Re:SpaceX is livestreaming a hyperloop pod competition
by zenir on Sunday January 29, 2017 @09:38PM
(#13518270)
It's a partial vacuum not a full vacuum. Stopped watching at that point..
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Re:SpaceX is livestreaming a hyperloop pod competition
by e2e8 on Sunday January 29, 2017 @10:02PM
(#13518342)
I don't think that objection, by itself, invalidates the the video author's criticisms. According to Wikipedia, the hyperloop is intended to have a pressure of 100 Pa or 0.1 % of atmospheric pressure[1]. That is not much different from a prefect vacuum for the purposes of an approximate engineering calculation.
Re:SpaceX is livestreaming a hyperloop pod competition
by ustolemyname on Sunday January 29, 2017 @10:43PM
(#13518472)
That's like saying there's no difference between 99.9℅ the speed of light and going all the way there, from an engineer perspective. Turns out, one of these requires an infinite more expenditure of energy than the other. Similarly, if you're evacuating a tube by removing gave the gas at a time, 1/1000 is attainable. 0? Not so much.
Re:SpaceX is livestreaming a hyperloop pod competition
by e2e8 on Sunday January 29, 2017 @11:06PM
(#13518547)
I don't disagree but that is not issue here. The issue is that for the purposes of discussing the mechanics of the tube like strength, seals, safety etc. the small amount of air left in the tube should not throw off simple calculations by too much.
Re:SpaceX is livestreaming a hyperloop pod competition
by Animats on Sunday January 29, 2017 @11:17PM
(#13518599)
No, the air in the tube matters, at least in Musk's original design, which has the pod running on a very thin air cushion. In practice, most designs are maglev, for which a hard vacuum is best.
Re:SpaceX is livestreaming a hyperloop pod competition
by e2e8 on Sunday January 29, 2017 @11:37PM
(#13518716)
But that amount of air may not matter too much for the points discussed in the video which have to do with strength, seals, etc.
Re:SpaceX is livestreaming a hyperloop pod competition
by TeMPOraL on Monday January 30, 2017 @03:17AM
(#13519425)
That, and AFAIR original design had a system to pull the air from the front to the back, thus lowering the drag while reducing the need for lower air pressure.
Re:SpaceX is livestreaming a hyperloop pod competition
by stephen_g on Monday January 30, 2017 @12:59AM
(#13519022)
There's no such thing as a 'full vacuum' in the real world. If you think that invalidates the arguments in the video then that likely means that you need to do more research on vacuum systems...