August 13, 2013

"Why Elon Musk's 'hyperloop' transport won't work."

"[T]raveling faster than a jet aircraft in a tube would be really, really difficult."
Sam Jaffe, writing on the Navigant Research blog, says... "The biggest concern with this plan has to do with temperature. The pod will be compressing air and expelling it downwards and backwards. All that air compression creates an enormous amount of heat, which can damage the pod and its machinery"....

Musk's idea isn't new. Ever since pneumatic tubes using negative air pressure to shoot capsules through tubes showed up decades ago -- department stores used them for transactions and newspapers used them to carry stories from the newsroom to operators that would produce metal type for the printing presses -- people have dreamed of traveling through cylinders at high speed.
I remember those pneumatic tubes in department stores...





Imagine traveling like that.

I believe the truly modern technological solution is not to travel at all. Overcome the need to have the body go anywhere. That's the most efficient answer to our transportation problems. Musk's tube would supposedly get people back and forth between San Francisco and Los Angeles. Why? Pick a city. Stop this senseless flitting from one city to another.

36 comments:

AaronS said...

Did we really need this article to tell us it wasn't workable? I mean seriously, this wasn't even believable enough to get through a sci-fi book edit. Just take a few minutes to imagine all the problems related to travelling through long distance tubes at incredibly high rates of speed.

Staying in your own city is one way to handle transportation issues. Another is not to expect a long trip to be a short one.

Sam L. said...

Pick a place and stay there? Well, that's just SILLY!

bpm4532 said...

Two comments:

1. Pneuematic tubes work on negative air pressure, not the ultra low pressure envisioned by Musk and even with what little air is sucked in by a fan to counter gravity with the rest pushed out the back. Conclusion, heat would not be that much of a problem, particularly at subsonic speeds.

2. Why travel? Why even leave your home? Just get everything in audio and video from the screens around you. Better yet, when the technology is available, just plug it directly into your head. In the year 2525...

Conserve Liberty said...

When I started as a stockbroker in 1982 the order room - where orders were transmitted to the exchange over a private wire system - was on the other side of the building.

I wrote a paper ticker (3-part carbonless), rolled it an slid it into a clear plastic 2" diameter cyclinder, opened a 4"x4" door in the wall and dropped it down the tune. The door was called a tube station and there were a couple dozen of them throughout the office.

The wire operator opened the cyclinder at her end of the tube station, removed and time-stamped the ticket, did her thing and returned to me a copy with the time stamp.

We really did the business that way just 31 years ago.

bpm4532 said...

From my graduate engineering viewpoint, while the paper is on the level of a junior-year college paper, there's little that couldn't be made to work. Likely a smaller pilot project would be necessary and I would hope that Disney might see enough interest into it to invest $20-30M and turn it into an amusement ride or for transport to/from the airport.

On the social side, I'm not sure how being put into a windowless tube for 30 minutes (or more for longer journeys) would sit well with most people. I don't think they could even consider putting windows in the pods or the tubes. It's one-thing to look down from 30,000 feet going 500 miles per hour, the scenery doesn't change that fast. However going 500 miles per hour at tree level might be truly nauseating.

Logistics of bathrooms and beverage service will be interesting.

JRoberts said...

It depends on how you define "works".

If your goal is to revolutionize travel, it probably won't work for the foreseeable future.

However, if your goal is to present a visionary concept to get government grants, this thing could be a huge success. Hasn't Musk already made millions of dollars off venture capitalists and government grants from his previous failed ventures?

SteveBrooklineMA said...

AaronS is right. It's strange to me that Musk, who seems like a smart guy, would even suggest it.

Ann is 100% right about not traveling so much. In fact, I would suggest that the government use tax incentives to discourage business travel more. Of course some travel for business will always be necessary, but much of it could be done via teleconferencing.

Brian said...

Has anyone ever gotten so rich and famous for talking about shit that will never get built as Elon Musk?

Unknown said...

I always thought there was a startup in this. Work with corporations in City A and B to trade employees so that the City A residents work in the City A company and the City B residents work in the City B company. No more flitting back and forth. Sure there would be some logistical issues and some convincing to do, but it is the green thing to do, dontcha think?

Sigivald said...

Aaron: It's perfectly believable. RAND had a white paper on it decades ago, declaring it expensive but possible.

It might not make economic sense, but it's perfectly possible.

Remember, contra Navigant, that it's a low-pressure tube; a partial vacuum. It's not just a tube containing air as if it were outdoors.

And contra USA today's headlines, Navigant's non-engineer "guy who worked with pneumatic tubes operating on entirely different principles" claims it faces "hurdles", not "it won't work".

He's right, but none of the ones he mentions are remotely insoluble.

(I'm generally a skeptic of such things, but the only skepticism I have of this project is whether it makes economic sense, not whether it would work.)

(And lastly, one nitpick: "high rate of speed" is nonsense. Speed is already a rate of travel.

Adding "high rate of" in front of "speed" is just a long and confusing way to say "high speed" or "really fast".)

Levi Starks said...

The grass is always greener at the other end of the tube.

I think that many people over the years including myself have envisioned such an Idea, But after reading 1984, it kind of sounds like a memory hole, and Im not so sure I would want to be put in one.

Peter said...

Wasn't this a new idea in, umm, 1867?

http://en.wikipedia.org/wiki/Beach_Pneumatic_Transit

traditionalguy said...

Actually article praises the idea and adds that there are a few problems to be solved on removal of air compression heat and building sturdy towers that will withstand surface winds. All of the rest of it works.

The system apparently will be best for 300 mile or less trips because it beats airlines there. That also means it handles the inter-city lines like Chicago to Milwaukee much better than Obama's Bullet Trains.

JackOfVA said...

The design summary recognizes the temperature increase from air compression.

The solution is a tank of water in the capsule in an intercooler arrangement.

The actual propulsion is via linear electric motors spaced about 70 miles apart. This works because the low friction of air bearings and the supplemental propulsion from exhausting some of the compressed air from the rear of the capsule.

CarolMR said...

Sounds like a really fast MRI machine - ugh!

sojerofgod said...

Everything new is old again. R.A. Heinlein wrote a short story in 1940 called "The roads must roll" about an intercity transport system, in his case, high speed moving sidewalks that had shopping and café services for commuters. Not sure how well the analogy works, but interesting nonetheless.
a link: http://en.wikipedia.org/wiki/The_Roads_Must_Roll

rcommal said...

.

rcommal said...

"Things People Said: Bad Predictions

It'll Never Work!


bandmeeting said...

the truly modern technological solution is not to travel at all. Overcome the need to have the body go anywhere.

Go ahead and enjoy that life. I'll be traveling and enjoying unfamiliar places. I have no desire whatsoever to overcome that need.

Dog sledding in Greenland in March for me. I guess I could sit around and read about it but sometimes experiencing things is better.

Alex said...

Maybe we should work on the Star Trek transporter instead of this boondoggle.

Bruce Hayden said...

Near vacuum is somewhat of a necessity here, since otherwise the air in front of the vehicle would compress, and compress, and compress, etc. Not only would there be heat problems, but the energy required would increase exponentially. One solution to this might be some sort of pre-exhaust system that reduces this pressure as it builds, so maybe some sort of valve system could be utilized to allow the air in front of a vehicle to be exhausted, which might also help in keeping the air pressure in the tube low Except maybe that the pressure behind the vehicle is likely dropping just as quickly, and this too exerts a force on the vehicle that needs to be overcome.

The classic problem envisioned with most such systems over an extended distance is first maintaining the lower pressure over such a distance, which is, again, exponentially harder, and the reality that the longer the distance, the greater the amount of air that needs to be compressed in front of the vehicle, and the amount of negative pressure behind that needs to also be overcome. One solution might be interim seals that the moving vehicle might successively breach as it travels along the tube. For a local type transportation, this might be accomplished with a sort of air lock system as vehicles enter and leave stations. But, this wouldn't work for longer distances.

Should be interesting. Right now, I just don't see the economics working. Too much energy expended to handle air pressure and heat dissipation, esp. compared to travel outside where displaced air is just shifted into or out of the atmosphere, and is thus significantly much less of a factor or concern.

Alex said...

I wan to take a hyperloop to New Zealand.

Levi Starks said...

This Blog has certainly eliminated any need I might have ever had to go to Madison WI...

Crunchy Frog said...

Or we can all go to Recall, Inc. to have our travel memories downloaded into our heads...

southcentralpa said...

Forget travel, as an electrician I can't get over the tube installations. If you think that bending and arranging conduit like that is easy, you are SADLY mistaken ...

jimbino said...

If you were to install a straight tube from any city to any other city on earth and evacuate the tube, your travel time in the pod, by gravity only without any expenditure of energy, would be some 57 minutes (IIRC). Regardless of cities, whether LA to SF or Washington to Beijing.

The Godfather said...

I'm in favor of trying any technology that people are prepared to invest their own money in -- not the Government's. So, no Obamatrains.

I don't think Prof. Althouse could possibly be serious about not traveling. She's shared travels with us (including travel for her wedding, of which she recently reminded us). This past June my wife and I took our grandchildren (and their parents) to England for a week. Yes, you can look at pictures of the Roman baths in Bath, the ruins of Glastonbury Abbey, etc., but it isn't the same.

And my brother lives in California and I in NC; do you really think Skype is the same as being there?

It IS true that a lot of business travel can be eliminated, and in fact is being eliminated by the for-profit sector. The big travel boondoggles seem to be in the public sector: E.g., the IRS and the periodic global warming conferences. Say, why don't we put all those folks in the supersonic pneumatic tube for the test run? That's a no-lose proposition.

The Godfather said...

I'm in favor of trying any technology that people are prepared to invest their own money in -- not the Government's. So, no Obamatrains.

I don't think Prof. Althouse could possibly be serious about not traveling. She's shared travels with us (including travel for her wedding, of which she recently reminded us). This past June my wife and I took our grandchildren (and their parents) to England for a week. Yes, you can look at pictures of the Roman baths in Bath, the ruins of Glastonbury Abbey, etc., but it isn't the same.

And my brother lives in California and I in NC; do you really think Skype is the same as being there?

It IS true that a lot of business travel can be eliminated, and in fact is being eliminated by the for-profit sector. The big travel boondoggles seem to be in the public sector: E.g., the IRS and the periodic global warming conferences. Say, why don't we put all those folks in the supersonic pneumatic tube for the test run? That's a no-lose proposition.

MarkD said...

There is too much I've never seen. You can stay home. I've still got places to go and things to see.

sinz52 said...

This idea was tried, way back in 1869, in Lower Manhattan in New York City.

This fellow named Alfred Beach built a 300 foot long pneumatic subway tunnel, and blew a subway car back and forth through it with compressed air.

http://en.wikipedia.org/wiki/Beach_Pneumatic_Transit

He never got funding to scale up his idea, and even this train line eventually failed.

chuckR said...

One thing I didn't see in the white paper was a discussion of how you handle heading changes in elevation and direction - turns in the tube. Momentum is a bitch - 3 tons moving 1000 ft/sec is going to generate some significant thrust with heading change. Delta mV and all that. Large water supply lines handle this with honking big concrete reaction blocks at turns and valves. Maybe inertial resistance could be, or is, designed into the pylon system. Plus you need to keep any heading change gradual enough not to upset the passengers.

Even if you get all the details right and have a successful demo project, it doesn't matter. State and Federal red tape would probably doom this in my lifetime. How many shovel ready projects actually happened under our fearless leader the past few years?

mikee said...

A late 1970s anthology of short story Science Fiction included a story describing Althouse's ideal.

Instant video/audio/text/data communication between people and total availability of all information resources via something quite like a super duper internet led to the rich becoming isolationists in the extreme, to the point that a woman forced to travel finds herself flying over the Himalayas and sees nothing worth the effort of observing.

With great introversion comes great disassociation.

Ann Althouse said...

@mikee I think it's a limitation in the capacity to observe that makes people think they need to rove. If you really paid attention to your surroundings, you could be endlessly fascinated by your home town. It's similar to the value of a marriage compared to multiple sex partners.

Ann Althouse said...

Funny that you mention the Himalayas, because my favorite line in my favorite movie says if you could really see the cigar store next door, you wouldn't have to go to Mt. Everest.

Ann Althouse said...

The Everest quote is here:

http://althouse.blogspot.com/2013/07/what-do-you-think-difference-is-between.html

Ann Althouse said...

" Tell me: why do we require a trip to Mount Everest in order to be able to perceive one moment of reality? I mean...I mean: is Mount Everest more "real" than New York? I mean, isn't New York "real"? I mean, you see, I think if you could become fully aware of what existed in the cigar store next door to this restaurant, I think it would just blow your brains out! I mean... I mean, isn't there just as much "reality" to be perceived in the cigar store as there is on Mount Everest? I mean, what do you think? You see, I think that not only is there nothing more real about Mount Everest, I think there's nothing that different, in a certain way. I mean, because reality is uniform, in a way. So that if you're--if your perceptions--I mean, if your own mechanism is operating correctly, it would become irrelevant to go to Mount Everest, and sort of absurd! Because, I mean, it's just--I mean, of course, on some level, I mean, obviously it's very different from a cigar store on Seventh Avenue, but I mean..."