u/Inevitable-Fox-3601

A transparent ETFE sphere contains a spherical concentrator that focuses sunlight onto a ceramic receiver, heating the internal air to generate lift. No combustion, no helium, no batteries.

The rotation mechanism uses two "pearl necklaces" — wires strung with small freely-rotating spheres that grip the envelope when tensioned and roll freely when not, allowing the concentrator to track the sun.

Still in the concept and early testing phase. Full documentation and updates on GitHub and Hackaday — links in comments.

Thoughts and challenges welcome. Especially the brutal ones.

https://hackaday.io/project/205609-nimbus-concentrated-solar-thermal-flight