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Wing Leading edge attach

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Daniel S.

Well Known Member
All-
I'm reasearching my next steps a bit. It's been discussed a bit that the solid rivets attaching the leading edge are quite a pain. Are there any serious drawbacks with using the cherrymax pull rivets here? I believe the correct rivets are MSP -44 / 43 Monel Cherry rivets.
 
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Thank you for that link! Are most folks putting these rivets in backwards (manufactured-head on the thicker material vs. Manufactured-head on the thinner material)? I know it would be nearly impossible to get a rivet gun in there :eek:. But what about using a bucking bar drilled to accept a AN470 squeezer set & back riveting? Wouldn't that cure the issue with deforming the rib flanges? Plus be text book correct in the rivet application? Opinions & experience welcome here.
 
Not so hard using solid rivets

I riveted my leading edges about a month ago and it really wasn't that difficult. My helper ran the gun and I had the small tungsten bucking bar, taking advantage of my long skinny arms to reach in through various lightening holes. Bucking "blind" (required for some rivets) was not too difficult here. Sometimes I had to use the "dimple in finger" method to check the set rivet (after setting the rivet, press a finger against the shop head, then withdraw your hand and check the size and shape of the dimple in your skin).

I was prepared to use CherryMax but ended up not needing a single one!

I haven't tried back-riveting an AN470 as you propose, but I fear it might not work. It'd be interesting to know if it does!
 
help my confusion here...

everyone in this thread is referring to round-head rivets. But the leading edge skin attaches to the spar with flush rivets. So, are you all talking about the attachment of the rib flange to the spar web?

Curious minds want to know, thanks
 
The flush rivets attaching the leading edge skin to the spar flange are a piece of cake to set with a squeezer. What folks are talking about here are the universal head rivets that secure the aft flange of the leading edge ribs to the web of the main spar. You can access them only through lightening holes, and the center ribs are particularly hard to reach, but as I wrote, not that bad either.
 
Thanks all!
As always, there is awesome info out here on VAF. There are a bunch of options out there for this step. I'll have to noodle on it for a bit before taking the plunge. ;)
 
I just finished my last leading edge a few weeks ago. I'm like Shannon, I bucked as many as I could with the factory heads on the forward side of the spar. My arms are stubby, like a alligator. I ended up using some blind rivets on the middle rib flanges. All came out fine.
 
Daniel S. said:
Are most folks putting these rivets in backwards (manufactured-head on the thicker material vs. Manufactured-head on the thinner material)? I know it would be nearly impossible to get a rivet gun in there :eek:. But what about using a bucking bar drilled to accept a AN470 squeezer set & back riveting? Wouldn't that cure the issue with deforming the rib flanges? Plus be text book correct in the rivet application? Opinions & experience welcome here.
Click to expand...

Daniel, I had this exact same thought process about 5 years ago when I did this on my leading edges. I had an old hammerhead that I polished up and drilled for an AN470 rivet set, just like you're thinking.

100_5003%20(Small).jpg


I used an offset mushroom rivet set to "backrivet" the rivets with.

100_5009%20(Small).jpg


So how did this method work? Honestly, I had mixed results. I had to drill out quite a few of the rivets and try again. Why? Because when you're riveting, the bucking bar normally bounces on and off the rivet with each blow of the rivet gun. It happens so fast... 2,100 beats/minute... that you don't see it or think about it. And it doesn't matter. With flush rivets or bucktails, it isn't an issue. But in this case, with round-head AN470 rivets, if the rivet set moves a fraction of an inch between blows, the edge of the rivet set hits the top of the rivet and you end up with cuts or creases in the rivet heads. It must be held precisely in place for success. And that's hard to do. I had to drill out quite a few rivets and try again.

You can see all my pictures and discussion on the subject starting here. Scroll down to the bottom of the page:

Riveting Leading Edge to the Wing Spar

I was able to achieve some success with this method, on some of the ribs. But it's not without it's difficulties and challenges if you do this. More details are in my log. Would I do it again? I might, if I had an experienced helper to assist with either the bucking or riveting. Otherwise, I'd just use pop rivets and build on, as I eventually did with some of the middle ribs. Good luck with your work. :)
 
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Bruce-
Thank you sooooo much for the feed back & info on your experience! I really appeciate you sharing that! I'm still noodling this one over. I think I'm really leaning towards getting in there with CherryMax CR3243 oversized rivets (in proper orientation) and calling it a done deal. I've been looking at a bunch of other builder's sites & I'd have to say from the looks of it, most all folks who are shooting these rivets in reverse orientation (shop head on thinner material) are ending up with deformed ribs, gaps and dings. I still wonder how it would work out if I sacrificed a tungsten bucking bar & drilled it for a 470 set. If that one is even possible... Either way I feel comfortable going at this step, it's going to cost me an extra $100-$150 anyway. It's a plane who cares about cost ;)
 
problems i had

the solids with an off set set factory head on bottom- need to grind side of set or it will hit the rib and not be centered on the rivet. cherry max - the puller hits rib so i tried the little piece of metal that avery sells it is flat on top and at an angle on bottom to throw the puller away from rib. the shorter cherrymax in the thinner locations seemed to work ok but the longer cherrymax had the stem break early and had to be removed but they broke so early it was no problem.I ended up with the end rib all solids the two inner ribs 3 solids and some cherry max and some LP4-4 and LP4-3 if i had to do it again i would grind an offset set put the factory head down and find a good helper with a tungsten bar on the top. one of the ribs is fartheraway from the rib so cherry max works fine there it seemed that if the puller was straight the cherrymax pulled fine but with the puller at a angle they broke early the LP rivets did not have a problem with being pulled useing the off set piece of metal.
 
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Bill-
Thank you for the info... I just got the "new" little / close quarters rivet puller and "wedge" from those guys. I'm wondering if that will do the trick here with the Cherry max. Thoughts on that combo? I'm a bit away from actually doing it but I'll have to do an update when I get there.
 
close quarters

i only tried the close quarters and the wedge once but it seemed the puller didn't like the cherrymax and the wedge because it slipped on the stem so try it on scrap first. I wanted to use solids but cannot find a reliable helper so i used this combination of solids and pulled rivets. the wedge worked best for me if held paralled to the spar and the puller horizontal to the spar on the wedge. I wanted to use all cherrymax instead of LP rivets but once i had a few snap early i only did the longer pulled rivets in cherrymax that the puller could get on straight I don't remember if i had the wedge and puller in the above relation ship when i had troulble or not as it took me a while to see that was the best way to hold the wedge and puller and by this time i was using LP rivets. if you do waqnt to try LP rivets you will need to order the longer one as they are not in the kit. the kit only has LP4-3 no LP4-4
 
Daniel S. said:
Bill-
Thank you for the info... I just got the "new" little / close quarters rivet puller and "wedge" from those guys. I'm wondering if that will do the trick here with the Cherry max. Thoughts on that combo? I'm a bit away from actually doing it but I'll have to do an update when I get there.
Click to expand...

I used this close quarters rivet puller (without a wedge) on MSP-type pull rivets to install my leading edge with no problems other than the rather hard pull required to "pop" the monel stems.

I really like this puller. I bought this one after my Stanley brand puller started requiring disassembly about every other rivet to remove the rivet stem, and I was getting close to closing my first fuel tank, so I thought I'd give the close quarters one a try. The only reason I haven't thrown the Stanley away is that I rarely throw away anything...
 
Could you please tell more about this close quarter rivet puller? Unfortunately the link does not work anymore.
Best regards
Flo
 
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