Don Terrill’s Speed-Talk

According to page 29 of the 2015 rulebook, it states that you can put in a 1.625 rocker or sill bar/tube on the rocker. It looks like the rules require a 6x6x.118 thick plate mainly to keep tube ends from puncturing the unibody, HOWEVER, if you put in the rocker/sill tube down first on the rocker, then put the rest of the structure welded to that, you would NOT need the 6x6 plate, because the rocker tube would be the element distributing the force from the tube ends, thereby eliminating the chance of tube end push-through. I seriously doubt that anyone could honestly tell me that an entire 4 ft sill tube on its side is going to simply push through the sill, or that the tube end notched to it will push through the lower tube.

Even in their example the A pillar and main hoop rests on the sill tube, with no plates depicted.

Thoughts?

The main thing I think about when reading NHRA rules about rollcages is they are meant to be interpreted for safety purposes first, structural second. In my opinion there shouldn't be a rollcage out there that isn't directly tied to a frame rail or outrigger of some sort. Welding a cage on 6x6 plates on top of sheet metal floor doesn't do much to help the framework of the car take the horsepower. Its will not puncture through the floor in a rollover though so in that respect that makes it ok. The NHRA and their insurance companies know best.

Looks like this is a hole in the rulebook. I am being told that despite being right from both a safety and structural basis, if techs don't see the plates you are done, end of story.
Unfortunately the car I am plating up is one of the early models and the way the sheet metal is formed, its less than about .028 in some areas due to the way it was formed and overdrawn. Blow through is pretty much assured. Ugh.

Just seamseal a piece of 1/8" plastic 6x6 to the floor around the pipe and paint it. As long as it looks right they wont check it. You and I both know a 4ft tube of metal is spread more even than a 6x6 plate. If you feel safe in it that to me is more important.

cgarb wrote:Just seamseal a piece of 1/8" plastic 6x6 to the floor around the pipe and paint it. As long as it looks right they wont check it. You and I both know a 4ft tube of metal is spread more even than a 6x6 plate. If you feel safe in it that to me is more important.

I haven't read the NHRA rules, but I do know this, if you are hurt or worse... your survivors [family] will not get any insurance! There will be an investigation and your cover up will be found. So the NHRA [or it's insurers] will not pay and you do not have any life insurance while racing [unless you have a specific rider for such], accidental ???. So for the cost and aggravation is it worth it? We all see and have seen things go seriously wrong at the track, our own fault or otherwise. Just something to think about, in the end it is your life and family. Harry

It's difficult to predict what a jury will do in a personal injury case where expert engineering testimony is relevant.
The burden:
1. Prove that the absence of the plate is what caused the crash: impossible, it's not supposed to do that at all, and the car was destroyed after this (loss of control) happened.
2. Prove that the absence of the plate is the causal factor of the cage collapse or intrusion by which the plaintiff was injured: very difficult from a scientific basis even with an "autopsy" of the wreck - but jurors are entirely capable of sympathy verdicts, and the plaintiff might lose based on being perceived as a cheater.
3. The tort-feasor is actually the person who designed/built the cage (who may have acted without the plaintiff's knowledge or permission), whom the insurance company will implead as a 3rd party to deflect jury attention.