How to build a flying city

[searchingfortruth]

What we could achieve in the here and now if money was not a factor.

You're confusing me with what you want. In the 1st post, you give the impression you want to talk about realistic and practical things. Things we can build right now if we had enough money and motivation.

 

But in another post (#19), you talk about future tech that we might develop some day.

 

The difference between "practical, right now", and "future tech, some day", is that right now we have limited energy, and some day, we might have almost infinite energy. And that makes a huge difference when you talk about getting stuff into orbit!

 

If you want to get a lot of stuff into orbit, you need a LOT of energy. Low Earch Orbit is about 7.8 km/s, so the kinetic energy for 1 kg is about 30 MJ/kg (excluding all practical issues - in current rocket technology you need to spend a lot more energy).

 

So, what's the topic of the thread? Practical orbital city with real technology (but unlimited financial means)? Or future technology, bound only by the laws of physics (in other words: sci-fi)?

[Realitycheck]

Antigravity is really the only realistic method to achieve these goals, as is the case with all of the most popular sci-fi flicks. It's just a matter of bending reality to our will. I'm sure we'll think of something.

[dimreepr]

I can think of only one way to even come close to achieving this, in the near future, and that is to go with Arthur C. Clark and build the city in space using a space elevator. The only reasons to build it is either overpopulation or natural disaster.

[CaptainPanic]

Antigravity is really the only realistic method [...]

That just sounds funny

 

I understand what you meant to say though, and this post is not very helpful for the thread. Still, it made me chuckle.

[Spyman]

The topic is supposed to be "How To Make A Flying City" and nobody is discussing this. So here are some questions. What propulsion system would we use? What type of design? How would we make it? What would we use to make it? How would we power it?

What is a "Flying City"? If we are talking about a Space Colony like this:

 

A space habitat (also called an orbital colony, or a space colony, city, or settlement) is a space station intended as a permanent settlement rather than as a simple waystation or other specialized facility. No space habitats have yet been constructed, but many design proposals have been made with varying degrees of realism by both engineers and science fiction authors.

http://en.wikipedia.org/wiki/Space_habitat

 

Then IMHO the best we can think of today is some variant of a Bernal sphere:

 

A Bernal sphere is a type of space habitat intended as a long-term home for permanent residents, first proposed in 1929 by John Desmond Bernal.

Bernal's original proposal described a hollow spherical shell 1.6 km (0.99 mi) in diameter, with a target population of 20,000 to 30,000 people. The Bernal sphere would be filled with air.

http://en.wikipedia.org/wiki/Bernal_sphere

 

THE DESIGN AND VISUALIZATION OF A SPACE BIOSPHERE

Lewis One is a qualitative space biosphere design. It is intended to house 10,000 residents in a cylinder large enough for a 1g rotating habitat module and construction facilities to reproduce the module. The shielding, exterior, and construction bays are non-rotating. Lewis One is compared to the Bernal Sphere space colony designed in the 1970s. Lewis One is visualized using state of the art computer graphics hardware and software to roduce a three dimensional, animated, lighted, shaded, texture mapped surface model.

http://www.nas.nasa.gov/assets/pdf/techreports/1991/rnr-91-018.pdf

Edited January 27, 2012 by Spyman

[lahan]

I agree to Tres Juicy. Because how can we control a flying city?and It will be disturbence to the flight services.

[InigoMontoya]

What we could achieve in the here and now if money was not a factor.

 

Money is not a factor... That right there could have unintended consequences.

 

How much havoc are you willing to cause the rest of the world?

 

By that I mean things like.... Global shortages of food and goods because you're using enormous amounts of petroleum to launch stuff (thereby not leaving enough for people to transport food around).

 

How many lives are you willing to destroy for your city?

 

So while money may not be a factor... What else may be?

Edited January 27, 2012 by InigoMontoya

[searchingfortruth]

Theoretically, if money and resources were unlimited.

Money is not a factor... That right there could have unintended consequences.

 

How much havoc are you willing to cause the rest of the world?

 

By that I mean things like.... Global shortages of food and goods because you're using enormous amounts of petroleum to launch stuff (thereby not leaving enough for people to transport food around).

 

How many lives are you willing to destroy for your city?

 

So while money may not be a factor... What else may be?

[InigoMontoya]

Well, with unlimited money and resources.... Sure, you could put the world's population in orbit in just a few years. Alas, "unlimited money and resources" is every bit as realistic as colonizing the Sun.

Edited January 28, 2012 by InigoMontoya

[Xittenn]

as [math] t \to [/math] very large positive number

 

1 - Synthetic Ecosystems

 

2 - planet cored

 

3 - planet dismantled in structured layers

 

4 - synthetic biosphere created; planets surface area increased x fold

 

I believe this will be a consequence of economics, and my first assertion. I don't however, believe there will ever be a popular demand for flying cities, no matter the availability of such technology; again, I believe this to be a question of economics.

[finster]

To live in a flying city would be truly amazing, but how would we make it fly, power it, and control it?

 

This is probably easier for us to do than you think, though it would be no way near the size of a modern city.

 

We're talking small fry populations at first but all we need to do is strap some solar (and fuel fired, just in case) balloons to a large platform. And on the platform, we add everything we will need to survive in the clouds: small farms for food, solar panels for electricity, water catchment system for water harvesting, some light structures for lodging and protection from the elements. What else? A radio to keep an eye on the weather so you're not caught in dangerous skies. Maybe the ability to lower small motor boats while close to the ocean surface so they can stock up on emergency supplies at the nearest shore town, if required.

 

This is totally doable with current technology, especially on a small one person scale. Think of it: First you could fly it above low clouds just in case they are blocking the sunlight to your solar balloons and panels. You could also fly away from approaching bad weather. No property taxes because, well, you'll have no property. You could even fly out to international waters, renounce your citizenship and proclaim yourself and free state and no one could stop you.

 

 

 

[CaptainPanic]

This is probably easier for us to do than you think, though it would be no way near the size of a modern city.

 

We're talking small fry populations at first but all we need to do is strap some solar (and fuel fired, just in case) balloons to a large platform. And on the platform, we add everything we will need to survive in the clouds: small farms for food, solar panels for electricity, water catchment system for water harvesting, some light structures for lodging and protection from the elements. What else? A radio to keep an eye on the weather so you're not caught in dangerous skies. Maybe the ability to lower small motor boats while close to the ocean surface so they can stock up on emergency supplies at the nearest shore town, if required.

 

This is totally doable with current technology, especially on a small one person scale. Think of it: First you could fly it above low clouds just in case they are blocking the sunlight to your solar balloons and panels. You could also fly away from approaching bad weather. No property taxes because, well, you'll have no property. You could even fly out to international waters, renounce your citizenship and proclaim yourself and free state and no one could stop you.

I have a few issues with this:

 

1. If you have balloons, you will get very little sunlight for your small farms. Your own balloon will block the light.

2. You cannot avoid the weather. You just go where the wind takes you. All you can do is change your altitude.

3. The airspace above a country is legally owned by that country and they can legally deny you access.

4. You need seriously huge balloons to do this. The cost of the construction, as well as the helium would be astronomical.

[finster]

I have a few issues with this:

 

1. If you have balloons, you will get very little sunlight for your small farms. Your own balloon will block the light.

2. You cannot avoid the weather. You just go where the wind takes you. All you can do is change your altitude.

3. The airspace above a country is legally owned by that country and they can legally deny you access.

4. You need seriously huge balloons to do this. The cost of the construction, as well as the helium would be astronomical.

 

 

 

 

 

On Point 1: The farms would obviously have to be positioned to get optimal sunlight, possibly even on a platform above or well below the balloons. If the farm platforms are hanging well below the supporting balloons, sunlight should be able to hit them.

 

On Point 2: Even though I used the word "balloons" I was referring to blimp shaped balloons which, as you know, are maneuverable because of propellers.

 

On Point 3: Of course, a nation will assert their airspace boundaries but that would only be a problem if you renounced your citizenship to your country. I'm assuming if you did, you would have resources already set up for yourself outside that country.

 

On Point 4: The size of the balloons would be, of course, dependent on the weight and size of your platform. As for helium, my suggestion was to use solar balloons with hot air emergency balloon supplements. With solar balloons you would have to be wary of cloud cover and make sure you were either above the clouds or out of cloud cover.

 

 

 

 

[InigoMontoya]

This is totally doable with current technology, especially on a small one person scale.

No, it isn't.

[finster]

No, it isn't.

 

Since a modified blimp is basically what we are talking about, I beg to differ.

 

Here is one small scale design.

 

http://www.yankodesign.com/2012/03/29/flying-home-of-tomorro/

[InigoMontoya]

Since a modified blimp is basically what we are talking about, I beg to differ.

 

Here is one small scale design.

 

http://www.yankodesign.com/2012/03/29/flying-home-of-tomorro/

 

When you start talking about farms and the like, the amount of materials (read: water, etc.) required to keep one person alive quickly become too much to keep in the air. At that point, you're no longer talking about a "city" in the air or anything and are instead just talking about a glorified RV. That's a very different proposition.

 

Could you make a home out of a blimp? Sure.

 

Could you make anything that resembles being self sufficient (ie, a city)? I maintain that the answer is "no."

 

I further note that your linked to design is vaporware.

[finster]

When you start talking about farms and the like, the amount of materials (read: water, etc.) required to keep one person alive quickly become too much to keep in the air. At that point, you're no longer talking about a "city" in the air or anything and are instead just talking about a glorified RV. That's a very different proposition.

 

Could you make a home out of a blimp? Sure.

 

Could you make anything that resembles being self sufficient (ie, a city)? I maintain that the answer is "no."

 

I further note that your linked to design is vaporware.

 

no city on land is entirely self-sufficient either. total self sufficiency is not a requirement for this to work, afaic.

 

at the most basic level, cities are a collection of homes (or at least evolve out of a collection of homes.) if one home can be made to suspend itself in the sky, you can have many more. eventually, they can be connected to form a small "town". you can take it from there...

 

 

 

Edited September 30, 2012 by finster

[InigoMontoya]

if one home can be made to suspend itself in the sky, you can have many more. eventually, they can be connected to form a small "town".

And THAT is where I disagree.

 

I don't believe that a blimp would scale well. You're talking about a very large, very fragile object. If a blimp is reasonably small, it can be simply taken indoors to weather storms. But if it's sufficiently large, where are you going to park it? And don't say that you can simply avoid storms by moving around. That works for a while but sooner or later you'll find yourself in a situation where you simply can't run and you MUST weather some level of a storm. I simply don't believe a blimp large enough to classify as a small "town" could also withstand anything that resembled bad weather. The square/cube law just bites such systems in the arse.

[finster]

And THAT is where I disagree.

 

I don't believe that a blimp would scale well. You're talking about a very large, very fragile object. If a blimp is reasonably small, it can be simply taken indoors to weather storms. But if it's sufficiently large, where are you going to park it? And don't say that you can simply avoid storms by moving around. That works for a while but sooner or later you'll find yourself in a situation where you simply can't run and you MUST weather some level of a storm. I simply don't believe a blimp large enough to classify as a small "town" could also withstand anything that resembled bad weather. The square/cube law just bites such systems in the arse.

From an airship website:

 

"Reality - Small non-rigid airships may have long-range difficulty in severe weather, but there are several recorded instances of large airships encountering severe squalls and passing through intact. The success of German zeppelins in severe weather came down to both great piloting skill as well as structural engineering. British and American rigid airships succumbed to bad weather in large part due to avoidable piloting errors and structural flaws.Today there are two major developments that further diminish bad weather as a problem for airships. Advances in weather tracking technology and the development of more powerful vectoring propulsion systems combine to help airships avoid inclement weather altogether or be able to ride out the storm. Advances in flight instrumentation, structural design techniques and material strengths could also serve to further enhance the durability of any modern rigid airships.

 

Bad weather poses the greatest risk not to airships in flight, but to airships taking off and landing. Take off and landing procedures could be further developed with technology. In the event of poor weather conditions airships may delay a take-off or landing just as airplanes do."

 

 

 

 

More airship myths debunked at link: http://airshiphangar.com/misconceptions.html

 

 

 

[t-rav]

I believe it can be done. It wouldn't be a city like we know. Each building would have its own power source. The power would come from wind turbines and solar energy, which would power a cycle fan below the structure. The fan would draw in air, and force the air out through vents facing down, thus propelling the building up, and eventually to a point it which it would float. and below each building would be a parachute-type fabric to give the propelled air something to bounce off of, creating a current for the floating action. These tarps would be deployed once the building is high enough. And if there is not enough air strength to launch the building, you could use a blimp. The blimp could possibly stay attatched to lessen the amount of power the fans would need. Each building would be surrounded by a "yard." The yard could have grass and plants. The walk ways would be made of a very light metal, to reduce weight. Every building would be its own structure. For streets, they too would be their own structure, not connected to buildings permanetly, in case of emergencies. The streets would simply float next to the buildings so citizens could easily walk back and forth. There would, of corse, be no vehicles due to their weight. In case of a building falling, a parachute would be deployed. This project would be very expensive, and some major research would have to done for the fans, too. I believe my theory is a stepping stone for inventors

 

[arc]

And who are the lucky ones that get to have your daily byproducts rain down on them, you know, the liquids and solid wastes that would normally be piped to a wastewater treatment facility.

 

http://www.eolss.net/eolsssamplechapters/c06/e6-13-04-05/E6-13-04-05-TXT-05.aspx

 

"On average the overall wastewater generation rate is approximately 265 liters per capita and per day in the U.S."

[Endy0816]

Ideally though you would recycle most of it. Anything that saves on pumping or bringing up resources from the ground would be a boon.

 

Fertilizer, gray water reuse, purification back into potable water. Possibly even offload it via hoses to the ground depending on what is available. Worst case move the city over an ocean and you can straight dump it. I imagine they might still use a hose to keep it from being an eyesore.

[Marshalscienceguy]

I dont think a flying city wouldnt make much sense. Now a levitating city might. If the city is constantly flying you have to steer it and figure out where to land. I think it would make a lot more sense to just have it levitate if you just want it up in the air. You can make things levitate using magnets but to do it with something of such a large scale would prove to be difficult. Though maybe you could get the base to be a large metal plate and trying to leverage the weight evenly around the city. They did this in sky high but actually doing this is hard to imagine. Than all around the base of it you can put magnets on both the top and the bottom.

Edited April 4, 2014 by Marshalscienceguy

[CaptainPanic]

If you want to levitate your city some 5 centimeters above the ground, I think the magnets are quite feasible.

If you want kilometers, then I think that you run into some practical problems.

 

I recommend concrete or steel pillars. While it is not exactly flying, it is far more practical.

The only realistic alternative is to get your city into orbit.

 

Anyway, apart from the coolness factor (the 'science fiction factor'), I still fail to see the point.

[JebMFBradwell]

I'm building a flying city currently. I was wondering if anyone was interested in helping crowed source the project? I've found an economical way to accomplish it. I'm looking to free those who want to be free and not governed by any. Let me know if you are interested. email removed

 

I am not looking for people who are weak. You must have courage and know how to let go of your ego and what you know currently. Those realities will get in the way of this project. You must be able to imagine and create.

 

Please do not bother me with any weak mind inquiries.

 

For freedom,

 

Jeb