Will we ever fly supersonically over land? • Hacker News Board

Re: Will we ever fly supersonically over land?

#121

Post by iknowstuff » Sun, Jul 04, 2021, 1:38 AM UTC

fastball wrote: post #87

FreeSpeech wrote: post #74

Earlier quoted context omitted.

Wait until you hear about SpaceX.

Do you mean the methane-powered Starship, for which they plan to use the Sabatier process to get CH4 from the atmosphere?

Is the process expensive compared to just buying CH4 otherwise?

When Tesla announced superchargers, they were all about solar panels and cars powered by sunlight, but for the serious rollout they had to go with the more easily scalable, cheaper option, so very few superchargers have solar panels after all.

Re: Will we ever fly supersonically over land?

#122

Post by cortesoft » Sun, Jul 04, 2021, 1:45 AM UTC

ant6n wrote: post #67

cortesoft wrote: post #38

Earlier quoted context omitted.

I live in Southern California, with family in Kansas, Wisconsin, and New York. The closest one is 2500kms away. The longest is almost 5000kms A train would take a lot longer than a plane. Even more than just the distance, though, is the fact that there would be no practical way to have direct rail lines to every major city in the US. Trains are useful, but there is no way they could replace air travel in the US.

Well, if there was no air travel, rail lines everywhere would likely be practical... again. If trains could go 250km/h on average, that 5000km trip would take 20 hours - that's plausible for an overnight trip, leave 6pm, arrive 10am. A flight over this is distance is probably a much more stressful red eye. Sure this is quite speculative, but perhaps less so than hyperloop dreams, or supersonic aircraft that somehow h…

That seems a strange argument… yes, if we didn’t have planes, trains would be our best option… but it would be a much worse experience. 20 hours is a lot longer than the 5 it takes me to fly to New York.

If there was no air travel, I would just travel a lot less. If you want to argue that the environmental cost of air travel is too great to allow it to happen is one thing, but done act like it wouldn’t make the travel experience a lot worse.

Re: Will we ever fly supersonically over land?

#123

Post by ClumsyPilot » Sun, Jul 04, 2021, 1:46 AM UTC

katbyte wrote: post #110

flatiron wrote: post #103

Earlier quoted context omitted.

That mechanism is trying to get compensated for dead live stock and pulling straws. Thunder is a sonic boom. It’s like saying thunder killed a cow.

very loud sounds can panic/shock animals and if it's too much for them, they die.

Well, in that case, when will we start jailing bikers with loud exhausts for the deaths of old people from heart attacks?

Re: Will we ever fly supersonically over land?

#124

Post by ClumsyPilot » Sun, Jul 04, 2021, 1:52 AM UTC

the8472 wrote: post #41

agent327 wrote: post #30

Earlier quoted context omitted.

So your preferred solution is to restrict the allowed travel radius of people, a bit like with medieval serfs?

Restrictions may not be needed. Remove subsidies and price in externalties.

Most people dont realise that aircraft industry and fsrming use special fuel and pay no tax on it. While it makes sence that we sibsidiae cost of food, it is less clear why we subsidise airlines

Re: Will we ever fly supersonically over land?

#125

Post by ClumsyPilot » Sun, Jul 04, 2021, 1:55 AM UTC

beerandt wrote: post #109

jltsiren wrote: post #57

Earlier quoted context omitted.

That depends on passenger volume. Trains require massive initial investments, but the marginal cost per passenger is very low. Air travel is mostly about marginal costs, and it requires massive infrastructure at endpoints. For example, an aiport serving 50 million passengers/year is two orders of magnitude larger than a railway station with a similar passenger volume. And while the airport would be one of the 30-40 b…

Yea, which is why trains costs are so sensitive to distance- it's massive up front cost is a function of that distance. It's not the stations, it's the rails and right-of-way. The problem most people ignore is that train marginal-increases max-out at some number of trains per day, before you need an additional set of tracks. And that happens at a much lower number than most people assume, especially if you're plannin…

>"Whereas the airline equivalent is whether to schedule an additional flight. Which is easier to commit to than whether a new track is justified."

Except many world's biggest airports, like Heathrow, are operating at peak capacity and building another runway at heathrow is expensive, controvertial, involves relocating people's homes and is still a political football

Re: Will we ever fly supersonically over land?

#126

Post by ClumsyPilot » Sun, Jul 04, 2021, 1:58 AM UTC

sokoloff wrote: post #100

ant6n wrote: post #67

Earlier quoted context omitted.

Well, if there was no air travel, rail lines everywhere would likely be practical... again. If trains could go 250km/h on average, that 5000km trip would take 20 hours - that's plausible for an overnight trip, leave 6pm, arrive 10am. A flight over this is distance is probably a much more stressful red eye. Sure this is quite speculative, but perhaps less so than hyperloop dreams, or supersonic aircraft that somehow h…

6 PM to 10 AM is only 16 hours. Even with 3 time zones, you’d only be at 19 hours. 250kph straight line equivalent is unlikely given the terrain in the way (Rocky Mountains, primarily).

Tonnels, we are made massive ones through the alps in europe

https://en.m.wikipedia.org/wiki/Gotthard_Base_Tunnel

Re: Will we ever fly supersonically over land?

#127

Post by adolph » Sun, Jul 04, 2021, 2:04 AM UTC

[A] passenger version of the X-59 would be two hundred and thirty feet long, about the length of a Boeing 777, and carry around fifty people.

That’s 22ft longer than Concorde with half the px.

https://www.britishairways.com/en-gb/information/about-ba/hi...

Re: Will we ever fly supersonically over land?

#128

Post by jltsiren » Sun, Jul 04, 2021, 2:09 AM UTC

beerandt wrote: post #109

jltsiren wrote: post #57

Earlier quoted context omitted.

That depends on passenger volume. Trains require massive initial investments, but the marginal cost per passenger is very low. Air travel is mostly about marginal costs, and it requires massive infrastructure at endpoints. For example, an aiport serving 50 million passengers/year is two orders of magnitude larger than a railway station with a similar passenger volume. And while the airport would be one of the 30-40 b…

Yea, which is why trains costs are so sensitive to distance- it's massive up front cost is a function of that distance. It's not the stations, it's the rails and right-of-way. The problem most people ignore is that train marginal-increases max-out at some number of trains per day, before you need an additional set of tracks. And that happens at a much lower number than most people assume, especially if you're plannin…

Train costs are sensitive to sparsely populated regions. As long as there is a sufficiently large city every hour or so, distances don't really matter.

Multi-track railways are common near major cities. They are not that expensive, because adding another set of tracks increases the width of the corridor only marginally.

The airline equivalent of a new set of tracks is building a new runway. Because that's often impossible, landing slots at busy airports have become very valuable. For example, airlines have paid tens of millions for a daily landing slot at Heathrow.

Re: Will we ever fly supersonically over land?

#129

Post by adolph » Sun, Jul 04, 2021, 2:10 AM UTC

nostromo wrote: post #76

failwhaleshark wrote: post #61

Earlier quoted context omitted.

Flying, in-general, is inefficient unless it's a large, lifting body in ground effect.

Flying on a full or almost-full plane is more carbon efficient than driving solo. And that's not taking into account the cost of the road networks we build and maintain to allow high volumes of vehicular traffic. https://yaleclimateconnections.org/2015/09/evolving-climate-...

On a 737 jammed to the gills. Now do the numbers on an sst with 50 people.

Re: Will we ever fly supersonically over land?

#130

Post by stouset » Sun, Jul 04, 2021, 2:11 AM UTC

blunte wrote: post #101

Sound is one thing, but there are other more significant obstacles. The benefits of faster travel really show on longer distances (London to Sydney for example). But over land, there just aren’t many common routes where the several hour savings would be worth it. The big challenges relate to risk. What happens to the vehicle when a major failure happens at high speed? What about sudden pressure loss at high altitude?…

> What happens to the vehicle when a major failure happens at high speed? What about sudden pressure loss at high altitude? Or mechanical failure…

The same thing that happens in any other plane.

> … or weather which causes a diversion (how much ground do you cover just turning around?).

This is an extremely weird concern. There’s so much wrong with it I’m not even sure where to start: planes can slow down, sharp turns due to weather mid-route are not even really a thing, I’m not even sure why covering extra ground is such a bad thing anyway.