
Winning Hyperloop design revealed by MIT engineers - goodcanadian
http://www.bbc.com/news/technology-35481976
======
gene-h
Here's a bit more on the specs of MIT's design:
[http://hyperloop.mit.edu/](http://hyperloop.mit.edu/)

From the lift to drag ratio(14) and cruising speed provided(110 m/s), we can
compare it's performance to other forms of transportation(neglecting air drag)
using the Von Karmen Gabrielli diagram[0]. Using the inverse of the L/D ratio
as the specific tractive power and using the updated Von Karmen Gabrielli
diagram in [1], we find that performance is expected to be a bit better than
that of a commercial plane.

This is pretty promising. Although power required for stabilization and
overcoming air drag should be taken into account.

[0][https://en.wikipedia.org/wiki/Von_K%C3%A1rm%C3%A1n%E2%80%93G...](https://en.wikipedia.org/wiki/Von_K%C3%A1rm%C3%A1n%E2%80%93Gabrielli_diagram)
[1][http://www.ingenia.org.uk/Content/ingenia/issues/issue22/Imp...](http://www.ingenia.org.uk/Content/ingenia/issues/issue22/Imperial.pdf)

~~~
flexie
But 110 m/s - that's 396 km/h or 246 mph - about the speed of a high speed
train in Asia or Europe, give or take. And that is when the pods are empty.
Sure, without the friction of the rails and the air you save energy, and maybe
you can build the whole thing cheaper, and that's lovely and all.

But wasn't the ambition to go much faster than a train? I thought this was
about reaching speeds of airplanes...

If we are at speeds around or below 200 mph when the pods are full, SF - LA
would still take a couple of hours. A French wheeled TGV could have done that
35 years ago. A Japanese wheeled Shinkansen could have done that even before.
A Japanese or Chinese maglev version of the last 1-2 decades could easily beat
that. And that's without being stuck in a dumb tube. By the time the hyperloop
becomes a reality, if ever, there will be tens of thousands of miles of high
speed rails around the world.

The hyperloop is a sizeable amount of current hype and a future loop with pods
that barely match yesterday's high speed trains. These high speed trains,
engineering wonders that actually exist, don't receive any attention in press.
I'd say that the hyperloop has been remarkably good at sucking the air out of
the room.

~~~
creshal
> A French wheeled TGV could have done that 35 years ago. A Japanese wheeled
> Shinkansen could have done that even before. A Japanese or Chinese maglev
> version of the last 1-2 decades could easily beat that.

On very few select tracks – the Shinkansen _could_ drive 500 km/h, but is
still limited to 320 because of a lack of suitable high-speed tracks. Same
goes for the TGV, and the Germans don't even bother with trains faster than
250 km/h.

Speaking of which, Germany sold their maglev technology to Japan and China in
the first place because there was nowhere to put it _at all_. With Germany's
winding railroad network it's impossible to reach speeds high enough to
justify maglev.

400 km/h _sustained_ , over tracks longer than 400km, would already be a
massive improvement over the status quo.

Assuming, of course, the Hyperloop will be able to build a sufficient
rail/tube network.

~~~
flexie
That's the thing: This pod could potentially go 396 km/h given that they are
able to lease, buy or expropriate land in a straight enough line allowing them
to construct mostly straight tubes miles after miles and given that there are
no natural barriers like hills, mountains, rivers etc. that prevent this
either. But those same conditions are the main obstacles for traditional
trains reaching high speed. It's really hard to find land for straight rails
nowadays. Railroads tend to go from city to city, not from one point in an
empty desert to the other. So they have to bend and twist and turn or go
through tunnels. Most of the efforts on getting higher speed in Europe is
about straightening out the rails and laying down modern rails.

Maybe the hyperloop can do sharper turns at high speed, and probably next
generation of the pods or the loop allows for higher speed in general. But
that the winner of the first attempts promises 396 km/h and not the +1,000
km/h we heard about before, does deflate the whole idea.

~~~
JPKab
You are forgetting that the hyperloop design naturally lends itself towards
being placed on separate, comparatively cheap pylons, since the structural
rigidity and relatively low weight of the tube sections allows them to be far
more self-supporting than maglev tracks or even traditional rail tracks.

This essentially removes the requirement of flat land from the equation.

Also, remember that the hyperloop is really much more geared towards the
American need: large cities are separated by much greater distances than
Europe, meaning that a faster and cheaper per kilometer solution is needed
than high speed rail.

------
politician
Anyone else suspect Hyperloop is a transport technology destined for use off-
planet where it wouldn't be plausible to pave roads everywhere, where there
isn't sufficient atmosphere to support flight nor oceans to float boats?

Evacuating the tubes would be far easier on the moon or on Mars.

~~~
VeilEm
Something along the lines of a hyper loop is the kind of shower thought anyone
would have while they're stuck in traffic. "What if we just made super fast
tunnels to get us places so I don't have to sit here and deal with this shit
right now." Only in this case it was Elon Musk having the thought.

~~~
Mizza
I don't have a source on hand, but I've seen him say this was pretty much
exactly it. Has to go back and forth between LA and the bay twice a week for
SpaceX/Tesla, and had the thought for the Hyperloop while sitting in traffic.

~~~
throwaway76543
I would be astounded if he drives that commute. I used to do the same commute
two to three times a week and 35 minutes in the air beats 5 hours on the road
hands down. If you're smart about it and flexible in your schedule you can
shrink the airport time to around 20 minutes.

I could go door to door from my house in Santa Clara to my office in Burbank
in about an hour.

~~~
geofft
Is that with a private jet or something? The commercial flights between even
SFO and LAX seem to take over an hour of flight time alone. Which isn't
surprising, since it's 300 miles to cover.

~~~
throwaway76543
No, just Southwest. At the time they'd run a flight every hour between SJC ->
BUR and after a while it became really easy to gauge exactly when I could show
up and hop onto the next flight out. Cut it too close and miss a flight?
They'll just put me on the next one. No big deal. The smaller airports help
enormously in getting in and out fast -- I could walk into SJC and be on a
flight in a matter of minutes. SFO and LAX are gigantic time sinks.

Though in Musk's case I imagine he can do the private jet thing and have the
plane wait for him.

~~~
geofft
Yeah, SJC and BUR seem way better for airport time, I'm just surprised they
run a 35-minute flight. I'd have assumed SFO and LAX get faster airplanes.
Maybe half the time is lost to taxiing?

------
UnoriginalGuy
Any hints about how a broken down hyperloop train would be evacuated? Or what
happens if the tunnel suddenly pressured (e.g. aircraft/lorry hit a section
dislodging it)? Also how resistant is the design to earthquakes given the high
negative pressure (i.e. how will the flexible joints be built to both
withstand the pressure and move enough during an earthquake without derailing
the train)? How will maintenance be done on the system?

~~~
consp
The guys from the team from Delft told me there would be a shockwave which the
pods can easily resist and after about 30 seconds the tube is pressurized and
the passengers can escape. The idea is that there will be hatches every [n]
meters to allow an exit from the tube if needed.

The rest are all good questions

~~~
ackfoo
Hatches with ladders down to the ground? Great way to increase cost and
diminish reliability exponentially. Let's put a failure point every [n]
meters.

Notwithstanding, this is a distraction from the biggest problem, which is that
a decompression of one vehicle will require recompression of the entire
segment of the hyperloop, stopping all vehicles in the segment.

At the ambient near-vacuum pressure inside the hyperloop, humans cannot
survive for more than a few seconds even with supplemental pressurized oxygen
masks. There is absolutely no way to deal with the decompression of a single
vehicle other than (a) recompress the loop or (b) plan for the occupants to be
dead by the next stop.

The problem is not even decompression itself. Any failure of a sensor or
failure of communication with the vehicle for more than about 1s must be
interpreted as a decompression, with shutdown of the loop, because to do
otherwise is to plan for the death of the occupants.

Commercial travel at very low ambient pressures has significant caveats. A
plan to deal with these is going to be central to wide acceptance of the
system. This is the greatest design challenge of the hyperloop.

------
brosky117
I think it is funny to hear the objections of all the armchair scientists and
commentators. I'm sure glad we have people like you who can see straight to
the problems with the Hyperloop that no one has ever thought of. You're right.
Let's just give up on this whole idea :|

~~~
erispoe
Solving problems is not ignoring them and wish they go away. One of the
biggest problem with transportation infrastructures in the US is the cost of
the right-of-way. This is barely touched by Hyperloop (the project doesn't
account for these costs) because it focuses on the technical solution, that is
actually the easiest part.

The PG motto is more relevant than ever: make something people want. In that
case, make something that people will want in their backyard. Selling is the
hard part.

~~~
vidarh
A large part of the reason for how hyperloop is structured the way it is, is
exactly because of right of way: The proposal calls for pylons and for the
route to largely follow the highways in order to be able to take advantage of
existing right of way to minimize those issues as much as possible.

It might very well be that they should have spent more effort on that aspect,
but they didn't ignore it.

And the PG motto is great if you want to make money as fast as possible with
as little risk as possible. It's not nearly so great if your goal is to make a
major change to society.

~~~
erispoe
NIMBYs on the San Francisco Peninsula (Palo Alto, Menlo Park...) got their
pitchforks out for a High Speed Rail project that would use the existing
right-of-way and they managed to downscale the project dramatically. HSR
wouldn't disturb them in any way, it would even make things better compared to
the existing diesel CalTrain operation. Do you think they will be happier with
a series of concrete pylons? Rail viaducts exist, and people are not exactly
thrilled to have one in their backyard.

Following the highway network is great (and Germany largely does it for HSR)
but the highway system is designed with very different constraints. That might
be possible in largely desert or rural places without a lot of topography, but
highways have curves and slopes incompatible with high speed as soon as you
hit a significant topography.

The cost of right-of-way skyrockets in urban and dense environments that are
exactly the ones you want to serve with HSR/HyperLoop. Both systems are on par
in the regard. The mile-long tunnel to bring HSR in the heart of San Francisco
is expected to cost several billion dollars. The cost of the technical
equipment of that infrastructure for conventional rail is marginal compared to
the cost of digging the tunnel itself.

Sure we could solve that, with strong eminent domain powers for the state for
instance. But I'm not sure anyone wants that, nor that the Supreme Court would
let it happen.

------
lisper
Too much attention is being paid to the pods and not nearly enough to the
elephant in the room: how to handle thermal expansion in the track. See:

[http://www.leancrew.com/all-
this/2013/08/hyperloop/](http://www.leancrew.com/all-this/2013/08/hyperloop/)

~~~
tod222
There have been some comments, but I'm not sure I've seen this excellent take
on the issue.

From the linked document:

> So what’s the value of getting the vibration mode shapes of this little
> section of the Hyperloop? Simple: it makes pretty pictures you can put in
> your proposal.

and

> Nothing in this section of the proposal has “demonstrated the capability of
> the Hyperloop,” nor was it intended to. This is not simply an error. This is
> eyewash for the rubes, the surest sign you’re dealing with a snake oil
> salesman.

And now the winning design from MIT drops the air hockey suspension for
conventional magnetic levitation.

The purpose of Hyperloop isn't to build a fast, new LA-SF link, it's to kill
the California High-Speed Rail project. It's a classic case of FUD.
[https://en.wikipedia.org/wiki/Fear,_uncertainty_and_doubt](https://en.wikipedia.org/wiki/Fear,_uncertainty_and_doubt)

------
IIAOPSW
where's the part that sucks air out the front and moves it to the back? You
know, the whole damn point of the hyperloop.

Right now this is just a fancy maglev.

~~~
mikeyouse
The test track is too short to get up to full speed so the compressors
wouldn't provide any functionality at this scale.

~~~
IIAOPSW
Right but then what's the point. That you can run a maglev in a tunnel?

~~~
pinktennisballs
Evacuated tunnel. And actually it is a big deal considering the speed of
travel which presents new problems. Also all designs are focused on
scalability of system

~~~
kuschku
But then stop calling it Hyperloop, and call it the VacTrain it is.

Nothing revolutionary, has existed for many decades as concept.

------
pinktennisballs
Virginia Tech, 4th place team, will soon release its full pod design at
www.hyperloopvt.com. Several of the top 5 teams had similar designs to the MIT
pod. The teams at the top were all very close in quality.

------
yawaramin
Even if the Hyperloop is only ever used to move cargo, replacing cross-
continental trains, it would still be a very big win.

~~~
protomyth
Why? Cargo is what we do best in the US and it doesn't care how fast it gets
to the destination. Further, the car shown is far too small to replace the 125
car unit trains we send around the US. We have a larger, harder to replace
cargo infrastructure than any passenger system.

~~~
InclinedPlane
It _doesn 't care_ about speed? I think UPS, FedEx, Amazon Prime, yadda yadda,
would all disagree with you strongly. Moving cargo quickly across the world is
probably a multi-trillion dollar industry. And the car shown is just a proof
of concept prototype.

~~~
protomyth
Musk himself said this is inefficient over distance so talking about the world
is wrong. Speed in the local we are talking is not that important and the
current system is efficient. FedEx, etc. needs supersonic aircraft more than
tubes. The car size is limited by the tech.

------
revscat
How can the winning design be one that carries neither passengers nor cargo?

~~~
bcook
I thought the contest posed by Musk was a request for a proof of concept. A
test loop.

~~~
Animats
It's not a loop. Musk's test track is straight. Hyperloop Transportation
Technologies is talking about a 5-mile loop. That's more interesting, because
cornering is hard.

The MIT system is maglev against a passive track. The Transrapid system, used
in the Shanghai airport maglev, requires an active track, which is why it's so
expensive. Maglev with a passive track means a simpler track but high power
consumption on the vehicle. Power has to be supplied to the vehicle in some
way. MIT is using batteries, which is fine for a 1 mile run, but doesn't
scale.

The Incheon airport maglev just started service yesterday. It's not high speed
rail, but it's much faster than most airport trams.

~~~
mattbeckman
If only there was someone related to this project that had experience building
a business based on using batteries for transportation where other people have
previously thought wasn't possible ...

~~~
kuschku
Tesla is based on not using expensive batteries, but instead the common "same
as in every laptop" type.

They can't magically increase battery lifetime, and that's why Hyperloop will
either end up as Transrapid in vacuum (VacTrain, concept for many decades) or
not at all.

~~~
grandinj
But given that trains stop periodically, and we know how to build rapid-
recharge energy storage devices, that might not be a problem

~~~
kuschku
This is HSR done on even larger scale. It will travel nonstop for 600km+.
Recharging is an issue there.

(I don’t know if you have ever used High Speed Rail, but usually it’s a direct
city-city transport, only connecting the largest cities in the region, and
often going for a long time uninterrupted. Many countries, like Germany and
Japan, even decided to put HSR onto completely separate rails)

------
ck2
I was thinking that while this will never work for people, at least Americans
(just watch a group of us on a bus or plane) that this could work for same-day
delivery for Amazon and others and it would only have to be a fraction of the
size tube.

You'd still need a last-mile delivery but you could do warehouse to warehouse
transfers in an hour instead of days.

------
chrstphrhrt
Very naive question: if the tube is a vacuum with no drag from atmosphere, why
should a pod design be aerodynamic?

~~~
sytse
It is a partial vacuum, there is less air but the remaining air still needs to
be pushed out of the way.

------
huuu
More about the winning teams: [http://hyperloop.tamu.edu/news-release-
january-30-2016/](http://hyperloop.tamu.edu/news-release-january-30-2016/)

------
tbabb
Maglev, huh. Does that imply the track has to have embedded coils / permanent
magnets? If so, seems like that pretty much explodes the cost, no?

~~~
InclinedPlane
It's not maglev.

For fuck's sake, can people at least read the wikipedia entry on the topic
before commenting on it?

It uses an air cushion to reduce friction, it uses linear induction motors to
accelerate trains along a route, most of the time it will cost. That means the
fixed costs of the whole thing are low. The cars are pretty simple and low
cost. The accelerators are also simple and make up a tiny fraction of the
length of a track. Most of the track is just a partially evacuated tunnel,
which is cheaper to build than a maglev track.

~~~
tbabb
> It's not maglev

Oh wow, this is too much.

From the article:

> "The MIT pod has _magnet skis_ that lift it during high-speed cruising"

So, in your own words, "For fuck's sake, can people at least read the article
before commenting on it?"

The was the whole reason I brought it up. The original design called for air
bearings; the MIT team did something apparently far more expensive. This is
concerning.

~~~
Already__Taken
Air bearings require a fairly tight tolerance as to the design of the tube for
the entire run no? So I don't think it's a given magnets could be more costly
if it means you use more expensive track materials but not a high precision
construction.

Any with air bearings or magnets both being a passive track on-going costs
might favor the one geological events disrupt less.

------
listic
When will the final competition happen?

