when are you going to be in a situation that you can start fabrication of the cages?

Are they for decoration or to perform a functon? Roll over protection perhaps?

A badly designed roll cage is worse than no roll cage. Without the diagonal the roll hoop could collapse in a roll. Without rear supports it can collapse going end over end.

Even properly designed cages deform in an accident. Have a google there is plenty of food for thought.

Hi, how much extra will there be at the un cut ends would say?

Thanks
Daveyb

Hope this is is taken as a consructive comment,I personally would like to see the front legs go to the floor and side bars fitted to the legs and bracketed from lower chassis rail.

Constructive and not derogatory. At least you bother and put the time in.

I'm not being negative. Only pointing out that something designed to afford protection to the driver and passenger should do just that. I admire Phil's dedication to producing parts for the Haynes Roadster.

A roll bar should be high enough to be above a helmeted head. Draw a line from the top of the front of the chassis to the top of the roll bar. If your head is a reasonable distance below this then that is fine.

The roll bar needs to be braced diagonally to prevent it from folding sideways.
The roll bar needs to be braced rearwards to prevent it folding front to back (These braces don't have to be straight. They can be bent to pick up the chassis at suitable point).

If you do that then the MSA approve it.

Any more parts aren't strictly necessary. If there are more parts fitted they need to be done in in the same way.

I am not suggesting this is easy to do, especially with a completed car. As an example MK's roll cage doesn't meet MSA regs due to the double bend in the front leg.

As Phil described in his initial discussion, its an external cage. Therefore can't go down to the floor as it would end up going through exhausts etc. I like the design and as Phil has pointed out, its meant to be an improvement over the roll over hoop. Having driven my completed Haynes for a year now, I can fully appreciate how exposed your face is to road debris and thats why I'm after the cage.... not for rolling the car, but from collision protection.

To me the front of the frame looks very similar to a Caterham R400 cage

Have you looked the FIA requirements for roll cages? It would be nice to have a compliant design.

Any chance you could manage to shape the top cross like the caterham in the pic above?
I do like the 2 half moons.
Can you send me a quote for the full light weight cage in flat pack form with side bars, rear cross in the hoop and the above mentioned half moons upper.
When are you starting to fabricate these?
What's the thoughts on deliver/collection?

Taken all comments onboard from the above and should have read and digested it better.

I did not take on board it was totally external and went into "safe mode" thinking of what would fold and what would reinforce.

Comment on rdodger's post,possibly the top of the rocker box will be the first point of contact in the event of a roll and I think the blue book measures it from there and as I posted previously the Teamtrain Roadster had one built to that spec.

Anything fixed to the side chassis of greater diameter and substance must add a greater safety factor as the length of the sides are possibly the weakest point in respect of accident damage at the sides.

If you want safety,stay in the womb.:) :)