Mid- Engine Modified Sports

[manta22]

Neil, there is a certain well known Australian racing car with a yellow frame.  It is a proven performance enhancing color.

McLaren? If so, that is NZ. Thanks, WW. 

Regards, Neil  Tucson, AZ

[Milwaukee Midget]

Neil, there is a certain well known Australian racing car with a yellow frame.  It is a proven performance enhancing color.

Are you referring to the car with the matching wiring harness?

[Speed Limit 1000]

Neil, there is a certain well known Australian racing car with a yellow frame.  It is a proven performance enhancing color.

Are you referring to the car with the matching wiring harness?

Yes the crazy ones.

[manta22]

I had to do some spot touch-up painting on the topcoat; missed spots were visible when I hoisted the chassis up on its side to start riveting on the stressed bottom panel. All I can say is my chassis is a "15 foot paint job".   

I did install one aluminum bottom panel this afternoon-- 85ea #4 Monel body/Inconel 600 stem rivets. These are bulbed CherryLock rivets that have excellent shear strength and they pull the panels up tight as the stem is pulled.

As an attempt to keep as much salt out of the rivet holes, I ran a bead of silicone down the chassis tubes where they contact the panel. I bought a few cans of a blue silicone RTV that comes in a pressurized can with a nozzle; press the nozzle sideways and the RTV comes out as a blue foam. I had never seen this stuff before but it turns out to be quite useful. The stuff is made by CRC.

The monsoon is back now. Fortunately my outside work is finished (I hope).

Regards, Neil  Tucson, AZ

[wobblywalrus]

A piece of monel metal was given to me to machine when I was an apprentice.  I remember it still.  That metal was tough.  I'll bet those rivets are strong.

[manta22]

WW;

You are among the few that have ever heard of the stuff.

Monel has been around since WW I but not many people are familiar with it. It isn't a steel alloy, rather it is a cupro-nickel alloy with high strength, toughness and elevated temperature tolerance. The stems are Incolloy 600, a high-temperature stainless steel alloy. I have some of it in sheet that will be my lower firewall.

These are Cherry CR2935P (NAS1738MW4-3) blind rivets and although they are only 1/8" diameter they are spec'ed as 895 lbs shear and 490 lbs tensile strength. The next one-- the main stressed panel-- will be riveted with lots of #5 (5/32") rivets.

Regards, Neil  Tucson, AZ

[manta22]

With apologies to James Whistler-- "Arrangement in Zinc Chromate and Black".

Regards, Neil  Tucson, AZ

[tauruck]

Whistler wishes.

You're another kind of artist.

I drool just looking at that canvas and it's a good thing you have air.
Popeye would buckle trying to do that job.

Very nice Neil. Thanks man.

[manta22]

Mike;

Thanks. Pulling those rivets by hand would be unthinkable. I put in 95 with my pneumatic puller but it was just barely able to break their stems. On the double pattern holes I'm using oversize rivets and these need the 4,000 lb pull capability of my air/hydraulic gun. I should be able to finish the panel today.

Regards, Neil  Tucson, AZ

[manta22]

I finished installing all the rivets in the bottom stressed aluminum panels today-- about 400 rivets total. Now I've started installing other stuff like the rear body pivots and lock pin receivers. It's getting back together-- slowly.

Regards, Neil  Tucson, AZ

[Milwaukee Midget]

As always, fascinating.

Wish I knew more about the process - so I'll just start asking question.

When riveting with this many rivets, are there issues with material flex that you have to compensate for?

If so, how do you do that?

Thanks, Neil!

[manta22]

Chris;

If you mean does the material compress as you drive it (actually, with blind rivets you pull the stems up into the body)- yes, a little, but the rivet pulls the two sheets together and expands as the stem is pulled. In addition, there is a bulge formed behind the last sheet that keeps the rivet body from falling out. Aerospace rivets also lock the stem into place so that vibration doesn't shake it out of the body.

Drilling a nice clean round hole of the proper size is important as well as using the proper "grip length"  for the thickness of the material. It takes too much pulling force to use a hand tool when you are using 5/32" Monel body & 15-7 PH stem rivets. I have to use my FSI "pneudraulic" gun for these types.

Using temporary fasteners such as Clecos is a must to keep all the holes aligned when they are drilled and again when they are riveted. Without Clecos, it's guaranteed that after a few holes, the panels walk off and the other holes don't line up.

Regards, Neil  Tucson, AZ

[Milwaukee Midget]

Got it - you also mentioned shear strength - I'm assuming side to side on the rivets.

You mentioned panels tend to walk without placement pins - Clecos in your case.  Do you need to pull the rivets up in the same sort of manner that you might torque down a cylinder head?  I could see a large panel with 400 rivets warping if you were to just start on one end and work your way across.

I could see when you're done, you'd wind up with a tensioned, stiff subassembly.

Thanks for the tutorial.

Chris

[manta22]

Your cylinder head bolt torque sequence is a perfect analogy, Chris.

Regards, Neil  Tucson, AZ

[tauruck]

Neil, Clecos are underrated. I use them daily.
In my case they live in a container filled with Acetone.
Resin inside the mechanism renders them useless.

I had this funny situation years ago. This is the story on how I got my air riveter.
I used to run this young guy's racing career. His family had an engineering company.
The had this "air" riveter and couldn't get the rivets to go from the plastic container out back
to the front.
They said it was mine if I could fix it.
I did.