Pulled Rivet Future

6S4 Hugo · #1 01-01-2010, 03:26 PM

I'm still in the "looking-at-it" stage on the RV-12. I like the idea of pulled rivets (speed and ease), but had some concerns about long term lifespans.

With a solid rivet, there is less chance of water invasion into the interior of the wings and other surfaces. Pulled rivets seem to have a natural reservoir to collect water. Additionally, if the remaining stem falls free, you would have the 12,000 stems banging around your aircraft. (I'd hate to have to lift the wings, on end, and have to shake the little beggars out

) You would also be open to large amounts of water infiltrating into the wings and fuselage.

Do the plans call for filling the rivet holes with epoxy, or is paint sufficient to seal the holes? What about those builders who opt for a polished finish?

I Googled and could find nothing on this. I did find some solid vs. pulled rivet discussion boards, but was wondering if this could be what has led to the problems with the Zodiac and the wings.

Andy J · #2 01-01-2010, 04:41 PM

I don't think the mandrels are going to fall out. From the Gesipa website: "Add to this PolyGrip's locked mandrel core and you have a weather tight rattle resistant fastener."

Info on the rivets here: http://www.gesipausa.com/polygrip_aluminum.htm
P/N GSMD41-43APG

The holes are not very deep so I don't think water would be there long. I have not found any instructions to fill them. There was, I think, a thread discussing this for aesthetics.

I have only pulled a couple thousand so far, so I'm no expert, but I feel comfortable with them.

WilburD2 · #3 01-01-2010, 04:52 PM

I am quite sure that the life expectancy issue on pulled vs. solid rivets is something the Vans engineers will be keeping an eye on over the life of the factory demo bird. As for the corrosion aspect.. Thats usually fodder to restart the primer debate all over again.
But I look at it this way; normally you're not going to be flying in the rain as an LSA unless you can't avoid it. With the removable wings, chances are its going to get trailered home to a garage or covered parking anyway. At least thats what I would do.

Geico266 · #4 01-01-2010, 05:08 PM

The rivets are designed to hold the remaining mandrel tight. It is not going to fall out.

I filled all of my rivets. Not a big deal at all, and it will look better IMHO than having all of those holes staring at you.

6S4 Hugo · #5 01-01-2010, 05:18 PM

Quote:

Originally Posted by Geico266

The rivets are designed to hold the remaining mandrel tight. It is not going to fall out.

I was wondering how long (primary vs. cosmetic) pulled rivet use in aircraft has been around.

Has anyone heard of any follow-up on the wing failures on the Zodiac? It seems that they started occurring around the same time. Could this be a fatigue factor that has laid dormant and just now is rearing its ugly head? (Maybe I'm just to familiar with "Pop" rivets, and so don't have much faith in them. It's just that it's my arse that's being held up with those rivets.)

I wonder if Vans will ever offer the option of flush rivets on the -12. It would be interesting to see what the performance figures would be with less drag.

MartySantic · #6 01-01-2010, 05:42 PM

The pulled rivet that is used in the 12 will outlast both of us. You can fill the heads, as Larry has mentioned for aesthetics but it is certainly not necessary.

Comparing the design of the RV-12 wing and spar to the Zodiac is quite simple. Even a non-engineer type will be able to ascertain which design is superior by merely looking at the skeleton.

Stop procrastinating and get a buildin'

You will be amazed with the RV-12s fit and finish.

6S4 Hugo · #7 01-01-2010, 05:45 PM

Quote:

Originally Posted by MartySantic

Stop procrastinating and get a buildin'

I plan to start in 2010 if the financial gods smile upon me. (Tomorrow, if'n I win the PowerBall jackpot

)

Thanks to everyone for the input.

VHRV12 · #8 01-01-2010, 07:12 PM

Quote:

Originally Posted by Geico266

The rivets are designed to hold the remaining mandrel tight. It is not going to fall out.

I filled all of my rivets. Not a big deal at all, and it will look better IMHO than having all of those holes staring at you.

Larry, what did you use to fill the rivets?. Is there a weight consideration? I am concerned about the steel stem of the rivet causing dissimillar corrossion within the rivet and then transferring to the structure. On the other side of the coin here in Aus, the Victa Airtourer is assembled with pops, and has been flying since the sixtys with no real problems, and rivet technology has probably increased considerably in recent years. Thanks for your info.

N941WR · #9 01-01-2010, 07:51 PM

Quote:

Originally Posted by 6S4 Hugo

...I wonder if Vans will ever offer the option of flush rivets on the -12. It would be interesting to see what the performance figures would be with less drag.

Not likely. Van's talked about how nice it was to design an aircraft where access behind the rivet wasn't a requirement.

Heck, I would be happy if they would start offering the other kits punched to size and dimpled so we didn't have to match drill and de-bur every hole but I doubt we will see that either.

Mel · #10 01-01-2010, 08:02 PM

Quote:

Originally Posted by 6S4 Hugo

Has anyone heard of any follow-up on the wing failures on the Zodiac? It seems that they started occurring around the same time. Could this be a fatigue factor that has laid dormant and just now is rearing its ugly head? (Maybe I'm just to familiar with "Pop" rivets, and so don't have much faith in them. It's just that it's my arse that's being held up with those rivets.)

I wonder if Vans will ever offer the option of flush rivets on the -12. It would be interesting to see what the performance figures would be with less drag.

First off, the Zodiac problems aren't remotely related to pulled rivets. There are hundreds of Zodiacs (pre XL) that have been flying with pulled rivets for many years. There is also a multitude of other designs by Murphy, Monnette, and others that have been flying with pulled rivets for decades.

As far as performance goes, there should be no difference between pulled and solid rivets. I think what you really mean is the difference between flush and round head rivets. (Both are available in pulled and solid rivets.)
In the 100 mph speed range, you would be hard pressed to see an improvement with flush rivets.

If you really want to use flush pulled rivets on the -12, you could do that by going E-AB. To use solid rivets would require a substantial redesign.