Head and Neck Restraint Options?

[Daryl DeArman]

Some of you Isaac "salesmen" scare me, your disregard for your own safety is scary. Why would you take a chance with your life? Can't you see that you're reducing your chances of a neck injury at the expense of increasing your chances of burning to death? We are debating the merits of a safety device and turning a blind eye to another important safety concern.

Well, Mr. Treat.

Have you ever tried an ISAAC? I'd be concerned racing with anyone that didn't possess the simple skills required to release the device in less than 2 seconds. I can get out of my FVee with my ISAAC on and my eyes closed faster than anyone can get out of their tin top with a HANS device on, and that is assuming their HANS doesn't get hung up on anything on the way out!! Probably faster than 99% of all HANS device users can get out if they have a drink tube or radio, much less both. By your logic should we disallow the use of the HANS in tin-tops? Window nets and/or arm restraints slow our egress but aren't they there for a greater good? It is classic Risk vs. Reward. To assume that us ISAAC "salesmen" have sold ourselves short is ludicrous. I'd suggest that those ISAAC users have done more research and given it more thought than the users of other devices.

I believe that the degree to which I increase my odds of burning to death with an ISAAC vs. HANS is proportional to the extra protection in an impact I am awarded by wearing an ISAAC over the HANS. (as long as we are talking about open cockpit cars I feel there is minimal difference in both situations, in a tin top the egress difference is HUGE) To me, it is almost an even trade, but then I take it another step...I feel the chance of me being involved in a severe impact is GREATER than that of me being in a fire. Fire is a bigger fear of mine than anything else, another reason I chose the ISAAC. That is why I wear Carbon-X full length underwear, socks and balaclava, 3 layer OMP suit, 2 layer nomex gloves even if it is 110 degrees in August at Buttonwillow. I also practice getting out of my car with my eyes closed everytime...simulating hitting the fire nozzle as well.


In closing, I would argue that many of you HANS users have sold yourself short by following the herd. Why do you choose to take such chances?

[Stu Pidd]

"In closing, I would argue that many of you HANS users have sold yourself short by following the herd. Why do you choose to take such chances?"

The 'herd' I'm following includes Schumacher, Montoya, Alonso, Tracy, Junqueira, Bourdais, Kannan, Hornish, Harvick, Waltrip etc.

Who is in your 'herd'? Anyone I might have 'herd' of? (with apologies to Eyerace)

[T.A. Treat]

Wow! I didn't even name names and you guys got defensive.

I will admit to being overly sensitive to fire. Maybe it's because I've witnessed race cars on fire or maybe it's because my brother is a fireman. Yes, I checked my fuel cell last winter and added rubber strips to protect it from chafing. I wear a three layer suit and nomex underwear (exceed the GCR standard).

Think about the much publicized crash with Dale Jr at Infineon. He was out for a minute or so. The corner worker that pulled him out of that flaming Corvette may not have been successful trying to find the two pins. It's just not a chance that I would take. Those of you that keep stating that you can get out of your car fast, I still can't see why you would intentionally add two steps to the process.

I've told you I don't care what anyone else chooses. My main beef with the Isaac company is the fact that they are knowingly promoting and selling a product to SCCA members. If the GCR is changed to allow the Isaacs system, then my gripe is over.

[Gregg Baker]

Without going through comments point-by-point, let's review a couple of things:

1) As I reread my previous post I saw how it could be interpreted as heavy on the chearleading. I should have anticipated that and chosen my words more carefully. The intent, however, was to emphasize a very important safety point, namely...

2) Having to drag your head and neck restraint out the window is extremely dangerous. This is not debatable. It's not my opinion. It's not a marketing pitch. It's reality, like gravity, and the record proves it. The HANS device has repeatedly trapped drivers in burning cars. People have this backwards.

Granted, open-cockpit drivers are at much less risk, but you guys are in the minority. 80% of racers are either drag or oval and the vast majority are in closed cars, as are most road racers.

3) The Isaac system is not "illegal" in SCCA. The comments in the August '04 Fastrack were not incorporated into the 2005 GCR, the April '05 Fastrack makes reference to "not recommended", and no driver will be denied their Isaac system. It is a case of the 40 year-old paperwork catching up to modern science.

4) Stu Pidd, don't be stupid. Those guys are forced to use that product.

[Gregg Baker]

My main beef with the Isaac company is the fact that they are knowingly promoting and selling a product to SCCA members.

Every racing vendor knowing promotes and sells its product to SCCA members.

If the GCR is changed to allow the Isaacs system, then my gripe is over.

There is nothing in the GCR that disallows any H&N restraint product.

Oh, never mind.

[Daryl DeArman]

Mr. Treat,

You really didn't need to name names. I am one of the vocal supporters. I have no problem with someone choosing to use another device. I took exception when you suggested, basically, that I made a 'Stu Pidd' choice.

I see your beef...In theory perhaps the letter of the rule is an issue. In practice it doesn't seem to be a problem. Many SCCA racers use the ISAAC and will continue to do so.

I have less points to release than the HANS user with a drink tube and radio lead and I have less chance of having my device get hung up on something as I exit the vehicle (it stays in the vehicle). I have to worry less about the angle of impact, belt spacing, proper tether length, and that I chose the proper model for my seating position.

[Daryl DeArman]

Stu Pidd,

Of those professionals you mentioned, what other options do they have? How many of them would wear something else given the choice?

If you wish to look at what professionals are wearing to guide your decision making process, I believe you will find that medical professionals, engineers and physicists who race make up a higher percentage of ISAAC's clientele than other devices.

[Greg Mercurio]

Needed to come out of my cave for a bit of fresh air, so I thought I'd drag this tidbit with me from Fastrak.


April '05 Fast Track
Items Not Approved - GCR
"3. Allow the Isaac device (Loesch). The CRB addressed this last year and found that the device does not comply with the GCR section 20.4 (single release). Further, there now exists FIA and SFI specifications for head and neck restraints. Major sanctioning bodies including the SCCA are considering adopting the specifications, and both preclude the use of the Isaac."


For those of you that don't know, Fastrak is the living document that accompanies the GCR. It modifies the GCR each month as well as a few other functions. The above is not ambiguous in any way. It clearly states that the ISAAC is NON-COMPLIANT to GCR 20.4 and as such, no GCR changes were made to make it "legal" to use. Spin it any way you want, but like the preacher in Blazing Saddles said to the Sherrif "Yer on yer own."


When Michael Cantu pulled Jr. from the car he toasted, he probably didn't stop to ask himself if he needed to look for the extra restraints. He ran towards a fire, reached into a burning car, found the harness release and dragged the driver out. How do I know this? Because Michael and I are friends, and we share a meal regularly at the track.


Now, consider this:
1) Michael has been around race cars his entire life.
2) Michael is a BIG guy.
3) Michael is a flagger, and is NOT WEARING NOMEX.
4) Michael just happens to be licensed as an emergency crew as well.
5) Michael is NOT WEARING NOMEX.

Do YOU want to be the driver that takes yourself out and a perhaps sends a volunteer to the burn ward because YOU are using a device that required additional releases? Whether or not you can release yourself in a half second or a millisecond is not at issue. It's about getting you out of the car when YOU CAN'T get yourself out.

This whole issue has been and continues to be about whether or not the ISAAC meets the requirements of the GCR. It has NOT been about whether it works. The energy spent defending and seeking relief from the rules is amazing. Why not pool that energy and redesign the ISAAC to make it conform and the battle stops.

Maybe I'll design and market Titanium-Unobtainium wheels and promote them here. Why not? They not compliant, but they're safer than cast aluminum.

Ok, ok, back to my cave of ignorance.

[Daryl DeArman]

Whether or not you can release yourself in a half second or a millisecond is not at issue. It's about getting you out of the car when YOU CAN'T get yourself out.

Agreed that is a huge concern. That is why when I first started wearing my ISAAC I attended the safety/flag gatherings in the morning to show them the device and make certain they were familiar with it. One who wasn't said that his sharp knife would slow him down a nano-second. Same type of knife would have been used had Jr. got hung up on his window net, drink tube, radio lead, fresh air vents or anything else.

This whole issue has been and continues to be about whether or not the ISAAC meets the requirements of the GCR. I has NOT been about whether it works.

I disagree, the topic was started by someone wanting to know what his options were.

How many ISAAC users have you told they can't go out on the track? How many people with modified helmets have you told that they have voided their snell certification and their helmet is non-compliant? Or were you informed in a FASTRACK that determining the legality of a helmet is outside your area of knowledge and reponsibility?

[Greg Mercurio]

Wellllllllllllllllllllllllllllllllllllllllllllllll lllllllll......

1) I have not told any user that they could not go out on track. However, as a licensed National Scrutineer and an ex-Chief Scrutineer, I would not apply an Annual Sticker to a helmet that was exhibiting the mount points for the device as it is non-cmpliant. Same would apply to a car that was non-compliant, or gloves that had holes or harnesses that were frayed and the list goes on. A licensed Scrutineer cannot willingly grant a Tech Sticker to a non-compliant car, or driver. That's like, THE POINT!

2) I have not told anyone who has modified their helmet that they voided their Snell Certification for the simple reason that they did not void their Snell Certification. That subject was covered a long time ago, to most everyone's satisfaction. That dog won't hunt.

3) I agree that most Scrutineers and Grid people are not qualified to assess the integrity of a helmet, but it is certainly within both Specialties purview to asses whether they are compliant to the GCR. Most folks in both of those Speciaties up here actually read the GCR and are smart enough to ask for help when they don't understand what's been written.

My hope is that all Scrutineers and their Chiefs are smart enough and savvy enough to base their decisions on what is in the GCR and the latest Fastrack and not on marketing claims. I know that Dennis in CalClub and Kathy up here certainly are.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>

Now..................for the non-commercial commercial. For months, the I###C Device has been plastered all over this site, and others. It actually gives this product immense marketing power as (in my limited understanding of web stuff) search engines look for keywords in postings all over the web. So every time we post using I###C, Mr. Baker get free promotional consideration. Which may be the whole point? There's certainly no power in I###C is there? Which is why I will no longer add to the free marketing account of Mr. Baker and Co.

[Charles Warner]

I disagree, the topic was started by someone wanting to know what his options were.

Not exactly correct. It was a query about the options to the HANS device for SCCA. One only has to consider the reference to F500 and check out the gent's website to determine this. As of this writing the I###C is NOT approved for use in the SCCA. Pure and simple!

Mr. Baker states that a change is in the works. This flies in the face of the latest in Fastrack. As a member of the Sports Racer/Formula Car Advisory Committee I ask him to provide a reference to this expected change.

I applaud Mr. Baker for taking the time and energy, not to mention expertise, to develop such a device. He is to be commended. HOWEVER, somehow the ball was dropped when it came to playing the game of getting it accepted by the largest amateur racing group in the U.S. Whether this is a political issue or not is moot. It ain't accepted as of now! I realize we live in the age of caveat emptor, but, to imply these devices can/may be worn at SCCA events is misleading. Regardless of how well they provide their designed protection, they are NOT approved. Regardless of how some want to denigrate the SFI standards, the I###C does not enjoy that organization's auspices. To quote Billy: more's the pity.

We need to focus on more professional behavior and comments regarding this issue. No one here can do anything about the issue. It is between Mr. Baker and the Club. Let them handle it! To question the safety motivations or mental abilities of those who choose to wear either device (or none at all) is not very gentlemanly.

[fatbillybob]

Gee...maybe Isaac does have a problem. You win a race with a non-approved device and your competators claim you have an unfair advantage because the Isaac offers such great lateral support that your neck doesn't get as tired from all the G-forces so racing now does not sap your stamina as much. Good reason to buy one. It must be worth a few tenths...

[Steve Demeter]

Enough already.
Too much venom being spewn here.
Facts are :1. The ISAAC does work. I do not think that anyone disputes that
2. Currently it is not appr3oved per the GCR.
3. Mr. Baker is not trying to slick or otherwise do anyone wrong. He is simply promoting what he, as a Registered Professional Engineer, believes to be the best device.
So lets let it go and get on with it.
If anyone wnats to change fact 2, there is a mechanism to do that.

[MarkM]

You boys can use this as a time out.

Does anyone have a link to the Jr. crash video. It was my memory that he extricated himself from the car, not pulled out by someone. I remember thinking at the time, "Where are the workers?". Correct me if I am wrong.

Mark

[Gregg Baker]

You boys can use this as a time out.

Does anyone have a link to the Jr. crash video. It was my memory that he extricated himself from the car, not pulled out by someone. I remember thinking at the time, "Where are the workers?". Correct me if I am wrong.

Mark

Time out!

Correct. Jr. bailed on his own.

[Gregg Baker]

This whole issue has been and continues to be about whether or not the ISAAC meets the requirements of the GCR. It has NOT been about whether it works. The energy spent defending and seeking relief from the rules is amazing. Why not pool that energy and redesign the ISAAC to make it conform and the battle stops.

We've already redesigned it. That part's easy. The energy you speak of is being offered because the present rules are dangerous, and we--and others--want to see them changed before someone gets hurt.

It speaks volumes that a legitimate call to change a dangerous, outdated rule is taken as a self-serving attempt to skirt the rules. If we were attempting to cook the books in our favor we would petition for a banning of competing products.

Maybe I'll design and market Titanium-Unobtainium wheels and promote them here. Why not? They not compliant, but they're safer than cast aluminum.

Agreed. If you can offer drivers a safer product you have a moral obligation to do so. Someone may keep them from buying it, but at least your conscience is clear.

[Gregg Baker]

...It actually gives this product immense marketing power as (in my limited understanding of web stuff) search engines look for keywords in postings all over the web...

We wish. A spyder is going to step right over this, Greg. Search engines look for concentrations of key words, not a few here and there.

Google "head neck restraint" or "head restraint" and see what happens. If you find a reference to a forum thread it will be buried very deep.

[Gregg Baker]

Mr. Baker states that a change is in the works. This flies in the face of the latest in Fastrack. As a member of the Sports Racer/Formula Car Advisory Committee I ask him to provide a reference to this expected change.

Charles,

I'll bet you a beer that there will be a major rewrite of the GCR safety rules.

I applaud Mr. Baker for taking the time and energy, not to mention expertise, to develop such a device. He is to be commended. HOWEVER, somehow the ball was dropped when it came to playing the game of getting it accepted by the largest amateur racing group in the U.S. Whether this is a political issue or not is moot.

As an SCCA member and long-time road racing fan it pains me to say this, but the SCCA is a back burner issue for us. 40% of the market is oval racing and another 40% is drag racing. There are 200 formal racing organizations and another 200 informal clubs in the U.S. alone, and the vast majority of them address the egress issue from the standpoint of time-to-exit--which only makes sense.

...but, to imply these devices can/may be worn at SCCA events is misleading.

Sorry Charles, but racers are not being denied the use of their Isaac systems. Topeka surely is aware that any injury resulting from denying a driver the use of a safety product would produce astronomical liability. Let's just call it a case of don't ask, don't tell.

We need to focus on more professional behavior and comments regarding this issue. No one here can do anything about the issue. It is between Mr. Baker and the Club. Let them handle it! To question the safety motivations or mental abilities of those who choose to wear either device (or none at all) is not very gentlemanly.

Here, here.

Seriously gentlemen, we already have a retrofit version in the works. We just realize it is suboptimal.

[R. Pare]

It's amusing seeing the creative interpretations going on with the GCR!

GCR 20.4 clearly states that the single release requirement pertains ONLY to the SEAT BELT AND SHOULDER HARNESS as those are SINGLED OUT as the subjects, and the ONLY subjects, of the single release requirement. NOWHERE does it state that the ENTIRE DRIVER RESTRAINT SYSTEM must be of single release. Without that caveat, 20.4 has ZERO bearing on secondary restraint releases. To think such is to not understand the English language very well.

HOWEVER, section 20.8 clearly has bearing on ALL driver restraint systems (that is the exact wording), and it requires that ALL driver restraint systems shall meet SFI 16.1. No ambiguity there at all.

THAT is the only part of the GCR that currently makes the use of the I$$$c illegal (assuming the thing doesn't have the 16.1 approval).

IF somehow the I$$ac get SFI 16.1 approval, then it is CLEARLY a legal devise.

PS : To deny an annual sticker to a helmet that has the I$$$c mounts on it will get you a sh!t fight if the helmets owner knows the GCR at all. If the extra mount does not in any way violate the terms of the Snell approval - which is the ONLY thing stated in the GCR as a requirement - then it's presence has no bearing on the legality of the helmet, period. There is no proviso in the helmet requirement that states that the Steward or Scrutineer can make up the rules as he goes along if he doesn't like the equipment!

[Greg Mercurio]

Richard, with all due respect, suggest you read paragraph 1 in section 20 GCR defining the restraint system.

Excerpted for brevity is this handy little nugget:

..."The restraint system installation is subject to approval of the Chief Technical and Safety Inspector."...

Look in GCR 6.18 That's the Chief Scrutineer.

Gives the Chief a LOT of latitude in interpreting the GCR and Fastrack.

[Rick Silver]

I wore my Hans device for all of the test sessions and race at Summit Point this past weekend. In the end, the device was comfortable and in fact I think I prefered wearing it as the belts did not seem to loosen at all as they seem to do after a few laps. The device really holds you firm in the car. I have a late model Van Diemen. I had to have my Willans belts modified and slightly alter the belt mounts to make them closer and the correct height. I also changed the padding they provided to a thinner pad which helped the fit.

I did not notice it at all while it was on. I got in and out of my car alone all week and again had no problem, as long as I went through the somewhat required step by step procedure to get in alone. But it is not that big a deal even in a rush situation. With the potential safety gains for frontal and role over crashes, I will wear it from now on.

[R. Pare]

The "little nugget" you refer to only states the the INSTALLATION of such system is subject to the Chiefs approval, NOT the system itself, nor whether or not the I$$$c mounting system has any bearing on helmet legality - if the I$$$C mounts are installed correctly, then the Chief has no valid basis for disapproval. " Lattitude" or not, the RULES AS WRITTEN still have to be followed. The Chief CAN ask that the mounts be removed, BUT cannot deny helmet approval bacause of that installation - the rules governing helmet legality do not address that.

This is just another typical case of club officials desiring a certain outcome and re-interpreting the rules to suit!

6.18 DOES NOT give the Chief "lattitude" in interpreting the GCR - it only states that it is part of his duty to enforce it!

[Daryl DeArman]

also recall: Fastrack F80 RM04-05

"SCCA technical inspectors/scrutineers and other SCCA officicals are advised that it is not within the authority or the technical ability of the SCCA or SCCA officials to determine if a helmet certification (Snell, etc.) has been voided by modifications made to a helmet that is worn by an SCCA competitor..."

[R. Pare]

I had missed that one! Thanks remembering it and pointing it out - it supports my arguement exactly!

[Rick Kirchner]

So let me see if I understand this:

The SCCA wants to encourage the use of H&N restraints
but...
Only if SFI approved
and...
The major impediment to the ISSAC device is single release
but...
In order for that to be a real safety issue I need to have:
1. a crash
2. unconsiousness
3. a fire

So this ends up being an argument over one of those "probability of A given B given C types of situations compared to the probability of unconsciousness given a crash without the use of a H&N device.

The same equation predicts aircraft crashes every few hundered thousand flights, but we still climb in a big aluminum tube and entrust our souls to the 2 million or so slightly failure prone parts assembled and tested by a lot of guys that occasionally drink too much and spend the day pissed off at their boss.

Now I wouldn't want to suggest that the club or the SFI for that matter has any real or relavant data to support one ruling or another. It's far easier to support your position through an outpouring of emotion rather than the third most significant digit.

Who knows, maybe we'll have to get our H&N systems recertified or replaced every two years, resin does deteriorate in the presence of UV and solvents.....

Scientific arguments accepted, but based on that 2 year rule every smart guy out there that sees SCCA and SFI in close proximity should have their BS light come on.

I don't think the great Satan in this debate resides at Mr Baker's address, but I can think of a couple other potential locations.

[Radicalone]

I find it hard to believe that any sanctioning body in the world would allow the I$$$c device.It may work great in frontal impacts and if all impacts were frontal the device would be ok.Unfortunately there are impacts from other directions.IMHO no sanctioning body should allow metat brackets and metal rods to be attached to ones head.When you back it in and said metal rod gets caught on something like the back of your cockpit , roll hoop ,headrest etc. there is a very good probably of getting the metal rod shoved through your head.If the sanctioning bodys are interested in the safety of their members they should ban any object that could puncture ones body from the cockpit.If I were a sanctioning body I would be worried about the legal ramifications when someone gets killed from a rod through the head from a device that they allowed.

[Daryl DeArman]

Radicalone,

The chances are extremely slim-to-none of those rods and/or brackets puncturing ones' helmet. The forces that would be required to shear one of those rods or mounts is way beyond what anyone is going to live through anyway...your inards would be jell-o. NOt only would the energy be required to compress the damper, but further shear the mount or damper and then penetrate your helmet. Do some math, see what kind of force it would take to shear a rod or mount of that size and material and then weigh your head and helmet and see what it would take acceleration wise...no worries if the math is too complicated, it isn't going to happen.

You are correct about angle of impacts though. We need to realize that most of our impacts are not going to be exactly straight-on with a perpendicular object. From what I have read the HANS is at its' best in a straight-on crash. As you deviate from that path its' effectiveness decreases rapidly. I would guess ALL devices will also lose effectiveness as that angle increases, simple physics. Finally, when you get to 90 degrees the HANS offers zero protection, the ISAAC will offer some. With this in mind, the basal skull fractures are probably not as likely the further you deviate from a straight axis to a side impact. However, it would be nice to be protected from injury as well as death. So the head and neck restraint people need to design for a combination of the most fatal type of incident weighed against the most common. As drivers, we need to also make certain that we have some type of protection for the head in a side impact. Sedans need nets and/or extensions of the side of the seats' head rest. We need to have good cockpit surrounds near our heads and good quality padding around roll bars.

If you really want your sanctioning body to outlaw anything in the cockpit that might harm you in an accident...take a good look around your cockpit next time you are in there. A steering wheel and shaft to/through the sternum probably doesn't feel too good. We ought to outlaw the helmet chin straps too, because they might crush someone's larynx in a rearward impact someday. Oh yeah, and those pesky roll bars and such might kill someone someday by breaking their helmet and their skull, or a side impact bar protrude through your neck in a good impact...point is chances are VERY SLIM and the devices there for a greater good. They used to think seat belts were bad and you are better off being "throwed clear"

safe racing,

Daryl DeArman

[Charles Warner]

Radicalone,

Do some math, see what kind of force it would take to shear a rod or mount of that size and material and then weigh your head and helmet and see what it would take acceleration wise...no worries if the math is too complicated, it isn't going to happen.

Daryl DeArman

For those of us too stupid to do this complicated math why don't you enlighten us and provide these computations?

[Gregg Baker]

For those of us too stupid to do this complicated math why don't you enlighten us and provide these computations?

Gladly.

Sigma (unit stress)=P/A, or Force/Area

Force=Mass x Acceleration

Mass= head mass + helmet mass
Head mass = 8-12# for an adult male (depending on where you place the band saw on the cadaver’s neck)
Helmet mass = 2-4#
Mass=call it 15# to be conservative.

Acceleration is a variable, but let’s use 100Gs for a really big hit.

Substituting,

F=ma
F=15 * 100
F=1,500#

We now know the force to be 1,500#. In order to determine the unit stress, Sigma, we need to calculate the area to which this shear force is applied. Given two rods we know the total area to be,

2*pi*r^2,

where r is the radius, in this case 3mm, or 0.118” to keep everything in English units.

Substituting,

A=2*pi*0.118^2
A=0.088 square inches

Therefore, the unit stress of a 15# head-helmet combination subjected to a 100G acceleration acting in single shear on an area of 0.088 square inches is,

Sigma=P/A
Sigma=1,500/0.088
Sigma=17,045 pounds per square inch.

To determine the safety factor (typically noted as K sub s, which we cannot do in this format) this unit stress is divided into the shear strength of the material. Although the manufacturer considers this information to be proprietary , one can reasonably assume either a cold-worked mild steel, or a mid-grade stainless steel, either of which will exhibit a yield strength in the neighborhood of 70,000 psi. For most ferrous metals the shear strength is known to be approximately half the yield strength, in this case 35,000 psi. Hence, the safety factor is,

Ks=35,000/17,045
Ks=2.053

So, a driver with a 15# head-helmet combination subjected to a 100G side/rear impact which must be absorbed completely by the damper rods acting in shear has a 2:1 cushion.

In other words, for the impact scenario offered, the I$AAC system should theoretically protect the driver to an impact of approximately 200Gs, a level at which your heart will tear away from your aorta, as noted above.

QED

Damn, we should have done this years ago.

[Charles Warner]

Gregg,

Thanks for the computations (QEF by Quickshoe?) but I would like to ask an associated question.

What shear strength do you attribute to the helmet mounting system and the associated helmet structure? You assume the helmet shell and mounting system will be able to take the 1500# impact shock? Do you assume the shock to the helmet mounts will be evenly divided between the two sides?

Obviously the rods are strong enough to withstand more loadings than we will ever reasonably be able to exert in normal operation. However, if the driver's head happened to be turned full left, to see where he was headed (I understand he has reasonably free movement as long as the movement is made normally?), and then the car had a severe (100g) direct rear impact, would not the limiting factor be the integrity of the helmet structure and its ability to withstand the intrusion load of the rod being pushed through the helmet?

Please do not get me wrong. I have no problems with the device. Yours simply does things differently than the HANS. Two things I appreciate about the HANS are (1) that it only limits the head movement in a narrow range, & (2) it provides a form of headrest or rearward support. I just had an accident similar to the situation I described above. The HANS device limited my ability to turn my head to the left (even though I wanted to) and also provided something of a cushion between my helmet and the car's structure on impact. The impact was about a 60 degree glancing blow and the HANS then limited my head's rotation to the right. The impact was hard enough that I destroyed a Bell Dominator.

[Daryl DeArman]

QED/QEF???

Enlighten me, I'm not stupidd, just ignorant. I'd like to be in on the joke, if it was one.

[Charles Warner]

QED/QEF???

Enlighten me, I'm not stupidd, just ignorant. I'd like to be in on the joke, if it was one.

QED (or Q.E.D.) quod erat demonstrandum (L)

"which was to be demonstrated"

QEF (Q.E.F.) quod erat faciendum (L)

"which was to have been done"

[Daryl DeArman]

Thanks for the latin lesson. Learn something new everyday. I thought it might have been some forum slang poking fun at me, and I was missing (or was) the joke.

[Gregg Baker]

What shear strength do you attribute to the helmet mounting system and the associated helmet structure?

IIRC, 1,800-3,000# per side. The helmet breaks, not the mount. The connecting pins are mil spec certified to a double shear strength of 8,000#.

You assume the helmet shell and mounting system will be able to take the 1500# impact shock?

Yes, see above.

Do you assume the shock to the helmet mounts will be evenly divided between the two sides?

In the calculations presented above, yes. If all the load is taken only by one shock the theoretical strength is sufficient for 100Gs rather than 200Gs.

Keep in mind that these calculations represent a worst-case scenario that is extremely difficult to imagine, i.e. the assumption that the load placed on the restraint is not limited by the side/rear of the cockpit, or head surrounds on the seat of we are considering a tin top. In other words, the restraint gets no help at all. (We prefer crash testing this scenario, BTW.)

Obviously the rods are strong enough to withstand more loadings than we will ever reasonably be able to exert in normal operation. However, if the driver's head happened to be turned full left, to see where he was headed (I understand he has reasonably free movement as long as the movement is made normally?), and then the car had a severe (100g) direct rear impact, would not the limiting factor be the integrity of the helmet structure and its ability to withstand the intrusion load of the rod being pushed through the helmet?

Ah, good question. The limiting factor would be the helmet’s ability to withstand the intrusion of the mount. This is a product of the strength of the helmet and the perimeter of the mount. The latter is approximately 6”, about the same of the HANS mount.

(BTW, IIRC safety factor is typically noted as K sub t, not K sub s.)

Please do not get me wrong. I have no problems with the device. Yours simply does things differently than the HANS.

I understand. These are all good questions.

[R. Pare]

Looks like, contrary to the claims by some, that the HANS is NOT hinderance at all to an emergency exit of a tin-top, at least according to Tony Stewart, who had to exit quickly after his car caught on fire last weekend. He claims that it didn't slow him down at all, even in spite of his never practicing an emergency escape.

Lets hope that this puts an end to some of the rhetoric we've seen.

[Gregg Baker]

We are pleased Tony managed to accommodate the HANS ("I just slowed myself down and twisted my shoulder a little different.") and avoided injury. He would prefer using anything else.

100% of cases of drivers being trapped in burning cars by a head a neck restraint have involved a product that has to be worn, principally the HANS device.

And...

"I unbolted myself and undid everything and I was standing on the door, but with the HANS device you can't reach up to get out," he said.

"It is a very claustrophobic thing and you can see liquid (petrol) coming out all over the place. I shut the engine down straight away, but of course everything is still pretty hot. I had to wait for someone to come and open the door for me."

From: http://www.heraldsun.news.com.au/com...E39478,00.html

[R. Pare]

Amasing the editing that can go on to "support" ones' views!

From The Indianapolis Star, Friday April 22 : "..and said that he wasn't hindered getting out of the car by his HANS devise, which he admitted surprised him. "To be honest, I felt like I got out pretty easily....."

Give it up, Gregg. We all realise that you want to promote your own product, which isn't a bad devise, but to keep doing so by slamming the opposition smacks of charlatanism. Your crap has gone on long enough.

[Gregg Baker]

Amasing (sic) the editing that can go on to "support" ones' (sic) views!....

Agreed. Let's stick with the facts and let drivers make their own decisions.

Fact #1: X% of HANS users get trapped in their cars by the product.
Fact #2: 0% of Isaac users get trapped in their cars by the product.

It's not slamming a product and it's not debatable. It's a fact.

[Radicalone]

Greg lets do stick to the facts.

Fact #1: The I$$AC is not FIA approved.
Fact #2: The I$$AC is not SFI approved.
Fact #3: The I$$AC is not SCCA approved.

Everyone has the same opportunity to get their product approved.
You should get the proper approvals before selling safety equipement.

How many drivers would buy a drivers suit or helmet that didn't have the proper approvals just because the builder said their unapproved was better.Your product doesn't have to be better than the HANS to get approved it just has to meet the minimum standards set for that type of product.If it meets those standards then get it approved .Until then you should stop the sales pitches.

[dc]

I think the self-promotions, attacks and bickering sessions have gone on long enough.


The sky is green, no the sky is orange, no the sky is pink...