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Hyperloop: Pipes of Fancy

economist.com

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Re: Hyperloop: Pipes of Fancy

#301

Post by sudosysgen »

vidarh wrote: post #262
jeffreyrogers wrote: post #142

Earlier quoted context omitted.

Also, what happens if the pods leak? Seems like the air in the pods will diffuse through the tube and the people will suffocate.

As long as pod moves, there's a constant pressure build-up of air in front of it, to the point that the design includes a compressor to pump air from the front of the pods because passively preventing the buildup by letting it blow through the pod would be insufficient. So a leak would be a piffling little annoyance in comparison - there'd not be enough volume of air inside the pods to cause a problem compared to the…

That compressor is absent from every single design we've seen right now, The duct for air to go from front to back would also use up a significant amount of cabin space, and the electric-powered multi-stage high compression ratio high-speed compressor would have massive power usage, weight, and cost. Power usage that would have to be palliated via batteries, as the capsule supposedly has no contact with the tube.

Because of this, no full-scale design yet has incorporated a compressor.

Re: Hyperloop: Pipes of Fancy

#302

Post by liability »

agumonkey wrote: post #258
qayxc wrote: post #254

Earlier quoted context omitted.

It's highly debatable whether this was due to Tesla or actual legislation, though. CO² fleet restriction forced the hand of automakers, not 3% EV market share. A substantial portion of Tesla's operational income comes from CO² certificates from automakers that don't meet the CO² restrictions, by the way [1]. Also something that people tend to overlook. [1] https://www.theverge.com/2019/4/8/18300393/tesla-fiat-chrysl.…

come on, have you forgot VW recent scandal ? CO2 emission was solved partially by cheating, not making EVs

You're mistaken, VW was caught cheating nitrogen oxide emission standards in America, not CO2. There have been some allegations they may also have been cheating CO2 emissions, but that's not nearly as clear and the nitrogen oxide emissions is really what the big fuss, and arrests, were about.

Re: Hyperloop: Pipes of Fancy

#303

Post by manigandham »

qayxc wrote: post #234
manigandham wrote: post #136

The vac-train concept is from 1799. Maglev tech is decades in production. I remember a Discovery Channel show 20 years ago about trains traveling 5000mph through tunnels at the bottom of the ocean to cross continents in an hour. Hyperloop is fantastical renaming of old tech without solving any of the fundamental problems of economy, geography, energy and politics. We're capable of building incredible projects if only…

Please remind me again how a company with a market share of 0.6% [1] is changing global transportation? It's fascinating to me how people seem to vastly underestimate the actual volume of the global car market while overestimating the impact of unicorns. In order to even make a dent in the global market, getting into the double digits would be required. Even in the market "dominated" by Tesla (e.g. plug-in EVs), thei…

Market share is just the ranking of sales by brand over an arbitrary time period. It has nothing to do with innovation.

Tesla has clearly revolutionized electric vehicles to the point where they are not just viable but desirable, and are beating traditional luxury and sports manufacturers in technology and driving experience. They've moved the entire industry forward and now every major brand has committed to making electric vehicles.

I find your comparison to Apple strange since Apple has also, quite literally, changed the world with their iPhones.

Re: Hyperloop: Pipes of Fancy

#304

Post by sudosysgen »

nytgop77 wrote: post #296
sudosysgen wrote: post #123

Earlier quoted context omitted.

Even building it below ground doesn't work, they just have to punch a hole in the station while it is pressurized.

How much damage would a bullet hole actually do? If the hole stays of fixed diameter, its throughput would be small compared to the volume of the tube, so pressure would increase gradually. So, how feasible is it that hole would not increase? What hyperloop designs are there? 10 inch thick steel throughout whole length?

The designs I've seen had very thin tubes. Certainly not anywhere close to 10 inch thick steel, no. The designs I've seen had thicknesses close to or under one inch.

A 50 cal APDS bullet would punch clean through the first layer and would likely leave an inch thick hole, and would likely cause significant damage on the other side if not penetrate it outright. This is almost certainly sufficient to cause explosive pressurization, which would likely cause immediately more damage and eventually create a powerful shockwave that would destroy anything in the tube.

Of course, a bomb next to the wall would be much worse.

If it was a 10 inch thick steel tube, it would be much better, but also ten times more expensive, making it prohibitively expensive.

Re: Hyperloop: Pipes of Fancy

#305

Post by _ph_ »

ashtonkem wrote: post #291
_ph_ wrote: post #270

Earlier quoted context omitted.

Yes, he claims to have found a way to drastically reduce construction consts. First of all, reducing the tunnel diameter, as the digging speed is constrained by volume. Second, he tries to improve the technology of tunnel boring machines. With the smaller tunnels, there is the requirement for smaller vehicles. You can't run standard trains through these tunnels. For now, he is using Teslas (quite obvious choice) to d…

> It is so funny how people critisizing Musk assume, he wouldn't understand so simple connections like seats per vehicle and transit density. Well, he does keep showing renderings of public transit stations full of Teslas and not, you know, people. It's not really a big leap to say that he doesn't understand when he keeps marketing as if he doesn't understand .

Sure he does. And he probably has a reason. But it is absurd to assume he hasn't considered that "trains" allow more people in shorter ties than a single car. So you can speculate why he does as he does, but you are talking about someone sending people to space.

Re: Hyperloop: Pipes of Fancy

#306

Post by welterde »

_ph_ wrote: post #270
ashtonkem wrote: post #266

Earlier quoted context omitted.

“For higher capacities, special vehicles for those tunnels could be constructed”. Congratulations, you’ve rediscovered the subway. If Musk wants to make the argument that he’s found a way to drastically reduce subway construction cost, I’m all ears. But he should jump straight to that, rather than this ludicrous idea of zipping personal cars around under the streets; a proposal that doesn’t come anywhere close to the…

Yes, he claims to have found a way to drastically reduce construction consts. First of all, reducing the tunnel diameter, as the digging speed is constrained by volume. Second, he tries to improve the technology of tunnel boring machines. With the smaller tunnels, there is the requirement for smaller vehicles. You can't run standard trains through these tunnels. For now, he is using Teslas (quite obvious choice) to d…

If I am not mistaken the boring co test tunnels are actually slightly larger in diameter than the London tube tunnels (3.8m vs 3.6m), so you could actually run "standard" trains through those.

Re: Hyperloop: Pipes of Fancy

#307

Post by TimSchumann »

disk0 wrote: post #81
AlexandrB wrote: post #9

This is evergreen when talking about Hyperloop: http://www.cat-bus.com/2017/12/gadgetbahn/ The problems with building this have nothing to do with technology but with right-of-way, investment, and politics. If those factors were solved, we'd already have high-speed rail in places where Hyperloop has been proposed. The fact that we don't says that Hyperloop is unlikely to be feasible as well.

first time I heard that term was in donoteat01's video on the loop[0], haven't got around to reading that post till now though (thanks for the reminder) [0] Elon Musk's "Loop" - It's bad, folks https://youtu.be/4dn6ZVpJLxs

Great video, thanks for sharing it. Haven't heard of this guy before but he does a really nice breakdown.

Re: Hyperloop: Pipes of Fancy

#308

Post by Ajedi32 »

sudosysgen wrote: post #298
Ajedi32 wrote: post #288

Earlier quoted context omitted.

One car every 2 seconds sounds totally plausible. In fact, that number actually seems pretty low to me. A single lane/tunnel should be able to handle automated cars traveling at a 2-second following distance no problem, so that just leaves loading/unloading as a potential bottleneck. How many on-ramps do you think it would take to reach a capacity of 0.5 cars/second? I'm really curious as to what sort of problems you…

You need people to drive their cars safely into the intake with an average delay of two seconds, to match a very middling subway system running at a delay of 7 minutes instead of 2, assuming that every single car is filled to the brim. This is completely ridiculous. You won't be able to make people do anything with an average delay of 2 seconds, without any mistakes. The question isn't on-ramps, it's getting people t…

Ah, I see the misunderstanding here.

Nobody will be driving in these tunnels. Only fully autonomous cars running approved software will be allowed in. Those sort of problems go from "impossible" to "almost trivial" when the exact movements of every vehicle in the tunnels is being monitored and controlled by a centralized system.

Re: Hyperloop: Pipes of Fancy

#309

Post by Ajedi32 »

liability wrote: post #297
Ajedi32 wrote: post #288

Earlier quoted context omitted.

One car every 2 seconds sounds totally plausible. In fact, that number actually seems pretty low to me. A single lane/tunnel should be able to handle automated cars traveling at a 2-second following distance no problem, so that just leaves loading/unloading as a potential bottleneck. How many on-ramps do you think it would take to reach a capacity of 0.5 cars/second? I'm really curious as to what sort of problems you…

How many amusement parks can load a ride car once every two seconds? Even continuously moving ski lifts aren't anywhere close to that and that's basically ideal conditions where the seat is delivered straight to your butt, and most users can reasonable be expected to be fit and coordinated. In the real world, people dawdle. You'd probably need dozens of loading lanes to reach .5/s, which means the stations are very l…

You mean stations like this? https://www.boringcompany.com/chicago

Re: Hyperloop: Pipes of Fancy

#310

Post by liability »

Ajedi32 wrote: post #309
liability wrote: post #297

Earlier quoted context omitted.

How many amusement parks can load a ride car once every two seconds? Even continuously moving ski lifts aren't anywhere close to that and that's basically ideal conditions where the seat is delivered straight to your butt, and most users can reasonable be expected to be fit and coordinated. In the real world, people dawdle. You'd probably need dozens of loading lanes to reach .5/s, which means the stations are very l…

You mean stations like this? https://www.boringcompany.com/chicago

The Hyperloop car proposals all seem substantially longer than a Tesla, so maybe of you stacked two or three layers in there.
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