John Brown

Bolts versus welds is a stupid thing to argue about. Either can be as strong as the other. If the bolt is the right size and the joint is properly designed. Lots and lots of very important things use bolts. Airplane wings. Helicopter blades. Elevators. Car wheels.

Veloce Raptor

So what? Specious comparison at best. None of those are designed specifically to save your life when the SHTF.

As I said, $50 head? Buy a $50 helmet.

cr207

the problem with the airplane and helicopter analogy is that helicopter and airplane bolts go through a lot more scrutney and testing then the bolts used for roll cages unfortunately. It is all about money. They can charge $80k for helicopter blades, I tend to think they are spending a little more time finding a the right bolt with the correct tensil strength.

RedlineMan

I'll take a stab at that;

THIS IS PURE CONJECTURE ON MY PART.

I don't know what a sled test costs. I don't know how difficult it is to schedule one either. I can't imagine either is easy to manage. If I had only the money/time for one test, it would most definitely be an offset test. They are the deadliest, and probably the hardest to model, anylize, or predict.

I don't know all the ins and outs, but I do know that Isaac has tested their device numerous times, with excellent results. They also eventually paid to have their device tested to the SFI standard, assumedly to prove a point, and knowing it would ultimately not be "certifiable" under the current statutes. I believe a HANS was also tested concurrently, perhaps as a baseline for comparison to a unit that "met" the standard.

I'm also willing to surmize that you COULD indeed predict with at least fair certainty that a device that performed well for offsets would perform at least as well or even better for straight on hits. They are the "easiest" to control in my understanding.

I would hope that a lot of others would do the same, most notably PCA. With some of the ideas I see them come up with, I'm not sure they possess the techincal knowledge to make it work. Unless you are extremely thoughtful on his stuff, you stand to make things worse, not better. If it was te insurance companies pushing it, it wouldn't surprise me. Not the first time they have pushed something on us all that was not completely worked out yet. To wit, the air bag!

chrisp

If bolt strength was an issue they would increase the mounting plate size and spec larger bolts. I think an M10 bolt (class 10.9) has something like 24,000 lb minimum yield strength. Multiply that by the number of bolts in a mounting point and the load shared by the adjacent mounting points and I doubt that hardware failure is the concern.

SundayDriver

I think a closer analogy is this...

2 men jump off a bridge, each with 2" of "tether".
Attachment to the person is the same for both and it is a hard foam cocoon which will absorb shocks like the inside of a helmet.
One tether is a nylon or polyester strap - limited stretch.
One tether is a damper.
Attachment to the person is the same for both (you pick how, except not around the neck please)
They both jiump.

Who comes home for dinner. I think they both do with the same level of, or lack of, injury.

Again, I don't deny that the damper is better. What I question is whether it has any real world benefit.

ltc

You are probably correct. I am probably just wrapping myself around the axle, thinking as an engineer and leaving common sense in the backseat.....then again, it's how I make a living.....I am paid to only see/find mistakes and not see beauty or things done well.....it's an odd job, I know.

The HANS has always bothered me, especially the "evolution of recommendations and designs" regarding the retentive (or lack thereof) nature of the belts staying on top of the collar.....it's been a long path.
But again, I don't see how the device works in certain scenarios, I only see how the device might NOT work in certain scenarios.
Yes, I realize nature abhors perfection and prefers entropy.

My apologies.

FlyingDog

Isaac has not been head on tested, but its 1300N score in the offset test indicates that it should pass the head on test with ease (spec is 3200N for both tests).

Isaac won't pay for the head on test because they feel it's pointless if they still don't meet the single point of release (and paying a large licensing fee) to be certified.

HANS complains about Isaac posting fake test results where the HANS cannot stay in the harnesses. Despite several requests from Gregg at Isaac, Howard at HANS cannot clarify how the tests were faked or show any decent resolution videos of a HANS staying in a 3" harness.

NASA's response to protests of the Isaac not being allowed is (paraphrased) 'If you don't like it, race elsewhere'.

RedlineMan

This sort of goes with what I was saying.

That's kind of funny, eh? Part of the fee that Isaac paid to have the test done was to cover the cost of having the Delphi test engineers make the HANS fail so Isaac could lie about it?

garrett376

So, to summarize... the feeling is that because it doesn't have a "sticker", it won't pass? Don't you think they'd use language that is more specific if that is what is required? I can only hope. Colin, I think you're a PCA scrutineer - your thoughts?

fatbillybob

This is my read on the subject too. I also have a problem with sanctioning bodies who restrict the maximum welded contact points to a chassis for the exact reason of "how many times out of 10 would the average weld fail". If you add in extra gussetting to the a piller and b piller and in some cars like a vette the OE rollover hoop or the dashbar to the A -piller buttress, you can make up for potentially unprofessional welds that we know are looking really good when covered in paint!

Circuit Motorsports

Nothing against the Isaac device but I wouldn't let it pass.

It simply does not meet the SFI 38.1 standard or the FIA standards.

gbaker

I meets the performance standard (by a wide margin) of both, but it does not meet the design standard.

Sorta like a Porsche not meeting the Yugo standard.

gbaker

Agreed. The intent of this rule is unclear.

ltc

It's all about the SFI sticker....actually the $ the sticker generates (I do not know the exact percentages, but on a $125 rib/chest protector, it's about $15 more for the same unit with the SFI tag)

This past season in karting, a spec was approved, SFI 20.1, for chest protectors for younger drivers (in the event of a crash where their sternum hit the steering wheel/column).

Now, there are lots of chest protectors that work (Kevlar body armor would also work), but it's simple. Don't see an SFI 20.1 label and/or they don't recognize the device as being on the list, you are failed at scrutineering.

A lot of parents had to go out and buy new safety gear with that little label.