3 ms·
When the first wave of criticism came after Musk presented his Hyperloop concept the argument I found the most compelling was that at those speeds if you change
by simias 9y ago
When the first wave of criticism came after Musk presented his Hyperloop concept the argument I found the most compelling was that at those speeds if you change direction very fast or the lateral and vertical accelerations felt by the passenger quickly becomes uncomfortable or even unbearable.
That means that if you have some kind of obstacle on the way, such as a mountain, lake or even a city you can't easily swerve around to avoid it. You either have to anticipate your turn extremely early (huge turn radius) or you basically have to tunnel through it (extremely expensive).
For the same reason if you decide to pass over mountains you might have to start elevating the track well before you meet the slope because you can't brutally change your inclination from 0 to, say, 20 degrees brutally without inflicting a few gees to the passengers. So you'd basically build a ramp to smooth it up, which would also be quite expensive.
Has this been addressed?
- pstuart 9y agoI think his plan is to tunnel through: https://www.boringcompany.com/faq/ https://www.boringcompany.com/faq/
- EGreg 9y agoAlso, what if landscapes shift due to tectonic plate movement? I'm scared to fly as it is, but hurtling through the air at mach 1 there is far less chance of an obstacle than hurtling through a cramped vacuum tube at mach 1.
- Ajedi32 9y agoIf the seal on the hyperloop is ever broken (anywhere along the loop), the tube will fill with air and the train/pod will naturally come to a stop due to air resistance.
- simias 9y agoI'm sure that it will but will it do so safely when traveling at the speed of sound? If I jump from an airliner into the ocean I'll naturally come to a stop due to water resistance but I don't think I'm going to enjoy that very much. This is a genuine question by the way, I really don't know what kind of deceleration to expect in this situation. It just seems like in this situation the train would behave a bit like a piston meeting the rushing wall of air head-on. I can't imagine that it would make for a particularly gentle stopping.
- am1988 9y agoand then what do the people inside do?
- Ajedi32 9y agoClimb out and walk to the nearest escape hatch in the hyperloop tunel. Or perhaps sit just sit there for an hour or so and wait to be rescued. It's really not that different from a subway being derailed or a carnival ride breaking down.
- EGreg 9y agoWhat if it hits something, like: An obstacle in the pipe A misaligned tunnel wall due to shifting Earth Other pods ahead of it
- Ajedi32 9y ago> An obstacle in the pipe How is an obstacle going to get into a vacuum sealed pipe? Unless there are parts literally falling off of the pods, I can't really see this happening. > A misaligned tunnel wall due to shifting Earth This would most likely break the vacuum seal and be detected immediately. > Other pods ahead of it Seems easy to avoid. We don't typically hear about trains crashing into each other, so I don't see why we'd expect that to happen with pods.
- zbtaylor1 9y agoI'm not familiar with the limitations of the system, and I know the point is speed, but couldn't they just slow down before traversing the obstacle?
- simias 9y agoI suppose, but you obviously decrease the average speed that way. It could be pretty significant too, if you want to reach bullet-train speed for your maneuvers you have to slow down to around ~300km/h from your 1000+km/h cruising speed. That's a delta-v of at least 700km/h or about 200m/s. At a deceleration of 1g it'll take about 20 seconds, and an other 20 seconds to get back to speed after that. And 1g sounds like a lot for public transportation, especially for so long. Maybe they could rotate the seats to keep the acceleration downwards from the point of view of the passengers? And obviously it'll take a lot of energy to re-accelerate the car, so you might want to store the braking energy to reuse it but I'm not sure if it's practical to store such a huge amount of energy so quickly.