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The first tests of Elon Musk's revolutionary high-speed transport system could begin soon after Hyperloop One, one of 12 companies competing to make the idea a reality, completed its test track. The company has finished work on its 500 metre long testing tunnel, which is situated in the Nevada desert, near Las Vegas, and has a diameter of 3.3 meters. It is expected to run initial trials on the near-supersonic speed train in the first half of this year.
The development follows last month's news that Hyperloop Transportation Technologies, another competing company, has started building the first passenger capsule. The pods will be able to carry 28 to 40 passengers at a time and depart every 40 seconds, the company said. They could be ready as early as next year.
(Score: 2) by Scruffy Beard 2 on Saturday April 08 2017, @07:48PM (12 children)
Maybe they can prove once and for all the thundef00t's small scale test (showing a BB rocketing out of the end of a vacuum tube) does not apply in the case of a tube breach.
500m should be enough to test doors/seals without having to depressurize the whole tube every time as well.
(Score: 0) by Anonymous Coward on Saturday April 08 2017, @07:53PM
Maybe you should volunteer for it, even though you've already seen the videos explaining that hyperloop is completely infeasible?
(Score: 2) by kaszz on Saturday April 08 2017, @09:11PM (10 children)
Yummy yummy.. a tube breach feeding a colon of air weighting tons flying at supersonic speeds into the tube and pushing a small capsule to a really high speed. Oh, and no slowdown for corners..
Anyone willing to do some calculus?
Pressure = 101 325 Pa = 101 325 N/m²
Length = 2000 meter?
Force = mass * acceleration
Pod mass = 10 000 kg ?
If the acceleration exceeds 100 G, the passengers will die of that alone.
(Score: 2) by bob_super on Sunday April 09 2017, @01:52AM (8 children)
If the capsule is already supersonic, the column of air coming behind won't make it faster, but braking may be entertaining. From a standing start could be an issue, only mitigated by the low density of air.
Conversely, a column of air coming against the capsule should make it slow down pretty dang fast (and get pretty hot, potentially damaging it and/or the tube), which may be an issue for the next capsule arriving behind.
That's of course in the event of a total cross-section tube failure. A gunshot-size hole or 15 would hurt the vacuum but not cause catastrophic pressure waves to travel down,
(Score: 2) by butthurt on Sunday April 09 2017, @02:09AM (4 children)
> If the capsule is already supersonic, the column of air coming behind won't make it faster [...]
A mass of air can move at supersonic speeds, as anyone who's spent time in a supersonic wind tunnel knows.
https://en.wikipedia.org/wiki/Supersonic_wind_tunnel [wikipedia.org]
(Score: 2) by bob_super on Sunday April 09 2017, @02:13AM (3 children)
The question is whether it can just by flowing from 1 ATM into a partial vacuum.
That wiki page includes a diagram with a High-Pressure tank as input...
(Score: 3, Informative) by butthurt on Sunday April 09 2017, @02:41AM (2 children)
I see I mistook your meaning.
> The question is whether it can just by flowing from 1 ATM into a partial vacuum.
From that same article: "[t]he Mach number and flow are determined by the nozzle geometry." In this scenario the breach would take the place of a nozzle. It also mentions a "pressure ratio," saying that a ratio of 10:1 can support a Mach 4 flow.
> That wiki page includes a diagram with a High-Pressure tank as input...
In the paragraph above, it explains that that's done to conserve energy and that "another way of achieving the huge power output is with the use of a vacuum storage tank." It says that that method is limited to low Reynolds numbers (meaning laminar flow). How much of that article matches reality, I don't know. I think that if a gas is released into a hard vacuum, the speed of the molecules will follow a Boltzmann distribution: the hotter the gas, the faster they will move, with the speed of light being the only limit to their speed. However, it's been a long time since I was in science class.
(Score: 2) by kaszz on Monday April 10 2017, @11:21PM (1 child)
But what will the average speed be?
I'll guess that's what matters.
(Score: 2) by butthurt on Tuesday April 11 2017, @04:23AM
Someone made a graph for oxygen at 300 K, figure 1 on this page:
https://chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/Kinetics/Rate_Laws/Gas_Phase_Kinetics/Maxwell-Boltzmann_Distributions [libretexts.org]
The RMS speed is around 500 m/s; the most probable speed is a bit less than 400 m/s. Both are somewhat greater than the speed of sound in air, which is around 343 m/s (depending on temperature and humidity).
https://en.wikipedia.org/wiki/Speed_of_sound [wikipedia.org]
Air is mostly nitrogen, which is a somewhat lighter molecule than oxygen. Nitrogen molecules at the same temperature move more quickly, sqrt(32/28) or 1.07 times as fast (if I'm not mistaken) as oxygen molecules. So at room temperature, the motion can be faster than sound, though not spectacularly so.
(Score: 2) by kaszz on Monday April 10 2017, @11:26PM (2 children)
I'm thinking about a baseball sized hole. From say a small hole growing larger by cumulative effects within a few milliseconds to seconds. Or the whole tunnel ripped by a plane crash, Canadian oil transport explosion, car, foundation failure or plain sabotage.
Another aspect is how the concept would work if the vacuum is only partial at say 1/3 atm to make it survivable with plain oxygen tanks and tools to break free.
(Score: 2) by bob_super on Tuesday April 11 2017, @02:29AM (1 child)
Crush it in just the right way, and you may end up with the largest organ pipe in history.
The whales would be quite impressed.
(Score: 2) by kaszz on Tuesday April 11 2017, @04:19AM
I suspect the feature will offer interesting catastrophic failure scenarios. ;-)
Space elevator entangled in a Stanford torus.
Black hole containment loss.
Plastic eating bacteria.
Drowning in nanobots.
Botnet AI.
(Score: 2) by Scruffy Beard 2 on Sunday April 09 2017, @04:32AM
Thunderf00t screwed up in his calculations.
You only need to deal with the pressure wave. The mass of the air column does not matter because air is a compressible fluid.