6 ms·
The advantage over hydrogen at atmospheric pressure is really minor, too.
by idlewords 12y ago
The advantage over hydrogen at atmospheric pressure is really minor, too.
- dredmorbius 12y agoOther than vacuum not burning.
- idlewords 12y agoYeah, your balloon just implodes at the speed of sound. In terms of disastrous outcomes, it's pretty much the same thing. Hydrogen explosions are scary, but the ball of flame also rises very quickly. Most of the people on the Hindenburg survived.
- panzi 12y agoI wonder what would have happened if a Vacuum airship would have had a similar accident. Meaning a hull breach at a 200m (650ft) altitude. No fire, just a bit of a drop. Maybe shrapnel? Well, I guess it would drop much faster.
- dredmorbius 12y agoGiven that there are no vacuum containment systems large enough to support the Hindenberg, it would never have taken off in the first place. Given that what precipitated the failure of the Hindenberg appears to have been either an initial slow leak which caught fire, or a fire which consumed the gas envelopes, possible as little as a gradual loss of lift. Even in the case of sudden failure, it would depend on how many lift compartments existed -- you'd lose 1/n of your total lift, so presumably a pronounced but possibly controlled descent.
- porpoisemonkey 12y agoThat's true for buoyancy but vacuum definitely has a major advantage in area of flammability.
- k__ 12y agoWhat happens if a vacuum sphere that can lift 10t implodes?
- dredmorbius 12y agoYou lose 10t of lift. If a hydrogen envelope of 10t ruptures, you lose 10t of lift and have a major fire hazard.
- idlewords 12y agoYou lose 10t of lift in a horrifyingly destructive implosion: https://www.youtube.com/watch?v=Zz95_VvTxZM https://www.youtube.com/watch?v=Zz95_VvTxZM
- dredmorbius 12y agoAnd here's what hydrogen does. Note the comparison is of a pure H₂ vs. 2 χ H₂ + O₂ mix. https://www.youtube.com/watch?v=qOTgeeTB_kA https://www.youtube.com/watch?v=qOTgeeTB_kA
- ars 12y agoHydrogen is not as major of a hazard as it looks. It's lighter than air, and will rapidly leave if it escapes. The real trick is making sure no oxygen gets in. In contrast a leak is not super dangerous. It will still burn of course, but if the skin is flameproof it won't do much harm to the ship as a whole. So what you do is make sure it's enclosed in cells of a flameresistant material. That way a fire won't spread and will rapidly rise away and put itself out.
- dredmorbius 12y agoThe range of explosive concentrations of hydrogen gas means that either oxygen in low concentration or hydrogen in low concentration are highly explosive. If you've a leak, pretty much by definition, oxygen is getting in.