At 99°C (210°F) the lift power of hot air balloon is 0.25 kg per m³. Pillars supporting a four kilometre long suspension bridge section are under 200 MN vertical load, or 20 million kg. The air balloon would have to be 80 million m³ large, or 534 m (⅓mi) in diameter.

[–] Burninator05@lemmy.world 7 points 1 month ago

So you're saying its possible.

[–] Obi@sopuli.xyz 3 points 1 month ago

Doesn't even sound that unrealistic to be honest.

[–] RememberTheApollo_@lemmy.world 1 points 1 month ago (1 children)

Does that mass include the containment and support structure for the balloon itself?

[–] nitroemdash@lemmy.wtf 1 points 1 month ago

Surface area is 895844 m², Dycron weights 4 ounces per sailsmakers yard, or 0.171 kg per m². 153458 kg, so additional 38365 m³ required, supports should also be relatively light. Quite negligible compared to, for instance, cars weight.