Which way to put the shop heads

[jcoloccia]

Traditionally, you're supposed to put the shop heads on the thicker material to keep the thin material from deforming a bit when the rivet expands. On the VS and HS spar caps, is you put the shop heads on the spar cap side, they interfere a bit with the skin rivets. It's not a big deal. I have the technique down where you get the rivet started with the yoke just a bit off center...then the yoke clears enough that you can finish off the rivet and they turn out perfectly.

I'm wondering if anyone's asked Vans about this? If the manufactured heads were on the spar cap side, I think most of the interference would go away. Clearly, the manufactured heads for the hinge plates should go the other way around. With the added thickness of the hinge plates, I got into a situtation on the VS where I couldn't even buck the rivet. I had to partially buck it kinda' cockeyed, and then finish it off with the squeezer....it turned out fine but there's just no call for that

Short of grinding down the head on the thin-nosed no hole yoke, what have others done here?

[DGlaeser]

I put the shop heads on the spar doublers (horiz and vert) because that is the visible side - never thought about interference with the skin rivets. The spars are thick enough that deformation isn't really an issue.
The only place (so far) the instructions recommend rivet orientation is when you rivet the ribs to the wing spar - there they do want you to put the shop head on the ribs.

Dennis Glaeser
7A Wings done - fuselage coming...

[LettersFromFlyoverCountry]

Van's has acknowledged the tradition, but says there's no particular benefit from one over the other structurally. There are, however, other considerations. Access, for one.

For example, depending on where the the part is installed on the plane (somewhere in the fuselage, for example),you might have to drill it out someday, you'd kinda want the manufactured head exposed in that case. Other folks just plane like the manufucatured head exposed where passengers and other ooglers can see it.

And then there's riveting access. Yesterday I was building the "new" rudder and riveting the reinforcement plates to the spar. I'm using a TATCO squeezer. With the large yoke (not the longeron yoke, couldn't find one for the TATCO and stopped looking). You can't squeeze the rivet if you put the manufactured head forward, the flange of the spar will interfere. But if you reverse it, and use a longer flat set, you can reach it.

Of course, nobody will ever be able to see those rivets as the curved leading edge will cover it. So they'll just have to take my word for it that they're perfect. Just like every other part of the plane they can't see.

[DGlaeser]

Originally Posted by Bob Collins

And then there's riveting access. Yesterday I was building the "new" rudder and riveting the reinforcement plates to the spar. I'm using a TATCO squeezer. With the large yoke (not the longeron yoke, couldn't find one for the TATCO and stopped looking). You can't squeeze the rivet if you put the manufactured head forward, the flange of the spar will interfere. But if you reverse it, and use a longer flat set, you can reach it.

Of course, nobody will ever be able to see those rivets as the curved leading edge will cover it. So they'll just have to take my word for it that they're perfect. Just like every other part of the plane they can't see.

I like your reasoning
I believe I used my C-frame for many of the rivets on the empennage frames. It provides great access to hard to reach areas. I was surprised how often I ended up using it.

Dennis

[thallock]

Bob,
If you are still looking for the Tatco longeron yoke, then check out Brown Tool Co.

http://www.browntool.com/productsele...?productid=603

Tracy.

[lucdbedard]

I've been workinig on the wings of my RV7 for a few months, fluting, deburring, priming etc, it was now time to rivet the ribs to the spar

I have the spar installed vertically in a jig. I dropped the rivets in the holes and started bucking with the manufactured head on the spar and the shop head on the rib side (thinner material), rivet orientation never crossed my mind up until the very last rib.

My understanding of Vans instruction is reverse of what I did (manufactured head on the rib ) Of course it's friday night and I cant call Vans until monday, what do you guys think, is orientation critical in this instance ? I'm ready to drill them out and re-install them the proper way but I'm concerned that I might create more problems with enlarged holes etc....

[sf3543]

I'd leave them and move on. You are probably correct in that you may cause a problem by drilling out the rivets and wallowing out the holes. As I said, I'd leave well enough alone. VAN's would probably say it would be nice to have them the other way, but this is fine.

[jcoloccia]

Originally Posted by lucdbedard

I've been workinig on the wings of my RV7 for a few months, fluting, deburring, priming etc, it was now time to rivet the ribs to the spar

I have the spar installed vertically in a jig. I dropped the rivets in the holes and started bucking with the manufactured head on the spar and the shop head on the rib side (thinner material), rivet orientation never crossed my mind up until the very last rib.

My understanding of Vans instruction is reverse of what I did (manufactured head on the rib ) Of course it's friday night and I cant call Vans until monday, what do you guys think, is orientation critical in this instance ? I'm ready to drill them out and re-install them the proper way but I'm concerned that I might create more problems with enlarged holes etc....

It's a long wait to Monday, so if it makes you feel any better I'd bet 5000 to 1 that if you managed to get them all in without distorting stuff and making a mess of it (which it sounds like you did), Vans will give the usual "Do it right next time....build on".

[DGlaeser]

Originally Posted by lucdbedard

I've been workinig on the wings of my RV7 for a few months, fluting, deburring, priming etc, it was now time to rivet the ribs to the spar

I have the spar installed vertically in a jig. I dropped the rivets in the holes and started bucking with the manufactured head on the spar and the shop head on the rib side (thinner material), rivet orientation never crossed my mind up until the very last rib.

My understanding of Vans instruction is reverse of what I did (manufactured head on the rib ) Of course it's friday night and I cant call Vans until monday, what do you guys think, is orientation critical in this instance ? I'm ready to drill them out and re-install them the proper way but I'm concerned that I might create more problems with enlarged holes etc....

Orientation of a rivet is NOT critical. Yeah, it's better to drive the rivets from the spar side, but the ribs are thick enough that driving the rivet on that side isn't a big problem. If your ribs look good don't mess with them!!! You can find multiple reports on this list where perfectly good (but not perfect) rivets were removed with disasterous results. When you do your other wing you can put those rivets in the other way.

Dennis Glaeser
7A Wings done - fuselage coming...

[jcoloccia]

Originally Posted by DGlaeser

Orientation of a rivet is NOT critical. Yeah, it's better to drive the rivets from the spar side, but the ribs are thick enough that driving the rivet on that side isn't a big problem. If your ribs look good don't mess with them!!! You can find multiple reports on this list where perfectly good (but not perfect) rivets were removed with disasterous results. When you do your other wing you can put those rivets in the other way.

Dennis Glaeser
7A Wings done - fuselage coming...

Incidentally, I could be the poster child for what happens when you remove perfectly good rivets. I'm sick of rebuilding pieces of my empenage, quite frankly

Live and learn...