Hello,

Hi,

Firstly nice waggon!  My friend has a mantits (deliberate typo) which has just been supercharged.  With respect to your roll over bar I'd say it is possible in carbon BUT you'd need to test it to determine structure.  Even then it would only be known for the situation of the test.  This would be very costly.  As you say, steel is a known quantity which is why its used so heavily.  IMO you're best sticking with a steel roll over bar (yes I know its heavy) but your life may depend on it.  If you intend to race at all then it will have to be steel to pass scrutineering.

If you are trying to save weight the best option is to remove it from the body panels.  IIRC marcos jsut use GRP for panels so weight can be saved there.  There are other options if you need more weight savings.

Thanks FLD,

There is the risk that if you make a composite one and (heaven forbid) you do roll it then you could end up with shards of carbon flying round the cabin.  I'd do it in steel or don't do it TBH.  These cars have a very C of G and I've not sen one rolled so as a fast tourer I'd be impressed if you did roll it!

Don't do it !

Done lots of crash structures in F1 and thou your not going to see the forces we see if anything did happen its still going to be a fair bit of force

It "could" be done-but not easily

Two main problems for you are -

1-What ever your end design was just like every one else you have to crash test it to have proof of concept

2-Fitting, one of the main areas do design goes into intergration  of the roll hoop into the main structure to spread the loadings.

Your existing chassis set up will be far from ideal and leads to a compromised composite structure before you even start

Composite structure can be very good in the initial crash,not very good in a secondary impact

Thanks f1rob,

Carbon fiber is very brittle, it means impact absorbing very low energy, at the same time glass fiber is brittle but 4-5 times better than carbon fiber in terms of absorbed energy. I think u should use ductile metals, safety first

My vote would be for a steel cage as well but just for information. This thread reminded me of this OakleyDesign carbon roll cage.

http://www.oakleydesign.eu/oakley-design-carbon-fibre-roll-cage

https://cornerbalance.wordpress.com/2009/02/07/design-innovations-carbon-fiber-rollcage/

Craig

Some time ago safety devices offered aluminium roll cages for mk2 escorts.  I believe the company has changed hands since then but it's worth a phone call to see if you could get one made for your car.