[HN Gopher] Cargo airships could be big ___________________________________________________________________ Cargo airships could be big Author : Luc Score : 243 points Date : 2023-01-30 14:24 UTC (8 hours ago) (HTM) web link (www.elidourado.com) (TXT) w3m dump (www.elidourado.com) | jp57 wrote: | 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? | vintermann wrote: | 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. | onlyrealcuzzo wrote: | 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. | .. | SonicScrub wrote: | Direct weather control is the prerequisite technology for at | scale operation of commercially viable airships. So once we | crack that I'm sure we will see them! | jodrellblank wrote: | We have very good weather prediction these days. After the | Titanic sank and people argued about mandating lifeboats on | ships, one of the arguments against was that global shipping | had already settled into the least stormy most safe sea | routes and accidents where lifeboats might help had reduced | year on year because it was already in everyone's interests - | cargo sellers, shipping industry, passengers, insurance | industry - to make that happen. | nradov wrote: | We have very good weather prediction for _tomorrow_. For | longer airship trips like spending a few days crossing the | Pacific Ocean the exact tracks of storms are harder to | predict, and dangerous squalls can brew up with little | notice during certain seasons. | innagadadavida wrote: | 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. | pphysch wrote: | China has been investing in (non-sea) logistics routes for | over a decade. It's called the Belt and Road Initiative | (BRI). | | To be clear, developing sea routes is also an aspect of it. | padobson wrote: | 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. | stopping wrote: | Or a single tracer bullet, if it's filled with hydrogen. | chatmasta wrote: | Surely you could design some redundancy into the hull? | It's not like the ship needs to be one giant gas bubble. | It can be a mesh of a few hundred bubbles that could each | pop without bringing the whole thing down. | natpalmer1776 wrote: | So... 100 tracer bullets instead? | AlgorithmicTime wrote: | [dead] | LarryMullins wrote: | Now you've got me wondering if composite frame airships could | be made transparent to radar. | hguant wrote: | I know some of the Canadian provincial governments were looking | at using airships to provide a means of supplying some of the | more remote northern towns - because of weather/terrain | conditions, you can't build a rail head that far north, and the | roads aren't reliable, so light cargo planes are the only | reliable means of getting goods around. Airships, even of the | good year variety, would be far cheaper for the weight/volume | transported, but initial costs were prohibitive, if I recall | correctly | mastax wrote: | How do airships fare in bad weather? | 0xffff2 wrote: | Not very well. [0] | | [0]: https://en.wikipedia.org/wiki/USS_Akron | worik wrote: | An extreme example. One extraordinary event is not very | good evidence. | | The safety record of the Zepplin company in Germany is | very impressive | | They had many failures, no fatalities. Until the | Hindenburg | jcranmer wrote: | The USS Akron, USS Shenandoah, and USS Macon all failed | due to bad weather. That's 3 of the US's 4 operational | airships. (Another airship was constructed for the US, | but was destroyed by poor handling before it was | delivered to the US.) | | Of the British experience with airships, R101 outright | failed due to bad weather, and three more were scrapped | after suffering accidents during bad weather, out of a | total of 16 completed. | | I don't feel like totting up the record of the Zeppelins, | but the Wikipedia page does indicate that several of them | failed due to weather incidents. One of the big lessons | from the most notable airship failures is that airships | _don 't really work in poor weather_, and safety in such | conditions means "don't even attempt to fly," which is a | pretty different rule than the one for airplanes or other | modes of transportation. | lesuorac wrote: | I mean if the alternative transports also don't work in | bad weather I'm not sure you can use some failures to | disqualify airships. | | So long as they work "more" days of the year it's a | better solution. Weather doesn't really sneak up on us | anymore. | hef19898 wrote: | No, the airship renaissance _was_ over a decade ago. | Cargolifter tried, and failed. From what I heard so, the water | and holiday park they built in the ex Cargolifter hangars has | to be quite good so. | jodrellblank wrote: | 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.) | [deleted] | Jean-Philipe wrote: | I completely agree. In addition to that, the Nazis neglected a | lot security measures that this aircraft actually had in place. | There's a nice episode of "well there's your problem" on the | Hindenburg: https://www.youtube.com/watch?v=chlF5oubFHU | LarryMullins wrote: | Everybody always focuses on the Hindenburg, but it's not as | though helium airships were much safer. In some scenarios they | were _marginally_ safer, but the deadliest airship disaster of | them all was the USS Akron, a helium airship. 73 dead and 3 | survivors, vs the Hindenburg 's 36 dead and 62 survivors. | | As for marginally safer: There were some cases of helium | airships breaking up due to weather and people surviving the | ride to the ground on still somewhat buoyant sections of the | destroyed airship, whereas that was less likely with hydrogen | airships because the wrecks would also burn. Compare the crash | of the USS Shenandoah to the British R101; both were destroyed | by bad weather but R101 had far fewer survivors because the | wreck burned. But even with helium, airships are still very | fragile and dangerous. Using helium isn't truly a panacea to | the hazards of airships. | jodrellblank wrote: | Even with the Akron, we're focusing on the first disaster and | not on the improvements or possible improvements since then. | | Akron crashed into the Atlantic in April. " _Most casualties | had been caused by drowning and hypothermia, since the crew | had not been issued life jackets, and there had not been time | to deploy the single life raft._ " | | Followed by: " _Macon and other airships received life | jackets to avert a repetition of this tragedy. When Macon was | damaged in a storm in 1935 and subsequently sank after | landing in the sea, 70 of the 72 crew were saved._ " | | The R101 was a stupid tragedy - they designed and built it, | then extended it, then launched the first flight without | sufficient testing to learn how the extension had gone and | how it handled after, in poor weather conditions, because the | launch date had been decided by politicians as a piece of | propaganda about reaching the far corners of the British | Empire by airship. | LarryMullins wrote: | > _Followed by: "Macon and other airships received life | jackets to avert a repetition of this tragedy. When Macon | was damaged in a storm in 1935 and subsequently sank after | landing in the sea, 70 of the 72 crew were saved."_ | | Yeah, but notably they hadn't solved the problem of wind | tearing airships apart. | | In the case of Macon they landed gently and in warm water, | and lifejackets certainly helped. But a soft landing is by | no means a guarantee in any airship crash, and even with | most people surviving the Navy still lost their investment | in the airship because of some wind. Putting lifejackets on | an airship flying over water should be common sense, but it | only makes the airship marginally safer. It's hard for | airships to be viable when they're so prone to tearing | apart and falling out of the sky. | BolexNOLA wrote: | I think his point is that most of these are measurable, | concrete problems that can be solved or mitigated enough | to be considered "safe," in the same way airplanes have | all sorts of risks and issues we solved or mitigated to | make them safer than the cars many use every day. | LarryMullins wrote: | The way I see it, aircraft have become mechanically | reliable and airships could become mechanically reliable | too. But airships will always be structurally vulnerable | relative to aircraft. They're inherently very light with | very large surface areas and there's no way around this. | snovv_crash wrote: | The strength to weight ratio of a carbon fibre | scaffolding would be far superior to steel. | bboygravity wrote: | Isn't the clothy stuff the problem though rather than the | scaffolding? | | Same on most sailboats: what makes them get into trouble | is not the hull cracking but rather the sail tearing up | in a storm or the mast snapping off and making them | uncontrollable / sink. | | (Im guessing out loud here, statements probably wrong) | aintgonnatakeit wrote: | If the clothy bits tear on a sailboat it's an | inconvenience. When the hard bits (eg keel) fail, it's a | problem. | zztop44 wrote: | Mast snapping happens. Rudder snapping off is also bad. | Often the issue is running into rocks/a reef due to a | navigation failure. Sails do tear, but for sailboats I | don't think it's as simple as the clothy bits being the | main weak point. I don't know about airships though. | worik wrote: | > But even with helium, airships are still very fragile and | dangerous. | | True. But with high speed landing and takeoff aeroplanes are | extremely dangerous too. | | Thousands of gallons of high octane fuell in the tanks on | board does not help | criddell wrote: | > high octane fuel | | Doesn't jet fuel have a relatively low octane rating | compared to most liquid fuels? | impossiblefork wrote: | Yes, but this octane-fire mixing is a bunch of confusion | to begin with. | | Gasoline is less ready to ignite than diesel~=jet fuel, | but has fumes. | | Diesel~=jet fuel has little fumes, but is easier to | ignite by heat, i.e. in an engine, but it will almost | never be ignited outside of an engine. Meanwhile, | gasoline is hard to ignite with heat and pressure in an | engine, but easier to ignite in air than diesel. | | Octane also has a higher boiling point than for example | heptane, so higher octane fuel is probably not related to | easy of ignition due to the fumes either. | LarryMullins wrote: | Yes, but I think he's using it in the colloquial sense | that means "highly energetic". | bruce511 wrote: | It depends on the plane, but both your point and the | parent point are correct. | | Piston engines run on high octane gasoline (Avgas) . This | is the stuff that powered planes up to, and just past, | ww2. Today it's still used in planes from that era, and | some smaller general aviation planes. | | Jet fuel (jet a1) is basically paraffin. All turbine | engines (think "jets", but also turbofan etc) run on | this. It's a lot less flammable than Avgas, but, well, | still makes a big bang if you fly it into a mountain. | | In short both are dangerous because they are high-density | liquid energy. Hydrogen is also dangerous, and there does | appear to be a double standard here. | throwaway894345 wrote: | > Hydrogen is also dangerous, and there does appear to be | a double standard here. | | I don't have beef with hydrogen, but I suspect it's a lot | easier to secure fuel in a liquid state versus a gaseous | state. Putting a lot of hydrogen in a relatively small | steel container for use in an engine seems quite a lot | safer than putting it in a big bubble and then dangling | people from it. But I am not an aerospace engineer, could | be wrong, etc. | avereveard wrote: | You can dump plane fuel before an emergency landing, | making the whole process safer. it's not just double | standards. | credit_guy wrote: | There's actually no need for hydrogen. Helium would do just | fine. From the blog post, filling the hypothetical airship with | helium would cost $8 MM, while filling it with hydrogen would | cost only $100k. Sounds like a no brainer. But, the overall | cost of the airship would be at $100 MM. Hydrogen would result | in a less than 10% cost reduction. | | Now, the FAA approved unleaded jet fuel in 2022. Yes, that's | how conservative FAA is. We'll sooner achieve world peace than | the FAA would approve hydrogen for airships. | kurthr wrote: | So, if filling your gas tank cost 8% of the price of your | car... you'ld think nothing of it? Lift gas leaks (esp He) | and gets vented. So this seems odd to me. It's kinda like | buying your car again every few months to a year or paying | $250/gal to fill up. Now 80x lower at 0.1% of the car price | you're in the regime where it's negligible like an EV. | LarryMullins wrote: | > _Lift gas leaks (esp He)_ | | Hydrogen more than helium, I believe. | kurthr wrote: | Each Hydrogen molecule is more reactive, but actually a | larger molecule (less leaky) because there are two (it's | diatomic H2 rather than monoatomic He). | | Now it does get complicated, because the simple atomic | radii aren't sufficient when you start bouncing around | and leaking through other materials, but suffice it to | say that He is still smaller once you look at the Vander | Walls attraction and everything. It may only be 10% | smaller, but that leads to at least a 20% lower leak | rate. | | https://bbblimp.com/2021/09/17/helium-vs-hydrogen-atom- | size/ | TylerE wrote: | Lift gas is a consumable. You have to vent it to descend in | many cases, and that's ignoring the inevitable leaks and | diffusion. | worik wrote: | > Lift gas is a consumable. You have to vent it to descend | in many cases, and that's ignoring the inevitable leaks and | diffusion | | Helium blimps compression the gas to lower buoyancy | tiagod wrote: | Preventing the helium from leaking out of wherever its stored | is challenging, it's not a "fill once and forget about it" | kind of deal. Helium is bound to get more expensive too. | jodrellblank wrote: | Helium is a non-renewable resource drilled out of the ground, | of which there is a global 'crisis' shortage[1]. Hydrogen is | easy to make in vast quantities and cheaper. But more | importantly, while they have similar lift capacities on paper | (Helium ~90% of Hydrogen), in practice they don't - | https://www.airships.net/helium-hydrogen-airships/ has an | explanation and calculations. | | Hydrogen lift airships set off fully inflated and vent | Hydrogen along the way for control of altitude and to stop | their lift cells expanding too much as they rise into lower | pressure air; Helium is too expensive to vent casually, so | they have to start less inflated to protect the lift cells, | and other concerns so Helium lift ends up with half the | payload carrying capacity, less fuel, shorter flight | distances. | | And, nb. the deadliest airship disaster was the USS Akron | which was was a Helium lift airship which crashed in a storm | with 73 deaths and 3 survivors. It's not as simple as | Hydrogen = danger, Helium = safe. | | [1] https://www.forbes.com/sites/omerawan/2022/11/10/the- | helium-... | pkulak wrote: | I wonder if you could use a fuel cell to get power from the | hydrogen you'd otherwise vent. | triceratops wrote: | If fusion power takes off, could you produce helium as a | by-product? | jerf wrote: | Basically, no: https://www.jerf.org/iri/post/2922/ | | And that assumes perfect capture, too. | | If you're going that route it'd probably be better to | just use hot air with the energy. | jasamer wrote: | Probably, but the amount would be tiny. ITER is trying to | generate 500 megawatt from a half-gram of hydrogen. | mpwoz wrote: | There's a fusion startup called Helion near Seattle | working on this, it'll be really exciting if it pans out | at scale. | | This video was a fascinating watch: | https://www.youtube.com/watch?v=_bDXXWQxK38 | aae42 wrote: | if we figured out fusion, it would alter the economics of | all of this | | why not fusion powered ships/trains/airplanes | worik wrote: | > why not fusion powered ships/trains/airplanes[?] | | What could possibly go wrong? | jasamer wrote: | Afaik what makes fusion hard is maintaining the | conditions that allow fusion to occur. Because of this, | it's quite safe - if anything goes wrong, it'll just stop | working. | chrisco255 wrote: | We already have fission powered ships and submarines. | jodrellblank wrote: | We almost had fission powered airplanes and airships: | https://en.wikipedia.org/wiki/Nuclear-powered_aircraft | | and https://en.wikipedia.org/wiki/Lockheed_CL-1201 | | And dreams of fission trains: | https://twsmedia.co.uk/2020/05/09/atomic-trains/ | moffkalast wrote: | Yeah hydrogen sounds like it could even be safer given that | you get a larger buoyancy buffer to fight downdrafts? It's | a real public misconception that it just explodes from all | those oxyhydrogen experiments at chemistry class, but pure | hydrogen such as in airships just slowly burns, much like | any other fuel we fill our planes with. | | The main problem is still that you need to contain a large | volume, which will inevitably get pushed around by wind | more than you can compensate for. | mikepurvis wrote: | As a noble gas, helium can't be synthesized, so its cost is | because of its scarcity-- and because it's a small molecule | (like hydrogen), you inevitably lose some and require | continuous top-ups. | | None of this sounds like it would be realistic at scale, no | matter the amount of money in play. | BeefySwain wrote: | You may have overlooked the part where filling the quantity | of airships that would (theoretically) be used would | represent over half of the KNOWN quantity exploitable on | earth, and would take decades to produce at current | production rates. Also, they would need topped up over time. | Compared to hydrogen, which is cheap, available, and | renewable. | credit_guy wrote: | > KNOWN quantity exploitable on earth | | It's great that you emphasized "known". | | Knowledge is not a static thing. Also what's economically | exploitable is a variable thing. | | Currently, the US produces 40% of the world's helium, | despite producing only 25% of the world's natural gas. Is | it because the US has drawn a lucky lottery ticket for | helium? | | That's very unlikely. Helium is being produced continuously | inside Earth as the alpha particles generated during the | radioactive decay of some elements (mainly Uranium and | Thorium, but Radon too). It seeps upward, and it generally | escapes in the atmosphere, but some of it gets trapped in | the same geological formations that trap natural gas. | | In most places people don't bother to see how much helium | there is in natural gas. They just sell the gas and take | the money. Separating helium can increase the profitability | a bit, but it depends on how cheaply you can do the | separation. It's very likely that the US has better | technology than the rest of the world, and because of that | it separates more helium for the same quantity of natural | gas. | | As the technology will spread out, more helium will become | recoverable. | | Also, it may come as a tautology, but more helium is | economically recoverable if its price goes up. | dwighttk wrote: | Author mentioned a market for 25K of these airships, which is | like half the helium on earth the _first time_ you fill them | up. $8M will go up once you start building | kortilla wrote: | The FAA approved modifications to piston engines to use | unleaded avgas. Jet fuel doesn't have lead. | | Also, this isn't about the FAA just being slow for no reason. | Switching from leaded to unleaded without the engine | modifications was not safe for the piston aircraft that need | it. | | https://en.wikipedia.org/wiki/Jet_fuel | | https://en.wikipedia.org/wiki/Avgas | coryrc wrote: | It's not safe for us to be breathing. But that doesn't | matter to cheapskate rich private plane owners or their | regulatory-captured FAA. | kortilla wrote: | Nothing is stopping the EPA from banning it regardless of | what the FAA wants. The FAA doesn't regulate emissions. | LarryMullins wrote: | The really rich private plane owners all have planes that | burn jet fuel, which is always unleaded. The piston | planes are generally owned by "doctor rich" upper-middle | class people, who have political influence to be sure but | they're hardly the billionaires that might be known by | name to politicians. | | I think it's more likely that the FAA protects general | aviation because general aviation is part of the | professional pilot training pipeline. | coryrc wrote: | [flagged] | LarryMullins wrote: | > _Ah, if you 're only "doctor rich" then it's okay to | poison children!_ | | That's not what I said _and you know it._ | | > _GA is responsible for 50% of lead emissions!_ | | Little lead is emitted at all these days, because leaded | gasoline was banned in _almost_ all circumstances. So you | 're talking about 50% of "not much". I'd be happy to see | it banned completely since there are now viable | alternatives, but I think you're going a little bit too | hard with this class war narrative. | Johnny555 wrote: | The people that are below "doctor rich" just rent their | planes from the FBO, a cheap piston plane can rent for | $125-$175/hour. So you can get in a couple hours of | flying for what it costs a couple to go to a football | game. | mabbo wrote: | > What if some of those "flew into a mountain", "engines | failed", "mid-air-collision" had been captured on video | | I'm now picturing how each of these situations would look with | airships. | | Most of them, in my mind, make a very nice "Boink" sound. | andrewflnr wrote: | My guess is the relevant sound is _rrrrrrip_. | flavius29663 wrote: | airships have multiple cells though, a single rip wouldn't | doom the entire thing | LarryMullins wrote: | But what caused the airship to rip? If it was wind, then | you now have that same destructive wind ripping through | the inside of your airship through the hole. | andrewflnr wrote: | I mean, I was specifically talking about the collision | scenario... | mikepurvis wrote: | Even still though, you'd come down to the ground for a | soft-ish landing (relative to a jet or helicopter, anyway). | evrimoztamur wrote: | Aircraft today are so safe because we had decades of | improvements in both engineering and safety regulations. I am | adamant that we could improve reliability and reduce potential | damage in accidents so as long as we apply the same principles | to airships. | LarryMullins wrote: | Aircraft survive because they're mechanically reliable, and | airships could also be made mechanically reliable. But | aircraft also survive because they're reasonably robust in | adverse environmental conditions. Airships aren't and never | will be, because they have to be built very large and very | light or they don't work at all. Furthermore airships are | slower and harder to hanger, which makes it even harder for | airships to avoid bad weather. Better weather forecasting | could help some, but keeping airships out of storms really is | of the utmost importance. | hedora wrote: | People often forget that the metallic paint used to coat the | Hindenberg is now used as solid state jet fuel. | nradov wrote: | I guess the last time was in 2013. Asiana Airlines Flight 214, | a Boeing 777 jumbo jet, crashed at SFO with only 3 fatalities. | Those are tough airplanes and low-speed crashes are often | survivable if passengers can evacuate before the inevitable | fire spreads. | | https://en.wikipedia.org/wiki/Asiana_Airlines_Flight_214?wpr... | | It was kind of freaky seeing the burned-out wreck sitting next | to the runway when I flew out of SFO a few days later. | rootusrootus wrote: | I was going to say that the 777 isn't a jumbo, but it looks | like they're now calling it a 'mini jumbo'. Feelings of | inadequacy, I guess, compared to the 747. | VBprogrammer wrote: | Meh, terms like this are pointless. Completely arbitrary | where you put them. | | It's probably more sensible to use terms like wide body, | implying 2 aisles. | hackerlight wrote: | You have to multiply by the respective probabilities of both of | these things happening to arrive at the expected number of | deaths. 0.01*(35/97) would be significantly bigger than | 0.000001*(97/97), as a hypothetical example. | | That said, planes have had years of safety R&D which helps get | that number down to 0.000001, and maybe the same could have | been done with blimps if they were given the opportunity? | holyknight wrote: | damn, this concept is mind boggling | guruz wrote: | Germany's cargo airship project is now an indoor waterpark | located in Brandenburg (close to Berlin) | | https://en.wikipedia.org/wiki/Tropical_Islands_Resort | | (With rising energy costs, hopefully it can stay like this for a | while) | vintermann wrote: | One of Germany's cargo airship projects. I'm pretty sure there | have been more, but none got as far as Cargolifter (for cargo. | For more modest ambitions, the Zeppelin NTs out of Bodensee are | still going strong, 25 years on). | aeyes wrote: | Their argument is that it is less polluting because people | don't have to fly to have a tropical vacation. It seems to | work, they are constantly expanding. | | I went last December, the place was packed. Surprisingly I'd | say about 40% of the guests were foreigners. It's nice but I | don't know if I'd want to stay a whole week. | aidenn0 wrote: | Seems like Germans like to turn anything into a water | attraction (e.g. Kiesgruben)... | newaccount2021 wrote: | [dead] | cameronh90 wrote: | As the article says at the end, a key technology here is | automation. | | Lots of cargo isn't time sensitive, but paying a load of crew to | take shifts sailing it slowly over the Pacific will kill the | economic viability. Additionally, making it unmanned gets rid of | a lot of the safety concerns, especially if you're going to use | hydrogen and run them primarily over water. | | Still, hard to see the advantages compared to container ships. | waynenilsen wrote: | It seems about 2x faster plus overland capabilities should be | great for some use cases that currently depend on canals. | ChuckMcM wrote: | Zeppelin is still around : https://zeppelinflug.de/de/ | | (or more accurately it restarted) | sitkack wrote: | 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 | connect and unconnect the tether and the airship would be able to | be autonomous for period of time and reconnect. Or a small track | could be run just to connect the small tug needed to pull the | airship. | the_cat_kittles wrote: | this is kind of like the old idea of a tow-path. those work by | floating the cargo on the river and pulling it with horses next | to the river. I really like the idea of pulling cargo floating | in air with trains, since trains already exist, and its also | visually entertaining. im curious what the numbers would look | like, since trains are very efficient for each marginal mile i | think? also im not sure what you would do about a wind storm | haha. | MagicMoonlight wrote: | Trains can't cross oceans or cover long distances or | dynamically change routes | genderwhy wrote: | Trains can't cover long distances? Surely that's a typo -- | trains can cover incredible distances... | | And they can change routes within their network. So yes, | there's some cost to get train stations and tracks built, but | afterwards they can visit anywhere within the network and | carry a whole lot more than airships. | | Fair point on the oceans thing though. | carapace wrote: | I've been slowly and sporadically working towards making large | airships. Basically you make a large (like a square kilometer or | more) rigid kite (see Alex G. Bell's cellular kites) and add | enough drone guts to make it into a giant drone. Then you lodge | an Airstream trailer or something in it. | | I'm not an engineer, but the small models I've built make me | think that there's no effective upper limit on the size of these | structures. I think you could build a kite that girdled the | world, an arch with no pillars. | | I've got all the parts now for a first prototype, but I don't | have any room to build it, so I'm studying origami etc. to design | a folding version. It's a PITA but the designs are pretty: like a | blooming flower, (like | https://www.jpl.nasa.gov/edu/learn/project/space-origami-mak... ) | Someone wrote: | > Basically you make a large (like a square kilometer or more) | rigid kite (see Alex G. Bell's cellular kites) | | Those were incredible | (https://www.scientificamerican.com/article/alexander- | graham-...), but it would surprise me if you could scale them | up to a kilometer in size. | | Also, from that article: | | _"Aggregated rectangles increased kite weight faster than they | expanded wing surface area. Tetrahedrons kept the ratio nearly | constant."_ | | That _nearly_ makes me think that, even if you wouldn't need | stronger beams for huge kites, a huge number of kites connected | to each other would provide less lifting weight than the sum of | the lifting weights of the individual kites. | | > I think you could build a kite that girdled the world, an | arch with no pillars [...] but I don't have any room to build | it. | | Doesn't surprise me ;-) | carapace wrote: | > but it would surprise me if you could scale them up to a | kilometer in size. | | It's like the intuitive argument that heavier objects fall at | the same rate as lighter objects: throw two shoes off the | roof, if you tie their shoelaces together will they fall | faster? You start with N kites and connect them, each kite | retains its airworthiness and connecting them doesn't change | that. | | > nearly [constant] | | The ratio falls off much slower than lifts add as you get | bigger. | | > you wouldn't need stronger beams for huge kites | | I don't think so, because you're just connecting small kites | together, but you need to be flexible, or maybe modulate the | airfoils' area (maybe open/close like butterfly wings.) | | > a huge number of kites connected to each other would | provide less lifting weight than the sum of the lifting | weights of the individual kites. | | If you just make a ball or cube, sure, but that's optional, | eh? Most of my designs come out looking like modified 3D | Sierpinski gaskets. | Someone wrote: | > You start with N kites and connect them, each kite | retains its airworthiness and connecting them doesn't | change that. | | If you do that, you have N wires between the kites and the | ground. | | Keeping them untangled may be a problem. Your best bet | probably is tying them together and having only one thicker | wire towards the ground. | | Making sure each of those wires takes 1/Nth of the load | from the wind definitely will be a problem, even in a | perfectly stable uniform wind. If you can't guarantee that, | you'll have to make the wires a bit stronger than for the | individual kites. | | If you think "we won't need 1 wire for each small kite", | you'll need to make the connections between the kites | stronger. To see why, think of the similar problem of a | plank over a ditch. If a 1m plank over a 80cm ditch just | holds your weight, do you think a similar 25m plank over a | 20m ditch will hold you, standing in the center of the | plank? Do you think it will hold 25 persons along its | length? | xg15 wrote: | Ok, so I love his enthusiasm, but when someone proposes a | hydrogen/propane/ethane mixture as lifting gas and support struts | made of magnesium, I'd like a few more details on how to deal | with the problem of everything bursting into flames than "we'll | deal with the risk and do some clever engineering" :) | jacknews wrote: | There's no doubt they'll be big, but will they be practical, | economically viable and successful? | qikInNdOutReply wrote: | they could automate overseas transport of (e.g. fruit and other | time-critical) cargo, with no pilots and very much reduced | fligth costs, while being much faster then ships. Then off the | coast its remote take-over and steering towards the freight | air-port of destination. | | The critical part here is good enough automation to keep the | thing on track and prevent accidents, while not trying to | integrate it into the airways like a traditional plane. | | They might even over time grow into a "2nd class - slow - but | cheaper transport" for people in no hurry, but with limited | funds. | | PS: It failed before though.. | https://en.wikipedia.org/wiki/CargoLifter investors beware.. | nradov wrote: | It is highly unlikely that uncrewed cargo aircraft will be | allowed to operate in most US airspace any time soon. They | can't reliably see and avoid other aircraft operating under | VFR, and so are restricted to only limited designated | airspace. | | Airships are unable to cruise at high altitude due to loss of | lift, and are vulnerable to damage from severe weather. For | ocean routes it's not always possible to route around storms. | | People keep wanting cargo airships to be a thing for some | reason. It's not likely to happen. The costs are too high and | the range of potential applications too limited to produce a | real industry. At most we might see some limited military use | where cost is less of a factor. | mupuff1234 wrote: | Are remote crews an option? | nradov wrote: | Not an option under current FAA rules. The available | optical sensors are still generally inferior to human | eyes in terms of dynamic range, depth perception, and | slew rate. The US military does fly remote-piloted | aircraft (Predators being the most prominent example) but | they're only allowed to operate in limited pieces of | designated airspace due to the risk of midair collisions. | | Communications reliability and latency is a problem. We | still have no way to guarantee solid bidirectional comms. | The mishap rate for RPVs is much higher than for | comparable manned aircraft. | actionfromafar wrote: | If/when forecasts will be good enough to only dispatch and | route airships when they can be safely flown to either | destination or safe harbor, is the wildcard I could imagine | to make them viable options. But as you say, is the niche | large enough to make work? | | I think the pull for wanting them isn't so strange - they | offer the promise of much lower fuel costs, which is a big | stigma and problem of current aircraft. | nradov wrote: | The atmosphere is a chaotic system. How could forecasts | be improved enough to enable safe flights across the | Pacific Ocean during storm season? | | Concerns over fuel costs seem a bit silly as those are | only a fraction of air cargo costs. There are significant | fuel efficiency improvements already in the development | pipeline with lighter composite structures, higher aspect | ratio wings, open rotor turbine engines, and perhaps even | blended wing-body fuselages. | LatteLazy wrote: | I don't think you can send perishable goods via a very slow | and delay prone transport medium. More likely this can be | used for the opposite sort of goods: durable, low urgency | supplies. | bmelton wrote: | They are only 'very slow' when compared to aircraft, which | are kind of poor vehicles for transporting cargo in the | first place. | | A dirigible flying with the jetstream is almost twice as | fast as a cargo ship doing the same. | | I think they're impractical for lots and lots of other | reasons, and your "delay-prone" critique is probably | salient, but "slow" needs to be contextualized somewhat. | LatteLazy wrote: | Twice as fast as a cargo ship is still only 50kph right? | | And the Jet stream only goes one way and only West to | East (in the northern hemisphere) and only at certain | latitudes right? | | So if you're only competing against cargo ships. And you | happen to want to head East (only, no returns). And you | need to go faster than a ship, but not over 100kph. And | you are already at the right latitude and so it your | destination. And you're cargo is not going to perish any | time soon, and is not too dense, then this can work? | bmelton wrote: | You're exactly right, but perhaps missed that the trade | route you're describing is China to Los Angeles, which | alone accounts for $132 billion in trade every year, and | perhaps that cargo vessels allegedly account for 20-25% | of anthropomorphic carbon emissions. | | Also probably worth pointing out that airships going | _against_ the jetstream are still faster than cargo ships | which are also going against sea currents. | | I'll repeat my disclaimer again here, that "I think | they're impractical for lots and lots of other reasons" | but there is a definite benefit to cutting the carbon | emissions of the world's most popular trade route by 90% | and halving the time spent in transit even if you assume | that there are no other applications, which is probably | not correct. | hengheng wrote: | I'm not comfortable relying on these being crewless, I've | seen too many mobility projects die. When freight trains and | trucks can operate crewed, a cargo airship will have no | different rules to profitability. | traceroute66 wrote: | > 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, | yeah ... | | The trouble is that the present system already works well. | | If it's not urgent, you can put tons of it on a massive ship. | That ship can make multiple stops along the way. | | If it's urgent, you can put it on a plane. Modern airfreight is | reasonably efficient and not _that_ expensive. | | I really don't see what airships all bring to the party. Except | perhaps being a slow-moving target for miscreants and bringing | high-profile failures in newspaper headlines. | | As for the people who say combine AI + airships ... yeah, like | that's going to seriously happen any time soon. AI can't even | do FSD in a Tesla properly yet. Putting AI in an airship, in | today's complex busy airspace, add in real-life weather | conditions and real-life technical issues ... yeah, erm, thanks | but no thanks. | | [1]https://news.ycombinator.com/item?id=3000819 | jodrellblank wrote: | > " _I really don 't see what airships all bring to the | party_" | | Heavy lift. Put hundreds of tons of house(s) from a house | factory or skyscraper level(s) from a skyscraper factory on | them, airlift them to the building site around the country. | | Centralise most of the building work in one efficient scaled | up factory, deliver an enormous buildings quickly piece by | piece by air instead of slowly by having all the parts driven | around windy roads and through closed city streets and | assembled by a crews of people travelling to the building | site and home every day. | djtango wrote: | What about places with limited rail/roads like Alaska and | Kazakhstan? | ghaff wrote: | As I recall, about 1/3 of the population of Alaska is in | the vicinity of Anchorage which has a port and is connected | to Fairbanks by road. Juneau, the third largest city, is | also on the water--as are other cities in Southeast Alaska. | Many other cities--such as they are (the 4th largest city | in Alaska has a population of 20,000)--are also on the | ocean. | jcranmer wrote: | 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. | traceroute66 wrote: | > What about places with limited rail/roads like Alaska and | Kazakhstan? | | What about them ? | | If there's no cargo facility there already, then nobody's | going to suddenly turn up and build an airshipport (or | whatever you want to call it). | | The way modern day logistics works is like an inverse | pyramid, you fly/ship/train in bulk somewhere, and then you | go smaller and smaller scale to the remote/rural areas ... | right down to a man on a bicycle or whatever. | | Cargo airships, _IF_ they ever happen, are not going to | change the fundamental way modern logistics works. Basic | economies of supply and demand. Sending the man on the | bicycle will always be the cheapest and most sensible | option for remote areas where only a handful of people | live, especially if they live many miles from each other | (e.g. rural farming). | [deleted] | fiat_fandango wrote: | Iranian missile boats are going to have a field day with these... | Overtonwindow wrote: | Airships have one, tremendous problem: Hydrogen. Helium is too | expensive and is running out, and hydrogen, well see the | Hindenburg. There's a lot of research into "safe hydrogen" but | despite decades of research (and money) there has not been any | success. Until you can overcome the fizzy lifting gas issue | airships will remain a dream. | actionfromafar wrote: | Your not trying very hard to shift what's acceptable to talk | about. :-) | cityofdelusion wrote: | The article proposes autonomous unmanned cargo airships. Does | the world care about "safe hydrogen" in this application? Most | zeppelin disasters involved weather or mooring issues, not | fire, and usually injured crew/passengers, not ground crew. | oblak wrote: | CAPTAIN: All aboard for safety and adventure on the rigid airship | Excelsior, where the pampered luxury of a cruise ship meets the | smoothness of modern air travel. Yes, when you fly Excelsior, | you're flying in style and safety. | | TIMMY: Safety? But isn't hydrogen flammable? | | CAPTAIN: And how, Timmy. That's why Excelsior is filled with | safe, natural helium. Why, it's actually flame-retardant. | | TIMMY: Neat! | | CAPTAIN: And safe. So, whether you're enjoying excelsior's | majestic vistas, duty-free shopping, high-stakes baccarat, | dancing with your lovely wife, or even a cigar after a french | gourmet dinner, you'll be enjoying them in style and safety. All | aboard Excelsior! | rob74 wrote: | > _Second, some modes are missing because a lot of countries are | not connected by land. Looking at US import and export data, and | excluding Canada and Mexico where US roads, rail, and pipelines | connect, water transportation has claimed the majority of both | the tonnage and the value._ | | Er... what? Just because you can't ship stuff between _some_ | countries by land, they 're ignoring _all_ cargo shipped by rail | and truck internationally? Sounds like throwing the baby out with | the bathwater... | twelve40 wrote: | he says throughout the post that the main focus is | intercontinental cargo market | btilly wrote: | 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. But still not a great thing to do. | | For those who are puzzled at the mercury comment, energy is | proportional to mv^2/2 while momentum is mv. Mercury takes away a | bit from the energy, but increases the density, and therefore | gives you more momentum per unit of fuel. It is a great theory, | ruined by the fact that we'd be spraying nasty poisons | everywhere. | greesil wrote: | 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. | black6 wrote: | John Clark goes into detail in his book Ignition! about why | smaller, lighter exhaust molecules are much better than | larger and heavier ones. | btilly wrote: | 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/ignit | ion.pd... pages 193-196 in the PDF for the full story. | sitkack wrote: | One has to be really really careful when cracking these | kinds of jokes, one really has to weigh the downside of | it being taken seriously. | | I'll still do it, on an ephemeral medium, and then spoil | it seconds later. That is only way it can be delivered. | andrewflnr wrote: | The suggestion to use a magnesium frame, in combination with | hydrogen for lift, is kind of hysterical. Why _not_ use a | flammable metal with your flammable lifting gas? I won 't even be | shocked if it works, but it would still be a hell of a thing. | jillesvangurp wrote: | You need oxygen to get to the flammable material to burn it. | For magnesium that means grinding it to a fine powder that | burns really quick. Otherwise, it will just oxidize at the | surface and be quite boring and inert. It's a common metal used | for all sorts of engineering. E.g. German WWII era planes used | some magnesium parts. | | Iron also burns if you grind it to a fine powder. You can try | that out if you have some steel wool. It's just an exothermic | oxydation process. The more surface area the hotter it burns. | Magnesium just burns a bit hotter. Most of the colors in | fireworks are just different metal powders burning. | | And for hydrogen, you need to mix it with oxygen to get a | flammable mixture. So, a large mass of hydrogen is explosive in | the same sense that a few tonnes of kerosene is explosive. I.e. | not that much at all. Also, hydrogen is light. If you have a | leak you go down, and the hydrogen goes up very rapidly. It | doesn't stick around. | | They did this routinely in the 1930s. It wasn't much of an | issue then. The theories of what happened to the hindenburg | vary a bit but it seems as it didn't explode so much as burn. | Probably most of the hydrogen escaped before it could burn. | | https://en.wikipedia.org/wiki/Hindenburg_disaster | | Interesting read. Quite a few people actually survived. I'm | sure these things could be engineered to a much higher safety | standard now. | ambientlight wrote: | Great book on this topic: | https://www.cambridge.org/tv/academic/subjects/engineering/a... | billbrown wrote: | Great essay. How he failed to mention Hybrid Air Vehicles | Airlander is beyond me, though. | | https://www.hybridairvehicles.com/ | hnarn wrote: | If something doesn't exist, especially when it's something that | has existed in the past but no longer does, there's usually a | good reason for it. It's not a natural law, but it's a good rule | of thumb to use to initially question and defend a | "groundbreaking" idea. | | A quick search online tells me that ocean freight is about | $1.3/lbs and air freight is about $5.3/lbs. Since we already know | that "airships" would likely never be more convenient than | existing air cargo, their only way of succeeding is if they found | a place between 1.3-5.3 where the cost savings felt motivated to | sacrifice regular air freight, while being many orders of | magnitude better than ocean freight for that use case. | | Even if we're nice and call this a "new" technology rather than | what it actually is -- a tried and failed technology -- this | "new" technology needs to be many times better than existing | options either for cost or convenience (preferably both) to | offset the major penalty you will have initially due to the lack | of existing infrastructure; and we're not just talking about | airports and runways, we're talking about the entire network of | optimizations in logistics, maintenance and everything else that | have occurred during a century of practice. | | I'm just a guy with an opinion, but I very much doubt cargo | airships even have a small chance of being "big", unless someone | builds something absolutely groundbreaking that leapfrogs | existing air cargo solutions entirely -- for example in areas | like fuel efficiency, autonomy, or something else. | | Nothing is impossible, but if I was a very technical and | entrepreneurial person, this isn't where I would put my time. | bruce511 wrote: | I am also sceptical that airships will ever be big. | | They do have advantages over ocean freight (not everyone lives | near a major sea port, or any sea port.) I'm not sure if your | price includes road transport, or rail, depending on where you | are. Sea is obviously a Lao quite slow. | | Air freight is expensive, and also somewhat limited airports. | In some parts of the world there are lots of those, but most | freight travels to a major centre, then trucks etc. | | I see airships as more of a "trucking" compeditor. | Theoretically it can load and unload with minimal ground | infrastructure. And it can go places trucks can't go. | | Yet with all of that the killer problem (literally) seems to be | weather. It's hard to see how that problem is reliably solved. | dathinab wrote: | Starupable? | | TL;DR: Technical viable but I think it doesn't bring enough | benefits in enough situations to be a success in most areas of | the world. | | Yes, but uh risky. | | Close to where I live are old end/post WW2 above ground large | aircraft hangars you can buy/rent etc. | | So there had been airship startups, multiple times. | | I'm not sure if a single of them is still around. | | The main problem isn't a stable hull, or non explosive gas | anymore. | | AFIK: | | The main problem is that there are nearly always much much more | convenient solutions. | | Like they only make sense (due to economics,convenience) for | transporting things which don't fit easily on the road, e.g. huge | thing. Which also tend to be heavy so the airship need to be | huge. | | But airships are sensitive to wind and the bigger the more wind | can get a grip on them. | | And only being able to use them at top (wind) wetter conditions | where plains, trains and cars can go even with pretty bad wetter | is a major problem. | | Another use-case could be areas where cars can't go, but airships | can e.g. huge swamps, areas with a lot of folding, but likely not | mountain sides where there is no street be you need to transport | things, too. But how common is that and how many of that cases | could also be fulfilled with other "special" but more convenient | to use transports like larger drones. | legitster wrote: | > What we observe under these conditions is that, domestically, | most of both the tonnage and value of cargo is transported via | truck. Trucks are neither the fastest nor the cheapest mode of | transport, but they provide a great value proposition--you get | your stuff in a few days for much cheaper than air freight. | | I feel like this is a bit naive. The true competitor to trucking | is rail. But trucking is preferred because it's point-to-point | and you don't have to deal with intermodal connections. Airships | _would have these exact same problems_ (unless you invented some | way to build routes and drop off containers at specific addresses | - but then you are back to it being slow again!). | | So the only real market would be replacing container ships with | something slightly more expensive but faster. But even using his | own math - a fleet of 25,000 airships each with only a 500 ton | capacity, and each being twice as big as the biggest airplane | ever built - seems like a nightmare. All to only capture half of | the global shipping market! | 4wsn wrote: | I concede I might be totally wrong here, but the issue with | rail seems to be profitability. | | I live in (moved to) Europe, and the railways are far more | developed than in the US. But as far as I know, they all have | to be heavily subsidized by the governments to even function. | None of them operate with a true profit. Here in Germany, 2.2% | of the latest federal budget is to support the railways. This | is despite the railways being privatized (into a government | owned corporation). | | And while trucking is also subsidized to an extent, and it's a | difficult business, but people do successfully operate trucking | companies. | | Airships might have the same problems as rail does with | intermodal connections, but it's worth a try to see how the | profitability equation works out (in real life, not MBA-land). | | _Maybe_ it's feasible for large multinationals to run direct | routes between their warehouses, with trucks being used for | last-mile delivery. The only cost is operation; in comparison | with rail where the infrastructure is a constant sink, and in | comparison with trucks where the infrastructure cost is | outsourced to society. | nradov wrote: | You have it backwards. Cargo railways are more developed in | the US than in most of Europe. After the latest round of | industry consolidation, most rail companies are highly | profitable. | | Trucks pay most of infrastructure costs through fuel taxes | and registration fees. | 4wsn wrote: | Fair enough. I conceded I might be totally wrong because my | conclusion is based on casual observation of passenger | trains and their infrastructure rather than looking into | the industry. | | I could feasibly reach all cities and _most_ large towns by | rail in Germany. Sure, it's slow as heck if you're not | taking the express train with no transfers and few stops. | But the infrastructure is there. Whereas in the US there | are massive areas where the nearest train connection is | hours away. | | I assume there are factors with freight trains I don't know | anything about, and if they're as profitable as you say | then the infrastructure is actually very optimized for | profitability; if there's somewhere worth reaching, the | trains reach it. | nwatson wrote: | Not mentioned in the article at all: security. | | Unmanned airships over water at low altitude, and pirates with | drones. | theelfismike wrote: | agreed, a huge, slow-moving target for a bad actor to try to | shoot down | padobson wrote: | This. It was all I could think about while reading the piece. | The US Navy is capable of making the seas safe, but under | current political conditions I don't even see THAT happening | forever. | | To make this work, the air force would almost certainly have to | get in on the act, and that makes even less geopolitical sense. | badcppdev wrote: | They have a very small section on wind and don't seem to have the | word storm at all. | | Ships could be massive as well and far more fuel efficient if | they didn't have to be engineered to weather storms. | thworp wrote: | This is a nice theoretical summary, but it's missing an analysis | on why previous attempts at cargo airships failed (see | https://www.airship-association.org/cms/node/214 ). | elidourado wrote: | Did you read the whole thing? There's an entire section at the | end that talks about what current players are doing wrong, | while raising the question of whether even the suggested | approach is fundable. | thworp wrote: | That section is very short and very general when compared to | the rest of the very detailed analysis. I know a tiny bit | about the failure of cargolifter and their problem wasn't | just funding and market fit. They also had a big list of | technical issues, not least with making the damn thing at | least somewhat all-weather (still nothing compared to jet | planes). | dbrueck wrote: | 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) | | A vacuum (or near vacuum) would provide more lifting force per | liter, would not have the scarcity problem of helium nor the | safety problem of hydrogen, and assuming the thing that generates | the vacuum is transportable, it'd eliminate the need for separate | ballast. | | Edit: the wikipedia article cited by slibhb has all sorts of good | info - thank you for sharing that! | cdot2 wrote: | I suspect that the materials and engineering required to | maintain a vaccum would be so much heavier than the engineering | required to hold hydrogen that it would literally outweight the | benefit. | lordnacho wrote: | 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. | slibhb wrote: | That's a fascinating idea. I googled it and came upon | https://en.wikipedia.org/wiki/Vacuum_airship and https://schola | rsbank.uoregon.edu/xmlui/handle/1794/22370#:~:.... | | Sounds like it's feasible but a materials/engineering | challenge. | WorldMaker wrote: | One interesting modern wrinkle versus hydrogen is the idea of | using an H2 fuel cell for easy access to electricity (versus | lift) without needing to carry another electricity source. | lucideer wrote: | Wild wild speculation: I'd imagine "rigidity" is a trade-off | between weight and ability to withstand the given pressure | differential for any two gases (outside & inside). A vacuum | would undoubtedly give extra buoyancy but the additional weight | required to achieve rigidity might not make the trade off | worthwhile. | vel0city wrote: | I'd imagine its because its one thing to make a basic rigid | shell (able to hold its own weight without collapsing) and | another thing to make a giant pressure vessel able to withstand | immense pressures. Imagine a storage tank made out of glued | together popsicle sticks with a plastic bag around it versus a | CO2 cylinder. One is going to weigh quite a bit more than the | other, all because one is trying to fight some massive pressure | differentials while the other can accept near ambient pressures | on both sides. | oliveshell wrote: | I looked into this a while back, and there's simply no feasible | way to construct an airship from known materials that could | sustain a vacuum of the necessary volume without being crushed | by atmospheric pressure. | | You can keep reinforcing the vacuum chamber, but by the time | it's strong enough, it'll be too heavy for the buoyant forces | to lift it. | brunoqc wrote: | Crashes would be spectacular too... | dwighttk wrote: | I started skimming towards the end but does the author get into | how the speeds are airspeeds, not ground speeds? | killjoywashere wrote: | His fundamental assumptions are flawed to the point of hilarity. | The same physical laws apply to ships, but they are at an | interface with a fluid with a much higher specific gravity | (orders of magnitude higher), so you can pack enormous amounts of | cargo on a ship. Once you have to solve the last mile, you need a | truck anyway. For the in-between, trains work great. | | Why, why would this make any economic sense? | SmooL wrote: | As the article states, the idea is that this would be faster | than ships, as well as operational in areas without large | bodies of water. | tim333 wrote: | I remember in the UK Airship Industries tried to make the things | work economically for ages but never did. | https://en.wikipedia.org/wiki/Airship_Industries | | For one thing they struggle a bit when it's windy. | netsharc wrote: | It'd be fascinating if the package tracker of the future says | "package delayed, waiting for a north-easterly wind from Los | Angeles. Meanwhile those mangoes from Africa are arriving | sooner!" | rsynnott wrote: | Partially or completely wind-powered cargo ships appear to be | on the way, so this might happen anyway. | vintermann wrote: | 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? | TillE wrote: | Birds are extremely light. Hollow bones, etc. | nradov wrote: | We've been able to manage the same even without | microcontrollers. Radio controlled model gliders and | sailplanes have been popular among hobbyists for decades. | I see them flying at a local park all the time. | onion2k wrote: | _For one thing they struggle a bit when it 's windy._ | | If you could move your airship to an altitude where the wind is | going in the direction you want to go that would give you a | huge advantage. | nradov wrote: | Airship cargo capacity is inversely proportional to ambient | air pressure. As they climb they lose lift, and while it is | technically possible to build an airship that can fly above | the weather the cargo capacity would be so low as to make it | pointless. | [deleted] | jliptzin wrote: | 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). | af3d wrote: | Imagine our supply chains being dependent upon fleets of | zeppelins. Sheesh... | recursive wrote: | They'd pretty much have to be. | comfypotato wrote: | I wonder why they didn't mention simply sailing with the wind | almost entirely. My understanding is that at certain altitudes | there are winds that circle the earth (the jet stream, yes?). If | the ships are completely autonomous, this could take a sector of | the market where shipping speed doesn't matter. It's a different | value proposition than discussed, but if I'm reading the | surrounding literature correctly, it's winds that have been the | main problem with this approach in the past. | rootusrootus wrote: | They did. It's a long article, they don't get to that point for | a while. Search the page for "The other approach would be to | take a deliberate strategy of riding the winds." | haarts wrote: | From the article I understand that airship can only fly so high | (I think because of the density of the air decreasing when you | go higher). A jet stream (10km+) is far too high for an airship | to reach (1.5km). | thrill wrote: | An airship can be designed to fly to over 100,000 ft, so you | could design anywhere in between. Above 60,000 feet the | average wind speed drops to 20 knots or so. | twelve40 wrote: | I didn't understand the jump from: | | > International water transportation is also cheaper than | domestic, perhaps around 1C/ per ton-km | | to: | | > Let's say airships captured half of the 13 trillion ton-km | currently served by container ships at a price of 10C/ per ton-km | | Having half of the entire market switch to something that is 10x | more expensive? | rootusrootus wrote: | There is a large dichotomy between the value of goods sent by | plane vs ship, almost certainly due to the trade-off on speed. | The intent with the airship idea seems to be to make something | roughly similar in price and speed to trucking on land, but | over the ocean. There is arguably a big chunk of cargo that | would like to be in that middle area. | [deleted] | TylerE wrote: | Why airships, a known failed technology, rather, than, say, a | large hydrofoil/catamaran, tech that has been proving quite | successful on long distance ferries for decades. | | The Hindenberg-class Zeppelins had the theoretical lift | capacity of approximately... 8 40ft containers. | mike-the-mikado wrote: | Electric cars were failed technology for about a hundred | years. But with better battery technology, combined with a | need to reduce carbon dioxide emissions, they are the | future. | | If something can only work effectively at huge scale, there | are likely to be a number of enabling technologies needed | to get there. | nradov wrote: | Y Combinator portfolio company Boundary Layer Technologies | tried to build a hydrofoil cargo ship to target the market | niche that wants to go faster than a regular cargo ship but | doesn't need aircraft speeds. The basic technology probably | would have worked but I'm skeptical whether the market | really exists. | | https://techcrunch.com/2022/06/01/boundary-layer/ | splitrocket wrote: | 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... | blamestross wrote: | Hang on tight for those gentle 185 mph breezes... | wefarrell wrote: | Only a problem if you're anchored to the surface. Otherwise | it's the changes in windspeed that you have to watch out for. | actionfromafar wrote: | A respirator and a teflon suit to keep the sulfuric acid clouds | away from your skin? | lkjdsklf wrote: | sure teflon might not be the most comfortable, but think of | the speed we could get on a slip n' slide | meindnoch wrote: | And what are we going to do there? Mine sulphuric acid from the | clouds? | haarts wrote: | Enjoy the view obviously. Cruise! | hutzlibu wrote: | In case that wasn't sarcarsm - you won't see much, as you | would be inside the acid clouds. | andbberger wrote: | what are we going to do from mars | ben_w wrote: | Everywhere but Earth is really inhospitable, but if it were | up to me, I'd pick the Moon first, then Mars, then some | asteroids, then _way_ down the list -- after we 've got | space industry sufficient to make planet-sized mirrors -- | _then_ I 'd pick the planet where the surface-level | condensation is lead vapour in an acid pressure cooker. | hutzlibu wrote: | The one big thing that Venus has, and every other option | does not - is earthlike gravity. That is a big deal, so I | am all for exploring options of terraforming Venus to | remove that acid somehow, because despite as Space | enthusiastic as I am - living inside hot acid clouds is | also not my dream. | kspacewalk2 wrote: | 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. | ben_w wrote: | 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. | kfarr wrote: | Yeah but iirc because of atmospheric density it's not | crazy to build a floating habitat. At least no crazier | then the tech required to get a crew and equipment to | Venus in the first place | elihu wrote: | Tourism, mining high value minerals for Earth, mining low | value minerals for construction on Mars, manufacturing | rocket fuel so that Mars can be the gas station for ships | headed for the asteroid belt (enabling more high value | mineral mining), low-gravity retirement communities for | people with mobility issues who would be wheelchair-bound | on Earth, real estate speculation, movies, sports, | manufacturing space infrastructure (easier to launch things | into orbit due to lower gravity), and basic science. | einpoklum wrote: | If I were living on Mars, I would absolutely not be | willing to let the rare minerals get sent up into space | then down to Earth. Learn to recycle, damn lazy Earthers. | gridspy wrote: | I think you'd appreciate the complex manufactured items | and goods requiring plastics that only Earth can export | to you. If tons of mined materials or produced goods | thereof were the cost, you would be keen to pay it. | unsupp0rted wrote: | Build a second basket for our eggs. There are obviously | better baskets than Venus though. I'd sooner choose an | orbital habitat. | LarryMullins wrote: | Tie things to string and dip them into the acid clouds. | Upload the results to youtube for profit. | [deleted] | ansible wrote: | Venus also does not have a magnetic field: | | https://astrobiology.nasa.gov/news/in-search-of-an-ancient-g... | | So baseline humans would still want radiation protection. | actionfromafar wrote: | TFA said the planet has a solar wind induced magnetosphere, | as well as is partially protected by the Sun from cosmic | rays. | marcosdumay wrote: | It does have plenty of atmosphere, so radiation isn't a | problem. (The problem is everything else, as usually is the | case on space.) | twawaaay wrote: | 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 there is always some number of particles that | were fortunate enough to reach far enough. Whereas magnetic | field is constantly acting on every charged particle and | deflects every single one of them. | | Only very highly energetic particles can cross magnetic | field and these tend to come from outside our solar system | and are very low in numbers. | | One thing we rely on atmosphere to take care is UV | radiation which is photons which is not charged which means | our magnetic field does nothing to it. Up to some energies | UV is easily caught even by very thing protective layers | (for example sunscreen!). It is not like you are going to | be showing skin on Venus anyway -- you are going to be | always enclosed with material that can stop UV, so this is | not an issue. Over certain energies we land in X-ray | territory and here our solutions are pretty limited but I | do not see a reason why Venerian atmosphere at 1atm should | be any more transparent to X-ray than ours. | marcosdumay wrote: | 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 stop | charged particles anyway, and air is very good at | stopping those. | foobarian wrote: | There is also probably a range of viable pressures so | going down to multiple ATM would still work and provide | more shielding. | Retric wrote: | 1 ATM of air is the same amount of material as 33 feet of | water which provides a great deal of protection from | charged particles. I doubt enough charged particles can | penetrate to the surface that it's a meaningful issue. | | I've seen many books etc suggest the earths magnetic | field is required, but I haven't found direct evidence | for it doing anything beyond protecting the ozone layer. | schiffern wrote: | >1 ATM of air is the same amount of material as 33 feet | of water which provides a great deal of protection | | "Amount of material" isn't what's relevant. It's closer | to "number of atomic nuclei." | | A certain mass of air is less shielding then the same | mass of water. By number density, air is mostly nitrogen | atoms, whereas water is mostly hydrogen atoms. Overall | this means that per kilogram, water contains 2.4x as many | atomic nuclei as air. | | -- | | Of course there are bigger problems with Venus cloud | cities. At the 50 km height where the pressure is 1 | atmosphere, the temperature is 75 degC (167 degF). At the | 55 km altitude where the temperature is 27 degC (81 | degF), the pressure is 0.5 atmospheres.[0] | | As a bonus, both these altitudes lie deep within the | layer of sulfuric acid clouds (50-80 km). | | [0] https://en.wikipedia.org/wiki/Atmosphere_of_Venus | Retric wrote: | Don't stop there. Charged particles in the solar wind is | mostly alpha and Beta particles. 33feet / 2.5 should stop | what 99.9999% ish of them? | | https://sciencedemonstrations.fas.harvard.edu/presentatio | ns/... | | Absorbing materials and their alpha particle penetration | depths. | | 5.5 MeV alphas: AIR(STP) 3.7 cm | | 2.3 MeV Beta: air 8.8 m | | Solar wind is even less energetic. | | Edit: "Auroral emissions typically occur at altitudes of | about 100 km (60 miles); however, they may occur anywhere | between 80 and 250 km (about 50 to 155 miles) above | Earth's surface." it really doesn't take much atmosphere | to stop it. | schiffern wrote: | Maybe true, but irrelevant. | | The problem is that 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 are correspondently much harder to | shield against. | | _Those_ particles are what ultimately determine your | shielding thickness. That 's true whether you're on | Venus, or Mars, or a space colony. | [deleted] | echelon wrote: | I've always felt people with these ideas are doing pie in the | sky thinking and missing the other trends that would beat this | concept out. | | Humans aren't suited for these environments. We evolved to fit | this planet. These gasses, radiation levels, terrestrial foods, | etc. | | The economics of going to Mars, Venus, etc. are iffy, and | humans probably won't enjoy being there. It's McMurdo times | about 1000. Getting back is hard. | | It's probably another hundred years before this is plausible | with our technology and willpower. | | You know what will do great in these environments? Robots that | don't have biological weakness. That don't need cellular | respiration or biochemical inputs. | | We'll probably have gotten really far with robotics and AGI in | those same 100 years. | | Basically, space will be inherited by our successors. | Artificial intelligences. Humans just aren't fit for these | environments. Robots and AIs are perfectly adaptable, though. | | Sci-fi sold us a fanciful picture of humans in space, because | that's a fiction that is pertinent to our experience and is | relatable. That isn't guaranteed. | kbenson wrote: | As long as the AI we create treat us with the love and | respect we treat our pets with, we'll colonize everywhere, | even if they have to clone us on site. | | Oh, the breeds we'll see... or be. | blamestross wrote: | If we go anywhere it will be spun-up asteroids. O'Neill | cylinders make more sense for a living platform than even | earth does. Once we actually have orbital infrastructure, | Planets are a horribly unsafe high-cost-of-travel backwater | to live on. | bobthepanda wrote: | I played a very interesting scifi game that solved the "how | do humans travel millions of light years" problem with "well, | they're actually clones produced at the destination planet." | I'd list the title but it is a pretty major spoiler. | shagie wrote: | I can't remember the name of the story, but I'm _pretty_ | sure that it was the last one in True Names and Other | Dangers. It was told from the standpoint of an intelligent | rocket ship that was launched because of an impending | calamity. That ship (and many others) were long shot "lets | see if we can find a life supporting world in the target | solar system." | | (late edit) - found it - "Long Shot" https://en.wikipedia.o | rg/wiki/The_Collected_Stories_of_Verno... | | > Description of a voyage from Earth to Alpha Centauri by | an automated, AI controlled colony ship. The ship is | launched as a "long shot" to preserve the human race | because the Earth is going to be destroyed by a rapidly | expanding sun. Ilse, the AI, carries human zygotes on a ten | thousand year trip to search for a suitable planet around | Alpha Centauri. Despite deteriorating hardware which causes | her to "forget" the entire purpose of the mission, she is | able to make inferences and use her remaining functional | components to complete the mission. Vinge states his | interest in writing a sequel depicting the lives of the | humans born on this world. | | Locations where it has appeared - | https://www.isfdb.org/cgi-bin/title.cgi?51200 | | It can be borrowed from archive.org: | | https://archive.org/details/collectedstories0000ving/mode/2 | u... | | https://archive.org/details/truenamesotherda00ving/page/n5/ | m... | the_af wrote: | Sounds very interesting, could you share the title anyway? | | I once had an idea to write a collection of scifi stories | with this premise, where every "seed" pod reaches a | different planet and each society of clones evolves | differently, providing a bunch of different stories related | by a "framing" story. | danbolt wrote: | I think it's _Mighty Kaiju Deimos_. | bobthepanda wrote: | That is a name of a piece of media in the game. | | It's 13 Sentinels Aegis Rim. It is like 90% visual novel | and 10% RTS. | the_af wrote: | > _It is like 90% visual novel and 10% RTS_ | | Ah! That's a pity. Visual novels infuriate me. But the | idea was cool :) | bobthepanda wrote: | I don't know that I'd call it a traditional visual novel. | Or at least not the kind with really trite stories. | | The way the story is structured, you unlock scenes where | you just read the text, and occasionally make branching | choices. But the scenes are not very long. | | It's also interesting in that it borrows from modern TV | non-linear storytelling; you do not see the story in | chronological order, nothing is as it seems, etc. If | you've seen Netflix's _Dark_ , it is pretty similar in | vibe. | danbolt wrote: | I'd say the RTS segments are closer to an action RPG as | well, such as Final Fantasy's ATB but on a kaiju/mecha | city map. | | Or, you could suggest that they're _Diofield Chronicle_ | 's structure with Nintendo-style puzzle development, plus | _Persona 5_ 's pop. | danbolt wrote: | You need to keep taking your medicine if you want to get | better, Juro. | jtrip wrote: | >Basically, space will be inherited by our successors. | Artificial intelligences. | | Ha ha, I love this. The sentiment has been there for a while | now in the zeitgeist but had been overshadowed and | outperformed by the lesser idea of 'Robots, and then AI, are | coming and they are going to get us!' Finally, I don't know | what section of human psychology is permitting it now, we are | slowly and slowly coming to the understanding that AI will be | humanity's child and will inherit the stars. | | I wonder if we'll, as in individual us humans, come along for | the ride or if we'll be laid to rest. Peter F. Hamilton and | his contemporaries like Neal Asher sure have interesting | thoughts on it. | xg15 wrote: | Still having a soft spot for some cyber/biopunk future where | we'll just eventually _become_ the machines - or be able to | bioengineer bodies which will be capable of overcoming those | limitations :) | SuoDuanDao wrote: | colonizing Venus with extremophiles that currently live in | Terran ocean vents might be a good humanitarian (vivarian?) | project. Life finds a way and all that, it'd be neat to | offset the current great extinction with a new cambrian | explosion on our sister planet. | dividedbyzero wrote: | Doesn't Venus have sulfuric acid clouds? Would that happen | above those? | twawaaay wrote: | It is much easier to construct a suit that will protect from | sulfuric acid than one that will protect you from low | pressure. | | The problem with pressure suits is that positive pressure | prevents the suit from being flexible, requires it to be made | from durable materials, makes doing anything very hard and if | there is any puncture you will loose the pressure | immediately. | | Sulfuric acid can be kept away with a tiny layer that covers | your entire body. Also, you will not die (immediately) if you | get a small puncture. Very minimal positive pressure is | enough to keep vapours outside of your suit even in case of | pretty large tear, giving you plenty of time to fix it. | MagicMoonlight wrote: | Finally people are waking up to the airship meta. | | I want blimpworld so bad. | atlasunshrugged wrote: | It's a narrow use case but I've always wondered if these would be | good for facilitating export of certain cash crops (or maybe even | processed critical minerals) out of hard to reach areas of Africa | where there isn't much infrastructure, rains can wash out roads, | and airports aren't conveniently accessible (thinking cocoa in | Liberia, cobalt in the DRC). | lastofthemojito wrote: | I think with my stomach too :) | | My first thought was "maybe cargo airships could make a | Pakistani mango supply chain more feasible". See: | https://www.eater.com/22618349/pakistani-mangoes-chaunsa-anw... | credit_guy wrote: | Great analysis. | | A few random thoughts | | 1. The dreaded helium leakage. It might not be a problem at all. | Think of a party balloon of the foil type. It stays afloat for | weeks. And it has positive pressure. A neutral pressure one would | leak much less. But maybe not to zero. Ok, now use a double | layer. Just like there are double hull submarines, this would be | a double foil balloon. The distance between the outer foil and | the inner foil would be only 1cm or so, so 99.9999% of the helium | would be inside the inner foil. The gas between the two foils | would in time become mixed with air, but the amount of double | leakage would be negligible. The weight of the double foil would | also be negligible compared to the overall weight of the | structure. | | 2. Going up and down. Hindenburg had a cruising altitude of 200m. | Up to 2000 meters or so, the air density goes down by about 1% | every 100 meters. So, lowering a balloon from 200m to 0m does not | mean you need to fully deflate it, only that you need to reduce | its buoyancy by 2%, or add 2% ballast. For a 1100 ton airship, | you need to add 22 tons of ballast. Pumping 22 tons of water 200 | meters high is not easy feat. But there's a cute shortcut: you | could send only 2.5 tons of hydrogen with a hose (hydrogen is | more than happy to flow up), and you burn it there. The resulting | water vapor needs to be condensed, but you can probably arrange | that with a small refrigeration unit that you power with the | electricity from a generator powered by the said hydrogen. The | current cost of hydrogen is about $5 per kilogram, so this whole | affair would cost you less than $15k. It's a rounding error when | you ship 500 tons of cargo. | | 3. Fuel. Yes, it would be cool to have neutrally buoyant fuel, | like a mix of methane and propane. But do you think the FAA would | like that? How is that different from just having some hydrogen | gas onboard, like, you know, Hindenburg? I think the most | conservative design choice would be to just use plain old jet | fuel. | SuoDuanDao wrote: | would batteries work for fuel in an airship? I know the battery | bank is a structural element in Tesla cars, seems like that | could be done with airships as well (it'd increase the price | precipitously of course) | rimunroe wrote: | > 1. The dreaded helium leakage. It might not be a problem at | all. Think of a party balloon of the foil type. It stays afloat | for weeks. And it has positive pressure. A neutral pressure one | would leak much less. But maybe not to zero. Ok, now use a | double layer. Just like there are double hull submarines, this | would be a double foil balloon. The distance between the outer | foil and the inner foil would be only 1cm or so, so 99.9999% of | the helium would be inside the inner foil. The gas between the | two foils would in time become mixed with air, but the amount | of double leakage would be negligible. The weight of the double | foil would also be negligible compared to the overall weight of | the structure. | | I assume someone else can address this better, but given how | expensive and limited helium is, I don't think we can just | write off losses by comparing airships to party balloons. Foil | party balloons look noticeably less inflated after a week or | two. I have no idea how much gas is being lost, but that seems | much more than a trivial amount to the point where I don't | think a second envelope is going to help you much. It will have | the same outgassing problems as the inner envelope, but will | add additional weight and air resistance, both of which will | reduce the maximum payload. Relatedly: is it cheap to extract | the helium trapped in the outer envelope? | | Given the quantity of helium needed for an airship fleet, is | topping them up regularly even an option? I'd assume it would | need dramatically more helium than is currently being produced, | and there's only so much helium available to us without using | something like hydrogen fusion. | | In college I briefly worked at Brookhaven National Laboratory | on an experiment with the Relativistic Heavy Ion collider. That | collider has a set of giant collection tanks next to it so that | (at least as it was explained to me) in the event of a | superconductor quench event, they can try to shunt all the | remaining liquid helium coolant into storage in order to limit | how much of the valuable resource they lose. I imagine the | amount of helium they're using would be peanuts compared to the | amount required for a cargo fleet. | credit_guy wrote: | > It will have the same outgassing problems. | | It will not. The outgassing is proportional with the | difference in partial pressure. On the outer foil the | difference in partial pressure is 1 atmosphere (only helium | inside, no helium outside). In time helium will leak out. Air | will probably not leak in, by you can add it, to maintain | equal pressure. The point is that you won't add a lot. Let's | say that in one year 5% of the helium gets replaced. | | That means the difference in partial pressure on the inner | foil is at most 0.05 atmospheres. The leakage will be much | lower. Most likely you would not need to refill the helium | inside the inner foil more than once during the lifetime of | the airship. | mark212 wrote: | 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. | ChuckMcM wrote: | The other point this obscures is that it pays scant attention to | wind profile. Specifically, if you're looking at 50 mph | transverse winds you aren't going to get to where you want with a | super big envelope/frame. Drag is the cube of airspeed, so the | bigger airships are, the less control you have over where they go | (without adding lots and lots of power to the power plant). | | Try off-loading containers when you're "ship" turns 90 degrees in | < 30 minutes because a breeze came up. ___________________________________________________________________ (page generated 2023-01-30 23:00 UTC)