Hyperloop One Reveals Test Track Progress (computerworld.com.au)

Hyperloop One has released the first photographs of its "proof of concept" test track near Las Vegas, Nevada, and there's now also a couple short videos online. Slashdot reader angry tapir quotes Computerworld: The company revealed its progress on Tuesday at the Middle East Rail conference in Dubai, sharing pictures and footage of its Nevada development site dubbed "DevLoop." Taking Elon Musk's Hyperloop concept of a levitating pod in a low-pressure tube, Hyperloop One has developed what is so far the only full-scale, full-system Hyperloop test site...and says it plans to test the entire apparatus this year.
In addition, Investopedia reports that Hyperloop One has now also signed letter of intent agreements to investigate the feasibility of building more hyperloop systems in Finland and the Netherlands.

Comments

Emergencies?

[sycodon]

Looking at photos of the test track, you have to wonder how the hell do you get out if something goes wrong?

What happens if there is a sudden "repressurization"? Seems to me that would be like hitting a brick wall at the speeds they are talking about.

What if the motive element fails and the pod comes to a halt? There you are, stuck in a sealed tube.

Re:Emergencies?

[JustAnotherOldGuy]

Looking at photos of the test track, you have to wonder how the hell do you get out if something goes wrong?

You cut the bodies out with the Jaws of Life and vacuum up the remains with a ShopVac.

-

What happens if there is a sudden "repressurization"?

You cut the bodies out with the Jaws of Life and vacuum up the remains with a ShopVac.

-

What if the motive element fails and the pod comes to a halt? There you are, stuck in a sealed tube.

You cut the bodies out with the Jaws of Life and cart them away on gurneys.

Re:Emergencies?

[religionofpeas]

How do you get out of an airplane when something goes wrong ?

Re:Emergencies?

[haruchai]

How do you get out of an airplane when something goes wrong ?

Parachute or ejection seat for the important people.

Re:Emergencies?

[amiga3D]

Sure, try jumping out with a parachute at 30K feet from a jetliner running 550 knots. I did see one design for a commercial passenger jet with ejectable modules for all passengers. A ticket in something like that from NY to LA would run about 50 thousand dollars. Considering air travel is safer than any form of land travel on a passenger mile basis I guess they decided to forgo the expense.

Re:Emergencies?

[s.petry]

Airplanes don't fly through solid steel tubes that have to be able to withstand massive amounts of pressure from a vacuum. There is no recovery from accidents if Hyperloop was to get off the ground, and to be honest I don't believe this project will work. Thunderf00t has done some validation of this project, or should I say shown major failure points.

Interesting ideas don't always pan out.

Re:Emergencies?

[Zocalo]

...able to withstand massive amounts of pressure from a vacuum.

I never cease to be amazed how many people think vacuum exerts a massive amount of pressure; Hollywood has a *LOT* to answer for for all those ridiculous explosive decompression scenes. The pressure between hard vacuum and atmosphere at sea level is exactly 1 atmosphere; you can get more pressure differential in a typical swimming pool. There's a reason spacecraft are about as rigid as a tin can and submarines are built out of many tonnes of steel and titanium, and it's that one has to deal with some pressure and the other... doesn't. If anything, the tube of the hyperloop is likely to be under more stress from the capilliary action of the vehicles (are we going with rail terminology and calling them "cars" or something else?) and bowshock in the less than perfect vacuum then pressure from the external atmosphere.

Re:Emergencies?

[bill_mcgonigle]

I did see one design for a commercial passenger jet with ejectable modules for all passengers. A ticket in something like that from NY to LA would run about 50 thousand dollars.

Don't do it individually, put the whole cabin on parachutes.

This guy has an update on that old idea with rear-exit and rocket-assisted landing:
https://www.liveleak.com/view?...

Re:Emergencies?

[JustAnotherOldGuy]

How do you get out of an airplane when something goes wrong ?

A lot of the time you don't. How many airplane crashes have you been in, and how many have you survived?

Re:Emergencies?

[religionofpeas]

Airplanes don't fly through solid steel tubes that have to be able to withstand massive amounts of pressure from a vacuum

Correct, but hyperloop pods don't suck birds into their engines. My point was not to claim that planes and hyperloop pods are identical, just that planes are also very limited in the way they can recover from accidents mid-flight, yet that hasn't stopped people from using them.

Re:Emergencies?

[chispito]

massive amounts of pressure from a vacuum.

It's not that much pressure.

Re:Emergencies?

[religionofpeas]

That was the point, yes.

Re:Emergencies?

[Teun]

I agree with you vacuum is not a particular big pressure differential to overcome.
But it would be a rather deep pool to get an similar differential, 1 atmosphere/bar (14.5 psi) is equivalent to 10 meters (30 ft) of water depth.
If this thing gets build in a place like The Netherlands it would no doubt be an underground tube and the forces of the overbearing soil and water are greater than the vacuum.
In such a construction most of the tube would be a regular concrete structure with something thin made of steel or plastic to make it air tight.
Yes there'll be a bow shock but easy to calculate and construct accordingly.

Re:Emergencies?

[Hardness]

"In Hyperloop, no one can hear you scream."

Re:Emergencies?

[JustAnotherOldGuy]

I never cease to be amazed how many people think vacuum exerts a massive amount of pressure; Hollywood has a *LOT* to answer for for all those ridiculous explosive decompression scenes.

In space the pressure is an outward force, in atmosphere it's an inward force.

Vacuum can create the exertion a LOT of pressure. Try the old experiment where you lay a ruler hanging halfway off of a table and cover the end on the table with a sheet of newspaper. Now bang on the end of the ruler that's off the table and see what happens. The ruler stays right where it is because the pressure of the air against the newspaper is actually very significant. Figure 15lbs per sq inch on a 20"x20" sheet of paper (400 sq inches) is 6000 lbs.

People who haven't seen this demonstration are always shocked when the ruler doesn't fly up and take the newspaper with it. You're much more likely to break the ruler off at the edge of the table. Try it if you don't believe me.

Or if you're lazy, watch a demonstration here: https://www.youtube.com/watch?...

I worked with high vacuum quite a bit in my younger days and the forces involved can be immense. The forces involved with the hyperloop are really quite insane and the possibility of an accident is very, very high. The results could be catastrophic to say the least.

Re:Emergencies?

[nukenerd]

...able to withstand massive amounts of pressure from a vacuum.

I never cease to be amazed how many people think vacuum exerts a massive amount of pressure

I think his point was that there is a tube to escape out of, irrespective of how "massive" or otherwise the pressure is.

Re:Emergencies?

[JustAnotherOldGuy]

That was the point, yes.

No, the point is that airplane accidents involve forces that normally preclude survival. JUst like with a hyperloop track.

Survive a plane crash or two and get back to me, then I might take you seriously.

Re:Emergencies?

[sycodon]

Nice.

Re:Emergencies?

[religionofpeas]

No, the point is that airplane accidents involve forces that normally preclude survival. JUst like with a hyperloop track.

Exactly my point, yes. And despite the grim outlook, millions of planes fly every year with very few deadly accidents.

Re:Emergencies?

[religionofpeas]

In space the pressure is an outward force, in atmosphere it's an inward force.

For steel, the compressive and tensile strengths are similar, so it doesn't really matter.

Re:Emergencies?

[angel'o'sphere]

No, the point is that airplane accidents involve forces that normally preclude survival. JUst like with a hyperloop track.

The hyperloop has no such forces. You are an idiot.

Re:Emergencies?

[Anonymous Coward]

You are probably not far off

https://www.youtube.com/watch?...

Re:Emergencies?

[Gorobei]

There's a reason spacecraft are about as rigid as a tin can and submarines are built out of many tonnes of steel and titanium, and it's that one has to deal with some pressure and the other... doesn't.

Actually, the reason is a bit different: round things with excess pressure on the inside respond by getting more round and keeping their shape (think latex balloons being inflated;) round things with excess pressure on the outside respond by getting more oval/ flattish and losing their shape

So, for negative pressure things, you have to design them to avoid collapse, not true for positive pressure things. A spacecraft hull (say a dime's thickness of aluminum) can easily handle 5 atmos of pressure differential. Put it 30 feet underwater, and it will collapse like a cheap suit in the -1 atmo environment.

Re:Emergencies?

[mobby_6kl]

That's not true at all, most airplane accidents are very survivable. There are of course those few you see on the news where the plane blows up mid-air or plummets into the ground at mach 2 and they have to count the passengers by the number of teeth found.

But overall, even including serious cases with fire or other extensive damage to the airframe, the survivability rate is almost 80%.

Thankfully, very few people are even among those 80%, because mishaps are so rare, so there's nobody around to talk about it. Just like with hyperloop, which will have way less stuff to fail, and the failure modes are way more forgiving. Like, being stuck for a while.

Re:Emergencies?

[lgw]

Because it is rather difficult to completly crash a whole plane in a single moment,

Funny, I was under the impression that's what always happens when plane meets ground energetically. Lithobraking is rather abrupt that way.

Re:Emergencies?

[religionofpeas]

Because it is rather difficult to completly crash a whole plane in a single moment

You mean to say that sometimes the front half of the plane crashes, but the rear section continues to fly and land safely at the destination ?

Re:Emergencies?

[thinkwaitfast]

At the volumes they're talking about, I think it would take half an hour to fill even it they cut the tube in two.

Re:Emergencies?

[nukenerd]

In space the pressure is an outward force, in atmosphere it's an inward force.

For steel, the compressive and tensile strengths are similar, so it doesn't really matter.

Yes it does matter, it is not as simple as the failure stress.

Under compression, as the vacuum tube will be, the structure can buckle. What starts off as a small variation from the round shape (even the minutest manufacturing departure from a pure circle) causes a further small distortion which escalates by positive feedback, even though the material is at first still well within its failure limit (and even within its elastic limit). Then, as the distortion gets more and more, the material eventually reaches its failure stress (starting "plastic" distortion in the case of steel). That is called buckling. This would not happen under internal pressure, which would keep a tube circular.

A steel tube would stand a much greater pressure difference if the greater pressure were inside rather than outside.

Re:Emergencies?

[Anonymous Coward]

Oh I am sure he is off on a few things. But the catastrophic collapse is not a 'maybe'. Just some simple demonstrations show that. The point is is if you are in that area of collapse you will be mashed like a bug as several thousand tons of air/metal collapse on you. Elsewhere in the system you will suddenly come to a screeching halt as the rupture will be quite large too. He also has other demonstrations of the bullet like effect air has. His description of 'wall of air' is probably not terribly off. The atmosphere is quite large and heavy. There is a gradient but it will be negligible. They are talking near evacuation levels. Its the old addage 'nature abhors a vacuum'. Any vehicles in the system will be pushed along like a bullet shot out of a gun.

Also none of the demonstrations have shown how people/vehicles will enter/leave the system. None of the demonstrations show how they are going to deal with long runs of this over earthquake territory. How do we get people out if the system eats itself?

Sure it is 'in progress' but these challenges are not even being talked about and are being dismissed out of hand.

Here is a demonstration of what he is talking about. Now more than likely the air would get past the cars in the rest of the system but it would be a wild ride... If the cars managed to stay on the track. If they ripped off the track (likely) they would basically flip end on end and create another rupture point.
https://www.youtube.com/watch?v=FoG9Dc1YVLY

Now dont get me wrong I want it to work. It will be amazing if they get it to work. Thunderf00t has some very serious concerns that need to be addressed. Even if they are wrong. They still need to be properly and scientifically addressed.

Re:Emergencies?

[rastos1]

a) true, the pressure is 1atm. On how big area? What force does that mean?

b) the scenario that is, in my opinion, dangerous, is a rupture of the capsule that is pressurized to 1atm surrounded by near vacuum. Followed by a collapse of the tube that results from the pieces of the capsule flying in all directions.

However the biggest problem I see from my chair is keeping a relatively fragile tube stretching hundreds of kilometers airtight, undamaged and secure from pissed farmers, drunk idiots, gun fans, vandals and other similar factors.

Re:Emergencies?

[radarskiy]

-1, physically incorrect description of phenomenon

What is being demonstrated in that video is drag, not air pressure. If you pushed the ruler down slowly the ruler does not break since drag force is a function of velocity squared.

Note that the air pressure on the bottom of the sheet of paper is the same as on the top.

Re:Emergencies?

[radarskiy]

Since the tube at negative pressure with respect to ambient, most panels don't need strong fasteners to maintain the seal. It's actually quite possible to build in emergency access that automatically opens by passive means in the even of a represurization incident.

Re:Emergencies?

[JustAnotherOldGuy]

Just like with hyperloop, which will have way less stuff to fail, and the failure modes are way more forgiving. Like, being stuck for a while.

The difference between airplanes and the hyperloop is that airplanes can be built.

Re:Emergencies?

[JustAnotherOldGuy]

The hyperloop has no such forces.

Seriously, do you even know what we're talking about? Because it sure doesn't sound like it.

Re:Emergencies?

[roman_mir]

When something goes wrong with an airplane other airplanes can still fly, the entire transportation system does not get shut down and other planes don't get damaged. If something goes wrong inside a vacuum tube with fast cars in it, if a car hits the tube at 1000 km/h, the air coming in will destroy all cars in the tube.

A plane without engines can still land by the way, even on water, once it lands people can leave it. If you need to escape a car, how do you escape the metal tube?

Re:Emergencies?

[JustAnotherOldGuy]

Hyperloop tube gets a hole. Air streams in. Air slows down the cabin, probably to a halt.

Yes, just like in this demo: https://www.youtube.com/watch?...

Shoot a hole in that tank before it undergoes collapse and you'll have a violent decompression, not some gentle "air streams in" scenario.

As someone said below, "Instead of denying science, do us all a favor and prove Thunderf00t and the Mythbusters wrong with your pseudo science."

Re:Emergencies?

[mobby_6kl]

The difference between airplanes and the hyperloop is that airplanes can be built.

I'm sure the hyperloop can be built too, we just know it won't fly. Hopefully.

Re:Emergencies?

[JustAnotherOldGuy]

And despite the grim outlook, millions of planes fly every year with very few deadly accidents.

And despite your cheerleading, it'll never be built to any real scale or carry passengers in any quantity over any distance. It's sounds like a cool idea, but it's not practical.

Why don't you just zoom down to the test site in your flying car, check it out and report back on the progress?

Re:Emergencies?

[JustAnotherOldGuy]

I'm sure the hyperloop can be built too, we just know it won't fly. Hopefully.

Why hasn't it been done before and why isn't it in wide use today?

If it's practical to do then hyperloops should be all over the place, but they aren't. Why is that?

Re:Emergencies?

[vtcodger]

"The forces involved with the hyperloop are really quite insane and the possibility of an accident is very, very high."

We do build ships that draw 10 or 15 meters without the hull collapsing (As long as they don't run into a rock). And submarines. And the pipes used in big hydroelectric dams are often subjected to much greater (albeit high pressure on the inside, not outside) pressure differentials. So the tubes are probably doable.

OTOH, what happens if the tube develops a crease because of an earthquake or supports washing out or some such. I have to believe that a transport capsule grazing a bent tube wall at many hundreds of km/hr are likely going to resemble those of a surface vehicle trying to go under a bridge with insufficient clearance while traveling at speed.

There will surely be accidents. The question is -- how many?

Re:Emergencies?

[Rei]

In what way, shape, or form?

As per the Hyperloop Alpha document, there are regularly spaced emergency exits. A vehicle brakes to low speeds, where it lowers onto its wheels and drives to the nearest emergency exit. Meanwhile, the valves are opened to slowly repressurize the tube along its length. Inside the cabin there's an emergency oxygen supply, like on an airplane.

What part of this do you find problematic?

Re:Emergencies?

[Rei]

Why on Earth did you just link to a video that explicitly states that the vehicle they're collapsing was not designed to tolerate vacuum? A vehicle made of thin-walled steel which even despite not being designed to contain vacuum, still stopped the collapse from propagating all the way down its length?

Whenever some topics come up on Slashdot, people get into this mode where they think that engineers are morons. As if engineers just sit around and go, "Hey, let's make some arbitrary pipe and subject it to arbitrary conditions and not even bother to check what's required to prevent the primary type of failure scenario it could undergo. Because that's totally what we engineers do as a job!"

Re:Emergencies?

[Rei]

You (and everyone else commenting on this thread) should actually read the design document before commenting (it never ceases me how many people want to pontificate about it without ever having read the bloody design document itself). Earthquakes take up a good bit of the document (they even do FEM sims). As per the specs in Hyperloop Alpha, the tube is not rigidly mounted to the supports; it's mounted to multiaxis dampers that adjust to maintain the tube in the same place. The tube is also floated (allowed to slip freely) lengthwise between the dampers for thermal expansion (one of the three common ways engineers use to deal with thermal expansion - the others being to resist it by force, or to accept deformation within given specs; "resisting" is more however common in high speed transport, with high speed rail tracks often laid in tension, so that thermal expansion just relieves stress).

Now, it looks like Hyperloop One is not to the point of testing the damper system yet. But that is what the design lays out.

Re:Emergencies?

[Rei]

Also, for the record, the total loss of one entire would 16x the gravity-related bending (double the length, and peak deformation is generally related to the unsupported length to the fourth power). But given that span lengths are designed so that there is no noticeable jolting at all between spans, 16x of "almost nothing" does not equal "catastrophe". Air bearings have highly nonlinear responses to changes in distance from the surface, and the bearings themselves are mounted on shock absorbers.

Re:Emergencies?

[Rei]

Right. Because large unsupported spans of thin aircraft aluminum is totally the same thing as inch-thick steel with reinforcement rings. Totally!

Re:Emergencies?

[Rei]

When something goes wrong with an airplane other airplanes can still fly, the entire transportation system does not get shut down and other planes don't get damaged.

That would be a great analogy if a single hyperloop tube between two points was equivalent to "the entire (air) transportation system".

The analogy is with a single air route between two destinations. And storms shut those down all the freaking time.

If something goes wrong inside a vacuum tube with fast cars in it, if a car hits the tube at 1000 km/h, the air coming in will destroy all cars in the tube.

In a world of imaginary physics where air flows instantly at mach 80 at full atmospheric density and viscosity and limiting shocks cease to play a role, indeed!

Meanwhile, in the real world, such shocks move at about mach 4 (aka taking several minutes to move down the tube), lose energy as they go, and do not suddenly repressurize the tube. Air still has to flow in through a highly confined orifice (aka small cross section relative to length). In cartoon physics this may happen instantly, but in the real world, a very long length to diameter ratio means significant time for pressure to equalize.

A plane without engines can still land by the way,

Sometimes. But it's more often a disaster. Everybody remembers the "Miracle in the Hudson", but of the previous two full-engine loss flights, Tuninter Flight 1153 killed 16/39 and Helios Airways Flight 522 killed 121/121; of the subsequent two, TransAsia Airways Flight 235 killed 43/58 and LaMia Flight 2933 killed 71/77.

By contrast, tube breach in Hyperloop, by design, results in the opening of valves to evenly pressurize the tube across its length (signals, unlike shocks, move at the speed of light), with vehicles braking to a stop and driving to the nearest emergency exit.

Re:Emergencies?

[Solandri]

The energy from pressurization is pressure * volume. At a 2.23m diameter (3.906 m^2 cross-sectional area), every km of tube pumped to 95% vacuum represents 376 MJ of energy. With an estimated 500 miles of tube, this represents 188 GJ, or about as much energy as 45 tons of TNT. Granted it's spread out over 500 km so is equivalent to about 82 grams of TNT per meter. That's not an insubstantial amount of energy. But I think a steel tube could be designed to withstand it.

The problem is what happens when a train car traveling 700 mph hits a section of tube damaged by a localized implosion. If a section of tube were somehow weakened, it would fail when the stresses it experienced were highest. This would probably be right when the first car of a train passed it. The weakened section fails inward, and the following train cars hit it at 700 mph.

Yes we fly 500+ mph in planes every day. But those planes don't fly a few cm from things that can suddenly pop out and strike the plane.

Re:Emergencies?

[RoccamOccam]

Professor Farnsworth address this issue: https://www.youtube.com/watch?...

Re:Emergencies?

[Stickasylum]

That's not right. If you drilled a bunch of holes in the table, the paper would indeed fly up and you wouldn't break the ruler. The airspace between the paper and table is clearly an integral component of the phenomenon.

Re:Emergencies?

[Dog-Cow]

There are literally thousands of things which are now practical to build, but weren't at one time. Like the computer I am typing this comment on. Even as little as 10 years ago, there was no practical way to build it to the same specs, even as a one-off prototype.

Your complete lack of logic paints as you a fucked-up moron who deserves to experience extreme decompression -- first hand.

Re:Emergencies?

[Rei]

Ed: that should read "total loss one entire support".

Re:Emergencies?

[Rei]

You know what also has the energy of 45 tonnes of TNT? A moderate sized (~10t) pine tree. Comparing total energies in something to TNT is only relevant if you're looking at the concentrated and instantaneous release of energy, neither of which are applicable to a vacuum pipeline. Even the supersonic shocks take several minutes to reach each end, let alone total pressure equalization, which even if there was no wall drag at doesn't proceed faster than the speed of sound.

The problem is what happens when a train car traveling 700 mph hits a section of tube damaged by a localized implosion.

Life isn't a cartoon. Inch-thick steel vacuum pipelines with periodic reinforcing rings don't peel like a banana just because you make a hole in them.

, and the following train cars hit it at 700 mph.

Because they totally didn't think to include sensors and emergency braking in the design document, right?

Yeah, you might want to actually read the design document of the thing you're arguing against before you complain about it.

At the fastest launch rate the vehicles are spaced 30 seconds apart (usually several times longer). At the highest achieved speed of 340 m/s (not average speed),
deceleration equates to a requirement of 11,3m/s, or only 1,15g. Deceleration inside a steel tube is incredibly simple.

Re:Emergencies?

[fedos]

How do you get to the emergency exits after you've been crushed to death?

Re:Emergencies?

[Gavagai80]

However the biggest problem I see from my chair is keeping a relatively fragile tube stretching hundreds of kilometers airtight, undamaged and secure from pissed farmers, drunk idiots, gun fans, vandals and other similar factors.

Is that problem different from, say, oil pipelines?

Re:Emergencies?

[rastos1]

I guess that the hyperloop tube is closer to inhabited areas. But apart from that, no, not that much. Just substitute spilled oil with spilled passengers.

Re:Emergencies?

[tehcyder]

How do you get to the emergency exits after you've been crushed to death?

Very, very slowly.

Re:Emergencies?

[Rei]

If you're invoking fantasy scenarios where shock waves move at mach 80 and instantly repressurize a tube hundreds of kilometers long because the inch-thick steel tube with reinforcement bands peeled like a banana when someone made a hole in it, like some sort of Bugs Bunny cartoon .... then I'd say that the best way to get out would be to paint a door on the side of the tube and open it.

Re:Emergencies?

[JustAnotherOldGuy]

Please don't cry when your hyperloop wet-dream never materializes.

Re:Emergencies?

[angel'o'sphere]

We talk about a vacuum tube, where an air thight cabine under pressure of 1 atmosphere is traveling ... on mag level rail. There is nothing it can crash into. To have something to crash into, it either needs to hop from its rail, or someone needs to quickly open the tube, place an obstacle, clsoe the tube again and pump out the air again ... good luck with that.

A catastrophe inside of a vacuum tube on a rail can only happen if the rail breaks, so: there are no forces compareable with an air plane crash.

Re:Emergencies?

[JustAnotherOldGuy]

We talk about a vacuum tube, where an air thight cabine under pressure of 1 atmosphere is traveling ... on mag level rail. There is nothing it can crash into.

Unless something comes loose inside, or the rail develops a fault, or one of the cars drops a part, or the tube becomes deformed, or some asshole shoots the tube with a deer rifle, or a car is driven into it, or some crazy fuck sets an explosive charge under part of it, or there's an earthquake*, etc etc.

Yes, clearly it would be impossible for anything to ever go wrong. Accidents never happen, which is why there's no word for "accident".

-

*Earthquakes never happen in California, by the way. Except the the magnitude-5.2 earthquake that rocked Southern California early last Friday. But other than that one, they never ever happen.

thunderf00t says bs!

[Anonymous Coward]

Thunderf00t does debunk video of hyperloop

Re:thunderf00t says bs!

[JustAnotherOldGuy]

Thunderf00t does debunk video of hyperloop

And he did a good job if it, too. Even if just one or two of the points he raises are valid, the whole thing becomes an insurmountable engineering nightmare.

The hyperloop is more pie-in-the-sky bullshit from Elon Musk. Don't get me wrong- he has some very workable ideas, but the hyperloop ain't one of 'em.

Re:thunderf00t says bs!

[amiga3D]

Like most things, it's bullshit until it works. Then it's genius.

Re:thunderf00t says bs!

[JustAnotherOldGuy]

Like most things, it's bullshit until it works. Then it's genius.

Yes, the key words being "until it works", which in this case will never happen.

Sure, that claim has been made before (manned flight, space travel, etc etc). But none of those things combined insurmountable engineering roadblocks with financial impracticability. The hyperloop has both, and if you can't see that then I'm sorry for your lack of perspective.

If I'm wrong, then I'm wrong...but I don't think that's the problem here. Anyone who's looked closely at the issues with the hyperloop has to come to the sobering conclusion that it's a really cool idea in theory, but one that will never come to fruition.

Re: thunderf00t says bs!

[Anonymous Coward]

There's this cult of personality around Musk in the geek community and I think he's starting to believe the hype is based on reality.

Re:thunderf00t says bs!

[JustAnotherOldGuy]

Problem is, a lot of you tech guys, especially programmers, think ALL ideas are genius, regardless of reality, engineering, or physics.

Well said.

Most programmers have little or no practical experience in hardware or physics, and so *any* cool-sounding idea seems possible to them. Those of us who do have a background in hardware and physics look at this stuff and laugh at the childish naivete of the people who are cheering it on.

I can hardly blame the programmers- most of them have seen amazing things happen in their lifetime (computers, cell phones, gene editing, the internet, etc etc) so it's understandable that they think that anything that can be thought up can be done...but again, their lack of real-world experience makes them prone to ignoring the practicalities of the actual engineering. To them everything is just a problem of managing the data by coding a clever function or two. In software you can do just about anything, there are almost no limits....but that's just not the case in the real world.

Re:thunderf00t says bs!

[religionofpeas]

Anyone who's looked closely at the issues with the hyperloop has to come to the sobering conclusion that it's a really cool idea in theory, but one that will never come to fruition.

Anyone...except the guys building it.

Re:thunderf00t says bs!

[Anonymous Coward]

LOL, that was just a sad video. People should not pretend to be smart when they clearly are not.

Re:thunderf00t says bs!

[JustAnotherOldGuy]

Anyone...except the guys building it.

They haven't managed to do jack shit yet, even with their toy track, and they never will.

Re:thunderf00t says bs!

[nukenerd]

"But the fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses. They laughed at Columbus, they laughed at Fulton, they laughed at the Wright Brothers. But they also laughed at Bozo the Clown." Carl Sagan

Help me here, which one(s) are/are not the genius?

Re:thunderf00t says bs!

[religionofpeas]

But they have looked closely at the issues, and have come to a different conclusion, so your statement is false.

Re:thunderf00t says bs!

[JustAnotherOldGuy]

The make of that video, Shane Killian, is way out of his depth. Way, way, waaaaaaaay out.

If I had time I'd do a video debunking his debunking and show what a dopester he is.

Re:thunderf00t says bs!

[Hognoxious]

I call it the rloop because I cut out all the hype.

Re:thunderf00t says bs!

[angel'o'sphere]

Those of us who do have a background in hardware and physics look at this stuff ...
You certainly have no such background.

Re:thunderf00t says bs!

[nukenerd]

Like most things, it's bullshit until it works. Then it's genius.

Yes, the key words being "until it works", which in this case will never happen.

It will happen. There will be a hyperloop between a couple of places, as a sheik's toy in Dubai, or even LA to Las Vegas as a tourist attraction, but that will be it. It will be far too expensive for wider use, and for safety reasons run at far lower speeds than Musk talks about, even if there are occasional faster publicity runs by technicians.

Re:thunderf00t says bs!

[nukenerd]

The idea of a vacuum being used is not new. Go google 'Brunel's Atmospheric Railway'. .... The Hyperloop is a very diffferent concept.

Then why bring it up? Brunel's railway used a vacuum tube between the rails for propulsion. The Hyperloop uses a vacuum tube around the whole train and track for air resisance reduction. Nothing whatever to do with each other.

Re:thunderf00t says bs!

[GuB-42]

Like most things, it's bullshit until it works. Then it's genius.

I suspect it will be bullshit for a very long time then. And by the time it becomes genius, if it does, the implementation will probably look nothing like the Hyperloop. If the only thing we keep from the Hyperloop is the idea of running trains in a vacuum, then it will just appear as one of the many attempt we made during the last 100 years.

Re:thunderf00t says bs!

[JustAnotherOldGuy]

Those of us who do have a background in hardware and physics look at this stuff ...
You certainly have no such background.

Au contraire, little one. I've probably forgotten more than you'll ever learn.

Re:thunderf00t says bs!

[JustAnotherOldGuy]

Germany and more importantly Switzerland has working prototypes since over 30 years.

If they've had working prototypes for that long then why isn't in operation anywhere? Because it's impractical bullshit, that's why.

Frankly, something that's been in the prototype stage for 30 years is more properly termed a "laboratory oddity".

Re:thunderf00t says bs!

[s.petry]

So where exactly are these massive 30 year projects in Switzerland and Germany? Are you attempting to claim that the LHC is a "hyperloop" now capable of human transport? That is the largest single vacuum system in the world, second only to Hyperloop's first test which was a tiny length of track, about 1/1000th of what would be needed to travel from LA to SF and lacked the diameter to move a human laying down.

Before you accuse others of posting bullshit, first prove that the laws of energy conservation are false. Then provide your citations for these 30 year programs from Germany and Switzerland, because I call bullshit on you. There are Maglev trains, but there are no massive lines of them being tested in massive vacuum chambers.

Re:thunderf00t says bs!

[JustAnotherOldGuy]

But they have looked closely at the issues, and have come to a different conclusion, so your statement is false.

We'll see. Or rather, we won't. :)

It'll never be built or used on any substantial scale for passenger transport, period. Not even for runs of short distances.

This is not a new idea, it's been tried before and it's always been abandoned as ridiculously impractical. And it will be this time too.

Re:thunderf00t says bs!

[igny]

thunderf00t's arguments reminded me of early arguments why it would not be possible for a steam engine locomotive to pull a train of cars. Locomotive's wheels would just slip and spin, they said...

Re: thunderf00t says bs!

[vtcodger]

I'm sure Elon will you that he can build a hyperloop system that'll be safer, cheaper, and much faster than California's hypothetical high speed rail system. It'd likely be faster. And maybe as safe. Cheaper? I'm guessing not, but who the hell knows?

Re:thunderf00t says bs!

[vtcodger]

"They laughed at Columbus"

And rightly so, the circumference of the Earth had been known since Eratosthenes computed it in 240 BC. If America hadn't gotten in the way, Columbus journey to the orient would almost certainly have been a dismal failure.

Re:thunderf00t says bs!

[s.petry]

All I can say is "Thank God people like you don't run anything important.". Science deniers claiming that the Laws of Energy Conservation don't apply to this project are simply ignorant fools. GP didn't need to rebut bullshit, the Thunderf00t Videos (yes, that is plural. As in more than one) lay\ out all of the scientific principles for you. You simply pretend they don't exist.

Re:thunderf00t says bs!

[Rei]

Problem is, a lot of you tech guys, especially programmers, think ALL ideas are genius, regardless of reality, engineering, or physics.

To be explicit in this case on who is who:

Hyperloop Alpha was created by engineers, going so far as to include FEM runs.
"Thunderf00t" is a biochemist with no background in engineering whatsoever.

Re:thunderf00t says bs!

[Rei]

The Hyperloop is a very diffferent concept. Many SF stories and movies use this concept.

Name a single sci-fi book that used a system built around air bearings in a partially evacuated tube, with compressors to prevent the buildup of air in front of them and boost the air bearings.

Literally everything about the design except for the presence of a tube is different between Hyperloop and a vactrain.

Re:thunderf00t says bs!

[amiga3D]

Maybe you've forgotten a little too much.

Re:thunderf00t says bs!

[JustAnotherOldGuy]

Maybe you've forgotten a little too much.

I really can't recall if I have or not.

Re:thunderf00t says bs!

[JustAnotherOldGuy]

thunderf00t's arguments reminded me of early arguments why it would not be possible for a steam engine locomotive to pull a train of cars. Locomotive's wheels would just slip and spin, they said...

[citation needed]

Re:thunderf00t says bs!

[amiga3D]

lol..... good comeback.

Re:thunderf00t says bs!

[angel'o'sphere]

What has teh tpoc to do with laws of energy conservation?

For prototypes you can google your self, rofl. I would start with ETH Zurich and/or Ruhr-UniversitÃt Bochum ...

Sigh ...

Re:thunderf00t says bs!

[angel'o'sphere]

If they've had working prototypes for that long then why isn't in operation anywhere?
Germany does not need them, we sold basically the "TransRapid" to the Chinese (a mag lev train outside of a vacuum tube).
In Switzerland the plan was, and still is, to bore tunnels under the mountains. So far no one really decided to build something like this. But I would not be surprised when the basic industris for cabines and other parts are developed that Switzerland will again look into such plans.

Re:thunderf00t says bs!

[JustAnotherOldGuy]

If they've had working prototypes for that long then why isn't in operation anywhere?
Germany does not need them, we sold basically the "TransRapid" to the Chinese (a mag lev train outside of a vacuum tube).
In Switzerland the plan was, and still is, to bore tunnels under the mountains. So far no one really decided to build something like this.

So in other words, you just made my point for me- no one is using them anywhere, even after decades of fucking around with the idea. Gee, why is that? Not enough hyperloop nutters to lobby the government? Or is it just an impractical idea with no raison d'être?

We're far, far more likely to go to the Moon again than build a working hyperloop. Fantasize all you like, but it's not going to happen.

Re:thunderf00t says bs!

[angel'o'sphere]

Not enough hyperloop nutters to lobby the government?
No, Switzerland is bottom line to small to make it a reasonable investment.
Germany already has high speeed trains and a "hyperloop" would only be roughly twice as fast.
On the other hand: the USA has no high speed train/rail network, hence: it is a very good idea, and you are jsut an anti tech moron.

We're far, far more likely to go to the Moon again than build a working hyperloop. Fantasize all you like, but it's not going to happen. You seem not to grasp how simple the construction of a hyperloop is, rofl.

Re:thunderf00t says bs!

[JustAnotherOldGuy]

You seem not to grasp how simple the construction of a hyperloop is, rofl.

Well then why don't you just pop down there in your flying car and give us all a progress report? Better yet, use your personal jetpack. Both of those things are way easier to build than a hyperloop and a hell of a lot cheaper too.

for(;;)

[peetm]

And breathe!

PROGRESS!!!

[JustAnotherOldGuy]

"Hyperloop One has released the first photographs of its "proof of concept" test track "

Wow, now they have photos, it MUST be real! Who could doubt the viability of this thing now??

Re:PROGRESS!!!

[Oswald McWeany]

Part of the scientific method is testing to see if something works.

Obviously they have built something because there is now a test track. The next step is to see- does it work or does it fail. I don't think many people on Slashdot are knowledgeable enough to bet their mortgage on whether hyperloop will ever take off or not.

Personally, I'm glad someone is trying, if it works, it could be an interesting transportation method with novelty value, even if not as a major gridlock solution. If it fails, at least we know now.

I think that someone is trying something new and that is good- work or fail. (and he obviously isn't going to throw money away unless he has scientific advisors claiming they can pull it off). If this fails, something else might be discovered in the process. Try nothing new and nothing new is learnt.

No windows?

[Anonymous Coward]

Definitely sucks. May as well bury the damn thing.

Aircraft, car, train do transport mostly

[Max_W]

themselves. And in this system the chassis is the tube, and it is not moving.

As for emergencies, let us first have an emergency at the test site and see what could be done.

I think this experimental site would be in human history something like Johannes Gutenberg's printing shop of 1450, or Tim Berners-Lee discovery of hyperlink in 1989.

When a man flew first time in space in 1961, the next day there was only a tiny article in a central newspaper. As saying goes - destiny knocks on the door quietly.

Re:Aircraft, car, train do transport mostly

[tehcyder]

When a man flew first time in space in 1961, the next day there was only a tiny article in a central newspaper.

What? Yuri Gagarin was pretty much the most famous man on the planet after his flight.

the "loop" in Hyperloop

[supernova87a]

Have they successfully built / connected any curved sections yet? I would imagine that's an important proof of concept at the technical level... just to be able to get the components sourced with the required tolerances and joined seamlessly....

Re:the "loop" in Hyperloop

[nukenerd]

Have they successfully built / connected any curved sections yet? I would imagine that's an important proof of concept at the technical level.

Don't worry. At the speeds they want there cannot be anything like you would recognise as a curve or the passengers' eyeballs would start popping out. Even on modern conventional railways they avoid curves less than 1-2 km radius. "Curves" on the hyperloop could probable be made just by slight shimming of the joints between tube sections.

BTW, I love these Hyperloop stories. They reveal such a load of public misconceptions (I mean generally, I'm not referring to the parent).

Re:the "loop" in Hyperloop

[radarskiy]

Conventional steel-wheel-on-rail trains are limited in their radial acceleration by the minute amounts of superelevation possible, while a hyperloop train is free to bank up to 90 degrees.

In addition, since a hyperloop will not share infrastructure will conventional trains and will need independent right-of-way anyway, it doesn't have to fit into existing curves. OTOH, it isn't going to fit into medians of interstate highways any more than conventional trains.

Really, what's going to be the limiting factor is not any technology, it is right-of-way acquisition.

Re:the "loop" in Hyperloop

[Rei]

Conventional trains can fit into medians just fine if they're elevated. But peak loadings on conventional trains are about an order of magnitude higher than Hyperloop because of the much larger vehicles, which makes for around an order of magnitude higher cost to elevate it. So conventional trains generally try to minimize the use of viaducts.

Hyperloop does not in any way, shape or form call for "fitting into existing curves" or "banking up to 90 degrees", which you would damn well know if you had actually read the design document, which lays out every single curve's turning radius and how much private land acquisition would be needed.

Re:the "loop" in Hyperloop

[radarskiy]

'Conventional trains can fit into medians just fine'

Interstate highway radii are typically designed for a speed of 70 miles per hour. Even in the US we have trains that go faster than that.

'Hyperloop does not in any way, shape or form call for "fitting into existing curves"'

That may be why I did not say it would fit into existing curves. I will thank you to stop implying that I did.

As for banking, since the tubes have circular cross-section it would be quite a chore to stop the capsules from banking. The problem with superelevating rails is that it's a fixed elevation so it has to handle all speeds down to 0. For a capsule riding the interior of a tube, it will ride up and down the curve as the centripetal force increases or decreases.

Huh...

[XSportSeeker]

We're still reporting on this scam as if it was a real thing? Wow...
Monorail... monorail... MONORAILLLLL

Re:Huh...

[enrique556]

Yes. I'm a bit surprised I had to scroll down so far to find the word "scam" in the comments. Elon Musk is a genius but somehow his brain did a big smelly fart and he's still not owning up to it. There's plenty of videos on youtube and commentary on the web debunking the remote possibility that the proponents of this shit actually believe it will work. LIke so many pointless charities with the word "children" in their name, this is purely an exercise in soaking up funding in admin costs, giving these scam artists 10-20 years of cushy jobs with BMW x-5 company cars and french champagne for lunch.
Elon Musk really should do the right thing and call these guys out, and denounce this idea outright. Alternatively, hook these people up to lie detectors and ask them if they believe it'll ever work.

Science is wrong?

[s.petry]

If you wish to make such an asinine claim back it up with science. I gave a link to a guy who did all of the science and demonstrates the power required to create a vacuum.. Mythbusters did a similar episode again showing the _SCIENCE_ behind the energy required to create a vacuum.

Will you next attempt to claim that conversation of energy is wrong?

doubt the viability

[hackwrench]

Doubting the viability is one thing, but what people have been saying here is outright rejection.

Re:doubt the viability

[JustAnotherOldGuy]

Doubting the viability is one thing, but what people have been saying here is outright rejection.

Probably because it's just plain bullshit and some people aren't afraid to say so.

Re:doubt the viability

[hackwrench]

Except if it is nonsense, they are doing a lousy job of demonstrating it is the case.

Re:doubt the viability

[Sycraft-fu]

No, people have demonstrated why it is BS quite well: It has major flaws, none of which they have an answer to. It isn't like this idea hasn't been thought of before, it has, but it never happened due to the issues. Until they have an answer to "How do you deal with a failure?" it is a non-starter. With anything you have to ask what are the consequences of a failure, what can cause the failure, and what do you do in the case of a failure before you can deploy it.

That's why airplanes have shit like fully redundant systems, a rigorous maintenance schedule, and trained operators. Because a failure is a big deal. It can not only kill everyone on board, but others as well. Hence there are backups to the backups, and plans for dealing with shit so that when something happens you have a situation where the pilot lands it in the Hudson, rather than smashing in to a neighborhood. This is also why there's nothing like a "flying car". You can make small planes, and they are something that could be affordable to the wealthy, however regulations will require them to be treated like aircraft, because the problems if they fail are so much greater than if a car fails.

Given that a dent in the tubing could cause a catastrophic failure where the tube crushes and a pressure wave is formed that turns the passenger container in to a very large, very fast projectile, they have to have an answer to "How do you deal with that?" before there's any reason to look at going further.

Re:doubt the viability

[Rei]

Yep. Solar power. Wind power. Batteries. Mainstream hybrid cars, and then mainstream electric cars. Private rocket companies making deliveries to orbit. Slashdot comments sections have always been bastions of the "that can never happen!" crowd. Which is really strange for a tech-focused site.

Re:doubt the viability

[Rei]

No, the first thing you have to do is read the damned design document, which is something that almost none of the people who rail against Hyperloop have ever taken the time to do. Which is transparently obvious in their comments, full of rants about "they never considered this serious issue which I, Smart Person, thought of!" - when in reality said issue takes up a major portion of the document.

Re:doubt the viability

[tehcyder]

Yep. Solar power. Wind power. Batteries. Mainstream hybrid cars, and then mainstream electric cars. Private rocket companies making deliveries to orbit. Slashdot comments sections have always been bastions of the "that can never happen!" crowd. Which is really strange for a tech-focused site.

I seriously doubt that anyone on slashdot has said that batteries wouldn't ever happen...

Re:doubt the viability

[Rei]

Yeah, I totally believe you that you've actually read it. Totally. This is my believing-you face.

Re:doubt the viability

[Rei]

It's been a constant stream of "batteries haven't advanced and won't advance" over the past decade, a period of time when they've undergone huge advances.

Re:doubt the viability

[Gr8Apes]

I think what the complaint has been, at least from my perspective, is that battery storage hasn't advanced in leaps, only in small evolutionary type advances, since Lithium batteries came on the scene. It's been a long long time since anything revolutionary in batteries has significantly affected recharge time, lengthened lifespans, or increased power density. There's several quite exciting developments in R&D currently, mostly for medium plus storage as in house sized. That is a huge thing if you're wanting to go renewables and/or be at least somewhat off-grid.

Re:doubt the viability

[Rei]

Are you kidding? Lithium-ion batteries used to all take several hours to charge. Now some types can charge in 10 minutes or less. Gravimetric energy density has quadrupled since li-ions first hit the market. Volumetric has sextupled. Power density, 1 1/2 orders of magnitude. It used to be said that all li-ions would fundamentally only last ~2 years whether in use or not. Now we have huge li-ion battery packs being warrantied for 8-10 years.

The problem is not batteries, it's people's lack of paying attention to the changes around them.

Re:doubt the viability

[Gr8Apes]

Are you kidding? Lithium-ion batteries used to all take several hours to charge. Now some types can charge in 10 minutes or less.

Along with pyrotechnic shows sometimes gone wrong. Seriously, a multi amp hour battery still takes hours to charge safely.

Gravimetric energy density has quadrupled since li-ions first hit the market. Volumetric has sextupled.

Yay, so I now have a double or triple run time for a given battery after 25 years. That's incremental, not orders of magnitude.

For the serious stretch, I'm envisioning a battery pack that gets hit by lightning and holds a multi kilo amp hour charge for months. Near term, a phone that charges in a few minutes and runs for a week would be a major step up. We are no where near that kind of battery system, and nothing I know of will be forthcoming.

Re:doubt the viability

[Rei]

Along with pyrotechnic shows sometimes gone wrong. Seriously, a multi amp hour battery still takes hours to charge safely.

Nonsense. Tesla uses ordinary 18650s and charges them in 40 minutes. Batteries that stress power density over energy density can charge in under 10 minute charges. Trust me, I've used them. They've been on the market for years.

Yay, so I now have a double or triple run time for a given battery after 25 years. That's incremental, not orders of magnitude.

Most technological fields would kill for advancements on the order of 4x, 6x, or ~20x in ~25 years. Do you think - say, picking a random example - that tensile strengths have advanced anywhere near that much? How about rocket propellent performance? Internal combustion engine efficiencies? Car tire rolling resistance improvements? Seriously, just because computers have advanced by Moore's Law doesn't mean that anything even close to that is normal. The rate of battery improvements has been very rapid by the standards of most technologies.

Re:doubt the viability

[Gr8Apes]

Along with pyrotechnic shows sometimes gone wrong. Seriously, a multi amp hour battery still takes hours to charge safely.

Nonsense. Tesla uses ordinary 18650s and charges them in 40 minutes. Batteries that stress power density over energy density can charge in under 10 minute charges. Trust me, I've used them. They've been on the market for years.

So, if those miracle 10 minute chargeable batteries are so common, why all the pyrotechnics with phones, tablets, laptops, hoverboards.... The list just doesn't end. Everything that has used "fast charge" batteries has wound up on a nice smoking youtube video. Perhaps they're not as common or as viable as you make out?

Yay, so I now have a double or triple run time for a given battery after 25 years. That's incremental, not orders of magnitude.

Most technological fields would kill for advancements on the order of 4x, 6x, or ~20x in ~25 years.

Improvements in orders of magnitudes: CPUs - 1000s. Memory - 1000s. Controller chips - 1000s. Batteries - 0.3.

Do you think - say, picking a random example - that tensile strengths have advanced anywhere near that much? How about rocket propellent performance? Internal combustion engine efficiencies? Car tire rolling resistance improvements? Seriously, just because computers have advanced by Moore's Law doesn't mean that anything even close to that is normal. The rate of battery improvements has been very rapid by the standards of most technologies.

Rocket propellant efficiency was pretty much completed around the early 60s. Before that - sure. Tensile strengths? To what are you referring? Of a material? No. That's a physical property. Of manufactured structures for a given purpose? Absolutely doubled at least since the 80s (not quite 25 years, but you're talking about a field that's been around for centuries). Internal combustion engines have certainly improved, but the days of large improvements were very early on, and the limits were physical, you can't get more energy out than you put in. Were there orders of improvements in removing losses? Depends on what window in time you pick and how you define the improvement. Car tires have improved in many ways over the last 150 years, however rolling resistance is a tough one - how much comfort are you willing to give up? Sure, I can make several orders of improvement in rolling resistance, but your teeth will likely not agree. Beryllium tires wouldn't be too comfortable, and likely would not last very long either.

But, with batteries, their purpose is to store electrical power, and release. For instance, capacitors can rapidly store and release power, far far more efficiently than any battery. They're just not energy dense enough to replace batteries, plus there are some other challenges. The point here is that a battery is still like a 1800s wood burning steam engine compared to the charging rate of a battery, and like a large tank of gasoline for storage. It will eventually break out, just like fusion energy will eventually happen.

Re:doubt the viability

[Rei]

So, if those miracle 10 minute chargeable batteries are so common

Not particularly common, but available. Most manufacturers prefer energy density to charge time. You get ~2/3rds the energy density on fast charging packs that you get on the highest density 18650s.

why all the pyrotechnics with phones, tablets, laptops

If you're talking about the Samsung battery fires, it's because they left no room in their phones for thermal expansion.

hoverboards

NEWSFLASH, cheap Chinese junk produced at unregulated factories and without any sort of safety inspection undergoes an electrical fire. Details at 11!

CNET's summary of the hoverboard fires sums up the reasons as:

So far, some reports have blamed the batteries, others the cables, but we don't know for sure. The UK divisions of retailers Amazon and Costco are specifically telling customers to destroy charging cables that have plugs that weren't built to UK safety standards. (Costco is providing replacement cables, while Amazon is offering full refunds.)

Another possible culprit is the cut-off switch, a safety feature that keeps an electronic device from overcharging, which the UK's National Trading Standards consumer protection agency says can often fail in these hoverboards. EcoReco's Sung suggested that to save costs, some hoverboard manufacturers might not even include a cut-off switch to begin with. That's clearly not the issue everywhere, though, as Mashable recently tore down a Swagway hoverboard that appeared to have a cut-off switch installed.

Yes, if you abuse batteries, you can make them burn. Wow, what a shock. I suppose it most also shock you to learn that if you abuse gasoline, it will also burn.

Everything that has used "fast charge" batteries has wound up on a nice smoking youtube video.

Not a single thing that you listed uses fast charge batteries.

Improvements in orders of magnitudes: CPUs - 1000s. Memory - 1000s. Controller chips - 1000s. Batteries - 0.3.

Right. Computing is the one thing that's advanced so dramatically. Your expectation that if a technology doesn't advance as fast as computing is absurd. Do you hold this standard to any other pieces of technology?

Rocket propellant efficiency was pretty much completed around the early 60s. Before that - sure.

No, there still are advances in propellant. But they're slow.

Tensile strengths? To what are you referring?

I'm referring to tensile strength. If you don't know what tensile strength is, you really need to learn some very, very basic physics. That's like saying "I don't know what mass is"

Of a material?

No, of a cat.(/snark) Of course of materials. Materials in all fields. Tensile strengths, compressive strengths, elastic moduli, etc have all improved with time. But like pretty much every technological field except computing, the rate of improvements are nothing at all like some endless, 1.5-year exponential growth rate.

Absolutely doubled at least since the 80s

"Doubled since the 80s" vs. "quadrupled / sextupled / 1,5 orders of magnitude increase (gravimetric energy density, volumetric energy density, power density) since 1991." Batteries win hands down.

Internal combustion engines have certainly improved, but the days of large improvements were very early on

There never was some brief period of large improvements; ICE improvements have been relatively steady throughout the years. And they continue improving. But like almost all technological fields, the rate of improvement is nothing like the rate of improvements in computing.

and

Re:doubt the viability

[Gr8Apes]

My apologies, somehow I missed your response....

So, if those miracle 10 minute chargeable batteries are so common

Not particularly common, but available. Most manufacturers prefer energy density to charge time. You get ~2/3rds the energy density on fast charging packs that you get on the highest density 18650s.

So, a little less energy density (30%?) I think for fast charge rates people would give up 30% runtime in a whole host of pluggable environments. So there must be some other reason we don't see reliable fast charge batteries in common applications. I'm thinking cost would be number one.

(Hoverboards) So far, some reports have blamed the batteries, others the cables, but we don't know for sure

Having owned one, and noting that there was a significant spark when attempting to plug it in, I'd say there was more wrong with those hoverboards than just batteries or chargers... quite possible the entire charging subcomponent consisted of a single wire from plug to battery. I had to plug it in a second time just to be sure I saw what I saw, and Amazon kindly refunded it immediately.

Not a single thing that you listed uses fast charge batteries.

And yet they all wound up in smoking piles of burnt electronics.

Right. Computing is the one thing that's advanced so dramatically. Your expectation that if a technology doesn't advance as fast as computing is absurd.

Of course it's absurd. We're also in the very very beginning of this tech. It's no different than the invention of the wheel to hyperloop, just compressed down into roughly 80 years. Just wait on the next technical revolution that may go even faster - bio-engineering.

Tensile strengths? To what are you referring?

I'm referring to tensile strength. If you don't know what tensile strength is, you really need to learn some very, very basic physics. That's like saying "I don't know what mass is"

Of course of materials. Materials in all fields. Tensile strengths, compressive strengths, elastic moduli, etc have all improved with time.

Totally incorrect - the tensile strength of an elemental material is a physical limit. Now, we may have not reached those limits in manufactured components, but the tensile strength is fixed. Now, for engineered materials, we certainly are improving, as well as creating new materials and new manufacturing techniques that bring us much closer to that physical maximum we seek on a macro scale.

But like pretty much every technological field except computing, the rate of improvements are nothing at all like some endless, 1.5-year exponential growth rate.

Computers, in case you haven't noticed, have fallen off the treadmill. The last 5 years at least have almost been standing still.

Batteries win hands down.

I guess I didn't recall how recently Lithium ion batteries came into existence. They certainly increased battery performance hugely, but within them they haven't really done more than double or triple over the last 20 years. (Note, that leaves the first 10 years where there were significant improvements)

ICEs still to this date are nowhere near their Carnot limit.

But they are near the physical limits of power losses due to friction and conduction losses until a frictionless, non-melting non-conducting material can be found, at least regarding efficiency. Now power out of a given sized engine? That can still go up quite a bit, at least from what we have in our day to day cars.

Today's tires are better in rolling resistance, comfort, safety, *and* cost than those of several decades ago. But again, the curve is nothing like that of computing.

Actually, tires have improved tremendously in many

wrong

[s.petry]

Thunderf00t correctly points out that a small weakness in the structure will cause a full atmosphere of pressure to attempt to breach the vacuum and the initial tearing will become massive in a tiny fraction of a second. The energy required to create a vacuum is quite large, and all of that energy will be inverted in a split second. If you don't believe Thunderf00t's science, try Mythbusters who did something similar with a rail car tanker.

There is an amazing amount of science denial in this thread, and worse.. up moderation of flat out science denial.

Re:wrong

[Rei]

"Thunderf00t" is a biochemist and the fact that people cite him as an expert in anything except biochemistry never ceases to amaze me.

Sorry, but inch thick steel does not peel back like a banana when you make a hole in it simply because there's a mere 1 ATM pressure differential. Nor does some supermassive shock travel like a brick wall hundreds of miles leading to instant repressurization. The behavior of rapidly progressing pressure waves is known as the shock tube problem. It's well studied physics, and with such a long length to diameter ratio and length to shock velocity ratio, "non-catastrophic" doesn't even begin to describe it. Yes, the wave travels very fast (several times faster than the speed of sound), but it does not carry a lot of force in these conditions, nor does it instantly raise the mass density to atmospheric over long distances, nor does "several times the speed of sound" equate to instant arrival a many hundreds of kilometers away. The same viscosity / wall friction limitations that apply to all tubes applies to Hyperloop.

As for the Mythbusters, DOT-111 railcars ,like the Mythbusters used, are not designed to hold a vacuum. They're not even designed to hold positive pressures; they're designed to hold unpressurized liquids. They're given a small (7 bar) requirement to meet in new condition, but that's it. There is nothing in their design that is supposed to prevent pressure-related collapse when damaged. And it still took about half a second second to collapse across such a short length (the length of a tanker car).

Nobody in their right mind would ever engineer a vacuum pipeline that can catastrophically collapse along its length. It is in no way, shape or form some sort of fundamental property of vacuum lines, and only a person who has never worked in engineering would think so.

If "Thunderf00t" (Phil Mason) says something about biochemistry, listen to him. If he starts ranting about fields that he has no understanding of, close the window.

Re:wrong

[dpidcoe]

If you don't believe Thunderf00t's science, try Mythbusters who did something similar with a rail car tanker.

If you're going to cite mythbusters, might I point you to the other test they ran in which they poked a hole in the side of a pressurized aircraft body and nothing much happened? No metal peeled back, no explosive decompression, just a fast air leak until the pressure equalized. It's been a while since I saw that episode, but iirc they eventually had to put explosives on it to actually make the sudden change in pressure actually do anything catastrophic.

Yet another science denier

[s.petry]

How much energy does it take to create that vacuum under 1 atmosphere? Are you attempting to claim that the laws of energy conservation don't exist when it's a rich guys pet project?

Re:Yet another science denier

[dpidcoe]

How much energy does it take to create that vacuum under 1 atmosphere? Are you attempting to claim that the laws of energy conservation don't exist when it's a rich guys pet project?

You keep saying this, but I don't think you understand the difference between a sudden release of energy in the space of a few microseconds and the gradual release of energy over the course of multiple seconds. Re-pressurizing a long tube from one end can't happen instantly, so it will most definitely not be the same as releasing whatever amount of energy you think is stored in 1atm of pressure differential all at once.

Re:Yet another science denier

[angel'o'sphere]

Depends on the amount of air to pump ;D I guess you can google that. Or get fancy and try WolframAlpha ...

Re:Yet another science denier

[s.petry]

Creating a vacuum is not just an issue of pumping air. Perhaps your point was to emphasize your ignorance on the subject, because your comment about the system only being subject to 1 atmosphere of pressure was not enough...

Re:Yet another science denier

[angel'o'sphere]

Of course it is ...
The rest are close to trivial engineering problems.
There is no difference to creating an empty air less tube, or having a submarine dive mere ten meters deep.
Exact the same pressure difference.

Good grief

[s.petry]

How much energy does it take to create the vacuum? That is what the chamber is storing, unless you somehow believe that energy conservation does not exist. It is not just the downward pressure of the atmosphere, as a basic physics class can teach you.

To argue your point you must completely deny basic physics principles, so how does the Hyperloop do this exactly? If you want to state that well established principles of physics are wrong, I demand you provide proof.

It ever ceases to amaze me people who don't check

[Sycraft-fu]

Yes, vacuums DO exert a massive amount of pressure, or rather our atmosphere does and because there's no counter-balance in a vacuum that pressure is fully felt. The numbers are easy to get: about 14.7 pounds per square inch at sea level. That means about 15 pounds of force for every square inch of material, which is not a large area. You can throw a little math at something to figure out the total force a given area takes.

Also it turns out vacuum pressure is something that companies have to worry about, so they've tested it and posted demonstrations online. Here's one of a company subjecting one of their tanks to a vacuum and it failing in a spectacular fashion:

https://www.youtube.com/watch?...

This isn't Hollywood, this is a company that makes tankers for transport.

Mythbusters (which I'm sure you'll deride as being Hollywood) has a great episode where they try it with a tougher tanker and it dues survive under effectively full vacuum... until they drop something on it and dent it, at which point it fails spectacularly.

As a related thing to forces from a vacuum (or rather the sudden failure) have a look at ping pong ball cannons. You evacuate a tube with a ball in it, and then suddenly open up the end. The pressure wave can drive the ball to extremely high speeds:

http://www.instructables.com/i...

Cool but will teh economics work?

[joe_frisch]

Its a neat idea, even if it is a very watered down version of the 60's vacuum train concept that ran at near orbital speed. https://en.wikipedia.org/wiki/...

No fundamental physics issues, the big question is economics. The cars are pretty small and at those speeds you need a lot of spacing between trains. Curves need to be large radius and if track switching is even possible, the switches need to be very large. Its not clear that its less expensive than 350km/h high speed rail - which itself is often not cost effective.

The higher speed than high speed rail is nice for long trips (>150KM). but otherwise the boarding and accelerate /decelerate times will hide most of the difference. It will need airport like security since a relatively small bomb would kill a lot of people - sort of like an airliner, so it may be slower to board than high speed rail.

Not crazy but there isn't an obvious niche where it is cost effective (similar problems for maglev).

Re:Cool but will teh economics work?

[Oswald McWeany]

I suspect it will only be rich people who can afford to use the hyperloop if they get it working- at least for the foreseeable future. That's OK though. Who knows what the expertise in making these will lead to. Space exploration? Underwater habitats? The skills needed to pull off hyperloop will serve other purposes and engineers that work on this project will found companies that enrich humanity in other ways too.

Re:Cool but will teh economics work?

[joe_frisch]

Maybe, but the wealthy are able to live close to their jobs. It looks pretty uncomfortable so it probably won't compete with bizjets.

It might have a niche.where its useful.

Re:Cool but will teh economics work?

[Oswald McWeany]

In many cities, the rich wouldn't want to live close to their jobs. You're right though, it does sound uncomfortable; it will be surprising if they pull this off to be a smooth ride. I'm sure they can "class up" the cramped interiors if the clientele so desire. It would be nice if they could make this for the masses.

The rich got cars first, rode aeroplanes first, they'll ride the hyperloop first. It will be interesting if cost come down so you and I could ride in our lifetime.

The Number of Maintenance (fill in blank)

[Neuronwelder]

Tell me who is going to pay for the maintenance of air leaks. Who is going to pay for the drainage of water that will seep in? Who is going to maintain condensation that forms when pressure is reduced. And there might be icing problems as well with this plan.

Appeal to authority

[s.petry]

Instead of claiming some magical appeal to authority where you dislike the science presented, how about getting some science of your own to discount it. Namely, for the dozenth time in this thread, why does Conservation of Energy not apply to the Hyperloop. Understanding of course the amount of energy required to bring a massive single structure to a near perfect vacuum.

As to your claim about rail cars, they do have to test for partial vacuums. The test is not invalid at all, you are simply refusing (as you did with Phil Mason) to review actual science.

Re:Appeal to authority

[Rei]

how about getting some science of your own to discount it.

If you want to learn about shock tubes (what is being described), start reading.

Namely, for the dozenth time in this thread

You have not replied to a single other post I've written.

why does Conservation of Energy not apply to the Hyperloop

It does. Why would you think otherwise?

. Understanding of course the amount of energy required to bring a massive single structure to a near perfect vacuum.

First off, read the damn document before debating it online. The fact that you don't know that Hyperloop is distinctly not a hard vacuum, and that more to the point would not work in "near perfect vacuum" - one of the most basic aspects of the design - points out that you have no business whatsoever pontificating about the topic.

Secondly, evacuating 2.2m cubic meters at sea level takes a minimum of 223 GJ. Operating on the pessimistic assumption that the tube has to be pressure normalized once annually and zero energy is recovered in the process, divided by six million passenger-trips per year, is 37kJ, or 10,3Wh (note: *not* kWh, just Wh), or about 0.05 cents at industrial rates.

Now, of course, you don't get the thermodynamic minimum. But you were explicitly talking about conservation of energy, so that's the number you were looking for. And if you want to be fair and factor in other energy losses, you also have to factor in that the assumption that you have to empty the tube annually (with zero energy recovery) is unfair on the pessimistic side.

And if you want to know what real-world maintenance level pumping to maintain vacuums is like, LHC requires 170kW for 9000m, or about 19W/m - which in the case of Hyperloop equates to 41,8MW. If this were applied to Hyperloop, that would be a per-passenger cost of 220MJ, or 61kWh, or $30 at industrial power rates. Except that LHC is a hard vacuum, which is orders of magnitude harder to maintain than a mild vacuum like Hyperloop; one of the primary design principles of Hyperloop was avoiding hard vacuum specifically for that reason. Hyperloop's vacuum level is four orders of magnitude higher density than the LHC's cryomagnet insulation volume (we won't even bother discussing the incredibly low beamline vacuum). A simple linear interpolation would suggest a Hyperloop maintenance power of 0.0019W/m, or 4180W, or a per-passenger consumption of 22kJ, aka 0.006kWh.

I'm sorry, let's back up, what was all this ranting you were doing about the conservation of energy?

As to your claim about rail cars, they do have to test for partial vacuums.

I don't know what forums you're used to where you can just make up things and have people believe you, but that doesn't fly here. Tank cars are only tested to a fixed positive pressure. Here's the procedure, spelled out in US law. Here's a table of the pressures for different types of tank cars. DOT-111 cars are for storing nonpressurized liquids, and are thus only tested to the minimum test pressure of 100 PSI, aka 6.9 bar. They are not designed to survive a vacuum (although they do if not heavily compromised - which in the Mythbusters

Re:Appeal to authority

[s.petry]

The point about the conservation of energy is that the SYSTEM will be storing _all_ of the energy required to create the vacuum. A weakness in the structure would be catastrophic.

The nickel you falsely claim completely ignores the fact that until we have teleportation of mass objects and people solved, the system must go through a new process of creating the vacuum constantly. You will not be able to maintain a vacuum over such a massive system, especially while cars and people have to move in and out of the system.

Now to your easiest to disprove lie. Tankers must undergo some testing for vacuums because a vacuum system is used to release stored materials. Further, the inversion of pressure in the chamber is inversely proportional to an increase in pressure from a Fluid Dynamics and Structural analysis perspective. A failure from a massive increase in pressure would be identical when a massive decrease. The only difference is the direction the deformation moves and the final result. Massive collapse or massive expansion (material tearing, etc..)

You don't seem to have even a basic grasp of structural dynamics, fluid dynamics, or basic physics. You have the appeal to authority down pat, and a whole lot of BS.

Re:Appeal to authority

[MobyDisk]

You don't seem to have even a basic grasp of structural dynamics, fluid dynamics, or basic physics.

Rei posted coherent statements about physics, links to scholarly articles, and provided measurements. So Rei does indeed seem to have a pretty good grasp on those things.

You have the appeal to authority down pat, and a whole lot of BS.

You are the one who appealed to the authority of "Thunderf00t." Rei has made no appeal to authority that I saw. If I missed it, please quote it for me to show what I missed.

Re:Appeal to authority

[Rei]

The point about the conservation of energy is that the SYSTEM will be storing _all_ of the energy required to create the vacuum.

Indeed, the system stores the energy equivalent of dozens of tonnes of TNT.
So does a good-sized pine tree.

How you got under the impression that shock waves move at the speed of light is beyond me. I mean, I can understand that you might have a cartoon view of physics where a hole means that inch-thick steel bananas out like Elmer Fudd's shotgun, or where air can flow through an object with a huge length/diameter ratio without any wall friction effects across its length, or that you might confuse the concept of a shock with the concept of pressure equalization, or things like that. But surely you're not so far out of touch with reality as to think that shocks move at or close to the speed of light. Or are you under the impression that "several times the speed of sound" means travelling hundreds of kilometers instantly?

The amount of energy per meter of tube from the vacuum is about the energy equivalent of 9 grams of gasoline.

Tankers must undergo some testing for vacuums because a vacuum system is used to release stored materials.

That would be quite the trick, given that all DOT-111 tank cars have a vacuum relief valve that prevents you from drawing a vacuum. It's generally set at -0.75 PSI (0.05 bar below ambient).

Again, why are you under the impression that you can just make stuff up and not be called on it? How did you even think that makes sense, that a rigid tank would be emptied via the creation of a vacuum within it? How well does that work in your everyday experience? Can you drink a soft drink from a glass bottle by just sucking it all out without letting air in?

You have this bizarre concept that dealing with vacuums is something that there's not extremely extensive experience with, extensively covered by ASME VIII. Do you have a clue how many vacuum distillation units there are in the world and how much oil moves through them every day? Ever seen the diameter on those things? And yes, they operate at Hyperloop pressures.

Re:Appeal to authority

[painandgreed]

Secondly, evacuating 2.2m cubic meters at sea level takes a minimum of 223 GJ. Operating on the pessimistic assumption that the tube has to be pressure normalized once annually and zero energy is recovered in the process, divided by six million passenger-trips per year, is 37kJ, or 10,3Wh (note: *not* kWh, just Wh), or about 0.05 cents at industrial rates.

Hrrrm. Remembering my time working with vacuum chambers and having to evacuating them, this offers some interesting opportunities. Having a long tube with a transport vehicle would basically turn the entire system into a large mechanical pump above a certain pressure. Transport vehicle creating some pressure ahead of it as it acts like a piston which could be vented off to to other pumps needed during operation. Unfortunately, it doesn't look like the pressures desired would be low enough to need anything exciting like a diffusion or ion pump.

Re:Appeal to authority

[s.petry]

More lies, and enough dealing with stupid people who use sock puppets and AC posts to back their bullshit.

Dozens of tons?

Nice low ball estimate. LHC requires about .2tons and is a very small fraction of the size Hyperloop has planned. You are probably looking at 100 tons when all is said and done.

How you got under the impression that shock waves move at the speed of light is beyond me.

You just made up a flat lie, I never insinuated that failures occur at the speed of light. I stated that the full structure must conserve the energy and that a failure would see the brunt of the force. You just made the dumbest argument I have ever seen. Here is a hint: Take a nice tight coiled spring held with a thin rope. Put the spring on the floor and put your head on the top of the spring and cut the rope. The rope didn't have to be heavy to hold the spring, but the bruising welt on your noggin should be a reminder that things don't have to move at the speed of light to be harmful.

As a hunch, you have never ever seen simulations of things like car crashes, or bullet impact, or anything else for that matter. There are ways to simulate how they work and you can watch the structure failures before they ever occur. Notice that there are no FEA simulations to show what happens during a failure even though _BASIC_PHYSICS describes it happening. Why no FEA if the Hyperloop is so sound?

Next, the one tanker car you mentioned is not the only tanker car that is on the rails. You are a dumbass to believe that gravity drain is the most cost effective way to empty a tanker. And yes, you continue to show you are a dumbass. You also can not dispute the structural analysis portion I pointed out, so simply play the bullshit "nuh uh" ostrich game.

I similarly never stated that dealing with vacuums was new. We have plenty of accidents with vacuums and plenty of experiments to demonstrate structural failures with vacuum chambers. YOU on the other hand pretend that science does not exist, and experience does not matter. If only you believe strongly enough you can make things happen right?

Do us all a favor and be the first to volunteer on the test track. Make sure you post your real name so I can submit you for a Darwin award.

Re:How many billions has CA wasted

[fedos]

All Elon Musk has done is demonstrate how impractical the idea is.