Andy's Pacer restoration thread...

[stevesaircraft(Bri)]

Brian,thanx for sharing.Curious about your preference for Dekota ribs over Unavair? I have held them both in my hands and they both look fine but I prefer the Unavair for the pop rivet rib stitching.Rocket

Rocket...

I hate pop rivets for fabric retention.... Yes they are fast, but... Fabric likes to pull up when flying, you wind up relying on just the rivet head to keep your fabric in place... Stitching the air loads are across the entire rib with the cords pulling on the bottoms... Much better IMO...

Univair ribs can cut cords because of the stamped edge.. Dakotas are an extruded T section with nice smooth edges.. Way nicer for stiching...

MY opinion of course...

Brian

[Gilbert Pierce]

I use Univair butt ribs but Dakota Cub ribs for the rest of the wing for the reasons Brian listed. Ditto on not using fabric rivets.

[stevesaircraft(Bri)]

I use Univair butt ribs but Dakota Cub ribs for the rest of the wing for the reasons Brian listed. Ditto on not using fabric rivets.

Gilbert...

That is exactly what I am doing... (mentioned on post #64)...
I already have the two Univair ribs, been hanging on my back wall for a few years..

Brian.

[Gilbert Pierce]

I should have said And Dakota ribs, I knew you were using Univair butt ribs.

[rsrguy3]

We just pulled the fabric from a set of super decathlon wings, no pulled covering around any rivets, which suprised me. What I did notice was some ribs flanges seemed compromised(deformed). I really like the idea of lacing better than rivets.

[Steve Pierce]

Drilling those spinning rivets are a pain. I like the Univair butt rib and Dakota Cub for the rest. Call Keith at DC and ask for the layout for drilling the holes for the drag and anti drag wires. We mark them and drill on the bench prior to assembly.

[Vagabondblues]

I am confused about the mixing of ribs. For starts, the Univair ribs are approved under STC. With the application of the STC can you replace just one rib, or are you required to replace all the ribs to be in compliance with the data? I assume that the STC was required because the stamped rib is basically a different design than the built up piper truss rib. Also confusing is the data in Univair's application listing which shows the ribs FAA approval basis as an STC. Does that imply that are they really approved as a direct replacement PMA'd part for the original piper ribs? Yes, on the application listing there is a note which reflects that statement, but the note is not present on all the rib applications, just a few. I have also checked the FAA PMA listings on their website and did not find a PMA for Dakota Cub rib assemblies for the PA20 other than the two (LH,RH) outside aileron rib. With all of this in mind, how are you guys getting this set up approved? Are you making out a 337 for the one butt rib on each side under the STC and then are you getting approval for the remaining DC ribs under a field approval. Of course, not needed if PMA'd for your application?

I also get it that you do not like pop rivets, but can't you also use martin fabric clips with the Univair ribs?

[Steve Pierce]

The ribs are STC'd. There is a list of the original Piper part number and it's subsequent Univair or DC replacement.

[Vagabondblues]

STC SA98CH on the FAA website does not show the 16, 20, or 22. I would like to use the DC ribs, wonder why they are not listed on the FAA listing for the STC?

[Steve Pierce]

Give Dakota Cub a call, might have been an add on or I might have documented the wrong STC number.