- cross-posted to:
- hackernews@lemmy.smeargle.fans
- hackernews@derp.foo
- cross-posted to:
- hackernews@lemmy.smeargle.fans
- hackernews@derp.foo
It’s time to be honest about Musk’s vacuum tube to nowhere
It’s time to be honest about Musk’s vacuum tube to nowhere
I don’t think you can say any of this until you actually put some money into it and check. Technology improves all the time and with it economics of such project. They didn’t really try to build any actual routes. They just tried to do some prototypes and check current feasibility. I don’t see this as a scam or a bad thing at all. No public money went into this.
A very long evacuated tube hundreds or thousands of miles long - too long to ever be actively defended - is itself fundamentally untenable. There are US states where every “welcome to ___” sign is shot up with holes. You don’t think people will take potshots at this thing?
Even if you somehow made it armoured and immune to small arms (this would be the largest armoured thing ever constructed), it would never make any sense over cutting edge high speed rail that doesn’t require an evacuated tube.
This all comes straight from first principles. To change this, any number of fantastical technologies would need to be invented (maybe the tube can be made of vibranium?).
What I always thought was the worst part about the idea is pressure equalization in the event of an eventual cabin seal failure.
Yeah I think we’ve learned all we need to know about the mega-rich “MoVe FaSt AnD bReAk ThiNgS” types and their highly pressurized people-carrying cylinders…
This is totally different, the tube is under vacuum and on land.
So the pressure difference between the vehicle and the outside is the opposite. If the vehicle fails, rather than being crushed by the pressure, the occupants explode.
It wouldn’t be that bad. Just possibly popping a lung, rupturing ear drums, and/or passing out.
Given that I always heard it being envisioned that the evacuated tube would be a tunnel, no, I don’t.
Just I’m clear on this the plan is/was to dig a large diameter tunnel underground, between cities?
As far as I know, yep. That’s how “The Boring Company” fit in to the scheme.
Better built on the moon than on California, no guns or people to mess it up
Yeah, that’s why we don’t have any thousands mile long tubes transporting dangerous substances. Oh, wait. We do! What happens when someone shoots a gun at them? They go to jail! (look up Daniel Carson Lewis of Livengood).
In your theory, why can’t the same laws protect ‘railway tubes’ that protect oil and gas pipelines? Why terrorist don’t shoot guns at pipelines all the time? Why don’t terrorist jump on high speed rail tracks and sabotage them? Where I live there’s 5000 km of high speed tracks that are not “actively defended”. There’s just a fence. Big rock could take out a train. Why do you think no one ever attacked it but everyone would be shooting at hyperloop pipes for fun?
Oil pipelines are often buried underground, they can have up to 60’’ in diameter. Hyperloop pipe is about 90’’ in diameter. It could be feasible to put it underground. I’m not saying it’s a good idea or bad idea. I’m just saying that some guy commenting on a blog is not a good reason not to try. Get enough of good engineers to work on it for a while and you will know if it’s feasible or not. That’s what they did. I think it was a good thing to try.
None of those are vacuum tubes. This is nonsense.
They leak. Literally all the time. They keep working. This won’t.
Okay well you got there eventually.
The good reason not to try is that bullet trains have proved working perfectly in other parts of the world. Sure, they would be slower than an hypothetical hyperloop but they are a working technology that would help alleviate the transportation problem.
Why invest in a project that might lead nowhere?
I’m not anti experimentation, by any means. It’s just that as the article says, the hyperloop was proposed when a bullet train was being discussed by local politicians.
Test hyperloop track was supposed to be build close to where I live, in Antequera, Andalucia, Spain. There’s a railway test center built specifically for testing new rail technologies. Since it was build decades ago nothing was really tested there because bullet trains already existed and no one had any new designs since then. The trains didn’t really change since 1980s. At the same time bullet trains still lose to planes on longer routes because they are simply too slow. Hyperloop was supposed to change this and offer rail technology that would compete with planes on long routes. It was supposed to be the next step in rail travel that would be able to compete with air travel. Now we know it wasn’t feasible but just because it’s not right for USA it doesn’t mean it’s not worth testing.
I’m assuming it’s probably technically possible, just ridiculously expensive to build and maintain, with way less throughput than a train.
Again, maybe it is but you can’t really be sure until you design it, estimate the cost, try to lower it by modifying the design and if it’s close try building some prototype to test it. People keep talking like you can evaluate design like this on a napkin. That’s just not how engineering works.
No, it’s just not viable. Just maintaining the vacuum is hard and takes a lot of energy. Keeping it from imploding onto the high speed train is also very hard.
It does not need experimenting, it is known already.
It is and always was a scam (or just simple stupidity, or both).
Yeah, I wouldn’t really trust any of that unless it came from interdisciplinary team of engineers that actually looked into it. I know that there’s a lot of bloggers and youtubers that like to shit on every new idea but they are often wrong and are simply trying to create clickbait content.
Why is a vacuum (holding a tube in compression and 10-14psi ) harder than pressure (holding the tube in tension at 200-1500 psi).
I used to work in a vacuum lab and one thing to consider is pumping efficiency drops as pressure drops. So everything leaks all the time right, and one strategy is to just pump harder.
However at low pressurers nothing is pushing the air into the pump for extraction, something like a bend can stop gas flowing around it dramatically where in high pressure the gas behind just pushes it through. So it gets more and more energetically demanding to keep pace with leaks.
Also pressuring a giant tube to multiple atmospheres also sounds like a nightmare. It’s hard enough to keep pool toys inflated :p
It’s not a total or high vacuum. It’s a partial vacuum like -10psig.
Just to talk in international units to include everyone: I was under the impression it was supposed to operate at 1 mbar or 1/1000th of an atmosphere. That’s into the transition between viscious and molecular flow iirc (for air at normal temps anyway). You’re probably still pumping down with something like a scroll pump but it’s not very efficient anymore.
Thinking about the number of opportunies for leaks. Every joint, every screw, every pump connection. How they all shift against each other as the sun warms and cools them, how you relieve the strain without introducing pourous materials. It’s a fucking nightmare, and even if you manage all that you need to be pumping on it every few meters 24/7 to keep pressures that low with the realistic amount of leaks/in order to be able to pump down the local area where one occurs.
Like imagine if you needed a phat motor on every block to make roads work. The infrastructure demand is just unreal
That makes no sense. It’s been repeatedly tried and failed for very obvious reasons.
Technically it’s very very hard unless you spend so much it’s uneconomic and takes too long to develop.
Secondly, its investors who were scammed. Yes they could have done better due diligence but they were still scammed.