4 ms·

Look at the Armstrong limit (at 62,000´), a mayor problem to overcome if the tube is going to be at the equivalent pressure of 150,000´ http://en.wikipedia.org

by omegant 13y ago

Look at the Armstrong limit (at 62,000´), a mayor problem to overcome if the tube is going to be at the equivalent pressure of 150,000´ http://en.wikipedia.org/wiki/Armstrong_Limit http://en.wikipedia.org/wiki/Armstrong_Limit http://en.wikipedia.org/wiki/Time_of_useful_consciousness http://en.wikipedia.org/wiki/Time_of_useful_consciousness Also look at the TUC (time of useful consciousness) that it´s below 5 secs when flying that high. That means that you have less than 5 secs to put your oxigen mask on before you lose conciousness, or behave with out knowing what is happening. Also due to the extreme low pressure, you´ll have a horrible a horrible stomach ache due to the expansion of the gases inside you. Your blood (or at least the corporal fluids exposed directly to the low pressure) will start boiling. Not funny. Maybe one solution could be wearing some kind of pressure suit for this trips. But that is not going to be very convinient..

ricardobeat 13y ago
From the linked article: At or above the Armstrong limit, exposed bodily liquids such as saliva, tears, and the liquids wetting the alveoli within the lungs — but not vascular blood (blood within the circulatory system) — will boil away without a pressure suit As mentioned above, we have been boarding planes without pressure suits for decades, and the hyperloop has two security advantages: it has a large supply of compressed air to work with, and the tunnel can be quickly re-pressurized in the event of a severe rupture. A multitude of concurrent failures (much less likely than those in an airplane) would be necessary for a catastrophe.
- sneak 13y ago
  > As mentioned above, we have been boarding planes without pressure suits for decades The Armstrong Limit is at 62,000 feet. Jetliners fly at below 45,000 feet.
- omegant 13y ago
  A dedicated hypoxia document by the FAA: http://www.google.be/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&ved=0CFMQFjAF&url=http%3A%2F%2Fwww.faa.gov%2Fother_visit%2Faviation_industry%2Fdesignees_delegations%2Fdesignee_types%2Fame%2Fmedia%2FSection%2520II.1.2%2520Hypoxia.doc&ei=3M8JUprTFYLYPdq_gPgG&usg=AFQjCNF3H19bs-ggQODJG1FHzlyTuOVKnA&bvm=bv.50500085,d.ZWU&cad=rja http://www.google.be/url?sa=t&rct=j&q=&esrc=s&source=web&cd=... You got to think that a decompression will happen. Something traveling that fast inside a tube is probable to develope vibrations and material fatigue if something is not working properly (like the compressor or a air cushion), also there can be small parts released from the front pod impacting on the next one. It doesn´t need to be a huge crash, just a crack on the hull, it will decompress that small pod in seconds. Also what will happen when of tens of pods traveling that fast, find that there is a sudden recompression of the tube? How fast are they going to stop due to the front overpressure (the compressor is relatively low powered)?. Is not going to be a gentle stop either. I still think that it´s a great idea, and that there will be ways of solving those problems, but it´s going to be difficult and require lots of R&D.
  - DonPedro 13y ago
    Obvious engineering issues for further investigation. I would just point out that fatal failure mechanisms can be pointed out in any transportation system. The acceptance criterion is a sufficiently low fatality rate.
    - omegant 13y ago
      Are you by any chance at the hyperloop team? I see that you only commented on this topic.
dojomouse 13y ago
The great thing about the hyperloop, and other vactrain systems, is that you're at sea level... you're just not in atmosphere. The atmosphere can be restored in seconds. Sure, it'll stop the entire system and be a TOTAL pain in the arse because you'll have to restore the vacuum, but that's acceptable as long as it doesn't happen often.

by omegant 13y ago

ricardobeat 13y ago

From the linked article: At or above the Armstrong limit, exposed bodily liquids such as saliva, tears, and the liquids wetting the alveoli within the lungs — but not vascular blood (blood within the circulatory system) — will boil away without a pressure suit As mentioned above, we have been boarding planes without pressure suits for decades, and the hyperloop has two security advantages: it has a large supply of compressed air to work with, and the tunnel can be quickly re-pressurized in the event of a severe rupture. A multitude of concurrent failures (much less likely than those in an airplane) would be necessary for a catastrophe.

sneak 13y ago
> As mentioned above, we have been boarding planes without pressure suits for decades The Armstrong Limit is at 62,000 feet. Jetliners fly at below 45,000 feet.
omegant 13y ago
A dedicated hypoxia document by the FAA: http://www.google.be/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&ved=0CFMQFjAF&url=http%3A%2F%2Fwww.faa.gov%2Fother_visit%2Faviation_industry%2Fdesignees_delegations%2Fdesignee_types%2Fame%2Fmedia%2FSection%2520II.1.2%2520Hypoxia.doc&ei=3M8JUprTFYLYPdq_gPgG&usg=AFQjCNF3H19bs-ggQODJG1FHzlyTuOVKnA&bvm=bv.50500085,d.ZWU&cad=rja http://www.google.be/url?sa=t&rct=j&q=&esrc=s&source=web&cd=... You got to think that a decompression will happen. Something traveling that fast inside a tube is probable to develope vibrations and material fatigue if something is not working properly (like the compressor or a air cushion), also there can be small parts released from the front pod impacting on the next one. It doesn´t need to be a huge crash, just a crack on the hull, it will decompress that small pod in seconds. Also what will happen when of tens of pods traveling that fast, find that there is a sudden recompression of the tube? How fast are they going to stop due to the front overpressure (the compressor is relatively low powered)?. Is not going to be a gentle stop either. I still think that it´s a great idea, and that there will be ways of solving those problems, but it´s going to be difficult and require lots of R&D.
- DonPedro 13y ago
  Obvious engineering issues for further investigation. I would just point out that fatal failure mechanisms can be pointed out in any transportation system. The acceptance criterion is a sufficiently low fatality rate.
  - omegant 13y ago
    Are you by any chance at the hyperloop team? I see that you only commented on this topic.

dojomouse 13y ago

The great thing about the hyperloop, and other vactrain systems, is that you're at sea level... you're just not in atmosphere. The atmosphere can be restored in seconds. Sure, it'll stop the entire system and be a TOTAL pain in the arse because you'll have to restore the vacuum, but that's acceptable as long as it doesn't happen often.