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Getting Ready to Main Rivet Wing Skins

NorthernRV4

Well Known Member
Well, a little later than I thought I'd be but I'm ready to rivet the top main wing skins on the port wing. Leading edge is fully riveted, and all all ribs are pop riveted and bolts torqued except the inboard 3 ribs which I'll leave until the wing is completely closed. In Canada we have to have an inspection before I can rivet the bottom wing skins in place.

I'm looking for advice to make this process easier and avoid potential pitfalls. Here's what I have so far.

1. I plan to back rivet using the Cleaveland 12" back rivet set. There's a tiny bit of misalignment due to the flange on the opposite side of the rib but this must not be a real problem since this is pretty standard procedure for top skins. I don't have the large face bucking bar they sell and I'm wondering if that's truly required for a nice finish, thoughts?

2. I plan to follow the rivet driving sequence Van specifies in the build manual unless there is a better way.

3. I've heard of builders using a heat lamp to warm the skin slightly during riveting but I don't know much about the in/out's of this. Is it worth the effort in the end?

4. I find there is the slightest misalignment of some, not all, dimples nesting together, it's just enough to make the edge of a rivet stand slightly proud so that a fingernail can catch it. I'm sure others have experienced this, how did you deal with it?

I can't wait to see this porcupine without it's quills!

RV-4 LH wing ready for riveting by James Soutar, on Flickr
 
Well, a little later than I thought I'd be but I'm ready to rivet the top main wing skins on the port wing. Leading edge is fully riveted, and all all ribs are pop riveted and bolts torqued except the inboard 3 ribs which I'll leave until the wing is completely closed. In Canada we have to have an inspection before I can rivet the bottom wing skins in place.

I'm looking for advice to make this process easier and avoid potential pitfalls. Here's what I have so far.

1. I plan to back rivet using the Cleaveland 12" back rivet set. There's a tiny bit of misalignment due to the flange on the opposite side of the rib but this must not be a real problem since this is pretty standard procedure for top skins. I don't have the large face bucking bar they sell and I'm wondering if that's truly required for a nice finish, thoughts?

2. I plan to follow the rivet driving sequence Van specifies in the build manual unless there is a better way.

3. I've heard of builders using a heat lamp to warm the skin slightly during riveting but I don't know much about the in/out's of this. Is it worth the effort in the end?

4. I find there is the slightest misalignment of some, not all, dimples nesting together, it's just enough to make the edge of a rivet stand slightly proud so that a fingernail can catch it. I'm sure others have experienced this, how did you deal with it?

I can't wait to see this porcupine without it's quills!

1) I really like using the Cleaveland 12" back rivet set when I did my wings.

2) I followed a sequence that Synergy Air taught me but I imagine there are many different opinions on this...Synergy's sequence worked but I was trying to eliminate some oil canning.

3) Do you have any oil canning when the wing is cleko'ed up? If not, no worries.
 
No oil canning that I can tell, I assume you mean an area where the skin can pop inward and stay there or pop out just the same. All seems good on that front and I hope nothing develops as I start driving rivets.

Curious, did you use the big round Cleaveland bucking bar when you back riveted?
 
No oil canning that I can tell, I assume you mean an area where the skin can pop inward and stay there or pop out just the same. All seems good on that front and I hope nothing develops as I start driving rivets.

Curious, did you use the big round Cleaveland bucking bar when you back riveted?

Your description of oil canning sounds right. Usually things just get tighter as you rivet, so if no oil canning when cleko'ed you should be good.

No on the big bucking bar...I had one of these.

BB30-Large.jpg

I talked to Mike at Cleveland and he said that the above bar would work fine...especially if I slightly rounded the corners to prevent any accidental dents.
I used the heavy end against the skins. Whatever bar you use, it should be easy to control and heavy...this bar is around 2 pounds (0.907185 kilo)

I took Mike's advice and my wings look great.
 
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Yes, I have that same bar from my Redbox kit I picked up from Avery tools at Airventure 2013 (wow time flies!) I was considering a home made solution but it's good to know I have something suitable already.

My biggest concern is how to deal with the rivets that don't seem to fit just perfectly flush. Is it permissible to run a #40 drill in the offending holes to clear away the edge so the rivet will sit perfectly? I've done this before and it just seems to remove the slightest of material which usually does the trick. I'm just more reluctant to do this on the main wing skins.
 
So my first attempt at back riveting the outboard skin did not go quite as I expected, or maybe it did...

I'm using the 12" straight back rivet set which means there is a slight misalignment of the rivet axis and the set axis. Just as I worried there is a tendency to clinch over the rivet (AD3-3.5, not too long) especially near the ends of each rib where it's not possible to flex the opposite flange aside. Are others experiencing this? I can't imagine this is considered permissible but is there a certain amount of clinching that is ok?

First back riveting of wing skin by James Soutar, on Flickr

First back riveting of wing skin by James Soutar, on Flickr
 
same thing

I did maybe 4 rivets and gave up and did it the "normal" way gun on the outside bar on the inside maybe it was me but I couldn't do it
 
I did maybe 4 rivets and gave up and did it the "normal" way gun on the outside bar on the inside maybe it was me but I couldn't do it

Same here. I tried the back rivet method a long time ago and couldn't get decent results. Others have succeeded, so I'm not saying it can't be done...
 
Good to know it's not just me. I'm seriously considering the offset back rivet set. Has anyone tried it? It's described as being harder to use but I think I'd be ok with it as long as I can align it to the rivet axis.
 
Good to know it's not just me. I'm seriously considering the offset back rivet set. Has anyone tried it? It's described as being harder to use but I think I'd be ok with it as long as I can align it to the rivet axis.

That was the one I used. I just couldn't master it.
 
What is Synergy riveting sequence?

1)

2) I followed a sequence that Synergy Air taught me but I imagine there are many different opinions on this...Synergy's sequence worked but I was trying to eliminate some oil canning.

I am about to rivet the top wing skins on my RV8. What is the Synergy's riveting sequence? Is it different than the instructions in the Vans manual?

Thanks.
 
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