I spotted something I didn't see anyone else mention. Your upper truss mount locations are in the mid-span of each quarter of ring, between struts mounting the top ring. This means the bottom ring is not taking advantage of the rigidity provided by the upper ring. I recommend a thin sheet of carbon fiber or similar to tie the two rings together (with lots of screws all the way around). This will reduce any flexure of the lower ring at the truss mount points.
Impressive build!
Scott makes a good point. Adding a web between your UTA rings will add a ton of stiffness to the structure.
I have never worked with carbon fiber but go the cheap route with aluminum roof flashing from most any hardware store. Can be found in various widths 6", 8", 10" etc. I used 8" flashing for my recent build and the cost for a 10' roll was about $15 IIRC. It can be easily cut with a razor by scoring and folding at the score line. I sand the snapped edge and then hem it between a couple wood blocks to hide sharp edges and corners even more and creates a stiff section to attach to the focuser board. Then I match drill the inside about every 2-3" and secure with #6 black zinc screws. Lot of builders use Kydex for the web but it has a tendency to warp in the hot desert sun. I also recently added Protostar flockboard to about half of my UTA opposite the focuser. In hindsight the flockboard might be sturdy enough to be used by itself as a web material.
Edited by Psalm19One, 28 August 2024 - 10:03 AM.
