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Re: Air Bag information from SCCA

To: "John J. Stimson-III" <john@harlie.idsfa.net>
Subject: Re: Air Bag information from SCCA
From: Kevin Stevens <autox@pursued-with.net>
Date: Fri, 19 Nov 2004 12:06:55 -0800
On Nov 19, 2004, at 11:11, John J. Stimson-III wrote:

> On Fri, Nov 19, 2004 at 01:27:28PM -0500, John Kelly wrote:
>> While the above is only a recomendation at this time, I have to ask 
>> what
>> happens to anybody whose face is exposed to the air bag "safety" 
>> device
>> during a collision?
>
> An airbag is designed to distribute the force of impact across a wide
> area, which reduces the maximum amount of pressure your body/head are
> exposed to.  It's still going to smart -- there may be "rug-burns" or
> bruises, but it's not going to break anything.

Not true, there are many, many reports of broken noses, cheekbones; 
and, most scary, glasses.

> A helmet is designed to do the same thing for just your head.
> However, it won't distribute the force across as wide an area as the
> air bag would, because it contacts the front of your head over a
> smaller area.  I think the concern in this case is that the force from
> the air bag pushes the helmet up and back, and it's the contact point
> between the chin-guard and your jaw that resists most of that force.
> That would tend to concentrate the pressure on your jaw rather than
> allowing it to be distributed across your face.
>
> In the case of the combination of a full face helmet with an airbag,
> the helmet defeats the function of the airbag, and concentrates the
> force rather than spreading it.

Yeah...  I'll stick with the helmet.  You know, the device designed to 
protect my face against high-speed impact with objects.

>> Does this study include what happens to a person wearing an 
>> "open-face"
>> helmet?
>
> Since the concern seems to be contact between the chin bar and the
> jaw, the problem in question could not happen with an open-face
> helmet.  It would be effectively the same as the case with no helmet.

Nice side-step.  Ok, did the study include what happens to a person not 
wearing a helmet?  (No, because it was targeted at F1 drivers, and not 
wearing helmets isn't an option.)

>
>> I'm having difficulty resolving how a "study" done in Formula 1 cars
>> relates to sedans.
>
> Are the air bags in F1 cars fundamentally different from those in
> passenger cars?

Yes.

>   What is there about a passenger car that would alter
> the outcome?

Force, speed of deployment, impact speed design of the bag, belt 
design, distance and alignment of the head to the wheel...

> You put "study" in quotes, as if you don't believe the research was
> valid.  Is there a reason to doubt the motives or methods of the
> authors?

Certainly.  They were studying another subject entirely, and probably 
had no idea that their (5-year old) finding would be extrapolated and 
applied to a significantly different scenario.

There's a bunch of reaction to this on the national lists, if you want 
to discuss it there.

KeS






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