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Hyperloop

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Re: Hyperloop

#951

Post by DonPedro »

macinjosh wrote: post #127

For all of you whose panties get wet at the sound of Elon Musk's name Hyperloop is essentially just Aérotrain in a tube: https://en.wikipedia.org/wiki/A%C3%A9rotrain This guy isn't really a genius, he's just rich.

Just the simple fact that the Aerotrain was on a track and not in a tube makes all the difference in the world. And I don't get this "look someone proposed something similar before" thing (everything from vacuum tubes to maglev to this thing). These previous inventors failed to get their ideas realised. Now a visionary has his own tweak on things and should have a good shot. Rejoice!

Re: Hyperloop

#952

Post by DonPedro »

tocomment wrote: post #854

A thought I just had, could a hyperloop like technology be used to launch ships into orbit? Why or why not?

Not by itself, but maybe in combination with another technology: http://www.popsci.com/technology/article/2010-11/nasa-engine...

Whatever you were launching would have to move through normal air, not the minimal pressure you have in the Hyperloop tube. It is hard to pass an airlock at supersonic velocities...

Re: Hyperloop

#954

Post by DonPedro »

bitteralmond wrote: post #463

Aside from the whole "will they actually build it" debate, I'm worried that if they do, the capsule ceiling won't be high enough for someone fairly tall (let's say 6'5'' or taller) to sit in comfortably. I'd assume the height of the capsule will have some effect on the drag involved, as well as the necessary size of the tube, so it makes sense to make it as short as possible. Musk himself stands just below 6', so he…

Re. headroom in Model S: http://www.teslamotorsclub.com/showthread.php/10879-Any-tall...

Re: Hyperloop

#955

Post by DonPedro »

jcromartie wrote: post #236

Does anybody else wonder how easily the rotor will slot into the stator at 700 MPH? It looks like pretty small tolerances. Maybe guide rails leading up to it?

This, I thought.

"Maybe guide rails leading up to it"

Re: Hyperloop

#956

Post by Balgair »

Balgair wrote: post #413
HCIdivision17 wrote: post #326

Earlier quoted context omitted.

To me, a 1/1000 atmosphere vacuum system IS a really leaky machine :) Anecdotally, the machine I used to work on would gleefully chew on that for hours idling while we scrambled to find the hiss on the system. It made an awesome sound when it ground into the atmospheric pressure on initial pumpdown, but at about 1/100 atmo it got bored (mere minutes), and without additional high speed stages the mechanical pumps woul…

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…

Edit: My original post says 10E-6 atm. I misremembered, it was 10E-9 tor (about 1E-11 atm). 10E-4 atm is about 0.75 tor.

Re: Hyperloop

#957

Post by Balgair »

HCIdivision17 wrote: post #606
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…

To geek out for just a moment on the topic: we had two fix-a-flat substances that required two engineers to agree to use (mostly as a joke interlock - someone had to stop management from slathering it on everything). One was basically putty that you could smoosh over a leaky o-ring (clamp and all); with some work you could seal anything for a few days, but it made an awful mess and it was darn near guaranteed to dest…

Guaranteed. This is going to end up as a union job due to the height requirements and the vacuum. It will be an honestly dangerous job. That means quotas and cutting corners, because there will be humans and it will be 105 out and I just wanna watch the Giants game, man.

Eventually, it'll all add up.

Re: Hyperloop

#958

Post by Balgair »

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

That is sooo cool!

Re: Hyperloop

#959

Post by Balgair »

HCIdivision17 wrote: post #592
shabble wrote: post #559

Earlier quoted context omitted.

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 t…

So, young man deciding on the Marine Corp or the French Foreign Legion: Just wait 10 years. Those precision welding jobs 50 feet up next to 1 tor vacuum are going to pay out the bank. Union too, and probably never going away if this thing comes to fruition.

On the other side, Mr Musk gains a hell lot of know-how about plugging vacuum leaks quick, reliably and possibly automatically. Where do you think that might come in handy? Hmmm, on trip to Mars maybe?

Re: Hyperloop

#960

Post by Balgair »

Daniel_Newby wrote: post #717
HCIdivision17 wrote: post #592

Earlier quoted context omitted.

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 t…

I would actually expect leaks to be easy to detect. Just run a high-frequency high-voltage plasma discharge detector on a skeleton vehicle. Wherever the discharge quenches you have a leak. Barcodes laser etched during construction could help you localize the leak to within a few centimeters. Pinholes might be repairable by pressing a sapphire drift against the leak and melting the metal underneath by shining a laser…

True, but this either has to be done by paid union labor 50 feet off the ground near 1 tor vacuum or by a heck of a robot. The union guys will be certified up the wazoo and paid to match that and persnickety about it. The robot will be and engineering marvel and a hell of a good idea.

I mention in another reply that Mr. Musk also has plans that involve vacuum differences and not a lot of wiggle room. On a trip to Mars a robot hull fixing machine would sure be nice to have.

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