9 ms·

SkyLifter is an eVTOL air crane

64 points by aggrrrh 5y ago

H8crilA 5y ago
This will be a pain in the ass to manage in controlled airspace because it's so much slower than anything else. But I guess it would also use different flight levels, so maybe not a problem at all. I wonder how does the fuel usage compare to a plane, that's the real measure of green-ness.
- doikor 5y ago
  Just fly it close to the ground and the only controlled airspace is near airports (and some big cities, military stuff, etc). Should not be that hard to stay out of those for the most part if you are transporting stuff like windmill parts to the middle of nowhere.
  - lstodd 5y ago
    If you fly low how do you deice the thing while avoiding terrain? Most of the crashes were due to flying into the terrain in adverse weather conditions after all.
    - doikor 5y ago
      Flying low does not mean "scraping trees" but for example Glass G airspace (uncontrolled basically) is everything under 1200' not near airports etc. For a lighter than air craft 1000 feet off the ground is quite a big margin of error actually. And I doubt one would be flying something like this in bad weather anyway. One would just wait for the next weather window. And one could easily take the ship into 4000' or something like that and still have minimal amount of other aircraft around once outside of airports (proper commercial jets fly at 40k feet or so).
      - lstodd 5y ago
        > 1000 feet off the ground is quite a big margin of error actually. Actually, no. It can't maneuver fast enough, it can't gain altitude fast enough. A downdraft or a squall and it's going into a hill or a tree from 1000ft in no time. Only good thing about lighter-that-air is that when they crash, they tend to crash slowly. Otherwise completely useless.
- krisoft 5y ago
  I think comparing it to a plane is misplaced. They call it a crane. Presumably the load and the craft arrives on a truck and you use it to hoist the load up the last few maybe hundreds of meter max. Do i read that wrong? Edit: yes! I was reading that wrong. To quote the relevant part: “SkyLifters fly from job to job, so they can do work in locations that would be challenging for land cranes.”
  - Already__Taken 5y ago
    If you rent a crane though you're also paying for the crew to drive the thing to you. This really has a chance of just auto-piloting over to the job to be then be run by an operator.
    - masklinn 5y ago
      You'll definitely be renting the crew. The skylifter website specifically mentions the one crew. And per my calculations the thing is the size of a cricket or baseball field, there is no way it'll be flying itself.
  - masklinn 5y ago
    > Presumably the load and the craft arrives on a truck Nah they're absolutely gigantic and usually semi-rigid (especially if you have solar panels on top). SkyLifter seems very cagey about the purported crane's dimensions (couldn't find anything on the subject), but the Airlander 10 (which I understand only lifts 14t) is 90 x 43 x 26... meters. IIRC the rule of thumb is that you need 1m3 of helium to lift 1kg, to lift just a 250t payload you thus need 250000m3 of helium. According to skylifter's "design" page the lenticular envelope has a height of 1/4th the diameter (3 units wide, 0.75 units deep). For a cylinder that's 108m wide and 27m high, so taking in account the lenticular shape we might be closer to 120m/30m (400ft wide by 100ft high). That's the size of a baseball field, and 14 stories high. And that's only taking the payload in account, not the solar panels, not the cabin, not the engines, ...
Thomaschaaf 5y ago
In germany there was a similar project the "CargoLifter" which sadly never succeeded: https://en.wikipedia.org/wiki/CargoLifter https://en.wikipedia.org/wiki/CargoLifter
- Roritharr 5y ago
  CargoLifter for me personally marks the beginning of the German Decline in Engineering. The reasons for why it failed are the same reasons why we have such large problems with infrastructure projects and are falling behind in innovative technology. It's a very sad read.
  - CoChiefResident 5y ago
    If I remember correctly, Cargolifter failed to have a straightforward loading and unloading method. The airship is designed to lift a certain amount of weight, which has to be replaced as soon as you dismount the cargo. Cargolifter used water which was transported to the destination site via trucks. I only had a quick glance at the SkyLifter website, but I did not find any solution for that problem.
    - capableweb 5y ago
      It seems surprising to me that there is not more information on the website regarding what gas this gas-filled lenticular-shaped aerostat thing is floating with. I understand they are aerostatic and the gas needs to be lighter than air, but that doesn't leave many options that are not helium I guess. And then in order to drop whatever they haul down, they'll need to either let it escape or contain it somewhere else, or spend energy at keeping it down somehow.
  - ck45 5y ago
    I have similar feelings about https://en.wikipedia.org/wiki/Transrapid https://en.wikipedia.org/wiki/Transrapid. At some point the whole project became too political and nobody wanted to be responsible to either push the project or pull the plug. Instead a ton of money was basically wasted.
0x_rs 5y ago
Lighter-than-air is still largely untapped territory today, and it's a shame because it should scale in size very well. Without going straight away into more ambitious projects that were fantasized the past century [0], I'd love for a resurgence of it. 0. https://en.m.wikipedia.org/wiki/Cloud_Nine_(sphere) https://en.m.wikipedia.org/wiki/Cloud_Nine_(sphere)
- masklinn 5y ago
  Tons of companies over the years have taken a shot at it (CargoLifter, Aeros, Walrus HULA, HAV). Turns out, so far, it's all been pretty shit, because outside of super specific niches airships are so slow they need to be much cheaper than aircraft, but the upfront costs to create massive-enough airships to even have a chance makes it a difficult proposition.
londons_explore 5y ago
Doesn't this type of craft normally struggle with any kind of wind? I can imagine that seriously hampers it's profitability when it can't be used 90% of the time because the wind threatens to be more than 10 mph...
wepple 5y ago
Can somebody explain to me how it is able to hover (suggesting it is neutrally buoyant in air) but then attach a load and overcome the weight?
- joenathanone 5y ago
  It can just swap weight(s).
  - Toutouxc 5y ago
    So instead of having to move your 25 ton cargo around, you now have to move your 25 ton ballast to be swapped for the cargo at the drop off point so the SkyLifter doesn't yeet itself into stratosphere. The FAQ and literally everything else about this project is vague, disappointing and a little fishy.
    - joenathanone 5y ago
      Cranes also use counterweights.
      - masklinn 5y ago
        Crane counterweights are a completely different matter. The crane doesn't have to drop the counterweight to take on load (the opposite really, unless it's a superheavy with active counterweighting the entire point is to be more stable once loaded). So the issue with this thing is, any time you move an actual load from A to B, you need to have a weight waiting for you at point B. Or to offgas at which point you won't be able to make a second trip without regassing.
        joenathanone 5y ago
        If the weights remain on the ground you can use a pulley system to load and unload weight, just put slack in the cable and lighten the load… Could even be automated with the right sensors.
lifeisstillgood 5y ago
I am trying to avoid being negative here but lifting 250 tonnes in remote / difficult areas is a serious challenge. The lift is not so much the problem (although that's a big balloon) - fighting wind sheer will require stupendous amounts of power. Especially as wind is pressing not just at that cargo but at the balloon itself. And anywhere that's remote / inaccessible almost always comes with lots of wind. Hmm, actually lift might be a problem ... So to get 250 000 kg off the ground takes a volume of helium balloon (if the below site is right) of 250,000m3 (it seems to be fairly linear) (this seems intuitive - air "weighs" about 1.2kg /m3 sea level, so a vacuum of 1m3 could lift 1.2kg. ) that is 100mx100mx25m ! that's the inner part of any athletic stadium. That's insane surely? https://www.engineeringtoolbox.com/hot-air-balloon-lifting-force-d_562.html https://www.engineeringtoolbox.com/hot-air-balloon-lifting-f...
- CraigJPerry 5y ago
  >> that is 100mx100mx25m That’s huge! I wondered how big was the hindenberg, wiki claims 245m long and 41m wide, and 41m tall (excl. cabin). Only 200k litres of gas capacity. 232k tonnes lift.
  - ixfo 5y ago
    So it is huge, but well within historic capabilities - and materials science has come a long way since then. I'm quietly hopeful for this.
    - ClumsyPilot 5y ago
      I think the difficulty is not that its a huge airship, its the precision required to use it as a crane.
      - CraigJPerry 5y ago
        That's an area i'd be quietly hopeful in. Assuming propulsion motors are available which are both: a) powerful enough to defend against wind acting against such a huge object b) responsive enough to change their thrust vector (power & direction) such that the associated PID loop can operate within some reasonable set point boundary Then there are already open source hardware and software solutions available for this - i'm not proposing someone slaps a pixhawk 4 on a huge airship and gets a few mates over to help tune the PIDs in Ardupilot - i mean that the know-how is there. Translating that into a product that would be suitable for controlling such an aircraft would be do-able. Certification costs and expensive hardware suitable to run it all on are a different matter. I guess this is a long way to say i don't think it'd be easy or cheap, but i don't think they'd have to make a break through innovation to make it possible.
davidhyde 5y ago
I'm calling bullshit on this. Slick marketing driven website, low resolution photos of actual prototypes, hand-wavy FAQ and no other technical details. They claim speeds of 40 knots but does that mean that can stay stationary in 40 knot winds (the same as traveling at 40 knots) or that it can hitch a ride on high winds? The wind forces on the balloon look they would be far too high for those tiny fans to counteract even with its flying saucer shape. And solar panels to power them? Come on! 250 tonnes is A LOT to lift. Look how big a hot air balloon needs to be to lift a few passengers in a basket. Sure helium has more lifting power but it doesn't create miracles. That means the balloon would have to be absolutely massive. Far bigger than the CGI renders they show on their site. Helium is very expensive and a lot of it will leak out of a balloon like that even if you can reclaim the bulk of it back at the storage site. I'd like to be proven wrong because the idea seems wonderful but the only thing they may be successful at doing is lifting some money from the hands of some gullible investors.
- masklinn 5y ago
  > 250 tonnes is A LOT to lift. Look how big a hot air balloon needs to be to lift a few passengers in a basket. Sure helium has more lifting power but it doesn't create miracles. That means the balloon would have to be absolutely massive. Agreed, per my calculations it'll need to be around 120m wide, and 30 deep (lifeisstillgood comes up with slightly smaller numbers of 100 x 25, possibly because they used 1.1kg / m3 where I used 1 for the lifting power of helium). That's more or less a baseball field. And it's just for the naked payload, you still need to account for the envelope itself, the solar panels, the cabin, the engines, the batteries, and the fuel (as, per site, it has a biofuel backup). That probably adds a dozen tonnes at least (the solar panels alone would be 5-10 depending how much of the top's surface is covered). By the end you're probably looking at a men's cricket field, one on the large size.
- jokoon 5y ago
  Yeah 250 tonnes is a lot. Not sure if there is an alternative to helium or hydrogen, like maybe a void container, but it would still be heavy. I guess they will suffer from bad press if they can't prove this can work. Easy to lie to investors but unless they have a prototype, I'm still very skeptical.
khanan 5y ago
"Hi! We built a balloon!" "Okay."
phreeza 5y ago
I don't get why none of these companies try to get ultrarich people to finance their development by selling "air yachts". Basically strap a luxury RV with big windows to the bottom of one of these airships. Imagine the splash you could make at your friends yacht meeting when you float in from above. Watch emperor penguins migrate or elephants in the Okavango delta from the comfort of a couch. What am I missing, why isn't this a thing?
- maxwell86 5y ago
  Because it doesn’t work. You’d need a foot ball field of area, and a 3 story building, to life a small yacht like space. The wind forces on the surface would be extreme, and you’d need a lot of power to even stay somewhere stationary instead of flying away. All of this would add weight, increasing the volume of helium needed, increasing the wind exposed surface area, making the problem worse. You’d need a huge industrial hall to store it safely on the ground, and you can’t tie it with a rope anywhere. The helium required to fill the balloon would make the operating costs of this thing absurd, cause it’s a lot of helium, that leaks all the time and have to be replenished, and helium is super expensive (and necessary for pricy things like cooling superconducting magnets applications, which have infinite budget). Any 3rd year University student with basic knowledge of fluid mechanics, thermodynamics, and mechanic, can draft in a napkin why we already know that this can’t work. I’ve sat in meetings where the VCs contracted me and others to do DD on these types of companies, where every contractor told them that this can’t physically work, and the VCs with too much money take that knowledge and translate it to “very high risk investment”. These companies got 100 million dollars and burnt through them, without nothing to show, but for the VC was more important to not have that money parked somewhere and be able to tell investors that they have “mobility companies” in their portfolio, which I think is borderline misleading / scamming because everyone knew that these companies “concepts” couldn’t physically move a thing, cause that was a physical impossibility with the tech that they wanted to use.
  - phreeza 5y ago
    I don't know, I'm sure you are right that it's not practical as a mass market product. But just coupling together two Zeppelin NTs, they should be able to lift an average RV, so it doesn't seem impossible to me. And something like that should definitely be within the budget of an average billionaire?
s_gourichon 5y ago
Similar project? https://www.flying-whales.com/ https://www.flying-whales.com/ (Not saying if any of those is viable, just mentioning in case it makes the conversation more interesting.)
lordnacho 5y ago
It doesn't look big enough. Basically it's Archimedes principle, same as for stuff that floats: The force produced is the weight of the mass displaced. So a hole in the air would lift up an equivalent mass to what the air in that hole would have weighed. For a ship this is a heck of a lot, since water is a lot denser than air. You can have a huge cruise liner because the hole it makes in the water would weigh 1T/m3, which for the size of such a ship is enough to lift up a massive chunk of metal. But air is nowhere near as dense, so even a cruise ship water-hole sized balloon with magic gas that weighs nothing would only be able to lift ca 1/1000 of the ship. One trick you can do with air is heat it up so that the atoms push the sides out more, making your balloon bigger for the same mass. I'm not sure how to quantify the difference though. I suppose you take the ideal gas law and say it's proportional to the absolute temp? Limited how hot you want to make the thing that's naturally at about 300K. Can't tell how big they intend to make this but it just looks like isn't big enough. A big enough balloon would also give rise to other engineering issues, like what do you do with wind and how to you keep the helium inside? Also if this kind of thing generally worked every moving company would have one. Stick a balloon your sofa, get the kids to take it to your new house.

64 points by aggrrrh 5y ago

This will be a pain in the ass to manage in controlled airspace because it's so much slower than anything else. But I guess it would also use different flight levels, so maybe not a problem at all. I wonder how does the fuel usage compare to a plane, that's the real measure of green-ness.

doikor 5y ago
Just fly it close to the ground and the only controlled airspace is near airports (and some big cities, military stuff, etc). Should not be that hard to stay out of those for the most part if you are transporting stuff like windmill parts to the middle of nowhere.
- lstodd 5y ago
  If you fly low how do you deice the thing while avoiding terrain? Most of the crashes were due to flying into the terrain in adverse weather conditions after all.
  - doikor 5y ago
    Flying low does not mean "scraping trees" but for example Glass G airspace (uncontrolled basically) is everything under 1200' not near airports etc. For a lighter than air craft 1000 feet off the ground is quite a big margin of error actually. And I doubt one would be flying something like this in bad weather anyway. One would just wait for the next weather window. And one could easily take the ship into 4000' or something like that and still have minimal amount of other aircraft around once outside of airports (proper commercial jets fly at 40k feet or so).
    - lstodd 5y ago
      > 1000 feet off the ground is quite a big margin of error actually. Actually, no. It can't maneuver fast enough, it can't gain altitude fast enough. A downdraft or a squall and it's going into a hill or a tree from 1000ft in no time. Only good thing about lighter-that-air is that when they crash, they tend to crash slowly. Otherwise completely useless.
krisoft 5y ago
I think comparing it to a plane is misplaced. They call it a crane. Presumably the load and the craft arrives on a truck and you use it to hoist the load up the last few maybe hundreds of meter max. Do i read that wrong? Edit: yes! I was reading that wrong. To quote the relevant part: “SkyLifters fly from job to job, so they can do work in locations that would be challenging for land cranes.”
- Already__Taken 5y ago
  If you rent a crane though you're also paying for the crew to drive the thing to you. This really has a chance of just auto-piloting over to the job to be then be run by an operator.
  - masklinn 5y ago
    You'll definitely be renting the crew. The skylifter website specifically mentions the one crew. And per my calculations the thing is the size of a cricket or baseball field, there is no way it'll be flying itself.
- masklinn 5y ago
  > Presumably the load and the craft arrives on a truck Nah they're absolutely gigantic and usually semi-rigid (especially if you have solar panels on top). SkyLifter seems very cagey about the purported crane's dimensions (couldn't find anything on the subject), but the Airlander 10 (which I understand only lifts 14t) is 90 x 43 x 26... meters. IIRC the rule of thumb is that you need 1m3 of helium to lift 1kg, to lift just a 250t payload you thus need 250000m3 of helium. According to skylifter's "design" page the lenticular envelope has a height of 1/4th the diameter (3 units wide, 0.75 units deep). For a cylinder that's 108m wide and 27m high, so taking in account the lenticular shape we might be closer to 120m/30m (400ft wide by 100ft high). That's the size of a baseball field, and 14 stories high. And that's only taking the payload in account, not the solar panels, not the cabin, not the engines, ...

Thomaschaaf 5y ago

In germany there was a similar project the "CargoLifter" which sadly never succeeded: https://en.wikipedia.org/wiki/CargoLifter https://en.wikipedia.org/wiki/CargoLifter

Roritharr 5y ago
CargoLifter for me personally marks the beginning of the German Decline in Engineering. The reasons for why it failed are the same reasons why we have such large problems with infrastructure projects and are falling behind in innovative technology. It's a very sad read.
- CoChiefResident 5y ago
  If I remember correctly, Cargolifter failed to have a straightforward loading and unloading method. The airship is designed to lift a certain amount of weight, which has to be replaced as soon as you dismount the cargo. Cargolifter used water which was transported to the destination site via trucks. I only had a quick glance at the SkyLifter website, but I did not find any solution for that problem.
  - capableweb 5y ago
    It seems surprising to me that there is not more information on the website regarding what gas this gas-filled lenticular-shaped aerostat thing is floating with. I understand they are aerostatic and the gas needs to be lighter than air, but that doesn't leave many options that are not helium I guess. And then in order to drop whatever they haul down, they'll need to either let it escape or contain it somewhere else, or spend energy at keeping it down somehow.
- ck45 5y ago
  I have similar feelings about https://en.wikipedia.org/wiki/Transrapid https://en.wikipedia.org/wiki/Transrapid. At some point the whole project became too political and nobody wanted to be responsible to either push the project or pull the plug. Instead a ton of money was basically wasted.

0x_rs 5y ago

Lighter-than-air is still largely untapped territory today, and it's a shame because it should scale in size very well. Without going straight away into more ambitious projects that were fantasized the past century [0], I'd love for a resurgence of it. 0. https://en.m.wikipedia.org/wiki/Cloud_Nine_(sphere) https://en.m.wikipedia.org/wiki/Cloud_Nine_(sphere)

masklinn 5y ago
Tons of companies over the years have taken a shot at it (CargoLifter, Aeros, Walrus HULA, HAV). Turns out, so far, it's all been pretty shit, because outside of super specific niches airships are so slow they need to be much cheaper than aircraft, but the upfront costs to create massive-enough airships to even have a chance makes it a difficult proposition.

londons_explore 5y ago

Doesn't this type of craft normally struggle with any kind of wind? I can imagine that seriously hampers it's profitability when it can't be used 90% of the time because the wind threatens to be more than 10 mph...

wepple 5y ago

Can somebody explain to me how it is able to hover (suggesting it is neutrally buoyant in air) but then attach a load and overcome the weight?

joenathanone 5y ago
It can just swap weight(s).
- Toutouxc 5y ago
  So instead of having to move your 25 ton cargo around, you now have to move your 25 ton ballast to be swapped for the cargo at the drop off point so the SkyLifter doesn't yeet itself into stratosphere. The FAQ and literally everything else about this project is vague, disappointing and a little fishy.
  - joenathanone 5y ago
    Cranes also use counterweights.
    - masklinn 5y ago
      Crane counterweights are a completely different matter. The crane doesn't have to drop the counterweight to take on load (the opposite really, unless it's a superheavy with active counterweighting the entire point is to be more stable once loaded). So the issue with this thing is, any time you move an actual load from A to B, you need to have a weight waiting for you at point B. Or to offgas at which point you won't be able to make a second trip without regassing.
      - joenathanone 5y ago
        If the weights remain on the ground you can use a pulley system to load and unload weight, just put slack in the cable and lighten the load… Could even be automated with the right sensors.

lifeisstillgood 5y ago

I am trying to avoid being negative here but lifting 250 tonnes in remote / difficult areas is a serious challenge. The lift is not so much the problem (although that's a big balloon) - fighting wind sheer will require stupendous amounts of power. Especially as wind is pressing not just at that cargo but at the balloon itself. And anywhere that's remote / inaccessible almost always comes with lots of wind. Hmm, actually lift might be a problem ... So to get 250 000 kg off the ground takes a volume of helium balloon (if the below site is right) of 250,000m3 (it seems to be fairly linear) (this seems intuitive - air "weighs" about 1.2kg /m3 sea level, so a vacuum of 1m3 could lift 1.2kg. ) that is 100mx100mx25m ! that's the inner part of any athletic stadium. That's insane surely? https://www.engineeringtoolbox.com/hot-air-balloon-lifting-force-d_562.html https://www.engineeringtoolbox.com/hot-air-balloon-lifting-f...

CraigJPerry 5y ago
>> that is 100mx100mx25m That’s huge! I wondered how big was the hindenberg, wiki claims 245m long and 41m wide, and 41m tall (excl. cabin). Only 200k litres of gas capacity. 232k tonnes lift.
- ixfo 5y ago
  So it is huge, but well within historic capabilities - and materials science has come a long way since then. I'm quietly hopeful for this.
  - ClumsyPilot 5y ago
    I think the difficulty is not that its a huge airship, its the precision required to use it as a crane.
    - CraigJPerry 5y ago
      That's an area i'd be quietly hopeful in. Assuming propulsion motors are available which are both: a) powerful enough to defend against wind acting against such a huge object b) responsive enough to change their thrust vector (power & direction) such that the associated PID loop can operate within some reasonable set point boundary Then there are already open source hardware and software solutions available for this - i'm not proposing someone slaps a pixhawk 4 on a huge airship and gets a few mates over to help tune the PIDs in Ardupilot - i mean that the know-how is there. Translating that into a product that would be suitable for controlling such an aircraft would be do-able. Certification costs and expensive hardware suitable to run it all on are a different matter. I guess this is a long way to say i don't think it'd be easy or cheap, but i don't think they'd have to make a break through innovation to make it possible.

davidhyde 5y ago

I'm calling bullshit on this. Slick marketing driven website, low resolution photos of actual prototypes, hand-wavy FAQ and no other technical details. They claim speeds of 40 knots but does that mean that can stay stationary in 40 knot winds (the same as traveling at 40 knots) or that it can hitch a ride on high winds? The wind forces on the balloon look they would be far too high for those tiny fans to counteract even with its flying saucer shape. And solar panels to power them? Come on! 250 tonnes is A LOT to lift. Look how big a hot air balloon needs to be to lift a few passengers in a basket. Sure helium has more lifting power but it doesn't create miracles. That means the balloon would have to be absolutely massive. Far bigger than the CGI renders they show on their site. Helium is very expensive and a lot of it will leak out of a balloon like that even if you can reclaim the bulk of it back at the storage site. I'd like to be proven wrong because the idea seems wonderful but the only thing they may be successful at doing is lifting some money from the hands of some gullible investors.

masklinn 5y ago
> 250 tonnes is A LOT to lift. Look how big a hot air balloon needs to be to lift a few passengers in a basket. Sure helium has more lifting power but it doesn't create miracles. That means the balloon would have to be absolutely massive. Agreed, per my calculations it'll need to be around 120m wide, and 30 deep (lifeisstillgood comes up with slightly smaller numbers of 100 x 25, possibly because they used 1.1kg / m3 where I used 1 for the lifting power of helium). That's more or less a baseball field. And it's just for the naked payload, you still need to account for the envelope itself, the solar panels, the cabin, the engines, the batteries, and the fuel (as, per site, it has a biofuel backup). That probably adds a dozen tonnes at least (the solar panels alone would be 5-10 depending how much of the top's surface is covered). By the end you're probably looking at a men's cricket field, one on the large size.
jokoon 5y ago
Yeah 250 tonnes is a lot. Not sure if there is an alternative to helium or hydrogen, like maybe a void container, but it would still be heavy. I guess they will suffer from bad press if they can't prove this can work. Easy to lie to investors but unless they have a prototype, I'm still very skeptical.

khanan 5y ago

"Hi! We built a balloon!" "Okay."

phreeza 5y ago

I don't get why none of these companies try to get ultrarich people to finance their development by selling "air yachts". Basically strap a luxury RV with big windows to the bottom of one of these airships. Imagine the splash you could make at your friends yacht meeting when you float in from above. Watch emperor penguins migrate or elephants in the Okavango delta from the comfort of a couch. What am I missing, why isn't this a thing?

maxwell86 5y ago
Because it doesn’t work. You’d need a foot ball field of area, and a 3 story building, to life a small yacht like space. The wind forces on the surface would be extreme, and you’d need a lot of power to even stay somewhere stationary instead of flying away. All of this would add weight, increasing the volume of helium needed, increasing the wind exposed surface area, making the problem worse. You’d need a huge industrial hall to store it safely on the ground, and you can’t tie it with a rope anywhere. The helium required to fill the balloon would make the operating costs of this thing absurd, cause it’s a lot of helium, that leaks all the time and have to be replenished, and helium is super expensive (and necessary for pricy things like cooling superconducting magnets applications, which have infinite budget). Any 3rd year University student with basic knowledge of fluid mechanics, thermodynamics, and mechanic, can draft in a napkin why we already know that this can’t work. I’ve sat in meetings where the VCs contracted me and others to do DD on these types of companies, where every contractor told them that this can’t physically work, and the VCs with too much money take that knowledge and translate it to “very high risk investment”. These companies got 100 million dollars and burnt through them, without nothing to show, but for the VC was more important to not have that money parked somewhere and be able to tell investors that they have “mobility companies” in their portfolio, which I think is borderline misleading / scamming because everyone knew that these companies “concepts” couldn’t physically move a thing, cause that was a physical impossibility with the tech that they wanted to use.
- phreeza 5y ago
  I don't know, I'm sure you are right that it's not practical as a mass market product. But just coupling together two Zeppelin NTs, they should be able to lift an average RV, so it doesn't seem impossible to me. And something like that should definitely be within the budget of an average billionaire?

s_gourichon 5y ago

Similar project? https://www.flying-whales.com/ https://www.flying-whales.com/ (Not saying if any of those is viable, just mentioning in case it makes the conversation more interesting.)

lordnacho 5y ago

It doesn't look big enough. Basically it's Archimedes principle, same as for stuff that floats: The force produced is the weight of the mass displaced. So a hole in the air would lift up an equivalent mass to what the air in that hole would have weighed. For a ship this is a heck of a lot, since water is a lot denser than air. You can have a huge cruise liner because the hole it makes in the water would weigh 1T/m3, which for the size of such a ship is enough to lift up a massive chunk of metal. But air is nowhere near as dense, so even a cruise ship water-hole sized balloon with magic gas that weighs nothing would only be able to lift ca 1/1000 of the ship. One trick you can do with air is heat it up so that the atoms push the sides out more, making your balloon bigger for the same mass. I'm not sure how to quantify the difference though. I suppose you take the ideal gas law and say it's proportional to the absolute temp? Limited how hot you want to make the thing that's naturally at about 300K. Can't tell how big they intend to make this but it just looks like isn't big enough. A big enough balloon would also give rise to other engineering issues, like what do you do with wind and how to you keep the helium inside? Also if this kind of thing generally worked every moving company would have one. Stick a balloon your sofa, get the kids to take it to your new house.