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

Re: Will we ever fly supersonically over land?

#111

Post by yurishimo » Sun, Jul 04, 2021, 12:39 AM UTC

bluGill wrote: post #94

perl4ever wrote: post #80

Earlier quoted context omitted.

>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.

I think autonomous vehicles will help here eventually too. A lot of road maintenance is due to large semi-trucks. If those vehicles are operated autonomously, they can be programmed to drive more efficiently in regards to wear on the roads. Slower braking, slower speeds (since you don’t need stops for drivers to sleep to reach your destination in the same amount of time).

We’d also see a closure of many roadside stops since there are no longer people around to use those facilities.

Re: Will we ever fly supersonically over land?

#112

Post by the__alchemist » Sun, Jul 04, 2021, 12:49 AM UTC

shiftpgdn wrote: post #108

wpearse wrote: post #91

Earlier quoted context omitted.

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.

Is the Lake District the infamous “Mach loop”?

No - the Mach Loop is in Wales. Although as the jet flys, they're not far off - so it's common to do lowfly training missions that include both. The loop has a number of aviation enthusiasts who reside there. They'll hear jet noise (or listen on the radio...), then call their friends, get out of their houses, and watch / snap pics of the planes.

Re: Will we ever fly supersonically over land?

#113

Post by Mountain_Skies » Sun, Jul 04, 2021, 12:50 AM UTC

hollerith wrote: post #55

avereveard wrote: post #29

Earlier quoted context omitted.

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

They might be smaller, but the boom is quite startling; I certainly wouldn't want to endure them regularly. I know because booms from fighters were common during my trip to West Germany in 1970. (I'm relying on what locals told my parents as to the source of the booms: I never saw a plane.) I've never heard a sonic boom in my 60 years of living in the US.

Rural Alabama had them semi-frequently in the late 70s and early 80s. Not sure where the fighters came from, perhaps Maxwell AFB had a training wing at that time. As far as I know, it never broke anything but it sure would rattle your dental work.

Re: Will we ever fly supersonically over land?

#114

Post by Mountain_Skies » Sun, Jul 04, 2021, 12:54 AM UTC

yurishimo wrote: post #111

bluGill wrote: post #94

Earlier quoted context omitted.

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.

I think autonomous vehicles will help here eventually too. A lot of road maintenance is due to large semi-trucks. If those vehicles are operated autonomously, they can be programmed to drive more efficiently in regards to wear on the roads. Slower braking, slower speeds (since you don’t need stops for drivers to sleep to reach your destination in the same amount of time). We’d also see a closure of many roadside stop…

Might also enable more frequent but smaller trucks, which also would enable more point to point movement of goods and less of a hub and spoke model.

Re: Will we ever fly supersonically over land?

#115

Post by rkagerer » Sun, Jul 04, 2021, 1:05 AM UTC

Richwine, of nasa, told me that he thinks S.S.T. could cut some flight times in half. But, he said, supersonic flight wouldn’t proportionately reduce over-all travel time until we fixed our infrastructure: How much better is flying from L.A.X. to J.F.K. in two or three hours if you spend twice that time in airports and traffic?

Re: Will we ever fly supersonically over land?

#116

Post by spodek » Sun, Jul 04, 2021, 1:10 AM UTC

harimau777 wrote: post #9

Ericson2314 wrote: post #6

Earlier quoted context omitted.

All overland passenger transport should be rail. Over the oceans I suppose we should strive for ships and dirigibles. That said, I find it hard to believe that plane travel can be eradicated for e.g. diplomacy. And frankly, if frequent contract between the powerful different countries is needed to avoid e.g. world wars, it's is worth it. In the short term, any carbon we can capture needs to go in back in ground and s…

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.

It would mean many people wouldn't choose to live flying distance from their families in the first place and they would go to local events, and people would connect more with local community.

Re: Will we ever fly supersonically over land?

#117

Post by perl4ever » Sun, Jul 04, 2021, 1:13 AM UTC

bluGill wrote: post #94

perl4ever wrote: post #80

Earlier quoted context omitted.

>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.

I would need more information to flesh out how you think my default assumptions (that indirect costs are approximately proportional to direct costs) should be revised.

Facts and logic are optional, but at least a quantitative assertion that's falsifiable would be a start.

Re: Will we ever fly supersonically over land?

#118

Post by paul_f » Sun, Jul 04, 2021, 1:21 AM UTC

Mountain_Skies wrote: post #113

hollerith wrote: post #55

Earlier quoted context omitted.

They might be smaller, but the boom is quite startling; I certainly wouldn't want to endure them regularly. I know because booms from fighters were common during my trip to West Germany in 1970. (I'm relying on what locals told my parents as to the source of the booms: I never saw a plane.) I've never heard a sonic boom in my 60 years of living in the US.

Rural Alabama had them semi-frequently in the late 70s and early 80s. Not sure where the fighters came from, perhaps Maxwell AFB had a training wing at that time. As far as I know, it never broke anything but it sure would rattle your dental work.

You are correct. I clearly remember hearing sonic booms in Montgomery, AL in the early 70s.

Re: Will we ever fly supersonically over land?

#119

Post by ClumsyPilot » Sun, Jul 04, 2021, 1:29 AM UTC

beerandt wrote: post #102

crazygringo wrote: post #40

Earlier quoted context omitted.

Do you have a citation for that? Quick Googling doesn't reveal any obvious authoritative answers (but a ton of guessing and unsubstantiated claims). The most authoritative/unbiased source seems to be this Wikipedia article: https://en.wikipedia.org/wiki/Energy_efficiency_in_transport But the head-to-head comparisons are mostly gaps when it comes to trains, and the sections on trains and planes are in completely diffe…

It was covered in a sustainable engineering class I took. There's not much generic into about it because every rail route proposal is different, even between the same destinations. Depends a lot on geography and what's already there. You basically need to do a full Life Cycle Analysis (LCA) for each route. Sometimes they're included in the EIS for a proposed project. That's prob the best place to start. But there's a…

China has more high-speed than the rest of the world combined, with even remote parts of China hooked up to the rail network.

And when you compare energy, you have to take into account that Rail is already electric, powered directly by grid without batteries or any other efficiency loss in between.

Airplanes use fuel that takes a lot of energy to refine and deliver, and will at best use hydrogen in 15 years which is 40% efficient to produce, plus losses in compression, delivery, engine, etc.

Re: Will we ever fly supersonically over land?

#120

Post by jesseb » Sun, Jul 04, 2021, 1:32 AM UTC

FreeSpeech wrote: post #74

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.

Wait until you hear about SpaceX.

A Falcon 9 launch produces comparable carbon emissions to a trans-Atlantic 777 flight. There are considerably more trans-Atlantic 777 flights than there are Falcon 9 launches.