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Hyperloop Alpha [pdf]

spacex.com

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Re: Hyperloop Alpha [pdf]

#61

Post by conroy »

bloaf wrote: post #53
tlb wrote: post #38

I worry that the necessary straightness of the tube will be difficult to achieve. The pads float 0.5 to 1.3 mm from the inside of the tube, so deviations from straightness on that scale will cause the pads to crash. Any contact at 760 mph would probably damage the pad, plugging the air holes.

If someone shot the tube with a medium sized gun, would the impact cause an internal defect on the order of 0.5mm?

The tubes for the passenger-only version would be 20 to 23 mm in thickness. I'm not sure what damage a medium-sized gun would do to steel that thick.

Re: Hyperloop Alpha [pdf]

#62

Post by jessaustin »

mpyne wrote: post #49
jessaustin wrote: post #43

Earlier quoted context omitted.

What disadvantages do you perceive for PDF?

The same ones that we perceive for "open source development" on compiled binaries. With that said, it's not hard in this case to C&P to something more suitable for GitHub and really get things kicked off, but LaTeX would be more suitable.

Although it was effectively the case before, since 2008 PDF is an open format. It's quite misleading to compare it to a binary for which source is unavailable. Since the format specifies compression, not every part of a PDF file may be easily observed in a text editor, but there's a bunch of open software that can read (and edit, and produce) PDF.

Re: Hyperloop Alpha [pdf]

#63

Post by tlb »

nickff wrote: post #59
mpyne wrote: post #47

Earlier quoted context omitted.

If I read it right, the movement is absorbed by shock absorbers that need to be installed for earthquake protection anyways. You just need to make sure that the segment between the lateral movement/shock absorbers are sized such that the differential thermal expansion doesn't violate the deflection requirements.

The paper describes having a telescoping section on each end to accommodate thermal expansion, but the previous commenter is stating that it is likely this telescoping method will not be sufficient, as the variation in length of the structure will cause significant bending of the pylons themselves. Between the ends, there is no mechanism to allow for thermal expansion, which will either cause massive axial stress on…

Each 30M long tube expands 15mm over 40C of temperature change. You could imagine a 15mm expansion joint at each connection, which is roughly what oil/gas pipelines do, but the paper explicitly says tubes will be welded together for straightness.

Re: Hyperloop Alpha [pdf]

#65

Post by jessaustin »

Someone wrote: post #26
jessaustin wrote: post #6

Claustrophobes will not be eager to travel in this fashion.

Then use http://www.bbc.com/future/story/20130812-planes-that-can-pic... . Compared to that, this Hyperloop idea is best described as "No pilot. Less space than a 747", by teenage boys. On the other, more important hand, at firt view, this looks feasible to me (taking into account who published it) I do wonder about the "little noise" claim, though. That fan a few meters in front of you that compresses air so that yo…

The technical challenges posed by that design seem quite significant compared to those of TFA.

Re: Hyperloop Alpha [pdf]

#66

Post by cocoflunchy »

Interesting quote:

    The intent of this document has been to create a new open source form of 
    transportation that could revolutionize travel. The authors welcome feedback 
    and will incorporate it into future revisions of the Hyperloop project, 
    following other open source models such as Linux.

Re: Hyperloop Alpha [pdf]

#67

Post by mpyne »

jessaustin wrote: post #62
mpyne wrote: post #49

Earlier quoted context omitted.

The same ones that we perceive for "open source development" on compiled binaries. With that said, it's not hard in this case to C&P to something more suitable for GitHub and really get things kicked off, but LaTeX would be more suitable.

Although it was effectively the case before, since 2008 PDF is an open format. It's quite misleading to compare it to a binary for which source is unavailable. Since the format specifies compression, not every part of a PDF file may be easily observed in a text editor, but there's a bunch of open software that can read (and edit, and produce) PDF.

Producing and reading PDF isn't the issue.

Again, we have open source tools that will generate, mangle, introspect, disassemble, etc. to both ELF and PE binaries.

What PDF is not is the "preferred format for development", no matter how good the open-source tooling is.

Re: Hyperloop Alpha [pdf]

#68

Post by toomuchtodo »

alex-g wrote: post #11

It's interesting that the biggest line item in the costing is not the tube, nor the capsules, nor the vacuum pumps, nor the solar panels, nor the land, but the concrete pylons that support the tube - about two-fifths of the total. The pylons are planned to be 30m apart, making for about 25000 of them.

But that's the beauty of it! You can make those pylons anywhere, truck them in, and install them in whatever order you want. It's construction....that scales up almost effortlessly.

Re: Hyperloop Alpha [pdf]

#70

Post by sylvinus »

IMHO Musk (or anyone who follows up) should drop the "passenger" version and go with the "passenger plus vehicle" version only.

Because right now what people and the press are going to focus on is how small the cabins are, why there are no toilets, etc. On the other hand if you can imagine putting a car in there the claustrophobia argument disappears and you can think straight again...

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