5 ms·

The article is full of cant in more ways than one, and more about social norms when entering a new field than the proposal itself. This is obvious from the kind

by zeteo 13y ago

The article is full of cant in more ways than one, and more about social norms when entering a new field than the proposal itself. This is obvious from the kind of nitpicking that goes on (no references! 4.37 m/s^2 is the maximum motion sickness possible because an accredited expert proposed it; I've never seen 4.9 m/s^2, but it's surely a barf comet!). Despite the author's high opinion of his own knowledge, the criticism amounts almost entirely to basic arithmetic and comparisons to existing systems that are built on rather different principles. The really interesting, constructive questions: does this low-pressure air cushion thing really work? what are some factors that we need to explore to determine its true efficiency? etc. are of no interest to this kind of expert, who is more interested in tribally defending his own turf (see the unnecessary name calling) than in figuring out new ground. In all fairness, I would give much more slack to an engineer talking about his field. But, as the author himself points out, almost all civil engineering technology is from the 19th and early 20th century. He seems to think that, in between, his colleagues have been perfecting the fine forms of the art and polishing its many facets. Except feats that were once fairly common, such as building the Hoover Dam under budget and two years ahead of schedule [1], are in the realm of the mythical these days. [1] http://en.wikipedia.org/wiki/Hoover_dam http://en.wikipedia.org/wiki/Hoover_dam

Retric 13y ago
I would add he completely ignores the fact he runs a SpaceX which has significantly under cut a long established industry. If you look at his numbers there Basicly estimates for actual costs before padding where large contractors pad construction costs as much as possible because that's how they maximize proffits.
- mjn 13y ago
  SpaceX is based on a fairly different principle, of taking proven designs from the past, updating them, and building them for less. For example SpaceX's Grasshopper VTVL is following in the footsteps of the 1990s McDonnell Douglas DC-X, not some kind of completely untested idea. He isn't taking a previously speculative technology idea, like a space elevator or something, and trying to build it. An analog here would be if Musk had a proposal to take an existing, working mode of transit (at least working in prototype) and build it for less. But the current proposal is more like hard sci-fi: goes into enough depth to be back-of-the-envelope plausible, but no detailed engineering or working demonstration, and very hand-wavy cost estimates.
  - deleted 13y ago
    [deleted]
- dgudkov 13y ago
  Currently SpaceX doesn't offer significantly lower LEO delivery costs -- they are on par with Ukrainian/Russian space programs [1]. [1] http://en.wikipedia.org/wiki/Comparison_of_orbital_launch_systems http://en.wikipedia.org/wiki/Comparison_of_orbital_launch_sy...
  - Retric 13y ago
    The Falcon 9 is the cheapest Medium sized launch vehicle it's more expencive to LEO per LB than a heavy launch system or retrofitting old ICBM's. However, we are considering US construction costs and SpaceX spent far less on R&D and spends less on construction than any US equivalents.
akjj 13y ago
> This is obvious from the kind of nitpicking that goes on (no references! 4.37 m/s^2 is the maximum motion sickness possible because an accredited expert proposed it; I've never seen 4.9 m/s^2, but it's surely a barf comet!) This isn't nitpicking. Dealing with the acceleration around curves is going to be a problem for any transit system and at higher speeds it becomes a bigger problem. Unlike bathrooms, this is going to be intrinsic to any system that carries human beings. As the author points out that the hyperloop proposal has significantly higher acceleration than any other high-speed system that he knows about. So, how did the hyperloop designers decide that 4.9 m/s^2 would be safe? Did they find some study which tested this level of acceleration on average people? Did they conduct their own study which overturned conventional wisdom? Did they look at the research which led to the 4.37 m/s^2 figure and determine that it was fatally flawed? This is a critical issue and if the designers don't explain themselves, then it's fair to assume they made it up. The hyperloop proposal contains innovative elements (air suspension in evacuated tubes) and elements which are essentially common with many other transit systems (viaducts, human passengers). The designers deserve credit for the former, but they can't sweep the details of the latter under the rug. The point of references is not stylistic and not to name-check previous work. The point is that when you're doing something, which has had lots of previous research, you either use that research to justify your claims or you explain why yours will be different. > The really interesting, constructive questions: does this low-pressure air cushion thing really work? what are some factors that we need to explore to determine its true efficiency? Those are interesting questions and if Musk had proposed just the air cushion technology, then that's all we would be talking about. People would build test pieces to validate the technology and then go looking for applications. Instead, Musk choose to also include a specific proposal for a replacement for the LA-SF high-speed rail line and to estimate the costs at a tenth as much. That's what got the most media attention and so that's the aspect the OP chose to criticize. BTW, you seem to be implying that the OP is a civil engineer or a transportation engineer with an axe to grind, but he's just an amateur and if you look at his other posts you'll see that he has a lot of concerns for reducing the costs of infrastructure projects.
- zeteo 13y ago
  I agree that it's important to talk about motion sickness. I was pointing out that the way the article deals with it (remarking that the proposed system may involve 12% higher lateral accelerations than HSR, and instantly dismissing it as a "barf ride") is inadequate. Here are a few questions that I don't know the answer to, but seem a lot more interesting: - Do we have studies that estimate the effect of lateral acceleration on motion sickness? What do they indicate (e.g. 0.1% of passengers get it at 4 m/s^2, 2% at 5 m/s^2 etc.)? - To what extent is motion sickness in HSR comparable to the proposed system? Are the differences (no outside visibility, different vibrations model, possibly different seating) significant and if so how? - To what extent do potential passengers care about motion sickness? Has anyone compared cost and convenience trade-offs for systems with different expectations of motion sickness e.g. ferry vs. train? How comfortable are passengers with self-medication in such contingencies? Etc. And motion sickness is only one of hundreds of possible serious weaknesses in this project. But this is inherent in anything that hasn't been tried before; anyone can think of hundreds of ways in which it can go wrong. Does this mean we should never work on anything that isn't fully proven?
Anechoic 13y ago
the criticism amounts almost entirely to basic arithmetic and comparisons to existing systems that are built on rather different principles. But many of most important (and show-stopping) principles involved are the same, and those are what tend to cause delays and increase costs - things like running into unexpected geology, dealing with NIMBY's, the eminent domain process and so on. He seems to think that, in between, his colleagues have been perfecting the fine forms of the art and polishing its many facets. They (we) are. Want to see for yourself? Go to the Transportation Research Board annual meeting in Washington D.C.: http://www.trb.org/AnnualMeeting2014/AnnualMeeting2014.aspx http://www.trb.org/AnnualMeeting2014/AnnualMeeting2014.aspx Except feats that were once fairly common, such as building the Hoover Dam under budget and two years ahead of schedule [1], are in the realm of the mythical these days. You can say the same about the original elevated Boston Artery, the 19th century railroads, etc. The biggest difference between the mega-projects of old and today involve 1) the environmental process and 2) commitments to worker safety. It's fairly easy to build a project quickly when you don't care about splitting neighborhoods, killing/maiming workers and contaminating soil. The environmental process in particular has been a double-edged sword - it's done well in protecting the environment and communities, but it also provides means for anyone who doesn't like any facet of a project to significanty delay (or kill) it.
- zeteo 13y ago
  >The biggest difference between the mega-projects of old and today involve 1) the environmental process and 2) commitments to worker safety. I don't see why environmental and safety considerations are such big unknowns, I think we have a pretty good handle on both by now. Are they factoring to build it with pollution and no safety when they estimate the cost and schedule these days? In fact, if you read about the history of Hoover Dam there were a number of these things that they weren't legally mandated to do back then, but did them anyway. For instance, workers were offered employer-based health insurance (an arrangement that later evolved into what we know today as Kaiser Permanente).
  - Anechoic 13y ago
    I think we have a pretty good handle on both by now In terms of a specific project, not really. Look at everything that goes into an environmental study: watershed/water quality, affected wildlife/endangered species, noise & vibration, soil contamination, archaeological issues, visual impacts, rodent/pests, etc, etc. On top of that, you have to consider the effects of all of those areas during construction and ongoing operations for 20+ years. And that doesn't even account for NIMBY issues. When you're getting into the details of a specific project, it can quickly become overwhelming, especially if you have people who may be philosophically opposed to the project hammering you with those issues time and time again. Are they factoring to build it with pollution and no safety when they estimate the cost and schedule these days? When you look at a project at a high level, you make general assumptions, but as you get more detailed and you know specifically what kind of equipment Take for example, tunneling: At the start of a project, your best information tells you that the sand down to 70ft below grade is clay, so you make your cost and construction estimates using this assumption. You get into detailed design and send drill crews out to collect sample borings and you find out that in much of the area where you assumed sand, you actually have bedrock coming up to 10ft below grade. Now you're plans have to change - instead of doing cut-and-cover tunneling everywhere, you have to blast in some sections, which means having to get a blasting contractor, deal with protecting nearby structures, changing traffic patterns to allow for the blasting etc. In the old days, the project would have just blasted, and if someone's foundation got cracked in the process, too bad. Today that won't fly. edit: just saw your edit In fact, if you read about the history of Hoover Dam there were a number of these things that they weren't legally mandated to do back then, but did them anyway. Compare the number of people killed at the Hoover Dam project compared with the number killed during the Big Dig.
moogleii 13y ago
He definitely seemed to have a chip on his shoulder with a lot of unnecessary backhanded comments, and many engineers do suffer from saying "no" too often, but I do think he raised several points that are applicable to the Hyperloop. Until someone invents anti-gravity, g-forces and other traditional physics problems are going to be a factor. I've been in a sustained half g turn. It's not uncomfortable, but it's not exactly old person friendly, either (in simplistic terms, take half your body weight and imagine that much force pushing you laterally). You'll want bucket seats. And I did not know the Hyperloop would not actually go into LA proper. That's a significant difference to me. That last leg into LA is where a lot of the traffic trauma happens, the part I would most want to avoid. Ultimately both "sides" need to work with each other. The entrepreneur pushing the envelope, and the engineer making sure things are feasible.
dragonwriter 13y ago
> Except feats that were once fairly common, such as building the Hoover Dam under budget and two years ahead of schedule Buildng projects on the scale of the Hoover Dam (whether under budget and ahead of schedule or not) were never "fairly common".

by zeteo 13y ago

Retric 13y ago

I would add he completely ignores the fact he runs a SpaceX which has significantly under cut a long established industry. If you look at his numbers there Basicly estimates for actual costs before padding where large contractors pad construction costs as much as possible because that's how they maximize proffits.

mjn 13y ago
SpaceX is based on a fairly different principle, of taking proven designs from the past, updating them, and building them for less. For example SpaceX's Grasshopper VTVL is following in the footsteps of the 1990s McDonnell Douglas DC-X, not some kind of completely untested idea. He isn't taking a previously speculative technology idea, like a space elevator or something, and trying to build it. An analog here would be if Musk had a proposal to take an existing, working mode of transit (at least working in prototype) and build it for less. But the current proposal is more like hard sci-fi: goes into enough depth to be back-of-the-envelope plausible, but no detailed engineering or working demonstration, and very hand-wavy cost estimates.
- deleted 13y ago
  [deleted]
dgudkov 13y ago
Currently SpaceX doesn't offer significantly lower LEO delivery costs -- they are on par with Ukrainian/Russian space programs [1]. [1] http://en.wikipedia.org/wiki/Comparison_of_orbital_launch_systems http://en.wikipedia.org/wiki/Comparison_of_orbital_launch_sy...
- Retric 13y ago
  The Falcon 9 is the cheapest Medium sized launch vehicle it's more expencive to LEO per LB than a heavy launch system or retrofitting old ICBM's. However, we are considering US construction costs and SpaceX spent far less on R&D and spends less on construction than any US equivalents.

akjj 13y ago

> This is obvious from the kind of nitpicking that goes on (no references! 4.37 m/s^2 is the maximum motion sickness possible because an accredited expert proposed it; I've never seen 4.9 m/s^2, but it's surely a barf comet!) This isn't nitpicking. Dealing with the acceleration around curves is going to be a problem for any transit system and at higher speeds it becomes a bigger problem. Unlike bathrooms, this is going to be intrinsic to any system that carries human beings. As the author points out that the hyperloop proposal has significantly higher acceleration than any other high-speed system that he knows about. So, how did the hyperloop designers decide that 4.9 m/s^2 would be safe? Did they find some study which tested this level of acceleration on average people? Did they conduct their own study which overturned conventional wisdom? Did they look at the research which led to the 4.37 m/s^2 figure and determine that it was fatally flawed? This is a critical issue and if the designers don't explain themselves, then it's fair to assume they made it up. The hyperloop proposal contains innovative elements (air suspension in evacuated tubes) and elements which are essentially common with many other transit systems (viaducts, human passengers). The designers deserve credit for the former, but they can't sweep the details of the latter under the rug. The point of references is not stylistic and not to name-check previous work. The point is that when you're doing something, which has had lots of previous research, you either use that research to justify your claims or you explain why yours will be different. > The really interesting, constructive questions: does this low-pressure air cushion thing really work? what are some factors that we need to explore to determine its true efficiency? Those are interesting questions and if Musk had proposed just the air cushion technology, then that's all we would be talking about. People would build test pieces to validate the technology and then go looking for applications. Instead, Musk choose to also include a specific proposal for a replacement for the LA-SF high-speed rail line and to estimate the costs at a tenth as much. That's what got the most media attention and so that's the aspect the OP chose to criticize. BTW, you seem to be implying that the OP is a civil engineer or a transportation engineer with an axe to grind, but he's just an amateur and if you look at his other posts you'll see that he has a lot of concerns for reducing the costs of infrastructure projects.

zeteo 13y ago
I agree that it's important to talk about motion sickness. I was pointing out that the way the article deals with it (remarking that the proposed system may involve 12% higher lateral accelerations than HSR, and instantly dismissing it as a "barf ride") is inadequate. Here are a few questions that I don't know the answer to, but seem a lot more interesting: - Do we have studies that estimate the effect of lateral acceleration on motion sickness? What do they indicate (e.g. 0.1% of passengers get it at 4 m/s^2, 2% at 5 m/s^2 etc.)? - To what extent is motion sickness in HSR comparable to the proposed system? Are the differences (no outside visibility, different vibrations model, possibly different seating) significant and if so how? - To what extent do potential passengers care about motion sickness? Has anyone compared cost and convenience trade-offs for systems with different expectations of motion sickness e.g. ferry vs. train? How comfortable are passengers with self-medication in such contingencies? Etc. And motion sickness is only one of hundreds of possible serious weaknesses in this project. But this is inherent in anything that hasn't been tried before; anyone can think of hundreds of ways in which it can go wrong. Does this mean we should never work on anything that isn't fully proven?

Anechoic 13y ago

the criticism amounts almost entirely to basic arithmetic and comparisons to existing systems that are built on rather different principles. But many of most important (and show-stopping) principles involved are the same, and those are what tend to cause delays and increase costs - things like running into unexpected geology, dealing with NIMBY's, the eminent domain process and so on. He seems to think that, in between, his colleagues have been perfecting the fine forms of the art and polishing its many facets. They (we) are. Want to see for yourself? Go to the Transportation Research Board annual meeting in Washington D.C.: http://www.trb.org/AnnualMeeting2014/AnnualMeeting2014.aspx http://www.trb.org/AnnualMeeting2014/AnnualMeeting2014.aspx Except feats that were once fairly common, such as building the Hoover Dam under budget and two years ahead of schedule [1], are in the realm of the mythical these days. You can say the same about the original elevated Boston Artery, the 19th century railroads, etc. The biggest difference between the mega-projects of old and today involve 1) the environmental process and 2) commitments to worker safety. It's fairly easy to build a project quickly when you don't care about splitting neighborhoods, killing/maiming workers and contaminating soil. The environmental process in particular has been a double-edged sword - it's done well in protecting the environment and communities, but it also provides means for anyone who doesn't like any facet of a project to significanty delay (or kill) it.

zeteo 13y ago
>The biggest difference between the mega-projects of old and today involve 1) the environmental process and 2) commitments to worker safety. I don't see why environmental and safety considerations are such big unknowns, I think we have a pretty good handle on both by now. Are they factoring to build it with pollution and no safety when they estimate the cost and schedule these days? In fact, if you read about the history of Hoover Dam there were a number of these things that they weren't legally mandated to do back then, but did them anyway. For instance, workers were offered employer-based health insurance (an arrangement that later evolved into what we know today as Kaiser Permanente).
- Anechoic 13y ago
  I think we have a pretty good handle on both by now In terms of a specific project, not really. Look at everything that goes into an environmental study: watershed/water quality, affected wildlife/endangered species, noise & vibration, soil contamination, archaeological issues, visual impacts, rodent/pests, etc, etc. On top of that, you have to consider the effects of all of those areas during construction and ongoing operations for 20+ years. And that doesn't even account for NIMBY issues. When you're getting into the details of a specific project, it can quickly become overwhelming, especially if you have people who may be philosophically opposed to the project hammering you with those issues time and time again. Are they factoring to build it with pollution and no safety when they estimate the cost and schedule these days? When you look at a project at a high level, you make general assumptions, but as you get more detailed and you know specifically what kind of equipment Take for example, tunneling: At the start of a project, your best information tells you that the sand down to 70ft below grade is clay, so you make your cost and construction estimates using this assumption. You get into detailed design and send drill crews out to collect sample borings and you find out that in much of the area where you assumed sand, you actually have bedrock coming up to 10ft below grade. Now you're plans have to change - instead of doing cut-and-cover tunneling everywhere, you have to blast in some sections, which means having to get a blasting contractor, deal with protecting nearby structures, changing traffic patterns to allow for the blasting etc. In the old days, the project would have just blasted, and if someone's foundation got cracked in the process, too bad. Today that won't fly. edit: just saw your edit In fact, if you read about the history of Hoover Dam there were a number of these things that they weren't legally mandated to do back then, but did them anyway. Compare the number of people killed at the Hoover Dam project compared with the number killed during the Big Dig.

moogleii 13y ago

He definitely seemed to have a chip on his shoulder with a lot of unnecessary backhanded comments, and many engineers do suffer from saying "no" too often, but I do think he raised several points that are applicable to the Hyperloop. Until someone invents anti-gravity, g-forces and other traditional physics problems are going to be a factor. I've been in a sustained half g turn. It's not uncomfortable, but it's not exactly old person friendly, either (in simplistic terms, take half your body weight and imagine that much force pushing you laterally). You'll want bucket seats. And I did not know the Hyperloop would not actually go into LA proper. That's a significant difference to me. That last leg into LA is where a lot of the traffic trauma happens, the part I would most want to avoid. Ultimately both "sides" need to work with each other. The entrepreneur pushing the envelope, and the engineer making sure things are feasible.

dragonwriter 13y ago

> Except feats that were once fairly common, such as building the Hoover Dam under budget and two years ahead of schedule Buildng projects on the scale of the Hoover Dam (whether under budget and ahead of schedule or not) were never "fairly common".