Author Topic: The Hyperloop: BUSTED  (Read 75268 times)

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Offline SL4P

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Re: The Hyperloop: BUSTED
« Reply #100 on: July 29, 2016, 08:05:25 am »
Often projects like the Hyperloop, are used as R&D sinks to develop core technology for other future ventures.  Not to say the Hyperloop team don't believe in it, but there would be much more confidence in developing the fundamental technologies.
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Offline System Error Message

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Re: The Hyperloop: BUSTED
« Reply #101 on: July 29, 2016, 10:51:07 am »
Often projects like the Hyperloop, are used as R&D sinks to develop core technology for other future ventures.  Not to say the Hyperloop team don't believe in it, but there would be much more confidence in developing the fundamental technologies.

Actually no, if you consider the profile of the main person, the presentation and so on it is a scam. Only a bit of money goes into R&D and presentation, the rest goes into the scammer's pocket.
 

Offline mtdoc

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Re: The Hyperloop: BUSTED
« Reply #102 on: July 29, 2016, 05:23:27 pm »
How easy would it have been to do back of the envelope calculations to ascertain the potential problems of proposed NASA missions 60 years ago?

The Solar Roadways, uBeam, and Fontus apologists make the exact same comparison, and they are massively and demonstrably wrong. Don't go there, you'll only dig an embarrassing deep hole for yourself.

That's a false logic and does not address the point - which is that demonstrating potential problems with an idea is not the same as "busting" it.   As many here have pointed out the "Bust" of solar roadways was because it is easy to show that what they claim is physically impossible - not because there are difficult to overcome engineering challenges (which everyone agrees is the case for the hyperloop).

In any case I know better than to go round and round with the host of the party.  As I've said - I agree that a SF to LA hyperloop is unlikely to be built - I just take issue with TF's claim of "busting" it and with the false comparison to the solar roadways scam.
 
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Offline mtdoc

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Re: The Hyperloop: BUSTED
« Reply #103 on: July 29, 2016, 05:33:46 pm »

Actually no, if you consider the profile of the main person,

Which "main person"?

A quick look over the the Hyperloop One Team shows top execs with past successful careers and  a total of 67 (!) engineers.  Are you arguing that they all scammers?
 

Offline rrinker

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Re: The Hyperloop: BUSTED
« Reply #104 on: July 29, 2016, 09:23:25 pm »
 There's a big problem comparing costs with the California High Speed Rail thing - that "high speed rail" project is yet another government boondoggle that will make a lot of people rich with taxpayer money - the costs per mile of that project far exceeds any reasonable amount for constructing a nice solid railroad track. No privately owned railroad would ever spend that much per mile for new track. Add in that this so-called "high speed" stuff is nothing at all like Euro high speed or Japanese high speed - it's more like getting BACK to speeds that steam engines hauled trains at 100 years ago. So to say the Hyperloop is dreaming at their cost by comparing it to the California HSR project is not a fair comparison.
 

Offline StillTrying

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Re: The Hyperloop: BUSTED
« Reply #105 on: July 30, 2016, 11:31:16 pm »
and  a total of 67 (!) engineers.  Are you arguing that they all scammers?
They get paid to do interesting experiments, while assuming somebody else is doing the hard stuff.

Let's see their designs for an air-lock big enough for a train to pass through while still on it's rails!
« Last Edit: July 31, 2016, 12:00:44 am by StillTrying »
CML+  That took much longer than I thought it would.
 

Offline retrolefty

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Re: The Hyperloop: BUSTED
« Reply #106 on: July 30, 2016, 11:51:19 pm »
There's a big problem comparing costs with the California High Speed Rail thing - that "high speed rail" project is yet another government boondoggle that will make a lot of people rich with taxpayer money - the costs per mile of that project far exceeds any reasonable amount for constructing a nice solid railroad track. No privately owned railroad would ever spend that much per mile for new track. Add in that this so-called "high speed" stuff is nothing at all like Euro high speed or Japanese high speed - it's more like getting BACK to speeds that steam engines hauled trains at 100 years ago. So to say the Hyperloop is dreaming at their cost by comparing it to the California HSR project is not a fair comparison.

 And all that doesn't even take in the political issues. Do you really think they could build such a system that only served the two end cities without requiring lots of stops at other cities along the route? This idea is a true turkey and a real fiscal boondoggle.
 
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Offline boffin

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Re: The Hyperloop: BUSTED
« Reply #107 on: July 31, 2016, 05:46:48 pm »
There's a big problem comparing costs with the California High Speed Rail thing - that "high speed rail" project is yet another government boondoggle that will make a lot of people rich with taxpayer money - the costs per mile of that project far exceeds any reasonable amount for constructing a nice solid railroad track. No privately owned railroad would ever spend that much per mile for new track. Add in that this so-called "high speed" stuff is nothing at all like Euro high speed or Japanese high speed - it's more like getting BACK to speeds that steam engines hauled trains at 100 years ago. So to say the Hyperloop is dreaming at their cost by comparing it to the California HSR project is not a fair comparison.

And all that doesn't even take in the political issues. Do you really think they could build such a system that only served the two end cities without requiring lots of stops at other cities along the route? This idea is a true turkey and a real fiscal boondoggle.

Yes , it's possible to build a system that only serves a couple of cities, but the California proposal does pass through Bakersfield (300k+), Fresno (500k+) and San Jose (1m+)

How about Madrid-Zaragoza-Lleida-Barcelona; with half the trips doing Madrid Barcelona non-stop.  MAD-BCN previously being the busiest air-route in the world; and now the high speed rail has taken it out of the top 20.

So other than the argument that "you can't build it without other stops", when there are
  • Other stops; and;
  • half the trips of a similarly distance system are non-stop
Have you any other arguments as to why it wont work in the USA?   Or is it just that US engineering isn't up to European standards.

The project is only a turkey if you work in the automobile/aviation/oil industry, but sadly their lobbyists have convinced north americans otherwise.

 

Offline rrinker

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Re: The Hyperloop: BUSTED
« Reply #108 on: July 31, 2016, 06:38:59 pm »
 No, the California High Speed Rail project is a huge joke on the taxpayers, and I LIKE trains. I ride them whenever I can. In 1981 they ended service from Philadelphia to Reading where I live, now if I need to go to a client there or get to the airport, I have to sit in traffic for what is almost always a 2 hour minimum drive even off peak times. Peak rush hour, forget about it. There is pretty much only 1 way in and out of the city, only 2 lanes in each direction with a volume of traffic that would crush a road with 4 lanes in each direction. ANd since they built it along a ledge above the river there is really no room to add additional lanes. I've moved and/or changed jobs in the past to avoid having to drive this area. If there was a train instead, I wouldn't mind so much. It takes me about 3 hours or so to drive to DC, coming home is usually more like 5 hours. Last time I had to go there, I told the PM who manages all the travel arrangements to put me on the train instead. An easy half hour drive from my house to the nearest station (prior to 1981, the station was about 5 minutes from me), and about the same 3 hours on the train, except that I was relaxed and reading a book, not driving. Return trip a few days later, more of the same.
 My other hobby besides electronics is model trains, but I love the real ones too. I wish we had more of them in this country, I'd almost always chose a train over a plane. Even the commuter trains have far more room in the seats than any airplane. I also drive a fairly fancy car and would love it if the daily back and forth people would be on trains instead and keep the roads more open to drive for fun and occasional travelers.

 

Offline lem_ix

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Re: The Hyperloop: BUSTED
« Reply #109 on: July 31, 2016, 06:56:56 pm »
People don't seem to understand the most important side of engineering, COST. Sure it sounds cool and I'd like to ride one but that doesn't mean it's a good idea. Someone mentioned in a previous post that there's no alternative to the hyperloop performance, so I'll present my brilliant idea.

Lets use rockets to transport people faster then ever. At a speed of 7.9 km/s my new and futuristic transportation system tramples the hyperloop on performance. At first it might seem expensive but worry not we'll just use the Soyuz rocket which is proven technology + cheap(probs cheaper then hyperloop anyway). The vacuum for my rocket is free (space) with thorium solar panels as an optional accessory for a greener experience. Open to suggestions about a catchy name and wonder why no one thought of this before.

Jokes aside, to me at least this does seem very similar to solar roadways, something that could possibly work at an insane cost. If Elon is spending his own money on this then fine, but someone could miss out a government grant for more useful research because of this.
 

Offline stj

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Re: The Hyperloop: BUSTED
« Reply #110 on: July 31, 2016, 07:11:38 pm »
Musk is a nobody,
he puts his name on other peoples idea's and exploits government funding programs afterwards.
(reminds me of Einstein!)

read this pdf and tell me if musk was even born when it was drawn up!!!

BTW, some people think it was actually built and is in use now between military and government sites.
looking at the patents on nuclear tunnel boring systems from around the same period - it's very possible.
 

Offline rs20

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Re: The Hyperloop: BUSTED
« Reply #111 on: July 31, 2016, 07:47:28 pm »
Jokes aside, to me at least this does seem very similar to solar roadways, something that could possibly work at an insane cost.

Pedantic, but: Solar Roadways can certainly not meet its stated goals (e.g. melting snow with solar energy) at any cost.
 

Offline edavid

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Re: The Hyperloop: BUSTED
« Reply #112 on: July 31, 2016, 08:46:29 pm »
People don't seem to understand the most important side of engineering, COST. Sure it sounds cool and I'd like to ride one but that doesn't mean it's a good idea.

I guess you didn't read the Hyperloop proposal.  The whole point of it was to present a design with higher performance than CHSR, at lower cost.

You can certainly argue whether the cost estimates were reasonable, but you seem to have completely missed that Musk's proposal was all about cost.
 

Offline Mark_Of_Sanity

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Re: The Hyperloop: BUSTED
« Reply #113 on: August 03, 2016, 06:03:16 pm »
Here is an interesting response to the thermal expansion problem TF mentions.
Titled: Re: The Hyperloop Busted (Thunderf00t) - Thermal Expansion Mechanism

 

Offline TheAmmoniacal

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Re: The Hyperloop: BUSTED
« Reply #114 on: August 03, 2016, 06:12:58 pm »
Here is an interesting response to the thermal expansion problem TF mentions.
Titled: Re: The Hyperloop Busted (Thunderf00t) - Thermal Expansion Mechanism


Yep, that is the only viable solution to the thermal expansion problem in the Hyperloop. It's still extremely challenging though.
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Offline helius

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Re: The Hyperloop: BUSTED
« Reply #115 on: August 03, 2016, 07:05:34 pm »
Thermal expansion would not be a problem in a buried tube, and it would solve the vandalism problem as well.
 

Offline Maxlor

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Re: The Hyperloop: BUSTED
« Reply #116 on: August 03, 2016, 07:18:38 pm »
I'm dubious that's a viable solution. Let's do some back of the envelope calculation:

Let's say there's a 100K temperature differential we need to consider, and our pin points are 1000m apart. The elongation of steel is 12ppm, so our previously 1000m of tube are now 1001.2m long. The sideways motion to accomodate those additional 1.2m is about 21.2m at the middle at the 500m point, which is not unreasonable, it's in about the same range as a multilane highway's width. However, the hypertube cars are now also travelling through an arc with a radius of about 5.9km, which at a speed of 300m/s results in a sideways acceleration of 15.2m/s^2, and what's more, the acceleration will switch from left to right every 3 seconds. That'd be a very uncomfortable journey.

What if the pinpoints were 10km apart instead of 1km? That'd increase the radius 10-fold, which would mean 1/10th of the acceleration, i.e. about 1.52m/s^2. That's about the acceleration you experience in a subway, and I think it'd still be uncomfortable to experience that constantly, with direction switching every 30 seconds. Then again, people put up with riding the subway with its constant starting and stopping, so maybe it'd be ok. However, the sideways motion of the tube would increase by a factor of 10 too, to a whopping 212m. That's quite a bit of land use there. So it'd be both slightly uncomfortable and use an unreasonable amount of land.

So I don't think just allowing thermal expansion is the answer.
 

Offline rs20

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Re: The Hyperloop: BUSTED
« Reply #117 on: August 03, 2016, 07:49:29 pm »
Disclaimer: not trying to defend overall hyperloop practicality. Just devil's advocating.

Haven't been following this thread for a while, but how about simple sliding O-ring seals to allow for expansion? The air in the ISS is "famously" held in by a handful of O-rings: http://nerdist.com/air-pressure-on-the-iss-is-maintained-by-these-two-tiny-o-rings/ (Apologies for the sensationalist headlines.)

Obviously keeping the air out of a hyperloop using O-rings is vastly more expensive than that, but I feel like vacuum on Earth is a less precious commodity than air is 400km up where the ISS is.

 

Offline TheAmmoniacal

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Re: The Hyperloop: BUSTED
« Reply #118 on: August 03, 2016, 07:54:34 pm »
Disclaimer: not trying to defend overall hyperloop practicality. Just devil's advocating.

Haven't been following this thread for a while, but how about simple sliding O-ring seals to allow for expansion? The air in the ISS is "famously" held in by a handful of O-rings: http://nerdist.com/air-pressure-on-the-iss-is-maintained-by-these-two-tiny-o-rings/ (Apologies for the sensationalist headlines.)

Obviously keeping the air out of a hyperloop using O-rings is vastly more expensive than that, but I feel like vacuum on Earth is a less precious commodity than air is 400km up where the ISS is.

Using an O-ring to maintain the vacuum of the hyperloop would work fine - if it was static system. The problem is that the hyperloop must be flexible, allow for both thermal expansions and boarding/offloading.
« Last Edit: August 03, 2016, 07:56:12 pm by TheAmmoniacal »
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Offline rs20

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Re: The Hyperloop: BUSTED
« Reply #119 on: August 03, 2016, 07:59:25 pm »
Using an O-ring to maintain the vacuum of the hyperloop would work fine - if it was static system. The problem is that the hyperloop must be flexible, allow for both thermal expansions and boarding/offloading.

That sounds like an orthogonal concern -- I'm just talking about dealing with thermal expansion on the plain parts of the track, away from stations. Longitudinal thermal expansion is handled (I propose) by having O-rings that can slide (think telescoping action, except only 10mm per segment).
 

Offline stj

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Re: The Hyperloop: BUSTED
« Reply #120 on: August 03, 2016, 09:41:36 pm »
if it is underground the temperature will be stable and the tube can be straight A-B with no turns.
 

Offline T3sl4co1l

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Re: The Hyperloop: BUSTED
« Reply #121 on: August 03, 2016, 11:55:16 pm »
What if the pinpoints were 10km apart instead of 1km? That'd increase the radius 10-fold, which would mean 1/10th of the acceleration, i.e. about 1.52m/s^2. That's about the acceleration you experience in a subway, and I think it'd still be uncomfortable to experience that constantly, with direction switching every 30 seconds. Then again, people put up with riding the subway with its constant starting and stopping, so maybe it'd be ok. However, the sideways motion of the tube would increase by a factor of 10 too, to a whopping 212m. That's quite a bit of land use there. So it'd be both slightly uncomfortable and use an unreasonable amount of land.

So I don't think just allowing thermal expansion is the answer.

Note that, by rolling the vehicle, lateral acceleration becomes indistinguishable from (and slightly additional to) normal gravity.

The repeat rate at which the vehicle oscillates (due to a buckled or buckling-induced path) is an interesting figure, though.

Now, what about trains?  Because, so... they have 100% continuous steel tracks, and their spacings are exact.  The path doesn't shift much, relative to the Earth, even over very long distances; except on very long paths, which can buckle on very hot days.

Everyone seems to be forgetting that the Earth itself expands and contracts, and is not, itself, an infinitely rigid element!

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Offline Brutte

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Re: The Hyperloop: BUSTED
« Reply #122 on: August 04, 2016, 07:37:36 am »
I'm dubious that's a viable solution. Let's do some back of the envelope calculation:

Let's say there's a 100K temperature differential we need to consider, and our pin points are 1000m apart. The elongation of steel is 12ppm, so our previously 1000m of tube are now 1001.2m long.
Or you heat the cold 1000m pipe to that +100K limit and weld that 1001.2m to the rest of the pipe.
Or you can stretch cold 1000m pipe to 250MPa when it reaches 1001.2m and then weld it.
Or heat it to +50K and stretch it to 125MPa and then weld it.
Whatever.

In above cases it would have 1001.2m and 0Pa strain at hot days and 1001.2m and 250MPa in tension at cold days.

No curves or bumpy ride is needed.
 

Offline EEVblog

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Re: The Hyperloop: BUSTED
« Reply #123 on: August 04, 2016, 11:14:52 am »
Obviously keeping the air out of a hyperloop using O-rings is vastly more expensive than that, but I feel like vacuum on Earth is a less precious commodity than air is 400km up where the ISS is.

Yes, but the ISS doesn't have a huge object hurtling through it at the speed of sound, it's not 600km long, it's not susceptible to storms and earthquakes and rednecks banging on it, has many orders of magnitude less joints, and it has a predictable thermal and stress environment.
I'd take the ISS any day of the week.
 

Offline Mark_Of_Sanity

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Re: The Hyperloop: BUSTED
« Reply #124 on: August 04, 2016, 12:26:07 pm »
Btw for the cascading effect in the case of a rupture, surely you could design the tube to
just collapse at that point. Ofcourse it won't shut the tube with a vacuum tight seal but
it would greatly reduce the opening and reduce the inflow.
So at least it won't be destructive.

P.S.

Also why can't they drive a few stakes of steel into the earth underneath as a heat sink every 100 meters or so,
or as needed? Drive a metal rod maybe 5-6 meters into the ground with thermal insulation where needed to protect from
sun light and other sources of heat. And you would reduce some of the thermal expansion.
« Last Edit: August 04, 2016, 02:57:56 pm by Mark_Of_Sanity »
 


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