Elon Musk's Hyperloop concept

[sferrin]

Must be nice to be some middle aged guy, sitting in an ivory tower full of knowledge and shit on some engineering students that surely must be idiots. : Does this kind of attitude come with age or were you always like this? Same thing about murmuring how "everything was better before" while not attempting anything new because reasons. And god forbid anyone trying!

This reads like, "old SOBs don't know anything, WHAAA!" :

 

[Orionblamblam]

Must be nice to be some middle aged guy, sitting in an ivory tower full of knowledge and shit on some engineering students that surely must be idiots. :

My problem with hyperloop isn't the engineering students; it's with the whole *concept.* It has some substantial flaws. You ignore those flaws at your (and your investors) peril.

There are some ideas that are challenging, like low-cost recoverable (and hopefully reusable) space launch systems. The math on those works. But other ideas, the math *doesn't* work. What make a "good idea" isn't just that it's a "cool idea," but an idea that can work, and would work better than the known alternatives. Hyperloop? Naw, not so much. *Can* it work? Sure. Doesn't violate the laws of physics. But there are *massive* engineering and logistical problems that must be worked out, and working them out requires more than just imagination.

And, yes, sometimes college students *can* be idiots. Take, for example, everyone who worked on the "WaterSeer" or the solar roadways or the self-filling water bottle or the plastic roadway without doing the math first, or who did the math and chose to ignore it.

https://youtu.be/LVsqIjAeeXw

 

[sferrin]

Yeah, was going to put that CF up as an example. Talk about using wishes and rainbows instead of actual science. ;D

 

[flanker]

>Some new engineering ideas are clearly BS (like solar roadways)
>That must mean every new engineering idea is clearly BS

Well, i guess that pretty much settles it then. I cant be bothered to watch your example tbh, but i will take your word for it. Doesnt change the fact it is not really relevant to the hyperloop.

But i wont bother to change your mind on it. It is one thing to be skeptical and question the engineering (which is completely fine of course), it is another thing to outright dismiss something based on an extremely hyperbolic, obviously clickbaity 13 min youtube video.

 

[Hobbes]

Meh. Stepping through the video at random, the first (fairly basic) point he makes is incorrect.

His first point was that there had been "wall to wall" coverage of the hyperloop competition that week. That may be a bit hyperbolic, but hardly "incorrect" as such.

I should have been clearer. At about 4 min. into the video, it's mentioned it will take about half an hour to pump out the air from the test tube (500 m long?). The narrator then goes on to splutter about how 30 minutes is long enough to make the entire system unusable, glossing over a few things like airlocks (of course you're not going to pressurize and depressurize your main tube when it's in production), and the idea that a test installation may take longer to evacuate than a production installation.

 

[flanker]

He glossed over everything and went into a full on hyperbole. There WAS a plan to have an airlock design. But they simply didnt have time. You know, because SpaceX engineers tend to be busy with other easy stuff day-to-day, they clearly dont have brainpower enough for an airlock design unlike certain arm chair experts.

 

[Orionblamblam]

I should have been clearer. At about 4 min. into the video, it's mentioned it will take about half an hour to pump out the air from the test tube (500 m long?). The narrator then goes on to splutter about how 30 minutes is long enough to make the entire system unusable, glossing over a few things like airlocks

Uh-huh. And how big is the airlock? Here's a hint: it has to be substantially longer than an individual car. The airlock will almost certainly have to have a vacuum-sealed sizable door on the *side* the size of a car... not a relatively simple circular hatch closing off the end of the tube (though it will of course need those), but the *side* of the tube. It will have to be as big as the car so that you can remove and replace cars for maintenance. So that's a whopping great door in a whopping great airlock.

But it gets better. The tube will be hundreds of miles long running through the middle of bumfark nowhere. And you will need airlocks every... how far? Every hundred feet? Every hundred meters? When the inevitable happens and a car breaks down for *whatever* reason out in the middle of nowhere, you will need to not only stop the entire system, you'll need to be able to close off the section of tube the broken car is in in order to extract the passengers. Of course, since the car is broken down, you'll need to be able to extract the *car.*

Further: if a seal breaks *anywhere* in the system, you'll need to be able to close down the tube at nearly any point. Whether that break is due to a structural failure or somebody poking holes in it with armor piercing rounds, one thing you *don't* want is a major breach, the sort of thing that might be caused by a truck t-boning the tube, or a bomb either placed against the tube or carried *in* a tube-car, or a good sized earthquake (which California, if you were unaware, is reasonably famous for). Because then you'll have a plug of air rushing down the tube at Mach 1. This will overtake cars running away from it and accelerate them up to about Mach 1, slamming them into cars down the line. The air rushing head-on toward oncoming cars will hit at something like Mach 1.5, which will be like hitting a wall and turning the passengers into paste. The air will then push the car backwards like a paintball, straight into oncoming traffic.

So you'll need *lots* of airlocks (the more airlocks you have, the less volume in each section that needs to be pumped down... but the more airlocks you have, the more airlock *doors* and pumps and whatnot you'll need). And for every airlock, you'll need a pump powerful enough to draw down it's section in short order. And for every section you'll need one of those large vacuum-sealed doors big enough to extract passengers from. More to the point, you'll need to design the system so that every car out in the middle of nowhere can promptly *self* extract. Because you really don't want to leave paying customers in a small, dark, confined space inside of a vacuum chamber.

None of this is physically impossible. But is it practical? Is it financially supportable?

 

[Orionblamblam]

But i wont bother to change your mind on it. It is one thing to be skeptical and question the engineering (which is completely fine of course), it is another thing to outright dismiss something based on an extremely hyperbolic, obviously clickbaity 13 min youtube video.

I'm sorry you can't be bothered to try to understand the *real* technical problems and objections there are to the hyperloop concept, all because you don't like the tone of a well-known scientist who has done a pretty good job over the years of debunking nonsense.

 

[Anderman]

I don´t understand the whole competion part.
Why develop this pods if you can run something like the Transrapid in it?

https://en.wikipedia.org/wiki/Transrapid#Ecological_impact

 

[flanker]

But i wont bother to change your mind on it. It is one thing to be skeptical and question the engineering (which is completely fine of course), it is another thing to outright dismiss something based on an extremely hyperbolic, obviously clickbaity 13 min youtube video.

I'm sorry you can't be bothered to try to understand the *real* technical problems and objections there are to the hyperloop concept, all because you don't like the tone of a well-known scientist who has done a pretty good job over the years of debunking nonsense.

Oh, i can play this game too, you are making this too easy. Lets see;

"Well-known scientist" ranting on Youtube vs Elon Musk a billionaire that has made his fortune in easy stuff like banking, spaceflight and auto industry. + SpaceX engineers that worked on designing the hyperloop. + SpaceX engineers that worked on designing the test track. + Tesla engineers that designed and made the pusher. + Students applied for the competition. + Students that actually built the pods.

Clearly, they are all idiots. Clearly we are looking at even argument field here. All of them vs a guy on youtube.

The video arguments can be boiled down to three "points" he made against the system;

1; The track isnt as long as the suggested fully operational routes would be. No sh!t.
2; The pods in the track didnt achieve top speeds, never mind this is a student competition and the first one at that. No sh!t.
3; There was no airlock, again, see my previous statement, it was planned. So useless point based in arrogance and ignorance.

The rest of the video is passive aggressive wink-nudge-nudge whining.

 

[Orionblamblam]

Oh, i can play this game too, you are making this too easy. Lets see;

Look, I've been arguing online for a quarter century now, seemingly always playing the skeptical curmudgeon against the overly enthusiastic fanboys and outright cranks. And I gotta say, you're falling into the fanboy stereotype almost like you had a playbook.

Rather than ranting about How Dare An Outsider Argue Against My Experts, why don't you actually *counter* the actual arguments? Why don't yo do us the favor of running the numbers?

Such as: let's say you have an approximately 3.5-meter steel tube (which is about the diameter of the tube hyperloop is currently welding together to form another, larger test track). Your plan is to pump it down to about 0.1% of an atmosphere. How thick does the tube need to be to withstand external pressure against collapse? Now, how thick does it need to be once you factor in normal wear-and-tear dents? Assume everything from a vandal with a sledgehammer to a nut with a gun or a pipe bomb to a truck or plane crash.

Now, compare that thickness to the actual thickness of the tube that hyperloop is welding together. Here's a photo:

Note that X-brace inside? That's there to keep the tube from sagging under it's own weight... *before* it's pumped down. Once it's pumped down, that'll be another 14 or so pounds per square inch trying to crush it. Can it be made to work? Sure. But as Akin's Law #36 states:
Any run-of-the-mill engineer can design something which is elegant. A good engineer designs systems to be efficient. A great engineer designs them to be effective.
A good part of "effective" is that the hyperloop tube can be made not only adequately rugged, but reasonably inexpensive. These two tend to conflict. Especially when you factor in the need for not only periodic pressure doors to form airlocks, but also the innumerable car-sized hatches cut *sideways* into the tube.

Now, you can continue to rant about random internet nobodies... or you can man up and run the numbers and prove just how cheap all these problems will be to safely counter.

 

[BAROBA]

The thicker rings that the robot is welding will help withstand the pressure.
I don't think they will go cut holes in the side, the problems that will create are as Scott pointed out,correctly, enormous.
My idea:They will have to include servicestations and side-rails every so much miles in case of a breakdown. Which creates it own problems, but would be manageable(r). The Hyperloop is a nice idea, but in case of a problem, things get really nasty really quick. It reminds me of those floating big rings in space with a lot of glass and people walking around carefree.... Until something happens, and the architecture of the construction was never designed to deal with that kind of situation, and we all know what happens next....

Rob

 

[Michel Van]

Lately Elon Musk twittering about Hyperloop is associate with tunnel drilling.

Seems that final hyperloop concept will be similar to good old Vacuum Train design of 1960s:
a underground concrete Tube, it inside air pump is down to about 0.1% of an atmosphere.
so a Electromagnetic levitating Train fly at supersonic speeds true it.

But such concept have one in common: Reports on the question of economic viability are mostly negative.
Next enormous cost of drilling a tunnel from L.A. to San-Fran
Is also cost of electrical power needed for pumping air down to about 0.1% of an atmosphere and keep it like that.
also power the Train in tube
next to problem of safety if train got stuck in tube far away from station

What worry me most is that Hyperloop take students programs and not industrial engineers firms
Thunderf00t Youtube channel show me that ALL projects of New innovative technology were students were involved,
in designing that Hardware or verified it, goes no were or are cash burner
like infamous "Waterseer" project, who nothing else as a Ponzi scheme !

To make matter worst, at Hyperloop company happen a case of Mobbing and embezzlement by the Management.
http://fortune.com/2016/07/12/stunning-allegations-vs-hyperloop-execs/
https://www.ft.com/content/1d78b628-4874-11e6-8d68-72e9211e86ab

 

[Orionblamblam]

My idea:They will have to include servicestations and side-rails every so much miles in case of a breakdown. Which creates it own problems, but would be manageable(r).

Within certain limitations of the definition of "manageable."Technically feasible?" Sure. "Affordable?" Ah, now that's the thing.

 

[flanker]

Look, I've been arguing online for a quarter century now, seemingly always playing the skeptical curmudgeon against the overly enthusiastic fanboys and outright cranks. And I gotta say, you're falling into the fanboy stereotype almost like you had a playbook.

So i when i am using your tactic and flipping it, it is suddenly not ok? ;D I used your exact line of argument. And it is funny, because to me you are a stereotypical conspiracy theorists ala flat-earther/moon landing denier/global warming denier. Never mind people that know better than you. Never mind the evidence. Never mind common sense, this one youtube guy is surely right vs all of those dum dum engineers and bunch of nobodies.

Rather than ranting about How Dare An Outsider Argue Against My Experts, why don't you actually *counter* the actual arguments? Why don't yo do us the favor of running the numbers?

You do realize i did sum up his "arguments" just above, right? That is literally all of the arguments he made. As to running the numbers, you do know how the justice system works, right? Well, apply it then. The burden of proof is on your shoulders, not mine. You havent ran any numbers whatsoever to prove hyperloop wont work for whatever reason. Basically you want;

1; Make unsubstantiated claims.
2; Then ask ME to run the numbers to prove those unsubstantiated claims wrong.

Please.

Such as: let's say you have an approximately 3.5-meter steel tube (which is about the diameter of the tube hyperloop is currently welding together to form another, larger test track). Your plan is to pump it down to about 0.1% of an atmosphere. How thick does the tube need to be to withstand external pressure against collapse? Now, how thick does it need to be once you factor in normal wear-and-tear dents? Assume everything from a vandal with a sledgehammer to a nut with a gun or a pipe bomb to a truck or plane crash.

Now, compare that thickness to the actual thickness of the tube that hyperloop is welding together. Here's a photo:

Note that X-brace inside? That's there to keep the tube from sagging under it's own weight... *before* it's pumped down. Once it's pumped down, that'll be another 14 or so pounds per square inch trying to crush it. Can it be made to work? Sure. But as Akin's Law #36 states:
Any run-of-the-mill engineer can design something which is elegant. A good engineer designs systems to be efficient. A great engineer designs them to be effective.
A good part of "effective" is that the hyperloop tube can be made not only adequately rugged, but reasonably inexpensive. These two tend to conflict. Especially when you factor in the need for not only periodic pressure doors to form airlocks, but also the innumerable car-sized hatches cut *sideways* into the tube.

And with that it is extremely clear to me you havent even done the most basic bare bones research other than watching a clickbaity youtube video with 0 math. Because if you had, you would have seen this;

A tube wall thickness between 0.8and 0.9in.(20to 23mm) is necessary to provide sufficient strength for the load cases considered such as pressure differential, bending and buckling between pillars, loading due to the capsule weight and acceleration,as well as seismic considerations.

The tube wall thickness for the larger tube would be between 0.9and 1.0 in (23to 25mm).

http://www.spacex.com/sites/spacex/files/hyperloop_alpha-20130812.pdf

I will be waiting for your version of thickness needed, i am sure you will prove top nothing quality numbers.

Your requirements for the tube to withstand a plane crash are 100% asinine. Nobody is engineering railroads to withstand a plane crash... Or pretty much anything else other than possibly skyscrapers and probably not even all of them.

As to the brace, what is your point exactly? Are you trying to tell me a short, floppy tube with a large diameter and couple of cm thick just might need internal brace for transport? Stop the press, this is breaking news. Surely this has never happened before.

Now, you can continue to rant about random internet nobodies... or you can man up and run the numbers and prove just how cheap all these problems will be to safely counter.

Once again. YOU are the one that is making unsubstantiated claims. YOU are the one that has provided nothing whatsoever that falls under "running the numbers". Also note, your terrible video provided 0 numbers too.

 

[Orionblamblam]

Lately Elon Musk twittering about Hyperloop is associate with tunnel drilling.

But such concept have one in common: Reports on the question of economic viability are mostly negative.
Next enormous cost of drilling a tunnel from L.A. to San-Fran

Putting it underground would solve a lot of problems. it would also introduce a whole bunch of new ones, cost being driven up profoundly being one. Another? Drilling a tunnel through earthquake country is generally not a fantastic idea.

next to problem of safety if train got stuck in tube far away from station

A problem occurs, like, say, an earthquake shearing the tunnel, popping the vacuum and cutting the power, could leave a whole bunch of cars stuck. According to www.spacex.com/sites/spacex/files/hyperloop_alpha-20130812.pdf, there's a separation distance of 23 miles between cars; in an LA-SF run of 350 miles, that'd be 15 cars in *each* direction, so, 30. Assuming the cars stop evenly they'll be 23 miles from each other.

If you design the thing with the assumption that every now and then a car will stop and will need to be removed, you'll need to design in a way to extract a car every so many miles. Or you'll need to design the cars so that one can push a dead one all the way to the end terminal.

All possible. All ugly.


History is replete with really smart people falling in love with one of their own ideas, and pushing it *long* past the point where they should have realized that it's just not practical. Is Hyperloop the same thing? Maybe. it's kinda looking like it. And what's worse, when the really smart person is really charismatic or really successful, they can surround themselves with a whole lot of fans who either cannot understand the flaws, or who choose not to.

Akin's Law #4. Your best design efforts will inevitably wind up being useless in the final design. Learn to live with the disappointment.

That's something *everybody* has trouble with. Having been there, I can assure you that it is a particular issue for teens and college age kids. Maybe something something Millenial Snowflakes Especially Bad, but rest assured that it has *always* been a problem.

 

[Graham1973]

Lately Elon Musk twittering about Hyperloop is associate with tunnel drilling.

Seems that final hyperloop concept will be similar to good old Vacuum Train design of 1960s:
a underground concrete Tube, it inside air pump is down to about 0.1% of an atmosphere.
so a Electromagnetic levitating Train fly at supersonic speeds true it.

I have memories of reading about those things in one of those 'Useborne Books of the Future' back when I was growing up. Every time I read about Hyperloop that's what I kept thinking, that the idea was not new, just the hoopla.

And here is the latest missive from Thunderf00t (His series on the Fontus 'Self Filling Waterbottle' is also worth looking at.):

https://www.youtube.com/watch?v=Z48pSwiDLIM

 

[Orionblamblam]

Look, I've been arguing online for a quarter century now, seemingly always playing the skeptical curmudgeon against the overly enthusiastic fanboys and outright cranks. And I gotta say, you're falling into the fanboy stereotype almost like you had a playbook.

So i when i am using your tactic and flipping it, it is suddenly not ok?

My "tactic" is skepticism. How is it that *you* are using skepticism when you are uncritically accepting public relations?

And it is funny, because to me you are a stereotypical conspiracy theorists ala flat-earther/moon landing denier/global warming denier.

OK, yeah, there's no point trying to debate you, when you are *clearly* utterly delusional. Welcome to "ignore."

 

[TomcatViP]

Funny and refreshing. Critics can be caustic (and have to be).

They are using the wrong construction strategy.
Segmented linear construction such as is rail was a strategy to cope with slope and curve changes that had to diverge from terrain configuration. Discreet alteration of angles are more easily managed over long distance than a continuous change, such as seen with road (road vehicles have less stringent adaptation requirement to terrain contours).

Here, the intention is go straight line from A to B... So why bother with the difficulties of segmented construction when each segment impart a degree of inaccuracy upon every other ?

Continuous tunnel setup is the way to go. There are possibilities for this.

 

[flanker]

My "tactic" is skepticism. How is it that *you* are using skepticism when you are uncritically accepting public relations?

Again as i said previously;

It is one thing to be skeptical and question the engineering (which is completely fine of course), it is another thing to outright dismiss something based on an extremely hyperbolic, obviously clickbaity 13 min youtube video.

OK, yeah, there's no point trying to debate you, when you are *clearly* utterly delusional. Welcome to "ignore."

Cute. ;D Your argument in its entirety is to copy a youtube guy who has some extremely weak arguments and no understanding what the test track built by SpaceX is for. You are the one that is completely dismissing literally hundreds of people that has worked and done actual math so far on this idea including, and this bears repeating;

- Elon Musk, a self made billionaire that has made his fortune in easy stuff like banking, spaceflight and auto industry.
- SpaceX engineers that worked on designing the hyperloop and writing the alpha paper.
- SpaceX engineers that worked on designing the test track.
- Tesla engineers that designed and made the pusher.
- Students that applied for the competition.
- Students that actually built the pods.
- The different companies working on this including hyperloop one and hyperloop transportation technologies.

But you and your youtube guy knows better of course. Just like a flat earther on youtube knows better. Or moon landing denier knows better than NASA, basically whole civilized world and the thousands of people that worked on Apollo. Or you knowing that global warming is a hoax based on it snowing outside your own door. My comparison of your thinking vs those groups is directly comparable. Very mature to take your toys home and put me to ignore, but whatever.

 

[Orionblamblam]

And here is the latest missive from Thunderf00t (His series on the Fontus 'Self Filling Waterbottle' is also worth looking at.):

A few videos back he pointed out why he's becoming a bit more "clickbaity." Normally clickbait is bad, but here I agree with him. BS like the "WaterSeer" and the "Solar Roadways" and the "Fontus" get lots and lots of free press, and lots and lots and lots of investment and crowdfunding... yet videos and data that debunk them *don't* get that free press, and are barely noticed in comparison. So by going clickbaity, Thunderf00t is hoping to increase the viewership of debunkings.

This has long been a problem in the world at large. Jonathan Swift pointed out in 1710:

Besides, as the vilest Writer has his Readers, so the greatest Liar has his Believers; and it often happens, that if a Lie be believ’d only for an Hour, it has done its Work, and there is no farther occasion for it. Falsehood flies, and the Truth comes limping after it; so that when Men come to be undeceiv’d, it is too late; the Jest is over, and the Tale has had its Effect…

 

[Orionblamblam]

So why bother with the difficulties of segmented construction when each segment impart a degree of inaccuracy upon every other ?

Continuous tunnel setup is the way to go.

Building a seamless steel tube 300+ miles long and several meters in diameter would be a non-trivial feat. Also: steel, like pretty much everything, expands and contracts with temperature.

Math: thermal expansion coefficient for steel is about 8*10-6 in/(in R). This means if a one-inch long piece of steel gets 40 degrees F warmer, it'll get 0.00032 inches longer. Big whoop. But if you lengthen that piece of steel to 350 *miles,* it'll get 40*350*5280*12*8*10-6 = 7096 inches longer. That's 591 feet, or 180 meters. That means that a single tube, or a series of tubes firmly bolted/welded together, will expand enough during the course of a single *day* that the ends of the terminals will move... well, a lot.

If you bury the tube underground, the temperature changes will be greatly reduced, of course. And you can always insulate and actively heat/cool the tube to maintain a specific temperature. These all cost money. Or you can accept the temperature differential, and simply clamp the tube to it's pylons *real* hard. This can prevent expansion, at the expense of greatly shortened lifespan as the tube stresses itself into garbage. Or you can design in expansion joints here and there... every modern steel bridge you've ever driven across has a few of these. But for the hyperloop, these expansion joints will need to be telescoping tubes that through all temperatures, over times and with the effects of rust and dust and dirt, can somehow hold a vacuum. This... costs money.

A single steel tube can't have expansion joints, of course.

 

[sublight_]

Building a seamless steel tube 300+ miles long and several meters in diameter would be a non-trivial feat. Also: steel, like pretty much everything, expands and contracts with temperature.

Thank god we never built any oil pipelines or really high pressure gas pipelines out of them then....

 

[overscan (PaulMM)]

Lets try to keep this more civil, please!

In my opinion, there are significant technical hurdles to making such a system, but they aren't insurmountable. Its a vision to make something truly revolutionary - thats where innovators like Musk excel. Its in some way like the moon landings. There were a lot of technical hurdles to be overcome in that project too, which were overcome ( albeit at a tremendous financial cost). Musk and his companies aren't actually planning to build a Hyperloop at all, its a idea he's thrown out there with a bit of preliminary engineering done to show it's not completely impossible. Not sure why it's provoking such animus.

 

[overscan (PaulMM)]

Building a seamless steel tube 300+ miles long and several meters in diameter would be a non-trivial feat. Also: steel, like pretty much everything, expands and contracts with temperature.

Thank god we never built any oil pipelines or really high pressure gas pipelines out of them then....

Which of course never leak.... transporting people requires higher standards...

 

[CJGibson]

http://www.ikbrunel.org.uk/atmospheric-railway

Same problem, at a slower pace.

Chris

 

[Orionblamblam]

Building a seamless steel tube 300+ miles long and several meters in diameter would be a non-trivial feat. Also: steel, like pretty much everything, expands and contracts with temperature.

Thank god we never built any oil pipelines or really high pressure gas pipelines out of them then....

I'm not sure if you are parodying ignorance, or displaying it. In either event, in case anyone thinks these are actually comparable... they're not. Oil and gas moves at dozens of miles per hour, and doesn't care much if it hits bumps. So if a pipeline bends and flexes a bit, so long as it doesn't spring a leak, nobody cares. But a tube in which *humans* are traveling at approximately Mach 0.9? You kinda want to keep bumps to a bare minimum. At those speeds, even a small bump could jolt the car up or over a few inches... where there happens to be a wall. A small bump at Mach 0.9 would put substantial stress on the systems attempting to keep the car on the track. It would tend to rattle the passengers around inside the car like a handful of buckshot in a beer bottle.

Oil and gas pipelines are generally built to follow the terrain. They are *already* bent and curved. So the normal course of thermal expansion simply fits into the existing bending. But if you want to keep it arrow-straight for hundreds of miles... well, if you're okay with pouring the passengers out the far end like reddish petroleum... go for it!

 

[Anderman]

I don´t understand why Hyperloop is called innovative or revolutionary ? The idea is very old

https://en.wikipedia.org/wiki/Vactrain

 

[Orionblamblam]

Its in some way like the moon landings. There were a lot of technical hurdles to be overcome in that project too, which were overcome ( albeit at a tremendous financial cost).

The thing is... Apollo did something entirely new. Hyperloop, even if it works as advertised, is simply another way to get from A to B. The claim is that it'll be a lot faster than current systems, but that can only work if things work in some perfect world of unicorn farts and no TSA.

Not sure why it's provoking such animus.

Some people get emotionally invested in things that they either really like or really don't, but haven't really done the math on. You think this is bad, go tell the fanboys/fangirls that "Batman V Superman was second in sheer awesomeness only to Batman Forever."

 

[Arjen]

Not sure why it's provoking such animus.

It's a lifestyle thing

 

[flanker]

I don´t understand why Hyperloop is called innovative or revolutionary ? The idea is very old

https://en.wikipedia.org/wiki/Vactrain

It is not directly the same. Read the alpha paper;

http://www.spacex.com/sites/spacex/files/hyperloop_alpha-20130812.pdf

The key is the Kantrowitz Limit and how the plan is to overcome it.

Some people get emotionally invested in things that they either really like or really don't, but haven't really done the math on.

Pot calling the kettle black.

 

[sferrin]

So why bother with the difficulties of segmented construction when each segment impart a degree of inaccuracy upon every other ?

Continuous tunnel setup is the way to go.

Building a seamless steel tube 300+ miles long and several meters in diameter would be a non-trivial feat. Also: steel, like pretty much everything, expands and contracts with temperature.

Math: thermal expansion coefficient for steel is about 8*10-6 in/(in R). This means if a one-inch long piece of steel gets 40 degrees F warmer, it'll get 0.00032 inches longer. Big whoop. But if you lengthen that piece of steel to 350 *miles,* it'll get 40*350*5280*12*8*10-6 = 7096 inches longer. That's 591 feet, or 180 meters. That means that a single tube, or a series of tubes firmly bolted/welded together, will expand enough during the course of a single *day* that the ends of the terminals will move... well, a lot.

You'd have gaps at either end of the tubes so they "float" within seals at the ends of each tube. The sealing rings are built into the supports at each end of tubing. Of course that's a metric fookton of seals but that's how they'd do it.

 

[BAROBA]

So why bother with the difficulties of segmented construction when each segment impart a degree of inaccuracy upon every other ?

Continuous tunnel setup is the way to go.

Building a seamless steel tube 300+ miles long and several meters in diameter would be a non-trivial feat. Also: steel, like pretty much everything, expands and contracts with temperature.

Math: thermal expansion coefficient for steel is about 8*10-6 in/(in R). This means if a one-inch long piece of steel gets 40 degrees F warmer, it'll get 0.00032 inches longer. Big whoop. But if you lengthen that piece of steel to 350 *miles,* it'll get 40*350*5280*12*8*10-6 = 7096 inches longer. That's 591 feet, or 180 meters. That means that a single tube, or a series of tubes firmly bolted/welded together, will expand enough during the course of a single *day* that the ends of the terminals will move... well, a lot.

You'd have gaps at either end of the tubes so they "float" within seals at the ends of each tube. The sealing rings are built into the supports at each end of tubing. Of course that's a metric fookton of seals but that's how they'd do it.

I think you are missing the point here: You can not build a station or pod-extraction point anywhere along the line. Because in the winter it is like 591 feet or 180 meters further from its summer position.
How much would the diameter change between winter and summer? Seals and such would need to be quite flexible.

Has anyone calculated if this is worth the effort? How much power does a Japanese bullettrain (on maglev) need compared to this system?

I have a cheaper alternative Put your people in your pod, no need for a pusher.Make a not-so-low vacuumtube. Seal it.
Then break the seal behind the pod and BANG the pod gets pushed through the tube, pushed by the air rushing in but not able to pass the pod thanks to a shield.

 

[Orionblamblam]

I have a cheaper alternative Put your people in your pod, no need for a pusher.Make a not-so-low vacuumtube. Seal it.
Then break the seal behind the pod and BANG the pod gets pushed through the tube, pushed by the air rushing in but not able to pass the pod thanks to a shield.

I have a cheaper-yet alternative. Put your people in your pod... then bolts wings and turboprops or turbofans to it, then fly it where you want to go. not only do you not have to build the tube between points A and B, you can fly the pod to Points C, D, E, F....

 

[VTOLicious]

Maybe the Airforce can help out :

"The U.S. Air Force set a new world speed record for magnetically levitated sled systems (MagLev) sending a rocket propelled sled down a 2100 ft track reaching 633 mph (1018.71 Km/h) at Holloman AFB on March 4, 2016."

https://www.youtube.com/watch?v=MF1trVf-6rw

 

[bobbymike]

https://www.sciencealert.com/the-winner-of-elon-musk-s-hyperloop-pod-competition-just-hit-an-astonishing-speed-record-290-miles-an-hour

WARR Hyperloop, from the Technical University of Munich, won first place for the third time in a row and simultaneously set new speed records, topping out at 290 miles per hour (466 kilometre per hour).

This year's competition was exclusively focused on developing maximum speed pods, with the only requirements being that all pods be self-propelled as they raced to see who could travel the fastest down a 0.8 mile (1.3 kilometre) long test track tunnel from a standstill.

The annual competition drew 20 entrants from all around the world, and was hosted at SpaceX headquarters in Hawthorne, California. SpaceX CEO Elon Musk attended the event, along with his partner, Grimes, the Canadian pop star.

Originally announced in 2015, Musk's annual Hyperloop Competition seeks to cultivate engineering talent while simultaneously developing innovations for a futuristic transportation system. It is the first competition of its kind anywhere in the world.

 

[Grey Havoc]

Given other current events, it will be interesting to see if this goes anywhere:
https://www.mercurynews.com/2018/09/12/boring-company-earns-approval-for-futuristic-garage/
https://tech.slashdot.org/story/18/09/13/0410245/boring-company-approved-to-build-futuristic-garage-that-would-connect-to-underground-commuter-tunnel

 

[sferrin]

Given other current events, it will be interesting to see if this goes anywhere:
https://www.mercurynews.com/2018/09/12/boring-company-earns-approval-for-futuristic-garage/
https://tech.slashdot.org/story/18/09/13/0410245/boring-company-approved-to-build-futuristic-garage-that-would-connect-to-underground-commuter-tunnel

The only people who care about Elon taking a drag are the MSM who can get a headline. Tesla stock is already back to pre-puff levels.

 

[Grey Havoc]

I'm not so sure. We'll see, I suppose.


In other news (from July and August respectively):

Canadian start-up seeks French testing ground for hyperloop train (SpaceDaily.com)

760-mph hyperloop from Ohio to Chicago moves closer with new regulations (Dayton Daily News)

 

[sferrin]

I'm not so sure. We'll see, I suppose.

All you have to do is look. #ElonPuff happened on Sept 6th.