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Hyperloop: Pipes of Fancy

economist.com

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Re: Hyperloop: Pipes of Fancy

#241

Post by [deleted] »

reitzensteinm wrote: post #57
nickik wrote: post #52

Earlier quoted context omitted.

They were actually not. And in the cases tax payer funding was involved it was not some sort of blank check. SpaceX got to orbit and was financed privately. Only once SpaceX had proven that capability, they were selected by the government to deliver cargo to ISS. SpaceX had to submit a competitive bid and was selected because they were the cheapest. SpaceX has fully executed on this contract and it was by far cheaper…

> Its important to not that GM, Ford and Fiat-Chrysler received far, far, far more resources in the 2008-2012 timeframe and most of that has unlike Tesla not been payed back Most has not been paid back? What figures are you using for this? My understanding is that the bailout was ~$80bn, but the final cost to the government was approximately $9bn. When people complain about Tesla being taxpayer funded, they're genera…

[deleted]

Re: Hyperloop: Pipes of Fancy

#242

Post by bildung »

nickik wrote: post #52
kevingadd wrote: post #31

Earlier quoted context omitted.

Are you asserting the space and electric ventures were not funded by taxpayers?

They were actually not. And in the cases tax payer funding was involved it was not some sort of blank check. SpaceX got to orbit and was financed privately. Only once SpaceX had proven that capability, they were selected by the government to deliver cargo to ISS. SpaceX had to submit a competitive bid and was selected because they were the cheapest. SpaceX has fully executed on this contract and it was by far cheaper…

Teslas total subsidies divided by total amount of cars produced: $2500 per car. These, to my knowledge, do not include the various EV incentives the buyers get.

GM total subsidies divided by total amount of cars produced from 2010 onwards (couldn't find an all-times number): $77 per car.

Subsidies from https://subsidytracker.goodjobsfirst.org/ GM cars from statista, Tesla numbers from wikipedia.

Re: Hyperloop: Pipes of Fancy

#243

Post by yodelshady »

For "short" (For longer journeys, I'm not sure there's a technical case for hyperloop over a plane even with zero land cost - planes at altitude are good at what they do. The challenge a plane has in enabling those journeys is that, whilst a plane doesn't need much land in total, it needs an awful lot at the terminus. So it's a last ten miles, not a last mile. However, a good shuttle service can solve that.

Re: Hyperloop: Pipes of Fancy

#244

Post by johnwalkr »

This is such a joke. I remember when it was first described, I predicted that it would do nothing but derail legitimate rail projects, and that's exactly what's happened in California city councils. People have been sold the idea of taking their car on the train like a ferry, for $5 instead of proper public transit, and it will never happen.

Vacuum equipment is notoriously difficult to maintain, especially sealing of moving parts. It was proposed to be cheap in part because you "just" make let the tube thermally expand and contract at the stations, rather than at regular intervals like rail. Based on the distances proposed, at California temperatures, you'd need roughly +/-20m of expansion capability, at each station. And you need this at the point where you are sealing things, and starting/stopping cars, having people move in and out (well, not many people because the capacity is a joke), and cleaning up vomit. To the safety standards for transportation. Plus all the same problems a normal train has, like getting right-of-way. Good luck with that.

One of the points in the proposal was "assuming 2.5G is an acceptable acceleration..." 2.5-3G is typical of a roller coaster, although the more intense one go to 5G or so.

Should have never made if off the napkin.

Re: Hyperloop: Pipes of Fancy

#245

Post by Skye »

_ph_ wrote: post #225
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.

I am disagreeing with the article. Of course, when designing/selling new train systems, a lot of showmanship and gadgetery are involved, but there are real shortcomings with current train systems which cause people to develop new technologies. First of all: trains are great, there are many places where they perform admirably. Many cities have a great subway network, countries like France, Japan, Taiwan and now China…

I have a few nitpicks...

Making train tunnels cheaper by making them smaller is not a new idea. it is a very old idea. Have a look at the deep level tube lines of the London underground. In some ways, we regret having trains that small since it reduces capacity and makes it nigh impossible to air condition.

It's possible to make normal trains go over existing roads, elevated rail is also a very old thing, a lot of it did get taken down though.

Re: Hyperloop: Pipes of Fancy

#246

Post by johnwalkr »

sudosysgen wrote: post #110
captainbland wrote: post #85

Earlier quoted context omitted.

It may not be totally evacuated but the pressure difference between it and the outside world is still supposed to be very large isn't it? And if you want a hyperloop that actually goes anywhere that's going to represent quite a large volume of low pressure space that you need to create and maintain. Surely this has to be quite energy intensive and generally difficult to maintain, especially since you have to get peop…

Another thing, is that anyone that punches a hole big enough in the tube basically transforms half of the hyperloop into a bomb. Energy = pressure * volume. That's a lot of energy smashing through a hyperloop capsule. Basically, imagine if 3% of the tube was filled with pipe bombs, but in reverse.

The tube would need egress points, interfaces to stations. I think the difficulty of building one tube between stations is like building a 100km long airplane fuselage. But any proposal is little more than "'just' build a tube!"

Re: Hyperloop: Pipes of Fancy

#247

Post by johnwalkr »

riffic wrote: post #65
jeffreyrogers wrote: post #5

Hyperloop has sex appeal, but it seems like Maglev or just plain old high speed rail makes more sense from an economics perspective. I can't imagine it's cheap to keep a tube evacuated. Either way, it seems good to try and build these sort of high-tech industries in the US.

common misconception. Hyperloop tubes were never meant to be fully evacuated, they operate at pressure differentials with air bearings (imagine a cylindrical air hockey table).

I recall at the time it was first proposed, Elon Musk said 0.1kPa which agrees with another comment stating 1 millibar. At the time, criticism comparing it to the old vactrain idea was dismissed as "but this tube is not fully evacuated". But it's about the same value that was proposed by vactrain, and is 99.9% evacuated.

Re: Hyperloop: Pipes of Fancy

#248

Post by johnwalkr »

masswerk wrote: post #88

What I'm failing to understand about the Hyperloop concept (apart from all the issues with thermal expansion, maintaining a near vacuum, safety consideration and passenger capacity): In real life tracks will have to include curves, as there's already terrain, existing buildings, etc. Trains have to lean into curves, just like motorbikes. With high speeds, anything exceeding a more traditional maglev train, the angles…

No problem, 2.5G was mentioned as an acceptable value for experienced acceleration. Do you like roller coasters?

Re: Hyperloop: Pipes of Fancy

#249

Post by agumonkey »

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…

Call me pro tesla if you will but I think you're underestimating the influence Tesla has had and is having on the whole planet. Few years ago they were a ridicule curiosity. Now electric vehicles are everywhere, trucks are on the way.

Re: Hyperloop: Pipes of Fancy

#250

Post by marvin »

The_Double wrote: post #214
sudosysgen wrote: post #109

Earlier quoted context omitted.

What do you do when a terrorist shoots a hyperloop tube causing a pressure wave that will kill everyone inside?

What do you do when a terrorist places a derailing device [0] on a piece of rail track that will harm and potentially kill many people inside? [0]: https://en.wikipedia.org/wiki/Derail

You never ever build railroads again, obviously, and deride everyone that plans building them.
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