Hans Question

[tlracing]

I believe the reason that lateral impact has the greater potential to cause damage is because it can induce rotation to the brain stem, as the majority of the skull is forward of the spine. Direct forwad/backward motion is less likely to result in rotation.

I first bought my HANS device as I was racing in the USA, in a category where it is obligatory. It came from Hubbard-Downing, who I found extemely helpful. Properly set up, I didn't even notice it was on; the only time it made me aware of it was putting on/taking off my helmet.

Nothing is going to stop brain movement relative to the skull it's in - but a HANS device can reduce the degree and speed of skull/helmet rotation. That being so, simple Newtonian maths suggests it will also reduce the momentum of the brain inside the skull and, thus, reduce the potential for brain stem trauma.

[ss_collins]

Originally Posted by tlracing

I believe the reason that lateral impact has the greater potential to cause damage is because it can induce rotation to the brain stem, as the majority of the skull is forward of the spine. Direct forwad/backward motion is less likely to result in rotation

Its not just brain stem - as the rally side impact research done by cranfield proved (see RCEV16N2). As I say there is no clear evidence that Hans is really beneficial in any type of shunt other than the type it was designed for - there will be a design limit depending on angle speed and type of impact where the hans ceases its usefulness, but this information is not easy to come by - is it because all the research was funded by hans makers?

It does certainly protect the brain stem however. but what are its wider implications?

[fangio]

The talk about HANS seats or a HANS set of belts is rubbish; they can be used with any homologated seat or harness as long as you fit them right.
Having a high seat when you're small and the belts go through the seat higher than your shoulders is wrong; even if you don't use the HANS device. It will allow you to move up in an accident and with the acceleration you could easily damage your spine.
The same goes for the belts; if you find that your belts slide off the HANS, they are not correctly fitted.

Only last week I saw the latest video's at Stand 21 of the various tests - I'm convinced....(I was convinced already)
The first time I used the HANS just by coincidence I put a modern saloon car head on into a guradrail. I felt very lucky having used the HANS.

I use the HANS both in modern (LMES/Le Mans etc) and historic racing. I don't think there is a reason not to use it in Historics, apart from certain open cars and cars that don't have roll-cages and belts.

However, I strongly believe that everybody has the right to get himself killed if he wants to........so the 2008 rule that they must be worn in ALL FIA Championships (incl. historics) is wrong.
I guess that's to get the figures higher - not for the suppliers but for the FIA that collects money for every HANS anchor fitted to a helmet, because the anchor now has to have the FIA logo and a sticker.................

[Eddy V]

Correct fangio, the "Hans compatible" slogan seems to be the thing every manufacturer of belts and seats (and maybe soon even for gloves ) uses.

We "tested" an 10 year old seat a few weeks ago with the system: fitted like a glove. Hans compatible? Noooo.
We compared a certain modern saloon seat, non complient, with a near perfect copy, complient. The difference: two bigger holes in the back for the belts.

Who is fooling who here?

[greenamex2]

The lateral impact stuff is interesting.

Why aren't the FIA mandating 'seats with ears' or something similar?

I've got one, it was about £50 more than a normal one and doesn't impede me at all.

Is it because Formula 1 already has head side impact protection so nobody has bothered?

[Al Weyman]

What ever they are doing in F1 is certainly working as you don't see many deaths or serious injuries these days thank God. Or should that be thank the technicians?

[Suze]

That's HANS though, that's only been brought in in last few seasons. F1 has a lot more safety improved through cars, cell structure and circuit safety as well.

[JimW]

Originally Posted by ss_collins

. . . as the rally side impact research done by cranfield proved (see RCEV16N2). . . .

Say what?

Jim

[ss_collins]

Racecar Engineering Volume 16 No. 2 (Feb 06).

We published some research by Cranfield University on rally car side impacts, conduucted shortly before Beef's shunt, pointing out the problems and suggesting some solutions.

[JimW]

Thanks, I'll follow that up.

Regards

Jim

[M100MSA]

I posted earlier in this thread and will again point out that we have a vested interest in Hans as we are re-sellers. To help with some of the comments here I have added a whole host of links to our website at:

http://www.msar-safety.com/index.php?main_page=index (then click on links)

There are a number of .pdf files there but the most important is the Harness Users Guide. To get to the point the Hans is only as good as the harness holding it and the harness is only effective if it is fitted properly. Using a Hans will show up a poorly fitted harness very quickly and I would say that for this alone trying a Hans is a good idea. My own experiences across a number of historic racing cars are pretty telling.

1: A 1960's car that had belts attached to roll cage about 24" below my shoulder line, result a very uncomfortable drive and lots of pressure, the tendency was to run with loose belts. The fix was nothing more than relocating the mountings.

2: A 1970 car that has mountings about as far apart as your shoulders are wide, the result here was belts that literally came off, not very useful at all. This time there was rather more work involved but relocating the mounting points was the solution.

I dont accept that "historics" are a problem per se although fitting any equipment to an older car needs some thought. I use the device succesfully in historics, I have not had to buy a "Hans specific" seat and as the posts are supplied with the Hans it was a simple matter of getting the helmet drilled, which by the way is done FOC by re-sellers, whether me GPR or anyone else.

As I have replaced my harnesses I have opted to use Hans specific harnesses but that has been through choice and normal wear and tear.

The device does not have a service life and will easily last a decade, there are no known intentions to give the item a service life but I dont speak for the MSA, FIA etc of course.

Finally the issue of price, as I sell these things I get to see the numbers, the Hans is the least profitable thing I deal with. Sorry but I dont see anyone making a killing here, it really is a very low volume item that carries a lot of cost. The margins on a £500 handbag are at least 4 times better than the margins on a Hans................

Once again I can say that I will happy answer any questions any one may have, preferably by email.

Thanks

[greenamex2]

Nice site M100MSA.

You are just round the corner to me, are you open of a weekend?

Do you (or anyone) have any access to crash simulation data? The document link on the site refers to 40G, is this realistic for a typical saloon car?

[RickP:Clio51]

Read Stand 21's promotional material on
http://www.stand21.fr/tour%20auto/tour%20auto-2.html

then click on the slightly mispelt box at the bottom "owners manual" which links you to Downing/Hubbards research and includes the testing data and in particular the photographs from Mercedes Benz crash tests with the neck load information.

This should answer a lot of questions.

[greenamex2]

Originally Posted by RickP:Clio51

Read Stand 21's promotional material on
http://www.stand21.fr/tour%20auto/tour%20auto-2.html

then click on the slightly mispelt box at the bottom "owners manual" which links you to Downing/Hubbards research and includes the testing data and in particular the photographs from Mercedes Benz crash tests with the neck load information.

This should answer a lot of questions.

Yep, already read all that several times over and it raises the same question the 'skeptics' have been asking continuously.

How relevant are the tests to out world?

The documentation details just enough to sound scientific but not enough to allow intelligent people to decide if the test situation is relevant to them.

So, I repeat and rephrase my previous question, am I ever likely to experience a 45G acceleration in my tin worm infested 70's designed saloon car hitting a typical solid object on a British circuit?

Having driven into various objects at speeds far greater than the documented 35MPH and not even having the slightest neck ache, let alone neck injury, I know that I am not experiencing the 45-50G that the gee whizz brochures document from their tests.

Note that I am not debunking their tests, they all are very reasonable and realistic figures, but the relevance of them.

[ss_collins]

What would be nice to see is the original USAF data

[Red Baron]

Originally Posted by ss_collins

Racecar Engineering Volume 16 No. 2 (Feb 06).

.

Sam,
I've looked at RCE V16 No2 on the net and without subscribing I can only see the MIRA Crash Test article that could be the one you refer to. Is that the one?

I'll have a look for the mag in the shops tomorrow but I don't think it's main stream so I may have missed it. WIll we be able to read the article (or at least the gist of it) anywhere else?

Rosie

[Teletubby]

RickP51

Fortunately I wasn't one of the doctors/marshalls that had to attend to these scenes. U might like the right to kill yourselves and your family might bless you for that but there are others affected, sometimes traumatically.

Sadly, I and several others on this thread have attended incidents such as these and frankly I wouldn't wish the experience on anybody.

My view is that this device has been designed and tested by people with degrees in Bio-Mechanical Engineering, those tests have been validated by other, independent, testing athorities and the FIA have approved and even mandated the device for some series.

I would rather take that data and evidence as proof of the effectiveness of the HANS over the views of some conspiracy theorists who suggest that this is a simply a licence to print money!

Sure the device doesn't save lives in every instance, nor does a crash helmet but it does help to reduce the occurrance of devastating injuries. If BSF is so rare how come I have attended three accidents in as many years where the driver has suffered this injury?

I don't believe that mandating the use of the HANS device is the right way to go but I do think that it is worthy of serious consideration, easy for me to say as I don't need to buy one!

For those drivers reading this thread and thinking "Do I, don't I?" then please consider the evidence in support with rather more conviction than the theories that are being put up against by laymen.

[greenamex2]

That's the point Teletubby, nobody is presenting any evidence relevant to the club saloon driver!

All we are getting is some advertising bumpf with no real details of the tests and their relevance to us. If anyone believes a sled running into a solid wall at 30 odd MPH relevant then they nothing about physics.

A look through all the endorsements also reveals very little scientific evidence.

I would have thought a bunch of people with degrees in bio mechanics could knock up some estimated G readings in an impact for a saloon car in their tea break, maybe they just can't be bothered as they realise the FIA/MSA etc
will just mandate HANS at some point anyway.

If you have any real life examples, please share them (with some details) that is all I am asking.

[Red Baron]

Why do you think that the evidence Teletubby refers to is not relevant to the club saloon driver. Just becasue you are travelling at speeds slower than an F1 car does not make you immune to BSF and other injuries.

I know, becasue I was there, that at least two of the incidents Teletubby refers to were club saloon drivers. What more evidence do you need!!

Regards,
Rosie

[greenamex2]

Originally Posted by Red Baron

Why do you think that the evidence Teletubby refers to is not relevant to the club saloon driver. Just becasue you are travelling at speeds slower than an F1 car does not make you immune to BSF and other injuries.

I know, becasue I was there, that at least two of the incidents Teletubby refers to were club saloon drivers. What more evidence do you need!!

Regards,
Rosie

I never at any point said that Teletubbies examples weren't relevant, I just asked what they were.

I said that the suppliers and manufacturers evidence MAY not be relevant and that nobody with any credibilty has ever actually stated that they are, and why.

That is why I asked for the examples.

If I believed everything that everybody told me without questioning it, starting with loony religous sects and ending with every single advert on TV, I would be dead by now.

[Teletubby]

That's a fair comment Dennis, research has been carried out, as I said, by independent research organisations including the TRL in the UK.

All 3 of the incidents to which I referred involved club racers, I don't feel that it is appropriate to give details which could lead to identification of those incidents but suffice to say all 3 drivers suffered basal skull fractures after impacts and my opinion (for what it is worth as a layman) is that in two of those cases the HANS may well have prevented such a catastrophic injury.

Can I prove that? No I can't, it's an opinion but one that is backed up by scientific research as opposed to blind objection.

Consider this when thinking about the relevance to 'club racers'.
The pro's (many of whom are already using HANS) may spend vast sums of money on crash helmets which are produced from expensive materials and are very light weight (as well as exercising to strengthen neck muscles). Your average club racer cannot afford this every few years (or worse if the helmet gets damaged) so he/she will (hopefully) buy the best they can afford which will still be heavier than a very expensive helmet. If you strap a weight on top of your head and then drive around at 50 mph, when you come to an abrupt halt your head will carry on with this weight still attached to it, finally being restrained by your neck. This seems like a recipe for injuries. Now substitute 100mph for 50mph and the forces are more than doubled (not sure by how much, physics not a strong point of mine but I'm sure somebody will be along shortly to provide the calculations. JimW?).

HANS appropriate for club racers? Too right it is!

[greenamex2]

Originally Posted by Teletubby

That's a fair comment Dennis, research has been carried out, as I said, by independent research organisations including the TRL in the UK.

HANS appropriate for club racers? Too right it is!

Quoting the TRL as a reliable source of testing is never a good idea given some of the idiotic things they have tested and pushed for in the past that have then had to be withdrawn due to safety reasons.

However I get your point and am interested that there have been basal skull fracture related accidents in UK club level saloon car motorsport.

Unfortunately unless there are some real cases and technical data (something a bit better than on the sales websites) documented in something like the MSA newsletter then voluntary take up of the device is always going to be limited. If the MSA then force it on us, again without 'buying' support, then we will lose even more drivers.

I am still amazed that the vendors of these products are trying harder to get the message across.

I'm still going to order mine and am now, as a result of these discussions, slightly more positive now that it will be of possible benefit in certain situations.

I'll report back what it is like to wear, but hopefully never what it is like to rely on!

And the risk increases with the SQUARE of the speed, which is why all the questioning about relevance to my slow heavy saloon car!

[ss_collins]

sorry seem to have confused a few of you in V16N2 there is a piece on saloon / rally side impact and I'm also working on a piece on frontal impacts and where we are at. In earlier RE's there was quite a bit on HANS and the events leading to it but unfortunatley these issues are no longer available apart from second hand. V16N2 isn't in the shops anymore so you can only get a bcak issue online.

The broadley termed HANS piece is on the way as a follow up to the side impact stuff.

[JimW]

Originally Posted by Denis Bassom

. . .

And the risk increases with the SQUARE of the speed, which is why all the questioning about relevance to my slow heavy saloon car!

Well possibly.

There are a number of measures which could have significance when considering situations such as this. These may be easy to define in terms of basic physics but working out which ones define the mechanism of impact is much more difficult. From what I gather from discussions with an expert the "severity" of an accident (unfashionable term but you know what I mean) is, broadly speaking, proportional to the CUBE of the impact velocity.

But different injury mechanisms may involve different measures such as Impulse (PT), Momentum transfer (MV), Energy dissipation (0.5MV^2). Add in to this the way in which the human body reacts to different forces/accelerations over different times and the fact that different parts of the body react in different ways and you will see why there are no simple answers to this. And given that motorsport injuries are, statistically and economically speaking, tiny, then there is unlikely to be much research carried out. (It is hugely expensive.)

Look at the work on road cars and then consider that much race engineering is directed in precisely the opposite direction to road vehicle safety considerations. Race cars are engineered to have the maximum stiffness (you don't believe that roll cages are only designed to protect the driver do you?) while road cars are deliberately designed to crush over quite large distances in specific circumstances. This spreads the duration of the impact over a longer time and hence reduces the peak 'g' loading. But is does not change the energy or momentum involved.

Look at some of the HANS sites and note how the test results show that the chance of the head striking the steering wheel are much reduced.

Of course I am not suggesting that further work would not be very helpful, perhaps particularly with diagonal, sideways or twisting impacts.

A real understanding/exposition would require a good mechanical engineer with the right specialisms. (Probably a team of them.)

Like RedBaron and Teletubby I have been at a number of incidents (some of them the same ones) where, on the face of it, a HANS would have been a very positive thing. Equally I have seen cases where it would have been irrelevant. This sort of open forum is not suitable for discussions of detail and cases because of the risk of offence, but my experience, reading and discussions with experts of all sorts certainly makes me think that the HANS is likely to be a big net contributor to safety in many circumstances.

Regards

Jim

Reference http://journals.pepublishing.com/link.asp?id=76412k08117652qq (Abstract only, but it references the cube law I quote above.)

[Al Weyman]

I am not an advocate of Hans because of the excessive costs involved having said that surely Dennis your Toyota would hit what, 125 mph + down the back straight of Thruxton or Snetterton I know for a fact my older Camaro did 156mph down the Thruxton straight and with what 150 bhp more and weighing about 150 kgs lighter and a far more slippery shape the Black car I reckon would hit 175mph at Thruxton if I have the bottle to hold my foot in (debatable). Now that sure must be fast enough to do a heap of damage to my old neck so I would say the speed argument is a little irrelevant unless we are talking 2CV!