Author Topic: Elon Musk trolling the world  (Read 6133 times)

writser

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Re: Elon Musk trolling the world
« Reply #30 on: April 11, 2017, 08:31:27 AM »
Yeah, just as impossible as a flying machine. So what? If Musk wants to try it, or wants to fly to Mars or bore tunnels: super awesome. If he fails: no big deal. I don't get the hate.
« Last Edit: April 11, 2017, 08:34:43 AM by writser »
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Pelagic

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Re: Elon Musk trolling the world
« Reply #31 on: April 11, 2017, 08:34:01 AM »

The geometry of the forces is a lot different if the pressure is external rather than internal. Because pipeline operate under tension they are much stronger than the hyperloop which operates under compression. For instance if a dent occurs in a pipeline, the forces inside the pipe will actually tend to remove the dent. Whereas with the hyperloop a dent can cause the structure to buckle and the forces will actually make the dent worse.

True, but the same argument could be made for planes.

Ultimately all forms of transport have material weaknesses that make them vulnerable to accident or attack (planes = altitude and pressure, cars = bridges and tunnels, trains = any removal of track, boats = mild issue of sinking when holed).   Yet, all work extremely well.   I have no idea whether the hyperloop will join them, but I won't be surprised if it does.

+1.   Trains have thousands of miles of unguarded tracks that could be damaged in minutes using a chain and a pickup truck.   Cruise ships can now carry as many as 5-6 thousand people, can you imagine if a terrorist sank one?   The hyperloop will be vulnerable too, just like every thing else is.

The problem with the hyper loop is that vulnerabilities extend across the entire route. If a plane flying between LA and San Francisco experiences a problem, all other planes flying that route can continue on, unaffected. With the hyperloop a problem at any point between LA and SFO is likely a death sentence to everyone transiting that route aboard the hyper loop due to the loss of vacuum and resulting shockwave of air rushing down the tube, resulting in overpressure in cars further down the line.

When detractors start to use terrorism as an argument against something it's often for lack of more well founded arguments. However, in this case whether you call it terrorism or an expansion problem due to thermal differences or metal fatigue anywhere along the several 100kms of tube, a failure is absolutely catastrophic for the entire system, something not found in other modes of transportation.

LC

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Re: Elon Musk trolling the world
« Reply #32 on: April 11, 2017, 08:57:57 AM »
Yeah, just as impossible as a flying machine. So what? If Musk wants to try it, or wants to fly to Mars or bore tunnels: super awesome. If he fails: no big deal. I don't get the hate.

There's no hate...it's like if someone told u they were only going to buy 200+ PE stocks and get become a billionaire. I mean, I personally don't think it will work but it's your money...
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Jurgis

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Re: Elon Musk trolling the world
« Reply #33 on: April 11, 2017, 09:13:55 AM »
However, in this case whether you call it terrorism or an expansion problem due to thermal differences or metal fatigue anywhere along the several 100kms of tube, a failure is absolutely catastrophic for the entire system

Is that really true? I would think that there are ways to prevent a failure in one place from compromising all the system. Clearly shutoffs or turnoffs should work pretty fine. But then I am not a mechanical engineer, so  ::)


In general though, this is a troll thread, so I might not reply to any further comments.

rkbabang

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Re: Elon Musk trolling the world
« Reply #34 on: April 11, 2017, 10:18:37 AM »
However, in this case whether you call it terrorism or an expansion problem due to thermal differences or metal fatigue anywhere along the several 100kms of tube, a failure is absolutely catastrophic for the entire system

Is that really true? I would think that there are ways to prevent a failure in one place from compromising all the system. Clearly shutoffs or turnoffs should work pretty fine. But then I am not a mechanical engineer, so  ::)


In general though, this is a troll thread, so I might not reply to any further comments.


What if the tubes were completely sealed every so many yards (or some other distance) and each gate only opened in enough time for the train to go through then closed again?

Pelagic

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Re: Elon Musk trolling the world
« Reply #35 on: April 11, 2017, 11:22:30 AM »
However, in this case whether you call it terrorism or an expansion problem due to thermal differences or metal fatigue anywhere along the several 100kms of tube, a failure is absolutely catastrophic for the entire system

Is that really true? I would think that there are ways to prevent a failure in one place from compromising all the system. Clearly shutoffs or turnoffs should work pretty fine. But then I am not a mechanical engineer, so  ::)


In general though, this is a troll thread, so I might not reply to any further comments.


What if the tubes were completely sealed every so many yards (or some other distance) and each gate only opened in enough time for the train to go through then closed again?

It would need sealed sections that the car could enter then exit, like a kilometer long airlock of sorts that had a pump mechanism to create the vacuum and then slowly bring it back to atmospheric pressure if need be. I assume the final design will likely have some kind of partitions for emergency use that would seal to prevent further damage to the system. Still, you have the issue of stopping trains in the tunnel and evacuating the passengers from within the tunnel, passengers who would still be in vacuum which would need to be repressurized.

Partitioning the tube into shorter distances does have the added benefit of allowing stops prior to the destination and maintaining a 100km section of vacuum tube would likely be easier, although still incredibly difficult, than a 600km vacuum tube. From the videos and pictures I'd estimate each each tube section is 30 meters long, meaning for the entire 600km long tube you're looking at a minimum of 20,000 welds to connect tube section, double that for the tube going in the opposite direction. Every single one of those 40,000 welds needs to be perfect to maintain vacuum along the length of the tubes, even a small issue with any one connection could compromise the entire system. 

From an engineering standpoint, it's only a bit ironic that people who are so quick to point out how susceptible oil pipelines are to leaking are faithful that the hyper loop's "pipeline", a pipeline orders of magnitude more difficult to design and maintain with little existing knowledge base to build upon, will never leak. Should the hyperloop succeed, hopefully the expertise used will trickle down into other industries because humans have been trying to build pipes that have zero chance of leaking for a long time and still haven't managed to do it.

I also question the utility of striving for close to vacuum conditions, I believe they want 1/1000th of an ATM as the pressure within the tube. Creating a tube that can hold 1/10 an ATM seems like an easier proposition and you get 90% of the benefit and avoid a lot of the risks. Musk says it will be net energy positive thanks to the solar panels on top of the length of the tube so a little more energy needed to power the cars because of the increased air resistance shouldn't be an issue.


LC

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Re: Elon Musk trolling the world
« Reply #36 on: April 11, 2017, 11:57:43 AM »
"The expected pressure inside the tube will be maintained around 0.015 psi (100 Pa, 0.75 torr)"
« Last Edit: April 11, 2017, 12:19:23 PM by LC »
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Rod

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Re: Elon Musk trolling the world
« Reply #38 on: October 12, 2017, 11:38:01 AM »
Elon's real agenda may to be to use the media to promote himself as a visionary. He may know that most of the far out ideas he is proposing, like the hyperloop, are unworkable, but it keeps his name in the news and builds his larger-than-life persona.

Why does he want to do that? Maybe because it creates demand for Tesla stock and allows it to trade at an enormous price, something that allows him to issue stock and finance the heavy losses that Tesla itself may need to sustain to gain enough scale to compete with large auto companies. Many people have pointed out that Tesla is in a tough competitive position. As the only auto company with a high priced stock that could neutralize the disadvantages he faces operationally. It gives him almost unlimited cheap financing.

rkbabang

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Re: Elon Musk trolling the world
« Reply #39 on: October 12, 2017, 12:21:52 PM »
Elon's real agenda may to be to use the media to promote himself as a visionary. He may know that most of the far out ideas he is proposing, like the hyperloop, are unworkable, but it keeps his name in the news and builds his larger-than-life persona.

Why does he want to do that? Maybe because it creates demand for Tesla stock and allows it to trade at an enormous price, something that allows him to issue stock and finance the heavy losses that Tesla itself may need to sustain to gain enough scale to compete with large auto companies. Many people have pointed out that Tesla is in a tough competitive position. As the only auto company with a high priced stock that could neutralize the disadvantages he faces operationally. It gives him almost unlimited cheap financing.

That's kind of cynical.  I don't think he "knows" that the hyperloop is unworkable.  I don't think there is anything impossible about the hyperloop or building a tunnel from NY-DC, or whatever.  It may be cost prohibitive to the extent that it is almost impossible to do currently.  But there is nothing physically impossible about it.  If there is one thing Musk has done consistently it is underestimate the time and the cost of implementing his ideas.  He's a dreamer, not a con man.  He has also accomplished quite a bit already.