Hyperloop Freight is a Joke • Hacker News Board

Re: Hyperloop Freight is a Joke

#31

Post by Spooky23 » Sun, Oct 30, 2016, 10:44 PM UTC

Russell91 wrote: post #2

I always come to these hyperloop criticisms expecting to find some sort of fatal flaw in the physics of energy efficient supersonic travel. But to my surprise, they instead tend to be pessimists saying things like, "You'll never get past my friends: the regulators, the government bureaucrats, and especially the lawyers!. We will drive up your costs and make you look foolish". First, no one said that designing this th…

What part of "acceleration will lead passengers to vomit all over themselves" is a bureaucratic issue?

Re: Hyperloop Freight is a Joke

#32

Post by Spooky23 » Sun, Oct 30, 2016, 10:47 PM UTC

deelowe wrote: post #25

problems wrote: post #16

Earlier quoted context omitted.

Air being drawn in results in pressure on the capsule, propelling it. Check the video out for a demo.

That demo is unrealistic. The entire end of the tube isn't going to open all at once. Instead, any realistic leak would be pretty small in comparison.

Forces of nature or other things never suddenly disrupt infrastructure.

See: http://whns.images.worldnow.com/images/22787728_SA.jpg

Re: Hyperloop Freight is a Joke

#33

Post by salimmadjd » Sun, Oct 30, 2016, 10:47 PM UTC

Of all the hyped up startups out there. I'm personally most bullish on the promise of the Hyperloop. Really Hyperloop One since they're the only one making actual progress.

The article makes some decent sounding criticism on the issue of last mile being the limiting factor. But it all reminds me of what I heard before regarding fast internet connectivity (the issue of the last mile), or why would people need personal computers. The problem with criticizing anything that can impact the future, is that we just don't know how it'll impact it.

I do know that anytime transportation or means of connecting goods or people has been changed, it has had tremendous impact in economy and how the world works.

Do we need to ship cargo at 500 MPH? With today's thinking, maybe no. But I do know by building and experimenting with Hyperloop not only we might just transform the world, in the process will probably make other accidental discoveries as an added bonus.

Re: Hyperloop Freight is a Joke

#34

Post by [deleted] » Sun, Oct 30, 2016, 10:48 PM UTC

na85 wrote: post #26

weego wrote: post #4

Earlier quoted context omitted.

I dunno... I'd feel much more comfortable if all humanities smartest technical people were trying to make the next whatsapp clone /s

Contrarily, I'd feel more comfortable if "idea guys" like Musk would leave the engineering to actual engineers.

[deleted]

Re: Hyperloop Freight is a Joke

#35

Post by notahacker » Sun, Oct 30, 2016, 10:48 PM UTC

Russell91 wrote: post #2

I always come to these hyperloop criticisms expecting to find some sort of fatal flaw in the physics of energy efficient supersonic travel. But to my surprise, they instead tend to be pessimists saying things like, "You'll never get past my friends: the regulators, the government bureaucrats, and especially the lawyers!. We will drive up your costs and make you look foolish". First, no one said that designing this th…

To be fair, Musk's original paper advocating the concept was structured as a criticism of the supposed inefficiency of rail alternatives, and was heavy on deliberate cost underestimates and light on physics. So it's not exactly unreasonable that most critiques start off with the economics.

This critique, however, raises quite specific physics-related logistical reasons why Hyperloop is a ludicrously impractical solution for most forms of freight and uneconomical for the rest. Things it doesn't mention, even implicitly, include regulation, government and lawyers. Perhaps you'd get more out of these hyperloop criticisms if you read them?

Re: Hyperloop Freight is a Joke

#36

Post by Tade0 » Sun, Oct 30, 2016, 10:49 PM UTC

cmrx64 wrote: post #17

Tade0 wrote: post #13

Here's an idea: Ditch the vacuum and instead put a mixture of 80% helium and 20% oxygen at half sea level pressure. This way you'll get a breathable atmosphere that is five times less dense than air and causes as much less drag. Imagine Teslas hurtling 155mph through these tunnels using only as much energy as if they were traveling at 85mph.

Where do you get all that helium?

I don't know, maybe from the 175 million cubic meters produced annually? For a 300km, two lane stretch you'd require around 7.5mln cubic meters - sure, that's a lot, but it's not an impossible amount.

Re: Hyperloop Freight is a Joke

#37

Post by gsnedders » Sun, Oct 30, 2016, 10:50 PM UTC

xt00 wrote: post #21

When people talk about using high speed rail in the US and talk about how it doesn't work, I think the problem is exemplified by how any rail system seems to get implemented in the US. Basically what I have seen in virtually all cities around the US that I've traveled, the train goes close to downtown or close to the airport, but not actually into the actual terminal in the airport. Or you have a fast train that drop…

There are very few high-speed lines in the world that are primarily concerned with commuting over ~50 miles; very few have stops that close together, even, if we look at anything going over ~150mph.

Re: Hyperloop Freight is a Joke

#38

Post by mangeletti » Sun, Oct 30, 2016, 10:51 PM UTC

Why not, instead of using an almost-vacuum and a separate means of propulsion, create a stream of air similar to that of bank tubes and just use that for propulsion?

Fans inside of the tube would pull air in the direction of travel, and it could be circulated or pumped in from / out to the outside at the ends. At the end of the tubes a main fan system would be the primary work horse, creating vacuum forces on the arrival end and pushing forces on the departure end.

In the last mile, the fan system could shut down and use the pressure to help stop the vehicle and even store some of the pressure to help start the system in the opposite direction later (i.e., regenerative breaking).

Re: Hyperloop Freight is a Joke

#39

Post by riffic » Sun, Oct 30, 2016, 10:52 PM UTC

problems wrote: post #12

Russell91 wrote: post #2

I always come to these hyperloop criticisms expecting to find some sort of fatal flaw in the physics of energy efficient supersonic travel. But to my surprise, they instead tend to be pessimists saying things like, "You'll never get past my friends: the regulators, the government bureaucrats, and especially the lawyers!. We will drive up your costs and make you look foolish". First, no one said that designing this th…

The best legitimate criticisms I've seen are here: https://m.youtube.com/watch?v=RNFesa01llk Basically expansion and contraction as well as just plain vulnerability of running a vacuum make it extremely difficult to do practically. The phrase he uses, "all the problems of space travel except in a gun barrel" is a pretty accurate description of the issue. Any loss of vacuum will almost guarantee loss of life. No reali…

You assume that Hyperloop's tube will run a vacuum, which is a misconception. The Hyperloop One design uses low pressure tubes which is completely different from being completely evacuated.

Re: Hyperloop Freight is a Joke

#40

Post by DannyBee » Sun, Oct 30, 2016, 10:54 PM UTC

Yawn. Freight has much bigger problems, like, in the US you have the Jones act, which essentially means freight from foreign countries gets bulk broken at a small number of ports instead of more directly moved to the ports it should go to. See, e.g., https://en.wikipedia.org/wiki/Merchant_Marine_Act_of_1920#Ef...