Any last requests?

[Scott]

Good evening all
I'm just about to attach the top wing fabric. I've got the control cables in position and the pitot line in and positioned through the bottom fabric, ribs lined up as best I can, measurements and positioning for rib lacing (to miss cables spars etc., and anti chafe tape in place.

Anything else I should check/Not forget!?

Thanks
S

[NC36061]

Re: Any last requests?

Wiring for nav lights? Just in case you might want them later?

[PA1195]

Re: Any last requests?

Plus a second wire for LED tip strobe synch between wings?

Make sure that pitot line is leak-free.

Gary

[Robert Lees]

Re: Any last requests?

What's the white tape on the rib flanges? If it's anti-chafe tape, be aware that it's cotton and hence a moisture magnet (and I know you're legally not required to follow the STC) but it's not part of the covering STC (I use transparent sticky tape to allow the fabric to slide).

Also (and I can't tell from your photo) have you put some protection between the drag/anti-drag wires where they cross?

Rob

[3Dreaming]

Re: Any last requests?

Are the drag/anti drag wire oriented so they move away from each other when the wing has washout added?

[Scott]

Re: Any last requests?

Thanks guys
Here's my thoughts:
I fly at night in my 172, and certainly in this part of the world, even in clear air, you're flying on instruments, especially and critically, immediately after takeoff. So... I don't see this Taylorcraft ever being equipped to be safely flown in IMC, so no wires for lights.

Pitot: I'm using a single piece of poly tubing from the panel to the pitot, but good point.

Rob, the tape is Polyfiber anti-chafe per the manual which states "SUBSTITUTIONS WILL VOID THE STC AND YOUR AIRWORTHINESS" after a long section on using only PMA materials. Then it specifically says not to substitute other tapes. I hate the polyfiber tape, it doesn’t stick well and is expensive but CF-CLR will have a CofA so I don't feel a deviation from the manual is appropriate. Because I'm lacing the ribs, I decided to cover the whole rib flange, to ensure the lacing doesn't get damaged by the inside edge of the ribs. Not happy about this solution, but couldn't think of an alternative.

The tape by the way doesn't seem to absorb moisture, perhaps because of the rubberized adhesive but water beads on it (at least when it's new). Polyfiber says their tape will reduce the potential for corrosion! Anyway like I said not a fan but....

Thanks
S

[Scott]

Re: Any last requests?

Are the drag/anti drag wire oriented so they move away from each other when the wing has washout added?

Yes, drag wires on top
I used koroseal to both separate and lace the wires where they cross

https://1.bp.blogspot.com/-Dt1BxQOLeTc/WWL4qB6WUrI/AAAAAAAADmY/xJWaJi7sZC0TTpZwg325ijHR--9xxmFwACLcBGAs/s1600/DSCN5657.JPG

[PA1195]

Re: Any last requests?

"Pitot: I'm using a single piece of poly tubing from the panel to the pitot, but good point."

Do you feel confidant in the durability of poly tubing over metal? My experience is some synthetics can weather, become brittle, and crack when exposed to the elements and UV. Metal is almost forever...mine's 76 yrs young and still holding hands. I've replaced synthetic lines more than once in aircraft, and the cockpit run twice in my T.

Edit: How do I know when there's pitot line leaks? The plane indicates lower airspeed in flight than normal. Had it happen to me and a friend's PA-18 within the past month. Put a length of rubber tubing on the pitot tube, pinched the end shut and rolled it up some creating low pressure in the line. Should hold a steady airspeed if tight, slowly bleeds off if there's leaks. My left wing sourced static line also cracked in the cockpit but not sure about the effect of that in the scheme of things.

Gary

[Robert Lees]

Re: Any last requests?

....Because I'm lacing the ribs...

They should be wired. Do you have an STC (or Canadian equivalent) to deviate from the original design spec? Also, I can't see in the PolyFiber manual where it states to cover the rib capstrips with anti-chafe tape, and I have NEVER seen that on any aircraft.

I'm not being difficult, I assure you, but the post-war one-piece ribs were not intended to be laced. And that anti-chafe tape is cotton-based, which will attract moisture.

YMMV

[N96337]

Re: Any last requests?

but the post-war one-piece ribs were not intended to be laced.

YMMV

You've never seen a Univair rib for any of the Cub models then. There are plenty of them flying and no problems. I was told by our FSDO to go ahead and ribstitch if I can't find Tcraft wire, so have done a few that way. They do fine. and I usually tape the rib on a pressed rib. I've yet to see that tape ever create a corrosion problem and I've spent a fair amount of time in the salt air taking care of airplanes.

[Scott]

Re: Any last requests?

All good stuff, thanks for the thought provocations.

Here's what polyfiber says; "Any sharp edge or structural feature that might cut or poke through the fabric...." should be taped and, "NEVER use paper masking tape, duct tape, or aluminum-faced tape instead of genuine Poly-Fiber anti-chafe tape. All of these retain water and will bring about rust or corrosion on metal..."

AC 43.13.1B chpt 2 states "Care must be taken to insure that all sharp edges against which the lacing cord may bear are protected by tape in order to prevent abrasion of the cord."

Attached is a photo of a typical Taylorcraft aileron rib stitch partially cut by the rib flange (hey we know it would have probably never failed and outlived the fabric but that's not reason to repeat the problem).

I formed and de-burred the edges of all the wing ribs but the chafe tape is simply easy and effective assurance. Given that the lap joints between the nose, centre and trailing sections of each rib need to be taped, and the joints at the leading edge skin and trailing edges need to be taped, I decided to just tape the whole lot.

The aircraft was rib stitched when I got it and has a 337 in support of this change. I don't believe a reissue is needed. Canada and the US have a by-lateral agreement accepting each countries approvals for this type of thing. Additionally I believe in Canada substituting rib lacing for fasteners constitutes a minor modification supported by available and suitable data (AC 43.13). If not, I'm confident I'll be able to get an AMO approval similar to what I did for my spars.

Why all this..... well I guess it's a little like the screws in the leading edges, Wire, rivet & screw fabric fasteners were used in production because they were labour-saving, not because they were better. Those methods are clearly adequate, but I have always intended to rib stitch as I feel its the best alternative.

I stripped and media blasted every component including all the ribs, which then got phophoric acid cleaning/etching and alodine conversion, followed by epoxy primer. Polyfiber seems to believe its tape does not promote corrosion, but regardless, I'm confident those ribs will remain corrosion free.

I would have preferred not to use the tape but that's the rational behind my decision. Some of these things I guess come down to personal preference.

[Scott]

Re: Any last requests?

Do you feel confidant in the durability of poly tubing over metal? My experience is some synthetics can weather, become brittle, and crack when exposed to the elements and UV. Metal is almost forever...mine's 76 yrs young and still holding hands. I've replaced synthetic lines more than once in aircraft, and the cockpit run twice in my T.

Thanks Gary
Poly tubing has been used extensively in GA aircraft production for pitot/static lines for 50 years or so. What experience I've had has been positive, and certainly easier to R&I instruments plumbed with poly.

I hear what your saying and considered soft aluminium tubing, but in the end went with good quality poly. It's durable, virtually impossible to seriously damage, and easy to work with. After 40 or 50 years yes it gets a little stiffer, but then the aluminium tube I removed from CF-CLR was in a pretty awful state and the joints were made with neoprene hose which is definitely worse.

Because of the flexibility my thinking is I'll be able to run from the pitot to the ASI with no in-line connections. simple and leak-proof, and if it's inconvenient to remove in the future a union can be easily installed.

[PA1195]

Re: Any last requests?

Ok Scott and thanks for the expanded explanation. We'll find out in 30 or so years how durable your choice was (?). Do check for leaks periodically.

Still.......I'd cover from UV any exposed synthetic tubing. I'm resistant as well but sometimes yield to temptation. Plastic who knows their tolerance?

Great project and thanks for the documentation and inspiration.

Gary

[astjp2]

Re: Any last requests?

There is a 337 that I posted that is acceptable data to rib lace...Tim

They should be wired. Do you have an STC (or Canadian equivalent) to deviate from the original design spec? Also, I can't see in the PolyFiber manual where it states to cover the rib capstrips with anti-chafe tape, and I have NEVER seen that on any aircraft.

I'm not being difficult, I assure you, but the post-war one-piece ribs were not intended to be laced. And that anti-chafe tape is cotton-based, which will attract moisture.

YMMV

[Scott]

Re: Any last requests?

There is a 337 that I posted that is acceptable data to rib lace...Tim

Is it in the technical documents section? I haven't been able to find it.