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A couple other options beside hydrogen/helium: vacuum chambers, hot air. I don't know if we have the technology to build a compressive structure that can withs

by elihu 5y ago

A couple other options beside hydrogen/helium: vacuum chambers, hot air. I don't know if we have the technology to build a compressive structure that can withstand atmospheric pressure and yet be lighter than the air it displaces. That sounds like an interesting problem to work on. I imagine getting it to work out would be easier the larger the structure is, within reason. I assume that hot air isn't competitive with either hydrogen or helium in terms of lift, and it takes additional energy to keep it hot. On the other hand, air is free and it's not inherently flammable by itself. Maybe a well-insulated airship that acts as a solar greenhouse could get quite warm and stay that way?

ant6n 5y ago
> I don't know if we have the technology to build a compressive structure that can withstand atmospheric pressure and yet be lighter than the air it displaces. That sounds like an interesting problem to work on. I imagine getting it to work out would be easier the larger the structure is, within reason. It doesn´t exist so far. There are very strong forces involved. I`d say it´s more likely there would be connected small enclosures that could make that work. Perhaps some sort of solid foam blocks with vacuum inside - but it may provide much less lift than a true vacuum.
elihu 5y ago
To follow up my own comment: I suppose these aren't mutually exclusive. For instance, you could have an airship filled with hydrogen or helium at 1/2 atmospheric pressure and kept hot by solar heating. For helium especially it might be an effective way to keep costs down (since helium is so expensive) and maybe keep it from leaking out quite so much. Similarly, using hydrogen at partial vacuum would mean having less of it on board, which is sort of good from a flammability point of view. Though on the other hand, it means that if the skin is ever broken you'd have outside air mixing very quickly with the hydrogen inside due to the pressure difference. That's probably a bad thing.

by elihu 5y ago

ant6n 5y ago

> I don't know if we have the technology to build a compressive structure that can withstand atmospheric pressure and yet be lighter than the air it displaces. That sounds like an interesting problem to work on. I imagine getting it to work out would be easier the larger the structure is, within reason. It doesn´t exist so far. There are very strong forces involved. I`d say it´s more likely there would be connected small enclosures that could make that work. Perhaps some sort of solid foam blocks with vacuum inside - but it may provide much less lift than a true vacuum.

elihu 5y ago

To follow up my own comment: I suppose these aren't mutually exclusive. For instance, you could have an airship filled with hydrogen or helium at 1/2 atmospheric pressure and kept hot by solar heating. For helium especially it might be an effective way to keep costs down (since helium is so expensive) and maybe keep it from leaking out quite so much. Similarly, using hydrogen at partial vacuum would mean having less of it on board, which is sort of good from a flammability point of view. Though on the other hand, it means that if the skin is ever broken you'd have outside air mixing very quickly with the hydrogen inside due to the pressure difference. That's probably a bad thing.