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Elon Musk and the Hyperloop
- Maakuth 14y agoHe also recently said it's "a cross between a Concorde and a rail gun". That would at least enforce the maglev principle Jacques envisioned. It wouldn't be quite a Concorde in the pressurized tube though. But it's not impossibly far away from that concept, maybe Musk deliberately described it in a bit mysterious fashion. Time will tell.
- coenhyde 14y agoMaybe "Concorde" was just his way of saying it's fast and it transports people.
- mseebach2 14y ago"Rail gun" could illustrate the way carriages are added to and remove from the loop.
- lutusp 14y agoIn the technical literature, the term "rail gun/railgun" is strongly associated with electromagnetic propulsion methods: http://en.wikipedia.org/wiki/Railgun http://en.wikipedia.org/wiki/Railgun
- mseebach2 14y agoAh, I was thinking of a Gatling gun (http://en.wikipedia.org/wiki/Rotary_cannon http://en.wikipedia.org/wiki/Rotary_cannon), not a rail gun. The concept of rotary tubes seemed to mesh with OP's vision.
- manmal 14y agoOr a continuous maglev force (as the OP wrote) for the entire track, augmented with air pressure to store acceleration energy in the system for the other trains.
- easytiger 14y ago> it leaves when you arrive Its just maglev trains with some novel enclosed design with carriage dissociation? A bit like this chinese train concept that has drop off/pick up of carriages:* *http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&ved=0CDAQtwIwAg&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DOh5W_-_WFvc&ei=HqOsUKvVDY-N0wWBwIHgBQ&usg=AFQjCNGf6Q1M3GPYfRcjfdJ_4akLaHyulQ&sig2=-aik_mpaj0IlD9nBjTmuEw http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s...
- dandelany 14y agoHow much air pressure and track length would you need to accelerate a craft like this to supersonic speeds? ponders. Come to think of it, would that even be physically possible? My understanding of the "sonic boom" phenomenon is that it involves the craft breaking through a zone of high air pressure that has accumulated in front of it... Surely this wouldn't be possible if the pressure itself were propelling the craft. My (uninformed) guess would be that supersonic speeds are attainable with this kind of system, but probably unfeasible, and crafts probably wouldn't experience the sonic boom phenomenon.
- qxcv 14y agoHe also said that there aren't any rails and it runs on the ground. At the moment, we have a Concorde without wings[0] (a lifting body Concorde, perhaps?) crossed with a railgun without rails. Sounds like vaporware. [0]: It could still have wings but operate under ground effect, though it seems that it would be difficult to keep your leading edge intact travelling just above a hard surface "twice as fast as an airliner". "Twice as fast as an airliner" is Mach 0.85 * 2 = Mach 1.7 at FL360, which translates into Mach 1.5 at sea level. One useful thing we learn from this is that this system will basically have to be propelled by compressed air or electromagnetic force, since props don't work over Mach 1 and we don't have electric turbines.
- lnanek2 14y agoHmm, well I guess roads are cheaper than rails (i.e. rails along the entire route of the trip, not speed up rails like in a rail gun). And powering something from fixed locations (guns) is cheaper than bringing your engine with you. So maybe it is like a train, one person per, but it runs on cheap road like track, and it's propulsion is provided by fixed stations. If each track was a straight run from station to station you could just ditch the wheels and whatnot and fire the thing between stations along the ground. There's no way it could move so fast and still use car roads, unfortunately, so it will still have problems buying track space or building tunnels or building elevated paths. Too bad it runs on the ground.
- eru 14y ago> Hmm, well I guess roads are cheaper than rails [...] We could look that up. But considering that roads and rails the world over are often build by governments or government owned corporations, I expect Elon Musk to have found a much cheaper way to build his infrastructure.
- nnq 14y ago...the first bit of Hyperloop speculation that actually makes sense and seems plausible ...though the price will this will likely go up because it's new and untested technology and it has to be SAFE: the price difference between "doing something" and "doing something safely" can be orders of magnitude (think airplane safety) so I wouldn't rush to invest in it though...
- manmal 14y agoThe good thing is, this kind of system can be well tested before entering the market, because it does not rely on human intervention. Meaning, you test exactly the conditions you will always have.
- alexandros 14y agoAs with SpaceX I think Musk would solve this by designing for humans but testing with cargo.
- pauljburke 14y agoI'm aware this is not adding much to the discussion but I couldn't shift the intro to futurama out of my head while reading the post.
- minikomi 14y agoInteresting.. What if if gets shot one direction, presurizing something, which it uses to shoot back the other direction waiting for passenger SF [||| <> - - - - - - - - - - - - - - - ] LA pressurized --> pretty spaced out "stuff" SF [-| - |- |- |- <>-| - |- |- -| - |- |- ] LA in transit.. SF [ - - - - - - - - - - - - - - - <> ||| ] LA <- presurized for return
- bahularora 14y agosounds interesting,but this wont fit well with "it leaves when you arrive". I always imagined Hyperloop as carriages pushed by a plasma armature, in a rail gun loop. just like a plasma-rail gun.
- leoedin 14y agoJust like everything else in life the system would be subject to the laws of thermodynamics. The act of pressurising air would heat it up, and heat loss would mean that it wouldn't be fully reversible. I suspect that a fully evacuated system using magnetic propulsion and energy recovery would be more efficient - the turbulent nature of air and the low-quality nature of heat energy would probably work against you to make a pneumatic spring fairly inefficient.
- aptwebapps 14y agoI don't think there's much doubt that an evacuated tube would be very efficient. Not only that, but you could go much faster. Jacques has rejected that hypothesis for other reasons.
- dllthomas 14y ago"Jacques has rejected that hypothesis for other reasons." Specifically, due to a specific statement that it is not an evacuated tube.
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- Jabbles 14y agoSo it's what they have in Futurama? http://goo.gl/uEmNW http://goo.gl/uEmNW I'm not really sure how it "can't crash", nor how there aren't any "rails" (or things that look suspiciously like rails).
- daniel-cussen 14y agoYou know they were planning on building this in Manhattan?
- simondlr 14y agoAnother point to mention is that it is also solar-powered.
- jcfrei 14y agosorry for being kind of a buzz kill - but I'd rather see elon musk venture away from traditional engineering ventures and going into life sciences. the hyperloop seems like an interesting concept, but I don't really see where it fits in, given that his electrical revolution of individual transportation succeeds. Very densely populated areas like new york are already reasonably served by a metro - scaling that system might be cheaper and equally effective as the hyperloop described by jacques mattheij. building new tunnels is very expensive and would probably account for most of the costs in this endeavor. additionally finding spare space in dense cities to construct such a hyperloop might be very difficult besides existing sewer systems and electrical lines, offsetting the benefits of the hyperloop (after all this would require massive public funding) expanding this system to long distances would be really interesting, however even more expensive, given the need to construct long tunnels or tubes.
- jpatokal 14y agoWhatever the Hyperloop is, it's a long-distance transport mechanism, not a replacement for the subway -- he said so much himself: http://inhabitat.com/elon-musks-hyperloop-train-could-travel-from-los-angeles-to-san-francisco-in-30-minutes-flat/ http://inhabitat.com/elon-musks-hyperloop-train-could-travel... Techwise, I still think the Lofstrom loop theory sounds the most likely: http://en.wikipedia.org/wiki/Launch_loop http://en.wikipedia.org/wiki/Launch_loop
- danpalmer 14y agoMusk has said that he doesn't want to be involved in Hyperloop, and after publishing it next month will just leave it up to others to build/test/commercialise/etc. I guess he doesn't have much time being two CEOs and a CTO.
- aik 14y agoI'm curious what your overall point is? The purpose of new innovations is to improve something. It's possible that in the very short term something like wouldn't be the most cost effective thing, however it's not about the very short term, but rather about the potential. In most existing transportation systems, the potential of the system without large changes has probably mostly been realized. The potential of something like this may be much larger, which is why it would be worthwhile.
- guynamedloren 14y agoMusk has also noted that the system would be "protected from the elements"... Perhaps he meant the 'pods' inside the tube would be protected.
- 6ren 14y agoRe: "no rails" - perhaps it reduces friction by not touching the ground, via a combination of a railgun propulsion + airfoil. Thus, not needing continuous maglev for levitation. Also explains the "concord" comparison.
- Swannie 14y agoI'm thinking: - Air based, but near the ground - The vehicle is concord shaped - Vehicle is launched into the air via rail gun (like a fighter jet on a ship: http://en.wikipedia.org/wiki/Electromagnetic_Aircraft_Launch_System http://en.wikipedia.org/wiki/Electromagnetic_Aircraft_Launch...) - Lots of boosting strips a few KMs apart. - Based on the rail gun concept, the same "boosting" strip could also slow down or speed up a vehicle - It removes the need for anything between the stations except open space. - Minimal on-vehicle propulsion - otherwise I imagine the constant accelerate/decelerate would be a little unbearable for human flight - Failure mode of the vehicle is to glide to a landing (though could magnetic eddy currents be used for breaking in a rail gun with minimal/no current?) - The loop could refer to the idea of a continual loop of boosters, in opposite directions, removing the need for large "turn around" stations at either end
- meric 14y agoAlmost sounds like a bigger version of http://shweeb.com http://shweeb.com
- deleted 14y ago[deleted]
- kapitalx 14y agoto go between LA and SF in 30 minutes you'll need to approach the speed of sound. Certainly self driving cars don't fit that category. Also Musk talked about it as a 5th mode of transportation, not sure if cars would cut it.
- graeham 14y ago“Cheaper than high speed rail” - why is high speed rail expensive? I believe because precision contact between rail and wheel is required. How would this be done cheaper in a tunnel? One issue with a tunnel is that even if the air and carriages are moving at the same speed, there is still drag or friction between the air and the wall of the tunnel by Poissiulle's law. At the proposed speeds (~300km/h) and distances (600km), this becomes a lot, and higher pressures (if my quick calculations are right) lead to higher energy requirements through higher air density. In a vacuum, this friction would not exist. I can post my calcs if there is interest - I used a Moody chart and Darcy's friction equation, and ended up with an energy requirement that there would have to be ~80 million carriages going each way to be as efficient as a Telsa roadster, and neglecting any other losses.
- jacquesm 14y ago600 kilometers / 80 million carriages gives me 7.5 mm per carriage length so I think there is a bit of a problem with that calculation. The limiting case is when the whole tube is full of carriages, say they're 4 meters long that would mean there are a maximum of 150,000 carriages in that 600 Km long tube at absolute maximum capacity, something that you probably should not want to get close to. More realistically, a regular roadway has a spacing of about 30 meters per vehicle at 60 Mph, you might be able to pack them in that tight in a tube like this but that's still pretty tight and leaves very little room for error when shifting carriages in and out of the loop. At that spacing you could stuff (600,000 / 34) = 17650 carriages in (none of those assembled into impromptu trains, which of course would increase the density). If we assume train like assemblies of 10 cars with 30 meter spacing you'd be looking at a 40 meter train + spacing is 70 meters, or 8500 trains, so 85000 carriages. Those would then be pushing a column of of air 30 meters long ahead of them.
- graeham 14y agoI was trying to compare the energy required to overcome friction of the air against the tunnel to driving the route conventionally. 80 million is an excessive number to expect want to travel at one time, which implies that driving is much more efficient from an energy required perspective.
- topbanana 14y agoI don't think the tunnel would need to be pressurised. If the air moved at the same speed as the train, no resistance would be met.
- jacquesm 14y agoThat's what I meant by using the carriages as the impellers, so effectively they push against the air in front of them up to the next carriage, which pulls on this air because it leaves a partial vacuum behind it. So there is no external source of pressure, it's just the carriages moving and 'drafting' in each others wake. There will still be resistance though, both from the walls as well as leakage between the carriage and the walls (there can't be a really good seal there or the friction between the carriage and the wall would become too large, and since the wall is stationary and the carriage is moving very fast this friction is likely sizeable).
- loceng 14y agoDo you know the speed differences that could occur in a tunnel system like this, versus an "open" on-ground maglev system?
- Tichy 14y agoHowever, somehow using pressurized tubes for mail failed in the long run. I find those very fascinating, and apparently once upon a time some big cities were actually connected with a lot of such pressure tubes for sending mail. But apparently they were too unreliable and ended up going into oblivion. Would be interesting if some of them could be resurrected somehow. Another idea for improving transport: with modern technology better routing should be possible. Instead of all people boarding the same train that stops at every station, why not only board a carriage that goes directly to your destination? That could save a lot of time, I think.
- kokey 14y agoI think your second idea is closer to what I think matches the things known about Hyperloop. I am convinced that electric (or hybrid) cars that self drive along beacons is the obvious next step in human urban transportation. These follow loops, like bus routes, that will pick you up when you get to a location along the loop since you have requested it (e.g. phone app) and drop you off at say a station, or another loop intersection where you can get into another loop vehicle, a loop bus or train at a scheduled and managed time. It can send the right size and amount of vehicles out of the depot into loop depending on how many people want to get on during a cycle, it can park the electric vehicles to charge at the right time. To the user it's a matter of saying 'I want to get to the conference at 9am' and the system will tell him what time a car will pick him up at his chosen pickup point.
- Tichy 14y agoAbsolutely, and since Musk has an electric car company, something along those lines might be quite realistic. For electric cars used in that way, charging would not be an issue, as it would not be the burden of private car owners. I just had another thought, although maybe a bit ridiculous: the main issue with "public cars" to me seems to me hygienic, how to keep them clean. What if in the future instead of owning whole cars, you only own a capsule with seats that can be picked up by transporters? I'd still prefer a world where parked car things are completely gone, but such capsules might still save a lot of space in the meantime.
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- danpalmer 14y agoI have a problem with the quote "no rails required" because I would interpret that in a general sense, i.e. a Car does not need rails. To me, a tube just sounds like a special kind of rail. However, all the most plausible theories I have heard so far, and my own possibility, all rely on some sort of (although not traditional) rails.
- monk_e_boy 14y agoProblems: Digging a tunnel takes years and cost billions (see London underground new tunnel http://www.bbc.co.uk/news/business-16320945 http://www.bbc.co.uk/news/business-16320945) Making the tunnel fit the carrage = no room for emergency Security (terrorists + bomb = nightmare at speed of sound) Windows? What would you look at? If he thinking of just goods (not people) then some of these problems are much simpler - the tunnel could be less than 1m in radius. My wild idea is that he is going to us a rail gun to fire drones up a couple of KM into the air, these then glide down to mini airports. Replace freight railroads.
- Volpe 14y agoTerrorists + bomb = nightmare (regardless of speed). By this logic Planes are a bad idea too (no room for emergency, high speed, tiny windows with nothing to look at)...
- jacquesm 14y agoYou don't have to dig. Just place the metal shell on posts like an oil pipeline.
- Swannie 14y agoPeople don't like windmills because they are "ugly". They don't like power-lines in the country side. They certainly wouldn't like a 2.5M+ diameter tube running around. In London, 56% (IIRC) of the "Underground" is above ground, much of that above road level.
- jacquesm 14y agoIt beats looking at a 6 laner highway! And you could burry it halfway and still have easy access.
- monk_e_boy 14y agowe have a lot of wind turbines where I live. You get a strobe sounds of wuh-wuh-wuh-wuh-wuh if you are down wind of them. They are noisy. Also, if the sunlight catches them you also get a strobe reflection off them. That is also horrible. There is a farmer who has 2 turbines up, he lives on the far side of a hill about a km away - you can still hear those whoosh-whoosh-whoosh all day long. Painful. Powerlines also run over a lot of campsites near my house, you can hear them hummmmmm and crackle. In the damp/rain/mist/fog you can hear a lot of crackling and humming from them. I can understand why people get angry with them. In urban areas where there is a lot of noise, I guess you wouldn't notice it so much. Off topic, but my sister worked in a place where they put the magnets into wind turbines. There was a loud crash one day, someone had a magnet on a pallet, lifted it with a forklift and drove it out to a van. Half way the magnet got sucked by another magnet (in one of the factories) and burst through the wall and the two clamped together. They never got them apart and had to take the remaining bits of the turbine apart from around them.
- shin_lao 14y agoInteresting speculation by Jacques, but I think the combination of rail run and Concorde is a rail gun that fires hypersonic motor-less capsules that glide to destination. Smaller landing zones, no air pollution, much less noise... It's also a good combination of Telsa (rail gun) and SpaceX (rockets can be seen as motorized slugs). Only limit I see with this system is that I'm not sure anyone could withstand the acceleration.
- netcan 14y agoThat's the only limit? To big guns that fire people?!
- debacle 14y agoThe nice thing about acceleration is that you only need to wait a bit longer to get to the desired velocity.
- Gravityloss 14y agoA sling would be much better for this: it's much smaller than a huge gun and also more flexible since the direction and elevation can be changed by altering the release point and axis. Centripetal acceleration is a = v^2 / r so for 300 m/s (about mach 1) speeds, for 1 gee centripetal acceleration you'd need 9 km radius.
- cpeterso 14y agoMaybe this sling is the "loop" in Hyperloop.
- dylanhassinger 14y agoI think this is it. Wrote about it here: http://dylanized.com/the-hyperloop/ http://dylanized.com/the-hyperloop/
- Gravityloss 14y agoThat makes quite a lot of sense. Air resistance could be a problem though. I guess if it was a loop, air could travel inside the tube but then you run into friction problems - it takes a lot of energy to keep the air running.
- loceng 14y agoFirst time I read it wouldn't be an evacuated tunnel. Next thought of technology it could use then then jumps to maglev-like technology; Imagine a Tesla vehicle (or others) that can hop onto a network that brings the vehicle onto a maglev system, reducing friction (and other elements wouldn't really effect it, especially if you decided to put a canopy over it) ; Anyone else realize he may have dropped a hint in this video (http://video.ft.com/v/1974478965001/Elon-Musk-from-electric-cars-to-Mars http://video.ft.com/v/1974478965001/Elon-Musk-from-electric-... ) that we might see flying cars? You'd need on-ramps, where a minimum speed is required before merging with the main line, and of course you'd only build on/off ramps at major hubs. The only issue I see being you're not using tar then, and therefore costs of raw materials would be higher, at least initially, and would likely last longer than tar. Being cheaper than highspeed rail could fit into this equation because its the vehicle owners paying for the vehicle, and no trains are being build for it - so actual money going into the system, the synergies that would exist, might be greater - though putting it how he does is creating lots of attention. :) Maybe the hyperloop refers to a an on/off ramping system, where you get accelerated to a certain speed... Fun speculating. And time for tea and breakfast.
- benzofuran 14y agoAll great points, but I will point out that the major cost item on high speed (or any rail for that matter) is the rail itself. The cars and locomotive are relatively cheap, but you're looking at figures of $1M+ USD per mile of track.
- netcan 14y agoIf/when self-driving cars succeed in being ready for public consumption, I think a huge opening for revolutions in transportation gets opened up. - If you can call your car, it can park farther away. Parking is one of the biggest problems with cars in urban areas. - Instead of calling of your car, you could just call a car. A self driving car and a self driving taxi are pretty similar, but one can run 24hrs and reduce the parking problem more. - Computers can do things people can't do. Once enough auto-automobiles are out there, there can be autoauto only "features". The same square footage of tarmac might be able to move cars much quicker. Maybe autoautos can handle 200km speeds. Maybe they can cooperate to make traffic smoother. Maybe they can link together like trains to overcome congestion. There is nothing quite as good as having a car to take you exactly to and from where you want to go. If self driving cars can really mix with human drivers everywhere they may have a nice smooth path to innovate on gradually. Big vision plans for revolutionizing transport are so centralized, so premeditated. edit: one more thing. self driving cars interact in an interesting way with public/mass trasport, especially if people dont own their own. It may reduce the demand by competing more directly on one hand. OTOH, it will compliment by providing the last-mile component.
- kokey 14y agoThis. Between this and delivery drones, is our nearby future of transportation.
- indiecore 14y agoI honestly don't think delivery drones are going to be a widespread thing. Too many problems that you can encounter that lose you an expensive drone that wouldn't lose you a simple high school age delivery driver.
- ricardobeat 14y agoDrones are not expensive at all (you can buy one for $300), and will only get cheaper.
- WhaleBiologist 14y ago
- sunjain 14y agoRather than self-driving cars, I see hype-loop kind of system being more effective overall(reliable, cheaper). Obviously a lot more work has been done(Google) on self-driving cars but I would secretly hope/wish that Elon really gets cracking on this thing(especially since he has to regular suffer one of the worst commutes in the world - 405 freeway in LA - especially that particular section).
- Angostura 14y agoSorry to be the pernickety one, Jacque but inyour opening sentence: "For a while now there are tantalizing hints that Elon Musk is at it again." isn't correct English since "are" is the wrong tense. Try "For a while now there have been tantalizing hints that Elon Musk is at it again" Or perhaps better: "There have been tantalizing hints that Elon Musk is at it again for a while now"
- josephagoss 14y agoIf your sorry to be that guy, perhaps send Jacques an email instead of posting on a public forum. Unless your not so sorry that you had to be 'that' guy.
- jacquesm 14y agoYou're right. Sorry to be nit-picking, but my name is spelled 'Jacques'.
- Angostura 14y agoSorry about that.
- gagan2020 14y agoLooking to me like router/hub concept in the real world called Hyperloop. You have network (pressured tunnels) with packets (packets which carry me around Hyperloop) controlled via nodes aka router/hub (locations where people could board). Brilliant.
- DanielBMarkham 14y agoSorry Jacques, I'm sticking to the suborbital maglev thing. Yeah, I know it's a long-shot, but it fits into my idea of Musk better than a giant mail tube. I'm just seeing pressurized tubes scaling. There's the same problem with the orbital sub-loop, but I'm betting Musk spent a lot of time looking at this idea as part of his Mars dream. One thing's for sure -- it's going to be a blast seeing how it all turns out!
- Tloewald 14y agoDidn't he say in the Ariane 5 is dead interview that it's a cross between a Concorde and a rail gun, so think super streamlined glider, launched by maglev, captured by maglev (recovering some energy energy on capture). High speed rail without most of the rail. The big issue would be air traffic control at launch and landing. 600 m/s (Mach 2) at 0.5g acceleration would require 36km of launch rail which is kind of a lot. But you could loop the track and reduce the acceleration to make up for centripetal forces — a 200m radius loop might be about right, and once you use a loop you can go a lot faster (and this explains the name: hypersonic loop). I suppose it might skip short distances requiring pylons or something for speed top ups and travel at lower speed.
- maxerickson 14y agoI figure it is a side by side maglev with a bunch of mass going around one of the tracks to store energy. That's assuming the mass needs to be on a second track to maintain a schedule. I guess it's probably possible to do something clever at the stations to avoid a second track.
- jusben1369 14y agoEveryone's assuming Musk has the answer and we're guessing at it. I feel like he's prompting the world to create the answer. True leadership at its finest. Define the problem, broad brush what the solution could and should be and then watch minds go to work.
- majorlazer 14y agoI don't think that this is what he is doing but this definitely crossed my mind over the past few weeks. It's pretty awesome how inspiring a person like Elon could be. A year ago, the general public and geek community didn't really talk all that much about alternative modes of transportation. Now, all because of Musk, everyone is all of a sudden trying to come with a new idea.
- dllthomas 14y agoIf that is the case, the name is clearly appropriate. Hype-er loop.
- n_coats 14y agoElon Musk > Chuck Norris
- grumblepeet 14y agoI suspect that it is a beneath the road electrical induction charging system so that cars/vehicles don't need to carry heavy batteries to travel longer distances.. On open roads, where batteries fall down on range, surely this would make sense? Combine with self drive for easy town to town driving experience.
- btilly 14y agoI think that you ALMOST have it. You've even explained the following tantalizing quote from July: I think we could actually make it self-powering if you put solar panels on it, you generate more power than you would consume in the system. There's a way to store the power so it would run 24/7 without using batteries. Yes, this is possible, absolutely. The cars in the loop store power. A lot of it. Now why do I say almost? Let's make one small modification. Let's put a lot of one way flaps in the tube so that it is easy for a puff of air to blow out, but not so easy for air to come back in. There would be leakage, but that is going to be OK. As each car comes by, it piles up air in front of it that blows out of the flaps. Then the flaps fall back, and maintains a partial vacuum. The partial vacuum is no problem for people because there is a pile of air in front of their car that can be tapped for breathing air, that can then be released backwards, where it circulates through the tube (and probably out the flap). This makes his evacuated tube comment even more of a teasing joke. No, the tube is not evacuated. Nor did you pump air out of it. But it winds up almost evacuated. However it is still fine for breathing. Now the point is that reduced air pressure inside of the tunnel significantly reduces drag caused by the air dragging on the edges of the tunnel and being pushed by the cars. This does a lot to make the whole thing massively more efficient. Elon's claim is then that it is efficient enough that it can be powered by solar panels placed on the tube. My big question is how hot it will be. There may be very little gas in the tube, but that gas will be very, very hot. Over time the cars will heat up as well. So you'd need to have the cars regularly coming in and out of the system so that they would have time to cool down. The practical difficulties in building this are immense. But I do not see any physical reason why it is impossible.
- jacquesm 14y agohey Ben, I think that the gas won't get too hot because it has all of the surface of the sheath to cool it. But that's a precarious balance, and it will need some pretty good book keeping to make sure that all the power generated on a stretch 'x' meters long gets radiated out from the tube to keep the temperature stable. As for the flaps, you're right, I didn't think that bit through, I'm not quite sure what the best solution would be there. But if that's the only thing wrong with what I sketched I'll be pretty happy.
- jws 14y agoMoving the air through the tunnel addresses the capsule drag, but now you have drag between your moving air and the tunnel wall, which depending on the distance between vehicles is going to be a larger loss. Yacht designers refer to the "wetted area" component of drag, and an entire tunnel wall is a heck of a lot of wetted area.
- jacquesm 14y agoWould it be possible to run a partial vacuum just in the space between the vehicle and the tunnel wall, for instance by having the vehicle body be slightly curved away from the wall except at the end points?
- socialist_coder 14y agoDidn't Elon also say that the Hyperloop would be buildable/achievable without having to obtain large swaths of contiguous land for the construction of the entire loop (which is next to impossible in developed countries)? How does this prediction meet that requirement? Or am I missing something? This is the quote I'm referring to: "It also can’t have a right of way issue, where people have to give up their homes." http://techcrunch.com/2012/11/19/elon-musk-with-jobs-gone-google-will-win-mobile-and-look-out-for-the-hyperloop/ http://techcrunch.com/2012/11/19/elon-musk-with-jobs-gone-go...
- jacquesm 14y agoYou are absolutely right, someone else in this thread also brought it up. I completely missed out on that requirement and indeed it seems to invalidate the whole thing. Unless there is a recycling of roads somehow. The thing that bugs me about the whole 'space' angle is that if that is the solution it is only usable between endpoints, and roads are usable for everybody (also those people living between the endpoints). You then get the same issues that you have with airports, you have to actually go to one of very few terminals in order to get on the loop. And ground transportation converging on the loop would be the bottle-neck (think highway LA - SF with only one on-ramp). So likely we're missing a huge piece of the puzzle still.
- socialist_coder 14y agoDefinitely. It's still enjoyable to read these ideas though =)
- dcosson 14y agoOne thing not mentioned here is speed. Musk has said this could go from LA to San Francisco in 30 minutes, which is an average speed of ~700 mph - slightly faster than a commercial airliner but in the same ballpark. I'm definitely not an expert in fluid dynamics, but it seems like safely maintaining that speed in a tube at atmospheric pressure would be difficult. Maybe there's some way to design the shape of the pods such that there's a very stable equilibrium keeping it away from the walls. Or you could potentially use a magnetic field to do this (similar to a tokamak) but that seems be trickier and more expensive than a mag-lev rail. An evacuated tube has the advantage of being much more stable at high speeds and avoids the issue of excess heat from repeatedly compressing and expanding the air in the tube. In any case, great read. I almost wonder if Musk has thrown this idea out half-baked just to get more people to start thinking outside the box about transportation...
- stcredzero 14y ago> Or you could potentially use a magnetic field to do this (similar to a tokamak) but that seems be trickier and more expensive than a mag-lev rail. Using Halbach arrays would do it, without any active control.
- schiffern 14y agoHow can anyone possibly suggest that this would be cheaper than high-speed rail? If you're going 1150 mph ("average speed twice as fast as a commercial jet"), the curve radius is going to be immense – 90 km to maintain <0.3 lateral g. This will constrain your right-of-way selection vastly more than the HSR project Musk scoffs at. And, of course, the skin friction on a 2.5 meter tunnel would be immense. Using a duct friction loss calculator I get 285 megawatts of loss over the entire tube. You need two tubes. At 120,000 passengers/day (HSR estimate), it would take 114 kWh per trip. That's worst than the Model S, hardly an system in which "the fundamental energy cost is so much lower" than a car. No, the "theoretically fastest way" to go from Point A to Point B is a great-circle vacuum train connecting them. A launch loop does essentially that, but exploits the vacuum above our heads instead. It just fits better. Any hyperloop theory needs to deal with supersonic speeds – LA-SF as the crow flies in 30 minutes is just under the wire for subsonic speeds. Elon said "under 30 minutes." There are mountains in the way.
- grego 14y agoUsually when comparing speeds of trains and airplanes you factor in the transit time from city center to airport + security checks etc. So the time measured is total travel time. Railway stations are already at city center, and security is less strict so time savings are considerable for the benefit of rail.
- graeham 14y agoGreat points! The lateral g load could be reduced by banking the capsule - but you still raise an important limit that even with banking would still cause an unreasonable curve radius. Launch loops are interesting. They seem to be even more difficult than tether-based space elevators, which have themselves been unable to work due to material strength:weight constraints on the tether. I'd expect the belt supporting a launch loop to have similar constraints, and the dynamic bending of the belt would raise fatigue concerns. Agree with your speed estimations and that supersonic or near- speeds have very high drag costs and complicated analysis.
- schiffern 14y ago
- mkuhn 14y agoThe Hyperloop reminds me a lot of the Swissmetro [1] project which was launched in 1974 and was intended to connect Swiss cities trough evacuated tunnels which would house maglev trains. The evacuation made the project very expensive but a lot of tests were run and a lot of the learning probably can be applied. Solving some of the problems that made the Swissmetro so expensive could lead to what the Hyperloop wants to be. [1 ]http://en.wikipedia.org/wiki/Swissmetro http://en.wikipedia.org/wiki/Swissmetro (the German language article is much more extensive: http://de.wikipedia.org/wiki/Swissmetro http://de.wikipedia.org/wiki/Swissmetro)
- robomartin 14y agoI think everyone is ignoring the elephant in the room. This is a long story, but I'll try to keep it very short. Anyone interested contact me off-list for far more details and an unfinished paper with some of my research. A couple of years ago my son and I were watching a documentary on the subject of concrete. It was very interesting. They covered a wide range of topics but one of them really started to trigger my curiosity: The Panama Canal. I don't know why, but I became very interested in the financial metrics surrounding the canal. How much does it cost to cross it? How long does it take? How many ships cross it per year? Where do they come from? Where do they go? The more I learned the more the reality of the Canal horrified me. Why? The bulk of the commercial traffic through the Canal are container ships. And these ships burn something very nasty: Bunker Fuel. This is, by almost any measure, the dirtiest fuel you could burn. it's horrible stuff. When I started to do the math I started to realize the magnitude of the problem. These ships move at about 20 miles per hour. They could go faster but there's a balance between the high cost of hydrodynamic drag and fuel costs. A trip from Shanghai to Long Beach takes about 18 days and will burn somewhere in the range of 3,600 to 7,200 metric tons of fuel. For those not comfortable visualizing units in the metric system, that's from 7,936,560 to 15,873,120 pounds. Yes, fifteen million pounds of the nastiest crap you could burn is used to bring your iPhones (conjecture) and other stuff from Shanghai to Long Beach. If my research is correct, the fleet of about 100,000 cargo ships (Yes, 100,000!!!) burns over a million metric tons of bunker fuel PER DAY. 400 million metric tons of bunker fuel per year, which is equivalent to 120 billion gallons. Can't relate to that number? Here's an interesting comparison: To get a better sense of how large this number is we can try to relate it to how many cars one could fill-up with fuel and for how long. 120 billion gallons would provide enough fuel to supply 100,000 cars (assuming a 20 gallon tank) with a full tank of gas every week...for over 1,000 years. 100,000 cars. 20 gallons per week. For a THOUSAND years. And our fleet of container ships use this in ONE YEAR. The evil, when it comes to pollution and energy dependence, isn't the much-abused light bulb; it's the elephant in the room: Ocean-going cargo ships. While our mass media chooses to focus its attention on an oil spill (because it is sensational and it serves political purposes), what is really killing our planet slowly is the transportation of iPhones, Blackberries, TV's, blenders, washers, cars, widgets and gadgets on inefficient and highly-polluting ocean-going vessels. Even the latest Gulf spill is insignificant in terms of environmental impact when compared to what 100,000 ships are doing to our environment each and every year. It is estimated that the fleet of nearly 100,000 cargo ships in the world produces over 20 million tons of Sulfur Oxides (SOx) per year. For comparison, the entire fleet of automobiles in the world (about 800 million cars) produces about 80,000 tons of the same contaminant. How about the Canal? A container ship traveling from Los Angeles to NYC through the Canal will burn about 4,500 metric tons of buker-C fuel. This amount of fuel costs approximately US $1.8 million. Canal fees would run somewhere around $300K. The trip from L.A. to NYC through the Canal runs well over two million dollars, without including handling, insurance, crew costs, amortization, maintenance, etc. That's quite a chunk of change, however, when divided by the thousands of containers a ship can move it becomes a few hundred dollars per container. How many ships go through the Canal per year? Approximately 15,000. I'll leave you to do the math. I have far more detail in my notes. What these ships are doing to our environment is simply horrific. The pollution doesn't stop at the act of burning fuel. Cargo ships are also the source of an unusual form of pollution. Ships use huge ballast tanks to stabilize themselves. These ballast tanks are filled and emptied of sea water during loading and unloading operations at port. It is through this mechanism that cargo ships are responsible for transporting harmful organisms across the world into ecosystems that cannot handle them. The introduction of non-native species into a new ecosystem can have devastating consequences. And so, from watching a simple documentary I came to the realization that, for some strange reason, we have been ignoring the most significant source of environmental pollution on our planet. And, beyond that, one of the largest --if not the largest-- consumer of petroleum products. I didn't stop at just identifying the problem. I also wanted to take a stab at a solution. I came up with something I called "The American High Speed Cargo System" (AHSCS) as a loose proposal. This would be a cargo-only, electric powered, high speed rail system. It would connect --at the very least-- both coasts and, ideally, other major US ports. The idea would be to move cargo over land from port to port at 200 miles per hour. High speed passenger trains in the US are a waste of money and that's particularly true in California (don't get me started there). Not so for high-speed cargo. The numbers are there to support it: A cargo ship spends over two million dollars to get from L.A. to NYC. Probably closer to three. Those same containers could be moved far more efficiently over land, at similar or lower costs and pollute far, far less. You are exchanging aerodynamic drag for hydrodynamic drag. Huge difference. In terms of energy costs (just the electricity), I came up with numbers in the order of $10K for a trip from L.A. to NYC. I further estimated that the system would require around 700MW of power, let's call it 1,000MW. We have 53 nuclear plants that can source 1GW each. This is a case where nuclear power might be a really good option. However, the scope of the project needs to be realized. Developing and building such a systems has the potential to generate hundreds of thousands of jobs, if not millions. It should be revenue neutral if not positive (sorry Panama). It would allow for the installation of upgraded communications and power backbones that would be synergistic to the process of building the rail system. It would also allow for the potential to install huge solar and wind-power farms to fully or partially power the system. I have not explored every angle but would like to think that, if my numbers and assumptions are right, this could be the most important project this nation could embark on. You have to think in terms of a hundred or two-hundred year scale. These ships are not going to go away unless something very significant changes. Of course, the same concept ought to be replicated across the planet. Again, if I am right, we should strive to eliminate most, if not all, container ships traversing our oceans. We are making an absolute mess out of our planet. http://news.discovery.com/tech/shipping-network-map.html http://news.discovery.com/tech/shipping-network-map.html Like I said, there's more. If interested email me off list and I can send you a copy of my notes so far. It'd be interesting to have someone go over my notes and verify my assumptions and calculations. I tried to raise the issue with politicians but, what can I say, I only have so much time to deal with morons. NOTE: I thank you for your comments. I have to ask that you do me a favor. Please refrain from making categorical statements about the relative efficiency of ships vs. a proposed high-speed electric train without having done the math yourself. Please drop me an email and I'll be more than happy to provide you with a copy of my calcs, an unfinished paper as well as links, PDF's and references. Then we can talk about the merits of the concept. I am actually very interested in having the concept, calculations and assumptions criticized. Arguing outside of a common frame of reference is rather difficult.
- anonymouz 14y agoThe starting point of the argument is kind of whacky: He claims that the sentence "It is not (an evacuated tunnel)." is somehow the same as "It is a (not evacuated) tunnel.", but he completely ignores the fact that the position of the article that he deliberately changes resolves this ambiguity! So, duh, if you change the sentence it means something different...
- XaspR8d 14y agoI agree the rearrangement of the word order is confusing, but I can also see that Musk could have been saying "it is not an evacuated tunnel". (In fact this is the default interpretation I would probably take...) Listening to the original quote could help us, but ultimately there's no way to know if he's talking about tunnels in general or just evacuated ones.
- anonymouz 14y agoBut your interpretation is much, much weaker than "a not evacuated tunnel". If it's not a tunnel, it's still not an <i>evacuated</i> tunnel. But if it's "a not evacuated tunnel", then it must be a tunnel. Edit: Actually, I think with the article "an" between the "not" and the adjective, there is no way in English grammar to interpret the "not" to negate only the adjective instead of the whole adjective+noun "evacuated tunnel". Unfortunately I'm neither a native speaker, nor a linguist, so I cannot back it up with anything but feeling for the language and the fact that this is how I always see it used ;).
- stcredzero 14y ago> Edit: Actually, I think with the article "an" between the "not" and the adjective, there is no way in English grammar to interpret the "not" to negate only the adjective instead of the whole adjective+noun "evacuated tunnel". Well, if you add another "only" before "interpret" then you'd be correct. Otherwise, it is open to interpretation either way. Panel 11: http://www.giantitp.com/comics/oots0367.html http://www.giantitp.com/comics/oots0367.html
- 14y ago
- danpalmer 14y agoI'd like to add another possibility into the mix, I think it might be based on some moving walkway concepts that have been considered for quite a few years but have never caught on or progressed passed the prototype stage. The idea is that rather than being a straight line with a sort of conveyor belt, the walkway is made of plates like an escalator, and the ends of the walkway curve off from the main body of it. This means that a user steps on to a slow moving plate, immediately goes around a corner on it, and in doing so accelerates to a much faster speed, with the opposite happening at the destination. As soon as I heard the word 'Hyperloop', this is what I thought of. It's a looped system, but with an extra dimension in a way as different sections operate at different speeds. I think this could be scaled up to be perhaps a track system that 'cars' are put onto with passengers inside, but I don't know. Is this a reasonable possibility? Maybe. ✓ Ground based ✓ Weather independent ✓ Like a railgun (if propelled with magnets) ✓ Is not a pressurised tube ✓ Leaves when you arrive ? Could hold solar panels ? Cheap ? Revolutionise the transport industry ✗ No rails - depends on your interpretation of this, one could argue that a pressurised tube is a kind of track or rail for a carriage.
- gusgordon 14y agoI remember Musk saying that its propulsion source was similar to that of a rail gun's. Sorry, can't remember where, but it was recent.
- smoyer 14y agoSeveral comments mentioned freight transport below, but not in this context. The loop you've described requires some "density" of carriages to maintain the "group inertia". One obvious way to fill gaps that are too big is to put freight cars into the loop to fill them. Very nice article.
- Gustomaximus 14y agoPeople have built systems called Atmospheric Railways that could be closed to Elon's vision than an evacuated tunnel. http://en.wikipedia.org/wiki/Atmospheric_railway http://en.wikipedia.org/wiki/Atmospheric_railway
- frankus 14y agoI think most of OP's arguments are spot on, but I think it's likely to be an elevated system installed over the center divider of the (mostly very straight and very flat) I-5 corridor. Tunneling that distance just isn't feasible at the stated cost. (I expound at greater length here: http://franking.tumblr.com/post/36241325898/my-personal-speculation-on-the-hyperloop http://franking.tumblr.com/post/36241325898/my-personal-spec...)