Hyper-loop Doubts

Let's do the math.

It's 350 miles, as the crow flies.

Now, let's round the price down to just 1 billion $ a mile and assume the the track is straight.

We haven't bought the land needed, the "floating" stock, hired employees, put any support structures in place etc.

How will a round trip ticket cost?

Looks pricey to me.

Just get AMTRAK to run it. The fares are guaranteed to be below cost that way.

I say we should bring back the electric trolley but use super capacitors with fixed stops that are charging points.

What happens to the people underground when an earthquake strikes?

It isn't underground, is it?

Doesn't matter, they'll die anyway.

I read while testing they have a speed limitthe test track will be limited to 160mph with passengers on board but empty carriages will be tested at speeds up to 780mph

not too much, it's an on the ground system

before today I had always read the pod/car would ride on air bearings. today I'm reading its more like MagLev......Interesting, maybe the numbers just didn't pan out once it went from concept to slide rule calcs

"slide rule calcs"?

Shirley you jest.

figure of speech. I always wondered about the leasing edge of an air bearing @ 700MPH

a handful of rice or a bag of marbles could be upsetting

On the face of it, travelling in a vacuum tube will reduce gas based drag to zero. You will also be unable to use air based levitation, of the rent based, leasing edge - as Mr Typo says, if any rice or marbles(used for some sort of bearings???) are found in there.

They speak of Halbach arrays allowing for levitation based zero friction bearings for these pods.

I can see no technical reason why this will not work. I initially feared that some sort of oscillation would occur that would lead the force separated planes to impact, but it is my understanding that control circuits measure the separation and superimpose transient fields to prevent any such oscillations from starting and self amplifying.

So we are left with the cost of the pod, the cost of the vacuum chamber and halbach track, pod array and the control circuits. In addition, drive will also be needed, which would need to be on the order of .5 to 1.5 G to reach cruising speed, as the passengers can tolerate. Maintains speed will need a lesser amount of drive to offset drag, and a deceleration force of a similar magnitude at the destination.

I would imagine that friction brakes would be installed and act as an emergency method.

The sealed pod needs air heat/cool etc. They might not have a toilet, as at 700 mph Las Vegas is only a little more than a half hour trip. They might add communications, cell connections, Wi-Fi etc, for a small fee.

So Elon will build this, assess the costs and feasibility of maintaining an evacuated tube between Las Vegas and LA, of arranging a pumped down air lock at each end.

In theory, a leak free tube is easy to make and maintain. Stray leak detectors = needed. Sabotage?

Earth Quake? Detectors, as used on the Japanese bullet trains, would apply the brakes as soon as a tremor is detected. These have worked well in quake prone Japan.

It will be interesting to see how it works out as a project not made by government. We know a government project will not be economic for that reason alone, since government lack of decision, crooked ness, unions etc will wreck it aborning.

about a week ago I watched a vid of the CEO and stated the interior pressure was expected to be 0-1Psi so not a true vacuum but a reduced pressure tube the fan in the nose was for scavenging

yes, drag will be less than ground level. It might be quite doable to reach and maintain a vacuum, with proper surface sealants, joints etc, and just have a scavenger for any small leakages.

as I stated, the intent is NOT to achieve and hold a vacuum Huge difference

It all depends on teh steady state.

The driving pressure difference between innards at <1 psi or a near vacuum are minimal.

I would have to compute the drag, but it varies as the square of the velocity. A area of 2 square feet at 100 miles per hour has about 150 pounds of drag at STP.

200 MPH = 600 pounds, 300 MPH = 1350 pounds, 400 MPH = 2400 pounds

600 MPH = 5400 pounds ate so forth.

There is a large premium that will drive a full vacuum, so that is what this test track with determine. Can a full vacuum be reached> or will <1 PSI be tolerated as the most they can hope for.

It seems to me that a properly built tube, as said, sealed, would be doable.

similar article, more data

I think the information you have for the price is in error. I looked a wired.co.uk article that mentioned the 6 billion$ figure ( http://www.wired.co.uk/news/archive/2015-10/23/elon-musk-hyperloop-test-track.) Under the comments, the deputy chairman of Hyperloop Transportation Technologies said the price would be more like 150 million$. (cough...cough, yeah, right, like that price will stand.) Aurizon, in post#16, linked to another article with 150 million $ price tag.

Still, as for myself, I cannot see why anyone would be in such a hurry to go to either L.A. or San Francisco.

I live in the UK so my comments are biased by my own government's support for a very light coloured pachyderm railway project called HS2, being pushed ahead without any passenger demand. Your comment about who wants to travel this route at this speed nails it. I have travelled both LA-SF and NY-Wdc. My few fellow passengers on LA-SF and back typified Californian laid back coolness and showed no inclination to rush from A to B. My packed like sardines fellow travellers on trips NY-Wdc and back were people desperate to get to the other end. The LA-SF chosen route for this revolutionary bit of kit is 400miles, in an earthquake zone, with limited passenger demand. A more obvious NY-Wdc choice would be 260 miles, with no earthquake risk, and massive passenger demand. It takes longer to take a taxi from Manhattan to the airport than it would to cover the whole journey city center to city center.

"...my own government's support for a very light coloured pachyderm railway project called HS2..."

Well of course! it will provide them a source of raw material to build themselves more ivory towers.

Also being in the UK, HS2 is absolutely no benefit to me. I will probably not live long enough to use even it - if I could afford it - not that it goes anywhere I want to visit - in the meantime I will be hit by the construction work by the track being a few hundred yards from my house.

On balance I am not against it. A massive national infrastructure product - whether needed or not - could generated high employment to everybody's benefit - and when finished we will have something to show for our money.

Like Egyptians didn't need pyramids - but they were all employed building them - and - and where would they be today without this major contribution to their tourist industry.

As for the engineering merits of the OP - are the costs cited related to the finished product, or just the test track?

For that kind of money we could buy a fleet of these CH-47F transport helicopters at around $35 million each, and fly people much further, and to different destination points, not to mention you get machine guns...

If I'm travelling 700 mph, I don't want anything solid anywhere close. I feel much safer with cubic miles of air around me in an airplane.

Do we really want to have to find out what wreck looks like when a (vehicle of any kind going > 700 mph) is eventually impacted by an earthquake?...

According to this video, it could even be free!

http://www.sciencedaily.com/videos/dcf374208ea62c1e76b5d815dcc5f864.htm

By the way, did anyone else notice that the longitudinal cross-section is roughly shaped like that of a wide flat airplane wing?...

Thus, the faster it is powered, the greater the uplifting (force) would be, even in near-vacuum conditions, and the more violently it would fly off the track, unless otherwise restrained...

That's perfect for the illegal 'tourists' moving between sanctuary cities.