• nitroemdash@lemmy.wtf
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    1 day ago

    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.

      • nitroemdash@lemmy.wtf
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        3 hours 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.