quote:Originally posted by Juan Lopez
I have downloaded the paper and it basically says that the Hutchens (and another similar device from Safety Devices I believe) basically are not effective at all. The HANS resulted OK on all tests with consistent results.

HANS basically reduces impact forces ont he neck by over 50% more than the others. ISAAC or SSR were not tested.

I guess then Bells statement is just a legal thing, as there is no mention that the restraint devices don't work. The contrary, HANS apparently really works and the others tested dont.

Can't post the article due to copyright status.

Juan

Juan,

The ISAAC system was tested using the described protocol, i.e. same crash dummy, same crash sled, same crash impulse, same test lab (Wayne State University Bioengineering Center). See SAE paper #2002-01-3306. I also can't post due to the copyrights having been assigned to SAE.

The G-Force SRS was also tested under the same conditions. The results were not published by SAE, but have been published in various G-Force catalogs.

The combined results are here—see the second chart (yes, I’m with the Isaac company):

http://www.isaacdirect.com/html/chart.html


I am looking at many helmet restaint systems. Here is what I think. There is very little science out there or proven fact. There are unproven concepts proven under ridgid test protocol that may or maynot have real world bearing. HANS seesm to have the most data and real work results. Evan HANS has only about 5000 devices in use (I think that is from their website.

The problem with the strap devices like hutchens, gforce, simpson's and there was a free one on the web, is that knowbody has specs for how tight the straps should be. The manufactures don't have a spec or rule of thumb to tell me.

The SAE paper I think said that the effectiveness on these devices was related to the tightness on the strapping devices and small adjustments changed the G's on the head by huge amounts.

The Hans is a fixed no brainer if you have the shoulder harness attached. Also the HANS is the standard.

I have never used an ISSAC nor seen one only read the website. The paper physics sounds good but I am easy to impress only having physics 101. The ISSAC is a theory not proven in the real world. It also has those shocks that have parts subject to failure. The speed dynamics of their shock is absolutely critical to the device working or not working. There is no way to field test the unit or know if the shocks are giving out. We have all had shocks die the slow death. That is what makes the hood of your car slowly not stay up as the shocks slowly give up. At what point does the Issac loose efficiently. Everything in a crash happens in milliseconds. Can the shocks really be dependable? Other comments?

 

This product looks very promising and it looks like you are trying to be more reasonable than the other vendors regarding the cost. I particularly like your mounting system which doesn't require the helmet to be drilled. Good luck and please keep us informed of future developments!

BTW, I wouldn't worry too much about the shock dynamics over time although nothing beats empirical data. Do shocks have a shelf life or do they wear out from use? If the latter is the case I hope to never have to use your product (or anything similar) over the course of many many years.

 

From “Fatbillybob”:

Any “head restraint,” strap or HANS devices, can double the head loads if worn too loosely.

Several customers have crashed without injury. These were amateurs with no Crash Data Recorders, but one bent the seat.

See below.


From Paul Foster:

We noticed early on that many racers were purchasing the Hutchens product because it was cheap, so there is a large segment of the market that is price sensitive. Our product is not made on a sewing machine, so there is no way we can offer it at a rock bottom price. However, we have a cost advantage over the HANS device because the Isaac is not worn. There are no sizes or styles, so the inventory is very low.

The adhesive mount is very popular, and works well.

The shocks wear out from use. Manufacturers who provide shocks for many industrial applications make the shocks to our specifications. For example, our shock is also built for agricultural use. It is typically replaced after a half-million cycles at full load and full stroke. This takes several years. A racer would never load the shocks that much in normal use. We have a policy of replacing any shock the racer feels may not be “right,” at no charge.

 

Previous reply:"The shocks wear out from use. Manufacturers who provide shocks for many industrial applications make the shocks to our specifications. For example, our shock is also built for agricultural use. It is typically replaced after a half-million cycles at full load and full stroke. This takes several years. A racer would never load the shocks that much in normal use. We have a policy of replacing any shock the racer feels may not be “right,” at no charge."

This is kinda funny. No racer will get 500000 cycles so the shocks just don't wear out. With that kind of life the company policy should be to not replace the shock period. It just does not break...or does it? I have experienced simple hood strut type shocks (a possibly different animal) that just **** on the shelf and loose whatever inthere that makes them work. A shock dyno is the only way to prove a shock working to spec. The Issac as sold leaves me questioning the reliability of the shocks. There needs to be some kind of verification like seeing presure on the presure guage of your fire bottle.

I am glad to see the Issac device "apparently" working. However, "Several customers have crashed without injury. These were amateurs with no Crash Data Recorders, but one bent the seat. " , is not data of appreciable sample size. This is called "luck".

I hope the Issac works since next to the HANS it seems like potentially the best device. However, HANS has become a kind of defacto standard and it is working. But damn it is expensive. OTOH cheap and dead does you know good at all. As to strap devices there is a huge variability in the devices application. The basillar skull fracture race deaths are small enough that is may take years to gather any decent meaningful numbers.

 

The Charlotte Observer has been tracking this data since 1990. Half the racing fatalities are due to basilar skull fracture--about 150 deaths during that period. On average, a driver dies every month. Here is a list:

http://161.188.204.190/charlotte/rd/index.asp

 

fatbillybob, you're being rather harsh. Yes, I understand our lives are on the line. I've "known" Gregg on-line for a couple of years now and have never found him to be anything but forthright and honest.

I am not an Isaac user (I'll probably go a different directions for my own reasons), but it's one thing to question, present other evidence, etc., but Gregg is stand-up and didn't deserve that. I know Gregg will patiently answer any questions.

Make up your own mind, but don't be outright dissing him like that.

 

The Charlotte Observer site appears to be out of date since they haven't posted any deaths since 2001.

Regarding new devices of course there is some risk using something that hasn't been fully "tested in battle". However, that certainly doesn't mean people shouldn't at least try to develop a better mousetrap that costs much less than the best device currently out there.

There have also been cases where the HANS has apparently failed by breaking and there are also cases where drivers have still received basal skull fractures even while wearing one.

I don't know about you but I consider the Hutchens to be a cash extraction device since it is apparently priced at about 10 times what it costs to manufacture and they are vigorously attempting to get competitors to quit marketing similar setups (see below).

Personallly I prefer Jay Wright's approach to the whole business although his device is apparently not quite as effective as the HANS or ISAAC but it is more effective than the Hutchens:

http://www.over40racing.com/

Jay is a paraplegic NASA engineer who almost died when his car hit the T12 wall at Road Atlanta nearly head on during the Runoffs. His design is free to copy but you can purchase the materials from him if you wish.

Unfortunately he has just been approached by an attorney representing Hutchens to cease and desist because they believe it violates their sacred patent. A copy of the letter can be found on Jay's web site. Trying to get rich off of the collective suffering of drivers is reprehensible IMHO.

 

George:

Fancy meeting you here!

Thanks for the kind words, but we get this all the time. Fatbillybob is making some good points, but to us they are marketing issues that do not relate to the product’s performance. There is always a group of customers who will make their purchase decision based on the established history of an older design concept. That’s fine—I do it myself sometimes.

It is interesting that more Isaac systems have probably been sold in the first few months of its availability than were HANS devices in its first few years.

“I'll probably go a different directions for my own reasons…” Ouch. Are you sure we can’t talk you into a free rental?

I’ll attempt to answer any question I can, time permitting.

As far as dissing goes, fatbillybob is being relatively kind. I occasionally find myself on a forum (our web server tells us from where the hits are coming) that sounds like a HANS revival meeting, and the attacks have been vicous. If you want some amusing reading, I can e-mail you the links.

Thanks again.

 

[QUOTE]Originally posted by Paul Foster
Paul:


Actually, the data have been updated annually, but the articles are archived and must be purchased from the paper. The revised death count to date (approximately) is 300.



That was precisely our objective: a product that works as well, if not better, than the best device out there, but can be brought to the racer at a reduced cost.



This is true. No product is perfect, including ours. Any product will expand the window of survivability but can cause secondary injuries, i.e. it saved your life but it broke your (insert body part).



If we could make our product on a sewing machine, the costs would be much lower.

Jay is a good guy. We frequently tell budget racers that if they can’t afford an Isaac, they should buy Jay’s design. It is cheaper and works at least as well as other webbing designs. They can always upgrade later.

We deal a lot with patent lawyers. Speaking as an engineer, I don’t believe Hutchens has a snowball’s chance on a warm beach in a court of law. Patents are a necessary evil when you spend a wad on R&D, but the Hutchens patent strikes me as being very thin.

 

A question regarding mounting:

On the ISAAC website, it looks as though the shock absorbers are mounted to the lower part of the seat headrest. Is the seat drilled to accomplish this? If you have an aluminum racing seat, I see no issues. If you have a composite racing seat (a la Recaro, Sparco and others), then there may be a problem with using the ISAAC. Since the manufacturers of the seats have not tested the seat with a series of holes near the base of the head rest, I doubt that they would say that the seat was safe with the ISAAC hardware attached.

 

Doesn't mount to the seat. Mounts to the belts:

 

Just my $.02: I purchased a "demonstrator" ISAAC system a few weeks ago to save a few dollars. It arrived in its own carrying case with each part sealed in a plastic bag. I would swear they sent me a new system. I plan to mount it to my helmet this weekend and use it at the NASA event at Nelson in two weeks. Anyone in the Dayton area is welcome to stop by to see it or meet me at Nelson. The design, machining, and workmanship is first rate in my opinion.

 

Hehe. Yeah, I don't have a life. Perhaps that's why my car isn't done yet. (actually not true, but hey, if I don't laugh at me, everyone else will )

Actually, I don't have a problem with questions. It's more the tone really.

Well...... since you asked.

1) I have a new G-Force helmet and am strongly considering their restraint. I mainly am concerned that the belts will actually lock it in place properly. I'll have to see how the belts/seat/belt mount all line up.

2) Well, the HANS is the original. It's really etched in my brain.

3). Honestly, if the Isaac were offered in a yoke type design secured by the belts (as with the Hans and G-Force) where the yoke goes with the helmet, I'd probably be all over it. I'm sure you're selling what you've got as fast as you can make them, but this is something to think about. I'm just not sure I'd like my helmet strapped to the belts.

Or.... here's a brain storm. Perhaps if you can create a QR for the helmet pins that are pulled when the belt latch is undone, I might like that actually.

I'm sure. Actually, from all the restraints I've seen, I get the gut feel yours is the most engineered besides (or perhaps along with) the HANS. Many just look thrown together to me.

 

Geo / Gbaker:

No Disrespect intended. Just read the words. There is no "tone" there. You are reading more into it than is there. If I was out to disrespect someone I would not beat around the bush. I do not write "politically correct" I am lucky enough to get out a cogent thought with only a few spelling errors.

I am trying to understand these systems with very limited knowledge I.E. physics 101 and limited data from manufacturers of such devices. Personally, once you get beyond the crash sled study which is a specific way of looking at a specific crash you have to see how something works in real conditions. It is like your seatbelts....if you leave them in a box they are fine. One year in the sun on the racetrack and add in some sweet and oil you get 50% reduction in belt strength! There may be virtue and altruism in some devices presented but there is also marketing and someone having to make a buck. Many an outstanding engineer have lost control of their products by the time they went to market. The FDA recalls them all the time....People get hurt. I am thankful to engineer Gbaker for presenting us information on the ISSAC that isn't marketing hype.

The quick release idea should be taken seriously. I did not mention that issue but if you try to get out of your car in a fire I think I would hit my harness release then proceed to hang myself with my ISSAC . Is that an issue or does it come off really easy?


Someone else mentioned the Wright restraint. I had questions about that too. There is a seat belt bucke thing at the base of the neck in the void between the helmet and the seat. That is a quick release thing. In rear impacts the spine and body and seat streatch in all kinds of funny ways. I can see that buckle helpping to break your neck. Eng. Wright does not think that is an issue. I have only seen pictures of his device but it sure looks like a potential problem. Crash dynamics are extremely violent. The eye port clips are secured by silicone. What happens if one comes off and two remain? The whip action can result in very bad circular torque on the head and neck. The Wayne state crash sled was in one direction and very controled. I do not think there are any tests with angular moments.


Finally, I think the G-force restraint is flawed. There is huge room for user error in the design. There is also no company data to absolutely tell you where to position it. Therefore, I see huge variations as the SAE paper suggests in the G-loads to the head.

So far the ISSAC and HANS look like the best choices and best engineered. HANS takes into account the driver seat position i.e. reclined vs. upright. Does the ISSAC take this into account too?

 

Sounds like you read the article in SportsCar. Without hijacking this thread too much, that's BS. SFI is selling us a bill of goods and the SCCA is swallowing it. BTW, SFI is funded and run by the manufacturers. The data interpretation is flawed.

Oh man. EXCELLENT point. Hadn't thought of that. Thanks for pointing it out. Saves me from making a bad purchase.