3 ms·

The atmosphere isn't a liability for Maglevs, you could make hyperloop with maglev tech and it'd still work fine. The tracks don't need to be powered for most

The atmosphere isn't a liability for Maglevs, you could make hyperloop with maglev tech and it'd still work fine. The tracks don't need to be powered for most Maglev concepts; superconducting maglev doesn't use powered track. Superconducting maglev is also energetically extremely cheap from an operating perspective - it's arguably energetically expensive during construction because you need a shitload of permanent magnet material (the entire track surface is coated with it). The superconductors are the cheap part from a system perspective. Electromagnetic suspension - like with shanghai maglev - also doesn't need a powered track, the relatively small amount of power required can be supplied by onboard batteries and periodically refreshed. Inductrack can be combined with magnetic propulsion, it's just not a form of magnetic propulsion in itself. There's no obstacle to integrating a separate propulsion stage into the track (as is proposed in the inductrack based container movement system proposed for... LA?)

dnautics 12y ago
Atmospheric drag absolutely is a liability... That's the whole point of an evacuated maglev.. To make an artificial atmosphere with lower drag. Note how the mockdown chassis cross section is small relative to the tube... That's also a drag limitation; and note how hyper loop has a nearly full tube cross section.
- dojomouse 12y ago
  Sorry, I didn't word that very clearly - yes it's a liability, but it's a liability that's fairly independent of the levitation mechanism. I think it's more clear to say "That's the whole point of evacuated tube transport, to make an artificial...". Whether you use wheels or maglev or air bearings is a separate issue. Hyperloop doesn't turn the atmospheric drag into an asset - it just uses a particular method of overcoming the large liability. Because of how it overcomes it, it might be able to get away with a higher blockage ratio, but to say that with any real confidence you need to specify the vacuum level in the high-vac example you're comparing it to. And then do a bunch of compressible flow math that I've not yet seen for a high-vac ETT. This paper (http://jmt.swjtu.edu.cn/EN/abstract/abstract8587.shtml http://jmt.swjtu.edu.cn/EN/abstract/abstract8587.shtml) looks at the incompressible flow case... but that's kind of missing the point I think.

dnautics 12y ago

Atmospheric drag absolutely is a liability... That's the whole point of an evacuated maglev.. To make an artificial atmosphere with lower drag. Note how the mockdown chassis cross section is small relative to the tube... That's also a drag limitation; and note how hyper loop has a nearly full tube cross section.

dojomouse 12y ago
Sorry, I didn't word that very clearly - yes it's a liability, but it's a liability that's fairly independent of the levitation mechanism. I think it's more clear to say "That's the whole point of evacuated tube transport, to make an artificial...". Whether you use wheels or maglev or air bearings is a separate issue. Hyperloop doesn't turn the atmospheric drag into an asset - it just uses a particular method of overcoming the large liability. Because of how it overcomes it, it might be able to get away with a higher blockage ratio, but to say that with any real confidence you need to specify the vacuum level in the high-vac example you're comparing it to. And then do a bunch of compressible flow math that I've not yet seen for a high-vac ETT. This paper (http://jmt.swjtu.edu.cn/EN/abstract/abstract8587.shtml http://jmt.swjtu.edu.cn/EN/abstract/abstract8587.shtml) looks at the incompressible flow case... but that's kind of missing the point I think.