Lotus Elan Central

I have been looking for a functional roll bar for a while, but unable to find one that is in my price range (£600 max). So have been thinking how to fabricate one that will provide a good degree of protection. The outboard fixings are my main concern. Initial thoughts are to fix the bar to plates under the 2 rear fixing bolts of each seat, at least the inner bolts would attach to the chassis and the seats themselves would be tightly coupled with the bar. A V brace into the hood storage area, bolted into the chassis spine would hopefully provide good support. So something like the pics attached.





I was considering if some fixing into the sill, using the seatbelt anchor bolts, would be sensible, but that does complicate things and may not be of much benefit or may be positively wrong.
Once I have more confidence in the scheme, over the winter I plan to firm up on the dimensions and angles, investigate where the chassis is under the hood storage area, determine how much fibreglass needs to be cut out to make that chassis connection, then make a mock-up from plastic waste pipe to see if the folding hood can clear it.
Anyone have comments on the scheme ? Is this a waste of time? Could it be a safety hazard? How could it be improved?

Ken,
Roll bars have been made in the past by lotusgirlmarie and by Kuching. I presume that you're aware of these. Unfortunately, most of the information on the design and development of these has been lost through the mysterious phenomenon of disappearing threads. However, there are a few posts left which should give you some ideas. In case you haven't found them, have a look at these:

viewtopic.php?f=85&t=21894&hilit=Roll&start=116
viewtopic.php?f=85&t=14880
viewtopic.php?f=79&t=2737&start=482

John

Thanks for the links, interesting pictures showing the detail of the 13 fixing points, it does suggest I need more substantial fixings! I have cut some 40mm plastic pipe to see what clearances are at the sides as the hood folds. Once I have a basic profile I'll think more about those fixings.

I have the LGM rollbar - it is great and the top just squeezes up against it enough to open and close the tonneau cover past it. It has a major central mounting next to the battery and it has substantial mounts that go down by the seatbelt anchors. I seem to remember that they did some calculations and it was strong enough to cater for all but a flip directly over the longitudinal axis of the car. It certainly makes me feel more comfortable driving it and provides an excellent place for a windblocker!

I'll see if I can find the old fitting instructions that LGM made. They were excellent.

Candles.