Pull rivets

[epapa]

When I built my RV many years ago I had my son home to help with the riveting. I loved the smooth flat head rivets. Now I have a problem trying to do it by myself. I never liked the Zenair aircraft due to the pull rivets but I am considering doing that on my LSA wings. I have watched the Zenair construction at OSH and it sure goes quickly. Has anyone done that yet and what do you think of it? I would probably use the same rivets that Zenair Aircraft uses.

[Archer39J]

I'm not at all familiar with the LSA design, but I would think it was designed to use solid rivets same as the Patrol and 4-Place. I wouldn't go substituting solid for pull without some engineering substantiation from the designer. I recall reading a story about a RV kit that was effectively ruined because someone used pull rivets throughout. They are also significantly more expensive than solid rivets.

[Chris In Milwaukee]

We had a nice conversation about this in 2007 in the "old Bearhawk group". Here's a link to the conversation:

https://groups.yahoo.com/neo/groups/...s/topics/67837

Interesting stuff in there. Perhaps not all the answers you're looking for, but good conversation.

Also, a unique view on pulled rivets from Budd Davisson:

https://groups.yahoo.com/neo/groups/...s/topics/61669

[Zzz]

I believe there is undeserved stigma with pulled rivets. Their composition and strength varies widely depending on your application. You can buy them in different grades and mandrel materials. Solid rivets are great, but you have to uphold a pretty high standard of personal workmanship and practice or they're compromised too.

Do you ever hear of Zenith wing skins, or any other part of the airframe ripping off in flight?

I think pulled rivets suffer stigma because no one wants to deal with the shit people will give them based on... the stigma. Sure feels good to sink a perfect pop rivet with a pneumatic riveter. They do make flush pulled rivets, which I plan to try for use on my cargo door skins.

[Chris In Milwaukee]

There is something to be said for the "kerchunk-sshhhhhh".

Can't say that I've heard of a Moose wing flying apart, either.

[Mark Goldberg]

Bob has stated that on our LSA kits builders can use ccc-32 pops on the bottom skin. Those are stainless pops. Mark

[epapa]

Thanks Mark.

[Flygirl1]

We used pull rivets for the wing tips, the door skins, boot cowl, interior floor and probably a few places I've forgotten about. I think they look great and with the pull rivet gun, installation was a breeze...mostly. You will want to be careful and keep the gun, if you use one, straight to the rivet as it has a tendency to skip off across the piece your working on. ;-( I guess as far as doing the whole wing, wow. That's a lot of pull rivets, but I would imagine a whole lot less stressful than bucking a rivet that many times. Every pull of the trigger was stressful for me until I could see no divit with the rivet. ;-) As others have said, those using pull rivets have yet to loose any skins in flight. Just don't skimp on the necessary amount of rivets. Too few in certain places and your likely to loose that piece, no matter which rivet you use!!

[epapa]

I am glad Bob had said they could be used on the bottom skins. That simplifies things a lot. I think I will contact him.

[Bearhawkdoc]

Pulled rivets lack the strength of driven rivets and this must be accounted for in the engineering. Zenair and others have purposefully engineered their aircraft to use the pulled rivets. It's not as simple as a one for one exchange of the two. This would be a very dangerous thing to do without the proper approval from the engineer/designer. Notice Mark stated that Bob approved pulled rivets for the bottom wing skins on the LSA, not the entire wing. So using pulled rivets on structural applications should be avoided without explicit approval from Bob.

[Chewie]

Well it makes sense if you think about it: the bottom skin is the high pressure side.