Here's a description of the closest guess Elon has seen so far. https://twitter.com/John_Gardi/status/356798172842049536
Neat idea but I just don't see how it's cheaper than a high speed rail project?
Elon Musk to publish hyperloop design by August
141–150 of 175 posts
Re: Elon Musk to publish hyperloop design by August
#142If this is, as it sounds, a new public transport system, it surprises me a little that he would prefer to develop it in the US. Attitudes towards public transport in general seem more favourable in the EU, Japan, China and South Korea. Perhaps I'm missing something, but I imagine getting such a system built in the EU (for example) would be easier than the US. Then again, Musk has been building a reputation with law-m…
I think US's opinions about public transportation is based on rational comparison. Taking the bus takes more time than taking a car, and is a less desirable environment. Our train system is optimized for freight, and has no cost or time benefit over just driving. Countries which have high amounts of public transportation tend to have higher gas prices and population density. It becomes more cost and time effective in…
Rational comparison or desirability of environments would take into account the likelihood of an hour on a decent bus allowing you to get more done (or more sleep) than 45 minutes of focusing attention on the car in front of you...
Re: Elon Musk to publish hyperloop design by August
#143Earlier quoted context omitted.
Is it an enclosed tube or just a special road that cars float on?
Enclosed tunnel: "air column" is a give-away. This is essentially a vac-train, except instead of a vacuum, the air in the tube is propelled along with the pod. There will be friction, but only between the air and the inside of the tube. I imagine there'll need to be some kind of "repeaters" to counter-act energy loss, but with so little loss, they could probably be solar-powered; which I think Elon alluded to.
Only between the air and the inside of the tube? Instead of a 100m train with air flowing around it, you get air at length of the track moving along the inside of the tube at the same speed.
I know as good as nothing of aerodynamics, but even if you get the latter flow perfectly laminar, I doubt it is a net win, as the contact area is 1000 times as large or so. But educate me.
Also, when you move cars into and out of the tunnel with the rotating air, you must take care not to 'plug' that air flow. Even if you do that only partly, there will be a pressure front (read: noise, vibrations, energy loss); each car will, for a moment get a sidewind at the speed of the train.
Here is a variant that, to me, makes more sense: it is not a vacuum, but they use the motion of the cars to push air out of the tunnel, so that air pressure drops. I don't have the vaguest idea how that would work, but if you can get it to work, it would be a nice trick.
Re: Elon Musk to publish hyperloop design by August
#144Here's a description of the closest guess Elon has seen so far. https://twitter.com/John_Gardi/status/356798172842049536
To save someone else digging through 4 layers of Twitter/Twitpic attribution and "full size" buttons: http://twitpic.com/cw4pqb/full
That looks like a more elaborate version of something I thought of as a kid, which was basically a vacuum tube going all around the world (one big torus if you will) with carts on super conductive magnets. I was thinking mainly of connecting Tokyo and New York and some place or other in Europe. Cart drives into the station, station gets sealed off and air pumped into it, then passengers leave and board, the doors get closed and the station sealed, then the thing speeds off at a gazillion miles per hour. Yay! Of course you'd have to start braking long before arrival, but the idea wasn't really about saving time (I could not possibly have anticipated how pampered and stupid grown ups are), it was mostly about saving energy, the idea of near zero friction just fascinated me. Though I was never sure if cooling the magnets and keeping the vacuum up wouldn't be more expensive than the energy saved.
But all that aside: bleh to passengers, think freight! If it's too complicated for people, because they won't use it if it takes as long as taking a plane... even though being a passenger on just one airplane ride is like riding a fat car for a whole year (give or take, it's nuts either way)... then automate it and use it for cargo. Especially since in that case and for a lot of products the vacuum wouldn't matter, the cargo could just ride in open carts and get picked up by robotic arms. Heck, you might even just throw it on while it's moving, and even use hooks to get cargo off without stopping the cart at all. This might seem too tricky... until you realize what marvels are going on in a bog standard HD these days, right? (though I remember a similar invention for passenger buses from MAD Magazine: something about spring-loaded seats haha)
Re: Elon Musk to publish hyperloop design by August
#145Earlier quoted context omitted.
I think US's opinions about public transportation is based on rational comparison. Taking the bus takes more time than taking a car, and is a less desirable environment. Our train system is optimized for freight, and has no cost or time benefit over just driving. Countries which have high amounts of public transportation tend to have higher gas prices and population density. It becomes more cost and time effective in…
Rational comparison or desirability of environments would take into account the likelihood of an hour on a decent bus allowing you to get more done (or more sleep) than 45 minutes of focusing attention on the car in front of you...
I was speaking more about longer distances than just 45 minutes. The initial proposal seems to be more about longer distance traveling over daily commutes. My experience with bus trips is them being 30% to 60% longer travel times for more money than it would cost in gas if driving a car.
Re: Elon Musk to publish hyperloop design by August
#146Here's a description of the closest guess Elon has seen so far. https://twitter.com/John_Gardi/status/356798172842049536
Neat idea but I just don't see how it's cheaper than a high speed rail project?
Agreed -- seems like you'd have higher construction costs, higher energy requirements, and similar right-of-way concerns.
Re: Elon Musk to publish hyperloop design by August
#147Earlier quoted context omitted.
I think US's opinions about public transportation is based on rational comparison. Taking the bus takes more time than taking a car, and is a less desirable environment. Our train system is optimized for freight, and has no cost or time benefit over just driving. Countries which have high amounts of public transportation tend to have higher gas prices and population density. It becomes more cost and time effective in…
Rational comparison or desirability of environments would take into account the likelihood of an hour on a decent bus allowing you to get more done (or more sleep) than 45 minutes of focusing attention on the car in front of you...
Hmm, then I've never been on a "decent" bus (used buses in LA and a little in Boston). They never seemed like good environments for work. In LA particularly, even if it weren't for all the idiots playing music on their earphones that's clearly audible from over a yard away, there's these stupid TV programs running. And for most of the trips I needed them for (before I could drive), they took 3 times as long as driving. We make decisions based on the actual options, not what "decent" options would be. Driving is definitely a better deal.
Re: Elon Musk to publish hyperloop design by August
#148Earlier quoted context omitted.
Enclosed tunnel: "air column" is a give-away. This is essentially a vac-train, except instead of a vacuum, the air in the tube is propelled along with the pod. There will be friction, but only between the air and the inside of the tube. I imagine there'll need to be some kind of "repeaters" to counter-act energy loss, but with so little loss, they could probably be solar-powered; which I think Elon alluded to.
Only between the air and the inside of the tube? Instead of a 100m train with air flowing around it, you get air at length of the track moving along the inside of the tube at the same speed. I know as good as nothing of aerodynamics, but even if you get the latter flow perfectly laminar, I doubt it is a net win, as the contact area is 1000 times as large or so. But educate me. Also, when you move cars into and out of…
I know next to nothing as well, but I think that perfectly laminar flow would be worst case. However if the inside of the tube had divots like a golf ball, the slower-moving turbulent vortices would push the faster-moving laminar stream away from the walls, so that the boundary layer doesn't impact the velocity of the central air column nearly as much.
Again: "I think..." I'd be happy if someone who knows more would chime in to tell me why I'm wrong. :-)
Re: Elon Musk to publish hyperloop design by August
#149I'm always surprised that more billionaires don't try interesting off the wall projects when they have so much money. What's the fun of having it, if you can't have the occasional mad scientist moment.
In Australia we have Clive Palmer. He's building a replica Titanic and a mechatronic Jurassic Park. And now has his own Political party named after himself with candidates in every seat in the country.
Re: Elon Musk to publish hyperloop design by August
#150Here's a description of the closest guess Elon has seen so far. https://twitter.com/John_Gardi/status/356798172842049536
Neat idea but I just don't see how it's cheaper than a high speed rail project?
My only guess on this is max capacity. Theoretically if the tube were large enough you could run a few of these a day and carry thousands of people on each one. If you can get the energy consumed per passenger way down, then costs may decrease and a ticket could be much less expensive.
If you could travel hundreds of miles in a half hour, you might make a lot more trips. Changing the cost structure and timing dramatically would change the way people think about long distance travel from something you do once in a while to being as common as going across town for an afternoon.
Obviously this is all far-fetched given today's technology, but I'm just letting myself daydream.