How Hyperloop One Went Off the Rails
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Maglev trains have been proposed before; there's nothing particular new or novel about the idea. One of the bigger problems with maglev is that the tracks are very expensive. One of the exciting things about the Hyperloop concept was that the tracks should be much cheaper, since all you need is a steel tube.
Is it really right to call it a Hyperloop if it eschews the original concept in favor of building a maglev train in an evacuated tube? Feels like they're taking a totally different idea and just using the Hyperloop name to generate hype.
In my opinion the Hyperloop is an insane idea and these companies are suspect. It seems more likely that they're the 2010s version of the Moller Aircar, something to keep "almost there" for decades while you milk investor money.
Of course, most of the vacuum tube proposals require a vacuum of something like 0.001 atmospheres, which is incredibly problematic as well....
Speed figures up to 10000 km/h were thrown around (assuming near perfect vacuum).
It just seems like if it was done this way it would be so much simpler and therefore cheaper to build.
Only problem is that it would turn the idea into 'just another maglev train'.
We aren't using the type of maglev that's used in maglev trains where the track is magnetized and super expensive. We're using ArxPax hover engines[1]. They just spin a Halbach array[2] super fast and generate a hovering force off of an aluminum track.
The winning team of Design Weekend last January, MIT, is also using magnetic levitation but they are doing a passive version. The track still isn't magnetized, but their magnets generate their eddy currents just by the movement of the pod. It sort of "takes off."
The first reason we -- and others in the competition, though not the majority I believe -- went with maglev is that the we (well, the Mechanical Engineering students, I'm CS) couldn't find air-skis that worked at high speeds. Elon mentioned at Code Conference that they'd been tested up to Mach 1.1 but when I told the ME's of that they said they hadn't found anything they could use nor any research showing that the air being pushed out of the ski "keeps up" with the pod at high speeds.
In addition to the speed problem with air skis, they also hover much lower off the ground than the maglev and require much higher tolerances on the track (more expensive).
Part of the reason to have the competition is to try a bunch of different ideas at once and see what works best. I do believe there are plenty of teams that will be testing air-skis on the track at competition weekend. We'll see how it goes.
I think the tube itself could be made reasonably cheaply compared to the CA high speed rail system. We transfer oil in huge pipelines with high pressure differences so I think it should be pretty feasible to keep it properly sealed. I'm more worried about the cost of the safety mechanisms and them being able to secure the land rights.
Elon mentioned at design weekend that initial versions could even use wheels if they aren't going over ~250MPH.
The Hyperloop competition (not Hyperloop One) had an aluminum rail down the track center, and the winning team (MIT) levitated magnetically against that at 15mm height. Maglev against an aluminum rail is energy-intensive, but they were only making a trip of a thousand feet or so, and could do it on batteries without using superconducting magnets.
Maglev in vacuum is an old idea. That's called "Vactrain". There have been many proposals, none built.
[Technical nitpick first: tube is a structural element, while pipe is something that can hold pressure.]
The price of pressure-rated steel pipe is roughly proportional to the diameter squared. At 132 inches in diameter, the hyperloop pipe itself would cost at least $600/ft. It would also weigh > 1000 lbs/ft, so the support system would be absolutely massive and probably double that price. That's just the cost of raw materials.
For comparison, Elon Musk's total cost estimate is $1400 per foot per pipe [$6 billion total cost, 380 miles, two pipes], so I'm inclined to say that his estimate might be a bit optimistic.
From what I can tell, total cost per foot for maglev is estimated around $6000/ft. [US highway construction cost per lane per foot is also around that number.] But I understand those numbers as the total cost including also engineering work, shipping/logistics, actual building work, buying the land etc. While my $1200/ft estimate is just raw materials.
So if we as a very coarse estimate say raw materials is 1/4 of the price, hyperloop is not significantly cheaper than maglev.
Fyi there is a cost breakdown on pp55 of the Hyperloop PDF, which lists the tube construction costs as half what you specify. What kind of "pressure tubes" are you referring to for these cost estimates? http://www.spacex.com/sites/spacex/files/hyperloop_alpha-201...
Just look at the planned LA-SF high speed rails. It suffered delays and cost overruns over and over again. The latest figure of $68B most likely will not be enough[1].
And that is a garden-variety high speed rail that has been proven all over the world for decades. Hyperloop is completely unproven and requires construction of end-to-end airtight tubes.
If a few hundred miles of vanilla high speed rail costs $70B and counting, how much would hyperloop cost? $500B? $1T? It'll never work economically.
[1] http://www.latimes.com/local/california/la-me-bullet-train-c...
I think it remains to be seen whether it can actually be built in this manner. Regardless, there may be still be noise concerns and the problem of creating an unsightly above ground structure. Plus, the very idea of having one close by might be frightening for many.
Of course, that makes it kind of silly to compare it as an alternative to HSR, whose high costs include acquiring land in the very expensive neighborhoods of the population centers it was supposed to serve, so that it would actually be a useful means of connecting population centers.
A significant and costly part of the high speed rail project is the commuter rail bit which requires of extensive/expensive work on right of ways in developed areas. And big engineering challenge is constructing tunnels to connect to the Los Angles basin[1]. A hyper loop system would need the same infrastructure to provide the same service[2].
[1] 14 mile tunnel under the San Gabriel Mountains. This is part of the reason they punted and decided to work on the northern section first.
[2] The original design I saw for the hyper loop made it seem to be a way for wealthy people to get from their ranchetts north of Los Angles to the Bay Area.
If not internal squabbles and lawsuits, the practical laws of nature would eventually have to be reckoned with (just like with Solar Freakin Roadways)
There would be no sonic "shock wave" killing everyone in the tube in the event of a breach. Viscous drag on the tube walls would reduce the flow velocity to highway speed in only a couple km. The wave front spreads out, becoming a gradual pressure rise.
The entire tube would be designed for rapid repressurization (under 60 seconds). The cars can easily stop in 15-20 seconds since the passengers are strapped in and possibly in seats facing backward to arrest braking forces.
Expansion joints are easily accommodated at the end stations, and the slight leaks from the sliding interfaces are compensated by mechanical pumps (easy to maintain 1/1000th of an atmosphere, damn near impossible to maintain 1/1000000 of an atmosphere for true vac trains given the linear decrease in vacuum pumping mass flow at low pressures and the need for turbomolucular pumps and/or cryopumps at those pressures).
There's a great need for pumping near the end stations anyway due to residual air entering around the pod in the airlock. They'll pump down the majority of the pressure of course, but due to the exponential drop in pumping speed over time it makes little sense to make passengers wait a long time and pump it down to the exact same pressure when they can cut it off early and just let the tube pumps make it up. Even on the space station (where air is very expensive) they only pump the airlock down part-way and vent the remaining residual atmosphere so the astronauts (whose time is also expensive) don't have to wait.
The same sound absorbing layers and vibration isolation technology that's used on jet planes could also be used if needed.
But strawman/direct attacks aside.
In my experience when one engineer is disagreeing with a team of engineers, they're wrong or the team a fundamental misunderstanding of the problem they're working to solve.
Now take startups that just want VC money with no intention of producing a product, a team of engineers that likes their salaries and you'll get a fake consensus very easily.
Even if those engineers clearly have a financial incentive to make biased claims?
If you are really concerned with this why are you posting on a forum literally owned by a SV Billionaire?
Buts let's pretend you are rational. How does a master in chemistry grant you knowledge of mechanical, structural, and fluid engineering. If you say they're both Math/STEM fields, then why aren't chemistry professors, and comsologist certified electricians? It's related by the same logic.
Only if you fall prey to logical fallacies. Noting that not all engineers are motivated to be maximally honest doesn't require that you completely mistrust literally everyone. False dilemma.
> If you are really concerned with this
What is it, exactly, that you think I'm concerned about? And how concerned do you think I am?
I can't help you with your chemistry/STEM straw man.
How is this a strawman? Because it is literally the crux of your argument that a masters of chemistry is an expert on structural engineering and fluid dynamics?
His videos on the hyperloop are pretty comprehensive and succinct about their reasoning. Why not watch them instead of mindlessly repeating the same strawman argument that every other Elon Musk fanboy/fangirl left on his videos?
https://www.youtube.com/watch?v=DDwe2M-LDZQ https://www.youtube.com/watch?v=RNFesa01llk
Right? Surely Thunderf00t is qualified to make some of the criticism he made?
I would agree that there are likely a few areas in which his criticism exceeded his understanding, though I have yet to read a criticism of his criticism that doesn't mis-represent his claims.
I still don't see the specific relevance of mdorazio's comment to computerex's.
Doesn't mean he's wrong, just means he doesn't have special standing.
To me, Computerex seems to simply be saying "Thunderf00t has sufficient general knowledge of science to make his debunking videos worthy of watching".
You mention 'special standing', which suggests an 'all or nothing' approach to categorizing people's status and knowledge, rather than a more reality-accommodating recognition that expertise and knowledge are a matters of degree.
Mdorazio did not state what you say they did, they instead asked a leading question in which words were placed in another person's mouth. Further, Mdorazio would be incorrect to state that "from the perspective of mechanical engineering and fluid dynamics, he is in fact an average Joe on the street." because the average Joe on the street, relatively speaking, is not as equipped as Thunderf00t to understand issues of mechanical engineering and fluid dynamics. I'm not saying that Thunderf00t is or is not properly equipped to make each criticism, just pointing out the problem with 'all or nothing' style thinking here.
You would be right to question whether Thunderf00t has sufficiently advanced and detailed knowledge to make each and every one of the criticisms that he makes, but this would depend on the specific criticism and the specifics of Thunderf00ts knowledge.
As it happens, not even having a PhD in fluid mechanics would guarantee that the critic has the relevant knowledge, nor is thinking through the problem correctly.
Phil Mason, PhD in chemistry, and work in nutrition, physics, and nuclear physics, with 34 published papers to his credit, now he's one sassy frood.
I guess you don't know how much dedication and effort it takes to earn a good PhD. A PhD in STEM teaches you how to be a good scientist, how to think about problems and how to conduct research. These skills are very useful in pretty much every discipline imaginable.
Not to mention the fact that a PhD in chemistry warrants a very heavy mathematical/physics background. If you honestly think that Thunderf00t has the same credibility as some average Joe on the street about Hyperloop/physics/engineering, you must have a very religious background.
However, I would absolutely agree with you that Thunderf00t is adequately qualified to make most of the criticism that he has made in a variety of his debunking videos. Thunderf00t is doing our culture a valuable service by debunking that ridiculous re-breather apparatus, 'solar freakin roadways', and the allegedly endless water bottle. Its sad that people are so ignorant of basic science that they are taken in by this snake oil.
I thought that his main message was that people are over-selling the feasibility of the hyperloop and playing down the incredible engineering challenges and dangers.
We aren't so far away from the days when your actual name was simply whatever you called yourself.
"Until 2014, his name had been Kevin Brogan, but he legally changed it to merge names with his wife, Bambi."
The Hyperloop might be worth pursuing it it were 10% of the price of HSR, but that's just not anywhere near the case, as other commenters have duly pointed out.
Hyperloop supporters claim that the Hyperloop is more economically feasible than traditional high-speed rail like the Shinkansen. This is, of course, based on estimates which can only be trusted somewhat. However, those estimates are by no means ridiculous.
The original Hyperloop proposal is interesting reading, you might want to take a glance at it. It covers the economics, including issues like land use rights, which are a major component in any high-speed transport system which must necessarily have a course with limited curvature.
The location is also a big issue. Consider the profitability of Japan's Shinkansen in light of the high population density and the ease in which you can serve 25 million people with a single 250 mile train line--other Shinkansen lines are not as profitable to run.
To be clear, I'm relating the arguments in favor. I'm also fairly skeptical.
Same speed, cheaper, exists today, no need to build tracks :)
After all, maybe we'll have battery powered airplanes some day or maybe we'll just use gliders for shorter distances though maybe that wouldn't be as great for a reliable transport.
I would rather hoped for suborbital passenger transportation. 10x improvement: delivered (and engineering-wise, about as hard as Hyperloop). People are meant to fly, not stay tethered to the Earth forever.
IndexMundi gives ~5 million barrels/day of jet fuel consumption, 2012.
http://www.indexmundi.com/energy/?product=jet-fuel
That compares with 90 mbpd global petroleum consumption in 2012 (BP Annual Statistical Review, 2016)
That's 5.5% of petroleum consumption, which is about 1/3 of total energy (BP, 2016). Carbon allocation is to petro, gas, and coal, so 2-4% of total CO2 emissions actually is about right.
OK, you pass ;-)
As of hyper-loop, even if, arguendo, it works; every other major type of transportation eventually failed. Trains do derail sometimes and planes do fell off the sky even if very rarely. I seen some pretty scary pictures in my life, and once seen a deadly car accident (head-on collision at 80mph) myself where you couldn't distinguish where the dashboard ends and actual human body begins, but I can't imagine how it would feel or look like when a body of tissue organs and blood crashes down after driving 780mph.
Long-distance air travel can be pretty efficient, and compares favourably with personal auto travel -- you'll consume about as much fuel driving across the United States in a car as you would on a plane, and travel at about 1/10th the speed (though you'd also be free to stop and take in the scenery where you wanted).
What ground-based alternatives to air travel offer most specifically is alternate modes of energy supply. A fixed-track system (conventional or high-speed rail, maglev, hyperloop) can have energy delivered electrically, meaning transport is divorced from fossil fuels.
There's some disagreement in this thread of total CO2 emissions, which translate strongly to fuel consumption (burning a given mass of kerosene, a/k/a jet fuel, produces a fixed amount of CO2, no matter where you do it). The figure I've seen is about 6% of global emissions, and recently an 11% of US emissions figure (possibly a result of falling electricity emissions due to reductions of coal use, now that I think of it).
I'm actually not a fan of Hyperloop -- similar systems were proposed in the 1970s, explored by RAND, and rejected on multiple bases. But a high-speed, ~300 kph wheeled rail connection between regional hubs in the US does seem quite sensible. It's working out well in Europe.
When a plane ticket e.g. from Geneva to Barcelona can be bought for $40, trains really can't compete, at least between countries. They are slowly dying out on government subsidies.
I'm really disappointed to see Hyperloop One come crashing down, but I'm not surprised by it. Those who have worked closely with him have learned that Shervin Pishevar is absolutely toxic. There's not much else I can say without violating HN's civility rules, but this seems to be an open secret in SV. Some people love him, some just tolerate him, but many say they will never work with him again.