Is killing the boom the key to supersonic air travel?(bbc.co.uk)
bbc.co.uk
Is killing the boom the key to supersonic air travel?
https://www.bbc.co.uk/news/business-44795639
117 comments
Current aircraft are significantly slower vs 50 years ago due to fuel economy issues. At 30,000 feet airlines could fly just under 678 mph, but they actually ~575 mph. This pushes up the benefit of supersonic flight.
On top of that the top 0.1% is both larger and more wealthy making filling ~50 seats a flight at 30,000+$ a pop easier than you might think. Drop that into $5,000 territory and some people would this every week.
IMO it's actually business jets that are the best market. They fly fewer trips making fuel less of an issue.
On top of that the top 0.1% is both larger and more wealthy making filling ~50 seats a flight at 30,000+$ a pop easier than you might think. Drop that into $5,000 territory and some people would this every week.
IMO it's actually business jets that are the best market. They fly fewer trips making fuel less of an issue.
Also, above a certain level of affluence, a person's time, is valued over money. Taking a private jet might be a good deal for anyone making the big bucks.
”Boom Supersonic are planning a 55 passenger plane. That is laughable as a commercial proposition.”
Do you feel that is too big, or too small? The market for supersonic travel is likely to align with the very high-end, private jet market. Those who want to get somewhere fast and don’t care what it costs.
It may be easier to overcome noise issues with a smaller design, too.
Do you feel that is too big, or too small? The market for supersonic travel is likely to align with the very high-end, private jet market. Those who want to get somewhere fast and don’t care what it costs.
It may be easier to overcome noise issues with a smaller design, too.
My experience with private aviation suggests that getting somewhere exactly when they want, flying into airports closer to their destination, stepping directly out of/into ground transportation and, to a lesser extent, having privacy en route are significant drivers for the private aviation crowd.
Cessna is killing the X, the fastest civilian airplane, in favor of slower airplanes. I'm not convinced that supersonic transport to/from major airports is going to threaten business/private jet aviation.
Cessna is killing the X, the fastest civilian airplane, in favor of slower airplanes. I'm not convinced that supersonic transport to/from major airports is going to threaten business/private jet aviation.
Assuming noise regulations can be met, is there any reason why
a small supersonic aircraft couldn't operate private flights into those same airports? Or do supersonic airframes need longer runways for higher-speed take offs and landings?
All of today's supersonic aircraft need runways longer than a mile. It is my belief that these projected supersonic aircraft will still likely need a mile or more.
There are 19K runways in the US, the vast majority of which have a longest runway under 4000'.
There are 19K runways in the US, the vast majority of which have a longest runway under 4000'.
It should have sufficient power reserves to work with a normal 747-style runway. And starting/landing is done subsonically anyway, as one does not want wheels outside at those speeds.
I see no reason this should not work.
I see no reason this should not work.
It's too small for a commercial flight. A commercial flight needs to carry enough people to be cheaper than a private flight. With the exception of exceptionally long flights, private flights can match the total travel time of a commercial flight on a much faster plane because they can can match the passengers' preferred start and end locations and the passengers' preferred schedule much more closely than a commercial flight can.
Supersonic flights will be very much a premium fare option, due to the significant increase in energy use and fuel required for supersonic flight.
Make a supersonic aircraft too big and you risk not being able to find enough passengers willing to pay fares that make it viable - which is one of the issues that killed Concorde.
Make a supersonic aircraft too big and you risk not being able to find enough passengers willing to pay fares that make it viable - which is one of the issues that killed Concorde.
Nope, killing Amdahl's Law is the key to supersonic air travel.
If it takes me 45 minutes to get to the departure airport, where I have to be one hour ahead of time to get through baggage check and security, and it takes 2 hours to get to my destination from the landing airport, then cutting a 4 hour flight to 2 hours is only 34% faster.
Like, fix the transportation and traffic problems around the airports and the logistical delays first, then brute-force the actual flight time.
If it takes me 45 minutes to get to the departure airport, where I have to be one hour ahead of time to get through baggage check and security, and it takes 2 hours to get to my destination from the landing airport, then cutting a 4 hour flight to 2 hours is only 34% faster.
Like, fix the transportation and traffic problems around the airports and the logistical delays first, then brute-force the actual flight time.
> fix the transportation and traffic problems around the airports and the logistical delays first, then brute-force the actual flight time
Why this sequence and not the other way around, or both at the same time?
The two don't seem to be competing for any resources, other than the highest-level ones like money. In some cases, the airport logistics problem may be intractable or take too long (witness BER).
I also suggest your times are slightly off, in the context of the target market. I doubt someone paying that much would need the full hour (though as little as 30 minutes might be a stretch if we're counting departure time not boarding time).
I also think, however, that lowering a 4 hour (gate-to-gate) flight from 4 hours to 2 hours is unrealistic, and is too short a flight to make sense for supersonic, anyway. IIRC, Boom was looking to halve the 7-hour JFK-LHR hop, comparable to Concorde.
Where it would seem to be far more attractive is the much longer flights, such as trans-Pacific, where the overall time is much longer, a higher portion of gate-to-gate (and door-to-door) time is at maximum cruise speed (shaving 8 hours off a 14+ hour SFO-SYD could save a full day of travel). Even Europe to the US West Coast would be significant, which relates to the premise of the article.
Why this sequence and not the other way around, or both at the same time?
The two don't seem to be competing for any resources, other than the highest-level ones like money. In some cases, the airport logistics problem may be intractable or take too long (witness BER).
I also suggest your times are slightly off, in the context of the target market. I doubt someone paying that much would need the full hour (though as little as 30 minutes might be a stretch if we're counting departure time not boarding time).
I also think, however, that lowering a 4 hour (gate-to-gate) flight from 4 hours to 2 hours is unrealistic, and is too short a flight to make sense for supersonic, anyway. IIRC, Boom was looking to halve the 7-hour JFK-LHR hop, comparable to Concorde.
Where it would seem to be far more attractive is the much longer flights, such as trans-Pacific, where the overall time is much longer, a higher portion of gate-to-gate (and door-to-door) time is at maximum cruise speed (shaving 8 hours off a 14+ hour SFO-SYD could save a full day of travel). Even Europe to the US West Coast would be significant, which relates to the premise of the article.
I think the only way to kill the boom is to change the aerodynamics of the plane at different flying conditions. The only way to do this is to change what the air "sees" when it hits the planes wing surfaces by changing the turbulent and laminar regions. Unfortunately most methods are not quite there yet.
I would like to see supersonic travel come back.
But I would LOVE it if we could find a way to speed up the time spent at the airport. The amount of time I spend traveling to the airport, dropping off bags, queuing for security, getting pulled aside because I forgot I was wearing a belt that day, waiting for the gate to open, getting on a train to the gate, queuing to board the gate, getting on a BUS to the plane, queuing to get on the plane, waiting to put my overhead bags in the bins, waiting on the tarmac for the plan to find a free slot on the runway.
In the future I still have to do all this before we finally take off and travel at supersonic speed (yay), but then I land and basically have to do it all again.
Most of the time spent traveling by air is spent on the ground.
But I would LOVE it if we could find a way to speed up the time spent at the airport. The amount of time I spend traveling to the airport, dropping off bags, queuing for security, getting pulled aside because I forgot I was wearing a belt that day, waiting for the gate to open, getting on a train to the gate, queuing to board the gate, getting on a BUS to the plane, queuing to get on the plane, waiting to put my overhead bags in the bins, waiting on the tarmac for the plan to find a free slot on the runway.
In the future I still have to do all this before we finally take off and travel at supersonic speed (yay), but then I land and basically have to do it all again.
Most of the time spent traveling by air is spent on the ground.
This is exactly the reason why I usually prefer a 6-hour train ride to a 1-hour flight (at least in Germany, Austria, Switzerland).
Train: Go to the station (near city center), arrive 10 mins before train departs, get on the train, read/work/eat/drink for 6 hours, get off the train. And then you are already at the city center of your destination!
The total time spent when flying might be shorter (4.5-5 hours), but that is not worth the hassle.
Train: Go to the station (near city center), arrive 10 mins before train departs, get on the train, read/work/eat/drink for 6 hours, get off the train. And then you are already at the city center of your destination!
The total time spent when flying might be shorter (4.5-5 hours), but that is not worth the hassle.
So much this. Not to mention the reduced environmental impact. Flying is absolutely catastrophic in terms of greenhouse gas emissions, and the Paris accord doesn't cover even a fraction of it! (because flying occurs in "international space" and so it doesn't appear on any country's "balance sheet"... atrocious.)
> Flying is absolutely catastrophic in terms of greenhouse gas emissions
Uhm, flying is OK in terms of emissions per passenger mile. Not as great as train, but better than driving solo in a gasoline car.
The problem is transcontinental flights. While they're OK in terms of efficiency per mile, the number of miles is staggering.
The problem is, those trips can't be made by train.
So in terms of flying, I think the main focus should be not to fly long distance if it can be avoided. Sure, it's much better to take the train if possible, but if you fly between countries within europe a dozen times a year, that's not a catastrophe.
Uhm, flying is OK in terms of emissions per passenger mile. Not as great as train, but better than driving solo in a gasoline car.
The problem is transcontinental flights. While they're OK in terms of efficiency per mile, the number of miles is staggering.
The problem is, those trips can't be made by train.
So in terms of flying, I think the main focus should be not to fly long distance if it can be avoided. Sure, it's much better to take the train if possible, but if you fly between countries within europe a dozen times a year, that's not a catastrophe.
I know Boeing proposed Methane turbofans, and they were estimated to have 60% less carbon emissions and cheaper than jet fuel - after eating the large development and infrastructure costs. You could take this even further, producing Hydrogen from clean electric energy is about three times more expensive than methane for the same energy content, leading to a moderate increase in the cost of even a low cost ticket.
But as with all radically new technology, there needs to be a strong industry, government and consumer push. The program that produced the Methane turbofan concept (SUGAR Freeze) has lost any political appeal.
But as with all radically new technology, there needs to be a strong industry, government and consumer push. The program that produced the Methane turbofan concept (SUGAR Freeze) has lost any political appeal.
Costs aside, wouldn't replacing carbon emissions with methane be drastically worse? Doing a casual search says that methane is 2000-3000% more potent as a GHG.
I assume the methane would be the fuel, not the byproduct.
I imagine you won't combust 100% of the fuel. So wouldn't it be both.
Pure methane is a bunch of molecules with just one carbon, which simplifies things a bit vs. a cracked and heterogeneous mix of longer chain (10+) molecules.
You can incompletely combust a 10-carbon molecule and wind up with other hydrocarbons but if you burn up CH4, you're definitely just getting one CO2.
You can incompletely combust a 10-carbon molecule and wind up with other hydrocarbons but if you burn up CH4, you're definitely just getting one CO2.
>The problem is, those trips can't be made by train.
Transcontinental flights (one side of the continent to the other, see [1]) can usually be taken by train. You probably mean intercontinental flights.
[1] https://en.wikipedia.org/wiki/Transcontinental_airspeed_reco...
Transcontinental flights (one side of the continent to the other, see [1]) can usually be taken by train. You probably mean intercontinental flights.
[1] https://en.wikipedia.org/wiki/Transcontinental_airspeed_reco...
You're being pedantic. One can travel from New York to San Francisco (well, Emeryville) by train but it's going to take multiple days and, even if you handwave the existence of high-speed rail through two continental divides among other things, it's a very long trip. That's never going to be a mainstream replacement for even a subsonic 5 to 6 hour flight between a multitude of east coast-west coast city pairs.
If there were high-speed trains that could make cross-US trips in, say, 15 hours, and at comparable or cheaper cost vs. airplanes, I can imagine there might be demand. I would be willing to take those overnight.
But even if we could replace most <500 mile flights along the most popular routes (starting by connecting cities up and down the coasts), it would be a huge win as far as fuel economy is concerned.
But even if we could replace most <500 mile flights along the most popular routes (starting by connecting cities up and down the coasts), it would be a huge win as far as fuel economy is concerned.
And you're being parochial. Who said "continent" was limited to North America?
The claim was that the trip can't be made, not that it can be made but is undesirable as compared with alternatives.
The claim was that the trip can't be made, not that it can be made but is undesirable as compared with alternatives.
> The problem is, those trips can't be made by train.
They can't now, but they could be. All that is required is a level of capital investment that can't ever be recovered while in competition with air and sea-surface travel...
The transatlantic tunnel has been a sci-fi fantasy since 1895. It could cost as little as $500 billion today.
They can't now, but they could be. All that is required is a level of capital investment that can't ever be recovered while in competition with air and sea-surface travel...
The transatlantic tunnel has been a sci-fi fantasy since 1895. It could cost as little as $500 billion today.
> Not as great as train, but better than driving solo in a gasoline car.
It was my understanding that driving is better for shorter trips, because the overhead of taking off and landing is significant. I don't have a source. IIRC I read this in "Doing Good Better."
It was my understanding that driving is better for shorter trips, because the overhead of taking off and landing is significant. I don't have a source. IIRC I read this in "Doing Good Better."
Is it still competetive vs car for supersonic flight?
I'll point out that although it's indeed atrocious compared to a train ride, flying is still more efficient than driving a car. So if traveling is required and you're debating between driving vs. flying (say SF <-> LA), you should prefer flying unless you can carpool. I don't know the exact numbers since it depends on where you're going and what plane/airline you fly, but I would expect around 50-75 MPG for a reasonably full airplane [1], whereas your car might be more like 25-30 MPG on the highway, so you'd want at least 2-3 (ideally 4) people in the car to make it more efficient.
However the thing about flying is of course that it burns fuel at a much, much faster rate, so if it means the difference between you driving to workplace A vs. flying to workplace B regularly, then you'll be burning one hell of a lot more fuel by flying.
[1] https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft#Airli...
However the thing about flying is of course that it burns fuel at a much, much faster rate, so if it means the difference between you driving to workplace A vs. flying to workplace B regularly, then you'll be burning one hell of a lot more fuel by flying.
[1] https://en.wikipedia.org/wiki/Fuel_economy_in_aircraft#Airli...
Interestingly, the efficiency ratio you suggest appears to be reflected in the ratio between the overall cost (including ground transportation at the other end) of flying SFBA-SoCal and driving.
Whenever I've spot-checked, the break-even is at 2 people, which tends to make flying more attractive for time/fatigue reasons (only barely, at some points in history) even for 2, and sometimes worth the cost premium for 3. For a family of 4 or more, even with the increased fuel cost (but generally not other operating costs) of something like a minivan, driving saves too much money to pass up.
Whenever I've spot-checked, the break-even is at 2 people, which tends to make flying more attractive for time/fatigue reasons (only barely, at some points in history) even for 2, and sometimes worth the cost premium for 3. For a family of 4 or more, even with the increased fuel cost (but generally not other operating costs) of something like a minivan, driving saves too much money to pass up.
That's interesting, thanks for mentioning this!
That’s true today. But in the coming years and decades, ground transport will be largely electrified and it’s per-mile emissions greatly reduced.
Hopefully, aviation can be electrified too one day (or it’s emissions reduced with hybrid technology), but unlike ground transport, the technology is not quite here yet.
Hopefully, aviation can be electrified too one day (or it’s emissions reduced with hybrid technology), but unlike ground transport, the technology is not quite here yet.
Hybrid tech doesn't help at all with with planes. There is no braking energy to be regained and batteries are too heavy. It has no place there until battery energy density approaches that of fuel, which would require a huuge breakthrough of some kind.
The idea behind a hybrid aircraft is that eFans (electric fans) are more energy efficient than a turbofan, so you can burn less fuel for a given journey.
Companies including Airbus, Siemens, and Rolls Royce are actively working on this technology with a view to have working prototypes in the early 2020s.
Besides that, there is some "braking" energy to be recaptured during descent or when slowing the aircraft. This technology already exists today: The Pipistrel Electro can regen it's battery during descent. This is similar in principle to the ram air turbine (RAT) in conventional aircraft.
Companies including Airbus, Siemens, and Rolls Royce are actively working on this technology with a view to have working prototypes in the early 2020s.
Besides that, there is some "braking" energy to be recaptured during descent or when slowing the aircraft. This technology already exists today: The Pipistrel Electro can regen it's battery during descent. This is similar in principle to the ram air turbine (RAT) in conventional aircraft.
Well thanks for the pertinent info. I was pretty sure of myself that the cost benefit ratio wasn't there but if there are engineering efforts towards it there's at least potentially some merit.
I wonder, does the efficiency gain from efans and a generator apply to a single engine setup as well as it does to multi engine setups?
I wonder, does the efficiency gain from efans and a generator apply to a single engine setup as well as it does to multi engine setups?
With battery capacities being what they are you'll also have to hang tight for the moment when they stretch long enough to allow you to even have the choice of driving to the same place you can fly. (Or swap batteries on the way somehow... not sure how well that would work.)
This is already solved in technology terms. Battery capacities and charging speeds are already good enough for almost all long-distance travel scenarios.
It’s now just a case of getting costs down and infrastructure built out. But that’s the easy part.
It’s now just a case of getting costs down and infrastructure built out. But that’s the easy part.
> his is already solved in technology terms. Battery capacities and charging speeds are already good enough for almost all long-distance travel scenarios.
Really? It seems to me that decent EV ranges are around 150mi right now, with the best ones going to 300mi... meaning they generally might get you halfway from (say) SF to LA, and you can bet that none of them will get you all the way. And that's not even that long of a distance, depending on what your standards are. Now charging times run into multiple hours, right? How is that even remotely close to gasoline?
Really? It seems to me that decent EV ranges are around 150mi right now, with the best ones going to 300mi... meaning they generally might get you halfway from (say) SF to LA, and you can bet that none of them will get you all the way. And that's not even that long of a distance, depending on what your standards are. Now charging times run into multiple hours, right? How is that even remotely close to gasoline?
Charging times are around 45 minutes today for 250-300 miles of travel. Most people want to take a break after 4-5 hours of driving anyway, so it’s just a case of having chargers in the right locations.
The new generation of 350kW / 800V chargers will bring that down into the 15-20 minute range.
The new generation of 350kW / 800V chargers will bring that down into the 15-20 minute range.
> Most people want to take a break after 4-5 hours of driving anyway
I realize I'm not most people (I love to drive), but this seems like it's bordering on extraordinary-claim territory. I don't actually expect evidence, since this would be the kind that's particularly difficult to gather (you could ask people, but what people say doesn't necessarily translate to what they do).
Regardless, it seems unlikely to me that anyone would want to be forced to take a break at the 4 hour mark rather than waiting for their destination at the 5 hours mark (e.g. SJ-LA).
I realize, of course, that it's just a matter of (not that great a) degree between 20 minutes every 300 miles for charging versus 10 minutes every 400 miles for fueling. However, because we're not even there yet for a comparably-priced/affordable electric car, it may be premature to think that way.
I realize I'm not most people (I love to drive), but this seems like it's bordering on extraordinary-claim territory. I don't actually expect evidence, since this would be the kind that's particularly difficult to gather (you could ask people, but what people say doesn't necessarily translate to what they do).
Regardless, it seems unlikely to me that anyone would want to be forced to take a break at the 4 hour mark rather than waiting for their destination at the 5 hours mark (e.g. SJ-LA).
I realize, of course, that it's just a matter of (not that great a) degree between 20 minutes every 300 miles for charging versus 10 minutes every 400 miles for fueling. However, because we're not even there yet for a comparably-priced/affordable electric car, it may be premature to think that way.
I agree it was a little harder to swallow but it wasn't really "extraordinary". It's pretty normal to take breaks to stretch, eat, use the restroom, etc. during a 5+-hour ride. On top of that, given how doctors say you should get up and walk around in an airplane every few hours at least, I imagine it's not healthy to drive 5+ hours nonstop on the road either, in which case you arguably should be taking a break if you're one of those who doesn't.
Hard to swallow doesn't at least border (which is what I said) on extraordinary for you? :)
All those "shoulds" being forced on a consumer are likely to be disincentive to purchase, no matter how "bad" or irrational that might seem.
All those "shoulds" being forced on a consumer are likely to be disincentive to purchase, no matter how "bad" or irrational that might seem.
"it seems unlikely to me that anyone would want to be forced to take a break at the 4 hour mark rather than waiting for their destination at the 5 hours mark (e.g. SJ-LA)."
If your destination is only 1 hour further away, then you're only going to need about a 10 minute charge, not the full 45 minutes. And you can stop pretty much anywhere en route where there are chargers available, it doesn't have to be at the 4 hour mark. Plenty of flexibility there.
"we're not even there yet for a comparably-priced/affordable electric car"
I agree, but they're getting close already when you consider lifetime costs including fuel and maintenance. And the more driving you do, the more financial sense an EV makes. That's why we're seeing taxi operators embracing EVs enthusiastically.
If your destination is only 1 hour further away, then you're only going to need about a 10 minute charge, not the full 45 minutes. And you can stop pretty much anywhere en route where there are chargers available, it doesn't have to be at the 4 hour mark. Plenty of flexibility there.
"we're not even there yet for a comparably-priced/affordable electric car"
I agree, but they're getting close already when you consider lifetime costs including fuel and maintenance. And the more driving you do, the more financial sense an EV makes. That's why we're seeing taxi operators embracing EVs enthusiastically.
> And you can stop pretty much anywhere en route
This is speculative and doesn't affect the emotional purchase decision today.
> Plenty of flexibility there.
Perhaps by some objective measure, but, again, that ignores the emotional component.
> but they're getting close already when you consider lifetime costs including fuel and maintenance
That's as may be, but lifetime costs are irrelevant if the barrier to entry (practical or emotional) is too high in the form of purchase cost.
It's not even necessarily irrational to decide to pay what appears to be a higher lifetime cost if ones personal "interest" rate in the TVM calculation exceeds the standard/average one, due to a high opportunity cost or just a high borrowing cost.
This is speculative and doesn't affect the emotional purchase decision today.
> Plenty of flexibility there.
Perhaps by some objective measure, but, again, that ignores the emotional component.
> but they're getting close already when you consider lifetime costs including fuel and maintenance
That's as may be, but lifetime costs are irrelevant if the barrier to entry (practical or emotional) is too high in the form of purchase cost.
It's not even necessarily irrational to decide to pay what appears to be a higher lifetime cost if ones personal "interest" rate in the TVM calculation exceeds the standard/average one, due to a high opportunity cost or just a high borrowing cost.
All these security for air travel but not for a train which is also full of lot of people felt bizarre.
Well, the impetus for enhanced airport security was first the spate of hijackings in the late '60s to early '80s, and later 9/11.
While you can hijack a train, you can't fly it to a friendly country, and you can't fly it into a building, so it's a very different threat model.
While you can hijack a train, you can't fly it to a friendly country, and you can't fly it into a building, so it's a very different threat model.
[deleted]
Locking cockpit doors has already solved both those problems.
Germanwings would like to have a word with you.
Are you referring to this?
https://en.m.wikipedia.org/wiki/Germanwings_Flight_9525
https://en.m.wikipedia.org/wiki/Germanwings_Flight_9525
Yeah, the first officer locked himself in then started descent into a mountain.
But how does a suicidal pilot apply to airport security?
..more like a homicidal pilot.
To be frank about it, trains are a much softer target, since they can be derailed with an explosion on the track, or even a bit of welding.
Blowing up an airplane requires either bringing an explosive on board, or the use of a rocket-propelled grenade or full-on missile. Quite aside from the risks of hijacking mentioned in a sibling comment.
Blowing up an airplane requires either bringing an explosive on board, or the use of a rocket-propelled grenade or full-on missile. Quite aside from the risks of hijacking mentioned in a sibling comment.
However, blowing up a bomb on a cruising plane will probably kill everyone. Blowing up a bomb on a cruising train will probably not - many people will be far from the blast and derailing trains are more survivable than planes breaking up at altitude.
You can't hijack a train and take hostages to some other country; This was endemic in the 80s.
You also can't hijack a train and drive it into a building.
You also can't hijack a train and drive it into a building.
You can divert it remotely by dispatch if the route is fully signalled. Trains cannot travel except what rails direct them to.
But is this still true for airplanes, given the switch to hardened cockpit doors?
It is still true; Holding a train full of passengers hostage is foolish because there's no possibility that a train driver could disengage the rails.
Holding a plane full of passengers hostage is less foolish because the pilots/flight attendants can be bribed and bartered- it's not a technical impossibility to do certain actions, so there is more of an incentive.
Holding a plane full of passengers hostage is less foolish because the pilots/flight attendants can be bribed and bartered- it's not a technical impossibility to do certain actions, so there is more of an incentive.
Then you get Germanwings incidents
Which can't happen on trains and buses?
Buses, maybe. Trains: Nope. Doors are locked from the inside, usually aren't accessible while moving and even someone would get inside, well, you can't get off the tracks. You'll get a red signal and a forced braking shortly afterwards. It's really, REALLY hard (by design) to wreck something on purpose with a modern high speed train.
This is why electric trains are so nice: you can shut them off from the ground.
And in buses you can't really lock yourself out as a driver.
Which wasn't a hostage situation or a hijacking to get elsewhere, and it has nothing to do with the passenger security theater which is what this thread is about...
Shhhh, don't say it too loudly! The TSA is already trying to get their greasy fingers into train travel. :-(
I'm totally with you, but it is truly annoying the amount of subsidies the flight industry get. I've often taken trains across Europe due to my preference, but when the plane ticket is €20 and the train ticket is €400 it seems I'm fighting against the system.
> but it is truly annoying the amount of subsidies the flight industry get
Please could you illustrate some of those for me, as compared to rail?
Please could you illustrate some of those for me, as compared to rail?
UK here.
> Aviation is currently undertaxed, according to economists from the IMF and World Bank, compared to other forms of transport. Airlines pay no fuel duty and VAT is zero rated meaning that no tax is charged on sales and tax charged on inputs is refunded.
> ...
> CE Delft calculated in 2013 that the shortfall as a result of these two anomalies amounted to around €27 billion annually in Europe.
> ...
> At a global level, the World Bank and IMF favour a relatively low tax universally applied per tonne of CO2, which could then raise money for climate change mitigation.
> In the UK, the Liberal Democrat and Conservative coalition considered in 2010 replacing APD with a per plane tax to include freight aircraft and provide an additional incentive to airlines to fill empty seats. However, this was dropped following concerns, the Government claimed, about concerns that it could be challenged legally as representing a proxy fuel tax (contrary to bilateral air service provisions with other countries).
> Another alternative would be a form of taxation that discouraged frequent fliers.
https://www.aef.org.uk/issues/economics/taxation/
> Aviation is currently undertaxed, according to economists from the IMF and World Bank, compared to other forms of transport. Airlines pay no fuel duty and VAT is zero rated meaning that no tax is charged on sales and tax charged on inputs is refunded.
> ...
> CE Delft calculated in 2013 that the shortfall as a result of these two anomalies amounted to around €27 billion annually in Europe.
> ...
> At a global level, the World Bank and IMF favour a relatively low tax universally applied per tonne of CO2, which could then raise money for climate change mitigation.
> In the UK, the Liberal Democrat and Conservative coalition considered in 2010 replacing APD with a per plane tax to include freight aircraft and provide an additional incentive to airlines to fill empty seats. However, this was dropped following concerns, the Government claimed, about concerns that it could be challenged legally as representing a proxy fuel tax (contrary to bilateral air service provisions with other countries).
> Another alternative would be a form of taxation that discouraged frequent fliers.
https://www.aef.org.uk/issues/economics/taxation/
1. International airlines pay no tax on aviation fuel, despite their significant contribution to air pollution and climate change. In say, Europe, this represents a huge subsidy compared to ground transport, where fuel is heavily taxed.
2. Airports, particularly regional ones, are often owned by local governments and receive subsidies in order to encourage tourism and commerce in their region. In some cases, airlines receive direct subsidies from those airports in order to fly there.
3. Internationally, some airlines themselves are state-owned or state-subsidised. Gulf airlines such as Emirates and Qatar have been criticised for being significant beneficiaries of state subsidies.
This isn’t to say that rail isn’t subsidised too, of course. Even in countries where rail operates on a commercial basis, the physical infrastructure is usually government owned or financed in some way.
However, if airlines had to account for (and pay for) their environmental externalities, the costs of airline vs rail travel would work out very differently!
2. Airports, particularly regional ones, are often owned by local governments and receive subsidies in order to encourage tourism and commerce in their region. In some cases, airlines receive direct subsidies from those airports in order to fly there.
3. Internationally, some airlines themselves are state-owned or state-subsidised. Gulf airlines such as Emirates and Qatar have been criticised for being significant beneficiaries of state subsidies.
This isn’t to say that rail isn’t subsidised too, of course. Even in countries where rail operates on a commercial basis, the physical infrastructure is usually government owned or financed in some way.
However, if airlines had to account for (and pay for) their environmental externalities, the costs of airline vs rail travel would work out very differently!
> compared to ground transport, where fuel is heavily taxed
But isn't this basically a road tax? Fuel for agricultural machinery or industrial plants is also free of such taxes (typically).
But isn't this basically a road tax? Fuel for agricultural machinery or industrial plants is also free of such taxes (typically).
I traveled with the French TGV a couple times and it is absolutely astounding how amazing it is. Large comfy chairs, quiet train, you can walk around, plenty of room for activities. There's even a bar where you can hang out with fellow passengers!
Plus first class tickets are like $20 more expensive than normal tickets and totally worth it.
Although I almost missed it because I'm used to all the buffer time you get with airplanes. Train leaves at 10:45, you better be there at 10:40 or you're gonna miss the darn thing.
Plus first class tickets are like $20 more expensive than normal tickets and totally worth it.
Although I almost missed it because I'm used to all the buffer time you get with airplanes. Train leaves at 10:45, you better be there at 10:40 or you're gonna miss the darn thing.
Although I like our (maybe not for long) nationalized train system, I still have to mitigate your praises a bit :) .
One of my main issue is that train ticket are really expensive. Regional train are okayish, but TGV cost often way more than any other equivalent (plane/bus/car/...) and are sometimes not faster.
The second thing is that the network is historically completely centered around Paris. That lead to some very weird situation where, to go from the north-west to the south-west, you need to go all around France. And because of this, it is again faster and cheaper to just take a plane.
Finally, there is often delay or train being canceled, which is normal because lot more problem happen on the ground and such that when you are several thousand feet in the air, but they tend to communicate about it really badly. When your train have a problem, it is often really hard to know when you will have a new train, how much delay will you have, ...
On the other end, I agree with you. The train are so much comfortable. I really enjoy traveling in train way more than with any other form of transportation. I assume they are also a bit more ecological than cars and planes. The application of the SCNF to book ticket is also very good nowadays, never had a problem with it.
One of my main issue is that train ticket are really expensive. Regional train are okayish, but TGV cost often way more than any other equivalent (plane/bus/car/...) and are sometimes not faster.
The second thing is that the network is historically completely centered around Paris. That lead to some very weird situation where, to go from the north-west to the south-west, you need to go all around France. And because of this, it is again faster and cheaper to just take a plane.
Finally, there is often delay or train being canceled, which is normal because lot more problem happen on the ground and such that when you are several thousand feet in the air, but they tend to communicate about it really badly. When your train have a problem, it is often really hard to know when you will have a new train, how much delay will you have, ...
On the other end, I agree with you. The train are so much comfortable. I really enjoy traveling in train way more than with any other form of transportation. I assume they are also a bit more ecological than cars and planes. The application of the SCNF to book ticket is also very good nowadays, never had a problem with it.
Lol, try living in California. 6-12 hour plane ride to anywhere. Trains? We have them. But why would you when it takes literally days to cross the country.
That's not a problem of trains it's a problem of the US train infrastructure. As you can see in Europe or Japan trains can be very fast and very efficient.
Sure, but the distances between cities in a huge country like the USA tend to be much greater than in Europe or Japan. Even if you had high speed rail it’d still take a very long time to cross the continent!
High speed trains do exist, or are being built, in more densely populated US regions (eg Northeast corridor, California).
High speed trains do exist, or are being built, in more densely populated US regions (eg Northeast corridor, California).
The distances between cities in California or the upper East coast isn't. Both places have a high enough population density to support a good train network.
No one is suggesting that you take train from New York to LA but rather that you take a train from LA to San Francisco or Boston to New York. Similarly in Europe most people don't take a train from London to Rome but people will often take a train from London to Paris or Barcelona to Madrid. Any flight of 3 hours or less is usually faster and more comfortable as a train ride.
No one is suggesting that you take train from New York to LA but rather that you take a train from LA to San Francisco or Boston to New York. Similarly in Europe most people don't take a train from London to Rome but people will often take a train from London to Paris or Barcelona to Madrid. Any flight of 3 hours or less is usually faster and more comfortable as a train ride.
For those who don't know, people take trains between cities in the US Northeast Corridor all the time. In fact, that's pretty much Amtrak's only profitable region (money that it then loses in the rest of the country). And Amtrak actually has significant modernization plans in part because some routes are at capacity during busy times.
There would be even higher usage if Amtrak service in the region was actually good instead of just passable. The fastest service between New York and DC averages only 82 mph and it's even slower if you go past either of those cities. The allegedly "high-speed" service between New York and Boston averages only 66 mph. That's not even hitting the upper end of highway speeds.
There is very low population density between the LA and SF metro areas, which are roughly 350 miles apart (400 miles from city center to city center). This is one of the reasons that a HSR has been such a hard sell.
Big cities with nothing in-between is a good sell for HSR. Europe's two largest countries that have that population distribution pattern (France, Spain) rely heavily on very fast HSR (300-350km/h). The countries with more distributed, but also more dense population (UK, Germany) rely more on fast networks with more stops, but less maximum speed (200-250km/h).
It takes around 4-5 days to cross the US by train.
The problem is, the regular seats are shoulder to shoulder, there's no showers, and everyone shares a bathroom. Plus, they gouge you relentlessly with food rates.
It doesn't seem like it would be a fun experience at all due to those conditions (but would be fun otherwise).
Of course you could spend $1,000+ each way to get a "sleeper seat" which comes with a shower and meals but then it's like you're essentially paying $700 for a shower and a touch of privacy. It's just off putting to me based on principle.
The problem is, the regular seats are shoulder to shoulder, there's no showers, and everyone shares a bathroom. Plus, they gouge you relentlessly with food rates.
It doesn't seem like it would be a fun experience at all due to those conditions (but would be fun otherwise).
Of course you could spend $1,000+ each way to get a "sleeper seat" which comes with a shower and meals but then it's like you're essentially paying $700 for a shower and a touch of privacy. It's just off putting to me based on principle.
That's the exact same reason why nobody sane takes a train in France for anything that matters. Schedules violated every day, strikes, poor maintenance, and moreover, they killed almost all of the night trains, that were the cheapest option especially if you account for one night you save on accommodation.
Just the normal airport designs could be improved a lot, with no added technology. It doesn't take a genius to see how many airports have very long walking distances or oddly placed stairs etc.
Also, airlines for some reason don't want checked in luggage, since they price it so high. This means everyone travels with maximum hand luggage, and boarding takes a long time. The last people boarding usually can not find space in the overhead bin close to their seat. I wonder if they really are at the global optimum point with this. Checked in luggage is also notoriously unreliable (it travels to the wrong country or is thrown around with such force that everything is broken) which can ruin your trip.
Also, airlines for some reason don't want checked in luggage, since they price it so high. This means everyone travels with maximum hand luggage, and boarding takes a long time. The last people boarding usually can not find space in the overhead bin close to their seat. I wonder if they really are at the global optimum point with this. Checked in luggage is also notoriously unreliable (it travels to the wrong country or is thrown around with such force that everything is broken) which can ruin your trip.
Airports make a fair share of their money by passengers hanging around and spending money in shops and restaurants. This video is pretty interesting: https://www.youtube.com/watch?v=wdU1WTBJMl0
It's the uncertainty that leads to longest wait times.
If I have no suitcases to drop off, and it's at a quiet time, then I can arrive half an hour before departure, breeze through security, and get on the plane.
But if I have cases, or security _might_ be long, then I'm having to leave at least an extra half an hour in case of big queues, if not an hour. And that's a time-killer.
The "automated bag drop" that some airports do now has really sped things up, but I'm sure some more time could be cut there. Security is the main bottleneck nowadays.
If I have no suitcases to drop off, and it's at a quiet time, then I can arrive half an hour before departure, breeze through security, and get on the plane.
But if I have cases, or security _might_ be long, then I'm having to leave at least an extra half an hour in case of big queues, if not an hour. And that's a time-killer.
The "automated bag drop" that some airports do now has really sped things up, but I'm sure some more time could be cut there. Security is the main bottleneck nowadays.
The good news is most of the changes you want are political rather than technological. There's no law of physics or even of economics that prevents us from having airports where, once you have a ticket, you hand your luggage to a machine then stroll over to your departure gate and board the plane as soon as it is ready.
The bad news is that political changes need the cooperation of large groups of your fellow citizens.
The bad news is that political changes need the cooperation of large groups of your fellow citizens.
Some airports make a significant portion of the revenue from the long wait between security and take off (e.g. Heathrow where they only show departure information 45 mins before leaving and you are surrounded by shops).
Agreed. I think self driving technology can help here. I imagine a lobby area where you check-in, go through passport and baggage control, then board a pod that securely takes you right on the tarmac, to the mobile ladder adjacent to your half of the plane.
The whole duty free forced march -> endless tread mills -> gate -> bus routine is harrowing busy work. It creates multiple choke and synchronization points, thus multiple queues: you queue to enter the gate, than wait for everybody to board the bus, then queue again as people take their seats and place the luggage in the overheads.
It's a telling sign of how bad the current system is, when boarding on a single front door is considered a large speed up. A pod can take you to the right door in real time, gradually, as people arrive and clear passport control, overlapping multiple activities and allowing tighter turnaround. Why should the gate close 40 minutes before take off? If a passenger just checked in, and it takes 10 minutes for the pod to get to the plane, that's the minimal effective cutoff (with a larger official cutoff for safety).
As for passport and baggage control, those can be automated and sped up to a large degree using new technologies. And of course, the will of people in charge to change anything - I've spent to many hours waiting long queues while only 30% of the desks were manned, to know they just don't see queues as a problem. As for the duty free revenue this whole circus brings in, it must be massive.
The whole duty free forced march -> endless tread mills -> gate -> bus routine is harrowing busy work. It creates multiple choke and synchronization points, thus multiple queues: you queue to enter the gate, than wait for everybody to board the bus, then queue again as people take their seats and place the luggage in the overheads.
It's a telling sign of how bad the current system is, when boarding on a single front door is considered a large speed up. A pod can take you to the right door in real time, gradually, as people arrive and clear passport control, overlapping multiple activities and allowing tighter turnaround. Why should the gate close 40 minutes before take off? If a passenger just checked in, and it takes 10 minutes for the pod to get to the plane, that's the minimal effective cutoff (with a larger official cutoff for safety).
As for passport and baggage control, those can be automated and sped up to a large degree using new technologies. And of course, the will of people in charge to change anything - I've spent to many hours waiting long queues while only 30% of the desks were manned, to know they just don't see queues as a problem. As for the duty free revenue this whole circus brings in, it must be massive.
> The whole duty free forced march -> endless tread mills
> -> gate -> bus routine is harrowing busy work.
Sorry, I do not really see how self-driving helps here, looks like a solution in search of a problem. Technology already changed a lot of things (self checkins, etc.) but it did not make flying a bit more enjoyable.
I disagree that the spatial layout of an airport is, even theoretically, designed to distribute the flow of passengers in time - otherwise, it wouldn't involve multiple queue/sync points, some involving all passengers of a flight.
It's a historic design from the age of grass strips, that sprawled as modern airports grew to handle more and more passengers, increasing the walking and waiting required from one point to another to the current, extreme situation. We now have buses taking you to the plane, airport monorails taking you to the terminal (Frankfurt) [1], and even pods moving you around the airport (Heathrow). [2]
Self driving pods are the obvious response to unify all these transport needs in a single end-to-end system that can spread the passenger load in time and massively simplify the airport construction.
[1] https://www.frankfurt-airport.com/en/travel/transfer.detail....
[2] https://en.wikipedia.org/wiki/ULTra_(rapid_transit)
It's a historic design from the age of grass strips, that sprawled as modern airports grew to handle more and more passengers, increasing the walking and waiting required from one point to another to the current, extreme situation. We now have buses taking you to the plane, airport monorails taking you to the terminal (Frankfurt) [1], and even pods moving you around the airport (Heathrow). [2]
Self driving pods are the obvious response to unify all these transport needs in a single end-to-end system that can spread the passenger load in time and massively simplify the airport construction.
[1] https://www.frankfurt-airport.com/en/travel/transfer.detail....
[2] https://en.wikipedia.org/wiki/ULTra_(rapid_transit)
Pods are just another form of queue...with their own sync points. Except now you've made the system brittle by making it dependent on a specific configuration of processes. Great when everything works...but far, far worse if any part of it breaks down.
The disembarkment from the cars to the tarmac should be almost instantaneous, and there is plenty of room there to queue if passengers are arriving faster then they can take their seats in the plane (a rare occurrence, absent other upstream sync points). There should be no traffic congestion and choke points in a properly designed airport because there is an enormous amount of horizontal space.
Failures due to very specific processes are a typical situation now - I recently waited about 20 minutes when the transfer bus would no longer start, then wasted another 15-20 minutes because the replacement bus took us to the arrivals section of another terminal - while we needed to connect to another flight on the same terminal. Had to go through baggage control again, passports, had to wait for the Frankfurt monorail mentioned above, almost lost the connecting flight.
Seems to me a flexible fleet could improve this situation enormously with awareness of the passenger circumstances - even to the point of taking you straight to your connecting plane without visiting the terminal. Failure should be isolated to the affected passengers, short of catastrophic events where there is no routearound.
Failures due to very specific processes are a typical situation now - I recently waited about 20 minutes when the transfer bus would no longer start, then wasted another 15-20 minutes because the replacement bus took us to the arrivals section of another terminal - while we needed to connect to another flight on the same terminal. Had to go through baggage control again, passports, had to wait for the Frankfurt monorail mentioned above, almost lost the connecting flight.
Seems to me a flexible fleet could improve this situation enormously with awareness of the passenger circumstances - even to the point of taking you straight to your connecting plane without visiting the terminal. Failure should be isolated to the affected passengers, short of catastrophic events where there is no routearound.
Yeah, in today's world, I can only imagine supersonic being of even any benefit on flights longer than 8 hours.
This reminds me of a Wendover video I've seen. The author discovers that airplanes used to fly much faster in the 1960s than they do today. So our flight times have actually gone up! He then explains the reasons behind it.
https://www.youtube.com/watch?v=n1QEj09Pe6k
https://www.youtube.com/watch?v=n1QEj09Pe6k
There is also another Wendover one explaining the economics or airlines classes and it talks about specifically why supersonic flights went into oblivion: https://www.youtube.com/watch?v=BzB5xtGGsTc
>Is killing the boom the key to supersonic air travel?
No. Cost is
No. Cost is
To get to low cost you need a lot of routes to fly on. Without a sonic boom can fly over land which opens up more routes. Therefore, the lack of a sonic boom does contribute to the comeback of supersonic air travel.
Sonic boom is a joke of a criterion. US is surely a big market, but nowhere as important as it was 40 years ago. US will have a choice: to deny SSTs when the rest of the world flies them, or do not do so.
But, cost above everything. You can't get economies of scale for an SST with even less than double the cost of regular business class.
But, cost above everything. You can't get economies of scale for an SST with even less than double the cost of regular business class.
I have no reason to think that the US would uniquely ban the use of technology that Western Europe was fine with. (Though one can certainly imagine e.g. China allowing for noise levels that the US and other countries wouldn't be OK with.)
Cost is really the thing though. Produce a modestly-sized supersonic jet that can do trans-Atlantic and equivalent routes that are profitable with business class-priced seats and you probably have a market.
Probably. A lot of business class seats today are filled with upgrades and I believe BA has actually cut back on the business-class only routes between NY and LCY.
Cost is really the thing though. Produce a modestly-sized supersonic jet that can do trans-Atlantic and equivalent routes that are profitable with business class-priced seats and you probably have a market.
Probably. A lot of business class seats today are filled with upgrades and I believe BA has actually cut back on the business-class only routes between NY and LCY.
You have to make it as cheap as cheap business class to get needed occupancy, AND have as many seats as smallest widebodies. And when you have it, you will have to fly ~7-10 years at loss till you get efficiencies of scale.
In other words, it is not happening.
In other words, it is not happening.
US will have a choice: to deny SSTs when the rest of the world flies them, or do not do so.
Totally okay with that. The rest of the world can pay for vastly increased maintenance costs in neighborhoods around SST airports for the benefit of the rich few who can actually afford to fly on those planes.
Totally okay with that. The rest of the world can pay for vastly increased maintenance costs in neighborhoods around SST airports for the benefit of the rich few who can actually afford to fly on those planes.
Which countries contain residents that are happy to have their windows broken by sonic booms several times a day? If one exists, then yes, they will be ahead of the curve on SST.
I suspect that the solution to the problem may look very different to the planes and drawings of planes shown in the article.
I know nothing of aerodynamics but what I do know is that innovation in aerodynamics is more likely to come from the world of F1 than the bowels of Lockheed Martin these days. This has actually been the case since the 'Gurney Flap' that was the first innovation in aero to come from motor racing to make its way to regular aerospace.
In 2017 at the Singapore Grand Prix the Force India F1 team surprised the fans with a new gadget to get extra downforce. In 2017 F1 cars had a 'sharkfin' engine cover and on top of this Force India had what looked like a hedge trimmer, this was 30 or so very small wings that worked together to create two powerful vortexes with the mini-winglets reinforcing the same vortex created by the mini-winglets at the front of this 'hedge trimmer' arrangement. From this they were able to get good downforce from an area of the engine cover/sharkfin that was not supposed to be downforce creating. The innovation obviously had to be banned and this is no longer a feature in 2018 cars.
F1 max speeds are lower than a plane and the aero is not about getting airborne, however, due to the rules there is constant innovation. Regular planes look as aerodynamically sophisticated as F1 cars from the 1980's. I suspect that to do supersonic without the boom then aerospace will have to borrow more than just the Gurney Flap from F1. Furthermore, incentives have to be better than pork barrel politics or else the Lockheed Martins of this world will be on this gravy train forever.
I know nothing of aerodynamics but what I do know is that innovation in aerodynamics is more likely to come from the world of F1 than the bowels of Lockheed Martin these days. This has actually been the case since the 'Gurney Flap' that was the first innovation in aero to come from motor racing to make its way to regular aerospace.
In 2017 at the Singapore Grand Prix the Force India F1 team surprised the fans with a new gadget to get extra downforce. In 2017 F1 cars had a 'sharkfin' engine cover and on top of this Force India had what looked like a hedge trimmer, this was 30 or so very small wings that worked together to create two powerful vortexes with the mini-winglets reinforcing the same vortex created by the mini-winglets at the front of this 'hedge trimmer' arrangement. From this they were able to get good downforce from an area of the engine cover/sharkfin that was not supposed to be downforce creating. The innovation obviously had to be banned and this is no longer a feature in 2018 cars.
F1 max speeds are lower than a plane and the aero is not about getting airborne, however, due to the rules there is constant innovation. Regular planes look as aerodynamically sophisticated as F1 cars from the 1980's. I suspect that to do supersonic without the boom then aerospace will have to borrow more than just the Gurney Flap from F1. Furthermore, incentives have to be better than pork barrel politics or else the Lockheed Martins of this world will be on this gravy train forever.
The key point you're missing is that subsonic and supersonic flows are very different - in terms of fluid dynamics, supersonic planes are not just faster than subsonic planes. Commercial jets and F1 cars are optimised for subsonic flows. To handle supersonic flight, you need to do things which are strange and suboptimal for subsonic travel. This is partly why subsonic planes don't look like concorde.
That's not to say cars won't have an effect on the design. Two avenues I can think of in particular are:
1) Concorde's shape made it _extremely_ noisey upon take-off. That's subsonic travel, so other subsonic vehicles might provide design inspiration (even though in some cases going supersonic may mean the inspiration has to be ignored) 2) Projects like Bloodhound SSC might provide inspiration.
That's not to say cars won't have an effect on the design. Two avenues I can think of in particular are:
1) Concorde's shape made it _extremely_ noisey upon take-off. That's subsonic travel, so other subsonic vehicles might provide design inspiration (even though in some cases going supersonic may mean the inspiration has to be ignored) 2) Projects like Bloodhound SSC might provide inspiration.
I think I mentioned that F1 cars go a little bit slowly, however, the point I was making is that some thinking outside of the box is needed, from some area of engineering that is actually innovative. Innovation isn't just about funding, no amount of money sponged off the taxpayer and given to NASA and their greedy contractors will solve the problem. You need engineering talent and people who can bend the rules and do things that go beyond what can be learned from studying textbooks.
You did mention that "F1 cars go a little bit slowly". The difference is that speed is pretty much irrelevant. It's sub/trans/super-sonic that matters.
The title is a bit silly -- sonic booms weren't what killed the Concorde, it was cost -- but I'm glad to see the article goes into the need for fixing both problems.
True, though the inability to do transcontinental flights exacerbated this by effectively eliminating any hope of recovering development costs or achieving any other economies of scale.
Noise around airports was also a very contentious issue - low-bypass jet engines and, especially, the use of afterburners on the takeoff roll. This will become an issue again even if the sonic boom problem is solved. Smaller aircraft may be quieter, but they are unlikely to be welcome at airports that cater primarily to business jets, if they are any louder than those in use now - and the trend is towards quieter.
Noise around airports was also a very contentious issue - low-bypass jet engines and, especially, the use of afterburners on the takeoff roll. This will become an issue again even if the sonic boom problem is solved. Smaller aircraft may be quieter, but they are unlikely to be welcome at airports that cater primarily to business jets, if they are any louder than those in use now - and the trend is towards quieter.
Firstly, all the big commercial investment has gone into sub-sonic planes, so they've gotten much cheaper. So to just have the same cost-ratio as concorde between supersonic vs. Standard flight is a big ask today. Secondly, Concorde wasn't just expensive -it was uneconomical because they couldn't fill the plane at those prices. Concorde was built in an era before deregulation - flights are far more cost competitive today. Thirdly, removing the sonic boom seems to imply inefficient shapes for the aircraft in terms of fitting numbers of passengers in. So even if the engines were far more efficient, you still have the fuel efficiency per passenger to worry about. For example Boom Supersonic are planning a 55 passenger plane. That is laughable as a commercial proposition.
I'm certain that companies working on this have concrete expectations of the cost o f a flight per person and the expected demand, I would just love to know what those are.