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Will we ever fly supersonically over land?

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Re: Will we ever fly supersonically over land?

#201

Post by LargoLasskhyfv »

blunte wrote: post #173
stouset wrote: post #130

Earlier quoted context omitted.

> 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 turn…

> The same thing that happens in any other plane. https://en.wikipedia.org/wiki/List_of_aircraft_structural_fa... The faster you are traveling (which really matters as a factor of the drag you are experiencing), the more serious any event is which changes the shape of your vehicle. Even non structural failures, such as an engine cowling coming off mid-flight can strike other parts of the aircraft, resulting in damage…

They go higher than normal passenger jets. Thus they could glide longer, because they'd start from an altitude of anywhere between 13 to 16 kilometers up, maybe even 20km. There is almost no weather to speak of there, and if so it wouldn't require a sharp turn, because anything reaching up there would be visible from far away. (like a thunderstorm)

That's the whole point of so called high-altitude/high-atmospheric platforms as an alternative to low orbiting satellites. (Think stationary blimp with many antennae/transponder on its belly for internet, or something)

What are you smoking!?

Re: Will we ever fly supersonically over land?

#202

Post by LargoLasskhyfv »

ClumsyPilot wrote: post #21
Ericson2314 wrote: post #15

Earlier quoted context omitted.

Absolutely not. 300 kph HSR rail exists in developed countries. (2680 miles) / (300 kilometers per hour) = 14.3768064 hours That's coast to coast in ~ 1/2 day. Ships and blimps represent a much larger decrease in travel time over airplanes than rail. They perhaps pose a to be solved, but rail doesn't.

And you can go ecen faster >"TGV called V150 holds the record for the highest speed on any national rail system - it hit a whopping 357.2 mph "

Probably not during normal operations. IIRC they put more mechanical tension on the overhead catenary, also more voltage on it, and used slightly larger wheels. That was more of testing the absolute limits of what you can do with that sort of system, materials- and mechanics-wise.

Re: Will we ever fly supersonically over land?

#203

Post by bluGill »

nradov wrote: post #145
yurishimo wrote: post #111

Earlier quoted context omitted.

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…

Road wear is caused by weight. Driving and braking slower won't make a significant difference.

An autonomous vehicle can keep the tires to the same track within 3cm. So there is potential to build pavement just where wheels go and corners.

I don't believe it, but it is possible.

Re: Will we ever fly supersonically over land?

#204

Post by over_bridge »

ClumsyPilot wrote: post #123
katbyte wrote: post #110

Earlier quoted context omitted.

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?

I dream of a day when light and noise pollution are taken seriously. Its exhausting walking beside a busy road with the roar of traffic. You see the birds don't even bother to try and sing anymore. They are just silent and isolated until they get further away. Visual pollution from advertising would be great to curb as well.

Re: Will we ever fly supersonically over land?

#205

Post by ant6n »

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).

China built tens of thousands of km of high speed rail for 350km/h. Largely using prefab elevated tracks, with occasional tunnels.

Again it’s difficult, but possible if a replacement for air travel was considered a necessity.

Re: Will we ever fly supersonically over land?

#206

Post by stouset »

blunte wrote: post #173
stouset wrote: post #130

Earlier quoted context omitted.

> 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 turn…

> The same thing that happens in any other plane. https://en.wikipedia.org/wiki/List_of_aircraft_structural_fa... The faster you are traveling (which really matters as a factor of the drag you are experiencing), the more serious any event is which changes the shape of your vehicle. Even non structural failures, such as an engine cowling coming off mid-flight can strike other parts of the aircraft, resulting in damage…

Also, you might want to actually read the Wikipedia article you linked.

There have been ten total cases of structural failure in the past twenty years of aviation. Two of those involved spacecraft (Space Shuttle Columbia and VSS Enterprise). One of them was a terrorist bombing (Metrojet 9268). One was a fighter jet (F-15).

So six left. In all of those six, there were essentially 100% casualties. So how exactly would a supersonic jet be "worse"?

Re: Will we ever fly supersonically over land?

#207

Post by inglor_cz »

LargoLasskhyfv wrote: post #189
inglor_cz wrote: post #158

Earlier quoted context omitted.

"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." About a quarter of all railway passengers in Czechia take the suburban trains around Prague. We sorely need extra sets of tracks from all directions, because the current tracks are overloaded. Especially the faster trains from other regions do not…

Do it as subways in a way like the new lines in Barcelona did. edit: By that I mean something like illustrated here https://ca.wikipedia.org/wiki/L%C3%ADnia_9_del_metro_de_Barc... Make them 15 to 16 meters in diameter to be usable by any train, or use 2 of them side by side. Problem mostly solved.

It can be done, but geology under Prague is terrible. A lot of broken layers with lots of sediments and water.

Our subway system was rather expensive to build and maintain, doing this with trains would probably be too expensive even for a fairly rich city like Prague.

There are some rudimentary plans for railway tunnels under the very center of the city, but the expected cost is eye-watering.

Re: Will we ever fly supersonically over land?

#209

Post by tdeck »

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.

The trouble is that we've all organized our lives around fast air travel and it's hard to unring that bell. I might not interviewed at a tech company in SF and then moved out from Pennsylvania if I knew that every journey back to see my parents would take 5 days each way by train. Many of us have close relationships scattered across long distances, which was less true before the advent of affordable air travel.

Re: Will we ever fly supersonically over land?

#210

Post by LargoLasskhyfv »

inglor_cz wrote: post #207
LargoLasskhyfv wrote: post #189

Earlier quoted context omitted.

Do it as subways in a way like the new lines in Barcelona did. edit: By that I mean something like illustrated here https://ca.wikipedia.org/wiki/L%C3%ADnia_9_del_metro_de_Barc... Make them 15 to 16 meters in diameter to be usable by any train, or use 2 of them side by side. Problem mostly solved.

It can be done, but geology under Prague is terrible. A lot of broken layers with lots of sediments and water. Our subway system was rather expensive to build and maintain, doing this with trains would probably be too expensive even for a fairly rich city like Prague. There are some rudimentary plans for railway tunnels under the very center of the city, but the expected cost is eye-watering.

Tap into the limitless cornucopia of the EU. For protecting the historic scenery, cultural heritage, being good for the environment, enabling shorter travel times, supporting tourism, intercultural exchange...

We're in a phase of low interest rates, resulting in easy money politics. Burn some billions before others do ;->

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