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quade

Elon Musk's "Hyperloop" announcement

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Well, very, very interesting.

http://www.teslamotors.com/sites/default/files/blog_images/hyperloop-alpha.pdf

Not precisely what some people had predicted, but also not horribly far off either.

I think it's mostly sound ideas, but I question whether the public will be willing to sit strapped into a seat like that with no flexibility in sight if they need a restroom break or have some sort of medical issue. Really cramped cabin from the looks of it.

Now, you might say he's already thought of that, but my guess is Musk has run the numbers pretty fuggin' close to optimal. I'm curious what making the vehicles tall enough for an average human to stand in and provide a center aisle would do to the design. My guess is that's maybe 2 to 4 times the current diameter.
quade -
The World's Most Boring Skydiver

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quade

I think it's mostly sound ideas, but I question whether the public will be willing to sit strapped into a seat like that with no flexibility in sight if they need a restroom break or have some sort of medical issue. Really cramped cabin from the looks of it.



It doesn't look like the most comfortable cabin, but it would only be for short amount of times. He said that its only cost effective up to about a 1000 mile distance, so the duration of each trip wouldn't be that long.
"I fly because it releases my mind from the tyranny of petty things." - Antoine de Saint-Exupery

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The inside of the tube is said to be at 100 pascals, or about 150k feet altitude (1/1000 of normal atm pressure). It would be interesting to calculate how long, and how much energy/pumping resources it would take to bring that much volume down to 1/1000 atm pressure.

They think that in the event of a severe depressurization of a capsule, they would just stop all of them and re-pressurize the whole tube. It wouldn't matter for those in that particular capsule that had suffered a really bad leak, as they would be near instantly dead. They might as well just keep the capsule going because there is no way that the tube could be re-pressurized quickly enough to save anyone. Anyway, then wheels (that were described as possibly being part of a capsule) would be needed to allow electric motors to drive the not really considered in the design wheels so as to get the capsules to a station. That would take a really long time! Every 5 miles or so there would be a capsule, trapped inside a sealed steel tube driving itself with wheels that weren't really even considered. There is no mention at all in the document of what the emergency braking system is or how it would work, just that it is there.

Really, the safety considerations section at the end of the document is a joke. What if a capsule can't be driven by the not really in the design wheels? (they ignore that possibility) Would they have to get out torches and cut the tube open to get you out 100 feet above the ground? This while in a capsule that is super cramped and has no amenities. Much worse than being trapped in a plane waiting on the tarmac for a couple hours.

They should have some way of controlling the roll of the capsule. It seems from what I read that they don't have that, except to say that when it went through the induction motor areas that it would be self aligning, but I think it would have to be pretty close as it approached. I suspect that more direct control would be needed. Taking the curves would be more comfortable if the g forces were always "down", which requires being able to roll.

edited to say the inside of the tube is at 100 pa, not the capsule.
People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am

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Alternative:

Separate right of way. Just a road. Buses and cargo vehicles that operate up to 150mph and pick up power through a catenary. Solar over the road to both shade it/protect it from weather and power it. About 2:30 from LA to SFO (faster than flying with airport time taken into account.)

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I'm wondering why it needs to be so unpressurized. Why not just have the airstream inside the tube running at a few hundred miles per hour? That lowers the resistance/friction. Or what if it's a helium atmosphere inside?

Or is that a bad idea? I can see lots of benefit of such a system.


My wife is hotter than your wife.

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One more thing: this is being talked about in these parts with a lot more excitement than the "high speed train" that is being proposed. Probably because it is inexpensive, uses an established route and is actually high speed without heavy taxpayer support.


My wife is hotter than your wife.

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>I'm wondering why it needs to be so unpressurized.

Drag. You can't get those speeds at those power levels in a more pressurized tube.

>Why not just have the airstream inside the tube running at a few hundred miles per hour?

Two reasons:

1) then you could only go that speed
2) the energy costs would be astronomical.

>Or what if it's a helium atmosphere inside?

I don't think there's that much helium on the planet.

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lawrocket

Or what if it's a helium atmosphere inside?



Helium is too valuable a commodity to be used like that.

I honestly am flabbergasted we still allow helium to be used in toy balloons. Such a fucking waste.

We have a limited supply and every bit of helium extracted from the earth eventually ends up in space. Not in any sort of climate change role or anything, just completely unrecoverable.
quade -
The World's Most Boring Skydiver

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quade


Helium is too valuable a commodity to be used like that.

I honestly am flabbergasted we still allow helium to be used in toy balloons. Such a fucking waste.

We have a limited supply and every bit of helium extracted from the earth eventually ends up in space. Not in any sort of climate change role or anything, just completely unrecoverable.



I was just thinking about the helium supply issue when I read this last night: http://www.wired.com/gadgetlab/2013/08/googlex-project-loon/all/
"There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones.

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