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 cle

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.