Rib stitching vertical stabilizer

[Bruce Caldwell]

Can you guys tell me how much of the vertical stabilizer gets rib stitched on a 46 BC12D?
Thanks!!!

[3Dreaming]

Just the top 2 ribs get stitched. I have never seen any documentation on factory spacing, so according to AC43 you can use up to 5" spacing. You might want a little close on the lower rib, or it might balloon between the stitches.

[Robert Lees]

My 1946 BC12-D fin only has two longitudinal ribs, Tom...and only the upper one gets stitched. If you stitch the lower one, it looks as puckered as an old grandmother sucking a lemon.

[3Dreaming]

I looked at the 46 project we have here in the shop, and it has both stitched. The spacing is 1" , so it doesn't look all puckered up. We did not do it that way, it was all ready done when we acquired it.

[astjp2]

Prewar and post war I think were slightly different, and rob’s looks great. Mine has 2 ribs Stitched.

[Robert Lees]

Just the top 2 ribs get stitched. I have never seen any documentation on factory spacing, so according to AC43 you can use up to 5" spacing. You might want a little close on the lower rib, or it might balloon between the stitches.

3Dreaming suggests there are more than two ribs. I respectfully believe he is mistaken...has anyone seen three horizontal ribs in a 1946 BC12-D fin?

[astjp2]

He might be including the diagonal?

[3Dreaming]

The pre war airplanes with which I am most familiar have three ribs. https://www.alliancememory.org/digit...id/348/rec/431 It appears that the third rib was omitted on the post war airplanes. Whether it is two or three, it is still the top two.

[Robert Lees]

Vertical rib spacing is different, Tom, as are the overall dimensions between the pre-and post-war fins.

I'll bow out of this discussion now; good luck Bruce coming to your own conclusion.

[Scott]

Two ribs, stitch the top rib only was the conclusion I reached after researching. It also becomes clear when you see how far the fuselage top tubes pull the fabric away from the lower rib.

once you've shrunk the fabric, push it to the rib with your fingertips in the stitch locations. You'll see it takes alot of pressure, and the fabric takes an unsatisfying line.
There is a third option, which is to stitch to the rib (as opposed to stitching through the fabric on the other side) but don't pull the lacing tight. I'm not sure there much purpose to this and can end up looking odd.

When mine was covered in the sixties, only the top rib was stitched. This works, and the fin ends up with a nice natural shape.

I used 2.5 inch spacing only because I did all stitching at 2.5"

[Bruce Caldwell]

Looks like I'll just stitch the top horizontal rib at 2.5" I cant thank you guys enough. Don't know what I'd do with the forum.

[Mark Bowden]

This is what a two rib vertical will look like with the lower rib stitched. It was done in 1999 whether factory correct or not on Ceconite. It is a July built 1945 with the two vertical ribs in alignment with the two hinge rudder ribs. As Rob indicates and seeing Scott's at Oshkosh stitching the top only looks better.

[Mark Bowden]

There may be an in-between solution as well.
These photos are from 1963 in Irish Linen

It appears from the slides that the aft half of the lower vertical rib may have been stitched. There is stitch tape evident. However from the smooth curve of the paint stripe going up the vertical it appears to be way to smooth to have the front 1/2 half of the rib stitched as there are no puckers. Zoom in and you can see it.

Of course the answer with respect to the actual "need to" stitch could be quite different between the use of linen vs. polyester.

I would suggest that given Taylorcrafts efforts at removing rib stitching in the wings of the '46's that they looked at all areas to remove stitching like they removed the rib in the vertical. Less stitching = less cost in pre vs. post war. And better appearance.

[Bruce Caldwell]

Good call Mark, Thanks! I think I will just stitch the top rib. I really don't think the lower rib needs it and don't want the puckering that it would cause.

[Ragwing nut]

The bottom one wasn't stitched. They had a 3/8" metal strap that pk screwed at the front and wrapped around the vertical post with pk in it. Then it was taped over.