Blind rivets in lieu of AN rivets

Hello everyone,
I'm not able to buck the 3 rivets forward of of the C-702 forwrd top skin on my RV-7 tip-up because of the underlying structure. I think it's a common problem...
A picture being worth a 1000 words:

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Sorry if this is a dumb question, but what blind rivets could I use in lieu of the AN426 AD3-6 and -7 rivets in this location.

Thank you,

Alain.

I'm almost there and have decided on cherrymax.

I think it is the revenge of the Engineer

More likely an outcome of CAD which may miss substructure or access.

We had similar and did similar, using Cherry's. The RV8 was more so, especially for skins around the top of the gear towers.

They can be driven; mine are. But when I looked, I couldn't remember how....

Looked a little closer & realized that I ground some, well, half-moon shaped tapered notches in that interfering cross bar (sorry; no idea on the part #). The notches look kinda like a very wide dimple or countersink would look if you cut the panel though the center of the c/s after the c/s operation. After seeing the spot(s), I probably used the corner of a tapered bucking bar to get in there. FWIW, mine didn't have enough room to get a pull style rivet tail all the way in without notching the crossbar, so....

I'm no engineer, so hopefully a real one will jump in here with an opinion. But I don't think the end of that cross bar is doing anything structurally, except directly in line with each rivet on the end of it. My notches are not full depth, and are more or less centered between the cross bar's rivets.

Charlie

Cherry Max

rv7charlie said:

They can be driven; mine are. But when I looked, I couldn't remember how....

Click to expand...

Maybe you followed the instructions in the manual and delayed riveting the heavy angle brackets and attachment of the roll bar until after the holes were riveted?

(And I think the small reliefs you ground into the brackets are mentioned also....)

What rivets specifically?

Thanks for the replies.
I probably didn't ask the question correctly...
I can't find the correct size blind rivets.
All blind rivets I can find seem to have a diameter too big to replace -3 size rivets, I can only find -4 diameter blind or cherrymax rivets.
Can anyone give me a reference or part number or even better a link for a website where to order ?
Thank you.
Alain.

Bonjour Alain.
I think you are looking for MK319-BS rivets
Diametre is about 7/64" and the head is small. They are often used in hard to reach spots on the elevator end ribs. I think there were some included with my -8 kit. Van's has them on their web site.
Salut

So Sad - - -

If you have gotten this far (probably a QB) and not prepared for clearance, the F705G may be so tight that you can not even use a Cherry Max. They require more backspace than you think.

I just got to these rivets last week and talked to Scott on the Vans Help line. He recommended that I remove the F705G (left and right) and install the rivets properly. That is what I did. One (big) caveat - if you have installed all the rivets as solid, then you won't be able to get to them for removal or installation without taking off the side rails that cap the longeron along the cabin side.

Look up the cherry max tech manual on their website and select the proper length, head, materials, and diameter.

I did not have to remove my rails, but did have to remove the installed roll bar. All together it took 20 hrs. Not a single boogered hole. Most of that was determining the correct tools and process, so if you undertake this to do it "properly" email me. Happy to let you know what I did with some pictures.

To your other question: Yes cherry max diameter will be -4 but do have some with a -3 CS head. I think this is the right length, you need to verify - CR3214-4-03. Purchased from http://gen-aircraft-hardware.com

Sorry, these were not the rivets I was thinking of. I see now yours are the ones which go through the longeron.

Yes, very common. My technique was to grab the first blind rivets out of my stash I could make fit. I probably drilled the hole out to 17/64 or something; I don't recall.

The plane ain't gonna come unzipped b/c of these three rivets.