Semi-OT, one of my favourite pre-plastics engineering solutions. How do you hold 5 million cubic feet of hydrogen gas in an era before synthetic polymers?

Oxgut. Hand-glued.

"Engineer Guy" Bill Hammack's knowledge is captivating and his enthusiasm infectious:

https://www.youtube.com/watch?v=ixxXhZVFXxQ

https://www.popularmechanics.com/flight/airlines/a16637939/b...