Really, Elon?

[Capt Worley PE]

In a blog post today, Elon Musk revealed plans for an alpha version of his much-anticipated Hyperloop, an innovative transportation system that would move passengers from Los Angeles to San Francisco in less than 30 minutes. According to the plans (PDF), the Hyperloop would transport passengers in aluminum pods traveling up to 800mph, mostly following the route of California's I-5. The estimated cost would be $6 billion for passenger-only model, or $10 billion for a larger model capable of transporting cars. On a following conference call, Musk said he expected a prototype unit might take only three or four years to complete given the right project leader, including a couple years to acclimate themselves to the project. "If it was my top priority, I could probably get it done in one or two years."

http://www.theverge.com/2013/8/12/4614940/elon-musk-reveals-plans-for-high-speed-hyperloop

Ahem.....

In 1869, Alfred Ely Beach and his Beach Pneumatic Transit Company of New York began constructing a pneumatic subway line beneath Broadway. (Beach had earlier demonstrated the basic system at the American Institute Exhibition in 1867.) Funneled through a company he set up,

Beach put up $350,000 of his own money to bankroll the project.[1] Built in only 58 days,[2] its single tunnel, 312 feet (95 m) long, 8 feet (2.4 m) in diameter, was completed in 1870 and ran under Broadway from Warren Street to Murray Street.[3]

With no initial political support for his project, he started the project claiming he was building postal tubes. The initial permit was to install a pair of smaller postal tubes below Broadway but was later amended to allow the excavation of a single large tunnel wherein the smaller tubes could reside.[4]The exact location of the tubes was determined during construction by compass and survey as well as verified by driving jointed rods of iron up through the roof of the tunnel to the pavement.[5] The line was built as a demonstration of a pneumatic transit system, open to the public with fares donated to charity. Proceeds of the 25 cent admission went to the Union Home and School for Soldiers' and Sailors' Orphans.[6]

It remained little more than a curiosity, running only a single car on its one-block-long track to a dead-end at its terminus. (Passengers would simply ride out and back, to see what the proposed subway might be like.) During its first two weeks of operation, the Beach Pneumatic Transit sold over 11,000 rides with 400,000 rides provided during its first year of operation.[7][8]

http://en.wikipedia.org/wiki/Beach_Pneumatic_Transit

Also: http://www.oobject.com/category/pneumatic-trains/

 

[YMZ PE]

"Get the scientists working on the tube technology, immediately. Chop, chop, let's go." - Tenacious D

 

[Master slacker]

I read the white paper last night. Seems pretty damn cool, but it's still 20 years out from reality. He would still have to garner the support for a pilot project and THEN sell it to the people government.

 

[snickerd3]

i still wouldn't want to be one of first to try it

 

[wilheldp_PE]

One of my other engineer buddies pointed out a glaring flaw in this system. The cars are brought up to speed and slowed down by linear accelerators at each station, meaning that there is no way to adjust speed in between stations. So what happens if an air compressor goes out, or something else goes wrong between stations that causes a car to slow or stop? You have cars travelling at 800 mph, spaced 30 seconds apart. If your car stops and the initial deceleration doesn't kill you, the 800 mph car behind you will kill you within the next 30 seconds.

 

[ALBin517]

You have cars travelling at 800 mph, spaced 30 seconds apart. If your car stops and the initial deceleration doesn't kill you, the 800 mph car behind you will kill you within the next 30 seconds.

I believe the car behind would kill you in a time GREATER than 30 seconds, not "within the next 30 seconds."

 

[ALBin517]

It's good to see Elon has stayed busy since divorcing Tiger.

 

[envirotex]

@wil: At least you probably wouldn't feel anything since you would be turned into instantaneous soup.

 

[Exception Collection]

From the Businessweek story: “There’s an emergency brake,” he says. “Generally, though, the safe distance between the pods would be about 5 miles, so you could have about 70 pods between Los Angeles and San Francisco that leave every 30 seconds. It’s like getting a ride on Space Mountain at Disneyland.”

You have cars travelling at 800 mph, spaced 30 seconds apart. If your car stops and the initial deceleration doesn't kill you, the 800 mph car behind you will kill you within the next 30 seconds.

I believe the car behind would kill you in a time GREATER than 30 seconds, not "within the next 30 seconds."

No, because the deceleration isn't instantaneous. At 800 mph, slowing down in a way that doesn't kill you would require a deceleration of less than 100g (which is survivable, by race car drivers, but most humans aren't race car drivers). At 800 mph, that would take just over a third of a second. So a crash is survivable, though not pretty. Assuming an interval of 30 seconds (which is a bit much, I think) and standard movement rates, the second vehicle would strike the first at 30s-.36s.

The emergency brake, on the other hand, likely spreads that over a 25 second or so stopping time; let's use 20 seconds as a reasonable value that gives some leeway. That'd be 40 mph/sec, or less than 2g (1g = 21.93 mph/s) over 20 seconds, roughly equivalent to stopping a car going 44 mph in a second. Assuming reasonable safety equipment, perfectly survivable.

 

[RIP - VTEnviro]

10 bucks says you still won't be able to get anywhere from where I live.

 

[csb]

It's good to see Elon has stayed busy since divorcing Tiger.

:appl:

If I can't send change through the pneumatic tube at the bank, I'm not putting my body on one of these.

 

[knight1fox3]

^ What's wrong with sending a little change through the tube? It all got there didn't it?

 

[envirotex]

This is pretty cool too...It must be nice to have a billion dollars to use to build rockets in your backyard.