8 ms·
Vacuum airship
- mlatu 3y agoi think the most promising research is atmospheric ionic thrusters. sure they have little to do with vacuum per se but if you could improve them enough to build a sort of cavity with lower pressure inside while providing upwards thrust, essentially directing air streaming into the cavity whereever you want to direct it to, you could both have your cake and eat it. it would be a very good insect trap and a highly efficient way to get rid of excess electricity quickly. perhaps you could also fix the ozone layer with this... ;)
- Sosh101 3y agoI wonder if such a thing is possible with modern materials?
- post-it 3y agoProbably, but you get a ~15% lift improvement over helium, and about half that over hydrogen. The returns are very diminished.
- mkl 3y agoIf you make it big enough, you don't even need the vacuum: https://en.wikipedia.org/wiki/Cloud_Nine_(sphere) https://en.wikipedia.org/wiki/Cloud_Nine_(sphere)
- jcahill84 3y agoWell that made for a really fun rabbit hole to start my day. Thanks. https://worldbuilding.stackexchange.com/questions/36667/can-cloud-nine-be-built https://worldbuilding.stackexchange.com/questions/36667/can-...
- MPSimmons 3y agoWhat's interesting to me is that nobody in that thread actually used a sphere the size that Bucky proposed. A sphere with a 1km diameter has a volume of 680,317,581 cubic yards. A sphere 1 mile in diameter has a volume of 2,854,543,238 cubic yards. The driving mass force per those comments seems to be the surface area of the sphere, which grows according to the square, but the lifting power grows by the cube.
- taneq 3y agoI think this is legitimately the first time in my life, that I've considered the squared/cubed law as a bonus.
- dr_dshiv 3y agoHydrogen reduces the lifting force of a pure vacuum by less than 10% and solves the problem of needing a stronger-than-diamond super lightweight shell. So, until you can make a shell with a mass less than the total amount of hydrogen, it doesn’t make much sense. I’d like to find calculations on the effect of hot/cold hydrogen on lift—might be a way to change the lift without releasing ballast or gas.
- Xylakant 3y agoThere is already a way to change the lift without releasing gas: pump the gas into a compressed container - it reduces the volume and thus the specific lift.
- WirelessGigabit 3y agoSo 1 kg of Helium in a balloon with a volume of 10cm^3 has more lifting power than that 1 kg of Helium in a balloon of 5cm^3?
- the_third_wave 3y agoLifting power is defined by the mass of displaced medium minus the mass of the displacing medium. Change your units from cubic centimetres to cubic metres and the answer is "yes".
- snewman 3y agoYes, although a better way of saying it is that it is not the helium which has lifting power, it is the balloon. A balloon has lifting power equal to the weight of the air displaced by the volume of the balloon. From this, you must subtract the weight of the balloon and its contents. Helium is one of the few materials that allows you to wind up with a positive net lift. (Also, for this to work, 1kg of helium would occupy a balloon much larger than 10cm^3).
- stetrain 3y agoYes, like how a 1kg 10cm^3 block of wood will have more buoyancy in water than a 1kg 5cm^3 block. Bouyancy “is equivalent to the weight of the fluid that would otherwise occupy the submerged volume of the object, i.e. the displaced fluid.” So compressing your lifting gas reduces the amount of air being displaced by its presence, reducing the buoyancy.
- deleted 3y ago[deleted]
- defrost 3y agoIn fiction (unmentioned in wikipedia article) There's a golden age of science fiction story whose author I don't recall that had a story hinging on surviving the crushing pressure of Jupiter's atmosphere. While putting it forward that no material could withstand a differential pressure of (Jupiter pressure XX atmosphere) | (Human necc. 1 atmosphere) a (fictional) solution was proposed of staggered shells, each reducing the pressure by 1 atmosphere (the amount required for a vacuum airship). I'll throw it out there for anyone to chase up or recall the story name + author. This reduction in stages notion is mentioned in the above article and it does prompt the question of whether a modern honeycomb material could be fabricated as a thick walled shell about a ballon shape with interior vacum and pressue reduction staggered through the honeycomb.
- Helmut10001 3y agoThis was in Hyperion Canthos, Dan Simmons! [Edit] after checking, it was not Jupyter that Dan Simmons wrote about, but the story sounded very familiar. Apologies.
- defrost 3y agoGood to know, cheers. Definitely not the story I'm dimly recalling though as I would have read it before 1982 as part of my (until then) ever expanding collection of tattered science fiction novels and anthologies. ( First book of the Hyperion series being published in 1989 )
- bjelkeman-again 3y agoSomething authors often ignore when writing fiction about Jupiter is the intense radiation there. You often see stories/games about astronauts doing EVA around Jupiter, but it is way more dangerous than the Van Allen Belts around Earth. https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Jupiter_s_radiation_belts_and_how_to_survive_them https://www.esa.int/Enabling_Support/Space_Engineering_Techn...
- defrost 3y ago
- animal531 3y agoI'm busy making an far future airship building management game where you have a little crew dropped into orbit of some kind of gassy planet, their mission to mine resources from the atmosphere and expand their ship, diving deeper and deeper as they pick up mass. I don't want there to be giant gas balloons obstructing the view and/or gameplay that's happening, so I'm using a zero point module that can keep the ship floating at a given altitude.
- taneq 3y agoNot to complain about zero-point-module based airships, of course, but you could do as the '90s isometric RPGs did with houses, and just not render the airships' lifting bodies.
- bshipp 3y agoAgreed, or only render the bags at full zoom and have them dematerialize as you move in for a closer look. That way you can easily find the airships on an overview map by their large sphere but still be able to micromanage the infrastructure as you zoom in.
- animal531 3y agoYou are correct, it is still an option. But at some point I will introduce some combat as well and I don't want the ship to have such an obvious weakpoint. It could be that I delay the combat at which point the player will have the option to have a honeycombed lifting body(/ies?) that can be armored or shielded in some way.
- ticulatedspline 3y agoYou're probably overthinking the realism. you do have prior art in all aspects though Zero Point - Skies of Arcadia Propeller - Final fantasy balloon with combat - Red alert 2 Kirov Airship will kinda depend on if this is 3d or not. if you're first person just shooting at the balloon portion, then yeah. go zero-point since profile will matter greatly. If this is an isometric or top down kinda game then like red alert you're just shooting a target not a piece of a target and you can just ignore damage to lifting apparatus (propellers or balloons) without breaking immersion.
- justinclift 3y ago> His patent application was eventually denied on the basis that it was "wholly theoretical, everything being based upon calculation and nothing upon trial or demonstration." The standards for what's considered patentable have certainly changed for the worse since then.
- dvh 3y agoThese days it's more like: for x in `cat /usr/share/dict/words`; do submit-patent "airship filled with $x" done
- dodslaser 3y agoMy airship is full of eels
- glumreaper 3y agoOutstanding comment! Bound to fly over the head of some in HN.
- appplication 3y agoIt’s an airship, it’s bound to fly over all of our heads. Unlike those pesky hovercraft.
- rascul 3y agoSorry, I can't help myself. https://mywiki.wooledge.org/DontReadLinesWithFor https://mywiki.wooledge.org/DontReadLinesWithFor
- adolph 3y agoOh hai, I see you are building a bike shed. You might consider a curl call over to OpenAI for all the method/apparatus/etc patent-talk.
- mywacaday 3y agoAlways make me happy to be reminded to look at myth busters https://youtu.be/kM-k1zofs58 https://youtu.be/kM-k1zofs58
- user070223 3y agoThough total vacuum is not that attractive, you could mix the idea with hydrogen/helium. My question is whether it's being used today, and how much would it cost / save Previous discussion https://news.ycombinator.com/item?id=8170569 https://news.ycombinator.com/item?id=8170569
- twic 3y agoWhat if you kept the envelope "inflated" using an electric field? Make it out of something conducting, insulate the outside, then charge it up. Self-repulsion will stop it collapsing. I leave the calculations as an exercise for the reader.
- nickpinkston 3y agoThis could be like an atmospheric Titan disaster if you get it wrong, but at least you could parachute out.
- csours 3y agoBut at 1 bar delta p, not 400 bar. Delta P means pressure difference. DO NOT GOOGLE.
- nickpinkston 3y agoSeems like it's easier to build a fireproof hydrogen design than get this right. Some of these proposed designs use an internal metal honeycomb for structural support, but an even lighter weight fireproof honeycomb could just prevent hydrogen leaks / oxygen mixing with honeycomb walls acting as "fire walls" and also reducing the extent of any leaks.
- BatFastard 3y agoCould you use a hybrid approach? Put hydrogen gas into a vacuum until the pressure the hydrogen exerted would offset the vacuum.
- csours 3y agoNow offering $250,000 rides to space on my carbon fiber vacuum airship.
- KMnO4 3y agoIt would probably be fine. The pressure under water is much much greater than in space. A submarine would be fine in space, but a spaceship would collapse quickly in the ocean.