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Hyperloop Alpha [pdf]

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51–60 of 202 posts

Re: Hyperloop Alpha [pdf]

#51
post #40
post #17

The focus from people on bathrooms is puzzling to me. I've been on buses, without facilities, that go for hours without stopping. This is a 35 minute ride with restricted movement, if you greatly fear being able to hold it for that long, there are other, less efficient methods of transport to accommodate you.

Yeah. Adult diapers! Problem solved.

"methods of transportation"

Re: Hyperloop Alpha [pdf]

#52
Location is a primary reason why Musk can claim Hyperloop will be cheaper than high speed rail. As the paper correctly points out, right-of-way acquisition is very expensive. Bypassing major population centers is an easy way out of using eminent domain or expensive tunneling to build the system. The HSR project is required by Proposition 1A to pass through several population centers in the state and have a couple dozen stops. Notably, Hyperloop proposes to bypass all of the SF peninsula, San Jose, and Central Valley cities like Fresno and Bakersfield. HSR was politically viable because these regions were included in the project. Furthermore, the route and station map appears to hint that Hyperloop's stations are positioned away from city centers. For example, the "San Francisco" station appears to be located in the East Bay and the "Los Angeles" station is closer to Burbank. This is quite significant from an urban planning perspective as it means that short haul transit or car trips have to be accommodated for a majority of those people who want to use the system. It also adds to the total travel time needed to get from door to door for a greater number of people than does HSR.

I'm not saying that Hyperloop is an inherently flawed project or that HSR is the perfect solution to the state's long-haul transportation needs. I just think that Musk is oversimplifying the situation.

Re: Hyperloop Alpha [pdf]

#53
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?

Re: Hyperloop Alpha [pdf]

#54
post #29

Earlier quoted context omitted.

You're thinking city buses. I'm thinking long-haul busses (like greyhound in the US). Greyhound buses likely have facilities, what I'm actually talking about are the buses used a core parts of the transportation infrastructure all over South America. Many of these also have facilities but I've been on many where the bathroom isn't functioning or just plain isn't there. You can easily travel for 30 minutes to an hour…

All these buses analogy isn't exactly the same because they still have the option to stop somewhere, which give the passengers the assurance that if they can't hold it's not the end of the world. Taking that into consideration, I think it could solve most people's bathroom concern by adding bathroom stops to the loop, in the case of semi-emergency, ideally a pod should be able to make a stop upon request within 5-10…

Financial incentive? You're traveling at 700mph through a partially evacuated, elevated tube in order to get to work. That isn't incentive enough?

Re: Hyperloop Alpha [pdf]

#55
post #17

The focus from people on bathrooms is puzzling to me. I've been on buses, without facilities, that go for hours without stopping. This is a 35 minute ride with restricted movement, if you greatly fear being able to hold it for that long, there are other, less efficient methods of transport to accommodate you.

If not using the bathroom for an hour is an issue you should see a doctor. Not only are there good treatments to alleviate this, but it may be an indication of a serious medical problem. Get it fixed then enjoy life including perhaps the Hyperloop.

Re: Hyperloop Alpha [pdf]

#56
post #42
post #30

It's too bad the tubes and trains can't be made transparent. Imagine the view!

What will probably happen is that you get a transparent car and advertisements on the inside of the tube.

That fly past a metre from your face at 1,000 km/h!

Re: Hyperloop Alpha [pdf]

#57
post #39

He doesn't properly address thermal expansion of the entire system. A long straight steel tube from SF to LA will expand a total of 300 meters over a 40C temperature change. Where does it go?

[deleted]

Re: Hyperloop Alpha [pdf]

#58
post #26

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…

Oh the irony if you try to access the bbc link http://www.bbc.com/future/story/20130812-planes-that-can-pic... from the UK :

«BBC Future (international version) We're sorry but this site is not accessible from the UK as it is part of our international service and is not funded by the licence fee. It is run commercially by BBC Worldwide, a wholly-owned subsidiary of the BBC, the profits made from it go back to BBC programme-makers to help fund great new BBC programmes. »

Re: Hyperloop Alpha [pdf]

#59
post #47
post #39

He doesn't properly address thermal expansion of the entire system. A long straight steel tube from SF to LA will expand a total of 300 meters over a 40C temperature change. Where does it go?

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 the steel tube, bending of the pylons, or both. The shock absobers will not have sufficient travel to address this, (100s of meters); axial bearings on the tube may be required.
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