Hi Folks, thanks for making this forum.
There's loads of great advice here. 

I've been making 60 cm diam rings by bending 5mm carbon rod , setting the ends inside a cuff and sewing these inside a dacron sleeve.
This puts the carbon rod under a lot of initial stress. So much that vinylester rods break randomly in the night. I should use epoxy.
From here they are compressed even more by 6 lines on a tensile torque transmission system. 
This is a very weird project making a flying wind turbine... https://windswept-and-interesting.co.uk

I'd love any suggestions or advice on how to make these rings better. ..I can't afford a bike wheel for every ring in a stack
Is there anywhere which makes a set pultruded coil which I could cut and set as a ring?
Is there anyone makes a prepreg packing or sealing gasket I could wrap around a large cylinder?
Should I just make corner blocks and use straight rods?

Thanks in advance

Do the rings have to be carbon fibre? The fibreglass pultruded rods would be more resilient than the carbon for the same size.

Or a slightly smaller dia carbon rod or a better grade or carbon ??

Or as suggested layup your own if you can find a large piece of metal tube that would make a good mould to use, then they could be wet laid or pre preg and even a sandwich structure. Layup a piece of it and then cut this into the rings.