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

Hyperloop One Becomes ‘Virgin Hyperloop One’

techcrunch.com

Post reply on HN
Print view View original

211–220 of 517 posts

Re: Hyperloop One Becomes ‘Virgin Hyperloop One’

#211

Post by thearn4 »

JumpCrisscross wrote: post #168

The original Hyperloop paper quotes its design pressure as “about 1/6 the pressure of the atmosphere on Mars” [1]. Martian atmospheric pressure is “about 0.6% of Earth's mean sea level pressure” [2]. So 0.1% of Earth’s surface pressure, or a 1,000:1 pressure change. To put that in perspective, the Boeing 787’s GEnx-2B67, the most powerful GEnx engine variant, generates a 43:1 pressure ratio [3]. To get a sense of the…

Some colleagues of mine also did a short feasibility assessment of the original white paper, and came to some similar conclusions. The propulsion system also made some assumptions about compressor performance that seemed too optimistic compared to existing turbomachinery.

That said, I have not followed closely enough to know if the hyperloop startups out there are following the original conception or if it has significantly evolved or not. I hear that they've ditched the compressor altogether, but that's got to have a pretty big impact on expected speeds.

Re: Hyperloop One Becomes ‘Virgin Hyperloop One’

#212

Post by grw_ »

pavs wrote: post #189
Analemma_ wrote: post #21

Earlier quoted context omitted.

When Musk first said that an LA SF Hyperloop could be built for 1/8th the cost of the equivalent HSR, I chuckled and then waited for the punchline, which still hasn’t arrived. It’s a cool idea and I do want to see more prototypes and feasibility studies, but people need to get off the hype train (no pun intended) and be realistic about the cost.

I don't think Musk want hyperloop to be built above the ground. This is just my own personal opinion, not sure if that's how it's going to work, but in one of his interview (TED? I think), he mentioned one of the reasons for his Boring company, was it would be relatively cheaper to build hyperloop - because the atmospheric pressure will be lower underground - and since you don't have to worry about building large inf…

Why would atmospheric pressure be lower underground?

Re: Hyperloop One Becomes ‘Virgin Hyperloop One’

#213

Post by ant6n »

Pxtl wrote: post #191
ant6n wrote: post #156

Earlier quoted context omitted.

Definitely agree that more, better transit would have a much bigger impact. But I'd say the problem of commuter rail is frequency, coverage station locations, acceleration, level boarding, dwell times etc etc. Given that line speed is dictated by acceleration and dwell times, top speed is really far down the list of priorities. Also, top speed of commuter rail is already up to 200km/h (e.g. https://en.wikipedia.org/w…

I guess it's just my own experience in Ontario - the GO transit trains look like they travel at about 110kph or so, and once you figure in their slow acceleration and frequent stops that means they're quite slow. Outside of the worst part of Toronto rush hour (which is notoriously bad) they're actually slower than the comparable coach bus from my area (Hamilton). The overall average speed is a paltry 50kph. When the…

The average speed is governed by acceleration and dwell time - the issue for GO is lack of electrification (which increases acceleration), and lack of level boarding (which decreases dwell time).

50km/h average is actually quite fast. I mean, a radius 50km from downtown is a huge area already. We have to densify inside that radius, not sprawl people further out because the trains are so fast. This means for example we need more stations, so that more developable land is within walking distance of service.

Re: Hyperloop One Becomes ‘Virgin Hyperloop One’

#214

Post by [deleted] »

KGIII wrote: post #190
austenallred wrote: post #130

Earlier quoted context omitted.

> For someone who has their own always-on Apache I’m just guessing on numbers, but that probably describes <1% of the population. Most people think Apache is a word used only to describe helicopters.

A small point really, but I'm not sure most people would only think it describes helicopters. I am guessing most people would think it is a tribe of Native Americans. I admit that it's just a guess, but it does seem likely. Again, not a major point.

[deleted]

Re: Hyperloop One Becomes ‘Virgin Hyperloop One’

#215

Post by noonespecial »

manigandham wrote: post #161
noonespecial wrote: post #148

Earlier quoted context omitted.

> We (in the USA) can barely build a high-speed rail line effectively We went to the moon. We send car sized rovers to Mars. We certainly can (in the technical sense) build a friggin' train. Its a political problem that keeps us from doing it. So its more like "we won't build high speed rail", and there are plenty of interesting reasons why this is so. The point is that the mystical sounding Hyperloop might be just w…

Sure, it's a combination of political/social/economic factors but "futuristic" doesn't seem to have much impact right now (if it ever really did). NASA's trip to the moon was funded by war motives and we've since had the decline of both the space station and the shuttle programs. It's great to see SpaceX doing new things but there's definitely profits in reducing launch costs (again driven by war and business motives…

Yes airlines are the first thing that spring to mind when I think of wifi, food, and convenience during travel.

Call me an optimist but it's high time for something new to shake things up. I don't care if it's a magic tube train or just some really nice selfdriving busses.

Re: Hyperloop One Becomes ‘Virgin Hyperloop One’

#216

Post by mhermher »

microcolonel wrote: post #207
daemin wrote: post #165

Just as a thought experiment, could the promotion of these "hyperloop" projects be a clever political ploy to misdirect/divert attention and prevent a viable high speed rail network from being built? Elon's main business is electric cars and (one of) Branson's is airlines. So a reasonable competitor to both is fast and cheap(er) public transport along a major travel corridor in the USA. This means that by promoting t…

I think it would be a good idea to make sure the California "high speed" rail program is never funded. It is a terrible idea. As it stands, it would be as slow as conventional rail, redundant with AmTrak, and the most expensive rail line ever built. It would be absolutely devastating for the government's relationship with at least tens of thousands of land owners, hundreds of thousands of home owners, who would see d…

It's not redundant with amtrak. There's no way to get from LA to SD on passenger rail without transferring through busses.

Re: Hyperloop One Becomes ‘Virgin Hyperloop One’

#217

Post by mhermher »

mhermher wrote: post #216
microcolonel wrote: post #207

Earlier quoted context omitted.

I think it would be a good idea to make sure the California "high speed" rail program is never funded. It is a terrible idea. As it stands, it would be as slow as conventional rail, redundant with AmTrak, and the most expensive rail line ever built. It would be absolutely devastating for the government's relationship with at least tens of thousands of land owners, hundreds of thousands of home owners, who would see d…

It's not redundant with amtrak. There's no way to get from LA to SD on passenger rail without transferring through busses.

That should be SF, not SD.

Re: Hyperloop One Becomes ‘Virgin Hyperloop One’

#218

Post by Robotbeat »

JumpCrisscross wrote: post #168

The original Hyperloop paper quotes its design pressure as “about 1/6 the pressure of the atmosphere on Mars” [1]. Martian atmospheric pressure is “about 0.6% of Earth's mean sea level pressure” [2]. So 0.1% of Earth’s surface pressure, or a 1,000:1 pressure change. To put that in perspective, the Boeing 787’s GEnx-2B67, the most powerful GEnx engine variant, generates a 43:1 pressure ratio [3]. To get a sense of the…

Wait, who said that they need to compress the air all the way to Earth pressure?

None of your critique makes sense without that assumption, and nowhere in your post do you say where that comes from.

Re: Hyperloop One Becomes ‘Virgin Hyperloop One’

#219

Post by valas »

microcolonel wrote: post #207
daemin wrote: post #165

Just as a thought experiment, could the promotion of these "hyperloop" projects be a clever political ploy to misdirect/divert attention and prevent a viable high speed rail network from being built? Elon's main business is electric cars and (one of) Branson's is airlines. So a reasonable competitor to both is fast and cheap(er) public transport along a major travel corridor in the USA. This means that by promoting t…

I think it would be a good idea to make sure the California "high speed" rail program is never funded. It is a terrible idea. As it stands, it would be as slow as conventional rail, redundant with AmTrak, and the most expensive rail line ever built. It would be absolutely devastating for the government's relationship with at least tens of thousands of land owners, hundreds of thousands of home owners, who would see d…

"it would be as slow as conventional rail" - citation?

Even Reason Foundation (which is as biased as it gets - it's funded by Koch brothers and ideological critic of almost any government investment) claim SF to LA times will be 3:30 to 4:40, which is faster than any train today.

Re: Hyperloop One Becomes ‘Virgin Hyperloop One’

#220

Post by jey »

daemin wrote: post #182
rando444 wrote: post #178

Earlier quoted context omitted.

It's a good thought experiment, and not without precedent.. however the main problem holding high-speed rail back in the United States is that freight trains have priority over passenger trains. Without changing this, high-speed rail in the US will never be a reality without building an entirely separate rail network.

Isn't that because the freight companies are the ones that actually built, own, and operate the tracks? If Amtrak or another passenger company owned the tracks, their trains would get priority.

No, Amtrak supposedly has priority by law: https://www.washingtonpost.com/news/powerpost/wp/2016/04/29/...
Post reply on HN