[AlphaCharlie]

The faster the plane goes, the more fuel it consumes due to the drag increase by the square of the speed. In a world where fossil fuel is needed to fly airplanes and where oil is causing a destruction of the world we inhabit, it's dangerous to suggest we should make the flying industry polluting more than they already are.

If anything we should look at the trade-off benefits of flying with the least amount of fuel consumption per passenger and miles flown. Flying faster than mach-1 to save time will be reserved to a small elite. How does it benefit the masses?

[oceanplexian]

I’m a pilot and this is… a vast oversimplification. Jet aircraft are significantly more efficient at higher speeds and at higher altitudes precisely because there’s less drag up there and the engines can operate more efficiently. They are wildly inefficient when low and slow.

A lot of the assumptions people make about efficiency don’t hold water in aerospace. There are no laws of physics preventing supersonic aircraft from being efficient provided they can fly high enough and we figure out how to build better engines.

[sandworm101]

While true at cruise speeds/altitudes, any supersonic transport still has to climb up to those altitudes. On any american flight (not to alaska/hawaii) i doubt the greater efficiencies at 60+ thousand feet would be worth the fuel to get there with a supersonic wing. These would only be 2 or 3-hour flights at most anyway.

If we really want time savings, fix the entire airport experience. Thats where time can be most saved. When travelling domestic I ussually end up spending far more time waiting for flights/bags/security than actually flying.

[rkagerer]

If you're old enough, there was a time before the airport experience was so broken when you could show up 15-20 mins before your flight.

[MiscIdeaMaker99]

That would be me!

I remember the times before September 11, 2001, when I could show up at the airport about 30 minutes before my flight, get through security (which was locally operated -- no TSA), get my boarding pass at the gate, and board. It was great!

People could also meet you at the gate when you arrived, instead of outside the security area. There would always be peoples' families and loved ones there waiting for them.

[dguest]

Geneva, CH, recommends that you arrive less than 2 hours before your flight departs.

If you are flying within Europe, without checking a bag, and have the QR code from your boarding pass, it always takes less than 30 minutes to get to the gate. Allowing an hour is more than safe.

[ruszki]

It’s good to assume that it heavily depends on airport, and time. I’ve been many times in the past years when just security took me more than 30 minutes. There are airports where it’s always less than 10 minutes (especially if you know some tricks), and there are airports where it depends on time. One hour is a good rule of thumb in Europe nowadays if you don’t have checked baggage. It would have been a stretch a few times, but I would have never missed a flight if I had been there only 1 hour before departure.

[simon1573]

Last summer was crazy for popular airports in Europe, with queues lasting for multiple hours just to get _to_ security. It was said that it was due to staff shortages due to layoffs during the pandemic though.

[secfirstmd]

I have flown out of there recently and this would have been terrible advice. Really bad queues for bag drop and security.

[glenngillen]

Come to Australia. These times still exist.

[euroderf]

At the right time on a good day, you can hop off the bus at Helsinki airport and be thru self-checkin AND security in about seven minutes flat.

[JohnFen]

Me too.

The airport experience is why, even though I enjoy actually flying, I avoid doing it to the greatest degree I can. Everything that happens from the time I arrive at the airport to the time the airplane leaves the runway is awful.

[noduerme]

TTP/Global Entry sort of fixes this. What really fixes it is flying private. Unfortunately, that's doesn't do much to help the carbon problem.

The real difference now is that flying is too affordable. It used to be, only the rich could fly.

What we need to do is make air travel much, much more expensive, out of the reach of most people except on special occasions, and we can go back to having (1) less unnecessary carbon emissions from people flying to Disneyland or whatever shitty resort they spend their vacations at, and (2) very short waits at the airport for people who need to get somewhere in a hurry and can afford it.

Environmental and efficiency problem solved.

[quags]

Wow that would be very heavy handed and really assumes that the rich traveling are some how more meaningful for whatever destinations they are going to - maybe flying to some shitty meeting in Sweden that could be done over video conference. By this logic inflation happening now will fix the problems in the world bringing all prices up and forcing most people to become vegans because meat becomes too expensive and will also be for the rich only. Then cars can be for the rich too and in the end we can let the poor sit with out technology at all leaving only the rich one percent having all the carbon emissions. Finally the environmental crises is solved.

[Ntrails]

> really assumes that the rich traveling are some how more meaningful

No, it assumes you care about reducing air travel more than equality of access to it

> forcing most people to become vegans because meat becomes too expensive

Sounds...effective? It isn't what is happening, but taxing the hell out of meat would be a great lever to pull if you want to drive consumption away from it.

Outside of cost the only possible lever is rationing. Good luck with that one.

[fallingmeat]

“… TTP/Global Entry sort of fixes this…”

wish that were true, but the variance of wait time, even with tsa precheck, etc defeats the purpose. needs to be reliably consistent (and short) for me to take advantage of a 30min show time.

[wkat4242]

Those problems solved but a lot of other problems created. This genie can't go back into the bottle that easily. People live in other countries or states now and want to see their families too.

[sandworm101]

I am old enough, but arriving 20min before a flight was never really a thing. You could in theory arrive that way, but you were running a risk. Any delay in security, a delay in the bus system, or just bad luck with an irrate customs person could always delay you a few minutes too long. And if you werent even checked in 20min before your flight you had a very good chance of being bumped off the flight for someone on standby. There was also zero chance of any checked bags making it onto your flight unless you were checking in at least an hour before travel.

[londons_explore]

An plane could be like a bus...

Show up, hop on, tap your credit card to pay, and the plane takes off while you're still wandering down the aisle looking for a seat.

[fallingmeat]

I like where your head is at! make that the vision.

/fire suit on

[patrickmcnamara]

The last time I flew through Dublin airport I got from my taxi to my gate in 16 minutes including checking in a bag. I had arrived 3 hours early nonetheless due to the "chaotic" queue times I had read about.

[m-p-3]

This is one reason why I prefer to take the train for work whenever possible, even it takes longer and isn't that much cheaper, the onboarding experience is awfully simple and relatively stress-free.

[Fatnino]

You are obviously on the east coast.

From the bay area, there is nowhere you might want to go that a train would make less stressful.

Want to go to LA? That's 1 hour in the air for around 100 bucks. Or it's a 10 hour ordeal involving transfers between coach bus and train in more than one location. All for the low price of 60 dollars.

Want to go to New York? That's 6 hours by air or 80+ hours by rail. Where realistically you are going to book a roomette ($$$) and not just sit in coach for 3 days straight.

[gkedzierski]

Still a thing at LCY

[ccakes]

> On any american flight (not to alaska/hawaii) i doubt the greater efficiencies at 60+ thousand feet would be worth the fuel to get there with a supersonic wing. These would only be 2 or 3-hour flights at most anyway.

Hi! There are many of us who exist outside of the US and would be open to planes flying faster because the world is super big. Thanks for listening

[dragonwriter]

> Hi! There are many of us who exist outside of the US and would be open to planes flying faster because the world is super big.

Sure, but that isn’t particularly affected by restrictions on supersonic flight over the US.

[ballooney]

Yes it is.

(London-LA semi-frequent flyer).

[jessaustin]

Los Angeles is not "outside of the US". Besides, less than 20% of that trip is in USA airspace. Slow down when you hit North Dakota...

https://www.greatcirclemapper.net/en/great-circle-mapper.htm...

[robopsychology]

Only a recreational pilot but I agree, when we calculate fuel usage (because people want you to pay your share this is a serious topic) there’s so many more ‘real’ variables

[Gravityloss]

Yes, from basic principles, energy is force times distance. This force on an airplane is drag. Since on an airplane, both the drag and lift are proportional to the square of velocity, if (thought experiment) you assume a fixed lift to drag ratio, speed cancels out. It doesn't affect energy usage.

Basically a faster airplane can have smaller wings which produce less lift and less drag. If we in spherical cow tradition ignore body drag, you can halve wing size, increase speed by 44% and have the same drag. You need more power but for a shorter duration, for the same energy usage per trip.

[albrewer]

You're ignoring the efficiency of the jet engine itself. You have to basically pick an altitude, temperature, and speed at which the engine is most efficient. Modern airliners are most efficient at a certain speed and altitude because they're designed to stay under the supersonic regime.

It's been a long time since I've touched compressible fluid mechanics or turbomachinery design, but if I recall correctly the theoretical "sweet spot" for overall aircraft efficiency is something like Mach 1.3. I'd have to dig though my textbooks to remind myself why, but the number stuck with me.

[Gravityloss]

Definitely! I remember seeing an old picture of a physical three dimensional plot about theoretical airliner efficiency. X axis was speed, Y axis was something else and Z axis was efficiency. I think it was made of wooden shapes. There were two local maxima there, one subsonic and one supersonic. Probably it was related to the US SST project.

Can't find the picture anymore...

[dredmorbius]

Most commercial aircraft take off and land well below their cruise speed. My understanding is that this limitation applies to supersonic aircraft as well. Applied power is typically restricted due to noise control requirements near airports.

That wing lift/drag relationship may be less fungible than you're supposing in order to address lower-speed flight segments.

[Gravityloss]

Yes, it was just a thought experiment from first principles to get a feel for the problem.

In reality, planes fly higher where the air is less dense, and faster to keep the lift and drag equal.

In a car, lift is not needed. Higher speed doesn't have compensating effects. Higher speed more clearly causes more fuel burn for the distance.

[dredmorbius]

Fair enough.

If anything, automobiles frequently utilise negative lift, as with a Formula 1 or Indy Car's inverted wing which generates increased downforces. On street cars you'll find spoilers and similar factors.

Aircraft can fly low and fast, though that's typically associated with combat aircraft evading radar or air-defence systems. Such missions are known as fuel-burners precisely because of the greatly increased drag.

[sillysaurusx]

I don’t think people will believe you even though you’re right. Pure math has a strange way of swaying one’s opinions; ML in particular suffers from this.

But thank you for trying to point out that engineering efficiencies matter a great deal. Hopefully the message will get through.

[witheld]

I thought you were saying that Marxism-Leninism suffers from naivety of pure math and I was really twisting my brain working that one out

[sillysaurusx]

Economic theory isn’t free from this phenomenon either. :) Though I wonder if it’s possible to model the probability of a communist revolution.

[ithkuil]

Ah finally I understand why everybody is so worked up about Anarchist Ideology lately

[djaychela]

>Jet aircraft are significantly more efficient at higher speeds and at higher altitudes precisely because there’s less drag up there and the engines can operate more efficiently.

This is true, but isn't the flip side of this that the high altitude emissions are much more damaging?

[ramraj07]

Please unsimplify this then? Can you give a scenario where flying faster would be more economical fuel-wise?

[mdmglr]

This should enlighten you: https://aviation.stackexchange.com/questions/1609/why-do-jet...

[selectodude]

It’s not a linear relationship but unless you’re flying in space, you’re going to deal with the fuel vs speed trade off.

[TylerE]

If you fly too slow the wing will start to stall, so you have to pull the nose up to raise the angle of attack…. Which vastly increases drag.

[Timshel]

It's an oversimplification but as far I understand it's not wrong at least with past/current projects.

Efficiency for a given aircraft is nice but it's not the point. I believe Concord was most efficient at cruising speed (~Mach 2) but it does not change the fact that it burned like 4x more per seat/km than a b737 (Cf: https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft). Of course Concorde was only first class but that's part of the point of the parent.

As for boom, some guesstimate are around at least 4x too (https://theicct.org/new-supersonic-transport-aircraft-fuel-b...). No idea how biased this is but I believe it's quite telling that there is only mention of SAF on https://boomsupersonic.com/sustainability. At best in some 2017 article they compare themself to a lay-flat bed in subsonic business class, but since they only manage to secure an engine maker last year it was firmly in the guesstimate too.

[FuriouslyAdrift]

New York to London round trip ticket price was $14,522 in 2023 dollars...

[russdill]

Ok, then limit airspeed and not true airspeed. Done.

[verandaguy]

I strongly agree with your point, but I think some extra context is warranted.

As it stands, the economics of air travel force carriers to optimise for reducing fuel consumption, since that's (by far) the biggest fraction of a commercial aircraft's operating cost.

If supersonic transport makes a comeback, it'll be because the economics will make sense, which (in my mind) will be either because of:

- Somehow reduced fuel consumption, potentially through engines that leverage the effects of the supersonic flight regime for increased fuel efficiency (e.g. ramjets, through that likely wouldn't be possible in low-supersonic flight)

-> As another commenter in this thread mentioned, drag decreases with lower atmospheric pressure at higher altitudes, so there are fuel efficiency gains to be made just by flying higher, within the engines' design constraints.

- It'll fill the niche of richer-than-god people who use jets to skip highway traffic.

There's likely more cases than just these, but these are just the greatest hits as far as I can tell; and I say all of that as someone who's not involved in the aviation industry.

For the record, I don't support this second niche existing, but it does, and it can be an economic driver.

[bobthepanda]

> As it stands, the economics of air travel force carriers to optimise for reducing fuel consumption, since that's (by far) the biggest fraction of a commercial aircraft's operating cost.

Not only this, but in general jet speeds have decreased due to airspace congestion. There is a lot of schedule padding due to delays at hubs like JFK, LAX, LHR, etc.

[seanmcdirmid]

Flights to and from Beijing between the USA have (or had before the pandemic) at least a one hour pad due to PLA airspace restrictions popping up randomly combined with airport congestion. It often meant arriving in Seattle early before customs and immigration opened.

[CyanBird]

The second niche as a rule of thumb pollutes-more-than-God already(0)

I am skeptical that lifting barriers to them polluting more would land any type of net benefit given that ultra-luxury products such as said jets don't tend to land outsized downstream advancements than let's say, funding basic sciences such as what Boeing or Airbus are already doing

(0) https://www.oxfam.org/en/press-releases/billionaire-emits-mi...

If it could be proved that things like faster private jets or faster planes could benefit in a sizeable and proportionate way to the general public, then yeah I would be in favor of this too, but as it stands I don't find the available info compelling, I'd rather them to pay more taxes

[verandaguy]

You're preaching to the choir; human progress isn't proportional to the number of billionaires with fleets of Gulfstreams (or rather, if it is, there's almost certainly no causation there).

[aaomidi]

I’m constantly in pain about how much human ingenuity takes the back seat just to keep the wheels turning in lives. If we actually tried to meet most of the requirements for people, creative thinking would flourish.

[seventytwo]

100%.

I like to bring up the question of how many startups and how much innovation is stifled because people stay with their jobs because of the healthcare.

[jandrewrogers]

Isn’t Europe evidence of the answer to this question?

[oceanplexian]

I’m not a billionaire apologist, but billionaires get a lot of flak for using private aircraft where it makes a lot of sense.

Zoom is not a valid substitute when you’re trying to make high stakes decisions that involve millions - billions of dollars and complex relationships in multiple time zones. Saying that human progress depends on it is a bit dramatic but these folks allocate large amounts of capital and have an outsized impact on the economy.

[CyanBird]

Sure, but the private jet usage is not exclusively to said high level meetings.... If it were, then the Oxfam piece above would be singing a quite different tune

[grumple]

Crew and maintenance are both higher costs for most airlines, according to this and other sources I've found: https://www.icao.int/mid/documents/2017/aviation%20data%20an...

Let's say that you can now make twice as many flights in a day. You can now do twice as many flights with the same crew and aircraft (same maintenance costs). Your fuel costs increase, but your other costs remain fixed, so despite the increase in fuel costs, you still end up making more profit. You might be able to charge more for the faster flights as well, and there may be beneficial second-order effects.

[htag]

> It'll fill the niche of richer-than-god people who use jets to skip highway traffic.

To skip highway traffic a richer-than-god person would use a helicopter. Private jets are used for further distances.

[javiramos]

https://www.theguardian.com/environment/2022/jul/21/kylie-je...

[ClumsyPilot]

"She was attacked by twitter users"

Nice language, was she stabbed? Has she lost money, job?

Why conflate well-deserved criticism with violence?

[h0h0h0h0111]

attacked is a widely used synonym for criticised

[htag]

> to assail with unfriendly or bitter words

https://www.merriam-webster.com/dictionary/attacked

[oliwarner]

Given the ecological cost, the economic balance has to be thumbed; taxed to the hilt to fund restorative programmes.

Being absurdly rich shouldn't give you license to destroy the planet.

[golemotron]

I hate to break it to you but the planet is very resilient. It was here long before humanity and it will be here and habitable for life long after we've disappeared or evolved into something else.

[seanmcdirmid]

When we say “destroy the planet”, it usually means making it inhabitable for human (as we are) life, Mother Nature would recover in the long term, but in the long term we would be dead.

[golemotron]

Global population is set to decrease dramatically as industrialization's demographic wave passes. Pollution will decrease with it. It's a plot change many haven't noticed yet.

[seanmcdirmid]

Climate change skeptics think humans have little to do with climate change and so we are all doomed anyways (conservation won’t help, so YOLO). Definitely Mother Nature will correct it one way or another, and humans could be totally obsolete in a few centuries anyways. I’m not sure if I’m comfortable using this as justification to drive a canyonero.

[runarberg]

We are already almost at +1.5° C, we are looking at +4° C at the end of this century with the current trends. The Global population will still be around 11 billion (3 billion more than today) in 2100 (if we are not all dead at that point from wars and famines which is inevitable after 4° warming).

[geysersam]

How are people still not understanding that acting to prevent climate change is a cost saving measure?

It's not about saving humans from extinction.

It's just the smart thing to do unless we want to spend massive amounts of resources in the future to adapt to the consequences of a warming climate.

[oliwarner]

This is a pretty odd outlook.

As trajectories go, currently habitable places will become uninhabitable within the lifetime of people you know. And that process isn't nice. Becoming uninhabitable means a series of natural disasters (and clean water pressures) that force people to migrate. Mass migration means global turmoil as people scramble to get safe. And many will die along the way. That's already started.

The planet will physically be here but its habitability matters too. I don't really care about what comes after humans, as long as it doesn't come now and kill me and mine.

If your only argument is "life, uhh, finds a way", that's great. Thank you for your contribution. Now find us a way to relocate a billion people in the next three decades.

[seattle_spring]

You might be ok with breathing air that tastes like dirty anus and gives you cancer in exchange for some added conveniences, but me and I'd hazard to guess most other people would rather make some concessions so our planet is as healthy as possible.

[ClumsyPilot]

Yeah, if we stanrt a nuclear holocaust, the planet will still be here, but all its inhabitants will be dead.

The best combination of being technically correct of missing the point.

[TechBro8615]

Actually, a nuclear holocaust would most likely not lead to all humans losing their lives. Many, if not most, would survive. Even some in the cities and their immediately surrounding areas would survive. Unless you tell everyone to go outside in the middle of their nearest city right before the bomb drops, you're going to be stuck with humans even after the dust settles.

[ClumsyPilot]

the overall point was that the planet has survived things that humans cannot survive. There were 5 or 6 mass extinctions.

When peopme talk about the planet being destroyed, they usually mean for human life.

[TechBro8615]

Stop it. We must seize the wealth of all billionaires before the water rises to the second rung of the ladder on Barack Obama's dock in Martha's Vineyard.

[drewcoo]

> If supersonic transport makes a comeback, it'll be because the economics will make sense

And not because it kills the planet less.

[cue sad trombone]

[Nextgrid]

You can offset environmental impact by excise-style taxes on the polluting activity that are used to subsidize environmentally-friendly processes elsewhere that would've otherwise used fossil fuels due to cost.

It's not perfect (as fossil fuels are still being burned) but it's better than nothing and a much more realistic solution than some extremist ideas such as stopping using fossil fuels overnight and effectively shutting down the economy as a result.

[kelseyfrog]

You could, but you could also maintain the status quo. Not everything needs a market based solution.

[Dylan16807]

You can tax enough to remove 150% of the pollution. I'd call that much better than the status quo. And that's before we talk about the usefulness of funneling rich people money into technology research.

[bobthepanda]

IIRC, with aviation fuel it's kind of complicated due to international treaties on taxation of fuel.

[wkat4242]

Yeah and those are necessary to avoid airlines filling all the way up at the cheapest location and thus wasting more energy carrying unneeded fuel around

[AlphaCharlie]

That's a very eloquent way to put it, I agree to it all :)

[r2b2]

Why mix regulation of two effects (sound and emissions)?

It's smarter to write regulation for each uniquely and directly.

Eg.

- Sound from air traffic shall meet <sound regulations> and when violated will incur automatic fees of <formula> amount.

- Air traffic emissions are required to meet <emission regulations> and will be taxed at <formula> amount (which should be used to offset pollution).

[msm_]

I agree with you in principle, but it's probably easier to enforce speed limits than sound and emissions (because both are hard to measure while in air, in contrast to speed).

[capableweb]

Sound would be measured at the ground, I presume, as no one is really bothered by loud things up in the sky, but by the ground.

For emission, require airlines/airplanes to have a emission-sensor installed that automatically measure the emission. As a part of take off, make it mandatory to check it's working and as a part of landing, make sure it sent there data to where it has to go.

[cat_plus_plus]

You know you can just tax fuel according to amount of carbon right?

[c0balt]

“If the penalty for a crime is a fine, then that law only exists for the lower class”

[cdogl]

Be careful witn that reductive reasoning. Fines are an entirely reasonable mechanism to regulate an industry that is highly competitive with tight margins.

[reillyse]

You are contradicting the commenter but I don't think you understand fully what they mean. I took their comment to mean that rich people won't care about a fine and will happily continue polluting. Your statement about "tight margins" is exactly what they are referring to. Only people who care about "tight margins" i.e. poor people, i.e the majority of us, will be effected while rich people who do a disproportionate amount of damage will be able to shrug off the law.

[ericd]

I'd keep in mind that when people talk about the rich doing a disproportionate amount of the damage, if you're American, you're almost certainly who they're talking about. It's the normal American lifestyle that's doing the bulk of the damage, not specifically the richest of the US. The car-centered suburban lifestyle of much of the middle class is an environmental disaster. But sure, bigger houses made with more material and more flights by richer Americans aren't helping.

[Retric]

The middle class in America have a small impact on climate change just like they have a small impact on most things. If you want to understand what’s going on look into who was running disinformation campaigns and actively sabotaging efforts to add carbon taxes etc.

People love to blame SUV’s because they are in peoples faces, but replace every American SUV with an EV and the impact on the climate is negligible. Things would get just as bad a few weeks later, and that’s about it. People blame the rich and powerful because when you blame the people running things when things are fucked up.

Consider, the option for electrified roads instead of burning hydrocarbons existed 20 years ago. We could have reduced gasoline use by around 90% by now without any great breakthroughs but such choices aren’t up to individual consumers.

[imgabe]

Poor people are not flying airplanes. They are operated by large corporations and wealthy individuals. This criticism of fines is not relevant here.

It’s not like “oh the average Joe making 50k a year won’t be able to fly his supersonic jet because of the fines but rich people will”

[super256]

> Only people who care about "tight margins" i.e. poor people

No. Rich people, who fly business and first class still fly with the same airlines as poor people. The margins of the entire industry are thin.

[aqme28]

There’s no “lower class” when we’re talking about the people and corporations who own jet aircraft.

[dan-robertson]

This seems like a pretty bad reason to want speed limits, because the thing you actually want to limit is fuel inefficiency. I think rules should normally try to achieve their goals through first-order effects rather than second order effects.

I don’t think wanting fuel efficiency is incompatible with getting rid of the speed limit rule.

[idiotsecant]

Sometimes behaviour is legislated through second order behaviours because legislating first order behaviour is politically sensitive, or sometimes because even though the primary behaviour is already legislated the second order behaviour is as well. Not saying it's right, but it's exceedingly common.

I'd make an example but these are exactly the sort of things that launch off topic 10 page discussions with very low information content.

[dan-robertson]

Sure, there are exceptions. When I wrote ‘normally’ to cover them, I was more thinking of things where it is hard to set good metrics for the thing one wants controlled, or cases where avoiding the spirit of the rule would be too likely.

Nevertheless, I think those are exceptions. I think first order effects tend to matter more than second order effects (that’s why they’re called first order) and not doing good first-order things because of potentially bad second-order things is often wrong.

[slowmovintarget]

And sometimes the legislation is the way it is because the legislature works from an understanding that is easy to popularize... and wrong.

[sokoloff]

I agree with you and, in this case, taxing Jet-A seems like an incredibly straightforward way to accomplish this.

[buck4roo]

That sound you hear from aircraft overhead -- yeah, that's wasted energy.

Do you want waste? Because that's how you get waste!

[mgbmtl]

I would be a bit skeptical, considering how many car makers tried to trick the measurement of emissions. Create a metric, people will game it.

[dan-robertson]

Cars are regulated pretty differently from air travel though? And airlines are already quite incentivised to use less fuel as it’s a huge cost. I think it’s just a case of different things being different.

[itake]

Even perfect fuel efficiency, higher speeds will require more energy than lower speeds.

More energy will cost more fossil fuels.

[dan-robertson]

Doesn’t nearly-supersonic flight require more fuel than supersonic flight, at least in some cases? That seems to contradict fuel efficiency being a decreasing function of speed.

[snapplebobapple]

This is a terrible argument because it presumes there are no uses of faster travel that are beneficial. The proper argument is for a carbon tax that captures the externalities caused by emitting carbon and then to let individuals decide if they want to pay that or not for whatever activity they are partaking in.

Whether it benefits the masses or the elite is irrelevant, what is relevant is that the use is worth more than the correctly priced cost of carbon

[thfuran]

>Whether it benefits the masses or the elite is irrelevant

Why is that irrelevant? Must we permit everything that might be of benefit to someone, even if it comes at the expense of everyone else?

[snapplebobapple]

Because the problem with carbon is that the cost of emitting it is not reflected in the market price of the things emitting it. This is called an externality in economics. You fix the externality by taxing the carbon emission at a level that covers the externality. After that you let the much more efficient market sort out what emits and what doesn't because it does a far better job than than any grouping of hacker news commenters expressing what ever combination of the seven deadly sins you think makes them hate the most productive people in society. Markets work and envious, wrathful authoritarians don't. You just end up with another episode of great moments in unintended consequences going down that road.

[thfuran]

>Markets work and envious, wrathful authoritarians don't.

So EPA, FDA, etc regulations should be replaced with fees for poisoning everyone rather than outright bans, because to desire freedom from such concerns is to be a jealous tyrant?

[snapplebobapple]

The short answer is: some should be replaced, some should be cancelled outright for being stupid, and some are great ideas that should continue. Those two institutions are massive and encompass such a large variety of things that they have things in all categories (should be taxed instead, should be cancelled, and should stay banned).

The technically correct answer but practically silly answer is: yes because the correct charge for the externality of poisoning everyone would be asymptotic and unaffordable by anyone so it would amount to a ban.

Also the concern is not about being a jealous tyrant, the fact of the matter is markets almost always work better than dictating what to do, especially in the long term due to reacting to new information more effectively and changing course more effectively than an authoritarian regime.

[michaelmrose]

When something is banned any action including planning to do it at all are criminal conspiracies and its hard to change this. When something is taxed its an easier ask to reduce the cost, to play games with finances and parent child company relationships, or just go bankrupt and not pay. The penalties, costs, resolutions for not paying your bills are completely different by design compared to the tools to respond to active plans to commit crimes thus using fees to control things nobody should ever do is ill conceived at best.

Insofar as market based solutions I don't know why you imagine they should work. People are in general hideously stupid, immoral, incapable, greedy, and useless. The only way to make them behave with any modicum of sanity and decency is for someone educated in the topic of interest without a dog in the fight to stipulate based on objective standards the kind of things one must and must not due in order not to fuck their fellow man.

The fact that this at present remains less than ideal doesn't mean we ought to trust the same immoral pieces of garbage with less controls on the notion that they will do a better job that way rather than trivially corrupt the over-complicated process. By and large we know very well in most instances exactly what one should and shouldn't do we don't need a market based solution to figure it out we need a less bought and paid for government to actually implement what we already know.

[avereveard]

How are fines from fda and epa different than fees?

[nitwit005]

We ended up with food safety laws because people did things like knowingly sell unsafe adulterated milk, causing thousands of infants to die (https://en.wikipedia.org/wiki/Swill_milk_scandal). If you do that these days, you will simply go to jail.

Or get executed, as happened with China's 2008 milk adulteration scandal.

[thfuran]

You're asking how taxes and fees are different from criminal penalties? I guess the simplest way to put it would be that you go to prison for not paying enough of the one, whereas you'd go to prison for paying too much of the other.

[elihu]

Taxes work in some cases, but we do bans as well sometimes when it makes sense. That isn't authoritarianism; it's just regular governance. Or you could call it civilization.

In terms of climate change, there isn't really any budget of "safe" CO2 emissions left -- we've used it all up by largely ignoring the problem up until now.

The world can't realistically just stop using fossil fuels right now, because so much of our infrastructure depends on it. But we can stop wasting fuel on things we don't need. One of those things we don't need is the vast majority of air traffic that isn't transporting high-value time-critical cargo or getting people where they need to go to complete a specific job (and if it could have been done with a Skype call then no, it isn't a need).

[ClumsyPilot]

> You fix the externality by taxing the carbon emission at a level that covers the externality.

So the 'Forever chemicals' cannot be removed from the environment now, they are in the blood of thousands of people and in the water.

The fine should be infinite?

[jltsiren]

If you want to tax something, you have to define it, measure it, and report it. You need a system for collecting the taxes, a system for enforcing the collection, and a system for validating that the reported numbers are correct. You will need more regulations and more bureaucracy than if you had simply banned it.

Banning something is a solution that prevents some people from doing what they want. Taxing something is a solution that subjects a (potentially much) larger group of people to a reporting and tax burden and random inspections. If it's authoritarianism you are concerned about, you have to contrast the sizes of these groups and the potential harms from the banning and tax collection to determine which solution is worse.

[Dylan16807]

That taxation system already exists for jet fuel. Nothing new needs to be added.

[jltsiren]

Which is a tax on jet fuel, not on carbon emissions. If you raise the tax to cover the negative externalities, you create an incentive to use other fuels that may be less efficient and more harmful but cheaper. If you extend the tax to cover the use of all fuels in aviation, you need a mechanism to prevent people from using fuels bought for other purposes.

Regulation is difficult, especially when you are trying to outwit the market.

[Nextgrid]

> Must we permit everything that might be of benefit to someone, even if it comes at the expense of everyone else?

If we can offset "the expense of everyone else" (in this case via a carbon tax), why not?

[thfuran]

Assessing a tax doesn't actually clean the air. All it does is ensure that only the rich have the right to fuck everyone else over. If the government committed to funding carbon capture at a rate of at least as much as they would've in the counterfactual where there was instead a ban plus the additional amount funded by the carbon tax revenue, taxing the externality would probably be adequate redress, but that isn't ever going to happen.

[Nextgrid]

> Assessing a tax doesn't actually clean the air

Unless you use that tax to pay someone to clean the air?

[thfuran]

You have to both put the entirety of the tax towards it and ensure that the fact that you're funding it through the tax doesn't decrease the amount of additional funding you put towards it or else that decrease effectively decreases the tax rate (at least as far as carbon capture is concerned). The second part is harder than the first.

[pydry]

>The proper argument is for a carbon tax

The proper argument is to get a carbon tax first before unbanning anything like this.

And it's not on the political horizon so....

[denton-scratch]

Carbon taxes (as they exist now) are a con. You just buy some carbon credits from some company that is supposedly carbon-negative, because it plants forests somewhere so obscure that nobody checks.

And anyway, forests are not carbon-negative; all that lives must die. They're carbon-neutral.

[nwallin]

We do not have carbon taxes, we have carbon credits. Carbon credits are at best green political theater. At worst they're an effective means for the carbon economy (coal, oil, gas) to deflect efforts to get a carbon tax on the table, as evidenced by comments like this one.

Carbon taxes, on the other hand, are an effective solution to global warming.

[ianburrell]

Carbon tax != carbon credits. Carbon credits are part of emission trading approach. Carbon tax doesn't need credits cause uses money. Not being cheatable is one of the advantages of carbon tax.

[michaelmrose]

Offsets are basically mostly lies and nonsense. If your goal is to reduce emissions in absolute terms controlling it with taxes makes less sense than just limiting which unlike offsets actually does something.

[aziaziazi]

What is relevant is the inhabitability of the earth, not who pays what.

[panick21_]

> The faster the plane goes, the more fuel it consumes due to the drag increase by the square of the speed.

... at the same altitude.

[crazygringo]

Oh interesting.

Looking it up, the Concorde flew at 60,000 ft, compared to normal planes at 30,000 ft.

And atmospheric pressure at 60k ft is less than a quarter of what it is at 30k.

Is it possible to fly twice the speed of a regular aircraft but without using that much more fuel, by flying higher? Or does the plane have to burn even more fuel to get up to that altitude and maintain lift in a thinner atmosphere?

[coderenegade]

Yes. It's one of the reasons liquid hydrogen is potentially a better fuel than kerosene. You need a larger volume of fuel, but you carry less mass which makes cruise more efficient, and hydrogen burns so lean that you can fly around twice as high. You would cruise around 70k ft, instead of the usual 35k.

You do need more energy to go that high and fast, but it take a bit of analysis to figure out if it's problematic. Most likely it would be driven by the mission profile as to whether or not the trade-off is worth making.

[banana_giraffe]

One of the bits of trivia about the Concorde: It nominally flew at 60k feet, but a "cosmic radiation" sensor was added, and if went above some limit, they would descend to 47k feet or lower.

[57FkMytWjyFu]

Not sure the quotes are necessary. That's exactly what it was.

"In the days when the supersonic transport was in active service, and cruising at between 60 and 68,000 feet, the estimated radiation received by the crew was 50-130 mSv/yr. thus, obviously, as newer generations of aircraft cruise ever higher, by the time we reach altitudes above 60,000 feet, it is entirely possible that, especially with crews flying trans-Atlantic or transpolar routes, the acceptable maximum safe dose of radiation per year will be exceeded. In addition, these numbers do not take into account the possibility of pregnancy in female crewmembers. "

See Van Allen Belts.

[NoZebra120vClip]

I just imagined this as Nethack, where a pilot readout suddenly says, "Oh wow! Everything looks so cosmic!" and then everyone/everything in the cabin begins hallucinating.

[gorgoiler]

I haven’t ever thought of cosmic radiation in that way before. It would be interesting to know more data on the rate of bit flips when flying at altitude.

If I edit my photos on the flight home, am I more likely to corrupt my files with bit flips?

[jeffbee]

Yes, even at normal flight altitudes rays energetic enough to flip bits are hundreds of times more common than at sea level. It would be a fairly poor idea to put your new datacenter in La Paz (or Utah for that matter ... attention: NSA).

[gallexme]

Not twice as much I think, but it's definitly more efficent to fly higher if it's in the efficent envelope of these engines , just alone cause winds up there are way way faster which can be very favorable, because of the Coriolis Effect

[klyrs]

Take it just a little further: why not ballistic flight? Sure, they call it the "vomit comet" for a reason but with the right marketing and some investment in gravol, I feel like the zero g portion of the flight should be a selling point.

[dguest]

There's also no reason to keep everyone in the same capsule once you're in space: you could have multiple independent reentry vehicles. Fire off a rocket somewhere West of Chicago, send a dozen people to Stockholm, a dozen to London, a bit of cargo to Prague.

As long as nothing ever seems to be mysteriously off course and heading for Moscow it sounds like a great idea. Is it easy to distinguish a ballistic missile full of passengers from the more bad kind?

[klyrs]

Fit them with transponders and broadcast schedules well in advance of flights. The destination can veto a flight at any time before launch, and have inspectors at the point of launch. In this way, Moscow (etc) could keep arrivals down to a limit that their antiballistic defenses can handle, and ensure that only people-carriers are being put into their airspace. An attacker would be limited to a single kinetic suicide attack before their target goes on high alert.

But I was more curious about the fuel efficiency...

[greedo]

The Pentagon is investigating using SpaceX's Starship for point to point travel...

[Retric]

Which is offset by the need to climb through 30,000 ft on the way to 60,000 ft.

It turns out that higher cruising altitude isn’t nearly as useful as atmospheric pressure might suggest. Aircraft end up optimized for their cruising altitude, but there’s a lot of tradeoffs when targeting a higher altitude.

[zamnos]

Doesn't that also imply that it would be possible to fly a modified plane at the regular speed of a regular aircraft at that much higher altitude, and use way less fuel? Airlines' main cost driver is fuel, so it seems like they'd take advantage of that as much as possible.

[t0mas88]

It's not that easy.

If you go higher, the speed of sound decreases so you have to go slower to avoid going above the critical Mach number for your aircraft. Normal airliners have to stay quite a bit below Mach 1 to avoid any part of the airflow going supersonic, since that would create big issues like shock waves making the aircraft uncontrollable.

But due to the air being really thin, you also have to go faster. Otherwise your wings will not generate enough lift to keep flying.

At some point you cannot go faster and you cannot go slower, that effect is called Coffin Corner and limits how high a subsonic airliner could fly: https://en.wikipedia.org/wiki/Coffin_corner_(aerodynamics)

[barelysapient]

I think that would require a different plane design since they'd have less lift at that altitude.

[bombcar]

There’s a balance. And the Concorde had to have weird stuff to get that high but yes - you can get better performance higher to a point.

[mpweiher]

IIRC, that's what made jet planes possible in the first place. Jet turbines in general, and particularly the first ones, were horribly inefficient compared to props. However, they let you fly so much higher that it kind of canceled out.

The turbofan engines of today mitigate this inefficiency by, in essence, strapping a big prop in front of the turbine, except we call it a fan.

[Brian_K_White]

I think it's called a fan and not a prop, because it's a fan and not a prop.

Props employ lift like a wing. Fans are screws.

It's really a spectrum where most props & fans actually posess at least a little of both properties, and there are some in the middle that had to simply be called propfans.

[programmer_dude]

Turboprop is also a thing BTW.

[looping__lui]

Funnily enough the SR71 at Mach 3.5 had a better mpg than a Boeing 747 below Mach 1. It’s kind of hard to compare apples to apples here - but at supersonic speed, different engine technology can be used with better fuel efficiency…

[AlphaCharlie]

The SR71 was flying at a much higher altitude to achieve lower drag and fits 2 pilots, 0 commercial passengers.

If you want to compare apples to apples, I suggest you refer to the 2 metrics I mentioned: - gallons of fuel per miles flown - fuel used per passenger

One without the other is a useless comparison as you pointed out.

[looping__lui]

U miss the point entirely that supersonic planes work differently from “traditional” subsonic planes. Just assuming that “faster equals less fuel efficient” is not really correct. Turbofan engines are kind of draggy and not so fuel efficient close to Mach 1. Ramjets change your equation… :-)

[taeric]

The point is poorly made. Would be like talking about how fuel efficient the space station is for it's speed. Can only work if you ignore the trip to that steady state.

So, for the blackbird, how does it do on take off? You know, when it is literally leaking fuel? :)

[looping__lui]

Maybe you just wanted to understand the point in a certain way so you could argue about it?

[taeric]

Certainly fair. I can't see any world where the comparison is relevant, though. :(

Down thread it was pointed out that sports cars are more efficient than busses. Per vehicle. This is about the same idea, at best.

[dragonwriter]

> Funnily enough the SR71 at Mach 3.5 had a better mpg than a Boeing 747 below Mach 1.

The SR-71 had a maximum takeoff weight of 140,000lbs.

The 747 has a maximum takeoff weight of 735,000-910,000 lbs, depending on model.

That helps quite a bit for the former using less fuel per mile.

[thfuran]

And a considerably higher percentage of the 747's weight is passenger/cargo as well.

[taeric]

You also have to compare getting to that speed. And, of course, the comparison is dead when done per passenger. Might as well compare a missile in there, or a drone.

[post-it]

A Ferrari probably has better fuel efficiency than a bus, yeah.

[dsr_]

True. An average city bus gets 7 mpg; an 812 Superfast gets 13mpg.

The bus wins when carrying 3 or more passengers besides the driver. And in a city with dedicated bus lanes, the bus may win for route speed, too.

[looping__lui]

And I guess the brains behind a Ferrari enjoy their work more than engineers designing said bus. And Ferraris will attract more attention than a bus. Maybe some things are just unnecessary. Conquering the useless and doing unnecessary things is what keeps me sane and happy. But our mileage on that topic might vary.

[ClumsyPilot]

> And I guess the brains behind a Ferrari enjoy their work more than engineers designing said bus

If we want to improve lives of workers, I am game, but can we start by helping all the amazon can drivers that pee in a bottle?

[looping__lui]

Maybe start with taxing the rich higher taxes, have minimum wage, maximum allowable working hours and all that stuff. The country I live in does that. You unemployed with three kids? Government pays your housing, free education for school and college (which is the same for rich and poor) and free healthcare.

Why does designing a Ferrari have anything to do with your broken society? It’s not about the Ferrari - it’s about middle class upwards being cheap. Pay higher taxes and your problems on “improve live of workers” will go away.

I pay approx. 60-65% on my gross income. Do the same and we can start talking again.

[looping__lui]

… and don’t be cheap about “oh no, I cant because I can’t change the tax system”. Start tipping everyone rendering you a service until 65% of your gross income is gone every month. That UPS driver picking up your package - here’s 50$. That school teacher staying late at a parent conference. Take my money. The lady in the supermarket - take the $100 because I don’t need it. At least you can feel good about it because you do it voluntarily. You can fix it with (your own) money.

[Already__Taken]

Doing what? sat at 70mph, yeh probably. stop/starting chundling around town I guarantee not.

[speed_spread]

Are you optimizing for throughput or latency?

[SkyMarshal]

Probably also because it flew much higher with less air density and drag.

[lfowles]

It also only carried 2...

[tormeh]

Drag also works differently at supersonic speeds.

[gleglegle]

Per passenger?

[Retric]

No.

[tormeh]

> The faster the plane goes, the more fuel it consumes due to the drag increase by the square of the speed

This is not actually true. Drag is at max at around mach 1. After that it goes down again. If you go fast enough you can be very efficient.

[avereveard]

Drag goes back from the transonic peak but not below what was at subsonic speed.

The gain comes from being able to fly in thinner air if the plan be is designed to survive the the transonic regime and supercuise, because mach speed becomes lower higher you fly and the air thinner, so lift available to subsonic planes is limited

[ndr]

If you care about emissions then limit emissions.

Limiting proxy metrics, almost as speed instead of noise, when the limit is pretty easy to enforce doesn't do anything other than stifling innovation.

[seventytwo]

If we had a robust carbon pollution tax, then this wouldn’t be a problem. The emissions would be priced into the ticket, and we could all (theoretically) fly easy.

The root of all this is really just that the pollution from fossil fuels needs to be paid for.

[eru]

> The faster the plane goes, the more fuel it consumes due to the drag increase by the square of the speed. In a world where fossil fuel is needed to fly airplanes and where oil is causing a destruction of the world we inhabit, it's dangerous to suggest we should make the flying industry polluting more than they already are.

Just tax fuel to price in the externality and let people decide how much they want to spend?

> Flying faster than mach-1 to save time will be reserved to a small elite. How does it benefit the masses?

The elite are also people.

[geysersam]

We're soo far from this though. Air fuel is taxed very little due to the Chicago convention.

How much should it be taxed to factor in the external cost?

[eru]

> How much should it be taxed to factor in the external cost?

I don't know. But that can be treated as a technical problem to figure out. (Problems being technical is good! Much more tractable than political or social problems.)

> Air fuel is taxed very little due to the Chicago convention.

I'm not quite sure how much the Chicago convention would hinder a clever law drafter. Judging by what I can see at Wikipedia on it, I would imagine you could technically tax not kerosene itself, but the burning of kerosene inside your airspace.

[cat_plus_plus]

You are again trying to control the wrong thing - speed vs noise or carbon emissions. Price carbon and let details sort themselves out. Also by the same token, small elite will not generate a lot of carbon in the big picture.

[raincole]

Maybe it should be replaced with a fuel-per-mile limit?

[sroussey]

Maybe fuel per passenger?

[fortran77]

Yes! And some passengers are more expensive to transport because of their mass. They should pay more.

[camel_gopher]

“ n order to slow the rate of the damage, the Federation Council shared the findings with all known warp-capable species and imposed a speed restriction of warp factor 5 on all Federation vessels in all but extreme emergencies. The areas of space most damaged by that point were restricted to essential travel only.”

[bilsbie]

But we still need an exception for billionaires and climate activists to travel to climate change summits.

[TylerE]

You can get around that by flying higher, where the air is thinner. This is easier if you faster.

[paulcole]

Everybody sure can find something to handwring over when it comes to climate change. We fucked the environment pretty good and we’ve barely begun to feel the effects.

Let’s just fly around really fast and enjoy it for the next century or os.

[davidw]

Seems like a good job for a carbon tax to change the economic calculations involved. Perhaps for some, the speed would be worth it, but they'd be paying for it.

[hanniabu]

The more credits they buy, the more expensive they should become

[mLuby]

Yes, because the carbon-emitting companies are having to buy those credits from carbon-reducing companies.

The more demand there is, the more incentive there is for carbon-reducing companies to arise.

[dieselgate]

if we’re talking passenger miles per gallon then commercial planes are often more efficient than vehicular transport, especially when considering vehicles with only 1 or 2 passengers