Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Hyperloop

spacex.com

Post reply on HN
Print view View original

191–200 of 983 posts

Re: Hyperloop

#191

Post by mason55 »

potatolicious wrote: post #139
r00fus wrote: post #82

Earlier quoted context omitted.

What happens currently on a high-speed rail system? I suppose there's a lavatory in the HSR (e.g.: France's TGV).

Currently you get up and go to the bathroom at the end of the car. I've only had time to skim the full PDF, but there's something about experiencing 0.5g of acceleration - unsure if that is a constant or if that is simply right at the very beginning. If you're going to experience 0.5g of acceleration over a prolonged period, letting passengers get up and move about is going to be a bad idea. It also doesn't look like…

> unsure if that is a constant or if that is simply right at the very beginning.

If the top speed is 700mph then you'd have 142 seconds of 0.5 g acceleration to get to top speed. How often you'd be accelerating or decelerating would depend on how many intermediate stations there are.

Re: Hyperloop

#192

Post by typon »

tptacek wrote: post #131
dvmmh wrote: post #108

Earlier quoted context omitted.

No toilets on commuter buses either and people ride them 45minutes to 1+ hours everyday with no issues. You're stuck in the "long trip" "it's like a train" framework. It is neither.

Commuter buses stop regularly.

Taxi rides, flights, buses all have 30 min rides FREQUENTLY and no washroom facilities in those 30 min.

Re: Hyperloop

#193

Post by cma »

aaronmarks wrote: post #75
chrismealy wrote: post #49

So, it's a two-lane highway where the cars are 5 miles apart? How many people will be able to use this thing?

From the report: "...with capsules departing as often as every 30 seconds from each terminal and carrying 28 people each. This gives a total of 7.4 million people each way that can be transported each year on Hyperloop."

Eventually hits up against this problem:

http://books.google.com/books?id=DenWKRgqzWMC&pg=PA67&lpg=PA...

Re: Hyperloop

#194

Post by frenchy »

marssaxman wrote: post #149
popopje wrote: post #70

Earlier quoted context omitted.

what happens when you develop unexpected gastric issues mid-30 minute journey?

Same thing that happens if you develop unexpected gastric issues during a 30 minute plane flight, I'd imagine, since you'd spend the whole time strapped in for take-off and then landing.

I'm pretty sure in this case they would let you go to the bathroom.

Re: Hyperloop

#195

Post by outworlder »

macinjosh wrote: post #127

For all of you whose panties get wet at the sound of Elon Musk's name Hyperloop is essentially just Aérotrain in a tube: https://en.wikipedia.org/wiki/A%C3%A9rotrain This guy isn't really a genius, he's just rich.

Not really. There are similarities in the car's design, just as there are similarities among airplanes.

Aérotrain is a magnetic levitation train, Hyperloop does not use magnetic levitation. Read the PDF.

Re: Hyperloop

#196

Post by stcredzero »

axus wrote: post #176
mortenjorck wrote: post #160

Earlier quoted context omitted.

I'm not claustrophobic, but this image ever so slightly terrified me: http://i.imgur.com/lGD9bUP.png I have to wonder, would making the capsule the size of a small subway car completely destroy the economics of it?

It's also scary that the passengers would suffocate if the life support system failed.

No different than planes.

Re: Hyperloop

#197

Post by ansible »

clarkmoody wrote: post #144

I love this concept! My main concern is the air-bearing suspension system. Barring very high flow rates, the fly-height of an air-bearing system is very small. Some systems[1] fly at 5 microns, for instance. That being the case, any sort of particulate or imperfections in the tube will cause the air-bearing to 'land' with a large amount of friction. Perhaps this is alright if you're already going 700mph, but it would…

As an aside, I would like to see trade studies done on filling the tube with other gasses whose speed of sound is much higher than air's, allowing the capsules to travel even faster before shocks begin to form.

I don't think this is a good idea for production use, because then you have to worry about air leaks to/from the passenger compartment.

As it is, you still have to guard against explosive decompression for the passengers.

Re: Hyperloop

#198

Post by CamperBob2 »

axus wrote: post #176
mortenjorck wrote: post #160

Earlier quoted context omitted.

I'm not claustrophobic, but this image ever so slightly terrified me: http://i.imgur.com/lGD9bUP.png I have to wonder, would making the capsule the size of a small subway car completely destroy the economics of it?

It's also scary that the passengers would suffocate if the life support system failed.

Not that different from a commercial aircraft in that regard. Loss of pressurization is a serious emergency in both cases.

Re: Hyperloop

#199

Post by Osmium »

Reading the entire PDF is highly recommended; it contains a surprising amount of answers already (including many to comments below).

I think, if anything, safety aspects haven't been sufficiently explored in the pdf. I'm quite happy to believe it's safer than other modes of transport, but I wouldn't be too quick to overstate it. Also, if anyone can explain what "Tubes located on pylons would limit access to the critical elements of the system." is meant to mean in §4.5.6 I'd be grateful...

Re: Hyperloop

#200

Post by nawitus »

ansible wrote: post #182
acadien wrote: post #80

Earlier quoted context omitted.

But that's at a pressure of 100Pa (1/1000 atm). How much power does it take to maintain a vacuum of 1/1000atm in a tube hundreds of miles long? It seems this point is skipped over in the whitepaper, so perhaps its negligible. Edit: yes I was referring to the power to sustain a vacuum in a leaky system, of course no power is required to maintain a vacuum in a perfectly sealed system :)

How much power does it take to maintain a vacuum of 1/1000atm in a tube hundreds of miles long? It doesn't require any power, if there are no leaks. The power required will be determined by the amount of leakage that is considered tolerable to the system.

There'll certainly be leaks, it's another question how much.
Post reply on HN