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Hyperloop

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Re: Hyperloop

#591

Post by jarek »

dllthomas wrote: post #527
abruzzi wrote: post #317

Earlier quoted context omitted.

The problem is that, at least with the CA high speed rail system, the design is all theoretical at the moment. It may be a brilliant idea, but but moving from the core ideas in the document to actual working, build-able products, can be a slow process. And given the state of where CA is on their project, that may not put them on the same window.

The R&D can't happen in government, but in some ways that's better - government projects are slower than this needs to be. What we need is for someone(s?) with deep pockets to bank-roll prototypes &c.

Sounds vaguely like maglev a couple of decades ago. It too was a neat idea on paper.

Re: Hyperloop

#592

Post by HCIdivision17 »

shabble wrote: post #559
Balgair wrote: post #413

Earlier quoted context omitted.

I used to work with a system of about 1m^3, 2 little mechanical pumps would get you to 10E-6 atm or so. A turbo pump got you down to 10E-9 or there abouts. The door on the thing was about 2.5 feet in diameter, with a big ol' O-ring that would get twisted and tangled all the time (we broke it once, gorilla glue worked just fine to fix it). I also second the great sound they made. It was like 2 very angry horses going…

I imagine you might be able to locate flaws with a custom capsule along the lines of a pipeline pig[1]. It would be exceptionally hard to actually fix it from the inside whilst travelling, so you either need to do it from the outside (which requires site access and elevation gear), or bypass/shut down the tube and fix internally. [1] https://en.wikipedia.org/wiki/Pigging#Intelligent_pigging

As Balgair notes, you can get away with a lot on the short run, but leaks are notoriously difficult to patch up. Vacuum leaks are super hard to detect at these pressure ranges, where you're lucky to hear or feel them at all. More than likely, your only indication is to leak helium into the system on purpose and use a mass selector on the outside to 'sniff' for ambient helium (which is extremely rare normally). It's terribly slow and time consuming. You can always take the short cut and just sorta gunk up the leak to mitigate it, but eventually it'll wear out. Vacuum welds are far better, but also take a lot of skill to perform on the spot: any sort of crevasse will act like a leak (albeit a small one - at these pressures it probably won't matter), so the bead needs to be nigh perfect.

Or you just slam another plate on the outside, glue/weld it up and just sorta not worry about it. Heavy pumping covers a multitude of leaks.

Re: Hyperloop

#593

Post by [deleted] »

MikeCapone wrote: post #573
Aloisius wrote: post #560

Earlier quoted context omitted.

If ALL Musk does with the Hyperloop announcement is shed more light on the potential debacle that is to be our $70b+ high-speed rail in California, we owe him a debt of gratitude. Really? Because it looks like this is an attempt to derail CA HSR using a proposal for an experimental technology that offers a fraction of what CA HSR does, but is potentially faster. CA HSR replaces/upgrades two metropolitan rail systems…

> take into account electrification costs (because it does get cloudy) Did Musk say his Hyperloop wouldn't be tied to the grid?

[deleted]

Re: Hyperloop

#594

Post by asmithmd1 »

yk wrote: post #540
asmithmd1 wrote: post #291

I see just a little bit of hand-waving with how to deal with the 300 psi and 1000 degree F air. He says they will cool it with on-board water and storing the steam (I don't see a pressure here)in the vehicle. Given the tight space, will any kind of thermal insulation breakthrough be needed?

Probably not, the pressure and thus the density of the air is really low and therefore it simply does not have the energy density needed to cause problems.

The almost vacuum at the front of the pod is compressed and piped out the back and to the air bearings. After it is compressed it is 1000 deg. F and 300 psi. That sounds pretty energetic to me

Re: Hyperloop

#595

Post by krasin »

uptown wrote: post #228

Really interesting proposal. How do you maintain the tube when something needs repair? You need to shut the whole system down, don't you?

Fair question. I would build 3 tubes instead of 2. That would help with repairs as well as with handling asymmetry in demand (for example, if more people want SFO->LA in mornings and LA->SFO in evenings)

Re: Hyperloop

#596

Post by bobsil1 »

newbie12 wrote: post #567
purplelobster wrote: post #311

Earlier quoted context omitted.

I hope you're right, but in reality most people haven't even heard of Elon Musk. I've had to explain to many highly educated people what he has done, what SpaceX is, what Tesla is etc. While he's been rather successful so far, he's not in the clear when it comes to either of his companies right now, he's not exactly at the Gates level of success yet. I'm rooting for him though, he has the potential to be one of the m…

Musk is not financially Gates but he's already had a greater impact. PayPal, Telsa, SpaceX, and even that Solar company could easily be more important than creating the most successful PC operating system. The PC boom would have happened without Gates but Musk is pioneering entirely new business categories.

Not only new categories, but technically sexy ones. These aren't Intuit. In fact they're quite far from Zip2/PayPal.

Re: Hyperloop

#597

Post by [deleted] »

NoPiece wrote: post #579
ibudiallo wrote: post #449

Earlier quoted context omitted.

I live in los angeles and the proposed price is cheaper than taking a cab from the LAX to my place (4 miles). So no, this is not to help rich americans.

There is a private bus service the runs between LA and SF for $40, which is probably less than the cab fare to the airport, or what a high speed rail ticket will end up costing. http://www.lowfarebus.com/

[deleted]

Re: Hyperloop

#598

Post by dmfdmf »

Best comment on reddit so far "this is a pipe dream"

* I don't think the Hyperloop is viable and I hope they kill the $100B High Speed Rail (HSR) project before it ruins the SF Peninsula and budgets across the state.

* Setting aside the $100B HSR cost (yes, I know current estimates are $70B but it was sold at $10B and will easily exceed $100B if/when completed) the operating costs will have to be subsidized for every minute of its existence just like every other govt boondoggle. This is a white elephant and, in case you weren't paying attention, California and most cites are or soon will be bankrupt. We can't afford this, cut our losses now.

* If I was made Bay Area/CA public transportation csar (with suitable budget and dictatorial powers) my first step would be to extend BART through San Jose so it actually loops the bay and (finally) complete BART. (I am old enough to recall that that was the original design)

* I do think a high speed rail connection SF/LA is economically viable but would need to do research and crunch numbers while finishing BART. I would move the SJC airport south (with a BART extension) to Morgan Hill/South San Jose and build the connection from there to LA.

* From SJ to LA I would confiscate I5, leave two lanes for truckers and local traffic but build a high speed (300MPH) car/ferry train system so you could be blasted to LA in a little over an hour and have your car there when you arrive. Home by dinner.

* I would build a nuclear plant somewhere halfway between LA and SF on I5 so my trains would not have to use diesel fuel (too smoggy) or solar (too expensive).

Nothing here is any less fanciful than Musk's musings and far, far more practical.

Re: Hyperloop

#599

Post by enraged_camel »

robomartin wrote: post #572

None of this is to say that Hyperloop is a bad idea. The idea sounds very interesting and I'd rather spend sixty billion building a Hyperloop --even if it fails-- than the ridiculous California high speed rail project. Cost is probably off by an order of magnitude, if not more. Why? Unions and other groups. Building anything in this country costs massively more (and takes significantly longer) than one could imagine…

I'm with you that Musk seems to have ignored the human factor when estimating the cost or even the feasibility of the project.

But think about how many aspects of our lives it would revolutionize. Simple example: can you imagine what would happen to the SF real estate market if it suddenly had to compete with the LA real estate market? If talented people who live in LA could suddenly commute to and from companies in SF?

And that's just real estate.

Re: Hyperloop

#600

Post by sillysaurus »

krschultz wrote: post #569
sillysaurus wrote: post #528

Earlier quoted context omitted.

Offtopic, but please consider writing some blog posts or articles about your experiences working on nuclear submarines. That just sounds so cool, and while the work is probably dull, I'd nonetheless be fascinated to read some detailed stories.

Unfortunately I walk a very fine line about what is sensitive and what is not. I really couldn't go any deeper than what I posted here.

Well, is it cool?
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