The Cessna 120-140 Association Forum

Posted: **Sun Jul 09, 2023 8:25 pm**

Hello All:

My 120 has the SA4-89 Wing metalization STC but oddly two of the drag wire sets (inboard and outboard) have been deleted.

I have searched the forums back and forth and haven't found anything other than Bill Rhoades made some sort of post a long time ago that I cannot find that states that you can delete out the drag wires without compromising safety (I've read the wing STC PDF a dozen times)

Some STC’s must have called for the removal of the steel drag wires. If the fabric was removed and then
the drag wires removed, you immediately had a wing a bit limber, spaghetti-like. One owner at least
confirmed that his is twisted and lumpy from such a likely cause, but the plane flies like the others anyway.
From our supposing, we believe that the drag wires should have been left in to retain the wing shape at
least until either the top or the bottom metallization was secured to the structure and then it would have
been safe to remove the wires. They weigh about 8 pounds. Bill Rhoades published the information in one
of the Technical inserts to the newsletter about why it was okay to remove the wires when the wings were
metalized. I can still see mine, not all of them, so the weight change would have been less than noted if
they had been removed.

Does anyone know where to find this technical insert? Any way we can find any of the drawings for any of the STCs?

Thanks!

Posted: **Fri Jul 14, 2023 10:07 am**

If you use Facebook, message Ken Morris (his picture shows him standing in front of his C-140A). Ken and his wife have restored several 140's and can possibly help you with your question and the information you seek.Their business Taildragger Aviation owns the STC for utilizing pop rivets for attaching fabric to C-140/C-120 wings, and they've visited the drag wire issues in the past.

Additionally, you can also contact David Lowe at Lowe Aviation located in Sacramento, KY (you can find his telephone number on AirNav by looking at his airport information for 80KY). Give David a call, he's quite knowledgeable about the C-140 and the STC's utilized on the design. David has helped quite a few of us in the past.

Posted: **Tue Jul 25, 2023 7:34 am**

When was researching 120s ahead of a buy, I seem to recall that there were about 5 different wing metallization STCs over the years. Some purportedly retained the drag wires, some did not. Did not pursue further, but am guessing that unless the STC mandates or permits their removal, they are expected to be there.

The Cessna 120-140 Association Forum

Metal Wing STC + Drag Wires?

Metal Wing STC + Drag Wires?

Re: Metal Wing STC + Drag Wires?

Re: Metal Wing STC + Drag Wires?