
I teach the 1/2 starting distance. However, in the case of the picture, you don't want the lacing around the cable inside the wing. You can do a single locking stitch just before the cable than a new starter stitch just after the cable if you like. I look at the layout of the stitches than get out my rivet fan to help get the layout looking good. I will adjust so the first and last stitch are the same distance from the ends of the rib. As long as you have the minimum required, you are good to go. I always end up with closer spacing because it looks better to me. With the stitching closer in the prop wash area, adjustment is often needed to get all the stitches nicely lined up.
Marty57
 
Thanks Marty. Good idea with the rivet fan. That probably helps when adjusting for the difference in length between the top of the rib and the bottom.
 
I start out on the bottom of the wing, and lay out my spacing.then get a piece of 1/2 wide elastic and lay it down adjacent to the rib pulled tight, but not stretched. I mark where the leading edge ends, and the trailing edge is, then where each hole goes, all on the elastic. Flip the wing, and align the leading edge mark, and clamp or tape it so it can’t move. Then stretch the elastic so the trailing edge mark lines up with the trailing edge. Now you have all your hole locations layer out and perfectly spaced to lineup with the holes on the bottom.

For needles, I just take pieces of welding rod long enough to go through the wing. Grind a point on one end, and flatten the other end and drill a hole that you can pass your chord through. I make anywhere between 6 or 10 needles, stand the wing on the leading edge and work multiple ribs at the same time. Pass the needles through one side, walk around to the other and make all the knots, then pass back to the first side - repeat. On a 13 rib wing, with a fuel bay, and enough needles, you can get the wing finished in one sitting. The hardest part is not tangling the chord.


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Me too on the needles - mine are coathangers. I do the wing horizontal, and can still look through an adjacent hole to see where to put the needle, so I just do one rib at a time. Takes about six hours per wing, but now I space it out over two or three days. I have about four hours of useful work per day left in my body. I have covered a Cub wing through tapes in two days flat (when I was younger).
 
Me too on the needles - mine are coathangers. I do the wing horizontal, and can still look through an adjacent hole to see where to put the needle, so I just do one rib at a time. Takes about six hours per wing, but now I space it out over two or three days. I have about four hours of useful work per day left in my body. I have covered a Cub wing through tapes in two days flat (when I was younger).
I do mine that way too, Bob. I use a rotator and 4 needles. Wing stood on edge and walk around. Lay a bunch of thread and then right and tie off. Works well for me. If I have help on the other side of the wing it is a pretty fast method.
 
You want fast stitching ..... train the grand kids! They were not content with just passing the needles through; they wanted to do the entire stitch themselves. Not only can they see the holes; they can bounce from top to bottom without the loud POP coming from my old bones!

Marty 57

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Are those your wings Marty?
No, those are the Waco wings I just finished. Mine are on the wing rotors waiting to be covered. My grandkids will be doing a lot of the covering on my wings. They are really excited about doing the covering. The girls are 11 and 15.
Marty57

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You want fast stitching ..... train the grand kids! They were not content with just passing the needles through; they wanted to do the entire stitch themselves. Not only can they see the holes; they can bounce from top to bottom without the loud POP coming from my old bones! ....

The Port Townsend Aero Museum (on my home airport) has a youth mentorship program,
the kids in the program do a lot of rib stitching.
In fact, one particular 16 year old girl is the probably best stitcher there.
I forwarded this video to their shop foreman,
turns out it's the same one he has all the kids watch when they're first learning.
In case anyone is interested, here's their website:

Port Townsend Aero Museum | Aviation History | Aircraft Restoration (ptaeromuseum.com)
Youth Program - Port Townsend Aero Museum (ptaeromuseum.com)
 
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