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The Race To Create a Hyperloop Heats Up (wsj.com)
An anonymous reader writes: When Elon Musk unveiled his idea for the "Hyperloop" transportation system based on capsules zipping through depressurized tubes, much was made about the enormous technical challenges the system would face in development. However, that didn't stop a number of companies and organizations from starting to work on it. Several companies are pushing the development work hard, and it's shaping up like a race to a workable prototype. University teams are only increasing their efforts as well. "The Illinois team enters the SpaceX contest with a strong competitive edge. This is its fourth Hyperloop design project, the first dating to fall 2013, and the Hyperloop is now a part of the MechSE curriculum. The team has assembled an interdisciplinary network of faculty from aeronautical engineering, thermal dynamics, mechanical engineering, electronic engineering and software, and two of the team members have interned at SpaceX."
"The pod has been pressurized to minimize the G forces effects on a passenger."
Really? How is that little trick performed?
I love Jesus, except for his foreign policy.
they should bury it so it can be a straight line tube cutting into the earth's curvature. Then you can just "fall" from Los Angeles to SF with no propulsion needed. The theoretical transit time, ignoring the friction, is 43 minutes. the energy you need to supply is to overcome the friction. Since gravity will be both accelerating this and decelerating this there's no need for a complex propulsion system, decelleration system with energy reclamation. Less to go wrong, and less abrupt acceleration of the passengers, and probably greater safety.
Of course the hard part of this is you have to tunnel underground to make a straight line cutting in to the earth. Since LA to SF is about 400 miles along the surface and the earth's circumference is about 25000 miles this means arc length is about 0.016 radians. thus 25000/2/pi*(1-cos(0.016/2)) = 0.127 miles.
so the center of this would be roughly 1/8th of a mile buried or 672 feet at the deepest point (ignoring the mountains). This doesn't seem radically crazy as a depth for boring a hole.
Some drink at the fountain of knowledge. Others just gargle.
Since the top speed is barely supersonic, wouldn't the g-forces here be comparable to a commercial jet plane?
boy, painting this fence is really fun.
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
1. the majority of americans outside a handful of cities still consider public transportation to be a mark of poverty and avoid it at all costs. others cant be bothered to even consider a greyhound to the next state, let alone a train, and once they arrive the local public transit infrastructure based on their destination is either so poor as to be unusable or nonexistent through legislative fiat.
2. We cant keep up. our bridges, roads, highways and railroads are crumbling further into the dirt each year, and neither body of legislation seems capable of passing meaningful funding. the hyperloop would surely face the same fate as a majority invested government project that eventually turned into public private, then abandoned once the payout wasnt suitable for corporations, and finally maintained at about a quarter of its original capacity.
3. the initial projection for this works project (and, it would be a works project) is six billion dollars. America cant manage to keep its government running for more than 2 years at a time in this foul year of our lord 2015. It wont fund education, its states wont fund healthcare, and its been cutting federal public transit funding for 35 years. the only way a hyperloop is getting built is if it somehow includes a rider to invade a neighbouring country.
the only real reason companies even thought of doing work with the hyperloop is to do what companies do: suckle at the taxpayer teat. You start by investing in a renewable effort, secure grants and loans, develop a few proof of concept ideas, sell out to a capital management firm, and then declare bankruptcy.
Good people go to bed earlier.
Larry Niven's book World Out of Time has a "hyperloop" system in it. And I can't help but think other SF writers may have come up with something similar before that.
The notion that Musk came up with this 'idea' is ludicrous.
Imagine a section of tube going splitting away from the main network. It has an airlock shortly after the split, then gently curves up a tunnel through a mountain, and exits at a rather steep angle upwards. Then there's a quick-acting airlock at the opening.
A special train is loaded - a rocket adapted to travel through these tubes. It speeds up to the regular Mach 1 in the "civilian" section of the tunnel, then goes down the branch and gains another 2-3 Mach. The airlock at the end opens right before the rocket reaches it, then the hyperloop propulsion module drops on a parachute while the rocket ignites its engines. We've just shaved off first 1.5km/s out of the required 9 or so needed to reach orbit - and with the tyranny of rocket equation, that's quite a bit of savings!
45 5F E1 04 22 CA 29 C4 93 3F 95 05 2B 79 2A B2
a pipe dream..
I'm probably being Toronto, Canada
Can I be Peculiar, Missouri?
systemd is Roko's Basilisk.
The author doesn't know what G-forces are, that's all. They were trying to say that the person isn't exposed to a vacuum.
I hate to bring up our imminent arrest during your crazy time, but we gotta move.
"One thousand(sic) of atmospheric pressure" is not "pretty much as good as a "vacuum". Hard vacuums operate at around a trillionth of atmospheric pressure. At a thousandth of atmospheric pressure, even if you weren't in a tube you'd face relevant wind resistance at those sorts of speeds.
My original and subsequent comments have not been about the propulsion, suspension or air resistance; they have been about the cost and challenge of building the tube. No, I have not read the concept design document (we are not the design committee here), but I have got the point that it is in a tube kept at a near vacuum.
From the structural point of view it does not matter whether the internal absolute pressure (I'm trying hard to avoid the word "vacuum" as it seems to give issues) is a millibar, microbar, 10 millibars, 100 millibars or even a perfect vacuum - the structural design of that tube will be the same.
No it will not be as simple or cheap as an oil pipeline.
Oil pipelines have internal pressure (ie above atmospheric) which makes them structurally simpler because the pipe walls are in tension - which most structural material is very efficient at holding. OTOH, the Hyperloop tube walls will be in compression so there is the additional failure mode of wall buckling to consider - unstable implosion of the pipe in other words. With a tube 4m diameter (I got that from Wikipedia too) this is likely to be the dominant structural consideration. To avoid implosion buckling, steel walls will need to be either uneconomically thick, or will need to be copiously re-inforced with circumferential flanges and longitudinal ribs - unlike oil pipelines. One solution would be to make the tube of concrete which is far cheaper than steel, so the walls could be thick and hence more stable against implosion buckling - but then there would be far more self-weight to consider, negating the "advantage" of light pods/capsules/cars/whatever-they-are-called.
A further difference from oil pipelines is that the latter can make relatively abrupt changes of direction. Eg, to cross a small valley, the oil pipes can simply dive down into it and rise up the far side, on relatively low and normally-spaced pedestals all the way. The Hyperloop could not do this - it would need a high viaduct like any conventional railway - in fact it would be far fussier than a conventional railway to keep the lateral and vertical accelerations within passenger tolerance at its high speed. Maybe the landscape is featureless where the Hyperloop is going (I don't know); otherwise some very serious civil engineering is going to be required on its route.