Backrest angle / HANS device / fuel cell

[JJLudemann]

Solidworks is telling me the slope of the off-the-shelf ATL 7.5 gallon wedge fuel cell is 51 degrees from vertical. Is that a reasonable angle for the backrest so the two can fit together? What do other cars use? The reason I ask is that HANS devices only go up to a 40 degree angle, and I read somewhere that a lot of people return the 40* model in exchange for a 30* model. Also, what angle of HANS device do F1000 people typically use?



-Jim

[glenn cooper]

Hi JJ, I currently have a Model 20 that I have used in about everything.
I have tried a 30 in my RFR F1000, and it works better.
In my last car, a converted VD RF99, Jim Downing himself said the model 20 was fine.
It depends on many things, mostly how tall the driver is, and therefore how reclined the seat can be made w/o the driver smashing their knees into the dash hoop.
Most folks use a 30 in cars like ours. I think a 40 is more for IRL cars.

[rickb99]

Solidworks is telling me the slope of the off-the-shelf ATL 7.5 gallon wedge fuel cell is 51 degrees from vertical. Is that a reasonable angle for the backrest so the two can fit together? What do other cars use? The reason I ask is that HANS devices only go up to a 40 degree angle, and I read somewhere that a lot of people return the 40* model in exchange for a 30* model. Also, what angle of HANS device do F1000 people typically use? -Jim

In most formula cars with the Fuel cell directly behind the bulkhead that is behind the driver the sheet metal does follow the contour of the fuel cell. That provides the most possible room in the cockpit. But that angle usually ends about 9" to 12" off the cockput floor when it reaches the top of the cell and runs in to rear cockpit cross bracing.

In fact, your driver will not be at that angle. Idealy, you'll be pouring a bead seat behind and under the driver for his comfort and safety! That will be a big factor in determing his reclined angle and which HANS angle is correct for each driver.

Typical U.S. drivers are in the range of 5'10" to 6'3" tall. With the way most of todays formula cars are built it's difficult to get them in to a super reclined position. Yes, I'd say most are using the HANS 20 or 30. Our driver is 6'2" and due to the cockpit/foot well length limitations in the Reynard is in a somewhat upright position with a bead seat behind him. He uses a HANS 30 but I think a 20 would be a better fit.

The determining factor on the HANS angle is getting the proper clearance from the HANS to the back of the helmet.

[JJLudemann]

Glenn, it's great to hear Jim Downing referred to as "Jim Downing himself". I was attending races and my sister was racing against him more than 20 years ago when he was working on the prototype, and I only recently found out he's considered the father of the HANS device. Engineers don't get enough credit. By the way, my partner & I loved your story about "Poooosh, Giancarlo, eet eez time to poooosh!"

Rick, thanks, that's the magic piece of information I was missing-- the backrest has*two* angles, one for the lower section and one for the upper section. I can see it now when I look carefully at a photo of a Citation that was posted here a couple of years ago, which I've attached. So does the top section typically go fully vertical, or what?

-Jim

[rickb99]

.....photo of a Citation that was posted here a couple of years ago, which I've attached. So does the top section typically go fully vertical, or what? -Jim

That photo (except for the massive qty of rivets used which has always impressed me) is a typical example of the rear bulkhead/fuel cell cover in any formula car.

No, usually not totally vertical. Depends upon the design of your roll bar and bracing. But more like a 15 to 20 degree rearward angle is probably 'typical'. Remember there is another critical HANS issue once you get up into that area. You need 'several' optional (in the vertical plane) shoulder harness attachment points to properly attach the shoulder straps for the HANS.

When we had ours modified for the HANS we had the fabricator install 2 vertical bars properly spaced apart (spec'd in the HANS info) with 3 optional, sleeved mounting bung holes in the vertical plane to accomodate different height drivers.

Example, our drivers shoulders stick up about 5" to 6" above the top edge of the fuel cell enclosure. So we ended up using the middle of the 3 vertical mounting holes for the shoulder harness's.

[Wren]

That photo (except for the massive qty of rivets used which has always impressed me) is a typical example of the rear bulkhead/fuel cell cover in any formula car.

You just have to get in the groove. When Brandon was building his plane I think there was one night where we banged 700-1000 rivets in a few hours. The dimpling and other prep work had already been done, so the riveting was easy.

[JohnPaul]

I plan on ordering my Hans this week, I'm 5'11" , 200 elbows in an Elan VD DP04 (same as the FE car) which do I purchase 20 or 30? thanks,
JP

[kea]

With you sitting in the car, have someone measure the angle of your upper chest (where a HANS would sit), in degrees back from vertical. Even for some racers who sit quite vertical (nascar), if they have a large chest, might come up with numbers that may require them to wear a 30 degree, over the more common (for their type vehicle) 20 degree.

[Richard Dziak]

John Paul:

Wearing a Hans 30 in the Phoenix F1K.07 Formula F1000.

Perhaps you can find a few fellow racers who have a Hans 20 and 30 so that you may try one of them one in your car seated. Be sure that you are comfortable and your neck, back and shoulders have a comfortable angle, otherwise, if you get the wrong Hans device angle you may find it very uncomfortable to wear. A proper angle and fit with this device is very important.

I had a former IRL driver in New Mexico tell me that a improperly fit Hans may cause more injury than driving without one.

Be sure you get the right fit for safety and comfort.

[iamuwere]

Most everyone is wearing a 30d in FE that I have seen. My 30 feels pretty good.

[cooleyjb]

In almost every car I've sat in the 30 was the better choice. I think a Standard FM was the only one that I can remember that the 20 would have been comfortable for me.

There are also options that aren't seat angle specific as well like the Safety Solutions Hybrid Pro

http://www.safetysolutionsracing.com...-pro-rage.html

Here's a great resource for head restraints.

http://www.racesafetydata.info

And a compilation of sled test results for them

http://www.racesafetydata.info/HNR.html

[problemchild]

I just had a customer buy the Hybrid Pro HNR as Joe linked above. He is a tight fit in a laydown FV. He just put it on between sessions and used it. No mods to car, seat, or belts. Very impressive! He went much faster immediately after putting it on .... which was coincidental but shows that there was no impairment to his comfort, focus, or performance.

[JohnPaul]

Saferacer.com has the Hans sport for $545 which is cheap but they also have the "Pro" for $1000+, besides the weight difference (1lb) is there anything else that'll convince me to spend double? and is 1 lb that much or a difference?

also, when ordering it asks to select tether and anchor types?? this is more difficult than buying a car.....

[Richard Dziak]

Most likely the $545 Hans will do the job. Your helmet will need anchors installed. Anchors are priced at about $65.00 and about $50.00 to have them professionally installed. It is an easy task to DIY or you can send in your helmet and have the anchors professionally installed, as they require a measurement from the back and bottom of the helmet. If you DIY be sure to use a smaller drill bit to drill into the helmet first, once you make a mistake, you can't change the drill holes and you don't want to mess up an expensive helmet. There is quick release tethers that you will need to decide whether you want to pay the extra for those.

I did the install my own anchors on 2 different helmets without any problems, and I use the what I call the manual release tethers, rather than the rip cord quick release tethers. I am sure others will have input here for you.

This is a sport where you will find that you can always upgrade and spend more bucks $$$ for items and upgrades that may not make a difference in your style of racing.

Deciding what to spend $545 vs. $1000 is a personal decison.

Seems like your getting closer to running your new car. Get ready for some real thrills and enjoyment. Your doing the right thing by asking lots of questions.

[JohnPaul]

Seems like your getting closer to running your new car. Get ready for some real thrills and enjoyment. Your doing the right thing by asking lots of questions.

Yes, I'm doing my drivers school in 2 weeks at Sebring. Brett Lane has been helping me a ton to get the care ready. We are bringing it over to James Lee's shop this week so he can go through the entire car and give it a proper set up.
I've been asking a ton of questions so I can learn as much as possible and don't make any expensive mistakes. Everyone here on this forum have been great, so helpful and genuine about it. I'm really happy that I've decided on the FB class

[cooleyjb]

Saferacer.com has the Hans sport for $545 which is cheap but they also have the "Pro" for $1000+, besides the weight difference (1lb) is there anything else that'll convince me to spend double? and is 1 lb that much or a difference?

also, when ordering it asks to select tether and anchor types?? this is more difficult than buying a car.....

That 545 is misleading. That's for the youth version. The second you select the adult size it jumps up to the same price as everyone else has. Noone is allowed to advertise a lower price than retail for a HANS.

As for anchors I'm a fan of the original post style. I don't like the ones that are permanently attached.

As for Sport vs. Pro. The weight is not noticeable once you have it on in the car. The only dimensional difference between the two is the lip on the Sport is a little more pronounced.

I'd check in with Keith Averill if I were buying a HANS.

[iamuwere]

I definitely think the traditional style HANS anchors are the best type, but that is my opinion. I do not feel the "quick release" with the clips with the "rip cords" are worth the trouble. Very easy to clip the traditional post by yourself even buckled in a formula car.

[JohnPaul]

[quote]

That 545 is misleading. That's for the youth version. The second you select the adult size it jumps up to the same price as everyone else has. Noone is allowed to advertise a lower price than retail for a HANS.

you are very right, as soon as I put in large and selected the tether and anchors, the price jumped to $665 and $695''

I think that is very expensive for what it is, a molded piece of plastic and some straps (please no comments trying to justifiy it), I was orignally looking at the DefNder but had alot of people that didn't like it. What else is out there that is as good (or better) and not out to make a killing on every one.

[Matt King]

I was orignally looking at the DefNder but had alot of people that didn't like it.

Maybe you should try one yourself before you dismiss it as an option. Could be you won't share the opinion of those who don't like it.

[cooleyjb]

[QUOTE=JohnPaul;260605]

you are very right, as soon as I put in large and selected the tether and anchors, the price jumped to $665 and $695''

I think that is very expensive for what it is, a molded piece of plastic and some straps (please no comments trying to justifiy it), I was orignally looking at the DefNder but had alot of people that didn't like it. What else is out there that is as good (or better) and not out to make a killing on every one.

John,

I carry the DefNder and the Hybrid Pro and have used the HANS in the past.

The issue that most formula people have had with the DefNder is that the part that comes over the shoulders and down the chest sits a bit higher than the HANS and in the reclined position of a car like the DP04 the bottom of the helmet might contact it and you can't look down to the gauges. This is happens often with people who are barrel chested or have short necks. I have a shorter neck and was right on the cusp where the contact caused issues.

The Hybrid Pro is the one I currently use. It accomplishes the head restraint with a different design so nothing is coming over the shoulder. The device sits on the upper back of the driver and some straps come around the chest and down to the lap belt. It is the most comfortable device I've used, although I've never really noticed any of them after I've turned the car on. It comes from a line of 3 different devices that all do the same thing with slight differences in design. The most obvious difference is how far down the back they extend. The R3 and the Hybrid go further down the back than the Hybrid Pro and use chest straps to maintain stability. The Hybrid Pro transfers it's forces down to the lap belt.

As for good/better/best. I think all the devices are very good, some are better than others according to the testing numbers. For those we have to rely in many cases on what the manufacturers release from the testing they are required to do to meet the applicable standards of SFI. Most of the devices do very well in the 0 degree frontal impacts. The differences start to appear in the offset impacts (not side impacts but from a 30 degree angle). While all the restraints we've talked about decrease the forces your neck goes through, some do it better than others. The HANS numbers in the 30 degree impacts while very much down from a non-restrained test are nearly twice what they are in a frontal impact. The Hybrid series of devices have nearly the same numbers in the 0 and 30 degree impacts.

The difference in numbers, or lack thereof, between the 0 degreee and offset impacts are the main reason I'm using the Hybrid Pro right now. I just have a feeling that when I do have a meeting with an object that doesn't want to move it won't be straight in and those offset numbers will be more important. Plus I can get out of one car and jump in another without changing devices as the Hybrid Pro is not seating position specific.

[JohnPaul]

Maybe you should try one yourself before you dismiss it as an option. Could be you won't share the opinion of those who don't like it.

I would but that would mean I'd have to buy one to try it. I don't know anyone that has one.

[JJLudemann]

[quote=cooleyjb;260607]

The Hybrid Pro is the one I currently use. It accomplishes the head restraint with a different design so nothing is coming over the shoulder. The device sits on the upper back of the driver and some straps come around the chest and down to the lap belt... The Hybrid Pro transfers it's forces down to the lap belt.

I've been looking at the Hybrid Pro design, and yes, it transfers the forces down to the the lap belt when those forces really should go into the shoulder belts. The result will be compression of the spine, and sure enough, in the success story on their website the driver suffered two fractured vertebrae and four compressed discs. And I'm going to take a wild stab and guess that the fractures were compression fractures:

http://www.safetysolutionsracing.com...my-r-3-sa.html

I wish I was wrong about this (for the lawyers: this post represents my opinions only). I hate to disparage someone's product, but this is a matter of life and death. It may take several years before the verdict becomes clear, but in the meantime I know which design my vertebrae are asking for.

-Jim

[cooleyjb]

I've been looking at the Hybrid Pro design, and yes, it transfers the forces down to the the lap belt when those forces really should go into the shoulder belts. The result will be compression of the spine, and sure enough, in the success story on their website the driver suffered two fractured vertebrae and four compressed discs. And I'm going to take a wild stab and guess that the fractures were compression fractures:

http://www.safetysolutionsracing.com...my-r-3-sa.html

I wish I was wrong about this (for the lawyers: this post represents my opinions only). I hate to disparage someone's product, but this is a matter of life and death. It may take several years before the verdict becomes clear, but in the meantime I know which design my vertebrae are asking for.

-Jim

I wouldn't be shocked that they were compression fractures considering this was an offroad racing crash. However the device he was wearing was the R3 which does not attach to the lap belts. Also the crash took place off of a jump. I'm sure there was a large vertical component of the impact.

[JJLudemann]

I wouldn't be shocked that they were compression fractures considering this was an offroad racing crash. However the device he was wearing was the R3 which does not attach to the lap belts. Also the crash took place off of a jump. I'm sure there was a large vertical component of the impact.

Hmmm, you're right. The R3 doesn't have that problem. I guess I get my wish! Nevertheless, the Hybrid Pro design still looks non-optimal to me.

-Jim