MIT Team Tops Hyperloop Design Competition (google.com)

The Dallas Morning News reports that a team from MIT has topped competitors from around 100 universities around the world at a competition held on the campus of Texas A&M by presenting a workable design vision for Elon Musk's dream of a hyperloop. The hyperloop concept, mentioned several times before on Slashdot, involves rapidly shuffling passenger pods through 12-foot-wide tubes evacuated of air, and would mean terrestrial transport at speeds topping those of commercial air travel. From the Morning News article: Delft University of Technology from The Netherlands finished second, the University of Wisconsin third, Virginia Tech fourth and the University of California, Irvine, fifth. The top teams will build their pods and test them at the world's first Hyperloop Test Track, being built adjacent to SpaceX's Hawthorne, Calif., headquarters.

Comments

Nature Abhors a Vacuum

[ebonum]

I think this hyperloop is going to crash into the harsh realities of dealing with a vacuum.
a) It takes a huge amount of energy to pull a good vacuum. This thing needs to be at 0.02 psi. Vacuum pumps are really inefficient. They mostly take electricity and generate lots of heat.
b) Running the pumps is going to cost. Vacuum pumps burn out/need maintenance.
c) 0.02 psi? That translates into a HUGE amount of force trying to crush the tube. 14 lbs/ square inch. It adds up QUICK. Better hope some 13 year old doesn't think it would be funny to put an M-80 on this thing. It might implode and kill anyone in the pod.
d) Ever to try keep a vacuum? Good luck finding all the little leaks in the seals over X miles of this tube. Getting it evacuated once will be difficult. Now try to keep it sealed for a year. You have the stress of the pods flying through this thing. You have heating and cooling cycles every 24 hours.

It will make a awesome science project for some students spending lots of other people's money.

Re:Nature Abhors a Vacuum

[Anonymous Coward]

True. IMO it needs to be double or tri-walled with intermediate structure to be anywhere near feasible.

Re:Nature Abhors a Vacuum

[Rei]

Right, because inch-thick steel (hyperloop) just collapses like a can.

Seriously, have you run the numbers on how much force it takes to bend inch-thick steel? Even in the event of a bomb-induced rupture it wouldn't collapse like that, it'd simply give just enough to let air in.

Maintaining a vacuum is easier than maintaining high pressures, and we make and use long high pressure pipes all the time.

Re: Nature Abhors a Vacuum

[Rei]

Being borne by the mass of nearly 100 Eiffel towers, in a form naturally resistant to pressure (a cylinder).

Seriously, we deal with far more extreme pressure differentials in pipelines all the time. There's absolutely nothing exotic about the proposed pipeline. It's fairly large, but with nearly inch-thick steel (20-23mm), buckling isn't even close to a risk; the thickness of steel required for a 2,23m cylindrical shell to not buckle is a small fraction of that. The thickness of the tube is more governed by the issues of loading between columns than by the internal pressure.

Re:Nature Abhors a Vacuum

[Rei]

CA HSR is a $70B project. Hyperloop is a $6B project. Re: throughput: Hyperloop pods launch every 2 minutes during off-peak (30 seconds during peak) with 28 passengers, aka minimum of 20k per day, up to 80k per day depending on demand. HSR trains leave every 5-10 minutes with 450 passengers; they're ultimately hoping for 110k daily ridership, but it's expected to begin at well less than that (and critics think they're overestimating ridership by as much as 70%, but that's neither here nor there)

In short, HSR is higher throughput (it's designed to service a larger area), but not by the sort of margin that justifies the order-of-magnitude budget difference. It's also significantly slower, significantly more energy consuming, and significantly more cost per ride. Now, you can doubt Hyperloop numbers - that's fine. But that's not what this conversation is about: this conversation is about what the point of Hyperloop is: far better throughput per dollar at far better passenger cost, energy consumption, and trip time. That's the point. Whether they can pull it off, that's something they have yet to prove.

Honestly, I personally don't like how Hyperloop was set up as a competitor to HSR. Because it's really something new, something in-between high speed rail and air travel. I think they would have made far fewer "enemies" had they presented their initial pilot route as LA to Las Vegas. Probably could have gotten a lot of investment money from casino operators that way, too.