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The lifting power of helium is small, as opposed to hydrogen. Also, helium has supply problems. Is it not possible to have a modern airship with hydrogen as i
by DrScump 9y ago
The lifting power of helium is small, as opposed to hydrogen. Also, helium has supply problems.
Is it not possible to have a modern airship with hydrogen as its primary lifting agent?
- mikeash 9y agoHydrogen doesn't buy you that much additional lifting power. Air is about 1.2kg/m^3 at STP, so that's the theoretical maximum you can lift with a cubic meter of gas bag. (And you can only get that value if you could somehow hold a vacuum, of course.) Hydrogen is about 0.09kg/m^3 at STP, so you can lift about 1.1kg/m^3. Helium is about 0.18kg/m^3, so you can lift about 1kg/m^3. Helium is twice as dense, but that only costs you about 10% of your lifting power since both are so light compared to air. I see no reason you couldn't use hydrogen, but I don't know if anyone would want to take the risk. (Specific flaws of the Hindenburg aside, hydrogen is explosive across a distressingly wide range of mixture ratios with air.) If you did use hydrogen, I think the main motivation would be avoiding the use of scarce helium, not the minor increase in lift capacity.
- ForHackernews 9y agoIf it's an unmanned drone-blimp, the safety issue because somewhat less critical.
- gozur88 9y agoBut still critical enough to make it impractical. How would you do maintenance on a hydrogen airship without risking the people doing the maintenance? And you'd never be able to fly over populated areas.
- petre 9y agoIt is possible but we all know what happened to the Hindenburg. Using hydrogen is asking for a fire to happen. https://en.m.wikipedia.org/wiki/Hindenburg_disaster https://en.m.wikipedia.org/wiki/Hindenburg_disaster
- DrScump 9y agoFar more helium airships have wrecked than hydrogen airships, even counting only before the Hindenburg.
- petre 9y agoWrecked, yes, but they probably didn't burn like a torch with people jumping out of them to avoid burning alive.
- Nomentatus 9y agoWhat you saw was the engine-fuel burning on the ground; the hydrogen went straight up in flames and burnt no-one.
- lostlogin 9y agoKeep in mind that the Hindenburg was supposed to be helium filled, but due to import restrictions they couldn't get enough.
- honestoHeminway 9y agoVacuum still has the best lifting power of them all..
- guelo 9y agoWe just need a material as light as a balloon but rigid enough to hold its shape and maintain a huge vacuum at 1 atmosphere outside pressure.
- scarmig 9y agoPerhaps graphene aerogel, with a nonpermeable graphene casing? I'm not sure of what its behavior would be with all its air sucked out, though.
- honestoHeminway 9y agolike a hair full of nothing..