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Cargo airships could be big

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Re: Cargo airships could be big

#61

Post by black6 »

greesil wrote: post #57
btilly wrote: post #50

It is fun to read the analysis. But they are right that we don't have the ability to make enough helium to make that make sense. I can believe that hydrogen can be made to work. But when they got to making the frame out of magnesium - a leak in the rain would be scary! This is one of those ideas that seems better in theory than practice. Not as bad as the fact that adding mercury to rocket fuel makes it go better. Bu…

I don't understand this. LH2/LOX typically burns on the rich side to increase exhaust velocity. This means more momentum for less mass, which is what you want from a rocket. This is the opposite.

John Clark goes into detail in his book Ignition! about why smaller, lighter exhaust molecules are much better than larger and heavier ones.

Re: Cargo airships could be big

#62

Post by jcranmer »

djtango wrote: post #34
traceroute66 wrote: post #11

Earlier quoted context omitted.

> There's no doubt they'll be big, but will they be practical, economically viable and successful? Frankly no. Its like every few years people remember about airships and suddenly start shouting how its the answer to the world's problems. I mean, just search here on HN... 11 years ago there was "Blimpocracy - Is the airship the transportation system of the future?"[1] .... now here we are 11 years later, and, well, y…

What about places with limited rail/roads like Alaska and Kazakhstan?

In general, where there's limited infrastructure, there's limited demand for infrastructure.

I can't speak for Kazakhstan, but most of rural Alaska is adequately serviced using tiny Cessna-sized aircraft for shipping, and the parts that aren't (say, Prudhoe Bay) already have existing ground and/or marine infrastructure to supply them.

Re: Cargo airships could be big

#63

Post by jliptzin »

Is there any discussion about personal airships? I wouldn’t mind the slow speed if it meant I could go to sleep in a quiet, bump free, spacious craft and wake up a couple hundreds miles away at my destination (weather permitting, of course).

Re: Cargo airships could be big

#64

Post by lkjdsklf »

actionfromafar wrote: post #16
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...

A respirator and a teflon suit to keep the sulfuric acid clouds away from your skin?

sure teflon might not be the most comfortable, but think of the speed we could get on a slip n' slide

Re: Cargo airships could be big

#65

Post by mark212 »

The leisure market is huge for airships, in my opinion. Think of the same people that go on cruises to Antartica, but flying gently and at much lower altitude than a plane, over wild and scenic parts of the world. With luxury accommodations.

Re: Cargo airships could be big

#66

Post by jodrellblank »

I'd like to draw your attention to "killing 35 of the 97 people on board in the inferno."

The Hindenburg had 7 million cubic feet of Hydrogen gas. It was the biggest aircraft disaster of its time. It had such rudimentary technology that the cockpit looked more like a sailing ship than an aircraft[1]. Despite that, well over half the passengers jumped out the windows[2], ran away and survived with few or no injuries.

When was the last time a jumbo jet crash landed with complete loss of the aircraft and all the combustible stuff burning it into a molten metal heap, and half the passengers simply jumped out and escaped? In terms of risk, fatality, and compared to aircraft of the day, it was surprisingly good. And the huge raging fire and prominent news footage of it being caught on camera did it a bit of a disservice. By comparison, look at Wikipedia's list of worst aircraft crashes[3], and see how many are marked 'no survivors'. What if some of those "flew into a mountain", "engines failed", "mid-air-collision" had been captured on video in the earlier days of aviation, would we still have widespread planes?

[1] https://www.boredpanda.com/blog/wp-content/uploads/2019/02/i...

[2] https://www.boredpanda.com/blog/wp-content/uploads/2019/02/i...

[3] https://en.wikipedia.org/wiki/List_of_deadliest_aircraft_acc...

(NB. people now want aircraft which can legally be pushed horizontally by hydrogen, but cannot legally be pushed upwards by hydrogen.)

Re: Cargo airships could be big

#67

Post by foobarian »

marcosdumay wrote: post #54
twawaaay wrote: post #32

Earlier quoted context omitted.

Venus has plenty of atmosphere above the surface, but not above the point where there is 1 ATM of pressure. In case of Earth most of protection comes from our magnetic field. The reason is that magnetic field sweeps ALL charged particles coming from the sun while atmosphere only stops some. When a particle drops into atmosphere it has a chance to collide with an air molecule, the deeper the higher the chance. But the…

It has about as much atmosphere above the point where the pressure is 1ATM as we have on Earth. And no, we don't know if Earth's magnetosphere ever filters most of the incoming radiation (we don't such good measurement of the incoming radiation), what we know is that at sea-level, our atmosphere alone is enough. AFAIK, every time we measure it better, the effectiveness of our magnetosphere decreases. But it can only…

There is also probably a range of viable pressures so going down to multiple ATM would still work and provide more shielding.

Re: Cargo airships could be big

#68

Post by vintermann »

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?

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 three ships in the Goodyear fleet, though, as far as I know completely on schedule, which is rare in any project of that scale, let alone an airship project.

I still haven't written off Sergey Brin's project entirely, although it keeps getting delayed. Airlander I'm less optimistic about, but they did fly (and crash) their prototype and they're still around, so who knows.

Re: Cargo airships could be big

#69

Post by btilly »

black6 wrote: post #61
greesil wrote: post #57

Earlier quoted context omitted.

I don't understand this. LH2/LOX typically burns on the rich side to increase exhaust velocity. This means more momentum for less mass, which is what you want from a rocket. This is the opposite.

John Clark goes into detail in his book Ignition! about why smaller, lighter exhaust molecules are much better than larger and heavier ones.

John Clark also was the one who proposed adding mercury. It was a joke, that the military types didn't realize was a joke.

Read https://library.sciencemadness.org/library/books/ignition.pd... pages 193-196 in the PDF for the full story.

Re: Cargo airships could be big

#70

Post by innagadadavida »

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?

If US, China and Taiwan situation escalates and US imposes a naval blockade, this can be used to effectively circumvent it. Perhaps China should invest in this.
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