LSA aileron nose skin rivets

[Frank]

Couple of questions:
1. What does the factory use?
2. What are the options?

On the LSA scratch build, plans call for 3/32 Monel pull rivets on the aileron nose and trailing edge.
Googling suggests Monel is a nickel alloy and I wonder why this is called for?
Plans do not specify flush but that seems what everyone is doing.

I am considering using Cherry Max CR3212 I think has aluminum sleeve and steel stem.
Not available in 3/32 diameter. But I think I might benefit from drilling out to 1/8 anyway.
Also planning on using the Avery pop rivet dimpler in addition to squeezer.

Thanks for any ideas and suggestions!

https://www.cherryaerospace.com/docs/catalogs/CA-1011.pdf

Screen Shot 2022-06-06 at 10.33.39 AM.png

[rodsmith]

I'm not sure why he is specifying monel rivets there. I checked my 4-place plans and he called for 1/8th aluminum pop rivets for the nose ribs and 1/8th stainless rivets for the trailing edge. Sounded like overkill on the trailing edge but that's what I used. I used the CR3212 rivets on the wings, in the few locations where I couldn't get a bucking bar, they are nice rivets. You could ask Bob, I learn something new every time I talk to him.

[Bcone1381]

My thoughts...
-I think (with 92% confidence) my Patrol kit's leading edge aileron rivets are countersunk.
-Is edge margin an issue if you upsize the rivet diameter?
-I looked up rivet strength, and SS and Monel are similar, monel has really good corrosion properties. Prime your SS rivets if you go that route.
-3/32 pop rivets are always hard to find for me when I get specific on things like material.
-Typical AN426 rivets have a 100 degree countersink. Lots of pull CS rivets have a 120 degree countersunk angle, which then you'll be buying a different dimple die set.
-Vans Aircraft hardware has a 3/32" cherrymax. Link below.

https://store.vansaircraft.com/ccr-264ss-3-2-cherrymax-rivet-rivet-ccr-264ss-3-2.html

[rodsmith]

Could have used some of those if I had been aware of them.

[Frank]

Thanks for that, Brooke! I hadn't been finding 3/32 flush pull rivets of any description. This could be the one!
I was thinking that upsizing would ease assembly of my imperfections.
But availability of 3/32 means I can keep the 1/8 strategy in reserve.

[OfTheWolf]

Frank
I used BSC - 34 pop rivets from Aircraft spruce. It is difficult as u point out to find 3/32 pull rivets. They are not flush. I did call and talk to Bob and he said you can drill out a hole in some steel plate slightly larger then the rivet and strike it w a pipe which will flatten out the head some I have not tried that yet but I may. The skin is obviously too thin to counter sink. I think after taping and covering even without attempts to make them totally flush it will be of no consequence as the nose of the aileron is largely recessed in the pocket rib.
David

[Frank]

David that's looking like a definite possibility. Can you post a picture of one of these on your test piece? I'd like to see what the expanded bulb on the back side looks like. Thanks I appreciate it!

[Frank]

I'm just now starting some test pieces using CCC-32 rivets from Aircraftspruce. This was suggested by someone on Facebook and fits the specs on the plans. Also testing the Avery pull rivet dimpler for the long-reach holes. One thing I notice with this and with the squeezer is the hole gets enlarged slightly when dimpling.
https://www.aircraftspruce.com/catal...erryRivets.php

[jaredyates]

I have used several of the ccp and ccc rivets, though I find the 3/32 aren't especially tolerant of an oversized hole. The 1/8 were much more secure.

[Frank]

The CCC-32 rivets fit loosely in no. 41 holes. When pulled, they expand and seem tight but don't exhibit a "bulb" or obvious grip over the backside of the rivet.
I also tried to drill one out but to no avail. Obviously needs stainless steel bits.
So I will continue research:
What should the "shop head" of a 3/32 flush pull rivet in dimpled holes look like?
What are the tools and techniques to remove these rivets?
Need to resolve these questions before actually riveting the nose skins!

[Frank]

This is what the business end of the CCC-32 rivets look like (.016 with .020).
Doesn't exactly inspire confidence.

[Frank]

This looks enticing. All aluminum.
But is it safe?

[rodsmith]

Countersink angle of 120 deg looks like a problem.

[Frank]

Mark Goldberg was very informative. Asked him what is used for factory aileron nose skin rivets. He said they use aluminum rivets from Hanson Rivet.

100% aluminum sleeve and mandrel.

I'll see if I can get some of these and try them out.

Thanks Mark!

[OfTheWolf]

Frank,
Thanks for sharing the info from Mark.
Here are some pictures. The last one on some scrap pieces and shows the underside of the rivet. None of them have been loose but they do sometimes come out crooked especially if you dimple the rib.
David.

[Frank]

Thanks David. There are lots of drawings of he ideal rivet out there, but very few photos. So when the bulb doesn't expand and grip like the drawings, you have to wonder. One reason I might go with non-flush rivets is the dimples enlarge the holes slightly and the clecos don't hold as well.

[Frank]

When you talked to Bob did he say anything about dimpling and flush rivets? Or did you get the impression he recommended protruding head rivets? Thanks!

[OfTheWolf]

Frank
Bob said you can dimple if you want to. He seemed overall a lot less worried about the rivets sitting flush than I was.
DV

[Frank]

Pictures of the Hanson PAAK302 aluminum rivets. Seems to form a slightly more expanded bulb than the CCC-32 steel rivet.
The grip length is .031 - .125, so the nose skin plus rib (.016 + .020) just falls in that range.
Drills out quite easily.
So I'm going with it.