Blind vs Solid Rivet

Hi All,
I am about 15 hours deep into the empennage kit and just starting to get to permanent rivets. Are the solid rivets stronger than the blind rivets? Some spots seem much easier to blind rivet, but the directions say to use a solid rivet.

Cherrymax

I didn't stay in Holiday Inn so take this for what it's worth.
Always follow Van's design. They have the FEA to know what changes can be used.
Only one pop rivet is as strong as a solid rivet. Cherrymax.
That said, Vans does allow a pop rivet in some places like the last hole at the trailing edge.

For structure, regular pulled rivets can't replace solid fivets. Only Cherrymax can typically replace solid rivets, and not in every hole of a line of rivets.

On the RV-4, it was allowed to substitute the 3/32” solid shank rivet with a CS4-4 pulled rivet on the bottom wing skins. It was said to be 10% stronger because of the larger size. The finish wouldn’t be as smooth though.

Michael Henning said:

On the RV-4, it was allowed to substitute the 3/32? solid shank rivet with a CS4-4 pulled rivet on the bottom wing skins. It was said to be 10% stronger because of the larger size. The finish wouldn?t be as smooth though.

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Thought I'd try this on a 3/32" dimpled hole in a test piece just to see how proud it would sit. Was AMAZED at how flush a CS4-4 would sit in a 3/32" dimple. It may not be perfect, but once primed and painted, bet you can't tell the difference. Sometimes the simplest of things elude me until someone post something like this and you have an "ah-ha" moment. Thanks Michael!

Michael Henning said:

On the RV-4, it was allowed to substitute the 3/32? solid shank rivet with a CS4-4 pulled rivet on the bottom wing skins. It was said to be 10% stronger because of the larger size. The finish wouldn?t be as smooth though.

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IIRC it was allowed to use the smaller MK319BS rivet which needed a 7/64 hole rather than a CS-4-4 rivet in a 1/8 hole.

Given that nothing was pre-punched in those olden days the larger 1/8 holes could start getting into edge distance issues. The early instructions allowed that on the whole wing.

I would use an 1/8” hole, and appropriate dimple die, it will sit even nicer.

There is going to be a few more places in the future where you may consider a pulled rivet. On the wings, you may choose to use pulled rivets attaching the leading edge to the spar. I've had to use a couple for the wing skin and rear spar where the new aileron doubler gets installed. I've also used one inside the fuel tank. Wirejock is right cherrymax are very strong. You would be wise to read up eventually on pulled rivet types. I did up a solid/pulled rivet comparison spreadsheet that listed all the shear strength, grip length and rivet/pin material. I also bought 1-2 cherry max rivets of each size and length. This became extremely handy for the handful of times you will run into a snag and didn't break the bank.

I always emailed Vans to double check if a particular pulled rivet type was acceptable for the area I was working on and that quick reply went in my build binder.

I have no data for the NAS1097 rivets, but seriously doubt that they are as strong as the rivets we use elsewhere. The body is, but since the heads are smaller, they'd pull through with a serious shear load.

For the standard rivets, twice as many -3 rivets on 1" spacing are slightly stronger than -4 rivets on 2" spacing.

Dave

David Paule said:

I have no data for the NAS1097 rivets, but seriously doubt that they are as strong as the rivets we use elsewhere. The body is, but since the heads are smaller, they'd pull through with a serious shear load.

For the standard rivets, twice as many -3 rivets on 1" spacing are slightly stronger than -4 rivets on 2" spacing.

Dave

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NAS1097 rivets are commonly used by Boeing on skins. Some of the fuselage skins are .080" thick.
The problem with using a cherry max besides the cost is that the stem and lock ring are steel, the body is aluminum. Differential metal corrosion. I worked on twin otters on floats in the Caribbean and the cherry rivets would only have the body remaining, everything else disappeared.
Also if you never had to remove a cherry you're in for a experience. That stem and ring are hard. We used a high speed grinder and a tiny ball rotary file to get the ring out. One slip and you screw up a skin.

The strength of a NAS 1097 is easily found. And where would you used 2" rivet spacing? Are you a structural engineer?

Tommy123 said:

The strength of a NAS 1097 is easily found. And where would you used 2" rivet spacing? Are you a structural engineer?

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........2" spacing when attaching a stiffener to a fuse skin; on a doubler for an inspection plate are two examples...... with a NAS1097, no I'd not personally use those for these cases, at least not repeatedly. To get out of a jam, yeah one or two. Pretty much 99% of the time however, I use -3 1097s for nutplate installs....

Being from the part 121 world when building my 7 those big head rivets looked clunky to me. Oh well, I'm a firm believer in doing what a much more qualified person than me engineered. Substitutions should not be taken lightly in primary structure areas.
Funny thing is that when at Braniff confronted with a non routine repair we would often use our experience to formulate a repair then call engineering who would do a structural analysis and approve the repair and draft drawings to match it. The engineers at Braniff were much more available in those days, at Northrop they hid, and you had to know the secret knock to get into their lair.