Author Topic: The Hyperloop: BUSTED  (Read 75321 times)

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Offline Maxlor

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Re: The Hyperloop: BUSTED
« Reply #75 on: July 28, 2016, 06:44:54 pm »
Second, why would the whole system have to be one open, connected tube? You could add a pressure lock every 1km that opens for cars and closes behind them, which would thus contain a catastrophe.

Now one fails to open:




>1000km/h into a wall sounds awesome!
Hehe yeah, that would be quite spectacular. So those locks better actually work :) And if they don't... well if you open them far enough in advance, the car can brake and stop before hitting it. Opening them about 6km ahead of a car should just about be enough.
 

Offline Maxlor

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Re: The Hyperloop: BUSTED
« Reply #76 on: July 28, 2016, 07:29:24 pm »
He's doing back of the envelop calcs to show how impractical and fragile the system is going to be.
You only need one of those showstoppers to be true to the entire project to be a guaranteed bust.
Nope, he's not. He's facepalming in a very elaborate way. If he has done back of the envelope calculations, he's certainly not showing them in the video. And yeah, I agree, one showstopper would be enough. But Thunderf00t hasn't demonstrated one. Personally, I think the likely showstopper is cost; if I were to try busting the hyperloop idea, I'd start there. Then again, this might become a prestige project that some government would be willing to throw unreasonable amounts of money at. It happens  :-//

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That implies that you think he's wrong and you have "obvious" solution to his argument.
Please present those obvious and less obvious solutions.
No, I think he's making a fallacious argument: he's saying that some problem is unsolveable because one suggested solution doesn't work. But to be convincing, he'd have to demonstrate that no feasible solution can exist.

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Shock absorbers are much smaller in diameter, not a good analogy.
And you need thousands of these large diameter seals to work perffectly 24/7 to keep this system working. It's a fundamentally stupid idea from a practical engineering standpoint, when you can eliminate all that problem with existing proven tech at half the speed (MagLev)
It wasn't meant as an analogy, but as an example. Maybe vacuum seals really won't scale up, but then again, they don't have to scale up far, we're only talking an order of magnitude here, which feels to me like something that's difficult but far from technically impossible to do. Maybe someone with a mechanical engineering background can elaborate? And Hyperloop claim that the seals don't have to work perfectly, again they say the assume that there will be leaks.

And well, calling something stupid with lots of handwaving towards various problems is stating an opinion, maybe even an educated one. But it's not really enough to be called busting an idea, imo.

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The argument is that it seems pretty stupid to even try to manage such a system.
Didn't hear that, maybe because I didn't read between the lines deep enough. But hey, why not run the numbers in a back-of-the-envelope kind of way and say something like, even if you use the best available seals which have reliability x, and you have very good technicians to replace them in y time, you'd still spend more than half a day every day replacing seals, which would mean downtime for the system... yadayada. But saying "6000 seals!!!", and adding some more rethorical exclamation marks instead of an explanation isn't a very convincing argument.

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The video segments showing those interior designers: what are they doing in the video, they're supposed to show that Hyperloop consists of idea people with little background in engineering?
Solar Roadways have engineers.
UBeam have some of the finest ultrasonic PhD's in the world.
Both of these ideas will never ever work.
My point was: How is showing that hyperloop employs designers too furthering the unfeasibility argument? Well, it doesn't. It's ridiculing hyperloop, which whether they deserve it or not does nothing as far as busting feasibility is concerned. So why even have that scene in there at all.

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It's technically possible if you throw money at it, but any practical engineer should be able to see all the big potential showstopper issues here. Unless you have a cool job at Hyperloop and then you have blinkers on, just like those at uBeam.
They are throwing quite a bit of money at it. Is it enough? Again, some back of the envelope calculations would come in handy, but someone would actually have to do them. Maybe it should be the guy that's trying to convince everyone else it couldn't possibly work.

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But one incident will take down the entire system and likely costs lives. It's an inherent fragile engineering system. In fact it's probably the most fragile system you could come up with. Good engineering does not base itself around an inherently fragile system.
Most fragile? I'd probably go with airplanes for that one. They're as safe as they are because of massive overengineering. And well, yes, incidents will affect the system and kill people, that's the nature of them. Train collisions unfortunately still happen too, they kill people, they cause blockages for days, yet people still use those.

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A door (and seals) that need to automatically open and close every 1km, at 1000kmh, do the math. This idea simply takes you further down the rabbit hole of impracticality.
You are trying to come up with a solution to fix an idea that is inherently flawed.
I have thought about that, and it doesn't seem so difficult to do? The doors themselves could move quite slowly, and open well in advance of a car. They'd have to move just fast enough to isolate two cars from one another, pressure-wise.

But really, my point is not about the hyperloop. My point is that if you claim BUSTED, you need to actually show BUSTED. And saying "Can't you see how ridiculous this is?" isn't showing anything. Doesn't have to be an airtight proof, but there have to be at least a couple of steps in that direction. And if you don't do that, I'll call it an unconvincing argument, regardless of whether I think that the claim has merit or not.
 

Offline mtdoc

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Re: The Hyperloop: BUSTED
« Reply #77 on: July 28, 2016, 08:14:49 pm »

But really, my point is not about the hyperloop. My point is that if you claim BUSTED, you need to actually show BUSTED. And saying "Can't you see how ridiculous this is?" isn't showing anything. Doesn't have to be an airtight proof, but there have to be at least a couple of steps in that direction. And if you don't do that, I'll call it an unconvincing argument, regardless of whether I think that the claim has merit or not.

I agree. My opinion of Thunderfoot went down a few notches after watching the videos. IMHO he's using the solar roadways comparison as click bait  - trying to garner views,  but his attempt at  " busting" the hyperloop concept is a fail.  It may or may not be viable but he has not proved it isn't - only pointed out some of the well known challenges while refuting some possible solutions to those.  With solar roadways - the problems are well known and well studied - and easily proved insurmountable with current PV technology.  Hyperloop is different - this is a new concept and most of the technology has yet to be developed. 

I agree that any LA to SF hyperloop is very unlikely to ever be built - but I suspect that is will more likely be due to cost and politics.
 
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Offline rs20

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Re: The Hyperloop: BUSTED
« Reply #78 on: July 28, 2016, 09:06:29 pm »
Now one fails to open:

Hmm, it's also fairly important that railroad switches don't fail. Congratulations for once again delivering an argument that "busts" existing railroads just as much as the hyperloop. Seriously, I'm not defending the practicality of the Hyperloop, much like Maxlor. But pithy remarks like this that don't actually bust anything are exactly the sort of polarizing rhetoric that makes the internet such an echo-chamber.

BUSTED means it isn't a practical solution.

The claims made by solar roadways can be demonstrated to be impossible on the back of an envelope. Not just impractical, but forbidden by the basic laws of physics. The story for batteriser is similar.

The hyperloop could be constructed, theoretically. It might be insanely dangerous. It might cost more money that the entire world has. It might be entirely pointless, and indeed massively impractical. But it is not outright impossible. In particular, I find "If X breaks, then you die" arguments utterly bizarre and unconvincing, because airplanes.

Now of course there's no point getting into a nomenclature debate here, you are free to define "BUSTED" however you choose, and to be absolutely clear I'm not claiming that anything you've said or referenced is incorrect. I just want to express that there is a distinct shade of grey here*, unlike the cases of Solar Roadways and Batteriser. The tfoot video, in my opinion, muddies and dilutes the "brand" that is "BUSTED".

* Which, as expressed above, the internet sucks at handling/representing -- although I think this means we have a responsibility not to contribute to this fact.
 
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Offline EEVblog

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Re: The Hyperloop: BUSTED
« Reply #79 on: July 29, 2016, 12:35:39 am »
Hyperloop is different - this is a new concept and most of the technology has yet to be developed. 

It's a concept that is nearly 100 year old.
 

Offline EEVblog

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Re: The Hyperloop: BUSTED
« Reply #80 on: July 29, 2016, 12:40:25 am »
Hmm, it's also fairly important that railroad switches don't fail. Congratulations for once again delivering an argument that "busts" existing railroads just as much as the hyperloop. Seriously, I'm not defending the practicality of the Hyperloop, much like Maxlor. But pithy remarks like this that don't actually bust anything are exactly the sort of polarizing rhetoric that makes the internet such an echo-chamber.

Do the math.
The doors have to open and close within seconds of a capsule arriving at the speed of sound.
And a breach in one section will likely blow out the seal and/or the surround and cascade that failure into the next section.
It's engineering folly.
It's only being worked on because Musk is Musk, and he's able to generate a lot of hype that someone used to get funding. The rest is media frenzy.
It's important to note that Musk is NOT putting his own money into it, and has nothing to do with the company trying to make it.
 

Offline EEVblog

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Re: The Hyperloop: BUSTED
« Reply #81 on: July 29, 2016, 12:42:08 am »
BUSTED means it isn't a practical solution.
The claims made by solar roadways can be demonstrated to be impossible on the back of an envelope. Not just impractical, but forbidden by the basic laws of physics. The story for batteriser is similar.
The hyperloop could be constructed, theoretically. It might be insanely dangerous. It might cost more money that the entire world has. It might be entirely pointless, and indeed massively impractical. But it is not outright impossible.

You really need to read my sentence above again.
 

Offline Alex Eisenhut

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Re: The Hyperloop: BUSTED
« Reply #82 on: July 29, 2016, 12:44:08 am »
Hyperloop is different - this is a new concept and most of the technology has yet to be developed. 

It's a concept that is nearly 100 year old.

...and already used on the moon since 1999.

 

Offline mtdoc

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Re: The Hyperloop: BUSTED
« Reply #83 on: July 29, 2016, 12:57:03 am »
Hyperloop is different - this is a new concept and most of the technology has yet to be developed. 

It's a concept that is nearly 100 year old.

I thought it was obvious that I was referring to the specific case of using it ("the compressor within a tube" concept) for mass transit on a large scale - and not the general concept of transport of an object in a low pressure tube - which has been around and used for years...

The comparison to solar roadways is bogus in either case.
« Last Edit: July 29, 2016, 01:19:02 am by mtdoc »
 

Offline boffin

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Re: The Hyperloop: BUSTED
« Reply #84 on: July 29, 2016, 01:19:53 am »
You Europeans are missing the context, which is the enormous boondoggle/scam called California High Speed Rail.  Hyperloop may seem implausible, but at least it has a chance, where most people think CHSR is guaranteed to fail :(

Madrid - Barcelona; 621 km
San Francisco - Los Angeles; 616 km

The former used to be the busiest air route in the world (seats/day), now there's a high speed train, every 30 minutes that takes between 2h30m (nonstop) to 3h10m (two stops) at 300kmph, and MAD-BCN isn't in the top 20 air routes in the world.



 

Offline helius

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Re: The Hyperloop: BUSTED
« Reply #85 on: July 29, 2016, 01:33:21 am »
Hyperloop is different - this is a new concept and most of the technology has yet to be developed. 

It's a concept that is nearly 100 year old.

I thought it was obvious that I was referring to the specific case of using it ("the compressor within a tube" concept) for mass transit on a large scale - and not the general concept of transport of an object in a low pressure tube - which has been around and used for years...

The comparison to solar roadways is bogus in either case.

In fact, its specific case of mass transit has been in use for almost 200 years.
https://en.wikipedia.org/wiki/Atmospheric_railway
 

Offline Mark_Of_Sanity

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Re: The Hyperloop: BUSTED
« Reply #86 on: July 29, 2016, 04:28:31 am »
Ok comparing this to solar roadways is just disingenuous.

With the solar roadway it's not a case of disproving it, it's a case of asking what's the benefit?
What is the point of combining solar panels with roads?
Conceptually right from the start there's not even a perceivable benefit to be understood there?

Where as with the vactrain i.e. Hyperloop, the supposed benefit is frictionless travel.
Maglev to get rid of wheel friction and a vacuum environment to get rid of air resistance.
On concept there IS a benefit and individually, the technologies already DO exist.

Vacuum tubes exist in the likes of LIGO which is probably the thinnest vacuum in the world and until
recently TWO completely different forms of Maglev trains existed as well.
The german transrapid and the japanese one (don't know it's name).

So like I said, completely unfair and disingenuous to suggest that this is in the same line as the
conceptually stupid solar roadway project.
 

Offline mtdoc

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Re: The Hyperloop: BUSTED
« Reply #87 on: July 29, 2016, 04:33:37 am »
Hyperloop is different - this is a new concept and most of the technology has yet to be developed. 

It's a concept that is nearly 100 year old.

I thought it was obvious that I was referring to the specific case of using it ("the compressor within a tube" concept) for mass transit on a large scale - and not the general concept of transport of an object in a low pressure tube - which has been around and used for years...

The comparison to solar roadways is bogus in either case.

In fact, its specific case of mass transit has been in use for almost 200 years.
https://en.wikipedia.org/wiki/Atmospheric_railway

Interesting history. Thanks for the link. But of course very different than the hyperloop.
 

Offline EEVblog

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Re: The Hyperloop: BUSTED
« Reply #88 on: July 29, 2016, 04:38:32 am »
Where as with the vactrain i.e. Hyperloop, the supposed benefit is frictionless travel.
Maglev to get rid of wheel friction and a vacuum environment to get rid of air resistance.

Why bother?
I've been on a MagLev train at 430kmh, it works, it's safe, it's robust, and it's fast enough.
To go through orders of magnitude more engineering complexity, safety, and security to get the only tangible benefit which is double the speed seems pretty darn stupid to me.
 

Offline EEVblog

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Re: The Hyperloop: BUSTED
« Reply #89 on: July 29, 2016, 04:42:44 am »
So like I said, completely unfair and disingenuous to suggest that this is in the same line as the
conceptually stupid solar roadway project.

It's a completely fair conceptual benefits comparison I think.

The benefit of Hyperloop is double the speed of existing proven MagLev at the cost of orders of magnitude more complexity

The benefit of Solar Roadways is using existing road surface area at the cost of orders of magnitude more complexity.
 

Offline EEVblog

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Re: The Hyperloop: BUSTED
« Reply #90 on: July 29, 2016, 04:51:15 am »
The claims made by solar roadways can be demonstrated to be impossible on the back of an envelope. Not just impractical, but forbidden by the basic laws of physics.

Yes, many of the claims are. But the concept is perfectly plausible, and can actually be implemented and will produce energy. It's just horribly inefficient, non robust, and impractical on a large scale. It is guaranteed to fail miserably. But it can work, that is why it's so attractive to so many people.
(Of course I think the Colas Wattway project is much more practical than the stupid Solar Roadways glass tiles, but that's beside the point)
 

Offline mtdoc

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Re: The Hyperloop: BUSTED
« Reply #91 on: July 29, 2016, 04:55:25 am »

Why bother?
I've been on a MagLev train at 430kmh, it works, it's safe, it's robust, and it's fast enough.
To go through orders of magnitude more engineering complexity, safety, and security to get the only tangible benefit which is double the speed seems pretty darn stupid to me.

That is a completely fair assessment and one I would not argue with but it is completely different than TF's attempt at "busting" it.

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It's a completely fair conceptual benefits comparison I think.

The benefit of Hyperloop is double the speed of existing proven MagLev at the cost of orders of magnitude more complexity

The benefit of Solar Roadways is using existing road surface area at the cost of orders of magnitude more complexity.

But that comparison has nothing to do with the supposed "busting"

The difference is that the solar roadways claims regarding solar output (and therefore benefit of the roadway) are easily and verifiably false where as the possibility of building a hyperloop with the benefits as envisioned by Musk is unknown - despite TFs elaborating on some of the challenges.  They may turn out to be insurmountable - but at this point that is an unknown.
 

Offline EEVblog

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Re: The Hyperloop: BUSTED
« Reply #92 on: July 29, 2016, 05:23:08 am »
That is a completely fair assessment and one I would not argue with but it is completely different than TF's attempt at "busting" it.

You're taking it too literally. He's just pointing out the various problems.
In essence what he's saying is the same thing, it's just not going to be practical.

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The difference is that the solar roadways claims regarding solar output (and therefore benefit of the roadway) are easily and verifiably false where as the possibility of building a hyperloop with the benefits as envisioned by Musk is unknown - despite TFs elaborating on some of the challenges.  They may turn out to be insurmountable - but at this point that is an unknown.

Unknown? Rubbish. It something you can easily do back-of-the-envelope calcs on to ascertain the potential problems as TF has done.
You just don't like to admit that ultimately he's going to be right.
I can smell this engineering disaster a mile again, I'm surprised you can't.
 

Online Someone

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Re: The Hyperloop: BUSTED
« Reply #93 on: July 29, 2016, 05:40:31 am »
Where as with the vactrain i.e. Hyperloop, the supposed benefit is frictionless travel.
Maglev to get rid of wheel friction and a vacuum environment to get rid of air resistance.

Why bother?
I've been on a MagLev train at 430kmh, it works, it's safe, it's robust, and it's fast enough.
To go through orders of magnitude more engineering complexity, safety, and security to get the only tangible benefit which is double the speed seems pretty darn stupid to me.
You could use the same argument to suggest that "high speed rail" as extensively used in Germany and the UK at half the speed and half the cost again would be sufficient. Maglev has some unique features making it attractive for short routes (Airport-CBD links are just about perfect) but its not a sure thing.

Externalising costs of the infrastructure makes air travel more cost effective than rail at the moment, and the hyper loop appears to be no more energy efficient than conventional rail so its hard to find much attractive about it.
 

Offline Mark_Of_Sanity

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Re: The Hyperloop: BUSTED
« Reply #94 on: July 29, 2016, 06:02:36 am »
I disagree, sure it maybe impractical but we don't know that for sure until we really test it out.

Here's an excerpt from wikipedia page on drag,

"Power

The power required to overcome the aerodynamic drag is given by:   ...

Note that the power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome air drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW).[16]

With a doubling of speed the drag (force) quadruples per the formula. Exerting four times the force over a fixed distance produces four times as much work. At twice the speed the work (resulting in displacement over a fixed distance) is done twice as fast. Since power is the rate of doing work, four times the work done in half the time requires eight times the power.
"

So in light of that problem, an engineer wondering as to how much better a train would function in a low pressure environment, or
a vacuum, isn't a completely disconnected thought, unlike with the solar roadway project.
And suppose that doubling of the speed came for roughly the same energy expense as a train traveling half that speed through
air at 1atm? That would be getting a level of performance that would normally require 8 times more power!

Now lets use the transrapid as an example, which I am fairly sure is the one you rode if this was in China.

Again wiki states,

"The normal energy consumption of the Transrapid is approximately 50 to 100 kilowatts (67 to 134 hp) per section for levitation and travel, and vehicle control. The drag coefficient of the Transrapid is about 0.26. The aerodynamic drag of the vehicle, which has a frontal cross section of 16 m2 (172 sq ft), requires a power consumption, at 400 km/h (249 mph) or 111 m/s (364 ft/s) cruising speed, given by the following formula ... 3.53MW"

So under the hyperloop concept, assuming the utmost ideal result, you would be getting double the normal performance
at 3.53MW instead of 28.24MW!

That seems worth trying out imo.

« Last Edit: July 29, 2016, 06:17:00 am by Mark_Of_Sanity »
 

Offline mtdoc

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Re: The Hyperloop: BUSTED
« Reply #95 on: July 29, 2016, 07:11:03 am »
It something you can easily do back-of-the-envelope calcs on to ascertain the potential problems as TF has done.

I think pointing out potential problems is very different than "busting" something. As others have said, it dilutes the "busted brand". It will just lead to a boy-who-cried-wolf phenomenon.

How easy would it have been to do back of the envelope calculations to ascertain the potential problems of proposed NASA missions 60 years ago?

I've already said that i don't think it is likely to be built but TFs videos did not convince me that it will be because of insurmountable technical difficulties - It's too soon to say IMHO. But i'll admit I say that simply as a science/technically literate outside observer and not as an engineer.

In any case I'm glad companies like Hyperloop One are attempting to overcome the technical hurdles. It will be fun to see how far they get.

I am dissapointed that TF seems to be tryiing to milk the success of the solar roadways "Busted" videos and in that way is guilty himself of using hype to sell a product.
 

Offline EEVblog

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Re: The Hyperloop: BUSTED
« Reply #96 on: July 29, 2016, 07:19:03 am »
You could use the same argument to suggest that "high speed rail" as extensively used in Germany and the UK at half the speed and half the cost again would be sufficient.

Maybe, but at some point planes are going to beat them.

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Maglev has some unique features making it attractive for short routes (Airport-CBD links are just about perfect) but its not a sure thing.

Sure, but from a practical engineering point of view I know where I'd put my development money.

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Externalising costs of the infrastructure makes air travel more cost effective than rail at the moment, and the hyper loop appears to be no more energy efficient than conventional rail so its hard to find much attractive about it.

Agreed, especially with all the problems.
 

Offline EEVblog

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Re: The Hyperloop: BUSTED
« Reply #97 on: July 29, 2016, 07:25:12 am »
So in light of that problem, an engineer wondering as to how much better a train would function in a low pressure environment, or
a vacuum, isn't a completely disconnected thought, unlike with the solar roadway project.
And suppose that doubling of the speed came for roughly the same energy expense as a train traveling half that speed through
air at 1atm? That would be getting a level of performance that would normally require 8 times more power!

Sure, but if it comes at the expense of orders of magnitude more engineering complexity, safety and robustness concerns etc, then it's a dead duck idea.
And to any practical design engineer without blinkers on, this looks, smells, and quacks like a dead duck.
The main problem with the hyperloop is the near vacuum environment and all the associated issues that go along with it. Only a fool would think this is the future as a robust usable mass scale public transit technology running 24/7 over massive distances.

Let's be honest, if anyone other than Elon Musk had proposed and started this hype, and it was just some random startup company, it would have been laughed at and wouldn't be taken nor discussed the least bit seriously. It's a pure media driven Musk inspired hype machine.
« Last Edit: July 29, 2016, 07:33:12 am by EEVblog »
 

Offline EEVblog

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Re: The Hyperloop: BUSTED
« Reply #98 on: July 29, 2016, 07:29:00 am »
How easy would it have been to do back of the envelope calculations to ascertain the potential problems of proposed NASA missions 60 years ago?

The Solar Roadways, uBeam, and Fontus apologists make the exact same comparison, and they are massively and demonstrably wrong. Don't go there, you'll only dig an embarrassing deep hole for yourself.
 

Offline Kilrah

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Re: The Hyperloop: BUSTED
« Reply #99 on: July 29, 2016, 07:44:13 am »
It something you can easily do back-of-the-envelope calcs on to ascertain the potential problems as TF has done.

I think pointing out potential problems is very different than "busting" something. As others have said, it dilutes the "busted brand". It will just lead to a boy-who-cried-wolf phenomenon.

How easy would it have been to do back of the envelope calculations to ascertain the potential problems of proposed NASA missions 60 years ago?

I was going to say the same, the context is very different. Solar roadways can use existing technology, and it has been demonstrated, partly by Dave that regardless of any further development, and considering perfect components there would be no siginificantly useful output. That is BUSTED. It can't work. Its very definition implies constraints that limit its usability, you can't develop something new we don't know about yet and make it significantly useful compared to competing technologies to produce energy (some of which being just put the panels somewhere else).

A project like the Hyperloop is completely different, it is useful by definition because it has no competition. Assuming it was made and held its promises it would allow for something (a 560km trip in 35min) that nothing else can provide. This likens it to things like Concorde, space exploration, or more recently for example the F-35. They may be hyper complicated, require decades of development of technologies nobody has even thought about yet, be a money pit and have dubious usefulness in the end, but because they had the promise of providing something that nothing else could achieve and someone was interested in it whether it's by deeming it useful or just as a pride/prestige thing they have been done. Could very well happen here.

Again the key difference is competition. You can BUST something for which there are alternatives, and back of the envelope calcs show that regardless of how good the project is the alternatives will always be better... but you can't BUST something that aims to provide something for which there is no alternative unless you provide an alterntive that proves ability to achieve the same goal. For such things it is NOT engineering practicality that defines the feasibility of the project, it's entirely in the hands of someone who will either say "let's do this" or not.

The only way you could BUST Hyperloop is with something like "a train in a vacuum tube is a stupid way to do 560km in 35min, you should do it that way instead becasue [pertinent reasons]".
« Last Edit: July 29, 2016, 07:50:51 am by Kilrah »
 
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