Vertical fin fabric fairing

[Carrieve]

Hi gang, I am covering my Tcraft and don't remember how I faired the fabric from the vertical fin to the fuselage. Any ideas or pics would help.

[Scott]

There is curved tube that attaches to the bottom of the leading edge and extends down between the fuselage top stringers.

There's no suitable structure so the fuselage and fin fabric needs to be stitched using a 3/16" spaced baseball stitch, then covered with a 3" tape.

The above is in accordance with the polyfiber Stc. I imagine others are similar.

https://4.bp.blogspot.com/-e9Qh4VcLO...0/DSCN3966.JPG

https://2.bp.blogspot.com/-Y5lYDUQGL...N3976%2B50.JPG

https://3.bp.blogspot.com/-XU-c6MYiqW8/Vn27cWpxVOI/AAAAAAAACEo/BRqhPZ8LlOk/s1600/DSCN3965.JPG

https://4.bp.blogspot.com/-3Qhe4odWM6U/Vn9bE0joptI/AAAAAAAACKs/E7qsDPBUxtU/s1600/DSCN4106.JPG

more details here:

https://c-fclr.blogspot.com/p/blog-page_98.html?m=1

[Carrieve]

I recovered my girl 30 plus years ago and I could not remember. I don't think I used a tube and there was not one when I took it down. Thinkinh that might be a good idea. Was it 4130 tubing that went to the rudder leading edge?

[Hank Jarrett]

There is a small formed sheet metal piece that goes between the fuselage top and the leading edge of the fin called a Dahlstrom. It is missing on lots of planes and without it the fabric doesn't form that nice smooth curve between the fuselage and fin. I have one for my 45 that is off the plane right now and am not sure how hard it would be to make a firm to make them. Do enough people need one to make it worth making a tool? Anyone else missing theirs or have an extra one?

Hank

[Hank Jarrett]

Went back and did a little digging in my papers and Dahlstrom is actually the name of a custom metal rolling and forming company. I didn't see our part as something they normally supply so it could be that Taylor had them make a bunch of them a long time ago. I would imagine if you ordered a thousand or so if them at once they would be pretty cheap. Having them make ONE would be pretty expensive. If they aren't a stock item I am betting it would be orders of magnitude less expensive to make one.

Hank

[Robert Lees]

The "tubing" between the fin leading edge and the fuselage is called Dahlstrom C-section (I believe) [3.5 Mb pdf file]. It is reverse-curved to form the profile between the fin and a diagonal tube between the two top stringers, as seen in this photo. [Edit: crossed with Hank's posts]



In the UK we operate our Taylorcraft non-certified, so unlike Scott, I chose to glue the fin fabric to the upper fuselage fabric, rather than use a baseball stitch. This particular method was approved by the UK CAA for certified Austers, so that was good enough for me, and after 15 years there has been no signs of distress at this join.

Full description, including photos of my process, are here

Hope that helps, but as ever, get approval from your IA.

Don't rib-stitch the lowest rib on the fin!

[Scott]

I used a short piece of aluminium tubing that fit over the fin leading edge. Filled it with sand and bent it to shape. I think it was 6061 0 but any relatively soft tube will do.

I knew I must have a pic somewhere
https://2.bp.blogspot.com/-8H3EoJ4cR...0/DSCN3625.JPG

Oh and its actually 6061T6, so as usual I made it more difficult for myself!

[N96337]

Stewart Systems is the only system out there, that I'm aware of, that you don't need to stitch to be legal on a certificated airplane. Stewart Systems is strong enough to be legal with a glued seam only, and not over any structure.
John

[taylorukuk]

Looking through some Tcraft parts for sale recently Rob very kindly picked out the Dahlstrom for our project (I had no idea what it was)

[Carrieve]

I already have the fuselage covered so cutting into that will be a heck of job of starting over. Any ideas?

[Scott]

Covered and top-coated?
topcoat system?
certificated or not?

Invariably this will come down to what you're trying to achieve. Conformance with acceptable data means the dorsal fairing piece needs to be there ( although I can't point to a drawing or parts manual that shows this part) and the joint needs to be stitched or otherwise done in accordance with your covering STC, AC43.13 etc.

Having said that, if you've achieved a proper joint, and managed to shrink the fabric such that the transition is adaquatly tensioned and stable, I'm sure yours won't be the only example flying around without the transition piece.

S

[3Dreaming]

Just make sure it is safe, and that your IA is okay with it.