5 ms·

This seems very similar to Hyperloop, up to the low pressure tube, super cheap per ride, intercontinental, and returns energy to system.

Taniwha 6y ago
Everything old is new again
ergot_vacation 6y ago
So much so that that one might suspect Hyperloop was almost entirely "borrowed" from this idea, which is probably what OP meant to suggest. To be fair, the description of Planetran does note that the boring itself is the unusually hard part. Maybe Elon saw this at some point, figured the boring part was finally solvable (which explains why he made such a big deal about it), and decided to dust it off.
- aidenn0 6y ago
  Musk's hyperloop was neither maglev, [edit it actually was an evacuated tube; just not maglev] nor in an evacuated tube. It was an air bearing in a reduced (but still fairly high) pressure tube. Apparently the air bearing didn't work out, so all the things calling themselves "hyperloop" are maglev and, once you don't need the air bearing, it makes sense to lower the pressure as much as possible.
  - qayxc 6y ago
    > It was an air bearing in a reduced (but still fairly high) pressure tube. You are a funny guy :) According to the source [0], the pressure was intended to be 100 Pa ("about 1/6 the pressure of the atmosphere of Mars"). Technically speaking, this is a fairly good medium vacuum [1]. The term "vacuum" itself refers to "a space from which most of the air or gas has been removed" [2], so you don't have to go into the intergalactic void to achieve it. I think ~99.9% qualifies as "most" :D [0] https://www.tesla.com/sites/default/files/blog_images/hyperloop-alpha.pdf https://www.tesla.com/sites/default/files/blog_images/hyperl... pg. 12 [1] https://en.wikipedia.org/wiki/Vacuum https://en.wikipedia.org/wiki/Vacuum [2] https://dictionary.cambridge.org/dictionary/english/vacuum https://dictionary.cambridge.org/dictionary/english/vacuum
    - aidenn0 6y ago
      Thanks for the correction. I misremembered it as 1/6 the pressure of Earth's atmosphere which is obviously wrong. Yes 100Pa qualifies as "evacuated" by most reasonable definitions.
- geofft 6y ago
  Musk mentions RAND's previous work in his paper, but he thinks the vacuum requirement is impractical: https://www.tesla.com/sites/default/files/blog_images/hyperloop-alpha.pdf https://www.tesla.com/sites/default/files/blog_images/hyperl... > Is there truly a new mode of transport – a fifth mode after planes, trains, cars and boats – that meets those criteria and is practical to implement? Many ideas for a system with most of those properties have been proposed and should be acknowledged, reaching as far back as Robert Goddard’s to proposals in recent decades by the Rand Corporation and ET3. [...] > Another extreme is the approach, advocated by Rand and ET3, of drawing a hard or near hard vacuum in the tube and then using an electromagnetic suspension. The problem with this approach is that it is incredibly hard to maintain a near vacuum in a room, let alone 700 miles (round trip) of large tube with dozens of station gateways and thousands of pods entering and exiting every day. All it takes is one leaky seal or a small crack somewhere in the hundreds of miles of tube and the whole system stops working. (ET3 is these folks: https://en.wikipedia.org/wiki/ET3_Global_Alliance https://en.wikipedia.org/wiki/ET3_Global_Alliance)
simonebrunozzi 6y ago
If I recall correctly, this paper from 1978 was cited by Elon Musk in the original Hyperloop paper.
dr-detroit 6y ago
That the whole point Musk is a charlatan hoovering up all the gubment subsidies that were intended to give a boost to a generation of science-based innovators.

Taniwha 6y ago

Everything old is new again

ergot_vacation 6y ago

So much so that that one might suspect Hyperloop was almost entirely "borrowed" from this idea, which is probably what OP meant to suggest. To be fair, the description of Planetran does note that the boring itself is the unusually hard part. Maybe Elon saw this at some point, figured the boring part was finally solvable (which explains why he made such a big deal about it), and decided to dust it off.

aidenn0 6y ago
Musk's hyperloop was neither maglev, [edit it actually was an evacuated tube; just not maglev] nor in an evacuated tube. It was an air bearing in a reduced (but still fairly high) pressure tube. Apparently the air bearing didn't work out, so all the things calling themselves "hyperloop" are maglev and, once you don't need the air bearing, it makes sense to lower the pressure as much as possible.
- qayxc 6y ago
  > It was an air bearing in a reduced (but still fairly high) pressure tube. You are a funny guy :) According to the source [0], the pressure was intended to be 100 Pa ("about 1/6 the pressure of the atmosphere of Mars"). Technically speaking, this is a fairly good medium vacuum [1]. The term "vacuum" itself refers to "a space from which most of the air or gas has been removed" [2], so you don't have to go into the intergalactic void to achieve it. I think ~99.9% qualifies as "most" :D [0] https://www.tesla.com/sites/default/files/blog_images/hyperloop-alpha.pdf https://www.tesla.com/sites/default/files/blog_images/hyperl... pg. 12 [1] https://en.wikipedia.org/wiki/Vacuum https://en.wikipedia.org/wiki/Vacuum [2] https://dictionary.cambridge.org/dictionary/english/vacuum https://dictionary.cambridge.org/dictionary/english/vacuum
  - aidenn0 6y ago
    Thanks for the correction. I misremembered it as 1/6 the pressure of Earth's atmosphere which is obviously wrong. Yes 100Pa qualifies as "evacuated" by most reasonable definitions.
geofft 6y ago
Musk mentions RAND's previous work in his paper, but he thinks the vacuum requirement is impractical: https://www.tesla.com/sites/default/files/blog_images/hyperloop-alpha.pdf https://www.tesla.com/sites/default/files/blog_images/hyperl... > Is there truly a new mode of transport – a fifth mode after planes, trains, cars and boats – that meets those criteria and is practical to implement? Many ideas for a system with most of those properties have been proposed and should be acknowledged, reaching as far back as Robert Goddard’s to proposals in recent decades by the Rand Corporation and ET3. [...] > Another extreme is the approach, advocated by Rand and ET3, of drawing a hard or near hard vacuum in the tube and then using an electromagnetic suspension. The problem with this approach is that it is incredibly hard to maintain a near vacuum in a room, let alone 700 miles (round trip) of large tube with dozens of station gateways and thousands of pods entering and exiting every day. All it takes is one leaky seal or a small crack somewhere in the hundreds of miles of tube and the whole system stops working. (ET3 is these folks: https://en.wikipedia.org/wiki/ET3_Global_Alliance https://en.wikipedia.org/wiki/ET3_Global_Alliance)

simonebrunozzi 6y ago

If I recall correctly, this paper from 1978 was cited by Elon Musk in the original Hyperloop paper.

dr-detroit 6y ago

That the whole point Musk is a charlatan hoovering up all the gubment subsidies that were intended to give a boost to a generation of science-based innovators.