Hyperloop acceleration

Caporegime
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...but doesn't do 400mph

I think 394mph is close enough to round to 400 ;). Anyway the point being that conventional vehicles can travel at speeds not far off the hyperloops claimed 600mph at atmospheric air density, and that land speed record is 8 years old. The hyperloops only real advantage over conventional land transport is that it's more efficient, but it requires massive costs for the infrastructure and poses extra risks like loss of cabin pressure.
 
Soldato
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I think 394mph is close enough to round to 400 ;). Anyway the point being that conventional vehicles can travel at speeds not far off the hyperloops claimed 600mph at atmospheric air density, and that land speed record is 8 years old. The hyperloops only real advantage over conventional land transport is that it's more efficient, but it requires massive costs for the infrastructure and poses extra risks like loss of cabin pressure.

Using your logic of rounding up and being "not far off", I've decided that you're right. There's no need for a hyperloop when my bicycle does 600mph too.
 
Soldato
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Haha, it's not just 6mph though, is it?
You take the maximum speed of one vehicle, round that up to 400, decide that is "not far off" some sort of average or total journey speed of another vehicle.
The difference between the max speeds of those vehicles is several hundred, not 6.
 
Caporegime
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Haha, it's not just 6mph though, is it?
You take the maximum speed of one vehicle, round that up to 400, decide that is "not far off" some sort of average or total journey speed of another vehicle.
The difference between the max speeds of those vehicles is several hundred, not 6.

Ack attack reached 394.084mph so there is less than 6mph difference, most normal people round to 2 or 3 significant figures for readability, I don't understand the issue?

The hyperloop has not reached anything approaching that speed yet and technology for land vehicles is constantly improving, using non conventional propulsion like the ThrustSSC a land speed of 763mph was achieved and that was 23 years ago!

https://en.wikipedia.org/wiki/Land_speed_record

They'd be better off just building a track and putting a jet powered vehicle on it, no risk of cabin pressure loss and so so much cheaper.
 
Associate
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Ack attack reached 394.084mph so there is less than 6mph difference, most normal people round to 2 or 3 significant figures for readability, I don't understand the issue?

The hyperloop has not reached anything approaching that speed yet and technology for land vehicles is constantly improving, using non conventional propulsion like the ThrustSSC a land speed of 763mph was achieved and that was 23 years ago!

https://en.wikipedia.org/wiki/Land_speed_record

They'd be better off just building a track and putting a jet powered vehicle on it, no risk of cabin pressure loss and so so much

Yes because a motorbike going 400mph is really safe. Sure my granny will be riding one soon
 
Associate
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Ack attack reached 394.084mph so there is less than 6mph difference, most normal people round to 2 or 3 significant figures for readability, I don't understand the issue?

The hyperloop has not reached anything approaching that speed yet and technology for land vehicles is constantly improving, using non conventional propulsion like the ThrustSSC a land speed of 763mph was achieved and that was 23 years ago!

https://en.wikipedia.org/wiki/Land_speed_record

They'd be better off just building a track and putting a jet powered vehicle on it, no risk of cabin pressure loss and so so much cheaper.

Riding around on a motorbike at 400mph, sorry 394mph definitely seems like a safe way to get you and your family around. Shame they didn't have you on the original panel when deciding if this project was worthwhile or not.
 
Caporegime
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Riding around on a motorbike at 400mph, sorry 394mph definitely seems like a safe way to get you and your family around. Shame they didn't have you on the original panel when deciding if this project was worthwhile or not.

Way to miss the point.

The point is using conventional transport can get close to those speeds without needing the level of infrastructure of the hyperloop, so designing something around that, that runs on a track would be a much cheaper and probably safer way to travel. No one is suggesting riding a motorbike at 400mph...
 
Soldato
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Way to miss the point.

The point is using conventional transport can get close to those speeds without needing the level of infrastructure of the hyperloop, so designing something around that, that runs on a track would be a much cheaper and probably safer way to travel. No one is suggesting riding a motorbike at 400mph...

Something designed specifically for a land speed record is not conventional.
It needs dry ice to cool it. How many conventional petrol stations have that?
They have to wait for months for the right conditions to run it.
It needs a huge support team to get it going.
It has a range measured in single digits.
A large percentage of its runs have ended with a crash.

None of these things make it a suitable comparison to a mass transport system.
 
Soldato
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I have to say I'm disappointed by the progress of this whole project tbh, a conventional motorbike does 400mph in normal air density without any of the risks of being in a vacuum or requiring massive infrastructure etc.

Did the very early prototype motorcycles do 400mph?
 
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https://en.wikipedia.org/wiki/Ack_Attack

Conventional as in uses a combustion engine and is not using a jet engine.

That's hardly a "conventional motorbike". The engines are conventional, but the vehicle isn't.

[..] They'd be better off just building a track and putting a jet powered vehicle on it, no risk of cabin pressure loss and so so much cheaper.

A jet powered train would be interesting, but not practical or safe. Or particularly useful. At higher speeds, the main issue is the track rather than the means of propulsion. It's been possible to build a jet powered train for at least 75 years. It's not been done for several reasons:

1) Jets are very loud.
2) The exhaust could easily damage the mind-bogglingly expensive track needed for high speed railways.
3) Jets use a lot of fuel.

Jet powered trains have problems that outweigh the advantages over other ways to move a train, if any such advantages exist. There are already trains that can go >350 mph.

Way to miss the point.

The point is using conventional transport can get close to those speeds without needing the level of infrastructure of the hyperloop, so designing something around that, that runs on a track would be a much cheaper and probably safer way to travel. No one is suggesting riding a motorbike at 400mph...

The only existing form of transport that can get close to (and in one case exceed) the intended speed of HYPErloop vehicles are land speed record vehicles. Which are hardly conventional and definitely wildly unsuitable for regular mass transport.

I'm not sold on Hyperloop (and the frenetic hype over it grates on me), but there are valid reasons for running vehicles in a vacuum and it's theoretically possible to attain higher speeds than with a train on a track in normal atmosphere. Whether it's practical to do so is another matter, as is whether it's useful to do so.

EDIT: I was wrong on one point - a few jet powered trains have been built for experimental purposes. And not used because of the drawbacks. But they were built and tested on tracks, so I was wrong about that.
 
Caporegime
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That's hardly a "conventional motorbike". The engines are conventional, but the vehicle isn't.



A jet powered train would be interesting, but not practical or safe. Or particularly useful. At higher speeds, the main issue is the track rather than the means of propulsion. It's been possible to build a jet powered train for at least 75 years. It's not been done for several reasons:

1) Jets are very loud.
2) The exhaust could easily damage the mind-bogglingly expensive track needed for high speed railways.
3) Jets use a lot of fuel.

Jet powered trains have problems that outweigh the advantages over other ways to move a train, if any such advantages exist. There are already trains that can go >350 mph.



The only existing form of transport that can get close to (and in one case exceed) the intended speed of HYPErloop vehicles are land speed record vehicles. Which are hardly conventional and definitely wildly unsuitable for regular mass transport.

I'm not sold on Hyperloop (and the frenetic hype over it grates on me), but there are valid reasons for running vehicles in a vacuum and it's theoretically possible to attain higher speeds than with a train on a track in normal atmosphere. Whether it's practical to do so is another matter, as is whether it's useful to do so.

EDIT: I was wrong on one point - a few jet powered trains have been built for experimental purposes. And not used because of the drawbacks. But they were built and tested on tracks, so I was wrong about that.

Oh I am totally sold on the concept of vactrains, I had read about the concept before the hyperloop was announced, mainly maglev trains were discussed. It's just that at 600mph it seems like a bit of a vanity project when as you say we already have manned maglev trains already capable of doing >350mph without the risk of suffocating in a rapid decompression or being blown to pieces in a rapid compression event. :p I know it's just a first design but I'd have thought supersonic speeds would be the initial aim, and then hypersonic afterwards, I wasn't expecting the world but it's just a bit disappointing.
 
Man of Honour
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Oh I am totally sold on the concept of vactrains, I had read about the concept before the hyperloop was announced, mainly maglev trains were discussed. It's just that at 600mph it seems like a bit of a vanity project when as you say we already have manned maglev trains already capable of doing >350mph without the risk of suffocating in a rapid decompression or being blown to pieces in a rapid compression event. :p I know it's just a first design but I'd have thought supersonic speeds would be the initial aim, and then hypersonic afterwards, I wasn't expecting the world but it's just a bit disappointing.

I'm guessing that the target market is a replacement for air travel, which is usually ~550mph. Anything at that speed is a long haul idea. You're not going to have 600mph trains doing local transport or longer distances with frequent stops. But I'm not convinced of that use either. The air in between airports doesn't require building or maintainence. Huge vacuum tubes do. Maybe environmental grounds will be the selling point, in comparison with aeroplanes. But, like you, I'm not seeing enough of an advantage over existing trains to make a compelling case for it.

It's a bit amusing to think that hyperloop wouldn't have been a novel concept to a Victorian time traveller. Pneumatic tubes were in use from ~1850 for small objects (and still are) and back then scaling it up to train size was seriously considered and experimented with. Not the same thing, but close enough for the idea to not seem incomprehensibly strange to a Victorian time traveller.
 
Soldato
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we already have manned maglev trains already capable of doing >350mph without the risk of suffocating in a rapid decompression or being blown to pieces in a rapid compression event.

We also have planes which have exactly the same risk of rapid decompression. That hasn't stopped them from being a commercially-viable and safe form of transport.
 
Soldato
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I thought the point of hyperloop isn't just that the low pressure tube (not vacuum, but much lower then sea level air pressure) is more efficient but but that you can exceed the speed of sound. Also the tubes wouldn't be a vacuum the entire length but would be reduced in front of oncoming trains.

It should work, the physics are real and for long distance travel over land it has far more potential than air for supersonic speeds. The engineering just needs to catch up with the theory :)

Unless teleportation suddenly becomes real I think this is a tech that will come, one day, it's just a matter of time for the propulsion and materials technology to be readily available.
 
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