xeni — 2013-07-16T15:12:31-04:00 — #1
The “Hyperloop,” a hybrid new form of transportation proposed by Tesla and SpaceX founder Elon Musk, would shrink the duration of a trip from San Francisco to Los Angeles to 30 minutes, at a speed of almost 800 miles an hour. [NYTimes.com] READ THE REST
geekman — 2013-07-16T15:19:06-04:00 — #2
I heard those things are awfully loud...
digitalartform — 2013-07-16T15:22:52-04:00 — #3
When I was a kid in the 70s I read that a maglev train in a vacuum tube could theoretically travel the length of any secant connecting any two points on Earth in the same amount of time by gravity alone, downhill half the way and uphill the other half. If I recall, the time was on the order of an hour.
jambles — 2013-07-16T15:33:48-04:00 — #4
This thing always makes me think of the Alameda-Weehawken burrito tunnel
jandrese — 2013-07-16T15:35:22-04:00 — #5
Thermodynamics says no to the infinite travel between two points at the same height idea. You aren't allowed to break even. Also, "any two points on the Earth" and "all terrain between the points must be at a lower level" are mutually inconsistent goals. Sustained hypersonic travel using only the force of gravity from the Earth's surface is totally loony too.
Anyway, the extremely sketchy detail in that article makes this Hyperloop thing seem just as unlikely. He wants to build the entire system for 6 billion dollars, but land and easements in California alone will cost more than that. He also wants it to be supersonic and also ground effect, a mode of transportation that is utterly untested right now. On the face of it this idea is crazypants and will go nowhere.
aaronbauman — 2013-07-16T16:17:25-04:00 — #6
If you like the sound of this idea, please contact me about acquisition of a particularly piquant bridge linking two particularly populous boroughs in a particularly popular East Coast city.
galaxies — 2013-07-16T16:21:22-04:00 — #7
obeymybrain — 2013-07-16T17:06:56-04:00 — #8
digital Artform: They used this idea in the Total Recall remake movie last year. They called it The Fall I think. The basic idea is that it would take 42 minutes to get to any point on earth by traveling a straight line tunnel through the planet using only gravity to move. Though the one in Total Recall only took 17 minutes.It's called the Gravity Express or Gravity Train
rocketpj — 2013-07-16T17:08:04-04:00 — #9
It would be crazypants if it weren't from someone who has actually done a few things for real. Not sure about this one - is he planning to run it on the ocean? That could, if done right, be a workaround for all the land-based barriers.
Interesting that he is opensourcing the design. Cue patent trolls.
bizmail_public — 2013-07-16T17:08:14-04:00 — #10
Elon Musk's nose for government subsidy is truly a thing of beauty.
SpaceX has only one customer (the federal government), Tesla requires financial subsidy to be viable ( http://www.forbes.com/sites/patrickmichaels/2013/05/27/if-tesla-would-stop-selling-cars-wed-all-save-some-money/ ), and the State of California just happens to have billions of dollars for high speen rail laying around unspent.
penforhire — 2013-07-16T17:50:40-04:00 — #11
I'd say it was the raving of a lunatic if it wasn't Musk. He's already accomplished amazing so now he's aiming at "nearly impossible."
From an engineering perspective I have a hard time imagining how that much volume of tube is kept under enough vacuum and how to make it tamper resistant - shooting some holes in tube might be bad. And what about a big earthquake? Or a truck hitting the support beam? I don't have a problem with the PSI load on the tube (roughly one atmosphere, maximum) but it takes a LOT of vacuum pumps (and energy) to evacuate chambers that are orders of magnitude smaller than this.
You know what diffuses through almost anything when you pull high vacuum? Atmospheric hydrogen. Which is also harder to pump out. Of course if low pressure is maintained then it, along with oxygen, should not build up to flammable levels. Just noodling over possible unintended consequences.
I can see how it could be made safe, with enough braking force available in emergencies and sensors to show a stopped "car" ahead. The cars themselves need to be really well sealed and have a supply of compressed atmosphere. A leak into the vacuum tube would asphyxiate us.
I don't yet follow why it would be cheaper than a conventional train ride. Does maglev make the total work done, in a physics sense, less? Or put another way, are wheels on rails THAT inefficient by comparison?
dmpalmer — 2013-07-17T01:51:34-04:00 — #12
SpaceX has many non-government customers, with three commercial launches planned from Sept to Dec of this year. Tesla got a $465M loan from the US Government in 2010, but has already paid it back 9 years early. TSLA had a bad day today, so it is only about quadruple its value from a year ago.
If Musk does what he says he can do by sucking $6B from the California's government, then how is it better for CA to pay $60B for something nowhere near as good?
I didn't know that Delos D. Harriman was also the guy from The Roads Must Roll, but that seems to be how the future is playing out.
speleothem — 2013-07-17T02:55:48-04:00 — #13
I wonder if he'd want to use an Atomic Subterrene to actually dig the tunnel?
bcsizemo — 2013-07-17T05:34:46-04:00 — #14
Come on guys, obviously Mr. Musk just recently found all those old Soviet era Ekranoplan videos on Youtube:
High speed ground effect, more or less safe cause if the engine fails it'll just "land" in the water and float.
echolocatechoco — 2013-07-17T10:45:08-04:00 — #15
I look forward to riding this to my local space elevator, which will be complete around the same time.
jacobin — 2013-07-17T11:23:14-04:00 — #16
petronius — 2013-07-17T11:54:31-04:00 — #17
gjbloom — 2013-07-17T12:39:57-04:00 — #18
There could be several advantages to an undersea vacuum-tube. It could be almost neutrally buoyant, and thus lightly tethered to the bottom, avoiding most of the shock and strain from earthquakes. Being under water, there should be less hydrogen seeping in through the stainless steel. Having waves above the length of the track might allow electric field generators and maintenance pumps to be powered by renewable wave energy. Being underwater, tsunamis could roll right over it with no effect. The tube would become somewhat less accessible to people bent on destruction - they'd have to own a boat and scuba gear at a minimum; no plinking the pipe with 50-cal sniper rifles from a safe distance. Maintenance might be easier, as the whole tube might be floated up to the surface where an enclosing maintenance ship could proceed along its length, with access to all sides. Still crazypants, but engagingly so.
clamb — 2013-07-18T11:04:42-04:00 — #19
Wouldn't it be cheaper just to move one city next to the other?
penforhire — 2013-07-18T17:57:08-04:00 — #20
Underwater tubes have some other issues, like an extra atmosphere of external pressure for every 33 feet of depth. Neutral buoyancy seems like a good idea but it still requires rigid anchoring (sensitivity to earthquakes AND wave action) to handle the occasion of a 'car' stopping in case of emergency. Unless you envision a tube so flexible it can just drop from the extra mass of the stopped car.
It is also an extra layer of hostile environment in the case of a bail-out. If they are above ground the car might have a means of popping a tube 'hatch' into open air to escape. Admittedly the tube's vacuum is an even more human-hostile environment than under water.
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