That technology still has a very long way to go before it's proven itself safe and reliable. (If it ever does). Don't get caught up in the hype some companies create. I'm describing a system that could be implemented now with known pneumatic tube technology. (Yes there are companies that specialize in that).

Yet you're completely ignoring the time and cost to create such a ridiculous infrastructure. Automated cars will be ready in a fraction of the time at a fraction of the cost while leveraging the existing infrastructure.

It's not the reason you're thinking. We'd be de-railing the thread if we went into why ISPs didn't run fiber to everyone's house for the good of everyone. It's not because of density.
[/quote]

It is ignorant to believe that our size and population density have nothing to do with our infrastructure problems. The reason we do not have a complete fiber network is because it doesn't make financial sense to provide fast a connection to 80% of this country. That is also primary reason why your tube idea is ridiculous. Exactly why when this idea came around over 100 years ago, it was dropped as being unfeasible. Clearly you're not up for any criticisms of your idea, and surely the only reason this genius plan hasn't been implemented is that no one has thought of applying modern materials to century old failed technology. ApochPiQ had the right idea as you're not interested discourse.

It is ignorant to believe that our size and population density have nothing to do with our infrastructure problems. The reason we do not have a complete fiber network is because it doesn't make financial sense to provide fast a connection to 80% of this country. That is also primary reason why your tube idea is ridiculous. Exactly why when this idea came around over 100 years ago, it was dropped as being unfeasible. Clearly you're not up for any criticisms of your idea, and surely the only reason this genius plan hasn't been implemented is that no one has thought of applying modern materials to century old failed technology. ApochPiQ had the right idea as you're not interested discourse.

Look at it this way. If the system was fully implemented 100 years ago it would now be a common thing. People wouldn't question its design because they'd just say "everyone in the world gets mail every week. Can you imagine someone driving around every week and putting mail in a box? Mail is just delivered to my house by an automated system."

There is the extreme of comparing it, not to the fiber idea, but to the phone system. We take that for granted since it allow instant communication to anyone in the world. If we didn't have it now people would assume the infrastructure cost would be too high. However, it had one thing that existed and it was demand. (Or at least there was demand when people knew they could have it). Obviously nowadays we already have a system that works so trying to push in a better (being the subjective word in this debate) system is extremely hard since the demand is no longer there for a system. It's the problem of choosing a inferior system when the technology wasn't up to meet the demand. Now it is, but the traditional system is so rooted into society that the better system can't take over (fiber for instance when inferior choices still exist). And because of that it never will fully. So even in 1000 years from now when we still need to deliver packages we'll always have UPS and FedEx.

Also I'm fully interested in discourse and I agree with your sarcastic viewpoint regarding not applying modern materials; however, I wouldn't view it as failed technology. It merely lost popularity to other systems, but for all intents and purposes the technology was a success. That's the difference I think that's separating this discussion. If it didn't work there wouldn't be companies that create and install such systems into buildings even today.

The whole idea of this thread was to make people see that the technology is there and worked, but just needs the popularity to replace the traditional way.

There is the extreme of comparing it, not to the fiber idea, but to the phone system. We take that for granted since it allow instant communication to anyone in the world. If we didn't have it now people would assume the infrastructure cost would be too high. However, it had one thing that existed and it was demand. (Or at least there was demand when people knew they could have it).

The phone system is a bad comparison. It is relatively cheap and simple compared to the system you're talking about.

Obviously nowadays we already have a system that works so trying to push in a better (being the subjective word in this debate) system is extremely hard since the demand is no longer there for a system. It's the problem of choosing a inferior system when the technology wasn't up to meet the demand. Now it Tis, but the traditional system is so rooted into society that the better system can't take over (fiber for instance when inferior choices still exist).[/quote]

Again, you're asserting that it is somehow better, but you have no evidence to support that other than at a micro scale. I still don't think you grasp the magnitude or complexity of the system you're proposing.

Also I'm fully interested in discourse and I agree with your sarcastic viewpoint regarding not applying modern materials; however, I wouldn't view it as failed technology. It merely lost popularity to other systems, but for all intents and purposes the technology was a success. That's the difference I think that's separating this discussion. If it didn't work there wouldn't be companies that create and install such systems into buildings even today.[/quote]

It is a failed technology for the scale you're talking about and saying that it will work on a national scale because it works in a building is quite frankly stupid. By that metric, all we have to do to have national wifi is to install linksys repeaters every 50' across the whole country! After all, it works in an office building! The most comparable project is probably the Trans-Alaska oil pipeline. That covers 800 miles and cost approximately $30 billion in today's dollars. A good guess at what it would take to cover the major cities would be to use the US interstate system as a guideline. That's close to 47,000 miles. That means to just build the pipes to connect major cities in the USA you're looking at somewhere around 1.7 trillion dollars. And that would get you something like this.

http://upload.wikime...Interstates.svg

Expand that from major cities to smaller cities and from there to residences and you start to get some grasp of the size and complexity of the system you're proposing. This is all without the cost of your giant magical routers which direct the traffic of packages travelling through the system and without all of the monitoring or maintenance that would go into maintaining this monstrosity.

Nevermind the fact that vandalism and theft would become a much larger problem. Back your truck up to the pipe, cut a hole in it and packages start to fall into the back of your truck. Since these pipes have to span hundreds of miles of unoccupied land, there is little to no chance of preventing this.

No matter how you slice it, this wouldn't work over long distances. Existing pneumatic systems succeed by limiting the distance and size/mass of objects transported. As soon as you try to remove either barrier, the difficulty of solving the problem scales nonlinearly. You can't just throw N times as much horsepower at it, it's probably closer to N^2.

Exactly. ApochPIQ came up with a fine analogy already, with the tubes.

Imagine pushing a shelf with the weight of your body, on a slippery floor. Given enough force, that would work, and the shelf will slowly accelerate to a maximum velocity limited by it's aerodynamic properties, your weight/force applied, and the friction with the floor.

Now imagine pushing three shelves. you wouldn't just push 3 times their masses. You would push against 3 combined response vectors (and all their components such as friction and following shelves), thus it would take more than 3 of you.

If you have airtightness (no pressure loss between capsule and compressor), and no friction with anything at all, you could gear the pressure and have more compressors to gradually push the capsule in the desired direction. And that's a nice thought.
However, you would still have mentioned limitations (airtight or not), and as the tubes will still contain air, there'll likely be several tonnes extra to push.

[quote name='ApochPiQ' timestamp='1315454902' post='4858915']
No matter how you slice it, this wouldn't work over long distances.

We'll need to agree to disagree then. I see no physical limitations in the system that would prohibit it from working over the required distances.
[/quote]
That is exactly the essentials of the physical limitation.

But you're right about this one:
[font=arial, verdana, tahoma, sans-serif][size=2]

Look at it this way. If the system was fully implemented 100 years ago it would now be a common thing. People wouldn't question its design because they'd just say "everyone in the world gets mail every week. Can you imagine someone driving around every week and putting mail in a box? Mail is just delivered to my house by an automated system."

[/font][font=arial, verdana, tahoma, sans-serif][size=2]Although the fully implemented system would probably be the result of compromises and dealing with the beforementioned issues. We want to implement a system, we do it. (humans)[/font]

You really seem to be forgetting just how much energy would be required.

For an air tube system, where the container length is a minor fraction of the overall tube length, your primary friction becomes not the packets, but the air flowing through the pipe. This means that pushing 1 packet through is going to take similar energy to pushing 100 packets through.

So, what does this mean? Either we have to send a LOT of packets so that the tube is always near capacity all the time, or the tubes only run for a set period of time, and collect packets before sending them off.


Kind of like how the existing systems work, only they use trucks running on roads instead of tubes, and sorting centers instead of 'routers'.


What are the big causes of delays? Mostly package volume. Companies have X amount of money for things like trucks and aircraft, and a truck sitting in a yard isn't earning a company money. So they look at the past history of packages from an area, and assign a suitable number of transport vehicles to it. If a depot has less packages to send than would be required to make a profit, then they will usually sit and wait for more that can be put on the same truck/plane/ship. If there are too many packages, then the highest priority ones go first. Meaning if there is space for X number of packages on the vehicle, and X+1 come in that day, then one gets left behind. If your package happened to be a low priority shipping fee and everyone else was high priority, then guess who gets left on the loading dock? And if X high priority packages come in the next day? And the day after? Eventually they would bump a high priority to ship a back logged low priority, but it rarely happens.

Nevermind the fact that vandalism and theft would become a much larger problem. Back your truck up to the pipe, cut a hole in it and packages start to fall into the back of your truck. Since these pipes have to span hundreds of miles of unoccupied land, there is little to no chance of preventing this.

Do I have to remind you how most people give their mail the USPS? Via little boxes in the middle of nowhere or they put the package into their mailbox? What your suggesting is a magnitude more difficult to do. Preventing is would be fairly easy. The system expects packages at routers. If they don't see a package that was sent the system immediately notices the problem.

Cutting a pipe and trying to grab packages at they're traveling and doing that for an extended period of time is as lucrative as running your car into a blue box and grabbing all the letters or driving down the street and taking people's mail out of their mailboxes.

[quote name='ApochPiQ' timestamp='1315454902' post='4858915']
No matter how you slice it, this wouldn't work over long distances. Existing pneumatic systems succeed by limiting the distance and size/mass of objects transported. As soon as you try to remove either barrier, the difficulty of solving the problem scales nonlinearly. You can't just throw N times as much horsepower at it, it's probably closer to N^2.

Exactly. ApochPIQ came up with a fine analogy already, with the tubes.


Imagine pushing a shelf with the weight of your body, on a slippery floor. Given enough force, that would work, and the shelf will slowly accelerate to a maximum velocity limited by it's aerodynamic properties, your weight/force applied, and the friction with the floor.

Now imagine pushing three shelves. you wouldn't just push 3 times their masses. You would push against 3 combined response vectors (and all their components such as friction and following shelves), thus it would take more than 3 of you.

If you have airtightness (no pressure loss between capsule and compressor), and no friction with anything at all, you could gear the pressure and have more compressors to gradually push the capsule in the desired direction. And that's a nice thought.
However, you would still have mentioned limitations (airtight or not), and as the tubes will still contain air, there'll likely be several tonnes extra to push.
[/quote]
They've pushed trains just by using air from a blower. They had wheels, but the idea still holds. You're overestimating the amount of force required and the effect of sliding friction on the system. (I'm still assuming no ball bearings and just a plastic vs PVC friction). I can't seem to find the kinetic friction for plastic on PVC or alluminum on PVC, but I believe from other values it's less than 0.5 which is barely anything on a system with the pressure we're talking about.

Say the smallest container is 30 cm. That gives it an area of PI * (0.15 m)^2 = 0.071 m^2. Now pretend with have 1 atm aka 101325 Pa on one side and 30 psi aka 206843 Pa on the other. Using F = P * A we can calculate the net force of (206843 Pa - 101325 Pa) * 0.071 m^2 = 7490 N... wait that doesn't seem right. Now we assume the object weighs 20 lbs or 9 kg giving it a kinetic friction (if we assume 0.5 as a worst case coefficient) of (mu * m * a), 0.5 * 9 kg * 9.8 m/s^2 = 44 N. So 7490 N - 44 N = 7446 N for a total acceleration of 7446 N / 9 kg = 827.3 m/s^2.... that's not right. I mean it's not a perfect seal so obviously the force would be cut in half but even then? I've never taken a fluid dynamics class so I have no idea how to calculate the force on an object caused by pressure differences. Anyone know those equations?

Also remember I'm assuming a continuous circular column (like in the picture) of moving air caused by blowers or electric ducted fans so I was assuming a constant pressure difference. hmm, maybe I'm overestimating the pressure build up behind the object. Obvious as it begins to move the pressure doesn't stay constant so its acceleration slows as it tries to match the flow of the air column. Not sure how to calculate that. I imagine it involves an integral. Basically what I was trying to do was to find the speed of the air column that would be sufficient to move an object of that size and mass including the sliding friction.

I can't say with certainty, but I have a suspicion that the energy required isn't as costly as it might seem.

You really seem to be forgetting just how much energy would be required.

For an air tube system, where the container length is a minor fraction of the overall tube length, your primary friction becomes not the packets, but the air flowing through the pipe. This means that pushing 1 packet through is going to take similar energy to pushing 100 packets through.

Yeah that's kind of assumed. Moving the air column is how the whole system operates and will be where all the energy is being used. Nagling is optional really and depends on the cost of turning the system on for a link. Obviously if the electricity cost is high (like a few cents then that changes things. How much would it cost to run an electric air ducted fan system to push a package by itself across the country? 5 dollars? Those are the kinds of costs that would need to be calculated by actual engineers.

They've pushed trains just by using air from a blower. They had wheels, but the idea still holds. You're overestimating the amount of force required and the effect of sliding friction on the system. (I'm still assuming no ball bearings and just a plastic vs PVC friction). I can't seem to find the kinetic friction for plastic on PVC or alluminum on PVC, but I believe from other values it's less than 0.5 which is barely anything on a system with the pressure we're talking about.

they pushed it a couple blocks. Not across the country.

Say the smallest container is 30 cm. That gives it an area of PI * (0.15 m)^2 = 0.071 m^2. Now pretend with have 1 atm aka 101325 Pa on one side and 30 psi aka 206843 Pa on the other. Using F = P * A we can calculate the net force of (206843 Pa - 101325 Pa) * 0.071 m^2 = 7490 N... wait that doesn't seem right. Now we assume the object weighs 20 lbs or 9 kg giving it a kinetic friction (if we assume 0.5 as a worst case coefficient) of (mu * m * a), 0.5 * 9 kg * 9.8 m/s^2 = 44 N. So 7490 N - 44 N = 7446 N for a total acceleration of 7446 N / 9 kg = 827.3 m/s^2.... that's not right. I mean it's not a perfect seal so obviously the force would be cut in half but even then? I've never taken a fluid dynamics class so I have no idea how to calculate the force on an object caused by pressure differences. Anyone know those equations?[/quote]
so using your smallest container .071m^2.

total distance of a single tube from new york to california is 2905 miles =4675km.
Total volume of your tube is 332,000 m^3.
The total weight of the air in that tube, which you have to move every time you send a package is 398310 kg plus the weight of the package.

That is not taking into account that you have to deal with balancing all the pressures across an entire web. Not just a single tube.

Do I have to remind you how most people give their mail the USPS? Via little boxes in the middle of nowhere or they put the package into their mailbox? What your suggesting is a magnitude more difficult to do.

You mean someone's mailbox in front of their house? The chance of getting caught is much higher as you could cut the pipe 20 miles from any living person.

Preventing is would be fairly easy. The system expects packages at routers. If they don't see a package that was sent the system immediately notices the problem.[/quote]

That is not prevention, it is detection. How exactly would you prevent this?

Cutting a pipe and trying to grab packages at they're traveling and doing that for an extended period of time is as lucrative as running your car into a blue box and grabbing all the letters or driving down the street and taking people's mail out of their mailboxes.[/quote]

This system is for packages, not letters right? It's going to be more like ripping off the contents of an entire UPS truck, I am sure there are plenty of valuables in there.

They've pushed trains just by using air from a blower. They had wheels, but the idea still holds. You're overestimating the amount of force required and the effect of sliding friction on the system. (I'm still assuming no ball bearings and just a plastic vs PVC friction). I can't seem to find the kinetic friction for plastic on PVC or alluminum on PVC, but I believe from other values it's less than 0.5 which is barely anything on a system with the pressure we're talking about.[/quote]

No, you're dramatically underestimating the friction. You've got plastic sliding on plastic for miles, you're bound to get high temperatures and melting plastic.

so using your smallest container .071m^2.

total distance of a single tube from new york to california is 2905 miles =4675km.
Total volume of your tube is 332,000 m^3.
The total weight of the air in that tube, which you have to move every time you send a package is 398310 kg plus the weight of the package.

That is not taking into account that you have to deal with balancing all the pressures across an entire web. Not just a single tube.

Probably a little bit more since it's an imperfect seal. When you do the math doesn't it seem a lot more realistic? I mean look at even the most basic blower's that the industry uses are 50K to 100K cfm (cubic feet per minute).

Being optimistic it would only need to run such a fan for 2 hours, but that would be a lot of pressure. You'd probably end up with smaller more efficient blowers built into the links.

[quote name='Sirisian' timestamp='1315602259' post='4859748']
They've pushed trains just by using air from a blower. They had wheels, but the idea still holds. You're overestimating the amount of force required and the effect of sliding friction on the system. (I'm still assuming no ball bearings and just a plastic vs PVC friction). I can't seem to find the kinetic friction for plastic on PVC or alluminum on PVC, but I believe from other values it's less than 0.5 which is barely anything on a system with the pressure we're talking about.

No, you're dramatically underestimating the friction. You've got plastic sliding on plastic for miles, you're bound to get high temperatures and melting plastic.
[/quote]
That's the wonderful thing about PVC. Most of them don't melt until well over 300 F (150 C). It would need to be something tested though by an engineer to see if it's a problem. The amount of air moving through the system provides a natural cooling mechanism for the tubes.