kEiThZ
Superstar
Guarantee you this will never get built. The only place they can ever afford to build this are places that sparsely populated, have tons of capital and government can easily seize land. Now you know why the Emirates is onboard.
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TransPod Hyperloop
- Thread starter SaugeenJunction
- Start date
Guarantee you this will never get built. The only place they can ever afford to build this are places that sparsely populated, have tons of capital and government can easily seize land. Now you know why the Emirates is onboard.
Johnny Au
Senior Member
Qatar can build it as well for the 2022 FIFA World Cup.
kEiThZ
Superstar
The only place that can build this, is one willing to tolerate a lot of casualties at launch. And that's if they even work the tech out. So maybe China. Nowhere else is this thing going to be mature enough to build in the next decade at least. People really don't get the technological issues involved. And that's before we get into the economics which all but rules this out in our lifetimes anyway.
All the Hyperloop teams are focused on building the pods. But the pods really aren't the challenge. It's the tube infrastructure that's the real problem. This is the largest vacuum tube in the world:
https://home.cern/about/engineering/vacuum-empty-interstellar-space
Hyperloop needs several times the diameter (actually two orders of magnitude more) and for most of the proposed corridors, much longer length. I'm not sure that even near-vacuum is sufficient. As you reduce air density, Mach numbers rise for the same absolute velocity. They'd end up reducing engineering on the tunnel and then massively increasing engineering on the pods as all pods now require engineering for hypersonic flight essentially.
Can it be done? Sure. But none of the Hyperloop teams are actually working on this. At least none that I've seen. They all show nice videos of pod testing. Because nobody gets excited over the fact that you managed to maintain vacuum over several miles while inserting and removing vehicles.
AlvinofDiaspar
Moderator
To be fair they won't need anything like LHC beamline level of vacuum - and the system as proposed requires some air to work. They can probably get by with just turbomolecular pumps. Still not easy, but at least won't require crazy exotic seals and cryogenics.
AoD
kEiThZ
Superstar
Actually, we're not sure what they'll need to build a vacuum tube that large, because nobody is actually working on it!
Tulse
Senior Member
It also seems kind of crazy if the intent is that the individual lines won't have multiple seals along the route, to prevent a tube failure from flooding the entire line. That said, it may be less catastrophic to have a supersonic capsule smash into some in-rushing air than it would be to smash into a seal.
kEiThZ
Superstar
No. Equally catastrophic. And they aren't designing their pods for supersonic flight. They are designing them to operate in a vacuum. That means the normal shock that forms from air rushing in will be substantially more damaging when it hits. There are going to be Prandtl-Meyer expansion fans forming off every protrusion and those will be reflecting off the tube walls and back onto the pod.
Tulse
Senior Member
I don't know enough about the physics of these kind of situations, but I wonder how rapid a change in air density would be required for there to be catastrophic loss. In other words, would a small leak be sufficient to take out a capsule, or would it require a much larger hole to actually destroy a capsule as opposed to slow it down due to friction? Compared to, say, high speed rail, are the failure modes for Hyperloop that much worse, or easier to produce? I don't know how difficult it would be to derail a high speed train -- would throwing some rebar across the track be sufficient?
kEiThZ
Superstar
I would argue the failure modes would be substantially worse. Because of the confined space involved. If the pods are displaced in any way, they'll make contact with the tube walls.
Also, when you have the vacuum pressures involved any leak not occurring at the seal will probably lead to a rupture and more than likely explosive recompression. The air would rush in at near sonic speeds. If there's a pod heading in the opposite direction at very high velocity, the shock it experiences from the air will not just be supersonic, we'll have to discuss hypersonic aerodynamics. It's akin to hitting a wall if not properly managed.
APTA-2048
Senior Member
Brace yourselves. Transpod says their hyperloop will cost almost half that of the Province's HSR, be ready by 2025, and cost less than an airline ticket.
kEiThZ
Superstar
They can say many things. But submitting an actual proposal with those numbers in contractable terms is another matter entirely.
Moreover, if their proposals are that financially attractive, why do they need government funding? Oh that's right, private investors see right through their bullshit.
Urban Sky
Senior Member
Not sure you got the reference. Google (and watch) "Marge vs. the Monorail"...
Tuck
Active Member
Simpsons did it.Brace yourselves. Transpod says their hyperloop will cost almost half that of the Province's HSR, be ready by 2025, and cost less than an airline ticket.
Unproven tech, elevated instead of at grade over hundreds of km, needing a large tube instead of two rails, and enough power to maintain a near vaccuum.
Nope, not buying it.
The tech may work out. But cheaper than HSR? No way. Mag lev, maybe.
kEiThZ
Superstar
They are building Maglev in a tube. I can't understand how that would end up cheaper than Maglev itself.
muller877
Senior Member
I think they are trying to argue that the land acquisition cost will offset the cost of the build. Of course they also assume they can dump all this dirt somewhere for free? Let's ignore any issues with the environment by infilling Lake Ontario.