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Now that's an appeal to authority. Regardless of whether this person is a doctor or a billionaire or a physicist, the key points (like the issues with thermal
by nonchalance 13y ago
Now that's an appeal to authority. Regardless of whether this person is a doctor or a billionaire or a physicist, the key points (like the issues with thermal expansion) are legitimate criticisms. "Dr Drang" presented arguments that are within the reach of high school physics.
Now, Musk may have an answer to the issues, but he certainly didn't present them. The fact that there is no obvious resolution suggests that either Musk didn't think of them or he intentionally omitted the answer (both are damning)
- ash 13y ago> key points (like the issues with thermal expansion) are legitimate criticisms No, thermal expansion criticism is not careful enough. See my comment: https://news.ycombinator.com/item?id=6238022 https://news.ycombinator.com/item?id=6238022
- wheremiah 13y agoYeah, this was my initial confusion with the article and many of the comments. When I read the doc by Musk, I assumed, that the tube 'floated' over the pylons. The author seems to have assumed the opposite. The problem is that they are both assumptions. When making an argument, sometimes it is good to make an assumption and then prove the assumption is false... sometimes it is just a straw man.
- rossjudson 13y agoThe tube does float (longitudinally) over the pylons, in the proposal. The tube will be supported by pillars which constrain the tube in the vertical direction but allow longitudinal slip for thermal expansion as well as dampened lateral slip to reduce the risk posed by earthquakes. In addition, the pillar to tube connection nominal position will be adjustable vertically and laterally to ensure proper alignment despite possible ground settling. These minimally constrained pillars to tube joints will also allow a smoother ride.