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Cargo airships could be big

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Re: Cargo airships could be big

#271

Post by wolverine876 »

ben_w wrote: post #85
kspacewalk2 wrote: post #80

Earlier quoted context omitted.

Okay, asteroids presumably make economic sense due to mining potential, but otherwise - why the hate for Venus? What's so special about being on the surface of a planet? Just don't go to where the lead vapour is, enjoy the cloudy view from 50km above the surface instead.

Might be a monkey brain, but the mere possibility of falling 50km through crushing boiling acid is the kind of thing that'll stop me getting to sleep. More so than a deadly vacuum on the other side of a wall.

If your habitat somehow fails on Mars, you have just as much chance of living. Mars' surface is much less hospitable than Venus at 50 km.

Re: Cargo airships could be big

#272

Post by cogman10 »

lordnacho wrote: post #237
dbrueck wrote: post #222

Probably a very stupid question, but can someone help me understand the following: once you have airships that have a rigid shell, why isn't using a vacuum better than a lifting gas? Isn't the buoyant force simply the result of displacing some volume of air with something less dense? (i.e. any excess lifting force comes from the fact that the mass of the hydrogen or whatever is less than the mass of the displaced air…

I think the key is in the wikipedia article: You only gain 14% lift with a vacuum vs helium. The tradeoff is either: - Build a pressure vessel to withstand the differential to the atmosphere - Let the helium do the pushing from the inside but make the thing 14% bigger I don't see how the vacuum ever wins.

> I don't see how the vacuum ever wins.

3 ways.

- Vacuums aren't combustible.

- Vacuums can be created without sourcing a gas.

- Vacuums allow you adjust buoyancy without requiring you to carry extra gases.

The major downside of a vacuum is finding something ridged enough, light enough, and cheap enough to maintain a vacuum.

Re: Cargo airships could be big

#273

Post by hutzlibu »

sitkack wrote: post #125

The article completely omits trains. That is glaring. I had this steampunk like plan when I was in college to have huge hydrogen cargo airships pulled by trains to haul large bulk items (fully assembled houses, building parts, large trees, fully assembled combines, etc). A literal skytrain. Some new lines would have to be created a way to handle going through tunnels etc. I think now I would have a drone be able to c…

This is a neat idea, but I think the main problem is, that those trains would have to go slower than an ordinary train (and much slower, than an high speed train), thus blocking the rails for normal trains.

But it might make sense for some routes.

Re: Cargo airships could be big

#274

Post by oofta-boofta »

onlyrealcuzzo wrote: post #163
vintermann wrote: post #68

Earlier quoted context omitted.

Of course it's niche applications, but it is the Zeppelin NTs which is the biggest success story. They're used for tourism in Germany and advertising in the US (the Goodyear Blimps, which as the article points out are no longer blimps at all, but much larger Zeppelins). Zeppelin Luftschiffstechnik have survived by being _very_ careful about the scale of their ambitions (i.e, it's very modest). They did deliver the th…

The Sergey Brin airship project is Lighter Than Air (LTA), in case any one was wondering. https://www.ft.com/content/ae625a25-d2ac-4bca-9508-a5f0d3c7d...

How much do you want to bet the employees working on this were apart of the anointed 12k that just got laid off

Re: Cargo airships could be big

#275

Post by hutzlibu »

TillE wrote: post #105
vintermann wrote: post #83

Earlier quoted context omitted.

Personally I'm pretty disappointed that hobby drones use so much power, when the seagulls just glide out there, not even flapping their wings for minutes on end. We should be able to manage the same with microcontrollers now, surely?

Birds are extremely light. Hollow bones, etc.

I think we can build light drones as well, but we really cannot replicate wing flapping in a way birds do. So you would need both, making it heavy again.

Re: Cargo airships could be big

#276

Post by dredmorbius »

slibhb wrote: post #228
dbrueck wrote: post #222

Probably a very stupid question, but can someone help me understand the following: once you have airships that have a rigid shell, why isn't using a vacuum better than a lifting gas? Isn't the buoyant force simply the result of displacing some volume of air with something less dense? (i.e. any excess lifting force comes from the fact that the mass of the hydrogen or whatever is less than the mass of the displaced air…

That's a fascinating idea. I googled it and came upon https://en.wikipedia.org/wiki/Vacuum_airship and https://scholarsbank.uoregon.edu/xmlui/handle/1794/22370#:~:... . Sounds like it's feasible but a materials/engineering challenge.

s/challenge/impossibility/

Re: Cargo airships could be big

#277

Post by nostromo »

splitrocket wrote: post #12

This, my friends, is why we should colonize the upper atmosphere of Venus, where you could chill outside with only a respirator, rather than the inhospitable, irradiated, mangnetosphere free mars. https://en.wikipedia.org/wiki/High_Altitude_Venus_Operationa... https://spectrum.ieee.org/nasa-study-proposes-airships-cloud...

I like the plan to have robots build a very tall mountain platform on Venus that would allow us to walk around outside on another planet, in a t-shirt and jeans (and a respirator, as you mentioned).

You could probably even grow plants on this mountain top.

After the base is established, we could start trying to terraform the atmosphere to make more of Venus inhabitable.

It's crazy to think that high-altitude Venus is more hospitable to us in many ways than is Antartica.

Re: Cargo airships could be big

#278

Post by wongarsu »

stopping wrote: post #158
padobson wrote: post #93

Earlier quoted context omitted.

Massive airships flying 90/km an hours are LESS susceptible to blockades than cargo ships? I think I'll need a little more explanation than that. Seems like a shoulder-mounted rocket launcher would be more than enough to bring one down.

Or a single tracer bullet, if it's filled with hydrogen.

Airships were routinely used and shot at in WWI, but very few were lost due to being hit.

If you think about it, it makes sense: they are massive, so the loss of pressure from a bullet hole isn't a real concern. And while the right hydrogen-oxygen mix is explosive, hydrogen needs oxygen to even burn. But there isn't any oxygen in the tank bladder. The escaping hydrogen can burn as it mixes with air if it finds an ignition source, but as long as your hull is from fire resistant material the flame can't do much, and is probably extinguished by the next wind gust.

Of course the "make your hull from fire resistant material" is where the Hindenburg went wrong. Her hull material could have been used at rocket fuel, the engineers just didn't realize that.

Re: Cargo airships could be big

#279

Post by madaxe_again »

jp57 wrote: post #55

The airship renaissance is the fusion of transportation world. It's always ten years away. Seriously, I've been hearing about the great promise of modern airships for twenty years. Where are they? Are there any airships operating commercially now outside of niche applications?

The project I am pitching currently, which has a good chunk of financing secured, envisages passenger operations in seven years.

The piece is almost spooky in its similarity to the piece I circulated to investors a month ago.

We aren’t, however, going after the cargo market.

Will it get off the ground? Who knows. But if you see kilometre-scale airships emerging from the backwaters of Europe where subsidies abound and land is cheap and regulations are… interpretable, you read about it here first.

Re: Cargo airships could be big

#280

Post by schiffern »

Retric wrote: post #256
schiffern wrote: post #235

Earlier quoted context omitted.

That's not really relevant. Charged particles from the Sun (SEPs) aren't what determine the design envelope for radiation shielding. Your overall dose will almost entirely come from galactic cosmic radiation (GCR) at much higher energy levels, which is significantly harder to shield against. Those particles are what ultimately determine your shielding thickness requirements. That's true whether you're on Venus, or Ma…

https://ntrs.nasa.gov/api/citations/20205008318/downloads/20... NASA’s direct comparisons between New Mexico (55) and Antarctica (160) only showing a relatively modest decrease from earths magnetic field when measured by high altitude balloons, but again very little GCR reaches the surface. To be clear a very small fraction of GCR is extreme high energy particles which penetrate just fine.

Hard to say, since that's in grays instead of sieverts. The two can give very different curves.

>again very little GCR reaches the surface

On Venus there would be less shielding than on the surface of the Earth.

The minimum acceptable altitude is ultimately limited by temperature, not pressure or radiation.

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