For Your Viewing Pleasure [Archive] - Improved Touring Racing Forums

Chris Wire

12-15-2005, 02:40 PM

Quick question.

I did as instructed and right-clicked and selectec "Save Target As" and then copied them to my hard drive. I did the HANS vid first, and when that was 30% loaded I selected the ISAAC vid and loaded that. The ISAAC vid caught the HANS vid at 48% loaded, and was fully installed while the HANS was still at 69%.

Now, am I supposed to read anything into that??? ;) ;)

BTW, the video was VERY enlightening to those of us who are still on the fence and haven't yet decided on a type of restraint. I had heard of belt slippage issues on the HANS before, but this is the first visual proof I have seen.

Gregg, what effect do you think a sternum strap would have made? I have used those in the past and that's the first thing I thought of when I saw the HANS vid.

gsbaker

12-15-2005, 02:55 PM

Originally posted by Chris Wire@Dec 15 2005, 02:40 PM
Quick question.

I did as instructed and right-clicked and selectec "Save Target As" and then copied them to my hard drive. I did the HANS vid first, and when that was 30% loaded I selected the ISAAC vid and loaded that. The ISAAC vid caught the HANS vid at 48% loaded, and was fully installed while the HANS was still at 69%.

Now, am I supposed to read anything into that??? ;) ;)
Sure. It means that the Isaac makes you go faster. :)

BTW, the video was VERY enlightening to those of us who are still on the fence and haven't yet decided on a type of restraint. I had heard of belt slippage issues on the HANS before, but this is the first visual proof I have seen.

Gregg, what effect do you think a sternum strap would have made? I have used those in the past and that's the first thing I thought of when I saw the HANS vid.

68372

The problem with the sternum strap is that it can get caught under your chin. If you put it low enough to avoid that, it may be too low to work. Because the combination of harness, seat and driver are different, the driver won't know if he has it right until he crashes.

gsbaker

12-15-2005, 03:06 PM

Originally posted by Bill Miller@Dec 15 2005, 02:24 PM
Gregg,

Thanks for posting those. The way I read it, the two devices sure seem to perform similarly (although seeing the HANS pop out from under the belts is a bit unsettling). How will this impact (no pun intended) getting the ISSAC SFI 38.1 certified?

68368

We will certify it, but SFI won't because it is excluded by section 2.5. If SFI omits that section, which has nothing to do with head loads, they will certify it.

JamesB

12-15-2005, 03:33 PM

what does the section mandate? I am no rules nerd, and I dont even know where you find the SFI spec rules.

gsbaker

12-15-2005, 03:43 PM

Single point release:

http://www.hmsmotorsport.com/docs/SFI_38.1...ecification.pdf (http://www.hmsmotorsport.com/docs/SFI_38.1_Head_Restraint_Specification.pdf)

charrbq

12-15-2005, 05:07 PM

I've got my own opinion of sternum straps. I had heart surgery several years ago (about 6 yrs. before resuming a racing hobby), and I felt like the sternum strap would be a good thing. My cardiologist later told me that the cables and regrowth of cartilidge made my sternum stonger than o.e. I shared the car with a friend who, with the assist of a Corvette, put it into the wall hard enough to destroy the car and almost himself. He still suffers from the whip lash (no head and neck restraints were on the market at this time), but the bruise to his chest and heart made by the sternum clasp was of more concern to the O.R. doctor than the neck injury. I ditched the strap and bought regular ones. And of course, built a new race car.

Eagle7

12-15-2005, 09:56 PM

Originally posted by gsbaker@Dec 15 2005, 03:43 PM
Single point release:

http://www.hmsmotorsport.com/docs/SFI_38.1...ecification.pdf (http://)

68380

This link is broken.

Thanks,

Catch22

12-15-2005, 10:22 PM

This test was obviously very similar to Renee's actual crash. Two things jump out at us...

1. We're really glad she was wearing the Isaac.
2. Now we fully understand why her shoulders were so badly bruised from the harness (the worst injury she sustained).

Thanks Gregg!
:smilie_pokal:

gsbaker

12-16-2005, 08:40 AM

Originally posted by Eagle7@Dec 15 2005, 09:56 PM
This link is broken.

Thanks,

68412

Thanks Marty. Let's try again:

http://www.hmsmotorsport.com/docs/SFI_38.1...ecification.pdf (http://www.hmsmotorsport.com/docs/SFI_38.1_Head_Restraint_Specification.pdf)

Dave Burchfield

12-16-2005, 09:24 AM

Gregg,

After reading the SFI specs, it's pretty obvious that there was some coaching when they were written. ............and that's really unfortunate.

Be sure to look out the window Monday.......I'll be the one waving as I go by!

Dave

gsbaker

12-16-2005, 09:52 AM

Originally posted by Dave Burchfield@Dec 16 2005, 09:24 AM
Gregg,

After reading the SFI specs, it's pretty obvious that there was some coaching when they were written. ............and that's really unfortunate.

Be sure to look out the window Monday.......I'll be the one waving as I go by!

Dave

68440

:006: :)

R2 Racing

12-16-2005, 10:19 AM

Wow, interesting video. Seeing the HANS pop out from under the belt isn't very confidence inspiring.

Gregg, I'll be in contact. :023:

Greg Gauper

12-16-2005, 12:25 PM

That is a very misleading video, IMHO.

First off, those belts do not seem to have been snugged down sufficiently. It looked like there was way too much body movement. The belts have to be very, very snug in order for the HANS to work properly. When I first used my Hans, I felt 'loose' in the seat. Once we determined that you had to really snug down on the belts, I felt very secure. Prior to that we were tightening the belts 'the way we always did'.

Second, most of us do not race on a flat metal plate for a seat lacking any lateral support, such as what was tested. We racing on racing seats which do provide some lateral support. Some better than others.

Third, even though the belts slipped on the Hans, look very closely at the video and compare the total amount of head movement and neck travel of the Hans user to the non-Hans user. The Hans user still had less head and neck travel, inspite of not being used correctly i.e. the belts too loose and slipping out.

Lastly - In actual real world crashes, how often do the belts come loose in the manner shown in the video? Anybody see Brakke's crash (A Hans user) in this years E-Prod race on Speed? (If not, there is a nice photo sequence on the Prod website taken from the pit wall) Did his belts come loose? How about that IRL fire-ball crash this year by the Target driver? Did his belts come loose? How about the dozens of Nascar drivers that crash every week (probably the highest number of events to evaluate)?

To me, all that video shows is that if you don't use the safety equipment properly i.e. snug your belts down properly, proper mounting angle (which BTW is what contributed to Earnharts death), decent racing seat with some lateral support, then the Hans might not be as effective as another device.

Edit - added link to Brakke's crash. It's on the 6th page of the thread, about halfway down:

http://www.coloradoscca.org/prodcar/viewto...r=asc&start=100 (http://www.coloradoscca.org/prodcar/viewtopic.php?t=5031&postdays=0&postorder=asc&start=100)

gsbaker

12-16-2005, 01:26 PM

Originally posted by Greg Gauper@Dec 16 2005, 12:25 PM
...To me, all that video shows is that if you don't use the safety equipment properly i.e. snug your belts down properly, proper mounting angle (which BTW is what contributed to Earnharts death), decent racing seat with some lateral support, then the Hans might not be as effective as another device.
68475

Okay, but the Isaac system works all the time. No ifs, ands or buts.

To the objective observer, the video asks the question, "Why would anyone use a HANS when they can use an Isaac system?"

The belts, BTW, are extremely tight. You are seeing a 180# man X 68Gs = 12,240#. Some of it is belt stretch, some of it is the body changing shape.

VW16VRacer

12-16-2005, 06:53 PM

Gregg

What year is the HANS in this test. My HANS is a year old and it has a lip on the outside edge to help keep the seat belts in contact with the frame of the device along with a more agressive textured surface.

I also agree with Greg, the belts IMHO do not look tight, at least not as tight as I run mine. I am also using the Recaro SPG HANS seat that not only has a lot of support but ample wings to add to the safety and support in a offset crash. I have been thinking about adding a sernum strap for just this, but will rethink it after seeing this. I am in no way a P.E. so I could be totaly off on this......

Now I will not argue with you on your design that it works with the belts snug or tight. You are right on that one.

Jon Bonforte

ddewhurst

12-16-2005, 07:14 PM

Gregg, while watching the action of the Isaac several times I have a couple questions from my observation.

A. Does the Isaac roller & bracket which is around the harness act as a brake along with the area of harness with the light colored stiching as the helmet end of the Isaac is comming forward & in a downward direction ?

B. During tests is a measurement taken as to the length of Isaac piston rod extention ?

C. What approx distance dose the test shoulder harness stretch or approx how far forward dose the shoulder move ?

D. What approx distance dose the lap belt stretch ?

If these are no answer questions just say so.

Thanks <_<

gsbaker

12-16-2005, 07:36 PM

These are all good questions, but they are going to have to wait. We can publish detailed loading data that determines whether a driver lives or dies but the reaction pales in comparison to when we post a simple video of a crash test.

I think our server has melted.

Everyone have a good weekend. :)

Dave Burchfield

12-16-2005, 11:17 PM

Interesting comments by many so far.............I witnessed a test of another device being crashed at the Delphi site in Vandalia. I stood at the sled as the Delphi technicians strapped the dummy in the seat. They spent near an hour fussing over how everything was assembled.

After seeing in person the care and professionalism of the staff at Delphi, it is my humble opinion that there is little, if any chance that ANY test being conducted is not at optimum.

Please remember, this facility tests a host of parts in use by most major auto manufacturers where there are billions of dollars of product liability at stake. They don't take chances.

Disclaimer: I am not now or ever have been associated in any way with Delphi.

db

gsbaker

12-17-2005, 08:48 AM

Originally posted by VW16VRacer@Dec 16 2005, 06:53 PM
Gregg

What year is the HANS in this test. My HANS is a year old and it has a lip on the outside edge to help keep the seat belts in contact with the frame of the device along with a more agressive textured surface.

Ah, then you have the version that came out about a year ago. People tend to refer to it as the 2005 model. The one we tested was older. I'd like to see the videos of the newer one.

I also agree with Greg, the belts IMHO do not look tight, at least not as tight as I run mine. I am also using the Recaro SPG HANS seat that not only has a lot of support but ample wings to add to the safety and support in a offset crash. I have been thinking about adding a sernum strap for just this, but will rethink it after seeing this.

The seat has to help. Be careful with the sternum strap, though. If too high it could choke you; if too low it may not work. People aren't sure how to tune them. It may be a case of them working great if you don't hit anything very hard, so why bother.

Of course, with the sternum strap you violate the single point release rule, but don't get me started. ;)

gsbaker

12-17-2005, 08:55 AM

Originally posted by Dave Burchfield@Dec 16 2005, 11:17 PM
Interesting comments by many so far.............I witnessed a test of another device being crashed at the Delphi site in Vandalia. I stood at the sled as the Delphi technicians strapped the dummy in the seat. They spent near an hour fussing over how everything was assembled.

After seeing in person the care and professionalism of the staff at Delphi, it is my humble opinion that there is little, if any chance that ANY test being conducted is not at optimum.

Please remember, this facility tests a host of parts in use by most major auto manufacturers where there are billions of dollars of product liability at stake. They don't take chances.

Disclaimer: I am not now or ever have been associated in any way with Delphi.

db

68545

Interesting indeed, Dave. Racers have asked us to test to SFI protocol and do a side-by-side against the HANS device. So we do, and what happens? :rolleyes:

Dave is right, everyone. The Delphi lab is very good. We handed them the products, the helmets, a check and said, "Here, run the SFI 38.1 offset for us." Anyone can walk into the lab and do the same thing, and get the same results.

M. Hurst

12-18-2005, 12:46 AM

As Paul Harvey sez...The rest of the story.

1. HANS passes the offest test even with only one side of the collar under the belt.

2. They don't put those big shoulder and head restraints on nextel cup cars for looks.

3. Those belts are tight, the forces are big.

4. So far no test data from Isaac on the straight frontal test.

Opinion: In conditions without seat head restraints, the Isaac would probably perform better than HANS in offset tests, especially at greater angles.

gsbaker

12-18-2005, 09:48 AM

Well said.

So what is it you believe a HANS device does better than an Isaac system? Seriously, I'm not trying to sound like a wiseguy, and we are aware that a HANS with a 4-belt harness will probably outperform an Isaac system in a pure frontal crash.

Knestis

12-18-2005, 12:42 PM

... First off, those belts do not seem to have been snugged down sufficiently.

I don't know about this test individually, but my understanding is that Delphi staff do the testing and I would assume that they understand the importance of tight belts.

Second, most of us do not race on a flat metal plate for a seat lacking any lateral support, such as what was tested. We racing on racing seats which do provide some lateral support. Some better than others.

You are onto something VERY important here, Greg. This is one major shortcoming of the SFI test. This is supposition on my part but, as someone who gathers data for a living, if I were designing the 38.1 protocol and knew that evidence suggested that I could expect strong interaction effects between seats, harnesses, and H&N systems, I might leave the seat out of the equation for the sake of "fairness." Test protocols like this require - first and foremost - repeatability. (This is why I strongly doubt that harnesses were looser in either test.) If Delphi used, say a RECARO SPG Racer like mine, it would be possible for people to accuse the test of being biased against a particular H&N system, the design of which for whatever reason doesn't jive with that seat.

Third, even though the belts slipped on the Hans, look very closely at the video and compare the total amount of head movement and neck travel of the Hans user to the non-Hans user. The Hans user still had less head and neck travel, inspite of not being used correctly i.e. the belts too loose and slipping out.[/quote]
Again, I don't know the numbers involved in these specific tests but remember that it isn't MOTION that kills you. What we really care about is the reduction of the loads imposed on the connection between noggin and neck.

... if you don't use the safety equipment properly i.e. snug your belts down properly, proper mounting angle (which BTW is what contributed to Earnharts death), decent racing seat with some lateral support, then the Hans might not be as effective as another device.

Abso-damn-lootly. The basis of our complaints with SFI 38.1 is that it tests H&N systems to a minimum standard, completely out of context of the real world of real racers, in real race cars, hitting real stuff, real hard. This is what headrestraint.org (http://www.headrestraint.org) is responding to. Instead of a standard, the sole purpose of which is to indemnify sanctioning bodies and manufacturers, we should have a way of reporting head-load force reductions in a variety of conditions, in a variety of crashes.

I should be able to ask a H&N manufacturer how well their system works with MY seat, in MY type of car - and they should have some motivation to find out, so they can provide me and other safety consumers with that information. As it is, SFI requirements by sanctioning bodies pose a huge DISINCENITVE to testing any protocol besides 38.1

Why, for example, would any manufacturer in the current environment want to test a broadside crash into a tree (all but certainly the most fatal situation for rallyists), when they have nothing to gain by doing so? Why don't Rally America and NASA Rally demand this kind of testing? Because the manufacturers and SFI have given them an easy out with 38.1. Who suffers? Racing consumers, who get a dumbed-down "yes/no" test and a list of "approved" devices - tested against a protocol that SFI itself tells us (at its lawyers' prompting, no doubt) shouldn't be used to compare the performance of systems.

K

Bildon

12-18-2005, 01:35 PM

I agree with the others that neither belt appears to be tightened properly. What also concerns me even more is that the belts on the Hans dummy are 2" to 3" looser than on the ISAAC dummy. You can see this in frame #1 by looking at the metal adjusters relative to the lettering on the T-Shirt.

Where is the real SFI test data for both tests? Or was this only a private Delphi test? This is a life and death matter and all the facts should be laid out for all to see. This SFI test data must have been published if these tests have been performed on the HANs and ISAAC, no?

I would like to hear the HANS viewpoint as this is scary stuff. :(

Knestis

12-18-2005, 01:44 PM

Again, likely in the interest of repeatability, I'll bet that the testers didn't remount the harnesses to put the adjusters in the right place on the HANS dummy's chest. Remember that the HANS frame is going to take up some room - the same as would happen if one put a thicker-chested person in the harness, where it had been adjusted for, well, me and the adjusters will naturally ride higher up toward the collarbone.

Yet ANOTHER limitation of the test protocol: The same dummy gets used, so the same harness adjustments get used.

K

EDIT - The further issue is that there is no such thing as "SFI test data." The protocol reports dichotomous data (or binary, if you choose), like pregnancy test - a system either passes or fails. (And I'll let you decide which is which, in the pregnancy analogy!)

Bildon

12-18-2005, 02:17 PM

>> there is no such thing as "SFI test data."

Oh come on! Just because the product is rated on a "pass-fail" basis doesn't mean their wasn't a 'shload' of data generated to reach that conclusion.

I found this with a little research.
http://www.ogracing.com/files/SFI_testresults_web.jpg

Would like to see more data on the test in the video.

lateapex911

12-18-2005, 03:30 PM

I am REALLY doubtful that the tests were conducted with the belts "loose" as has been opined here. That's just basic science...and any test conducted by a facilty such as this, HAS to be a bit more advanced than "basic science"....

This whole SFI thing is VERY scary....it really is a massive diservice to us, the racers...we are all led down this path that results in the companies and the SFI padding their pockets, and the racers assuming they are protected in the best manner possible.

Add to that TV commentators with the inevitible comment after a bad crash. "Good thing he was wearing a HANS...probably saved his life"...riiight..like they have a CLUE to the actual forces imparted on any driver in any crash..

It is unfortunate that the HANS in this test wasn't the current model, and that "realspeed" video wasn't availble so we can see how it happens in real time.

Knestis

12-18-2005, 04:47 PM

Sorry - I wasn't clear. SFI doesn't PUBLISH data, even though there is indeed a lot of it squeezed out of the process.

K

gsbaker

12-18-2005, 07:21 PM

Okay, several things quickly:

1. We have a real time video, shot with a camcorder on a tripod. Someome please remind me to get it posted if you don't see it in a couple of days. Rather dull, actually, until one considers 1/2 million pounds of thrust runs the sled from a dead stop to 40+mph in about 30 inches. No audio though. :(

2. We received the final package of data on Wednesday, so we've had only two days to work with it. The first priority was the video and enough of a review of the data to offer a verbal summary. There was much more to this test series than what has been presented here. In six months at two labs (Wayne State being the other) we ran a total of 4 crash tests on three designs to put some meat on this whole single-point-release/SFI issue.

We are swimming in data. Video too. Five cameras. It should all be enroute to headrestraint.org soon.

3. Everything about this test is very precise, including the belts. The techs spent nearly an hour getting the dummy prepped properly. With the HANS device, which they have hit many times, the belt adjusters are supposed to be at a particular location relative to the bottom of the HANS yoke (don't know why). Also, the HANS requires more belt so everything had to be reset. The belts are tighter than a driver could ever load them.

Knestis

12-18-2005, 07:36 PM

Originally posted by gsbaker@Dec 18 2005, 06:21 PM
... With the HANS device, which they have hit many times, the belt adjusters are supposed to be at a particular location relative to the bottom of the HANS yoke (don't know why). Also, the HANS requires more belt so everything had to be reset.
Interesting. Exactly the opposite of what I guessed.

K

gsbaker

12-18-2005, 08:26 PM

Dave,

Sorry it took so long to reply.

Originally posted by ddewhurst@Dec 16 2005, 07:14 PM
Gregg, while watching the action of the Isaac several times I have a couple questions from my observation.

A. Does the Isaac roller & bracket which is around the harness act as a brake along with the area of harness with the light colored stiching as the helmet end of the Isaac is comming forward & in a downward direction ?
No, there is enough clearance for the double-thickness of belt to pass without any friction. I'm glad someone spotted that. Now you can see why we suggest a minimum length of free travel in front of the belt connector. If you hit something hard enough you may need it.

B. During tests is a measurement taken as to the length of Isaac piston rod extention?
Yes. It was extended too far, over 60% of travel. Also, the helmet mounts are too far to the rear.

C. What approx distance dose the test shoulder harness stretch or approx how far forward dose the shoulder move?
I'd have to measure it off the lateral camera.

D. What approx distance dose the lap belt stretch?
Same answer. Sorry, all that is at work.

If these are no answer questions just say so.

Thanks <_<
Anytime

tderonne

12-18-2005, 10:24 PM

Quick comment, a little off topic, but relevant to some comments above.

FIA seats are tested to survive a 15 to 20 g load.

What g load did these tests see?

(A few have mentioned the Recaro SPG seat. It meets FIA.)

gsbaker

12-18-2005, 10:44 PM

Originally posted by tderonne@Dec 18 2005, 10:24 PM
Quick comment, a little off topic, but relevant to some commenst above.

FIA seats are tested to survive a 15 to 20 g load.

What g load did these tests see?

(A few have mentioned the Recaro SPG seat. It meets FIA.)

68662

Tim,

The sled is capable of ~80Gs, but the spec calls for a nominal peak load of 68Gs, and the computer controls that well.

Seats are the issue in pure lateral testing, i.e. 90 degree offset. There are different styles, so some debate as to which is most representative. Then you have to remove everything above the shoulders to isolate the contribution from the H&N restraint. Plus they tend to blow up.

That's one reason we like this 30 degree offset test. The lateral component alone is 34Gs (68 x sin(30)) and the lateral head torque is measured independent of other head loads, so we get a very good idea of how well the product protects the head against side loading, with or without a seat. We figured we would do well in this measure, but really got an early Christmas present--an 85% reduction in lateral head torque. A real double take.

And the left shock reaction that reduced the lateral torque held the belt on. What's that old saying? I'd rather be lucky than good.

Bildon

12-18-2005, 11:54 PM

Gregg,
Thanks for those clarifications. hmmmmmm
Great, now I'm not going to sleep so well :(
I'm going to be dreaming about 30 deg. impacts :unsure:

planet6racing

12-19-2005, 11:28 AM

Originally posted by M. Hurst@Dec 17 2005, 11:46 PM
As Paul Harvey sez...The rest of the story.

1. HANS passes the offest test even with only one side of the collar under the belt.

2. They don't put those big shoulder and head restraints on nextel cup cars for looks.

While the HANS does pass with only one side under the belt, there is a rotational component of the head as a result that scares me as an engineer. Additionally, any additional contact beyond the first impact is compromised by the HANS no longer being properly supported.

Secondly, why should they have to put those restraints in if there is something that can be just as effective, yet give the visibility back to the drivers?

One last thing- just in the interest of full disclosure (OK, two things) - M. Hurst - could you reveal who you are? This is the second board you've commented on and you seem pretty knowledgeable regarding the Head and Neck restraint testing. And, as most on this board know, I am Bill of "All Hail Bill!" fame and do have ties to the Isaac product, not just as a user.

M. Hurst

12-19-2005, 12:32 PM

Originally posted by planet6racing@Dec 19 2005, 10:28 AM
One last thing- just in the interest of full disclosure (OK, two things) - M. Hurst - could you reveal who you are? This is the second board you've commented on and you seem pretty knowledgeable regarding the Head and Neck restraint testing.

I've built and raced a couple of IT cars, but not since 2001. I've been involved with the SCCA since 1980, where I started as a worker at Nelson's Ledges.

I've been a Pro-Rally and Club Rally competitor since 1982, and won the 2001, 02, 03 Club Rally national championships in Group 5.

I was the SCCA Club Rally Series Manager in 2004, and am starting my second year as technical director of Rally-America.

My position(s) have allowed my to participate in and attend testing with Hubert Gramling (who has also attended our events) and the FIA, Dr. John Melvein (IRL, OWRS), and NASCAR's Steve Peterson.

I was also a mechanic / pit crewman for 3 time Winston Cup champion David Pearson, 1983-85, and crew chief for a local ARCA and LMSC team.

So I have ties to the SFI foundation (they certify my scruiteneers) and the FIA, but none to HANS or any other manufacture.

..You may claim I'm part of a vast conspiracy against the Isaac, but my opinions, (Isaac won't pass the 38.1 frontal test) are just opinions, and probably academic given the SFI stand on the single release. I would be happy to be proven wrong by a sled test, because I also believe the dashpot idea is a promising one, I just don't believe they work well enough to pass 38.1 when attatched at a steep angle to the helmet (at rest), because this is common trait of all the devices (reaction link not approximately horizontal) that have failed to meet 38.1.

The Hutchens failed, a collar was added to make the reaction link nearly horizontal, and it passed.

Like I said, ..please prove me wrong.

Mike Hurst
Technical Director
Rally-America
SAE6115318102

gsbaker

12-19-2005, 12:33 PM

Originally posted by Bildon@Dec 18 2005, 11:54 PM
Gregg,
Thanks for those clarifications. hmmmmmm
Great, now I'm not going to sleep so well :(
I'm going to be dreaming about 30 deg. impacts :unsure:

68669

I wouldn't lose any sleep over this. The HANS device is a good product. When used properly--proper belts and good lateral support--it will work well. My concern is that amateur racers don't recognize the importance of lateral seat support--or, put another way, think that they are as safe as a NASCAR or F1 driver with their vacuum-fit cockpit.

You have to keep things in perspective, also. 68Gs is a massive blast. We put enough cushion into component design to be good for ~120-150Gs; titanium versions to ~150+. At some point it all gets a little silly for most racers.

Knestis

12-19-2005, 01:10 PM

I appreciate you chiming in here, Mike. I think the rally perspective, while not necessarily DIRECTLY related to IT-type cars on road courses, can be very useful. (But I'm kind of a rally guy, myself.)

Knowing the RA is now an SFI sanctioning body member, I'd be interested in your thoughts about SFI 38.1 specifically - not what it takes to pass it, but whether or not it is a sufficient approximation of "real crashes" in context (particularly as relates to rallying), or if it provides sufficient evaluative power to be useful to racers.

A cynic (and to be fair, you need to know that I include myself in this group) might suggest that the purpose of SFI is to protect member sanctioning bodies and manufacturers, but is it doing so to the detriment of individual racers' ability to make informed decisions about H&N systems?

Part of the SFI standards charter says that specifications will be revisited when warranted. Particularly with an eye on rallying, is there any movement to do this? Are you satisfied that the current standard is sufficient, to the degree that we can expect RA to issue a 38.1 requirement?

Thanks for contributing to an important conversation.

K

gsbaker

12-19-2005, 01:30 PM

Originally posted by lateapex911@Dec 18 2005, 03:30 PM
...It is unfortunate that the HANS in this test wasn't the current model, and that "realspeed" video wasn't availble so we can see how it happens in real time.

68636

http://www.isaacdirect.com/images/Video/DelphiSled.avi

Don't blink. ;)

~7.5MB

Please right click, save as.

gsbaker

12-19-2005, 03:10 PM

Originally posted by M. Hurst@Dec 19 2005, 12:32 PM
...You may claim I'm part of a vast conspiracy against the Isaac,
There is no conspiracy Mike, but there are some assumptions about what causes head loads that have been proven incorrect. That nonsense should have died with the last millennium.

...but my opinions, (Isaac won't pass the 38.1 frontal test) are just opinions....I would be happy to be proven wrong by a sled test
We can arrange that. Tell you what, we'll all meet at Delphi and hit an Isaac system of your choice (even the Link) head on. You say it will flunk, I say it will pass. I'll buy the beer and the loser pays the lab fee.

And we could have a contest. Whoever gets closest in guessing the final number wins. If the Isaac passes they get a free Isaac; if the Isaac fails they get a free HANS.

Anyone up for this?

...I just don't believe they work well enough to pass 38.1 when attatched at a steep angle to the helmet (at rest), because this is common trait of all the devices (reaction link not approximately horizontal) that have failed to meet 38.1.
They have a common trait, but that's not it.

M. Hurst

12-19-2005, 04:43 PM

Originally posted by gsbaker@Dec 19 2005, 02:10 PM
We can arrange that. Tell you what, we'll all meet at Delphi and hit an Isaac system of your choice (even the Link) head on. You say it will flunk, I say it will pass. I'll buy the beer and the loser pays the lab fee.

If you claim that your device can meet all of the impact test result criteria of 38.1, then the financial (and moral) obligation is on you to perform all of the impact tests of 38.1 and prove these claims.

I'm not selling anything. ..'cept maybe Isaac devices if you're right.(figuritively)

I can be at delphi in less than 2 hours.

planet6racing

12-19-2005, 05:33 PM

Do you have to hit the same device the required number of times for the SFI test, or do you change it after each test? It'd sure be interesting to run 3 tests on one Isaac and one helmet and one belt set, then do the same for the HANS...

M. Hurst

12-19-2005, 06:18 PM

Originally posted by planet6racing@Dec 19 2005, 04:33 PM
Do you have to hit the same device the required number of times for the SFI test, or do you change it after each test? It'd sure be interesting to run 3 tests on one Isaac and one helmet and one belt set, then do the same for the HANS...

68706

I brought up this point at a roundtable discussion last year, but was interupted by someone from the IRL who said "statistically there is no second major impact". This may be the case for Indy cars on ovals with spotters, where chain reaction wreck are less common now, but I thought it would be a design consideration (NASCAR Talledega?).

A second major impact would be rare because you've lost all of the car's energy on the first impact, but not impossible...and the most important point is the survivability of the occupant, not the device.

...but I can imagine getting turned into the wall at Road America's kink, and then sitting on the track and getting blasted by another car who's not heeding the caution, =2 big impacts

If you ever have a big impact, throw out all the safety equipment, and the seat too.

In answer to your question, in general, a new device and belts for each test.

Edit: BTW, It would be interesting to see one straight frontal test on the Isaac, much less three.

gsbaker

12-19-2005, 06:18 PM

Originally posted by M. Hurst@Dec 19 2005, 04:43 PM
If you claim that your device can meet all of the impact test result criteria of 38.1, then the financial (and moral) obligation is on you to perform all of the impact tests of 38.1 and prove these claims.

I'm not selling anything. ..'cept maybe Isaac devices if you're right.(figuritively)

I can be at delphi in less than 2 hours.

68702

C'mon Mike, I thought you were convinced we'd fail the test. Don't you want free beer?

gsbaker

12-19-2005, 06:34 PM

Originally posted by planet6racing@Dec 19 2005, 05:33 PM
Do you have to hit the same device the required number of times for the SFI test, or do you change it after each test? It'd sure be interesting to run 3 tests on one Isaac and one helmet and one belt set, then do the same for the HANS...

68706

I think the Spec calls for fresh belts each shot. We've hit the same helmet there more than once, but, of course, it had the magic adhesive. :D

We could probably hit this Isaac again, because it looks fine, is dimensionally correct and the dampers are smooth. I don't trust some of the metal components, though.

The HANS cracked in two places. Probably just a fluke; the lab techs were very surprised, and Dr. Trammel recommend replacement at the 100G limit.

Chris Wire

12-19-2005, 06:41 PM

Originally posted by gsbaker@Dec 19 2005, 02:10 PM
And we could have a contest. Whoever gets closest in guessing the final number wins. If the Isaac passes they get a free Isaac; if the Isaac fails they get a free HANS.

Anyone up for this?

Free is my favorite four letter word!

Count me in.

gsbaker

12-19-2005, 07:09 PM

Mike,

I understand your position on the straight vs. offset test, but we are not going to waste time running a test when we already know the outcome--especially a simple pass/fail test.

We are not aware of any comparative testing which resulted in the frontal load being higher than the offset load. When we crash tested the Wright Device earlier this year, John Melvin told me, "You may as well do the offset. If you can pass that you can pass the frontal."

This relationship is also illustrated by SFI's own numbers: the passing offset level is 4,000N, the passing frontal level is 3,200N. Same with the HANS device. They are advertising the frontal loads at ~16XX, and the offset loads are higher.

I see what you are getting at concerning the damper possibly functioning differently in the two tests--that's an interesting element you have brought up--but it doesn't pencil out when we run the numbers. All said and done, there is no reason why the loads would actually increase to 3,200N rather than decrease.

gsbaker

12-19-2005, 07:12 PM

Originally posted by Chris Wire@Dec 19 2005, 06:41 PM
Free is my favorite four letter word!

Count me in.

68712

Sounds like time for a road trip!

M. Hurst

12-19-2005, 07:30 PM

Originally posted by gsbaker@Dec 19 2005, 06:09 PM
This relationship is also illustrated by SFI's own numbers: the passing offset level is 4,000N, the passing frontal level is 3,200N. Same with the HANS device. They are advertising the frontal loads at ~16XX, and the offset loads are higher.

No, the passing level for the frontal impact is 4,000N.

If the results of the first two frontal impacts are less than 3,200N, you're excused from a 3rd impact. A device can pull 3,999N frontal three times and still pass.

Do you have a copy of 38.1?

By your logic, since at least 2 frontal impacts are required, but only 1 offset, then the frontal is tougher than the offset?

I say the offset is tougher for the HANS, because of design.

Chris Wire

12-19-2005, 07:30 PM

Originally posted by gsbaker@Dec 19 2005, 06:12 PM
Sounds like time for a road trip!

68716

Can't do the road trip but would love another contest. I missed the last one by that l---------------------------------------------------l much!

gsbaker

12-19-2005, 07:43 PM

Originally posted by Chris Wire@Dec 19 2005, 07:30 PM
Can't do the road trip but would love another contest. I missed the last one by that l---------------------------------------------------l much!

68718

That's right Chris, I remember. You were very close.

A contest may be a good idea. It's always entertaining and boosts interest. Hmmm, any ideas? We're flexible.

Or we could have a sale. Perhaps a discount on all those old Isaac systems, "old" meaning we now certify them to meet SFI 38.1 performance specs, but we haven't lazer engraved the new label. :D We'll provide a certificate on parchment, suitable for framing.

Ooo, I like that one.

Thoughts anyone?

gsbaker

12-19-2005, 07:56 PM

Originally posted by M. Hurst@Dec 19 2005, 07:30 PM
No, the passing level for the frontal impact is 4,000N.

If the results of the first two frontal impacts are less than 3,200N, you're excused from a 3rd impact. A device can pull 3,999N frontal three times and still pass.
Correct, provided the Nij is no greater than 1.00. Good point.

Do you have a copy of 38.1?
I do.

By your logic, since at least 2 frontal impacts are required, but only 1 offset, then the frontal is tougher than the offset?
No, I'm saying that throughout the history of crash testing, offsets have always produced higher head loads than frontals.

I say the offset is tougher for the HANS, because of design.
I suppose that's possible because some of the load reporting is inconclusive, but it is our understanding that other designs produce similar results. I don't have a fundamental disagreement with your theory, Mike, I just don't see our numbers jumping to 3,200 from 2,211. Perhaps HANS should test the Isaac. :)

Knestis

12-19-2005, 08:38 PM

I'm kind of hoping that Mike will respond to my questions about the substance of 38.1, rather than focusing conversation just on meeting it. I wasn't asking rhetorically - I'd really like to get firsthand perspective on what it all means.

K

M. Hurst

12-19-2005, 10:43 PM

Originally posted by Knestis@Dec 19 2005, 07:38 PM
I'm kind of hoping that Mike will respond to my questions about the substance of 38.1, rather than focusing conversation just on meeting it. I wasn't asking rhetorically - I'd really like to get firsthand perspective on what it all means.

K

68726

What's generally regarded as fatal neck loads, (4,000N) at the highest repeatable level we can test at (68G), frontal and 30deg offset.....I'm OK with that. There was talk from the SFI to update the seat belt standards to the level (68G?) of the H&N standard...good.

I would like to see them require 2 offset tests (demonstrate repeatability).

The single point of release...Yes for Rally, but Isaac release pins wouldn't bother me so much on a race track.

The seat and dummy position....The flat steel seat is not real-world representative, and no device gets any help from it, but there's so many variable with seats, that it's probably best to stick with it the way it is.

Is it applicable to rally? A definite yes considering the possibility of a frontal or low offset hit on a tree very near the road with almost no reduction in speed. No H&N device is going to help much when the tree trunk comes through the car and nails you in the side of your head. For that we need better cage standards (In progress) and a padded structure between the occupant's head and the outside of the car.

Another thing that bugs me about the tests I've seen: The tech and safety experts fidget for hours over mounting everything perfectly to the sled, getting the straps in the perfect position etc. I can see needing to do this to eliminate variables, but what about the real world where everything's not so perfect? How about Rally where you're bouncing out of a ditch before you nail that tree? The hardest hit I ever took was after doing a 360 on my roof! After the techs are done setting the dummies perfectly, I'd like to reach up and kick the dummy in shoulder, or mount the seat with a 40deg lean and duplicate a real world crash.

One more point, and I hope Mr. Baker will agree: There is a tendancy to oversimplify, and say "I'm safe because I have a H&N device"..which is like saying "My car is fast because it has a K&N filter". The mounting and angle of the belts, the relationship of the H&N device, belts, and seat, the seat and it's mountings, the strength of the cage, padding, and its location relative to the occupant..all of this has to be viewed as a complete system...but it still ain't safe, it's racing.

Knestis

12-19-2005, 11:38 PM

Thanks, Mike - I appreciate the input.

K

lateapex911

12-20-2005, 03:05 AM

This is a GREAT discussion.

I'd like to direct this to Mike, as he seems to have lots of experience, but I'd appreciate anyones thoughts as well.

I may as well put my foot in my mouth right away....in my crashing experience, I have never hit anything "square on". There has always been rotational (yaw?) aspects, and the hit has always been offset. Broke a couple ribs on the seat slapping the guardrail after being "turned" at Watkins Glen this summer.

Thats just my experience though.....what does the historical crash data tell us about the real world probablilities???

Or, if I were to look at purchasing a H&N restraint, and one of the factors influencing my decision was crash performance, would I be wise to weigh heavily the devises' offset performance ....more than the straight frontal performance????

tderonne

12-20-2005, 09:47 AM

Side nets...

ddewhurst

12-20-2005, 09:53 AM

Hi-jack

Posted by Mike.

***For that we need better cage standards (In progress) and a padded structure between the occupant's head and the outside of the car.***

Mike, if you have any data or test data on driver protection relative to door tubes please pm me @ [email protected] Example true NASCAR parallel tubes intruding into the door cavity & what I'll call the Rally "x".

Thanks

Knestis

12-20-2005, 10:14 AM

Originally posted by lateapex911@Dec 20 2005, 02:05 AM
.....what does the historical crash data tell us about the real world probablilities??? ...

That's a hell of a good question.

One complaint that the headresraint.org proeject is trying to address is that issues like this get lost in the quest for repeatability. SFI 38.1 assures that a system will react in a particular way to ONE SPECIFIC crash. Is that the crash that we need to be protected from, that is most likely to inflict the injuries that H&N systems are supposed to prevent?

Particularly as more and more cars get data acquisition systems, we should be able to learn more about the complex dynamics involved. I was pretty sorry that I didn't have the DL1 on when I rolled at Rally TN. It doesn't handle Y-axis accelerations but it would still have been interesting.

K

gsbaker

12-20-2005, 10:29 AM

Originally posted by M. Hurst@Dec 19 2005, 10:43 PM
...I would like to see them require 2 offset tests (demonstrate repeatability).
I disagree, and I'm disappointed that there is more than one frontal required. The reason is science and statistics. There will be little variation in the results given that the variables are so closely controlled--same input, same output.

If you have two numbers you have no idea where they fall on the distribution curve. Only a t statistic will help and for that, with an acceptable level of confidence, you need ~30 tests. Won't happen.

It might boost the feel-good factor, but there is no practical conclusion one can draw from multiple tests. It is much more productive performing variations with computer simulations.

The single point of release...Yes for Rally, but Isaac release pins wouldn't bother me so much on a race track.
You really need to speak with pro EMTs on this one, Mike. They much prefer leaving everything back in the car. For a conscious driver, I suggest you poll some of the users on this forum.

The seat and dummy position....The flat steel seat is not real-world representative, and no device gets any help from it, but there's so many variable with seats, that it's probably best to stick with it the way it is.
Is it applicable to rally? A definite yes considering the possibility of a frontal or low offset hit on a tree very near the road with almost no reduction in speed. No H&N device is going to help much when the tree trunk comes through the car and nails you in the side of your head. For that we need better cage standards (In progress) and a padded structure between the occupant's head and the outside of the car.
Agreed.

another thing that bugs me about the tests I've seen: The tech and safety experts fidget for hours over mounting everything perfectly to the sled, getting the straps in the perfect position etc. I can see needing to do this to eliminate variables, but what about the real world where everything's not so perfect? How about Rally where you're bouncing out of a ditch before you nail that tree? The hardest hit I ever took was after doing a 360 on my roof! After the techs are done setting the dummies perfectly, I'd like to reach up and kick the dummy in shoulder, or mount the seat with a 40deg lean and duplicate a real world crash.
They love seeing us show up at the crash lab...

How to test an Isaac system.
Step 1: Put helmet on dummy.
Step 2: Connect Isaac to belts. Click, click.
Step 3: Connect Isaac to helmet. Click, click.
Step 4: Push big red button.

One more point, and I hope Mr. Baker will agree: There is a tendancy to oversimplify, and say "I'm safe because I have a H&N device"..which is like saying "My car is fast because it has a K&N filter". The mounting and angle of the belts, the relationship of the H&N device, belts, and seat, the seat and it's mountings, the strength of the cage, padding, and its location relative to the occupant..all of this has to be viewed as a complete system...but it still ain't safe, it's racing.

68731

Big agreement there. :023:

gsbaker

12-20-2005, 10:46 AM

Originally posted by Knestis@Dec 20 2005, 10:14 AM
That's a hell of a good question.

68760

...with a very scary answer, I think.

A lot of crash data is not published, but the rumor we're hearing regarding the pro series is that the largest hits are lateral. I'll type that again so everyone knows it's not a typo: ...the largest hits are lateral, and frequently involve more than one impact.

With the belts coming off the HANS device, that's not good. Any way you look at it, you can only be confident of a HANS device if you have excellent lateral support or you only crash head on.

Granted, much pro racing is roundy-round and it would be reasonable to assume different crash types in road racing, but this explains why the new tin top seats are CF over beads/foam. Cost? Don't ask.

JIgou

12-20-2005, 11:52 AM

Originally posted by M. Hurst@Dec 19 2005, 05:18 PM

...but I can imagine getting turned into the wall at Road America's kink, and then sitting on the track and getting blasted by another car who's not heeding the caution, =2 big impacts

Uhhmmm......yeah. Luckily #1 impact into the wall wasn't too bad, so I didn't get to do the full test...but I still got to replace my car.

I'd put "multiple impacts" high on the list of possibilities.

Jarrod

M. Hurst

12-20-2005, 12:00 PM

http://www.joieofseating.net/seat_photos/Saturday_Night_Special_Seat.jpghttp://www.kirkeyracing.com/images/seats/53000.jpg

A couple of the latest seats (mass produced) with proper lateral support for the head and shoulder area.

Lajoie and Kirkey

gsbaker

12-20-2005, 12:15 PM

The seat will need over 3,000# of lateral strength above the waist to hold up to the offset SFI test.

Are these strong enough for that, Mike?

Bill Miller

12-20-2005, 12:29 PM

Originally posted by M. Hurst@Dec 20 2005, 12:00 PM
http://www.joieofseating.net/seat_photos/Saturday_Night_Special_Seat.jpghttp://www.kirkeyracing.com/images/seats/53000.jpg

A couple of the latest seats (mass produced) with proper lateral support for the head and shoulder area.

Lajoie and Kirkey

68772

Mike,

Those both look like stock car / short track seats. I have the Kirkey Road Race seat, and from it's design, it does not look to be adaptable to the lateral head support. I am curious as to what the design considerations are for a short track / oval track seat vs. those for a road race seat.

M. Hurst

12-20-2005, 12:32 PM

Originally posted by gsbaker@Dec 20 2005, 11:15 AM
The seat will need over 3,000# of lateral strength above the waist to hold up to the offset SFI test.

Are these strong enough for that, Mike?

68773

Both seats have mounting / reinforcement points in the shoulder / neck area for mounting to the cage...strong enough?..I think we're about to find out.

gsbaker

12-20-2005, 12:39 PM

Originally posted by M. Hurst@Dec 20 2005, 12:32 PM
Both seats have mounting / reinforcement points in the shoulder / neck area for mounting to the cage...strong enough?..I think we're about to find out.

68778

The cage? That oughta do it. :)

M. Hurst

12-20-2005, 12:44 PM

Originally posted by Bill Miller@Dec 20 2005, 11:29 AM
Mike,

Those both look like stock car / short track seats. I have the Kirkey Road Race seat, and from it's design, it does not look to be adaptable to the lateral head support. I am curious as to what the design considerations are for a short track / oval track seat vs. those for a road race seat.

68777

The head and shoulder supports are not "add ons" on these seats, the bases are designed for the supports (which in some cases are seperate pieces).

The seats appear to be symmetrical, and by the manufacturers claims, suitable for road racing. If I remember right from the PRI show, the Kirkey model shown did have a longer head support on the right side.

Remember, you don't want the head support without the shoulder support!

The old, alumimum "flap" type head and shoulder supports were useless in crashes.

Lajoie offers an "add on" system to bolt to an old-stlye common aluminum seat (any mfg), "safer system" on their website.

http://www.joieofseating.net/seats.html

http://www.kirkeyracing.com/seats.html

planet6racing

12-20-2005, 01:22 PM

Not knowing exactly how these will mount to the cage in those areas....

I have to question the ability for that seat to absorb energy if it is that rigidly mounted in those areas. One of the biggest arguments held here (and we are NOT going to re-hash it!) is that the rear seat support for a non-FIA rated seat is actually a back breaker. I'd be concerned regarding a similar aspect here.

I still, as a road race, do not want one of those seats. I like to be able to see, to look ahead, and to turn my head to check the corner station at the last second...

gsbaker

12-20-2005, 02:14 PM

You don't want a head surround providing lateral support. It just obscures your vision and hinders egress.

You want your Isaac system providing lateral support.

M. Hurst

12-20-2005, 02:31 PM

Originally posted by planet6racing@Dec 20 2005, 12:22 PM
Not knowing exactly how these will mount to the cage in those areas....

I have to question the ability for that seat to absorb energy if it is that rigidly mounted in those areas.

The seats not supposed to "absorb" energy, it's supposed to spead the load out evenly on the body. Your back needs to be held in place in relation to the chassis while the car is crushing and absorbing energy. This is not just my opinion, ask any recognized motorsports safety expert in the world.

The human body can withstand 100+G impacts without injury if it's supported well enough, (and no intrusion)...the IRL proves this almost every weekend!..They're basically sitting on a padded section of the tub!

A seat theat flexes very much is going to snap back (or break). The flexing that feels good for a 10 G impact can be fatal at 50G. H Gramling (FIA) had some interesting videos of rear impact testing of FIA seats, with the seatbacks breaking and subsequent (obviously) fatal loads.

gsbaker

12-20-2005, 02:43 PM

Those IRL Gs are resultant values, typically with very short durations.

Bill Miller

12-20-2005, 05:10 PM

Originally posted by M. Hurst@Dec 20 2005, 12:44 PM
The head and shoulder supports are not "add ons" on these seats, the bases are designed for the supports (which in some cases are seperate pieces).

The seats appear to be symmetrical, and by the manufacturers claims, suitable for road racing. If I remember right from the PRI show, the Kirkey model shown did have a longer head support on the right side.

Remember, you don't want the head support without the shoulder support!

The old, alumimum "flap" type head and shoulder supports were useless in crashes.

Lajoie offers an "add on" system to bolt to an old-stlye common aluminum seat (any mfg), "safer system" on their website.

http://www.joieofseating.net/seats.html

http://www.kirkeyracing.com/seats.html (http://www.kirkeyracing.com/seats.html)

68781

Mike,

This is the seat I'm talking about

http://www.kirkeyracing.com/images/seats/43000.jpg

I've tried the circle-track seats, and don't find them well suited for road racing, especially in an IT or closed Prod car. I honestly don't see how the head supports from the other seats will work w/ the above pictured seat.

tderonne

12-20-2005, 11:53 PM

So there's going to be an SFI spec for seats? As I mentioned, the FIA test is a bit of a joke. Sounds like the SFI spec will be much better.

Racer Chris

12-21-2005, 11:18 AM

Gregg,
On the Production Racing Forum David Finch has made what amounts to a veiled accusation that the Hans video is intentionally skewed by your company. I don't believe David's theory but to dispel the air of partiality he is working to create could you answer a couple of questions for me?
Did Isaac pay for the HANS test? Were the arm restraints set up differently with any intent to change the test results? Did Delphi knowingly conduct the tests with different parameters? Any other info you have to close this issue would be helpful.
TIA,
Chris Foley

gsbaker

12-21-2005, 12:04 PM

Originally posted by Racer Chris@Dec 21 2005, 11:18 AM
Gregg,
On the Production Racing Forum David Finch has made what amounts to a veiled accusation that the Hans video is intentionally skewed by your company. I don't believe David's theory but to dispel the air of partiality he is working to create could you answer a couple of questions for me?
Did Isaac pay for the HANS test? Were the arm restraints set up differently with any intent to change the test results? Did Delphi knowingly conduct the tests with different parameters? Any other info you have to close this issue would be helpful.
TIA,
Chris Foley

68846

Chris,

We figured this would happen. The solution is very simple: Have SFI make public the video of the same test. Or HANS for that matter. If they have one video of the belts not coming off, I'm certain the world, including their customers and sales reps, would love to see it.

We contracted with Delphi to perform the 38.1 test. We pay for all of our testing. We'd be more than happy to use someone else's money, however, so feel free to send some. Neither HANS nor SFI would disclose the data, so that was the only way to get it.

Talk is cheap. If some turkey thinks the results are rigged, let them prove it by getting different results with the same test. Of course, if that happens one must call into question the test protocol, but that's another issue.

erlrich

12-21-2005, 12:12 PM

Originally posted by Racer Chris@Dec 21 2005, 11:18 AM
Gregg,
On the Production Racing Forum David Finch has made what amounts to a veiled accusation that the Hans video is intentionally skewed by your company. I don't believe David's theory but to dispel the air of partiality he is working to create could you answer a couple of questions for me?
Did Isaac pay for the HANS test? Were the arm restraints set up differently with any intent to change the test results? Did Delphi knowingly conduct the tests with different parameters? Any other info you have to close this issue would be helpful.
TIA,
Chris Foley

68846

No so veiled, actually. Here is a link to that discussion for anyone interested. Prod Forum (http://www.coloradoscca.org/prodcar/viewtopic.php?t=5454&postdays=0&postorder=asc&start=0)

David's comments do raise a few questons, though, which the answers to could put some of his accusations to bed: were the two tests run on the same day; who requested/paid for the tests; and were there any special testing requirements other than "run the SFI test"?

Also Gregg, I have to ask, from purely a marketing standpoint (keeping in mind I am an accountant and know almost nothing about marketing :D ), why would you not go ahead and hit the Isaac in a frontal impact, just to be able to say you did it, and it passed with flying colors, and we have now passed all of the 38.1 performance requirements, blah, blah, blah, and more importantly to silence the critics who like to use this as a point of criticism? I realized the test is expensive, and probably unnecessary, but wouldn't the marketing value almost offset the cost?

****EDIT: sorry Gregg, you and I were typing at the same time, you obviously type faster (I want a rematch!). Please disregard those questions you've already answered above :D ****

gsbaker

12-21-2005, 12:29 PM

Earl,

If we were to conduct the straight fontal impact--which would result in an upper neck tension value of between 1,700 and 2,100 Newtons of force--skeptics would claim we rigged it. The only value to conducting that test is if SFI drops section 2.5, so why should we bother?

It is a very simple matter to prove us wrong. Between HANS, SFI and others there must be a dozen plus videos of the HANS device on that same sled running SFI 38.1 offset. So post one.

Now, if someone wants to make a little wager...

Matt Rowe

12-21-2005, 01:03 PM

I'll also put forth the same question I asked on the production forums. If the motion of the driver's arm can cause such an obvious issue with the Hans device where should a driver put his hands in the event of a crash. (and don't say take them off the wheel, we all already know that one) Seriously though if the simple act of having the drivers wrist held near his thigh causes the hans to slide from under the belts that doesn't seem like a robust design. Later models may have improved on that, but when did the change occur and how much testing has been done to verify the fixes works in a wide variety of situations?

And Gregg, it's great that you "know" the frontal impact numbers will be low, but we would all still like to see the proof.

dave parker

12-21-2005, 01:12 PM

Originally posted by gsbaker@Dec 21 2005, 11:04 AM

Talk is cheap.

68849

Words to live by.

cheers
"dangerous" dave parker

gsbaker

12-21-2005, 01:34 PM

Originally posted by Matt Rowe@Dec 21 2005, 01:03 PM
...Later models may have improved on that, but when did the change occur and how much testing has been done to verify the fixes works in a wide variety of situations?
I'm not sure there ever was a fix. That lateral load is severe, so I'm not sure the changes are enough to make a difference at 70Gs. That change came out last fall, IIRC.

And Gregg, it's great that you "know" the frontal impact numbers will be low, but we would all still like to see the proof.

68855

Sure, that would be nice for the record, but we can't get very excited about it. Doing something you know you can do is like kissing your sister.

Now, if you want to hit an Isaac system head on, the place to do it is on a 100G sled in Michigan. Let's run some round numbers:

Say the Isaac intermediate does 2,000N head on at 70Gs. Extrapolating that to 100Gs (not always accurate, but there is no other way to go) gets us ~2,850N, which works. The fun part though is hitting the $295 Link model on that sled. It may not make the 3200N limit, but it looks good for the 4,000N limit Mike mentioned. If it doesn't work as presently configured we can switch the webbing to Kevlar. A <$500 product good for 100Gs is worth going after.

If Mike can produce evidence that a crash dummy anywhere, on any sled, experienced more upper neck tension in a direct frontal impact than it did in an offset impact, we'll test it direct frontal. But that doesn't happen. That's why the normal SFI limits are lower for frontals. Sure, they will let you get away with the higher offset number, but only after failing the frontal test twice.

Bill Miller

12-21-2005, 07:23 PM

gsbaker

12-21-2005, 07:55 PM

Originally posted by Bill Miller@Dec 21 2005, 07:23 PM
To me, David Finch's comments are tantamount to slander (or is it libel?, one is written, the other is spoken). I've asked him to substantiate his claim, or retract it.

68894

Slander is spoken; libel is written.

We occasionally see this. It has never come to it, but we have had counsel prepped to move. Amazing how many self-annointed experts there are out there.

Hey, if I'm an electrician, I'm not going to tell the plumber he's wrong.

A wager usually works. :)

M. Hurst

12-21-2005, 08:08 PM

Originally posted by gsbaker@Dec 21 2005, 12:34 PM

That's why the normal SFI limits are lower for frontals.

Please stop making these false statements, :angry: or are you claiming to meet a performance specification that you don't comprehend and have not run all of the tests for?

The frontal limit is 4,000N, same as the offset.

At least two frontal pulls are required, but only one offset.

If neither of the first two frontal pulls exceeds 3,200N, then a third frontal pull is not required. Since multiple frontal pulls are required but only one offset pull, the SFI must consider the frontal pull to be significant.

gsbaker

12-21-2005, 08:24 PM

Originally posted by M. Hurst@Dec 21 2005, 08:08 PM
Please stop making these false statements, :angry: or are you claiming to meet a performance specification that you don't comprehend and have not run all of the tests for?

The frontal limit is 4,000N, same as the offset.

At least two frontal pulls are required, but only one offset.

If neither of the first two frontal pulls exceeds 3,200N, then a third frontal pull is not required. Since multiple frontal pulls are required but only one offset pull, the SFI must consider the frontal pull to be significant.

68902

Mike, don't pretend to know what I comprehend, please. It's very simple: Can you provide any evidence that frontal loads are higher than offset loads--for any dummy on any test sled, anywhere?

Edit: On reflection, taking an absolutist approach like this does nothing to further the discussion. One may be able to find an example of frontal loads being higher than offset loads, but that's not the point. The point is that there is no scientific evidence to suggest that direct frontal loads are ~45% greater than offset, the value at which the Isaac system would fail to pass the SFI frontal test, i.e. 3,200N.

M. Hurst

12-21-2005, 08:48 PM

That's your theory (off set loads always higher), fine.

My theory says you still need to do a frontal test.

Everyone's entitled to their theories and opinions,but we shouldn't misrepresent the facts.

You have misquoted SFI 38.1 as proof of your theory, twice in this thread. After being corrected, and yourself admitting the error, you mis-state it again.

erlrich

12-21-2005, 09:47 PM

Ok, in the interest of fairness, here are the pertinent sections of the spec, verbatim - you guys decide:

5.1.3 PROCEDURE

B. The test sled shall be propelled to produce the racing acceleration pulse (Figures 2A and 2B) at a nominal 68G peak, 70 KPH (43.5 mph) velocity change. A minimum of two (2) frontal tests and one (1) 30 degree right frontal test will be required. To be considered valid tests, the results of each of the frontal tests must be 3,200 N or less. If the frontal results fail to meet the above requirement, then a third frontal test will be required and none of the three values shall be above the maximum requirements per paragraph 6.1.1 The 30 degree right frontal test must meet the requirements of paragraph 6.1.1.

6.1.1 IMPACT PERFORMANCE FOR EACH TEST (procured from Hybrid III test device).

Maximum Upper Neck Tension 4,000 N (899 lbs.)
Maximum Upper Neck Compression 4,000 N (899 lbs.)
Maximum Value of NIJ 1.0

To my feeble brain this means SFI would prefer to see two frontal tests at less than 3,200 N, but if you can't meet those requiremenets we'll let you get by with 4,000 N if you run a third test and all three are under 4,000 N. That also implies to me that loads between 3,200 - 4,000 N are considered to be in the marginal range, which tells me that I would want nothing to do with a system that couldn't get below 3,200. JMHO of course.

gsbaker

12-22-2005, 07:52 AM

Thank you, Earl.

lateapex911

12-23-2005, 02:39 AM

Who actually wrote the SFI requirements? Who do they (or him/her) work for? What was the arrangement that produced the results we just read?

Bill Miller

12-23-2005, 10:39 AM

Originally posted by gsbaker@Dec 21 2005, 07:55 PM
Slander is spoken; libel is written.

We occasionally see this. It has never come to it, but we have had counsel prepped to move. Amazing how many self-annointed experts there are out there.

Hey, if I'm an electrician, I'm not going to tell the plumber he's wrong.

A wager usually works. :)

68901

Thanks Gregg, couldn't remember which was which. I noticed that Mr. Finch has stated that he will not retract his comments. Merry Christmas! :023: :happy204:

gsbaker

12-23-2005, 11:46 AM

Don't worry Bill, if the Delphi test of the HANS device was somehow flawed, HANS/SFI will produce all of the test videos showing the belts staying on.

<SoundofCrickets>...</SoundofCrickets>

Merry Christmas!

gsbaker

12-23-2005, 12:49 PM

Originally posted by lateapex911@Dec 23 2005, 02:39 AM
Who actually wrote the SFI requirements? Who do they (or him/her) work for? What was the arrangement that produced the results we just read?

69062

I expect it would be a combined effort of SFI, it's members and possibly outside consultants.

Knestis

12-23-2005, 01:08 PM

pgipson

12-23-2005, 03:24 PM

The basis of my concerns with the SFI system starts with the fact that its membership includes both the sanctioning bodies that require that standards be met, and the manufacturers that sell the stuff that meets them...

Kirk

I don't think that is such an unusual relationship. Most standards setting bodies operate in similar fashion. maybe not through memberships directly, but certainly through collaboration between industry, users and regulators. And all of the ones I am familiar with in aerospace rely on suppliers for the bulk of their financial support. The subject matter experts are found in industry, not in the standards organizations.

Knestis

12-23-2005, 05:26 PM

Okay - I'll bite. give me an example of a situation in the aerospace industry that "operates in a similar fashion."

To clarify the "fashion" that I'm talking about...

1. Manufacturers and sanctioning bodies join SFI
2. They - with SFI - develop standards
3. Tests get done, stuff gets approved
4. Santioning bodies demand that racers in their series use that stuff
5. Manufacturers sell that stuff, passing on the price of testing and SFI tags to the racers
6. SFI makes money
7. Manufacturers and sanctioning bodies decrease liability exposure claiming that they are adhering to "standards"

Why WOULDN'T they love this system? Why WOULD you, as a racer?

Replace "SFI" in the above example with "AIAA" and fill in the rest of the steps for me.

K

gsbaker

12-23-2005, 05:44 PM

I agree with Pauls (?) analogy to a point, as I spent several years in aerospace as well. But the primary difference is crucial: only those affiliated with the development of the HANS device were consulted in writing the spec. Gee, guess what the spec looks like?

In 2002 I met with SFI at the SAE conference to discuss the standard. We recommended a graduated scale represented by a percentage head load reduction, similar to SFI's specs for drag racing roll cages.

Two years later, without any further communication with us, SFI announced a spec that excluded every product on the market except the HANS device.

I agree that the expertise lies with the manufacturers, who are closest to the R&D and willing to invest in it, but that's not what's happening.

pgipson

12-23-2005, 09:02 PM

Replace "SFI" in the above example with "AIAA" and fill in the rest of the steps for me.

We can use RTCA in the example (except the FAA doesn't join). Or SAE. Or Arinc. I said the model is similar and it is.

But the environment is also open. And that is Gregg's point about the difference.

My point is that the expertise lies with the developers, not with the standards writers.

Knestis

12-23-2005, 11:14 PM

Originally posted by pgipson@Dec 23 2005, 08:02 PM
... My point is that the expertise lies with the developers, not with the standards writers.

That much is absolutely reasonable, no question.

I do evaluation work for a living and I've found that it's easy to get bound up in methodologies, data collection, and analysis to the detriment of doing really important things like explicating the purpose of any given evaluation or research effort. THAT'S where I have difficulty with 38.1.

Drivers and their families operate as if that standard defines some level of protection when evidence strongly suggests that the purpose of the process has everything to do with indemnification of manufacturers and sanctioning bodies. If different stakeholders understand the purpose of the standard differently, then it doesn't matter what the actual test IS.

I would LOVE to convene a panel of engineers, doctors, EMTs, critical care nurses, constructors, racers, and sanctioning body people to revisit the whole range of possible responses to the needs of drivers buying H&N systems - with industry needs set aside completely.

K

lateapex911

12-24-2005, 02:35 AM

Well put Kirk...

My issue is that the entire "standard setting" amounted to essentially ONE company writing their own standard, and the SFI going along with it.

Maybe I am missing something, but it appears that the bottom line here is a HUGE conflict of interest.

Any standard that is set based on the input from essentially one organization is, in my mind, a farce, regardless of whether the actual standard is good or not! With no other input they are totally lacking any system of checks and balances.

My gut reaction is, if indeed the HANS organization, and it's research partners were the sole contributers of the standard, then it is probably not a good standard after all.

To my untrained eye, it appears the standard favors devices that perform well straight on, and it gives significantly less value to offset hits...but in the real world, is that what really happens?

Perhaps there is scince that can interpolate data to give a bigger picture, but I have always theought reality was the best test.