Jack667

I recently bought a HANS device and I'm thinking of replacing my SRD drivers seat with the Recaro HANS seat.


It seems like a good choice, consistent with the "system" approach. Not sure if anyone has any comments on this approach. I have a Safety Devices cage and a driver window net for Club Racing, so I think the other gap, as identified onthis thread is the right-side net. I'll have to check that out...

Jack667

What about sliders? I have Recaro race sliders for my SRD's, mainly bc my wife and I share the car. When I upgrade to the new seta, should I dirtch the sliders? I think that my wife and I could come up with a compromise seating position that would be one or two positions forward for me and one or two back for her. This would also make the seat-back brace issue easier to deal with. Currently, I have it poisitioned rearward for my seating position, which leaves a gap when she moves the seat forward. I was planning to address this with an additional position on the adjustable brace that I purchased, or to add a foam insert to close the gap. Any comments would be appreciated. Thanks!!!

924RACR

As alluded to in another thread about seats, I'm not too fond of the upper restraint type exemplified by the Recaro HANS seat shown above. The reason why is that only the head would be supported in a lateral/oblique hit - the shoulder bolsters would only be supportive in normal driving, not in an impact. At very least, you ought to add additional, properly positioned shoulder bracing.

WHY is it taking seat manufacturers so long to catch up with this stuff? Why does it seem like the American Aluminum seat manufacturers are ahead of the Europeans on this? Why, God, Why?!?!?!!

DAR951

The Kiwi's too... Check out these (the "Viper" model) at the North American site of Racetech: http://www.racetech-na.com/products/4009/rt4009hrv.html

924RACR

Yeah, I've looked at it - but all their other seats are just like the Recaro pictured above, or less. No reasonably affordable solutions yet - only the US manufacturers are not in the stratosphere.

JCP911S

Adam... great stuff.. I think the key is to think system, system, system... so many guys put stuff in their cars and don't think about exactly what that equipment is supposed to do and how... and more important... what it is not supposed to do...projecting accident scenarios, and how your safety equipment would work... while unpleasant to do maybe... is a good thing

I believe that piecemeal use of safety equipment can actually reduce safety... though I have no data to prove it... but I see alot of DE students installing 5-points with stock seats...the belts frequently cannot be positioned properly or tightened properly...I'm coming to the conlusion that this is worse than using the factory three-points that at least have been crash tested by competent engineers.... especially in the newer cars with pre-tensioning belts and airbags... aslo they have belt bars or trusses behind them... I believe two piece seats are liable to break in a hard rear impact... having all that metal back there cannot be a good thing

There are so many things that can happen... I broke my hand two years ago... head-on into a tire wall... and I reach for the grab handle on the door... dumb, dumb, dumb instructor habit... fortunately I just caught my little finger... painful... but tolerable.... if I had gotten my entire hand in there, I probably would have shattered my wrist... so how you behave also matters...

Finally, extraction is an issue, but I have yet to see a car catch fire... not that it doesn't happen... but its alot easier to get out if you are not injured.... I wouldn't let that stop use of an effective device.

RedlineMan

Great Stuff, Boys!

You will note that when you see the latest sled tests, you most often see an alloy "Full Containment" seat being used.

I'm not sure if the "memory" of a plastic seat is good or bad? In an offset hit, if the plastic seat twists and the body escapes the seat, then the seat returns to position before the body recoils back into it, this might create some potential danger. An alloy seat would not have the memory of plastic, but would be waiting for the torso to return and might offer a safer scenario.

I am also not sold on the ultimate toughness of plastic. It is important to distinguish between strength and toughness because there is a HUGE difference, and I don't think a lot of people are aware of it. A perfect example is 944 control arms. The early steel arms are not that strong, but they are tough. The forged alloy late arms are the opposite. they are incredibly strong, but ultimately not very tough.

If you biff something with a steel arm, you will bend it far easier than an alloy arm, but it is very likely you will still have 4 wheels on the car. If you biff an alloy arm, it will take more force to damage it, but when it goes it does so catastrophically. Steel=Tough. Forgings=Strong. Neither are necessarily both.

Like forged alloy, high tech FRP (fiber reinforced plastic) can take a lot of abuse, but when it fails it does so catastrophically (carbon fiber alone). The types of alloy used in seats are not of that ilk, and would not be likely to fail completely, just bend and give.
------------------------------------------------------------------------------------------
If you combine info from the Safety Solutions, HANS, and Isaac websites, you get some pretty good ideas for how this stuff works, why it works, and how to look at the System approach that is so important.



When I constructed my Head Retention fence, it did occur to me that the shoulder/torso retention would be the weak link. I might guess that this configuration without an H&N device might have the "potential" to be harmful. I might also assume that employing an H&N device with this head fence will largely mitigate any danger the migration of the torso out of the seat might induce.

I have been mulling H&N systems for a while. I had not really considered the HANS because of the price and the perception that it was clunky and restrictive. I had been looking at the harness type systems because of price.

I have had occasion to see friends using the Hutchens at DEs, and that had swung me away from considering them. They are certainly quite effective if you look at the test data, but they are not at all user friendly as it applies to our DE environment. Extremely fiddly, cumbersome, and difficult to install in the short period of time we often have, jumping in and out of cars and such. I had decided on the D-Cel because of the moderate price and the relative simplicity.

However, time and deeper "out-of-the-box" thought has swayed me back again to the beginning. It occurred to me that it might not be overly comfortable having a harness cinched up in my crotch all day long as I ran all over the place like instructors do. I imagine they need to be fairly snug in order not to have too much slack to be effective. Also, the manufacturers state they need to be replaced every 2-3 years. Suddenly, $325-400 every 2-3 years seems far less economical.

I had borrowed a buddies HANS for a tech session on safety equipment held at my shop a couple weeks ago. I decided to give it a go this afternoon. His hat is a bit tight for me, and he is WAAAAY smaller, but I must say that I have now decided on a HANS. It is good for "life," assuming no crashes. Replace the straps every couple years and you're good. $900 once compared to $$+$$+$$+$$.

I must say that I was impressed by the feel of it in the car as well. I had some minor pressure point issues on my upper chest, but that thing WORKS! Much more peripheral rotation than I expected. Slam yourself forward in the belts and you get a reaction identical to the sled test on their website. The head stays upright, only rotating just enough to engage the forehead, which then takes on much of the force, and your head flat doesn't move more than 3-4".

If I end up with a HANS, I WILL INDEED be consulting them about the other parts of my "SYSTEM."

Just my thoughts and observations. Working it out in my head. What's y'alls heads think?

Jerry Ljung

John,

My apologies to you and all who may have spent any time reading that post.

VR,

J

RedlineMan

Hey Jer;

Umm... Your post is a bit confusing, and your intent unclear. Rather "obscurely" written, which may be a large part of my confusion.

Are you simply venting against what you see a short track stupidity, or are you poking fun at this sincere discourse on our own personal safety?

If the former, well... it is what it is. It's NASCAR. WWF on Wheels. For the same reason some people go to hockey games to see fights, some people like to see wrecks. Personally, I'm emphatically not one of either.

If on the other hand your tongue is firmly placed in cheek, you might want to rethink your position, as if someone were to take offense and smack you in the mouth, you might bite it off!

Again, the chaotic cadence of your wording does not afford me a true idea of what your point is. If your note is simply a rant against NASCAR, well... I agree. If it is a poke at we who are thinking and sharing about keeping our "family" safe, I would implore you to REMOVE IT. It doesn't have any place here, and neither do you.

Do let us know which.

JCP911S

Couple random thoughs on HANS... I have been using for two years now

First, check the height of your belt bars... I originally had my belts coming in level with my shoulders.....the HANS will add about two inches to the height of your shoulders, so now the belts were angled up... this caused the HANS to rotate, and put the point of pressure right on my collarbone rather than flush against my chest... uncomfortable and very bad news in a serious collision. So I had to have a raised Belt bar welded onto the cage... $200 extra....

Also, I tend not to use it at DE as generally I cannot wear it in the students cars as the belts have to be "just so".... and clipping it on and off and putting it somewhere where I won't lose it is just annoying...but I'm rethinking that... first, the walls are just as hard in DE... and secondly, we have been increasing our emphasis on safely as part of the program... so I think something visible like H&N restraints really sets the tone for that message to the students...

My rant.... .... I think the PCA DE policies on safety equipment could be upgraded generally.... many of the requirements/conventions date back to the days when students were showing up with box stock 914 and 944 with street tires.... now we see even Green students with 300HP cars with suspensions and R tires... gees....

Also the rules should be more systematic.... although we have added an "equal restraints" policy... as I said above... piecemeal upgrades could be worse than nothing... we owe it to the students and ourselves to assure that the safety equipment upgrades are systematic and each approved configuration is safe in itself....

Let me throw out a question.... do you think just adding 5-points to the stock car increases or decreases the safety of the car? My opinion is that it is worse.... what do you all think?

RealRideRacing

Vaughn,
We have installed the Racetech seats in every single car one of our cars (IMSA GTU Mazda RX7, American Stockcar Challenge Monte Carlo, SCCA EP Mazda RX7, Honda CRX NASA H4). After a horrific tragedy in an American Stockcar Challenge race last year in which one of our drivers was fatally injured, we did some very in depth research on race seats.
Racetech provided us with loads of crash data and crash test videos, which we made available for a limited time at our website. Of all the seats on the market, only the Racetech is sled tested to any high G-Loads. This very expensive research was performed with the help of the Daimler Chrysler Corporation since these seats were destined for the Viper Comp Coupes. Racetech claims that their Viper seats are sled tested to withstand 42G's, about twice the FIA requirements, and significantly higher than any other seat manufacturer that we researched. Several other manufacturers offered seats of manufacturer claimed similar levels of protection (PPI, La Joie, Recaro SMG, etc) but we chose the Racetech seats because they were able to provide our team's engineer with the most amount of information. Keep in mind that most head and neck safety devices are not designed for side impact protection.
Here's a link to our previous post:
http://forums.realride.com/showthrea...=&threadid=250

Regards,
David
REALRIDE.COM RACING
http://www.RealRide.com

RedlineMan

David - Thanks for your learned input. Always welcome!

JC - I forgot to mention that one thing that came to mind is that the HANS would be the least cumbersome OUT of the car. Poof and it's off and out of the way. I also plan to get the quick release so I can take it off for instructing. I see it as far too problematic, as you suggest.

As for your safety equipment concerns, as you might guess, I have some thoughts. To all: These are just my thoughts, and are NOT cast in stone, so DON'T blow a gasket!

I think the main difficulty will be that - all "obvious" considerations aside - it will be far too easy to come up with knee-jerk propositions that upon further study only save the minority and penalize the majority. A slippery slope for sure.

What are the benefits of harnesses? I feel that they are really in essence a concentration booster. Not sliding around so bad, using lots of energy to hold yourself in? More energy to be devoted to concentration! Safety? Yeh... that too.

To use your example of the seat back splitting the harness off a driver's shoulders, what are the percentages of people that come out of shoulder straps? Is it high? Moderate? Rare? What are the numbers? If it happens in only a small percentage and only within a fairly specific scenario, then would we not be penalizing the vast majority who might benefit from having harnesses installed? If the numbers are high and the scenario broad, then it is something that truly needs to be addressed.

Short drivers are theoretically more vulnerable to this phenomenon since the belts are lower and necessarily spread wider to begin with. So... how short is too short? Taller drivers don't have to worry as much since the belts are higher up the seat back to start with, but what if their belts are too long? Will they stretch too far and result in the same scenario as the short guy? Too tall or too short a body or belt? How do you decide, and do the percentages suggest you need to? Do the driver's shoulders necessarily travel downward in all instances?

One item that seems to be shrouded in mystery and ignorance is the sternum strap. I may be wrong, but it seems to me that this simple device will mitigate ANY POSSIBILITY of a driver having the belts slip off. When I mention it in safety meetings, I'm met with blank stares and silence. Is anybody out there?

Now you've got the Race seat with Harness controversy. There are instructors that WILL NOT be getting in cars equipped like this if they do not also have a roll bar. The contention is that a 3-point belt will allow the body to slump, but a race seat with harness will not, and if the roof comes down it may squish the occupants. Eee Gads... we must legislate!

But... WHAT ARE THE PERCENTAGES?????

Do we again stand to punish the VAST majority of drivers that MIGHT have an incident to save the ABSOLUTELY INFINITESIMAL number that roll? How many of these rolls see signficant cabin alteration? If we in reality stand a far greater chance of being struck and killed by a 1959 VW Beetle, then where are we going here, and to what ultimate purpose???

I'm gona stick my nose in some doors and see what I can do to make sure that we dont get a bunch of looney liberal socialist garbage stuffed down our throats. If it gets to the point you can't smoke in your own house.... you know?

924RACR

Very good post, and no qualms against Racetech specifically, but did you install the Viper seats? At $1300-odd a pop? I don't see the same degree of restraint in even any other of their seats, as confirmed by an email reply from one of their engineers (asking about explicitly that problem).

No question, though, that the Viper seat seems to be one of if not the best out there. I understand that for future lateral impact testing at Wayne State they'll be using one of those seats, since it seems to be the only one up to the job.

Ah well, I just hope the situation with the seats will turn out like H+N devices; at first, there was only the HANS for big money; within a year of sufficient interest, there were many options designed for a range of budgets. I don't need to survive going sideways into a concrete retaining wall at 100mph, but I do want to have improved protection for something less dramatic than that.

924RACR

I hear ya there, John!

Some specific technical responses regarding race harnesses without race seats, and regarding sternum straps.

The most interesting thing about this whole impact phenomenon is that, at least in a head-on impact, the way the body moves/distorts is to actually bow _around_ the belts - imagine the weight of the arms pulling forward around the belts - such that the belt buckle is in a pit in the stomach. This would confirm that, in this case, a sternum strap is unnecessary to keep the belts together, since the body actually holds them together.

The sternum strap came from noticing in stock cars, with 5-pt harnesses, that some people were breaking the sternum. Speculation was that this was because of the body squeezing between the shoulder straps, so they added the sternum strap to try to prevent this. Turned out later, through further investigation, the broken sternum was caused by, IIRC, the use of a single-strap sub belt - circle track guys used the 5-point, whereas formula car guys have run 6-point belts for longer. This is my recollection, something odd like that. Anyway, the sternum strap was the solution to a problem that didn't exactly exist, or wasn't properly understood.

So, no help there from a sternum strap. One thing it CAN do, not in a positive way, is to slide up and injure the throat! Consider the belt stretch.

I bought mine with a sternum strap; after the Detroit Region SCCA presentation explaining the above, I left it unbuckled. When I re-webbed my belts this spring, I had the sternum strap removed.

As to how it could help you in a lateral impact or without a racing seat, I couldn't speculate. I have trouble picturing how it could help...

boqueron

JCP911S

"Let me throw out a question.... do you think just adding 5-points to the stock car increases or decreases the safety of the car? My opinion is that it is worse.... what do you all think?"

Why do you think it is worse ? Worse than the standard three point ?