Roll Cage question .......

Takis M.

Supporter
Guys, is there a real cause for concern that the roll cages may actually inflict heavy injuries on the occupants if involved in a road accident (i.e. without wearing helmets)?
I know there is a requirement for the roll cages for racing and track use but then we wear helmets. But can the roll cages also cause bad injuries even in relatively low speed accidents on the roads because of how close they are to our heads?
Is there a case therefore for not fitting a roll cage if the car is intended only for road and non-race use and perhaps beef up the engine bulkhead to act as a roll bar just in case?
Thoughts please?
 

Takis M.

Supporter
Do we know what the ratio of replicas are with / without roll cage? (not including the pressed steel monocoque centre section ones).
 

Neil

Supporter
The evidence shown in that article supports the view that a badly designed or flimsy roll cage is not a good idea. A roll cage is not (or should not) be a cosmetic device, it is there to protect the driver from intrusions into the cockpit due to an accident. The roll cage that collapsed far enough to the rear to contact the carburetor was obviously far from being enough protection.

As far as head impact with the cage, some racing organizations require SFI 45.1 padding on all surfaces that may come into contact with your head (helmet).

Last September my friend Rob Freyvogel crashed his streamliner at 432 mph. His roll cage structure protected him very well but the incredible G-forces involved in that crash caused a closed brain injury that has taken time to recover. Fortunately, with immediate response from the course safety workers, an air evacuation to a Salt Lake City trauma center, and loving care by his wife, Sue, and a dedicated team of doctors and therapists, Rob is now able to walk and talk but it will still take time for a more complete recovery.

Racing is inherently a dangerous activity. Hemingway said that there are only three sports- mountain climbing, bull fighting, and motor racing. All the others are merely games.
 

Takis M.

Supporter
Agreed. For me at least it's made me take a step back from my build and consider how best to proceed. For the duration of my build I will remove the roll cage. I will beef up the engine bulkhead. I was already decided to place additional struts (one either side)art of the bulkhead to add strength. Once my engine and box and exhausts are in I can figure out how to run them and sizes. I will also speak with a local motorsport outfit about beefing up the bulkhead to have sufficient strength to act as a roll over bar (god forbid).. Either way I am inclined to do something in place of a roll cage, eventually. A friend (and fellow GT40 builder and forum member) found someone in Sweden (or Finland, I forget) producing the pressed steel centre section. It will need work to fit of course and also strengthening to be safe for the occupants but its only one possibility and I am still reviewing all options. Have loads of time and work to do before I get to IVA approval status.............anyone has more input on this subject (although the articles provided by Frank Catt are pretty conclusive) would be appreciated......
 
To be honest, I can hardly imagine a car like the GT40 without a safety cell.
That a helmet should be mandatory is actually self-evident.
But I also think of things like the fastening of the seats etc..
Unfortunately the two outer corners at the front bracket of a safety cell make it a bit difficult.
Because of the cutout in the roof you can't support them.
They can buckle in case of a rollover and thus possibly make it more difficult to get out of the car after the accident.
But then what is the alternative?
Just a roll bar and some plastic around you?
I don't know what to think about this discussion, condemning something is one thing, but then you should also suggest better solutions.
I would be very happy to have a discussion on this topic, because you always learn something new and safety concerns us all!
Frame_Type_B.jpg
 

Ian Anderson

Lifetime Supporter
Hi Frank
i was one of those statistics and remember looking and reading that in the club magazine, and finding it rather sobering.
Around that stage I was actually thinking of getting a cage fitted, instead I chose not to and as someone pointed out once .....drive It like you are on a motorbike and be aware of what is around you, your driving ability and the currentroad conditions.

Ian
 

Takis M.

Supporter
the proximity of the roll bar tubes to your head is the main danger and second is the deforming of the roll cage structure in an accident which then either pins down the occupants or hurts them (or both) ....... Is that it? have I missed something?
I am on the lookout for a solution like I said. I am not even a third into my build yet so have some time to research and discuss to find a solution. At first I wanted to reform the roll cage using the smallest diameter tubing permitted by the RAC (in the UK) and have it follow more closely the curvature of the centre spider body section thereby increasing distance between heads and roll bars and increase the wall thickness to improve strength. However the fixing of the roll age by bolts alone to the chassis makes it vulnerable to movement in a shunt and hence inherently dangerous. I feel that I will only come up with a solution once my car is complete and I can see how or what can be introduced to keep the look and improve the safety in all regards.......work in progress. Up until that point it will be driving like you're in a Cobra...
 

Neil

Supporter
I'll post a picture of my chassis that shows its roll cage structure. The roll cage is per SCTA rule book requirements: 1 3/4" OD 0.125" wall 1020 steel tubing. This is seriously strong and well braced. Note the required 1/8" gusset plates at weld joints. The idea behond a roll cage is not simply protection from a roll-over, it is from rolling, tumbling, or even hitting something that would otherwise decapitate you. As I said before a roll cage should not be a cosmetic device.
 

Attachments

Takis M.

Supporter
Neil I can see that in the lower forward parts where your cage connects to the chassis it is seriously beefed up and well planted with a cross member and gussets. That's the issue with a lot of the ones that are only bolt on in those locations, without additional cross members and strengthening. They will not hold their shape and protect the occupants even in relatively slow speed shunts. And I am guessing that's why in the previous photos put up in this thread those 'bolt on cages' suffered as a result and so did the occupants.
 
A great example of an integral safety cell.

What a pity that the 1/8" thick gussets can't be used on a GT40 cage due to the lack of a perimeter tube around the roof area.
No one seems to be saying it but ....

In my opinion, the GT40 design just doesn't lend itself to the creation of a safety cell without the inclusion of additional steel work that's cosmetically undesirable.
 

Takis M.

Supporter
Unfortunately that's the truth but also that the unsightly safety cell is inherently dangerous to the occupants because of the proximity to their heads. There must be another way of solving this, maximum safety for the occupants (without the risk of hitting their heads on the roll cage even in low speed encounters, as well as keeping the aesthetics...........
 
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