Roll Cage question .......

Well, I had a nice chat with Mick at Southern GT two years ago and he showed us the remains of a red GT40 (GTD) that crashed hard at Spa Francorchamps, september 2017 (by coincidense, we saw that crash).
He was at the point to start the rebuild of that GT.

Nothing major drama with that chassis.

He confinced us not to put a cage in our KVA B and he pointed out on that chassis why and how.
 

Neil

Supporter
To address "hitting your head" on a roll cage structure, I'd recommend this padding:


It has a softer outer padding over standard SFI 45.1 which is fairly hard but absorbs energy.
 
Well, I had a nice chat with Mick at Southern GT two years ago and he showed us the remains of a red GT40 (GTD) that crashed hard at Spa Francorchamps, september 2017 (by coincidense, we saw that crash).
He was at the point to start the rebuild of that GT.

Nothing major drama with that chassis.

He confinced us not to put a cage in our KVA B and he pointed out on that chassis why and how.
I purchased my Southern GT basically unstarted from its 3rd owner and it had a SGT roll cage installed. So, I had the same conversation with Mick following concerns after later reading Frank's article in the club magazine. Ideally, I would have liked not to have had a roll cage but for what I am going to be using the car for, I felt reassured by what Mick told me.

I know an SGT 40 with roll cage fitted was involved in a track accident, backwards into the barriers I believe, no doubt the occupants had crash helmets. I am seriously considering buying a pair of open face helmets for road use to give complete peace of mind.

Nick
 
785 views ! I am so pleased that you guys are reading this post and hopefully reacting to my concerns for safety in these cars. Frank
 
Don't have a GT40, but do have a T70 spider with head in close proximity to the main roll hoop. Thinking about ways to prevent a point impact with the bar from rear/quarter impact, one thought is run 1/8" aluminum sheet from center of headrest support out to the roll bar, then cover all of it with confor foam and upholstery. Seats have not been padded yet, so that will create more distance from seatback to headrest. In effect, the sheet acts as a bridge so my skull can't get the point load. Duplicate the same effect in the horizontal plane. Thoughts?
 

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Randy V

Admin
Lifetime Supporter
Don't have a GT40, but do have a T70 spider with head in close proximity to the main roll hoop. Thinking about ways to prevent a point impact with the bar from rear/quarter impact, one thought is run 1/8" aluminum sheet from center of headrest support out to the roll bar, then cover all of it with confor foam and upholstery. Seats have not been padded yet, so that will create more distance from seatback to headrest. In effect, the sheet acts as a bridge so my skull can't get the point load. Duplicate the same effect in the horizontal plane. Thoughts?
Tom, you’ve done a pretty nice bit of work there, but have you thought about a side impact? I’m no safety expert off the track, but I think there may be some room for improvement on your design!
 
yeah, the last line of my post references that - def need to have some kind of horizontal restraint there. All standalone race seats seem to have rigid fencing around the head/neck area. I could do the same by welding a tab projecting forward from the vertical portion of roll bar, and then padding it. but without a helmet that feature could be deadly. Wondering about just repeating the effort of bridging with another sheet of aluminum to serve as a deflector. Geometry is a little difficult, but worth the effort I think. Given all that, I think I am intent on finding a helmet I can wear while street driving - maybe a motorcycle "polo" helmet. Not great protection against a roll bar strike, but better than a bare head.
 

Randy V

Admin
Lifetime Supporter
yeah, the last line of my post references that - def need to have some kind of horizontal restraint there. All standalone race seats seem to have rigid fencing around the head/neck area. I could do the same by welding a tab projecting forward from the vertical portion of roll bar, and then padding it. but without a helmet that feature could be deadly. Wondering about just repeating the effort of bridging with another sheet of aluminum to serve as a deflector. Geometry is a little difficult, but worth the effort I think. Given all that, I think I am intent on finding a helmet I can wear while street driving - maybe a motorcycle "polo" helmet. Not great protection against a roll bar strike, but better than a bare head.
Sorry Tom - My Speed-reading got the best of me... You're on the case and I think your planning is solid..
 
Many years ago part way through my build a similar discussion came up. So I sat in the car and had a wiggle about to see what could happen.

I'm a smidge under average height at 5'8" and it was immediately obvious that I could hit my head on the roll cage even when fully strapped in on the centre bars (ie the front to back ones on the roof) and that it wouldn't take much slack (or "stretch" in an accident) in the shoulder belts to be able to smack my forehead on the front bar when thrown forward. Even the backend stepping out and then catching it could be enough for a painful smack and a side on impact didn't bear thinking about.

I made the decision then to take the roll cage out, it was either that or make the decision to _always_ wear a helmet and while I'm used to that on a bike you look a bit of a c**k putting on a helmet in a car on the road just to nip to the shops!

I did however make a change to the rear roll-over tube to allow a roll cage to be bolted to it and in _without_ dismantling half the car so I had the option should I desire it for trackdays etc. It would not obviously be _as_ strong as a one piece cage but I'd not be racing and under such circumstances would be better than no cage and as I would be wearing a proper helmet it would not have anywhere near the same risk.

As with all things there are risks and risks. These cars are massively more dangerous than your common or garden "daily" however just because they're inherently more dangerous doesn't mean you should go out of your way to make them more so.
 
You can have a half cage with no problem, its the full cage that will kill you.
Normaly a full cage has outer upper bars to support the front hoop.
On a GT40 you can not have outer bars so the only way is to use centre bars to support the front hoop.
Thing is, centre bars only support the front hoop in the middle..
In a roll over accident, the unsupported outside of the front hoop will collapse inwards & guess who is sitting there.... no helmed will save you.
 
In our cars (which are not raced, in most instances), I think we should be looking at risk mitigation. If we cart wheel the car at 100 mph+, lets face it, we are probably done. The full cage might save you, since you were wearing a helmet etc. But for the other 85% use case, just driving around, and maybe breaking the back end loose and backing into a barrier, or getting hit by an inattentive driver, the cage could kill you, or cause major brain injury. Mitigating those risks seems like low hanging fruit, so it's worthwhile. Contributing to our knowledge of how to do that is a big value add.
 
I don't think it's just the roll over that will kill you.
A 3/4 impact behind the front wheel can push the cage leg towards the driver and drag the cage down onto driver or passengers head.

Are there any positive reasons why a front cage can be a good idea?
It might be a much shorter topic!
 
Are there any positive reasons why a front cage can be a good idea?
It might be a much shorter topic!
The main one is that there is very little strength in the A pillar and the car itself being very low any impact into a high vehicle (or unfortunately with the rise of Crossovers, SUV's etc "average" cars) could see an impact to the front of the car causing the other car to ride up, over and then crushing the passenger compartment. A front cage would add significant strength and (hopefully) prevent that.
 
Re the front cage, if you were upside down and sliding in the forward direction, provided the initial impact didn't fold the cage, it would be of benefit. Obviously a very narrow case.
further to this discussion, does anyone have experience with Confor foam? I understand the pink/soft foam is the stuff used in F1 cockpit surrounds. Wondering if this is the right stuff to use in a headrest/head restraint system. I have a bunch of the blue foam coming to pad out the seat and am tempted to try it out in this application.
 

Randy V

Admin
Lifetime Supporter
I wasn’t going to post these photos, but they are elsewhere on this forum.
This was the GT40 belonging to a much valued and appreciated member here - Tom Schwab.
While we don’t have all the details about this crash, we can tell you this much. Tom’s passenger died at the scene. Tom suffered massive head and upper body injuries and was in a coma for many months. Ultimately Tom passed away, never having regained much if any consciousness.. Devastating blow to our community and obviously his family.
While we cannot say without a doubt that the roll cage in Tom’s car was a contributing factor to the injuries and death - I think it’s safe to say that the cage did not prevent their fates...
If Tom were here today, I think he’d advise a good degree of padding to your cages, if not eliminating them altogether...
Cages can be made to bolt in/out so they could be in place during track days or other competition where helmets are used.
 

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