Otto Mechanic

I'm trying to narrow down seat choices for a 944 and match them to a an H&N restraint system. Like lots of folks I'm building this car so I can drive it to the track. It's not a street car, but I also don't want to trailer it.

I'd pretty much convinced myself that the Sparco Ergo seats were my only choice if I wanted a HALO seat I could drive on the street, then discovered the new Simpson Hybrid H&N system. It looks like it works without HALO seats.

If that's true it opens up the field on seat selection. I haven't found anything that comes right out and says a HALO seat isn't necessary for lateral support using the Hybrid, but there's a lot of implication. Anyone know of real lateral crashes involving the Hybrid in a non-HALO seat? I'm not a ghoul or anything, I'd just like to know if this is a practical and effective configuration. I don't think any of the manufacturers are going to come right out and make recommendations on the subject so hearsay, experience and informed opinions are welcome.

ApexPerformance

Simpson has done third party testing with auto manufacturers in Detroit which was proven effective with a 3-point harness that is also FIA approved. Recommended for driving instructors, auto manufacturing testing engineers and autos with 3-point harnesses to have added protection. Simpson suggests for BEST protection, use a full containment cockpit system (full containment seat, snell helmet, fia/sfi head restraint and 7-point harness system). Basically you can use the hybrid with a stock seatbelt but Simpson claims for maximum protection, use a full containment system. If you are going to have a harness installed with shoulder belts, you can use the Hans or Necksgen as well. Again, both of these manufacturers recommend a complete containment system as well.

Circuit Motorsports

The lateral testing for all head restraints is done is at a 30 degree angle. Not a full on side impact 90 degrees. The halo is protecting you at that 90 degree impact.

z06801

Interesting, so is this something that might be effective even for jumping in a students right seat?

ApexPerformance

Yes - according to Simpson, this is the only thing on the market that will offer head & neck protection in a stock seatbelt.

Otto Mechanic

I think that answers my question, thanks. It's a little difficult to locate all of the claims made by the different designs.

Like any safety system, there are always ways to make things safer if you're willing to make other concessions. If it works at all on a standard seat with a 3 point belt, that's good to know.

Otto Mechanic

Maybe this is getting closer to the question I was asking.

Literature I've found on the Hybrid claims it offers lateral support by design. The tethers are independent with two on the back of the helmet and two on the sides, rather than a single tether behind the neck that slides when you turn your head. At least this is my understanding based on photos and description.

The theory is the Hybrid provides lateral support where the HANS doesn't, meaning the HANS depends on a containment/HALO seat for 90* lateral impacts while the Hybrid does not.

The question I'm really asking is, is that understanding correct? Certainly I would expect a HALO/containment seat to add some measure of safety through redundancy if nothing else and I wouldn't expect a manufacturer to make the claim that use of a Hybrid with a HALO seat wasn't, in some sense, "safer" than without one. Some folks wear a belt and suspenders.

Otto Mechanic

I suppose what I'm really asking is, is a HALO/containment seat necessary by design when using a Hybrid, as it is with a HANS?

Taken to extremes, safety can overwhelm engineering design. To give an absurd example, a driver might be "safer" in an injected foam pod with rocket assisted ejection than in a containment seat. You see where I'm going; I'd like to assess whether the safety benefits of a HALO + Hybrid design outweigh the disadvantages a HALO carries WRT limiting driver visibility and ease of egress.

ApexPerformance

To get the ideal safety, Simpson is suggesting the containment seat and all the other safety equipment as it all works together to protect the driver.

Unfortunately, each manufacturer claims their HNR outperforms the competition but no one openly shows testing results to back it up. SFI tests the tension on the neck (there's a minimum the HNR has to meet) and the FIA tests the structurability of the unit itself - they put it in a vice and pull on the tethers and measure how much force it takes before the unit breaks/cracks/fails.

The Hybrid is FIA only. Most Hans devices (except those with quick click helmet hardware) are SFI/FIA and Necksgen is SFI.

Circuit Motorsports

Yes, use a containment seat.

The HANS does offer a decrease in the numbers in the 30 degree offset impact. It just doesn't do as well as it does in the frontal impact. The Hybrid and Hybrid Pro have performed better in the offset impact numbers game than the HANS.

I've owned/been given to test out most every head restraint and currently race with the Hybrid Pro.

I do believe that a Halo seat increases the level of safety no matter what kind of device you are using. Look at NASCAR and Formula 1 where they are allowed to build a car around safety and not deal with the compromises of turning a street car into a track car. They have extensive head surrounds.

Otto Mechanic

I don't doubt it at all, as I mentioned earlier, a closed cell ejectable foam pod might also increase safety, however that might be considered over-engineering

What I'm really trying to explore is whether or not the Hybrid actually offers useable lateral support. Apparently the various manufacturers skirt this issue by only testing at the 30* angle of impact, which forces consumers to either reason vigorously, or depend on actual driving results.

I don't mean to argue or even ask someone else to argue that a HALO seat plus <fill in the blank> HNS system will probably be better than either component alone. The question is, "does the Hybrid actually provide significant lateral support?"

Otto Mechanic

The problem of course is in both parties understanding what "ideal safety" means. It would not behoove a safety equipment manufacturer to ever suggest a safety system they did not manufacture was unnecessary.

I'm sorry I neglected to mention I had already understood that point. It doesn't surprise me the manufacturer would suggest the systems would all work together to protect the driver, which essentially means the systems are compatible. That isn't quite the same as saying the combination is beneficial, only that it apparently isn't harmful.

Professor HANS

Someone posted: "Apparently the various manufacturers skirt this issue by only testing at the 30* angle of impact, which forces consumers to either reason vigorously, or depend on actual driving results."

Please note it is not the manufacturers who decide on the testing protocol, it is the sanctioning or homologation body, in this case the SFI. But actual results are a good thing to study - since mandating Frontal Head Restraints NASCAR has recorded a database of over 6,000 impacts with no serious head or neck injury. That's a pretty good testament to the safety systems they use - which include a full containment seat.

Why are side impacts hard to quantify? An adult neck breaks at about 900 lbs. of force. Let's say a 90 degree side impact loads the neck to 3,000 lbs. Now, lets say testing shows a frontal head restraint reduces this load 50% - so the force is reduced to 1,500 lbs. Remember 900 lbs. is the threshold for a fatal injury. It would not be prudent to advertise "works in side impacts" would it, even though it does. How about "reduces side impacts 50%" - Is this valuable information that allows you to make an informed choice? No it's not, it's misleading as it overlooks the fact that the device does not lower the forces enough to be effective.

You may find old ads for Hybrid FHRs claiming side impact protection, but more recent tests have resulted in new information recognizing these devices are designed for impacts up to 30 degrees offset, and a full containment seat or side nets (a very good, inexpensive alternative) are required for protection in side impacts beyond this angle.

To summarize:
FRONTAL HEAD RESTRAINTS AND SIDE IMPACTS

1. All FIA and SFI certified frontal head restraints offer protection from zero to 30 degrees offset. No FHR provides complete protection in side impacts beyond 30 degrees. For complete side impact protection head surrounds, full containment seats or side nets should be your primary means of protection.

2. What defines side impact? If you mean someone hitting your door at 90 degrees but the manufacturer means slightly offset from head on you are not talking about the same thing and you may not receive the level of protection you expect.

3. Anecdotal evidence shows lateral head surrounds, full containment seats or side nets must be used to provide protection from side impacts; while your frontal head restraint provides protection from zero to thirty degree offset impacts.

4. The Simpson 360 degree approach to cockpit safety - harness, helmet, suit, seat, nets and head restraint has been proven to provide exceptional levels of safety in your race car.

Thank you for the opportunity of posting in this forum. Please do not hesitate to contact me directly for information on cockpit safety.

Gary Milgrom
HANS Performance Products
gmilgrom (at) teamsimpson (dot) com

Otto Mechanic

That was something I wrote and it was based on statements made in a review of H&N restraint systems that indicated the testing protocols were originally determined by the inventors of the HANS device, who were also largely responsible for writing the SFI standard used in device certification. Is it incorrect? Some device manufacturers have commented in literature that no standard for lateral shear measurement exists within the automobile safety device industry and have expressed some (possibly cynical) views on the subject. I'm only repeating what I've read, I hope you'll understand I'm not the source nor am I in any way affiliated with any company that manufactures or markets H&N restraint systems. I'm a retired engineer who once specialized in reliability modeling so I have some background in statistics and experiment design in an industrial setting.

Which leads to my confusion when you beg the question "why are side impacts hard to quantify?", then go on to quantify them? On the subject of reducing lateral shear, certainly a 50% reduction in lateral force is valuable, regardless of whether it protects the user against all risks? After all, no safety device could accomplish that?

After reading the SAE comparisons it would appear the most effective device currently on the market is the ISAAC system, and that company does in fact make quantitative claims with respect to lateral shear force reduction using their equipment (coincidentally they claim a 50% reduction), so I would think it would be in the best interest of other companies to make performance data on their devices public as well?

Otto Mechanic

BTW Gary, I do appreciate your weighing in on this and I also understand you don't set policy or control the SAE. I recognize your name from several of the technical publications I've read on the subject and would like to personally thank you for the effort you've put into making this sport as safe as possible. I would imagine it's gratifying to know your work has saved so many lives.