Sean F

One more thing to note, you will need a seat back brace and it looks like one isn't being used in the photo. My net wraps around to the vertical portion of the main hoop by the drivers B pillar but it was a little tricky to do getting around the large seat back brace.

Larry Herman

Sean, not with that seat. PCA allows you to run an FIA seat (less than 6 years old) without a seat back brace.

Sean F

Good point Larry. I thought NASA didn't have that carve out, but they do.

Phokaioglaukos

I've put a call into Joe Marko at HMSMotorsports to hear what he thinks. That's a good idea. Who is there to talk with at BRS on this?

I'm pretty sure the net in the photo is wrapping around the seat and connected to the cage, but I'm not sure exactly how. In a converastion last night a Racetech rep suggested the head restraint seat and no right-side net. Somehow it seems that having both would be good.

Larry raises an interesting point--if the seat breaks free or moves (which it really should not) attaching the net to the seat would allow there to be slack in the net that there would not be were the net not attached to the seat. That slack would allow more movement to the center of the car than otherwise. Of course if the seat is not attached to the floor, or has broken, then I suppose there is likely to be unanticipated movement of the driver all over the interior.

I did have a conversation with Joe Marko last year about seat back braces. He told me that to be useful and not unsafe the pad that fits up against the seat back had to be really large (like 15"-20" diagonal) and that there were no commercial versions available like that. My GT3 seats in the Porsche are mounted on the OEM seat rails and I do have to move the seat for different drivers and for use on track on and on street, so I bagged the idea of a seat brace for use in DEs. For the race car the seat will be permanently fixed to the floor and reinforced. Using a seat that meets and is mounted in accordance with FIA standard 8855-1999 or higher does not require a seat back brace under SCCA GCR 9.4.1(B). The inexepensive aluminum seats do require a support to the main hoop of the cage. Sean, do you have a FIA seat AND a brace? Do you have photos of your installation you can share?

Sean F

My system is: custom seat rails structure on the floor welded to the sill and the tunnel, Recaro SPG seat, Brey Krause seat back brace and BSR quick release net attached to the cage and a custom fabbed bracket through the radio slot. I'll see if I can get some pictures today. I will be doing some tweaking to my system this winter. My net is too low, partially due to my seat being so low with the custom rails on the floor and because I went to a better net that became available after we did the work. I'm going to create a new attachment point coming through the air vent over the radio slot or through the top of the dash.

BTW, John Hajny aka RedlineMan built my system so if you have questions about the seat rails he built give him a shout. Custom fabbed seat rails make a big difference in my opinion (and his).

Larry Herman

Chris, I actually meant that the net wraps around the seat, and goes behind it perpendicularly and attaches to the main hoop on the left door pillar. It would act as a sling that way, with some give, but little lateral movement unless the seat moved forward, thus allowing slack in the net. One disadvantage in this arangement is that it would require re-adjustemnt if you moved the seat fore or aft.

Sean F

I have to say that I find it frustrating that there really isn't a good source of information on this stuff. I realize there are liability issues all over the place, but I would love it if PCA had a safety expert that had a clear mandate to review all the available research on safety and issue clear guidelines. Not necessarily new rules but helpful information on how to design a safety system. It just doesn't make sense that each one of us has to go out and track this stuff down. Not to mention the fact that every cage builder, installer, race shop has a different point of view. This should be one area where the club should be much more active than we are right now (for DE and racing). Maybe the thing to do is put aside an annual budget to hire a consultant to conduct an annual safety review and produce a white paper on constructing safety systems.

chancecasey

I think the issue is that unlike mass-produced cars, the amateur racing community has limited crash testing data available. You get a few really hard impacts a year and usually it's with some different combination of all the factors involved - a particular car with some particular cage, seat, net, driver weight, speed of impact, type of impact, other car in the impact, etc.

e.g. - whether the side net is connected at the A-pillar or straight back, the first will cradle better but stretch more. what's more important in various impacts? We all know that ideally stretch is matched to impact, but since we don't have systems to lengthen/shorten webbing in anticipation of X amount of g-force impact, we have to compromise and usually design for the *harder* impact. In this one little variable of the side net, it's hard to say which rear attachment is better without having several cases of seats coming flying off with both net configurations and trying to interpret the results.

Usually of the combination of many of the important factors is unique to that particular impact. One data point per combo makes it all but impossible to draw a lot of sound scientific conclusions, so you're left with taking what little you DO know, and then trying to connect the dots. Most guys aren't willing to definitively say "this way for sure" when the reality is it's an educated guess.

However, all that being said, I think it would be GREAT GREAT GREAT if someone would at least compile after-impact pictures, with accounts of what happened (speed, other car, situation), weight of driver/cars, how the various bits (like side nets) were configured, and how the driver fared. I think that would be of good use to everyone, but it's no small task.

RedlineMan

Hey;

Were your ears burning? This has been on my mind for a LONG time. Since I am in the middle of all this stuff, and since I have studied it intently for the past few years, I have had the same exact feelings. It is ENORMOUSLY frustrating to see all the missinformation and missunderstanding out there. My friend's (all of you) safety is at stake.

I have been trying to get something rolling with PCA for a long time now, but have had virtually NO success whatsoever. I have sort of given up, to be honest.

I even have a document substantially underway that adresses ALL of the equipment decisions you might encounter. As you might imagine, it has been a TON of work, and is VERY difficult to write.

I can tell you all EXACTLY how a side net should be configured, even though that point alone would take many hundreds of words and a few diagrams.

Sean, for the record, I was NEVER EVEN CLOSE to happy with the net in your car, and really regretted the damn thing immensely. Part of that was that the net itself was just not right. I'm glad you are pursuing a better one (the Safety Solutions 3-strap?), and would be willing to help in any way I can. You paid good money, but did not get its worth regarding that stinkin side net!!!

Sean F

John, I started a new thread to get some ideas out on this - you should post in it.

Thanks for the offer on the net. I do have a much better net to work with now. The original would never have worked right. I'll give you a call over the winter for some advice on the next install.

Phokaioglaukos

From another site comes this advice:

Read the following SAE paper on interior nets and their proper installation:

2004-01-3513
Race Car Nets for the Control
of Neck Forces in Side Impacts

The net-net (pun intended!) is that the upper strand HAS to run along side the CG of your helmet/head or the net can actually do more damage than good. Any lower, and in a side impact it can stop your shoulder but not your head, causing your neck to stretch even MORE than without a net. Too high, and it'll be pushing on the top of your head, causing "unhealthy" compression in your neck and spine. Remember, safety equipment has to be installed properly or it can cause more problems than it solves.

And this:

The net has three strands in back. The top strand goes to the the hoop and the middle to the harness bar. The bottom one wraps around behind the seat and attaches close to the foot of the hoop by the door. Use shaft collars to keep the strands in place on the cage tubes. The front strand attaches to the stock bar buried in the dash right behind the two center vents.

gbaker

You should publish that, John. There are very few people such as yourself, who put the total package together.

RedlineMan

Thanks, My Friend;

You more than anyone can appreciate the gravity, and difficulty, of such a task. I'd need a real pro to vet my work!

RedlineMan

Let me pick at this a bit;

You can try and support/retain the head in two ways. 1) By choosing a height of the tip of your nose, halos/side nets will not restrict your side vision, but will be more or less placed at the center or gravity of you head. Anything lower or higher - by itself - will create a point that the head will roll over/under. 2) you can also restrain the head by catching both the upper portion of the helmet (above the eye line), and the jaw area. This would be what I refer to as a "window seat," or net that you look through, not over.



Either way is effective in the abstract. The problem is the linearity and the direction of travel of the body.

The whole thing starts to fall apart when you get into real crashes because the directions of motion involved are so variable. Sled testing tells you what happens at that direction of motion, not every real crash. You can design optimally for the test, but trying to cover every real eventuality is virtually impossible.

You can hit something and be thrown at any angle under the sun. No system can counter every angle that might be seen. The best you can do is make the equipment work for a straight horizontal impact, and hope that any crashes fall within a comfortable margin therein.

Indeed a 3-strap net (like the Safety Solutions model) seems to offer the most versatility in mounting, and coverage in occupant retention. One strap at head height, one at shoulder height, and one to corale the seat. However, given the forces involved, I'm not sure I would trust a simple shaft collar to do the work of holding things in place.

Most people who use shaft collars opt for the nylon variety. These are mostly seen in use to keep shoulder belts from sliding along belt bars. I suppose the use of a metal variety would increase the clamping force sufficiently to keep them on place. However, I have some concern that this does not enter linear loads into the belt at the mount, and as to what this will do to the belt matrerial?

I think it is far better to create dedicated hard point mounts for each terminus, just like you do with the lap and shoulder belts. Like this one I did for Sean's upper side net mount.



A standard belt end plate goes into this mount. About as bullet proof and reliable as you can get, and tested and known to work effectively. I'm not sure how a looped belt reacts to being stretched into/over a collar?

Minutia, indeed, but also proof that this is not a no brainer add-on!

Maytag

All; Excuse me for resuscitating an old thread, but this seems the most appropriate place for my questions.

I've just jumped into the Spec Boxster world, with a very clean, prepped car. The current seat is a Halo seat that is too narrow for me, and expired anyway; so I'm shopping for a replacement.

I've got lots of HPDE experience, and many years of Superbike racing in my youth, so I'm no stranger to racing, But I've never spent any "real time" in a race car. I have some fears about feeling claustrophobic in the car, wearing a race suit, gloves, HAANS device, etc, but I'm sure I'll acclimate. But the HALO seat has me sort of quaking in my boots, haha. Climbing into and out of the car is pretty difficult for me right now, even in shorts without a helmet on. I'm sure there's a "trick" I'll get figured-out eventually, but part of the difficulty is clearly that halo protrusion on the existing seat. I think climbing into and out of this car would be MUCH more simple without that; which brings me to safety. If I can't get out of the car, how safe IS it?

Having read this thread, and countless other sources, I'm just as confused as I was at the beginning of my search. :sigh:
I'm hoping that with more years of use and experience with the Halo seats, and further refinement of the products, that perhaps there has formed a consensus on the matter?

So to put a fine point on it: IS a HALO seat more safe to a degree that makes it worth the additional difficulty of getting out of the car, and the lower visibility while racing? OR is there a balance between a Non-Halo seat and a right-side net that gets us a better balance?

Thanks in advance.