danswofford

I'm welding in a roll cage to NASA spec. Their general rules seem to call for welding a 9 sq. inch plate to the end of any attached tubing. My experience with oval track cars was that we would weld the tubing directly to the frame with no plate in-between. Anyone know?
Dan

Falcon

You might want to post that over on the NASA forum.
www.nasaforums.com

gkmccready

I've always seen the cages welded to plates; atleast the cages in my RX-7s, and the various other cars I've looked at over the years. I admit I've not looked closely at the C5 or C6 cages, but I expect all the rules (SCCA/NASA/CASC) say you have to use a plate to distribute the forces.

NASA Pro Racing has a Yahoo! Group that you could ask on -- used to be Ken @ IO Port was the rules **** for the NorCal guys and he was quick to answer questions... he made me build a pretty insane cage for my '87 RX-7 TurboII...

glen

Axelrod

In the rules it does clearly state that each mounting point of the cage (to the frame) requires a plate.

The required 360 weld around the base of the tube to the specified thickness frame plate in question does a few things:

1. Eliminates the possibility of any improprieties with regard to "frame strengthening" -- this is the standard -- no more, no less.

2. Lessens the chance of weld contamination over a larger square area and distributes the force over 3x the area of just the tube.



The full NASA rules can be found here:

http://www.nasaproracing.com/rules/ccr.pdf


Look on page 74 within Adobe's page numbering system for this particular issue.

davidfarmer

tube frame cars (NASCAR, Trans AM) don't require plates, as the "frame" is thick walled tubing. OEM frames, while very strong, are made of very thin metal. You need to reinforce the areas where the cage mounts, or it could literally rip a chunk of steel out of your frame in a hard impact.

AU N EGL

I think if you build an SCCA approved cage you will be ahead of the game.