Speed Raycer

I went with the Issac (I always forget how to spell it) system. I've been paying pretty good attention to some of the discussions over on IT.com as well as a very long thread on specmiata.com. Great info on that site with the man behind Issacc, Gregg Baker, providing great insight and details on both the Issacc the HANS as well as other H&N restraints. Issacc has made almost every detail of their tests public and has opened themselves up for inquiry. The thread on specmiata.com has quite a bit of back and forth between the HANS faithful and Gregg. Make your own decision on the results.

ANYTHING is better than nothing. After smacking a concrete barrier HARD in a sideways slide while looking into my pregnant wifes eyes on the other side of the wall I woke up and started searching for a H&N restraint. I went with the Issac for the lateral restraint possibilities that I just didn't see in the HANS.

Carl Byck

Sorry, but I definitely do not see the Hans device as being superior by any great measure to the D-Cel/Simpson(same). In fact from what I can see both the Isaac, and the D-Cel are substantially superior in side impacts to the Hans. In Nascar, and other pro venues there are often far more other side impact counter measures that do not exist in most of our cars(as noted earlier). I see no convincing evidence that the Hans is the only answer. To those who posted links to the Hans testing, there is a lack of data on competeing devices, it is noteworthy that the Isaac, and the D-Cel both list hans performance side by side with their info. If you read every link posted in this thread9as I have) you will not say that it is clear cut. Also, the statement that you have to re-adjust the D-Cel is not accurate, once on, you simply attach the two clips to your helmet, there is no re-adjustment that I can see from session to session. Day to day, yes adjustments are needed. As was stated previosly, side impacts are at least as threatening, and the threshold for major injury is lower than that of a front impact. that said, I tghink for most of us the Hans may not be the best choice. This has little to do with money, so read ALL the links, and then comment. Pay special attention to the balance of other safety equipment being used in each test, and then compare that to what you are iusing, or plan to use. i will invite both Hans, and D-cel to comment on this thread. Carl

DamonB

I still haven't found the article that I referred to earlier (not that I've looked hard yet) but the key was it was performed as a true scientific experiment. I could be fooling myself but again what I recall was the "strap" devices other than HANS performed very well until a certain threshold was reached and then their ability to limit injury was nearly non-existent. The HANS could protect even with much higher crash energies than the others. I don't recall where the Isaac fell in the mix.

Side impact is more of a job for the seat. You're not going to get much help there without a strap that encircles your armpits and attached directly to the side of the helmet. The head restraints on seats are much more effective.

I'll try not to recall anymore from memory without finding the article first.

fdracer

why is the g-force device only compatible w/ g-force helmets, you still have to drill the helmet don't you? also, why don't they just invent a helmet harness similar to a seatbelt harness that attaches to the chassis and then just clips on to the back of your helmet. this will be the strongest by far since the forward head motion is supported by the chassis instead of the drivers body. in fact the seatbelt manufacturers can even sew some adjustable straps onto the harnesses themselves and have the straps connect to the helmet. here's a crude pic. the harness and head restraint system are in blue.

Carl Byck

I believe it has todo with Snells "test line", Ask their lawyer

DaveB

I have worn the Isaac for 2 seasons now, and feel that for the money, it is the best choice for me. Before I decided to buy, I went to the PRI show and looked at each product on the market. My observations and conversations with manufacturers caused my decision to be quite simple.

Some of the things that helped me make my decision: please remember that these are personal observations.

-The HANS people didn't have time to talk with me. I am a club racer in SCCA and as such was made to feel like a tire kicker.

-The G Force person said that I couldn't use their restraint on anything but their "specially equipped" helmets. I looked at the helmet inside and saw how it was "specially equipped" and realized that they were trying to sell me a helmet as well.

-I didn't look at the Huchens because I know of instances of injury as a result of that device, so I took a pass.

- The D-Cell is a Huchens without the straps that go through the crotch and attach to the harness.

-The Wright device is really interesting, but I really didn't want to have to fab something for myself. I would rather pay a few more dollars for something I know is assembled correctly when it comes to safety equipment.

That leaves the Issac.....it was not displayed at the 2002 PRI show, but I had a number of discussions with the designer, and he sent me one on approval. After researching the company he owns, I came to realize that if he can design and manufacture a hip replacement for my body, he probably has the expertise in manufacturing as well as the research resources to understand the biomedical requirements of such a device. After I saw the crash data, I was sold.

After it was delivered, I was shortly notified that they had found an adhesive in the aerospace industry that had been tested to be as strong as the 4 bolts that attach the mounts. It was sent on along.......this allows me to mount the device without voiding the Snell warrantee. A small thing, but an instance of customer service.

I can call and talk to the person that designed and built the device any time I wish. Gregg ALWAYS returns phone calls. He is also a club racer. It is also my understanding that he appeared at the ARRC this year with a bunch of new ones and swapped them out at no cost to the owners so they could take them back to the lab and examine them.

I find it extreemly comfortable, and find also that it helps take some of the side load off which helps my neck not become so tired in a race.

db

Carl Byck

Thanks Dave, first hand input is always appreciated. Carl

RussTypeS

iTrader: (3)

Yeah he swapped mine out at the ARRC, very cool...

DamonB

Finally located one article I have read. It is in the May 2004 issue of Racecar Engineering magazine (vol14, n5). "Head Masters" by Jonathon Ingram; pgs 44-52. Back issues can be purchased at www.racecar-engineering.com

Discussed are HANS, Hutchens, D-CEL, Simpson and G-Force. I know I have read something on the Isaac as well; still looking for that one.

I seem to recall another article that had measurements of different restraints and I believe this was the Sportscar article I referred to earlier. I have not found that one as I must have inadvetantly thrown my copy away. Still looking...

Here is a link to the Racecar Engineering article "Head Masters" in the May 2004 (vol 14, n5) issue

DamonB

Discussion on another board:

http://www.specracer.com/forums/topi...33&whichpage=1

DamonB

Some SAE papers available for download at $12 each:

Integration of HANS device within F1

Sled Test evaluation of Racecar Head/Neck Restraints (this one by Melvin referred to in Racecar Engineering article)

Effect of Head-Restraint Rigidity on Whiplash Injury Risk

Importance of Seat and Head Restraint Positions in Reducing Head-Neck Injuries

Performance Evaluation of Automobile Head Restraints

Development and Field Performance of Indy Race Car Head Impact Padding

Racing Safety - Testing and Development of Driver Protective Systems (Part 2)

Racing Safety - Testing and Development of Driver Protective Systems (Part 1)

Sensitivity Analysis of the Hans Head and Neck Support

Development of An Airbag System for Fia Formula One and Comparison to the Hans Head and Neck Support

Sled Test Evaluation of Racecar Head/Neck Restraints Revisited

Atd Neck Tension Comparisons for Various Sled Pulses

Brain Injury Prediction for Indy Race Car Drivers Using Finite Element Model of the Human Head

Biomechanical Principles of Racecar Seat Design for Side Impact Protection

There are dozens and dozens more. I located these by searching "head restraint" in the SAE papers.

Carl Byck

Only 12.00 Each, I wonder if you can get them cheaper from the library of congress. The thread linked is from '02 also. Another thing to consider is how, and what movements are limited with each device. New, or different style mirrors may have to be installed once you are using one of these devices.

DamonB

"Sled Test Evaluation of Racecar Head/Neck Restraints Revisited " was presented in November of 2004. Don't get more up to date than that!

"Biomechanical Principles of Racecar Seat Design for Side Impact Protection" is also from last month but it's by Melvin and we know how you feel about his opinion (I don't find any connection between Melvin and HANS. Melvin is retired from GM Research and is now a consultant as well as a prof at Wayne State UNiversity. I see no direct involvement of he with HANS?). The Isaac site says it was tested at Wayne State University which is where Dr. Melvin does his research so I assume Melvin was responsible for at least some Isaac testing as well.

Seeings how magazines lag a few months behind on presenting stuff I bet we hear about some of it in the springtime.

DamonB

Lots more info on head restraints here:

http://jayski.thatsracin.com/pages/restraint.htm

Carl Byck

Actually already posted that link, but here is one article that in particular concerns me; Buying a Hans, read this first.

http://www.hutchensdevice.com/news/H...Restraint.html

You all should read this, and then ask these questions of the particular manufacturer you are considering.

DamonB

How is it that Hutchens is able to make the entire HANS device slip completely out from under the shoulder belt in a 45 g crash? That couldn't happen without having the belts loose or pulling the dummy's entire shoulder out from under the harness (which would also mean the harness was too loose).

From Hutchens site:

Carl Byck

That is a side impact, not frontal. Point is Hans says your dead in a D-Cel, but tested an old style nylon one, D-Cel says your dead in a Hans in a side impact. Tims(screen name) recently lost a friend in a low speed side impact crash. Most of us are not running proper side impact protected seats. Thus my suggestion that everyone ought to consider their entire safety system when buying one of these devices. I will most loikely be moving my Kirkey seat to the passenger side, and buying a new seat with proper head, and rib restriants for the drivers seat. ALA Ultra shield road race seat, or similar. Very few composite seats offer the level of protection the aluminum seats do as far as head, and shoulder/rib restraints. One other thing, it looks like that is a different test on the Hans, than the D-Cel (note the steering wheel). I don't know where that image came from.

here is the text that goes with that image.



" A head and neck restraint needs to compliment the system that it is working in. Early testing on HANS Devices show an increase in both neck tension and HIC when used in an entire system with a head rest. (SAE Motorsports: Melvin / Hubert Gramling). This has also been shown to be the case in independent testing done on stock car set-ups with the HANS device. In back to back tests run on the same safety cell, have shown that the differences between carbon devices and strap harnesses is greatly reduced. The strap device systems normally decrease neck tension vs the baseline, while the HANS device neck tension has been shown to increase because of the interaction with the entire system.




Added benefits with the Simpson Head and Neck Restraint are that it can not only reduce neck tension in frontal and angular frontal impacts but it can help control helmet movement in side impacts and rollovers, and it stays with the driver in multiple impact situations.



A harness type head and neck restraint has been proven to be beneficial in multiple impact situations as well as roll-overs. They are being widely used in race cars from asphalt to dirt."

Carl Byck

note, simpson, and D-Cel are the same AFAIK Carl

fdracer

again why do these harness style head restraints have to be attached to your body? it'd be so easy to have a harness attached to the chassis behind your helmet and you could just clip and unclip the harness to your helmet every time you got in and out of the car.

Carl Byck

Basicly there are three styles, Hans, which attaches to the helmet, and is secured by your shoulder belts, Issac, attaches to the seat(I think), and to your helmet, and D-Cel, which is a full body harness attached to your helmet. Each uses a different "anchor" From what I can see, I like the D-Cel, since it stays with you regardless of position, and helps substantially in side impacts. The Hans seems to be the best in a single impact frontal collision,but as soon as your shoulder harness is moved in relation to your helmet, looses efficasy. And the Issac, which also looks good, but there is not alot of data published for the public on. All have comprehensive studies done, but each only publicizes the part of the test, or type of test within which it performed the best, LOL.

DaveB

The SAE conference just finished this past Thursday in Indy. One of the major discussions at the conference was in regard to side impact crashes. If you would like to keep up with more of the discussion, look for gsbaker on the Improved Touring forum. He attended the conference, and is the designer of the Issac. Gregg posts often there and is forthcoming with lots of information.

The Isaac attaches between the shoulder harness and the helmet. It uses 2 small aerospace shock absorbers to control movement of the head, and as such, is quite linear without the finite STOP point of the devices with straps.

Regardless of your preference, it is really important to use some sort of restraint.

db

DamonB

I undestand, that was my point. Regardles of device the shoulder harness will still hold the dummy in place. How is it that the Hutchens test shows HANS can get out from under the shoulder strap without the dummy also moving and yet the same not happen with the other devices? Seems you would have to have the shoulder straps quite loose for that to be possible, regardless of what type of head restraint.

Carl Byck

Damon, I must not be understanding what you are saying, the dummy is moving sideways in all three images. The D-Cel does not depend on, or even use the shoulder harnesses to restrict head movement. It (D-Cel)is self contained, thus why it may be better in multiple impacts, and is undeniably better in side impacts. We don't know at what time in relation to the impact each frame was taken, thus my point, ALL the manufacturers sites are HYPE, and only the SAE papers will answer your questions(possibly). Even the SAE papers and their associated research are being done in cooperation with(at a minimum) the manufacturers, who know full well which impact types their device will fair the best( and are likely slanting the research that is published. I think a debate between you and me, or anyone else on here is not valuable without the full SAE papers. Once we have a good range of technical documents, we can read them, and then debate the merits from there. I woder alot about the SAE paper on sensitivity of the Hans to set up. If your shoulders slope excessively, you have a long/short neck, or some other physical feature that prevents the "off the shelf" Hans from fitting correctly, at what point does the device loose efficasy, and to what degree. The whole thought of a "one size fits all(rigid) device like the Hans makes me a sceptic. So the same piece that fits me at 5'9", and 150lbs, is sold to a 6'2" 300lb driver??? I am sceptical of all of these test, as NONE are in full context, and all are meant to be testimonials for there respective devices. It seems to me that the major sanctioning bodies have looked at all the data, my question remains, why is it relatively unavailable considering its importance. Once again the answer is that none of these devices are "THE ANSWER" IMHO. Anyway, let's see what kind of response we get from the manufacturers. Carl

tims

Carl,
Sorry for the long response time. I researched seats a year ago and have seen very new seats that beat the one I recommend. Racetech (http://www.racetechseatsna.com/start.html) is making the best(by far) composite/carbon seat(short of PPI's $10,000 driver pod). The aluminum seats including the Ultra Shield models are just not strong enough. The custom Butler and LaJoie seats are the only aluminum seat that is even close(these start at about $4000). One of the problems with aluminum is it can and does deform and fail at the welds. This happened in my friends crash. the bottom of the seat broke at the welds. My comment about the adjusting of the strap type systems is that if you read the directions. They show you where the straps need to be located on your body to be effective. once all the straps are adjusted the first time it seems likely that it would stay in adjustment, but for it to work it has to be in the specific location specified in the directions. I would want to be sure the strap is one inch below my neck line before needing it to save my life. This is what I was referring to. It should be checked every time it is removed and installed. Also all of these devices are designed to restrain your head in a frontal or rear impact not side impacts. some do a better job but if you contact the manufacturers(yes, I did) and ask about side impacts they will all claim they are not as effective. The seat has to be the side impact restraint. It is also to restrain the head not absorb impacts, so the seat should be very close to the head and not move or flex. I know these seats are not cheap neither are the head restraint systems, but they are needed and should be installed in all levels of race cars. I would at least install the sprint car type window net on the inside while you save for your new head and neck restraint seat. this has been shown to work very well for low dollars. Good luck and make the changes soon.

Carl Byck

Tim, thanks for the insight. I am Contemplating Retrofitting the new Ultrashield seat at this point. This will entail externally reinforcing the existing structure, and gusseting/doubling if appropriate. The welding will be done by a certified welder, and friend who understands the importance of the quality of the work. Those other seats are beyond my means, and I accept the associated risks. Racing is inherently dangerous, on balance, my efforts will match the risk I percieve. Thanks again, Carl