11 ms·

Vacuum has only around 10% (iirc) more buoyancy than hydrogen in the atmosphere, so the gains would be very minimal while the added constraints due to having su

Vacuum has only around 10% (iirc) more buoyancy than hydrogen in the atmosphere, so the gains would be very minimal while the added constraints due to having such a large pressure difference would be huge. Vacuum airships are an interesting concept but have not advantage compared to gas airships in practice.

yoz-y 7y ago
I see at least two advantages: compared to hydrogen they are not flammable and compared to helium they don't require a limited resource.
- WalterBright 7y ago
  You'd need a very heavy chamber to keep the vacuum balloon from collapsing. Hook up a vacuum pump to a flask. It isn't going to rise as the air is pumped out. Edison's light bulbs did not float.
  - yoz-y 7y ago
    > You'd need a very heavy chamber to keep the vacuum balloon from collapsing. That was my original question: is it technically feasible to make such a chamber from light enough materials (my first guess would be some carbon tubes supporting a carbon fiber tarp or something like that. > Edison's light bulbs did not float. One could argue that it was too small (of course I imagine making a massive lightbulb would not make for a good solid structure, also glass is heavy). A hot air balloon does not float either if you lest it too much.
    - reeeeee 7y ago
      This topic has been discussed for ages, but no feasible solution has been found as of yet.[1] https://en.wikipedia.org/wiki/Vacuum_airship https://en.wikipedia.org/wiki/Vacuum_airship
    - alexisread 7y ago
      It is worth noting that at a helium balloon's upper altitute, vacuum balloons would be more feasable as the air pressure allows thinner materials. Some sort of hybrid for say weather monitoring might be feasable.
- dredmorbius 7y ago
  Partial vacuum on a steel railroad tank car, for comparison. https://www.invidio.us/watch?v=Zz95_VvTxZM https://www.invidio.us/watch?v=Zz95_VvTxZM

yoz-y 7y ago

I see at least two advantages: compared to hydrogen they are not flammable and compared to helium they don't require a limited resource.

WalterBright 7y ago
You'd need a very heavy chamber to keep the vacuum balloon from collapsing. Hook up a vacuum pump to a flask. It isn't going to rise as the air is pumped out. Edison's light bulbs did not float.
- yoz-y 7y ago
  > You'd need a very heavy chamber to keep the vacuum balloon from collapsing. That was my original question: is it technically feasible to make such a chamber from light enough materials (my first guess would be some carbon tubes supporting a carbon fiber tarp or something like that. > Edison's light bulbs did not float. One could argue that it was too small (of course I imagine making a massive lightbulb would not make for a good solid structure, also glass is heavy). A hot air balloon does not float either if you lest it too much.
  - reeeeee 7y ago
    This topic has been discussed for ages, but no feasible solution has been found as of yet.[1] https://en.wikipedia.org/wiki/Vacuum_airship https://en.wikipedia.org/wiki/Vacuum_airship
  - alexisread 7y ago
    It is worth noting that at a helium balloon's upper altitute, vacuum balloons would be more feasable as the air pressure allows thinner materials. Some sort of hybrid for say weather monitoring might be feasable.
dredmorbius 7y ago
Partial vacuum on a steel railroad tank car, for comparison. https://www.invidio.us/watch?v=Zz95_VvTxZM https://www.invidio.us/watch?v=Zz95_VvTxZM