Helmet Support?

[R. Pare]

Originally posted by Gregg Baker:

So let's do this the easy way.

No, let's not. We want you to back up your claims with real data and facts, not innuendo.

Originally posted by Gregg Baker:

Get the test data from HANS and look at the videos. They will tell you what happened regarding the belt slippage. Then look at the load data. Any F-sub-z value in excess of 4.0kN is a dead dummy--doesn't matter whether it was during the primary impact, the rebound, or when everyone was out to lunch.

Doesn't matter when??? It most certainly DOES! Especially if the timing is due to circumstances forced upon the test results by the cockpit layout, and not an inherent flaw in the design of the HANS when used in in the typical formula car cockpit.

It may well be possible/probable that more care need be taken in the installation/use of the HANS verses some other devices, and if so, we need to establish the whats and whys so that those who are using them can double-check their own installation.

As regards Justin Wilson's belt slippage - the facts seem to contradict your statements here, especially as regards the belt force vectors of a properly installed system. If his belts slipped off without him hitting anything, then it can only be due to improper installation, or a flaw in the design or construction of the particular unit he was using at the time, NOT a flaw in the basic HANS design, as you seem to be continually trying to push.

Many of us here have been full-time engineers/participants in the field of race car design and dynamics, some with over 40 years of experience. We've seen all sorts of claims over the years concerning some new super-duper product that will cure all our woes. 90% were worthless, and many were outright dangerous. We've been there, done that.

So now it's your turn on the hot seat!


Please back up your statements.

[John Robinson]

Gregg,
I was very curious about your product after seeing the conversation going on here, so I visitied your web site. From what I read here I expected to see the dampers attached to the car somehow. But I now see this is not the case. They are held by the shoulder belts.

Now not being an engineer but yet a mechanically oriented thinker, how far does the head move as the roller slides up the belt and finally stops against your shoulders? Is the length of the damper adjustable for various seating positions? Wouldnt this also require the shoulder straps to be very tight? How much chaffing of the shoulder harness occurs with normal use?

I am only trying to learn more about your unit. I did the same with all the others I knew about before I bought my Hans, but if your unit is better, then I would be foolish not to use it.

Thanks,
John

[Gregg Baker]

RP,

I am going to give you an opportunity to review your comments before I reply.

-----------------------

John,

Good questions. There is a rather interesting story behind the belt connector and dampers. Rather than yes/no answers now, let me get back to with the whole story

--------------

All,

Have a great holiday weekend. Go fast, stop slow and God bless America.

[ccambern]

Without getting into the argument, a couple thoughts:

It seems like the two major concerns with the Issac are: A. It will bottom out, either in extension or compression, during a crash. B. It will prevent speedy driver egress.

The former shouldn't be an issue unless the rollers somhow manage to go too far away or too close to the body, thus moving the device out of its operating range.

Why not attach the shocks directly to the driver with some sort of harness and saddle? This would allow the shocks to move with the driver and allow the designers to predict exactly how much travel is needed to prevent them from bottoming either in extension or compression. It would also allow egress with the device still attached.

As for the HANS, although the belt slippage issue is a bit scary, it seems like somthing that could be easily fixed. I think some people have used a cross tether on their shoulder straps. Another suggestion might be a ledge that runs next to the outside edge of the belts, keeping them on top of the saddle.

I know a few people who have tried the HANS- one in a lay-down F500, and two others in RF98s. The F500 guy loved his, and the FF guys couldn't get comfortable. Personally, I don't use anything right now.

-Clark Cambern

[carl correll]

The HANS, as originally designed, had a ridge to retain the belts. These were deleted from the new formula car designs. The cars that I encounter usually have belt spacing of 9 inches. Far too wide for the HANS. The mounts need to be relocated in some way to work properly.

[Gregg Baker]

Originally posted by John Robinson:
Gregg,
I was very curious about your product after seeing the conversation going on here, so I visited your web site. From what I read here I expected to see the dampers attached to the car somehow. But I now see this is not the case. They are held by the shoulder belts.

Now not being an engineer but yet a mechanically oriented thinker, how far does the head move as the roller slides up the belt and finally stops against your shoulders?

John,

The head can move forward a great deal, as the product is designed to limit head loads, not head position. People have been talking about “head restraints” for so long there is the misperception that in order to limit the load one must limit the position—not true.

Is the length of the damper adjustable for various seating positions?

The damper is not adjustable. But because they work based on velocity, not position, position is not critical. Our rental systems have helmets with the mounts preinstalled with no previous knowledge of the driver’s size or seating position, and have been used in everything from formula cars to stock cars. For the individual customer, the instructions take this subject into account by describing the optimal position for the helmet mounts. We have developed a kids version which uses shorter dampers. This keeps everything proportional to the smaller anatomy. As junior grows, the dampers can be swapped out for longer ones.

Wouldn’t this also require the shoulder straps to be very tight?

Not really. The belt connectors are just along for the ride. Their location on the belt is a proxy for the top of the shoulder blades. Loose belts will make for higher loads everywhere, though—the head and the rest of the body.

How much chaffing of the shoulder harness occurs with normal use?

The crash belts showed no unusual wear, and we have received no reports from the field of any problems. The lower connector rolls on/under the belt, rather than slides.

I am only trying to learn more about your unit. I did the same with all the others I knew about before I bought my Hans, but if your unit is better, then I would be foolish not to use it.

I’m not a salesman, so I’m going to say something that will make a marketing department choke: If you like your HANS, keep it. It is a safe product, and if it is comfortable and your belts are okay, why change? However, if you move between cars having different seating angles, or drivers of a different size use the same car, an Isaac may be more convenient.

Thanks,
John

You’re welcome.

[Gregg Baker]

Originally posted by ccambern:
Without getting into the argument, a couple thoughts:

It seems like the two major concerns with the Issac are: A. It will bottom out, either in extension or compression, during a crash. B. It will prevent speedy driver egress.

The former shouldn't be an issue unless the rollers somehow manage to go too far away or too close to the body, thus moving the device out of its operating range.

Clark,

A. This is all a matter of geometry. The dampers do bottom out in extension, but not in compression. The stroke of the dampers is dictated by the geometry of the anatomy and the mechanical components of the system, i.e. the distance from the top of the shoulder blade to the ear (approximately) less the component geometry leaves the available stoke. By the end of the crash event the dampers are bottomed out in extension and the system becomes, in effect, a very rigid head restraint. Compression is not an issue because the helmet mounts are located such that the piston rod is slightly extended when the helmet is against the headrest.

B. We recognized from day one that the concept of a head and neck system which was, in effect, part of the harness assembly had pros and cons. The principal pro is that there is nothing to hang up on car parts on the way out. This is not a trivial issue, especially in closed cockpit cars. We have spoken with members of track safety crews and all like the idea of there being one less thing to drag out of the car.

I had the chance to conduct an unscientific survey when I was last on track. During a delay I asked a grid worker what they would do if they had to get me out of the car. They said, "Looks simple enough, but if I couldn't figure it out in about two seconds, I'd just cut the belts."

The driver can disconnect very fast. Our 12 year-old is on video doing it upside down.

Why not attach the shocks directly to the driver with some sort of harness and saddle? This would allow the shocks to move with the driver and allow the designers to predict exactly how much travel is needed to prevent them from bottoming either in extension or compression. It would also allow egress with the device still attached.

It’s in the patent application. There is no reason one could not include a damper in a Hutchens-type device, for example—or replace the HANS tethers with dampers for that matter. We chose not to take that route because we had two design objectives: to develop something as safe as the best existing head restraint, but which did not have the drawbacks of classic head restraints. All these drawbacks derive from the fact that they must be worn. They can be uncomfortable, if not painful; must be kept tight in order to work properly; and, in the case of the HANS, must be sized to fit the driver and the seating position. Then you get to the convenience issues. The Hutchens is cumbersome, and you need to take it off in order to peel down your suit in hot weather. The HANS is something else to drag around the paddock, you cannot lend it to another driver unless they happen to be your size and the car is similar, and it can be a bit warm in hot weather. All these problems disappear once the system becomes part of the car.

We could provide a product which is worn by the driver, and would do so if the demand were there.

As for the HANS, although the belt slippage issue is a bit scary, it seems like something that could be easily fixed. I think some people have used a cross tether on their shoulder straps. Another suggestion might be a ledge that runs next to the outside edge of the belts, keeping them on top of the saddle.

I know a few people who have tried the HANS- one in a lay-down F500, and two others in RF98s. The F500 guy loved his, and the FF guys couldn't get comfortable. Personally, I don't use anything right now.

-Clark Cambern

It's a good idea to use something. Anything is better than nothing.

[Gregg Baker]

Originally posted by R. Pare:
</font><blockquote>quote:</font><hr />Originally posted by Gregg Baker:

So let's do this the easy way.

No, let's not. We want you to back up your claims with real data and facts, not innuendo.</font>[/QUOTE]You and I are on the same track. We both agree that it is best to examine the data.

I already noted above that HANS won't release the test data to the media, so they surely won't release it to us. Without the data I can't prove I'm right. But with the data you can prove I'm wrong, and I may be. That's why I suggested you get the data. They should give the data to a HANS supporter such as yourself.

</font><blockquote>quote:</font><hr />Originally posted by Gregg Baker:

Get the test data from HANS and look at the videos. They will tell you what happened regarding the belt slippage. Then look at the load data. Any F-sub-z value in excess of 4.0kN is a dead dummy--doesn't matter whether it was during the primary impact, the rebound, or when everyone was out to lunch.

Doesn't matter when??? It most certainly DOES! Especially if the timing is due to circumstances forced upon the test results by the cockpit layout, and not an inherent flaw in the design of the HANS when used in in the typical formula car cockpit.</font>[/QUOTE]First, the timing does not matter because the yield strength of any material is not a function of time. If 900 lbs. of tension is applied to the base of your skull you're going to die, and you won't care what time it is. I'm sure this is not what you meant.

I see your point about the cockpit layout, but it is unlikely that Delphi can't put together a representative cockpit layout for its own tests.

It may well be possible/probable that more care need be taken in the installation/use of the HANS verses some other devices, and if so, we need to establish the whats and whys so that those who are using them can double-check their own installation.

As regards Justin Wilson's belt slippage - the facts seem to contradict your statements here, especially as regards the belt force vectors of a properly installed system. If his belts slipped off without him hitting anything, then it can only be due to improper installation, or a flaw in the design or construction of the particular unit he was using at the time, NOT a flaw in the basic HANS design, as you seem to be continually trying to push.

It's not a flaw in the design, it's a characteristic of the design. HANS already admitted in the above-cited e-mail that the belts came off. Since the lateral supports have been removed from the earlier design, as posted above, it's easy to picture this happening in a high-G offset frontal impact. It may well be that the resulting loads were not fatal, but they were probably higher than would otherwise have been the case.

Many of us here have been full-time engineers/participants in the field of race car design and dynamics, some with over 40 years of experience. We've seen all sorts of claims over the years concerning some new super-duper product that will cure all our woes. 90% were worthless, and many were outright dangerous. We've been there, done that.

I agree completely. Perhaps I spent too much time in aerospace and biomechanics, where blowing smoke will crash a plane or injure a patient, but it gets very deep in the racing industry and I would suggest everyone do their homework.

So now it's your turn on the hot seat!

Please back up your statements.

Show me where I'm wrong.

[Gregg Baker]

Originally posted by John Robinson:
Gregg,
I apologize. I was not aware of your product when I spoke to the Hans people. I specifically asked them about several other systems.

Having said that, will you be at the SARRC next weekend at Moroso? Will one of your devices be there?

john

John,

Please, don't apologize. Many new products are becoming available and it's hard for the recreational driver to keep up. Even the pros are having a problem.

We will not be there, but look for a ground-pounding GT1 Cutlass with "Terry Borcheller" printed over the door. It belongs to Andy Fox who is an SCCA instructor and has used his Isaac in several cars. He tows a dark blue enclosed trailer behind a black dually.

Our rental helmet inventory is depleted, so we put out a call for volunteer racers to show the product and Andy chimed in.

[kgjevre]

In follow-up testing on the 70G Delphi sled the belts slipped off the HANS every time they hit it.

What is your source for this claim?

Now the facts:

1. It is a fact that the belts repeatedly slipped off the HANS device in the offset frontal sled tests at the Delphi lab in December. The dummy died. It is not a marketing claim, it is a fact. If the user thinks this is not important, that's their choice.

2. Hubbard/Dowing, Inc. has not released the test results to the media.

3. We did not conduct the tests, Delphi did. The belts were repositioned by HANS personnel.

Again, what is your source for this claim?
Has this (claimed) test data been released to anyone?

If you don't believe it, ask Hubbard/Downing, Inc. for the raw video and load data from these tests.

So let's do this the easy way. Get the test data from HANS and look at the videos. They will tell you what happened regarding the belt slippage. Then look at the load data. Any F-sub-z value in excess of 4.0kN is a dead dummy--doesn't matter whether it was during the primary impact, the rebound, or when everyone was out to lunch.

I already noted above that HANS won't release the test data to the media, so they surely won't release it to us. Without the data I can't prove I'm right. But with the data you can prove I'm wrong, and I may be. That's why I suggested you get the data. They should give the data to a HANS supporter such as yourself.

You made this claim, so why don't you back it up with the data instead of making excuses?

[kgjevre]

I took another look at the pictures on http://www.isaacdirect.com and linked to them...

[EDIT] I removed the link to the picures as they have better ones on the site (see their link in post below).

I really would have liked to see the videos...
http://www.isaacdirect.com/html/Othe...FAQ.html#Video

Why don't you put the crash videos on your web site?
We were going to put the videos on the web site until a racer said, "If my wife sees that, she'll make me stop racing." Racing is supposed to be fun. Trust us, you don't want to see them.

Does it work as well in a formula car where the driver is in a very reclined position, such as the rollers sliding/rolling over the shoulders and down the chest in a crash?

Does the rollers and hardware around it cut, tear, or pinch the shoulders in a crash (not that it matters as long as one is still alive, but I am curious)?

Has the device been used in any actual and severe crashes yet where it has proved itself, and if so, does there exist any photos, video or other data from the incident(s)?

[size="1"][ July 11, 2003, 01:30 PM: Message edited by: kgjevre ][/size]

[R. Pare]

Originally posted by Gregg Baker:
You and I are on the same track. We both agree ......

Imagine that!!!

Originally posted by Gregg Baker:

First, the timing does not matter because the yield strength of any material is not a function of time.

I was referring to when it happened, not the duration. If the load was imposed AFTER the initial impact, it could be due to many variables, none of which we can speculate on with any authority, as neither of us has seen the videos or data, or know anything about the cockpit layout and how it might have contributed.

For that very reason it is in bad taste on your part to continue to insist on using the results of that sole test as a mean to promote your competing product.

Originally posted by Gregg Baker:

I see your point about the cockpit layout, but it is unlikely that Delphi can't put together a representative cockpit layout for its own tests.

You'd be surprised what can happen in even the "best" engineering firms!

The question still remains: DID they use a representative cockpit?

In response to that very question from Dave W. :
Do you know if the dummy on which the shoulder belts slipped off the HANS was supported laterally as one's body would be in a tight-fitting formula car?

You replied:

I don't know for certain. I haven't seen the Delphi setup,... but probably not.

The Wayne State University set up, as an example, is very open with no seat support above the shoulder level. The idea is to test the restraint only, with no contribution from other elements within the cockpit. In contrast, F1 tests with a cockpit mockup. One can appreciate that the F1 tests are more valid as a consequence, but belts have still slipped off (Justin Wilson).

Looks like you already answered the question about the possible invalidity of that particular test. Your citing as a sales tool the results of testing in a non-representative cockpit is akin to testing a passenger car tire in the Baja 500 and saying "Look, see? It failed!".

Your response to my observations about Justin Wilson's belt slippage:

Originally posted by Gregg Baker:
It's not a flaw in the design, it's a characteristic of the design. HANS already admitted in the above-cited e-mail that the belts came off. Since the lateral supports have been removed from the earlier design, as posted above, it's easy to picture this happening in a high-G offset frontal impact.

The "above-cited e-mail" was referring to that particular sled test, NOT Wilson's problem. One has nothing to do with the other. Wilson had NO impact with ANYTHING, so the problem he had could only be due to installation error.


You may very well have a dynamite product - I am not trying to cast doubt on that. BUT, to use the results of a single test on a product that has had a TON of successful testing in both the lab and real-world, AND use that test out-of-context as an attempt to promote your product, ranks of nothing more that shucksterism, and is in extremely bad taste.

And if your product DOES over time prove out to be as good as a HANS and someone tries to cite a single test failure as a sales tool for their competing product, I'll come to your defense also!

[Gregg Baker]

Allow me to combine some replies.

First, any comments I make regarding the HANS device relate to a very high-end performance level. Complaining about a suboptimal outcome on a 70G crash test is like whining about your 195 mph Porsche Turbo getting passed by a 215 mph MacLaren F1. What are you gonna do, swap it for a Yugo?

RP,

I'll come to your defense also!

I can't wait!

I believe that you and I are slowly coming to an agreement. (Scary thought, huh?)

We both agree that the safety of the HANS device can be sensitive to belt configuration/placement. The difference is a matter of degree. I think it is more sensitive than do you. I come to this conclusion for two reasons. First, it appears the belts came off the HANS device at Delphi on several tests, not just one (see below). Second, the F1 solution to the problem calls for using two belts, a three-inch belt below the HANS and a two-inch belt above. In total, this should strike the reasonable observer as being more than a simple matter of belt location. If the F1 solution is the way to go, I would suggest all HANS users adopt it.

Insofar as bad taste is concerned, I don't feel comfortable about being party to disseminating unfavorable information about another product. It never looks good. But if people ask me an honest question, I am going to give them an honest answer. If I have to be the bad guy here, so be it. After all, no good deed goes unpunished.

You and I may not be ready for a group hug, but we should not be at each others' throats, either. We are both "right." Of course, I'm a bit more right than you…

----------------------------------------------------------

Kristoffer,

Ouch, some of those shots are a bit old and should be replaced. We recently updated some photos on the Web site:

http://www.isaacdirect.com/html/Othe...os/Photos.html

Regarding the video, we keep it off the Web site not only because it can be shocking to the uninitiated, but because it is invariably misinterpreted by those unfamiliar with crash test protocols. For example, everyone thinks the belts are loose. Not so. They are tightened as much as possible, and the impact causes the dummy to come off the seat 6-10 inches. The list goes on. The same holds true for the data. The problem is that this is all great entertainment, but won't tell you anything about how well the product performs unless you compare it with other products, or a naked dummy.

Tell you what, send me an e-mail with your mailing address and we will ship you the video. We don’t hide our data. We would make more of it publicly available, but, as RP points out, someone can always pick some sliver of information and say, "Aha! See that! That looks goofy, so this product sucks!"

Does it work as well in a formula car where the driver is in a very reclined position, such as the rollers sliding/rolling over the shoulders and down the chest in a crash?

The rollers can't slide over the shoulders. You will see this on the video. By the time the rollers get to the shoulders, there are several tons of load on the belts. There is no way the rollers can overcome that much force.

Does the rollers and hardware around it cut, tear, or pinch the shoulders in a crash (not that it matters as long as one is still alive, but I am curious)?

We were curious about that also. The dummy has a synthetic skin. There was no evidence of any injury.

Has the device been used in any actual and severe crashes yet where it has proved itself, and if so, does there exist any photos, video or other data from the incident(s)?

Yes. Crashes have been reported to us where the driver provided image documentation. These were amateur racers, so their cars were not equipped with crash data recorders. At the extremes, one was a topsy-turvy type crash (low impact) recorded on video, the other a head-on impact (still videos) great enough to bend the seat. Send me an e-mail and I can put you in touch with the driver(s).

---------------------------------------------------------------

Kristoffer/All Re confidence in my position,

(If you are squeamish, now is a good time to leave)

This is when I should note that these are my personal opinions, and do not necessarily reflect company policy. I know that Internet postings are technically considered a public forum. So be it, but we all know that viewers constitute a small group of individuals interested in a specific topic, so I'm going to treat this as though I were with a group of racer who ask, "Wazzup?"

We have none of the data garnered at the Delphi tests in December, so we can't prove or disprove anything. If I am ultimately proven wrong, I hereby apologize in advance.

The following sequence of events lead me personally to have a high level of confidence in everything I have offered here:

1. We were contacted by NASCAR shortly after PRI to participate in the Delphi tests. For various reasons, we were unable to attend the tests. My understanding is that several devices were tested, said tests being observed by multiple researchers whose work is well established in this field. Let's just say there was a room full of Ph.Ds.

2. After the tests, someone posted on a forum (not this one) a comment that the belts came off the HANS device during the Delphi tests. This was not a smart thing to do because the information had to have been leaked by someone who signed a non disclosure agreement (NDA), who could be traced through this individual. I found this interesting but never mentioned it publicly or privately because, as we all know, any yahoo can say anything on the Internet.

3. An apparent witness to the testing then did something that was absolutely brilliant, albeit unethical: they signed up with a foreign e-mail service using a bogus name and sent us an anonymous e-mail. It was obvious that this individual had observed the tests. Their report was extremely detailed, including names, dates, places, products and test results. No mention was made of the layout of the cockpit, or lack thereof. I didn't really learn anything because most of the load data they provided was consistent with what one would predict. They did say, however (and I'm paraphrasing), "The belts came off the HANS and the dummy died. NASCAR s___ a brick. The HANS folks refit the belts several times with the same results. They even kept testing after some people had left." Obviously, this individual sent this information to us hoping we would blab. We did not.

4. People has been asking (paraphrasing again), "It is true about the HANS belts at Delphi?"

5. NASCAR recently announced it will be reviewing its H&N restraint policy, with plans to introduce new specifications by year-end for implementation for the '04 season. That told me everything I needed to know.

Do I know for a fact that this occurred? No. Do I have a high level of confidence? Yes. Too many parts and pieces fit together to make something that walks and quacks like a duck.

[Ken Adams]

+++ Response to a message from Kristoffer Gjevre

Dear racers,

In the message below, Kristoffer Gjevre describes results of testing that was conducted in late 2002 at Delphi Automotive near Dayton, Ohio, for NASCAR, and sponsored by GM Motorsports. All makers of head and neck restraints who wanted NASCAR to consider use of their restraint devices were invited to participate.

These tests were run to simulate a right front crash of a NASCAR driver who was wearing a HANS. The measured chassis acceleration in the real crash was approximately 70G, the HANS functioned well, the shoulder harness stayed on the HANS, and the driver had no significant injuries in this very severe crash.

In the initial test of the series at Delphi, the left shoulder belt came off the HANS as the dummy moved toward the right front. This was an unexpected results since the HANS functioned as expected in the real crash, which was being simulated.

It is known from many other dummy tests with HANS that the dummy is not very human-like in the area of the neck and shoulder where the shoulder belts and HANS contact the dummy. The shape of the dummy chest near the shoulders is more prominent than people and the dummy shoulders do not compress like the human collar bones to allow the arms to wrap around the belts and HANS. These shape and compressibility differences make the belts more likely to move outward on the dummy. Also, the dummy rebounds with more energy than humans so that the dummy tends to move away from the belts on rebound contributing to the belts moving laterally.

Even with these problems, the injury prediction measures (neck loads, etc.) with the HANS in this first test indicated that injury would not be likely with HANS in this severe crash. Also, these injury predictors were substantially below those measured with all other head and neck restraints that were tested in this series.

In examination of the high speed videos after the initial test with HANS, it was noticed that the shoulder belt mounts were to the right of the center line of the top of the seat and dummy neck. Also, the lap belt buckle was to the right of the centerline of the pelvis. These misalignments of the shoulder belts probably contributed to the slippage of the left shoulder off the HANS. As soon as it was detected, this misalignment was corrected by remounting center of the shoulder harness mounts toward the left behind the center of the dummy neck and paying closer attention to the lap belt buckle position.

After the other head and neck restraints were tested, a baseline test was run. In this test, the neck loads were substantially above the injury thresholds and during rebound the left shoulder harness moved to the left slipping off the dummy chest.

Because the initial HANS test did not successfully simulate the real crash where the belts stayed on the HANS and the driver, a second HANS test was run. In this second HANS test, the shoulder belts stayed on the HANS as the dummy moved toward the right front and injury measures were better than the first HANS test. As the dummy rebounded, the left shoulder moved to slip off the left side of the dummy chest and HANS essentially as it had in the baseline test.

These tests were supervised by Steve Peterson, NASCAR Winston Cup Technical Director, Tom Gideon, GM Motorsport safety program manager, Hubert Gramling, DaimlerChrysler and FIA motor sport safety expert, and Dr. John Melvin, motor sport safety researcher and advisor to NASCAR, IRL, CART, FIA, and SCCA. They all agreed that the testing at Delphi clearly supported that conclusion that HANS effectively reduced the risk on injury in the 70G right front impacts conditions tested in this series at Delphi. With all other head neck restraints tested in that series severe injury was likely.

Hubbard Downing Inc. has not released their data from this series of tests at Delphi, nor to our knowledge have any other makers of head and neck restraint that were tested in that series. There are several other tests that have been conducted with HANS and other devices that have not been released. The first technical paper that provides HANS testing data was peer reviewed and published by the Society of Automotive Engineers (SAE) in 1990. There have been a total of six peer-reviewed SAE papers that provide test data with HANS. The only data that has been published for other head and neck restraints were in a paper by Dr. John Melvin and his coworkers for the 2002 SAE Motorsport Conference. Their conclusion was that the HANS is the only head and neck restraint that substantially reduces head motions and neck loads that lead to racer injury and death.

While there have been occasional problems with belts not staying on HANS devices during racing, these problems invariably have been due to inappropriate belt mounting, which has been rectified by proper belt mounting according to our guidelines. Inappropriate shoulder belt mounting can reduce belt performance even without HANS. We are aware of no cases in which the belts have come off a HANS and there was driver injury that might have been reduced by HANS in any real racing crash.

If you've read this far, you will know that the concerns expressed below are based on misrepresentations of the testing at Delphi and other labs.

Dr. Bob Hubbard
HANS inventor

[R. Pare]

Finally, someone with some real expertise who knows what the hell he's talking about.......

And the plot gets thicker.....

[Roux]

Wow! I must admit I am one dimensional. I come straight to FF1600.com when I get on the internet. Once in a while I wonder whether I am missing out on some significant stuff elsewhere on the internet. I guess I will never find out. You guys who contribute to this site make it absolutely invaluable! I will be using my HANS for the second weekend this coming weekend and I must say that I had the same experience as one of the previous contibutors. The device spread the loads on my shoulders and collar bones in a way that made me more comfortable with very tight belts. The restriction in head rotation was never an issue and I will not be seen at speed without the device in place. I see no downside to a clubracer like myself in using HANS

Thanks again to all the experts!!!

Steve

[kgjevre]

I would like to thank Dr. Bob Hubbard & Ken Adams @ Hubbard/Downing for replying to my message and for posting a reply in this thread.

BTW, there are some interesting info and some eye-opening pictures in the 4MB document at http://www.hansdevice.com/hans-development.doc

[Stu Pidd]

Mr. Baker,

You have been exposed, HANS don't race without it !

Mr. Pare was correct, hucksterism, plasin & simple.

[Gregg Baker]

Originally posted by R. Pare:
Finally, someone with some real expertise who knows what the hell he's talking about.......

Amen to that, RP.

And the plot gets thicker.....

It will be most enlightening when Bob and I combine our collective research and design experience in biomechanics.

It's late on a Friday. More later.

[Daryl DeArman]

I'm interested in what the letter doesn't say.

..these injury predictors were substantially below those measured with all other head and neck restraints that were tested in this series(emphasis mine)...

...this misalignment was corrected by remounting center of the shoulder harness mounts toward the left behind the center of the dummy neck and paying closer attention to the lap belt buckle position...

...HANS effectively reduced the risk on injury in the 70G right front impacts conditions tested in this series at Delphi. With all other head neck restraints tested in that series(again emphasis mine) severe injury was likely..

...The only data that has been published for other head and neck restraints were in a paper by Dr. John Melvin and his coworkers for the 2002 SAE Motorsport Conference. Their conclusion was that the HANS is the only head and neck restraint that substantially reduces head motions and neck loads that lead to racer injury and death.[/QB]

My questions:

1) Gregg Baker: For clarification, did ISAAC participate in the Delphi test?

2) How far to the left were the harnesses repositioned?

3) Where was the lap belt buckle moved to?

4) How would the repositioning of the items in Q2 and Q3 affect a impact to LF? (as a road racer I am concerned with impacts in both directions)

5) Has anyone purchased the SAE papers in question? Apparently they can't be viewed without being purchased.

6) Another question for Gregg Baker: If the SAE papers from the test at Wayne State Univeristy do conclude that the HANS is the only device to substantially reduce head motion and neck loads why would your site mention the SAE papers?

7) Last question for Gregg: May I infer that there is a joint development between HANS/ISAAC in the works? Combining the advantages of both systems to make a clearly superior product. If that's done, what the heck are we going to argue about? And whose credibility are we going to attack?

[Daryl DeArman]

Two more questions, if I may?

...These tests were supervised by Steve Peterson, NASCAR Winston Cup Technical Director, Tom Gideon, GM Motorsport safety program manager, Hubert Gramling, DaimlerChrysler and FIA motor sport safety expert, and Dr. John Melvin, motor sport safety researcher and advisor to NASCAR, IRL, CART, FIA, and SCCA...

What other systems were tested?

Did those/that manufacturer(s) have representatives in attendance?

[size="1"][ July 12, 2003, 11:19 PM: Message edited by: Quickshoe ][/size]

[Daryl DeArman]

Originally posted by PRS56:
Here's what Ken Adams from Hubbard Downing has to say. I quote:

Delphi test

"The test that you speak of where the belts slipped off the device was a 100G impact."

See Below

[Daryl DeArman]

Originally posted by Ken Adams:
The measured chassis acceleration in the real crash was approximately 70G, the HANS functioned well.

In the initial test of the series at Delphi, the left shoulder belt came off the HANS as the dummy moved toward the right front. This was an unexpected results since the HANS functioned as expected in the real crash, which was being simulated.

Do I understand correctly, or were you misquoted?

First quote says they came off at 100G

2nd quote says real crash 70G and they stayed on

3rd quote refers to the simulated real crash where they came off.

Was the simulation of the real crash performed at 100G's or 70G's? I thought that perhaps the 70G's in the real crash was the force measured on the dummy and not the chassis. I am confused, please clarify my interpretations of the quotes.

Thank you

[Gregg Baker]

Dr. Hubbard,

Thank you for your reply, but it is not going to be good enough for this crowd. They are demanding real data and facts. I, however, appreciate your summary observations and opinions, even if they are unsupported.

While your comments are technically correct, your reply leaves the reader with the impression that the HANS device is superior to any other product on the market, but only because it excludes Isaac test data. That oversight is not going to sit well with this group. Rather than examining only that subset of data which might cast your product in the best light, I suggest you acknowledge the entire universe of comparative testing.

While correct in noting that the belts slipped off the HANS device during the Delphi tests, our sources erred in assuming that this necessarily resulted in fatal head loads. Absent other evidence, this was a reasonable conclusion. I will accept your observation that the loads were, to paraphrase, not fatal in the second test, but were close to fatal limits in the first. I stand corrected.

I would like to clear up a minor technical point, offer some additional insight into the Delphi tests, expand on the relative performance of the Isaac and HANS products, and pose some questions, in that order.

Two contributors from HANS have supplied conflicting information regarding the Delphi tests. You claim the impact was 70Gs. Mr. Adams claims the impact was 100Gs. I will assume 70Gs.

You said,

Hubbard Downing Inc. has not released their data from this series of tests at Delphi, nor to our knowledge have any other makers of head and neck restraint that were tested in that series.

Please be aware that HANS competitors who tested at Delphi have published specific test results indicating that their product also produced non-fatal head loads. See the current G-Force catalog. Without specific HANS data, one cannot conclude that the HANS device is superior to others tested at Delphi.

You said,

The only data that has been published for other head and neck restraints were in a paper by Dr. John Melvin and his coworkers for the 2002 SAE Motorsport Conference.

This is not true. You and Jim Downing were sitting in the front row of the audience observing the presentation of the peer-reviewed SAE paper #2002-01-3306, which dealt with the development and test performance of the Isaac system. When one combines the results of this paper with the one you cite (Dr. Melvin’s peer-reviewed SAE paper #2002-01-3304), one has the only side-by-side tests comparing the Isaac system, the HANS device, the Hutchens device and the D-cell--same crash dummy, same crash sled and same crash pulse.

The HANS device did outperform the Hutchens and D-Cel products, but the Isaac system slightly outperformed the HANS. Let’s just say they were equal as the differences were small.

So what do we know to be true?

1. The HANS device outperforms the Hutchens and D-Cel products. It performs almost as well as the Isaac system, but the differences are technically trivial so let us give the HANS the benefit of the doubt and say it performs as well as the Isaac system.

2. The belts slipped off the HANS device at the Delphi tests. This can be attributed to the fact that a crash dummy is not an exact duplicate of the human body.

3. The resulting HANS loads at Delphi were non-fatal. You present no data to support this conclusion, but I will accept it. Others may not.

4. HANS competitors who also tested at Delphi have published specific load data indicating non-fatal results. Without test data, it cannot be demonstrated that the HANS device is superior to other products tested at Delphi.

Without disclosing information you may wish to keep secret, any responses you care to provide to the following questions would be helpful:

1. At Delphi, what were the F-sub-z, Head G and HIC values for your product?

2. Did the lateral component of the impact vector generate an M-sub-x moment of any consequence?

3. Were additional tests, beyond those you mentioned, also conducted on the HANS device? If so, what were the results?

4. How long were the tethers/straps on the test HANS device(s)?

5. Given that the F1 belt-slippage problem has been addressed with a dual (upper and lower) belt configuration, are you recommending that all HANS users employ such a configuration?

Thank you for your contributions. We look forward to your reply.

Gregg S. Baker, P.E.
Isaac inventor

[KenAdams]

There was also a 100G HANS test performed. The dummy survived, but the belt did slide off one side of the HANS on rebound. This was due to the reasons cited by Dr. Hubbard above (dummy chest shape), as well as the shoulder belt adjusters releasing slack under the 100G load.

Sorry about the confusion.

The Isaac was not included in the 70G or 100G tests.

We are here to eliminate incorrect information, not to validate our product. Our customers, and independant technical experts do that for us.

We feel that we are very open with the performance data that we have aquired over the past 10 years of testing. A great deal of information is available at

http://www.hansdevice.com/hans-development.htm

If anyone has any specific inquires, please direct them to:

info@hansdevice.com

Or feel free to call us,

770-457-1046

We appreciate the opportunity to help clear things up here...

Regards,
Ken Adams
Director, HDI

[Gregg Baker]

Originally posted by Quickshoe:
1) Gregg Baker: For clarification, did ISAAC participate in the Delphi test?

Apparently not, according to Mr. Adams.

5) Has anyone purchased the SAE papers in question? Apparently they can't be viewed without being purchased.

6) Another question for Gregg Baker: If the SAE papers from the test at Wayne State Univeristy do conclude that the HANS is the only device to substantially reduce head motion and neck loads why would your site mention the SAE papers?

Copyrights are assigned to the SAE when they agree to publish a paper. They get some funding from sales to support their programs, and offer a venue for publication. Pretty good deal for all involved. If you are a member, you can download the PDFs for about $10 each.

We included the reference to both papers so racers could compare the products in the same crash environment.

[Gregg Baker]

Originally posted by KenAdams:
There was also a 100G HANS test performed. The dummy survived, but the belt did slide off one side of the HANS on rebound. This was due to the reasons cited by Dr. Hubbard above (dummy chest shape), as well as the shoulder belt adjusters releasing slack under the 100G load....

Thank you for the clarification.

If anyone has any specific inquires, please direct them to:...

We would all benefit if any questions racers have are asked and answered here, in public.

We appreciate the opportunity to help clear things up here...

As do we.

[John Robinson]

Gregg,
I'll place my head on the chopping block, please make it one quick swing, dont drag it out. If I was looking to purchase a restraint system, I would get a HANS. Basic reason being, I can look at the unit and visualize how it helps. With the ISSAC system I see moving parts and opportunity for problems. I am also concerned about the angle of the shocks (remember I mentioned earlier I am not an engineer). The HANS will only allow my head to travel a limited distance forward from my shoulders, while the ISSAC first needs the rollers to contact my shoulders.

Please remember I am saying this as John Q Racer, not an analytical engineer, so the raw test data, unless you explained it to me in basic terms would not be real helpful.

I am just trying to be honest. I feel that the ISSAC system is better then the other products that are offered, I am just not sure it is as good as the HANS.

I know the belts could be an issue with the HANS, but wouldnt you want them set up correctly no matter what system you are using?

PLease continue the work you are doing as it could result in a better product for all.

John Robinson

[Gregg Baker]

Originally posted by John Robinson
Gregg,

I'll place my head on the chopping block, please make it one quick swing, dont drag it out.

Geez John, you make me sound ill tempered. I'll concede to being overly enthusiastic on occasion, but it is always with the best intentions.

If I was looking to purchase a restraint system, I would get a HANS.

If getting you in a head and neck restraint means you selecting a HANS device over an Isaac, please buy the HANS.

Basic reason being, I can look at the unit and visualize how it helps. With the ISSAC system I see moving parts and opportunity for problems.

It is not intuitively obvious how Isaac works. It looks a bit odd, and unless one knows that shocks become more rigid with velocity, one does not have that palm-slapping-the-forehead, "Now-I-get-it!" kind of experience.

I am also concerned about the angle of the shocks (remember I mentioned earlier I am not an engineer).

The shock angle does generate some compressive loads, but all products--and a naked head--will generate some compressive loads in a crash event. We spent more time on this than any other element of the design. If the shocks are too stiff the compressive loads are too high; if too loose the tensile loads are too high.

The HANS will only allow my head to travel a limited distance forward from my shoulders, while the ISSAC first needs the rollers to contact my shoulders.

Not really. I know it looks that way, but the mass and friction of the belt connectors cause them to lag behind the head in the early portion of the crash event, so they rapidly adopt a more horizontal attitude. The shocks begin to work long before contact is made with the shoulders.

Please remember I am saying this as John Q Racer, not an analytical engineer, so the raw test data, unless you explained it to me in basic terms would not be real helpful.

We get some of the best ideas from John Q Racers. You are right about the data. Unless you have been versed in what you are looking at, it's just a mountain of numbers.

I am just trying to be honest. I feel that the ISSAC system is better then the other products that are offered, I am just not sure it is as good as the HANS.

It is as safe as the HANS, according to established crash test protocol. Could someone eventually discover a safety advantage HANS has over Isaac? Of course, but the opposite could also be true.

I don't want to spill any beans, nor claim anything unproved, but our computer simulations for pure lateral impacts look promising, for example. People continually talk about frontal, or near-frontal impact. Personally, I find this boring. Researchers have been conducting frontal crash tests for decades, and nearly everything that can be learned has been learned. I would prefer resources go toward the studies of lateral, vertical and rotational impacts, since many crashes involve a combination of these loads.

I know the belts could be an issue with the HANS, but wouldnt you want them set up correctly no matter what system you are using?

I agree completely. All belts should be installed according to the manufacturer's instructions. Ideally, they would not have to be relocated to accommodate a head restraint.

Please continue the work you are doing as it could result in a better product for all

John Robinson

We understand the appeal of the HANS device. It works very well and racers are familiar with it. Our marketing challenge lies not with the product, but with the fact that it is relatively unknown and uses a fresh technology. A friend of mine, a marketer, said (I'm paraphrasing), "Be patient. At least you guys haven't invented the light bulb. Can you imagine telling life-long kerosene lamp users that they don't need fuel, don't need a match, and that you are going to light their homes by forcing dangerous electrical current through a wire? Yeah, like they're gonna buy that thing."

Okay, so we're not that good. Nevertheless, I like the analogy.

John, when you get serious about a head and neck restraint (please make it soon), we'll get you an Isaac rental package at no charge.

[size="1"][ July 15, 2003, 07:06 PM: Message edited by: Gregg Baker ][/size]

[John Robinson]

Gregg,
Another question for you, you mentioned that the shocks start working before they touch the shoulders. That means to me that the drag of them on the belts starts the damping process. you then state that the angle becomes more horizontal, this to me would mean that either the belts raise up or the helmet has to come down. If the helmet moves down, wouldnt that add to compression of the neck?

FWIW, I already purchased a HANS unit. I did so before I knew about the ISSAC system. Unfortunately I can not use it in my CF due to belt spacing. The car will have to be stripped to the frame in order to relocate the mounting points. It will work fine in the swift tho.

Will you be at the double SARRC at Daytona? I wouldnt mind trying one of your helmets for fit, but I dont think I want to try it out totally. Damn sure dont need to hit the wall there...lol. Savannah was bad enough.

John

[Gregg Baker]

Originally posted by John Robinson:
Gregg,
Another question for you, you mentioned that the shocks start working before they touch the shoulders. That means to me that the drag of them on the belts starts the damping process. you then state that the angle becomes more horizontal, this to me would mean that either the belts raise up or the helmet has to come down. If the helmet moves down, wouldnt that add to compression of the neck?

John,

There is an addition to normal compression, yes. The net result is that both the Isaac and HANS produce about 200# compression and tension in a 45G impact, although they do it in a different manner.

FWIW, I already purchased a HANS unit. I did so before I knew about the ISSAC system. Unfortunately I can not use it in my CF due to belt spacing. The car will have to be stripped to the frame in order to relocate the mounting points. It will work fine in the swift tho.

Will you be at the double SARRC at Daytona? I wouldnt mind trying one of your helmets for fit, but I dont think I want to try it out totally. Damn sure dont need to hit the wall there...lol. Savannah was bad enough.

John

There won't be an official company presence at the double, but the wife and I typically spend weekends at a beach house near Daytona, and I always stop by they track whenever something is racing. Sure, you can use an Isaac. I'll even bring along the all the crash data/video on the laptop.

Yeah, don't break anything!

[Gregg Baker]

Originally posted by John Robinson:
Gregg,

...FWIW, I already purchased a HANS unit. I did so before I knew about the ISSAC system. Unfortunately I can not use it in my CF due to belt spacing. The car will have to be stripped to the frame in order to relocate the mounting points...

John

John,

You are not alone. Hubbard/Downing, Inc., the manufacturer of the HANS device, sent a letter to chassis builders regarding specific belt-mounting criteria.

To our knowledge, this letter was not sent to sanctioning bodies, so racers should not rely on their organizations to ensure that their belts will adequately accommodate the HANS device.