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Author Topic: Home-made head restraint  (Read 4141 times)
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RebekahsZ
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« on: December 26, 2017, 11:04:55 PM »

I'm trying to pass tech to 200mph at ECTA in my (soon-to-be turbo-LSx) 240z.  I have tried to fit racing seats with shoulder bolsters into the car in the past, and due to the narrow confines of the car, I would wind up chopping a store-bought seat up in order to get it in the car.

So, I'm trying to modify a Kirkey Intermediate Drag seat in order to pass tech (and protect my head!) with a completely bolt-on head bolster.  ECTA rule book requires lateral helmet restraint over 175mph, but does not describe the specifics of how that must be accomplished.  I don't want to use a funny-car cage, because I plan to return this car to road course duty after going 200mph in the standing mile. 

Attached are some pictures of a preliminary cardboard mock-up of a home-made head bolster. I still need to make lower gussets, which will be angled up and forward from tabs on main hoop of the cage in order to provide both lateral stiffness and vertical load stiffness.  The upper gusset will attach to tabs on the cage as well.

Questions:
1.  Is the head bolster high enough?  (I hope so, because a gusset on my main hoop makes going any higher difficult)
2.  The back of my helmet is 3 inches away from the headrest in my driving position.  How long does each leg of the bolster need to be, relative to my helmet? (I have made them 16.5" on each side, hoping I can cut them down some-getting in and out around this thing is gonna be a challenge!)
3.  Why are there no ECTA or SCTA bail-out drill videos on youtube?

Keith


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manta22
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« Reply #1 on: December 27, 2017, 11:56:14 AM »

Keith;

You have raised a very good point. Lateral head restraints are required but whether they are a blessing or curse is debatable. In theory, they are a good idea- keeping your head from being thrown sideways in a wreck therefore injuring the skull/spinal column joint.
Limiting head movement by a restraint that is fixed to the roll cage is dependent on the driver's shoulders staying fixed relative to the roll cage & head restraint. If the head is restrained but the shoulders move, the same injury will occur. A "full containment" seat with attached head restraints should work fine but not all car types can accommodate one of that type.
It seems to me that a better alternative is possible- if the now-required HANS were modified to add high bolsters on its shoulders, the lateral head restraint would automatically be referenced solidly to a driver's shoulders. This would be completely independent on the seat design and would not hinder getting in or out of the vehicle.
It would take the safety manufacturers' to design and test this concept to conform to appropriate safety requirements but I think it is possible.
I realize that the object of the head restraint is to protect a driver in case of a severe accident but, on the other hand, a restraint should not kill him by keeping his head fixed while his body moves or by hindering his quick exit in the case of a fire.

Regards, Neil  Tucson, AZ
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Regards, Neil  Tucson, AZ
Elmo Rodge
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« Reply #2 on: December 27, 2017, 08:43:18 PM »

On that note, I put shoulder bolsters in my car because of that.  wink
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Stainless1
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« Reply #3 on: December 27, 2017, 09:12:40 PM »


So, I'm trying to modify a Kirkey Intermediate Drag seat in order to pass tech (and protect my head!) with a completely bolt-on head bolster.  ECTA rule book requires lateral helmet restraint over 175mph, but does not describe the specifics of how that must be accomplished.  I don't want to use a funny-car cage, because I plan to return this car to road course duty after going 200mph in the standing mile. 

Attached are some pictures of a preliminary cardboard mock-up of a home-made head bolster. I still need to make lower gussets, which will be angled up and forward from tabs on main hoop of the cage in order to provide both lateral stiffness and vertical load stiffness.  The upper gusset will attach to tabs on the cage as well.

Questions:
1.  Is the head bolster high enough?  (I hope so, because a gusset on my main hoop makes going any higher difficult)
2.  The back of my helmet is 3 inches away from the headrest in my driving position.  How long does each leg of the bolster need to be, relative to my helmet? (I have made them 16.5" on each side, hoping I can cut them down some-getting in and out around this thing is gonna be a challenge!)
3.  Why are there no ECTA or SCTA bail-out drill videos on youtube?

Keith


Keith
1.  The lateral restraint should be about ear to temple level... so your head is supported if you slam it to the side.  Your pic looked about right.   You must be restrained in your seat... if you can slide out of your seat, your head restraint will injure you.
 
2.  3 inches to the headrest is outside the rule... 2 inches is the max listed to the pad... the lateral have to extend the forward most part of the helmet... yep this is the part that makes getting in and out of most cars a pain.

3.  Not sure how watching someone else struggle will help you....  rolleyes
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Stainless
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RebekahsZ
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« Reply #4 on: December 28, 2017, 12:26:33 AM »

Thinking about racing my wife’s minivan-it has a tall, wide, sliding door. Lots of room for safety equipment. I guess if it was easy, the staging lanes would be longer....

I will try to post a bailout video to be the first. Watching folks struggle let’s me know what “reasonable” looks like.
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RebekahsZ
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« Reply #5 on: January 01, 2018, 04:49:58 PM »

So, here's the mock-up I've made in craftshop foamboard.  To exit, the left bolster will telescope off and get put on the floor after pulling a pin.  Then the door net gets dropped and tossed out the door opening and I start wriggling my fat butt out.  Still too afraid (of my steering wheel coming off in flight) to installl a steering wheel quick-release, but that would sure help.


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RebekahsZ
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« Reply #6 on: January 01, 2018, 04:55:41 PM »

Thanks to everybody who has replied, and to those who have sent me messages.  Per the discussions above, after I have the head restraint done, I will work on a right shoulder restraint.  There is absolutely no room for a shoulder restraint on the left side of the car; however, my door bar is at the level of my shoulder, and I will SFI pad that, and it will function as a left shoulder restraint.
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jacksoni
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« Reply #7 on: January 03, 2018, 07:17:00 PM »

That is slick but... you have just rolled the car and dinged it and the pin wont come out and your arm is dinged as well. Can you get out? Car is on fire and the rescue folks are a minute away? Not trying to be smart a$$. I had a fire at speed once. Took a long darned time before help rolled up.  It wouldn't take much for you not to be able to get the sliding part out. The rules that put the helmet support so far forward really does make it tough. In my car the space is tight so same issues. With helmet on and Hans, things can hang or just be tight to get forward enough to get out more or less same way you get in, at least for me. I do have steering wheel release. I feel is mandatory, can't get in out with wheel in place.  Bail out was hit switches, fire bottles, seat belts and window net, pull steering wheel, open door, swing feet out first and slither out on my back/butt. They give you 45 seconds. I did it under 10. Much faster than trying to lean forward and going out sideways head first with the helmet/hans.  Don't know if would work for you but an idea.

I would certainly run your design past the car chief inspector or Lee Kennedy before cutting metal. Good luck.
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RebekahsZ
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« Reply #8 on: January 04, 2018, 04:03:14 PM »

It seems like the populace is split on the issue of the head restraint.  But, the rulebook seems pretty clear.  From observation of the tech line, some inspectors are more by the book than others.  In fact, I have taken the car thru tech on Friday and gotten one list of faults; then gone thru the tech line on Sat and gotten an entirely different list of faults.  Fortunately, the faults being found are minor, since I do try really hard to have no faults whatsoever, and I have never been denied the opportunity to race.  I have also found that tech inspectors lose track of which organization they are teching for, and might remark about faults that pertain to the wrong track/organization.  But I've never been "dick-ed over" by an inspector.  I have found that they are just trying to keep us safe so we can go back to work on Monday.  I'm gonna build it to keep me in the car.  I've never seen a car that was perfect-one can always make an argument for improvement.  The pins and aluminum arrived today.  Will try to post some progress photos over the weekend.
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manta22
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« Reply #9 on: January 04, 2018, 06:19:07 PM »

I am a firm believer in the idea of the head restraint's being an integral part of a HANS device. A HANS works to restrain the head's motion fore & aft; why not side-to-side as well?

Regards, Neil  Tucson, AZ
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Regards, Neil  Tucson, AZ
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« Reply #10 on: January 04, 2018, 08:58:23 PM »

 Hi Keith, I have a little bit of experience bailing out of a Z. I would suggest you be able to get out of the car without having to pull the pin on your side piece. I like the idea but you need to be able to get out without having to worry about pulling the pin. In our car my Hans device would get hung up on the ISP pieces and I had to make sure I scooted forward and bent my head forward to get out. I practiced quite a bit so i was fine with the bailout. Also put on your firesuit,belts, gloves,helmet and arm restraints when practicing. Its totally different than doing it in street clothes. Good Luck, Be safe.

 Gary   Dcwaterjet Z
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Gary Cole     DCWATERJET Z
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« Reply #11 on: January 06, 2018, 02:51:28 AM »

Looks like a good design. I have seen a few where the pin would be in shear from a crash force. But yours has the shear load being reacted within the square tube. You didn’t mention the direction of pin pull. If it is pulling up, from the top, that could be a problem. I saw a design last year that had a push-pin inserted from the bottom and was removed by pulling down. A much faster and easier operation when seated down low.

The spec for the steering wheel release is SFI 42.1. The spec is a well-engineered test criterion. It also requires fireproof materials.  I suggest you read the spec to satisfy some of your doubts. Not only is egress faster and safer than any stock apparatus, but the mechanism is most likely more robust than anything you have in the car now.

Thanks for the post and the pics . . . it is a very important rule but is a packaging problem for many cars.
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« Reply #12 on: January 23, 2018, 03:55:41 PM »

I did as Gary said above.  I would get a good quality steering wheel release.  I can't even get my legs out without removing the steering wheel.  I pop the wheel out of the way, drop the door net and come crawling out head first.
 
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RebekahsZ
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« Reply #13 on: January 26, 2018, 02:39:56 PM »

Here's what I have made so far.  Heading out to shop to make fore progress.


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RebekahsZ
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« Reply #14 on: January 26, 2018, 02:41:15 PM »

And from the rear.


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