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

Re: Will we ever fly supersonically over land?

#91

Post by wpearse » Sat, Jul 03, 2021, 11:57 PM UTC

the__alchemist wrote: post #82

FridayoLeary wrote: post #72

Earlier quoted context omitted.

They did it near London once by in error. One little Typhoon can produce an unbelievably powerful sonic boom. I felt it as a loud crack/thump on my roof. Now, imagine a Concorde going supersonic...

It happens in the Lake District and Wales reasonably often. Often the pilot/crew will go out and apologize to a farmer. Sometimes livestock allegedly die, although I'm not sure what the mechanism is.

Best childhood memories are from doing walks in the Lakes and having jets zip past in the valleys below. Insanely close, too — I distinctly remember seeing the pilot’s visor and making out white text on the side of the aircraft.

Re: Will we ever fly supersonically over land?

#92

Post by pyrale » Sat, Jul 03, 2021, 11:57 PM UTC

barney54 wrote: post #75

pyrale wrote: post #56

Earlier quoted context omitted.

What a rhetoric device. Is your preferred solution to let people die in droves to a mass extinction ?

What mass extinction? From climate change? Has the Intergovernmental Panel on Climate Change said that because I’ve never seen that as a scientific claim.

We are currently going through a well-documented extinction[1]. It's not recent in human terms, but it's been accelerating recently, with industrialization.

Climate change is not the only, nor the major cause in the current extinction, but it contributes. In a way, this is unfortunate: it would be easier to have only one problem.

The relevant body for scientific information is not the IPCC, but the IPBES [2]. Like the IPCC, it releases reports summarizing the situation and its causes [3].

[1]: https://en.wikipedia.org/wiki/Holocene_extinction

[2]: https://en.wikipedia.org/wiki/Intergovernmental_Science-Poli...

[3]: https://en.wikipedia.org/wiki/Global_Assessment_Report_on_Bi...

Re: Will we ever fly supersonically over land?

#93

Post by bronco21016 » Sat, Jul 03, 2021, 11:59 PM UTC

failwhaleshark wrote: post #61

dawnerd wrote: post #37

Earlier quoted context omitted.

But are they that much worse than private jets and helicopters on a per person level?

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

I’d be interested to see a breakdown in fuel/seat-mile. I bet air travel isn’t as inefficient as the millions of people traveling alone in a car every day to work.

Re: Will we ever fly supersonically over land?

#94

Post by bluGill » Sun, Jul 04, 2021, 12:02 AM UTC

perl4ever wrote: post #80

nostromo wrote: post #76

Earlier quoted context omitted.

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-...

>that's not taking into account the cost of the road networks we build and maintain Well, why would you? Then you'd have to take into account the airports and the transportation networks to get to them...

Please do so. Airports are nothing compares to just I80 across the US. There are a lot of other roads as well that we could downgrade if more people flew.

Re: Will we ever fly supersonically over land?

#95

Post by nine_k » Sun, Jul 04, 2021, 12:03 AM UTC

avereveard wrote: post #29

t0mas88 wrote: post #12

> These studies, along with tens of thousands of claims against the Air Force for property damage—horses and turkeys had supposedly died or gone insane—led the F.A.A. to ban civil overland supersonic flight, in 1973. There was also a political part involved. The Concorde was a British-French creation, not a Boeing. Had there been a Boeing supersonic passenger plane first there would probably have been different FAA r…

not really the same, fighters are quite smaller than airliners.

I don't see why the boom energy has anything to do with the size of the aircraft producing it. It should only depend on the speed of the spike that produces the boom; typically the entire aircraft fits within the sonic boom cone produced by the nose spike when flying straight.

So I suppose an artillery shell, a jet fighter, and a Concorde should produce about the same amount of boom at the same speed of, say, 1.5 M, while flying by.

The engine sound of the aircraft, though, can add significantly to the noise in the wake of the boom cone. Those engines are not low-power or quiet.

Re: Will we ever fly supersonically over land?

#96

Post by pessimizer » Sun, Jul 04, 2021, 12:03 AM UTC

quotemstr wrote: post #70

yellow_lead wrote: post #5

They will still use an enormous amount of fuel, carry fewer passengers, and heavily pollute the environment. I'm not too excited about the prospects.

If you think that we use too much fuel, increase the price of fuel. Don't just randomly oppose specific technologies that use fuel on the grounds that you, personally, yellow_led, don't feel those technologies are necessary.

So it's alright to increase the price of fuel because yellow_led, personally, thinks too much fuel is being used, but not alright to randomly oppose specific technologies on the grounds that yellow_led, personally, thinks they use too much fuel?

I'm not following your logic. Also I don't know how you randomly oppose specific things.

Re: Will we ever fly supersonically over land?

#97

Post by sokoloff » Sun, Jul 04, 2021, 12:03 AM UTC

ClumsyPilot wrote: post #28

t0mas88 wrote: post #8

Earlier quoted context omitted.

Air travel has a big PR problem, because somehow a lot of people think it's the absolute worst for the environment. While on many routes a car is worse in terms of CO2 emission per trip than a small to mid sized airliner if there are less than 3 people in the car. Similar for your suggestion that we should take ships over the ocean, because cruise ships are much more polluting per passenger mile than modern airliners…

We coupd sctuallu fly even more efficiently, but slower, with turboprops

There’s a practical maximum amount of thrust to get from a single turboprop engine; to meet performance requirements in the event of the failure of one engine, that puts a practical upper limit on the size of two engine turboprops. Four engine turboprops would likely not be competitive with modern two engine jets, except on the shortest of legs.

Turboprops also fly lower, meaning they’re much more affected by en route weather that turbojets can often climb over. (Low and mid twenties [thousands of feet] is where much of the uncomfortable weather is. Storms that rise into the mid-30s are diverted around by most airplanes.)

Turboprops have their place, but so do jets in air carrier ops.

Re: Will we ever fly supersonically over land?

#98

Post by sokoloff » Sun, Jul 04, 2021, 12:11 AM UTC

marcosdumay wrote: post #32

harimau777 wrote: post #9

Earlier quoted context omitted.

Unless we dramatically increase vacation time or dramatically increase rail speeds, that would mean that many people would not be able to see their families and friends or travel to events.

Well, in a plane trip you have 3 lost hours before it starts and after it ends, so a normal train, running at 130km/h will be faster than a plane at 850km/h for any trip of less than ~460km. If you make it a fast train, at 350km/h, it will beat the plane on any trip up to 1700km. Most trips are short, so no, most trips can be done by train and people still spend less time on them than by plane.

I don’t lose 6 hours on a typical airline trip. Domestic, I tend to arrive around an hour before gate close time. International from the US, about 90 minutes. For a train, I’d still plan on a 30 minute safety buffer (to protect against en route delays to the station). Add another 30 minutes over the train for boarding, push, and taxi. So, I’m probably giving up an hour plus/minus however closer the train station is vs the airport.

Arriving, baggage claim rarely takes more than 30 minutes. (Delta “guarantees” 20 minutes on domestic flights.) With no checked bags, it’s the 10 minute walk through the airport and then plus/minus ground transport differences vs the train.

I can’t imagine that most people are spotting the train a 6 hour head-start, unless the live upstairs from the train station and are extremely nervous about missing their flight.

Re: Will we ever fly supersonically over land?

#99

Post by kortex » Sun, Jul 04, 2021, 12:11 AM UTC

nine_k wrote: post #95

avereveard wrote: post #29

Earlier quoted context omitted.

not really the same, fighters are quite smaller than airliners.

I don't see why the boom energy has anything to do with the size of the aircraft producing it. It should only depend on the speed of the spike that produces the boom; typically the entire aircraft fits within the sonic boom cone produced by the nose spike when flying straight. So I suppose an artillery shell, a jet fighter, and a Concorde should produce about the same amount of boom at the same speed of, say, 1.5 M,…

Why wouldn't size correlate with magnitude? A whip crack breaks the sound barrier, it doesn't shatter windows. Same with a bullet, which goes even faster.

You need both pressure level (voltage) and momentum (current) in order to stay strong over distances (shock waves diffuse over time) to break windows. Small, super fast things create large pressure differentials, big jets create more momentum.

Re: Will we ever fly supersonically over land?

#100

Post by sokoloff » Sun, Jul 04, 2021, 12:12 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…

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).