fatbillybob

GBaker,
I'd work for free and with you. I'm facinated by the science but live in so. cal.. My physical skills are good but I've been out of school so long I forget what the apple hitting Newton on the head was about.

RedlineMan

Joe;

Now THAT is a discussion. Before, to me, you just sounded like a Bird on the Wire, squawking, making noise. Prove It, Prove It, Awwwwwk! He's full of ****, he's full of ****, Awwwwk! Now you have fleshed out your thinking a bit, and that is a REAL starting point.

It sounds like to me you have been very lucky in your driving incidents. Sounds like they were relatively longitudinal, linear impacts, but THAT IS A GUESS. Those are the "safest" impacts to be involved in, and where ANY safety device works best.

Can we start by trying to agree on a basic point?

It is the driver projecting out of the seat that causes most street injuries?

gbaker

Thanks, but a grad student would have access to some smokin' simulation software.

2008 SAE paper: "Finite Element Analysis of Head/Roll cage Impacts."

chris walrod

Taken from the Abstract of the SAE paper link I posted earlier:
Test methods and test devices were constructed to study and develop objective understandings of the effect of vehicle seats and seat belt systems for the purpose of improving or anticipating improvements to a motor vehicle rollover protection system. Overall, it is determined that occupant displacement from the seat in rollover conditions is affected by factors associated with a vehicle seat belt restraint system and seat

From this, it appears this very paper may shed light on your question.

gbaker

Thanks for the reminder, Chris.

cooleyjb

The discussion is almost entirely meaningless in this case. All that can come of it is anecdotal evidence and armchair science. Both of which provide one thing only. A bunch unsupported facts and unproven opinions. That is the point that you are missing in all of this. When you go out and say that something is bad the way you have, you should be able to support it. All you can give is an opinion, which in teh world of auto safety doesn't mean a thing. So yes all this "squawking and making noise" as you put it has proven one thing. You are merely stating an unproven opinion when talking about cages during street use. That is all I have been saying and you just keep getting defensive.

kurt M

I know it is not the objective of the tests when they are performed but watch the tests that the highway safety institute does. There are lots of carefully staged well filmed impacts to look at and you can see how much the crash test dummy moves around and where it goes. It would not take a PHD in anything to envision where a roll bar or cage side bar would be. There are many head on, rear end, side and offset videos. I bet you could do a low cost study using this footage and look to see if the dummy’s head intrudes into a superimposed cage bar space.

I have no dog in this hunt other than to get people to use 6 point systems and well installed seats at least in DE cars. Rule making for dual use cars is hard to do as there are many aspects to it.

RedlineMan

Joe;

I understand what you are doing, and I am not defensive, personally. You have not STATED it clearly enough (at least for me) until this point. You are not arguing the merits of my ideas, just the methods. I tried to lead you into my thought process so you and everyone could see where I'm coming from. You are not interested. So be it.

You are saying that unless someone spends gazzilions of dollars to test a specific something, repeatedly, until a reasonable database can be established, and all kinds of math can then be applied to explain it on paper, that you will not support any notion on the topic. I think that is being rather obtuse.

Sir Isaac Newton did not need a PHD in physics to figure out what happened when he was beaned by the apple falling. He simply observed, and thought. Like Kurt, I too do not feel that one needs to be Anointed on High to be able to SEE what happens in sled test videos and real world crashed vehicles. I've seen LOTS of both.

While I agree with an underlying premise of what you are saying, in that there are often many counter-inuitive surprises lurking in physical occurences, that does nothing to diminish the value of reasoned inference, and simple, basic observation. Science, after all, starts with a thought, then an observation.

IF it is true that the real danger in an accident is the occupant(s) projecting out of the seat. And, IF it is true that an irregular shaped object stands to be more injurious. And IF you put that object more proximate to the occupant(s), then to me, it stands to reason that this represents a more dangerous situation for a street driver. I don't see where this is not patently obvious from what is already available for all to see?

You can argue against that all you want, but that does not make the forrest go away. The forrest being the huge stack of physical evidence available in the reems of crash videos available.
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As an aside, it is interesting to me that PCA can dissallow the use of both 3-point and harness used in conjunction because no one has tested it. Then, in the same breath, they OK the use of the lap belt portion of the harness in conjunction with the 3-point, even thoiugh I am not aware that anyone has tested that? Further, using that logic, how can they then recommend the use of a cage in a street car when THAT has not been "tested?"

Looks like I'm not the only one you could sink your "teeth" into.

sjanes

On a modern car I would agree with this, but on an 20-30 year old car, I'm not sure this is the case. With the lack of proper crumple zones in older cars, I do think that cockpit intrusion (especially in a t-bone accident) is a real concern.

kurt M

Sad to say but I bet that many standard bolt in cages will not add all too much protection to a T bone. Side impact is one place that I feel many cage systems are lacking. It is hard to protect for a side hit. There is little room for give before metal meets meat. One door bar strung from one bolted point to another with or without reinforcment of knee type bars and/or bracing will add some but how much?

Do off the shelf bar and cage makers test the products they sell or just build to a standard of tubing size, wall thickness and basic rules of construction?

TR6

Wow, I go away for a few days and look at this thread I started. The good news is that I think I had my question pretty much answered back on page 1 of the thread. 6 pt it is for me. Thanks everyone!

sjanes

I agree, but unfortunately I didn't realize this at the time that I bought the cage and I'm considering having it replaced with a custom cage.

My original decision to put a cage in a DE-only car was because I came within inches of being T-boned (by a car sliding backwards). It was the first time I even considered that I could be hurt doing DE, which I then had to weigh against the chances that the "safety" equipment could injure me on the street.

cooleyjb

Nope, I'm not saying that. I'm saying that anecdotally it can be argued either way. However without any testing, all it is, is simple arm waving and guesstimation.
Actually you miss the biggest part of what Newton did. He tested his hypothesis found supporting evidence and was unable to falsify it. That last part is the key part of what he did.
Yes, science does start with a thought. However someone who has done any research into the history of science will also know that most thoughts/experiments are falsified or are failures.Not disagreeing with that. I never have. I never will. I have however argued that while there is an increase in danger concerning some variables of accidents, there is also an increase in safety in other areas.


I know this. I've said my piece to the powers that be. I think there are a number of odd things that the race organizations do. I play by their rules but voice my opinion on how things are run occasionally.

fatbillybob

So true. Bolt-in lack enough bolts and lack triangulation or the simple reinforcements like weld-on tabs to the chassis that add an amazing amount to the integrity of almost any cage. But it is all about compromise. Sadly, More people would weld cages for improved performance than would do it because it was safer.

fatbillybob

Elegant and makes sence to me.