924Board.org

[924RACR]

Just wanted to pass on some observations and discussion notes to you guys...

I talked yesterday AM with Gregg Baker, an engineer at ISAAC, the company that makes my head+neck restraint system (www.isaacdirect.com). He brought up an ITA CRX that had a similar, but much harder, lateral impact into a concrete retaining wall at Road Atlanta, driver's-side first. The impact was so hard it put the driveshaft into the concrete!!! Yow!

Oh, yeah - the driver was wearing an ISAAC device. He suffered no spinal trauma or the like. As I recall, he had some other bruising, and bit his tongue, so saying he got off without injury would not be correct, but all the stuff did its job!

But we were discussing the options available to help for side impact. I still feel (based on discussions and review of crash footage with those in the business) that passenger-side impacts are, to some extent, the worst way to hit a wall, since the driver can be thrown over that way, and in a sedan there's little usually over there to restrain you. When the driver's side hits, the side of the car, door bars, and window net are close by, providing much sooner, better support.

Note that being t-boned is a different case.

Anyway, the discussions I had with Gregg focused on two main items; the seat and other internal restraints. #1, the seat, well I've got a Kirkey, which is generally agreed to not be the best. The support is great for driving, but it's not going to help in an impact, as it's not strong enough, and it doesn't restrain the shoulders (which are more important to restrain than the ribs) at all. A proper FIA-certified seat with shoulder supports would seem to be an improvement.

But I'm still struggling with this one, and with the expected cost of a new seat ($400+ at least), I'd want to buy once and get the Right Thing for sure! Problem is, there doesn't seem to be a huge consensus on exactly what is needed in the seat design to do the job. It's also possible that the seat will need additional external bracing - I dunno.

Next month, at our Waterford Hills meeting, there's supposed to be a race safety engineer from GM present; I plan to attend and pester him with such questions.

Currently, I'm leaning towards a seat which is getting a lot of positive attention from the community with regards to lateral impact safety, the Racetech seats (from New Zealand). They start at $390, and go up to $1400 or so. The only thing I have not established yet is the relative level of safety provided in the low-end vs. the high-end model. Here's their website for you to peruse.
http://www.racetech-na.com/start.html
http://www.racetech.co.nz/ (New Zealand site)

Their high-end seat was selected for use in the Dodge Viper Competition Coupe as standard equipment.

The odd thing to me is that their low-end seat, though a little cheaper than others, doesn't really seem to provide noticeably more shoulder lateral support than, say, a basic OMP, Momo, or Sparco. So that's why I'm wondering if it's only the $1400 seat that is really good for side impacts.

Then the "other" restraints. The primary item here, and the most in-use by the pros in sedan racing, is the "auxiliary" internal restraint net. I just picked one up from RJS when I got my belts re-webbed - $45 or so. It's designed to be mounted more or less on the centerline of the car, next to the seat, so that it'll catch you when you lean over to the right. It comes with a seat-belt buckle type release, so it can be moved out of the way in the case that you need to exit out the right side. This usage is most commonly seen in NASCAR cars - just watch the in-car shots. It's positioned to catch the upper body - shoulders and head.

It will also, if properly positioned, provide the function in an oblique frontal impact, of guiding the driver BACK into his correct seating position when rebounding from belt stretch. Naturally this would mean that it would be right up against the outside of the right shoulder support of the seat. Otherwise, the driver could rebound and be caught in the middle of the back by the seat sides, depending on the g-levels reached, the amount of belt stretch, and the seat design used. As might be expected, rebould could be pretty bad with a Kirkey, at least my type, with very big rib bolsters.

Just some thoughts to pass on and get you guys thinking about racing safety... I'll pass on further info as I get it...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[wdb]

my knowledge of all this stuff is limited , but what are the top speeds on the tracks you'll likely attend . I mean if your not likely to exceed 100 mph ever , do you really need the extra protection from the top of the line safty equip. or is it just a cushion from there perfect senario test results . I'm a firm believer in, its better to be safe than sorry . its better to have it, and not need it ,than to need it, and not have it , I would have , I should have , I could have , but I didnt .

you being an mech. engineer ,in the auto industry , couldnt you get your hands on some inertia tables (sliderule kinda stuff) ,and contact the suppliers and compare what youll likely see in the real world to thier test figures and parameters for thier seats and other equiptment . personally , I dont believe a word anyone says when it comes to my life exspectancy, especially salesmen and brochures .theres to many real world examples of phd's. doctors , scientist, making simple but critical errors . double check everything , just to be sure there's wasnt any errors that could cause problems . because , ultimately , its my own fault ,if anything goes bad , because I didnt investigate fully .

[ryoji]

You can find a test result of "Head and Neck Support" systems at HANS, Hatchens or others. Or at the site of NASCAR, SCCA etc. Most of the results show the impact of 45G~55G, which I think is from 35MPH~40MPH. All shows the significant defferences with and without suppor systgem on the head and neck. Somebody told me that the impact is too big to measure on 100MPH for the current measuring equipments in a dummy.

It is hardly believe that there would be an accident on the streight; however, my data logger showed 115MPH at the end of back streight of the Glen and 108MHP at the front streight of the Summit Point, last time out.

In order protect myself, I need a kind of these systems as well as basic and other extras. You never know when and where I get into a trouble.

From a club organizer point of view, I think they want to have much protective equipment enforce to racers as possible(acceptable in vareity of reasons).
_________________
R.I.P.:a 924 ITA race car

[AndyFranklin]

The Safety Symposium at the SCCA National Convention really pushed the use of the interior net. Particularly as it is a very cheap addition to the car.

As a flagger I have some questions about them having to do with access, since the passenger side is generally the side we try to use. (It is generally the side away from traffic, if yu wondered why.)

It makes the location of the kill switch pretty crucial. Without the net I can reach any switch in any location. That might not be the case with a net. Hopefully I'll get the chance to play with netted cars in the paddock before too long.

I know we will be stressing the use of the nets at both the Comp Clinic (Mar 20) and Safety Day (Apr 24). Mark your calendars!

[jjadczak]

Thanks Vaughan, for taking the time to put this together! I've been in a wreck with the Kirkey seat that Vaughan has and it didn't move a bit and I was really confident about it's ability to hold my ass. I am going to think about the shoulder and head restraints that Kirkey now sells because we've already bought two brand new seats for our cars. I also like the net that I'm seeing in these NASCAR's. THis is something that I'm very concerned with after being in 2 crashes. I did look into the HANS device, and I'm just starting to look into other devices because my bfather has also been talking about it. Thanks again for starting this discussion.

Jeremy

[924RACR]

Sure thing. Having also been a flagger, I also appreciate the concern about kill switch access. That's why I have 2, one on each side of the car; the main one inside the driver's window, which I can reach and do use; the other one under the hood by the battery, accessible by a pull strap that sticks out at the base of the windshield.

The interior net is not that big a deal; it's released with the standard GM-style belt buckle, easy enough to hit, just like the driver's side window net.

Bad news from Racetech, though... I emailed them, got a reply back from the NZ headquarters, which basically said you need to buy the top-of-the-line seat for big bucks to get anything more than the typical support (as seen in OMP, Momo, Sparco, etc) for lateral impacts. I will probably get a cheaper, FIA-cert. Racetech seat at some point, so that others can actually fit in and drive my car, and they're still quite affordable, but no real major upgrade there, I think, for lateral hits. Unless the change from supporting the ribcage to the shoulder is a major upgrade... certainly is an improvement.

Here's the text of his email, for reference...

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

Hello Vaughan and thanks for the enquiry through our distributor.

You are correct in seeing the real benefits of the Viper seat. We had Dr
John Melvin give us the brief for this seat and the expected lateral loads
which can be expected in a 45G impact.

The beam and back mounting is unique in the world to our Viper seats and our
new model (9109HR) which has just been approved by the FIA. The shoulders
are also very square which supports the shoulder area well in an impact. In
a male most of the body mass is in the shoulder. These seats also have
energy absorbing foam in the vital areas hence protecting the body and
reducing the initial shock.

The theory behind a good seat is that 4 areas must be supported well and
kept in the same relationship to each other.

The thigh , Pelvis , shoulder and Head. A seat should not support the Ribs
as there is no protection with muscle and the vital organs are right behind
the ribs.

Our previous models of seats with side Head restraint are still better than
no head restraint but when these were designed the current technology was
not available.

I trust this helps in your decision making process and if we can be of any
more assistance please let us know.

Regards

David Black
Managing Director
Racetech Seats
New Zealand
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[wdb]

924RACR . I came across some inertia tables , I have no idea how accurate or useful they might be , but thought you might be interested .

http://not2fast.wryday.com/chassis/sae1999-01-1336.pdf

I saw them here at drive train and suspension .

http://not2fast.wryday.com/

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