Super D

They all had the argument that the HANS can be rendered ineffective if the belts slip off, and that the R3 can be used without a harness so it can be used in any car. And they all were under the impression that head motion control was equal to the HANS.

I'd like to see some data showing the R3's performance in a standard seat-belted car. I'll bet it's a pretty long time/distance before it has any effect...if it is effective *at all*. We've all seen the 35mph crash tests and witnessed how far the dummies travel while belted in...

What about the ISAAC? I ruled it out when looking into this a few yrs ago, but how does it compare currently?

gbaker

Super D,

Head motion control doesn't matter because nothing--HANS included--can hold the head vertical in a big hit. The odds are that your head is going to hit the wheel. The belt slippage issue can be addressed by capturing the belt, as in the ISAAC design. I think the only advantage the R3 has is that you can jump from car to car and that it can be used with 3 point belts.

Man, am I ever biting my tongue. We just got out of the lab yesterday after completing an entire series on this whole belt/load/motion/slippage thing with multiple designs in multiple crash labs. If we say anything now people are going to say, "Show me the data!", which we won't have for a few days, so hang in there.

Video also. I'm not a fan of video as it can be misinterpreted, but sometimes it's the only way to tell the story. Some of it is jaw dropping. Redline Man is going to go nuts.

Our best estimate based on all we know thus far for the top three designs (ISAAC, HANS & R3) side-by-side on any sled, for three different crash scenarios is:

1. Pure Frontal Impact (Zero degree offset)
HANS beats the ISAAC system slightly. If you crash the HANS with the 4-belt Schroth-type harness it performs even better. When I was last at the Delphi lab with John Melvin he told me they could get the upper neck tension loads under 1,000 Newtons with the right tuning, although they risked elevated shear loads. That is a huge number. It's great for bragging rights but it has limited practical value because once you get beyond ~150Gs fatalities are caused by internal injuries.

R3 is a distant third.

2. 30 Degree Offset Impact (Considered the most severe; generates upper neck loads higher than pure frontal)
ISAAC and HANS tie in the measure of upper neck tension, with the R3 a distant third. However, creeping into the picture are the issues of belt slippage and how well the product protects against lateral loads. This is not a pure lateral test, but the sin of 30 degrees is 0.5, meaning that the lateral component of a 70G 30 degree offset impact is 35Gs. That's a lethal hit, and there are ways to isolate its effect. We have hard data and video on this and we were surprised at the results--stunned might be a better word. Redline Man is going to go nuts because it deals with a subject near and dear to his heart.

3. Pure Lateral Impact (90 degree offset)
There is no modern test series for this scenario, which tends to blow up seats and dummies. As an extension of the offset test, the ISAAC should perform best.

TD in DC

Greg,

You are such a tease . . . .

TD

gbaker

We would encourage anyone on the verge of a purchase decision to sit tight. These tests produce massive amounts of data and it takes time for everything to be distilled into something meaningful.

Also, we enjoy a good reputation among racers for being straightforward with product information, and we do not wish to tarnish that reputation. I'll admit to bouts of enthusiasm, but if I start sounding like a salesman, please throw something at me.

sleder

Greg, I applaud your patience...I have none!!!

racergreg

Gregg -

Can you please comment on RedlineMan's diagram showing the shape change scenario? It looks like the Isaac would just roll forward along the shoulder belts and allow the head to continue forward.

My apologies if this is covered on the Isaac website, I have not yet viewed all of the videos. Just point me to the right place if it's there.

Thanks for your honest comments, I am eager to see the new data.

gbaker

I have none either, we just have no choice on the timing.

Super D

Greg, would you mind posting a link in this thread to information we can review once it's released?

Thank you. This is important stuff.

As for video, I know whatcha mean. Some friends involved w/the side HR seat testing showed me non-public footage and it was shocking. Never thought a lateral hit could produce such horrifying deformation of a human. Do you get involved with the side HR seat testing as well these days? That's some fascinating stuff. Keeping the head from moving too far while controlling the decel rate to help prevent internal damage. So complicated are these safety prevention issues. After seeing much of this, and watching simple crashes end up deadly, and complex crashes end up minor, it makes me think you *have to* outfit yourself with the best safety measures possible and then...you need to be lucky.

DanS911

Must ......have.........info.........

gbaker

Sure.

The belt connector of the Isaac system is designed to roll forward with the body during an impact. For our first crash test we rigidly fixed it to the belt. The resulting problem was that it held the head back as the body went forward, so we loaded the head in the opposite direction. The idea is not to hold the head up in a vertical position, which nothing can do, but to hold the head onto the top of the neck regardless of the angle.

BTW, the angle of the dummy's neck when a HANS device is in place on the 70G impact is about 60 degrees off of vertical. With an Isaac system it is about 80 degrees. With no protection is it about 100 degrees--the head is between the dummy's knees. The idea of the HANS device holding the head up only works on the kiddie sled HANS uses at the PRI show.

At 70Gs a 200# driver loads the belt to seven tons and the head with helmet effectively weighs over 1,500#. In the lab they strap down the dummy's arms because, if they did not, they would get ripped out of the shoulder sockets on the rebound. At this level of performance you could hit something, have your arms and legs ripped off yet still survive, and it would be considered a success.

I don't mean to sound morbid. The point is that at large loads the body is just a big piece of Jello inside of a rapidly decelerating rigid box. If one can control the energy dissipation the driver can survive, but it won't be some neat, clean process you envision afer talking to the safety device salesman. It will more resemble politics or making sausage.

gbaker

You info junkie, you.

racergreg

Thanks, Gregg. One more question, then: is the basal skull fracture caused by extension of the head from the body, or extreme forward angle of the neck from vertical (chin to chest)? I thought is was the latter. And if this is the case, is this an area where the HANS is superior to Isaac (60 deg vs. 80 deg)? Not trying to be argumentative, but I'm trying to make an informed decision, and you seem to be a straight shooter. Thanks!

gbaker

Sure. Forums are great for getting feedback, but impractical for getting out the word. Once we get the videos reformated and condensed for Web traffic, and the load data presentable, we can provide a link.

Scary isn't it? The most violent one I have ever seen was a 100G blast. The dummy came so far out of the seat he slammed into the fake firewall and blew out his knees. The shoulder belts completely collapsed his chest and you could see the helmet shell vibrating from the head loads.

The good news is that an amateur racer can get for a few thousand dollars today a safety system that was not available at any price 20 years ago, and it can be good for some major hits. They won't like it, but at least they will wake up to complain about having to build another car.

Geo

The in-house testing I described would be 100% paid for by the manufacturer, so not cost to HR.org. I understand the liability issue and that is why the set-up of a separate but related corporation to establish minimum standards and issue the pass/fail.

The thing I am concerned about with having the manufacturer certified requirement is that who determines the validity of the tests, the uniformity of the tests, what the standard is/should be? And what is the penalty for cheating?

Now, saying all of this, I realize I'm dreaming up a lot of work for someone. I say someone because someone else has already dreamed up too much work for me in other areas and I cannot be a "doer" here. Given this, I'm appreciative of what is being done/has been done. But if I had the opportunity, I'd love to see SFI be a non-issue.

Super D

Yep, that's the most important thing.

Funny, before I started looking into this, a friend in pro racing told me he had paint on his helmet from the passenger side upper cage bar from glancing off a wall during a race. Now I believe him. I also think he cheated death on that one, so does he.