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Cargo Airships Are Happening

(www.elidourado.com)
220 points elidourado | 17 comments | 14 Oct 24 16:31 UTC | HN request time: 0.905s | source | bottom
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xnyan ◴[15 Oct 24 00:04 UTC] No.41843568[source]▶
The (biggest) problem that keeps airships from practical use is that they are huge sails. Big sails mean even small amounts of wind can be powerful forces acting on the airship. In the air a big push from the wind might be safely managed, but if you're near anything solid such as the ground, you can get smashed to bits.

To safely operate a suitably efficient (large) airship, we'd need both huge specialized docks with extremely strong mooring structures to keep wind from smashing the airship into whatever is near it, and a system (such as a 3-axis propulsion system on the airship) that is capable of counteracting wind force acting on the airship when it's near the ground or other solid objects and not docked.

Despite the many attractive advantages of airships, there's yet been anything like a good solution to this problem. There are other challenges too (what do you do when you drop off your cargo and the airship wants to shoot up into the air? Vent gas? Rapidly compress your gas?), this is just the biggest.

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labcomputer ◴[15 Oct 24 00:40 UTC] No.41843759[source]▶
> There are other challenges too (what do you do when you drop off your cargo and the airship wants to shoot up into the air? Vent gas? Rapidly compress your gas?)

Not to detract from your overall point, but you do the same thing you do when burning fuel while cruising: Add ballast.

Yes, but how do you add ballast to an airship while it is underway? Simple: condense water out of the exhaust like the zeppelins did.

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1. zabzonk ◴[15 Oct 24 02:38 UTC] No.41844403[source]▶
> Simple: condense water out of the exhaust like the zeppelins did.

Citation? Would not the condenser need to burn fuel, thus lightening the ship?

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2. imoverclocked ◴[15 Oct 24 02:53 UTC] No.41844471[source]▶
You are carrying fuel and using oxygen from the atmosphere to combust it. When it's hot, it's a gas. By simply cooling it and recovering most of it, you are potentially left with more mass than you started off with... and Oxygen is relatively heavy.
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3. sethherr ◴[15 Oct 24 02:56 UTC] No.41844480[source]▶
The article describes electric airships
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4. mitthrowaway2 ◴[15 Oct 24 03:07 UTC] No.41844526{3}[source]▶
The GP asked about burning fuel. But in the case of electric airships, you can run an electric condenser, extracting atmospheric water vapor.
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5. shiroiushi ◴[15 Oct 24 06:48 UTC] No.41845659{4}[source]▶
That seems like it would be really bad for energy efficiency: now you need batteries large enough for propulsion during the whole trip, plus extra for extracting water vapor.

Why not just take on some liquid water at the destination when you drop the cargo?

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6. ◴[15 Oct 24 11:42 UTC] No.41847495[source]▶
7. bondarchuk ◴[15 Oct 24 12:33 UTC] No.41847901{4}[source]▶
You're both missing the forest for the trees, when the airship is electric obviously you don't have to add ballast while flying because you don't have to compensate for burnt fuel.
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8. pclmulqdq ◴[15 Oct 24 12:46 UTC] No.41847995{4}[source]▶
This idea of extracting water from air keeps coming back, but every time someone tries it, they learn of the same thermodynamic limits. It is extremely energy-intensive to extract water from the air, and it only really works if the climate is humid enough that there is water in the air to extract. This is exactly what a dehumidifier does, and the off-the-shelf version you can buy at home depot is no more than 5-10x worse than the thermodynamic limits - those generate a pitiful amount of water for a lot of energy intake.
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9. Qwertious ◴[15 Oct 24 13:57 UTC] No.41848662{5}[source]▶
The ballast is for cargo, which needs to be picked up and dropped off. Fuel is just a potential solution.
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10. Qwertious ◴[15 Oct 24 14:05 UTC] No.41848744{5}[source]▶
Do we even need to extract the water? The point is to capture weight, and the only reason to liquefy the water is to store it more efficiently, by volume.

Storing higher humidity air doesn't sound very efficient, storing liquefied humid air sounds like a disaster waiting to happen, and storing compressed air sounds like an unnecessarily complicated alternative to just compressing the hydrogen.

11. Qwertious ◴[15 Oct 24 14:07 UTC] No.41848770{5}[source]▶
Because that's less flexible and there may not be water at the destination in the first place. That said, Flying Whales are trying to do exactly that, because ballast tech just isn't capable enough yet.
12. QuadmasterXLII ◴[15 Oct 24 14:21 UTC] No.41848914{3}[source]▶
The article describes diesel electric airships.
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13. Ajedi32 ◴[15 Oct 24 15:23 UTC] No.41849559{6}[source]▶
Why condense water from fuel or the air then when you can just connect to the local municipal water system? You're already at port!
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14. dotancohen ◴[15 Oct 24 16:58 UTC] No.41850586{4}[source]▶
The fine article shows them lowering a container from a crane. I'd love to see them connect the crane to an electric generator and actually regen the potential energy of the container into electricity.
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15. imoverclocked ◴[15 Oct 24 23:33 UTC] No.41854191{5}[source]▶
Even more efficient might be raising another container at the same time in a (mostly) balanced manner. Then you don't have as much loss from conversion/storage.

Fun fact: many inclined elevators work this way :)

16. Qwertious ◴[15 Oct 24 23:33 UTC] No.41854194{7}[source]▶
Not necessarily - the great thing about airships is that they can go anywhere, and pick up cargo at places that aren't ports. You can go pick up logs from logging camps directly, for example.
17. c_o_n_v_e_x ◴[20 Oct 24 08:50 UTC] No.41893986{5}[source]▶
Or you try to capture water that's already condensed... cloud droplets.