Rib stitching vertical stabilizer

[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.

[astjp2]

He might be including the diagonal?

[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]

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

[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.

[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]

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.

[Bruce Caldwell]

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