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A New Engine Could Bring Back Supersonic Air-Travel (economist.com)
An anonymous reader shares a report (may be paywalled): Every morning, time once was, a giant roar from Heathrow Airport would announce the departure of flight BA001 to New York. The roar was caused by the injection into the aircraft's four afterburners of the fuel which provided the extra thrust that it needed to take off. Soon afterwards, the pilot lit the afterburners again -- this time to accelerate his charge beyond the speed of sound for the three-and-a-half hour trip to JFK. The plane was Concorde.
Supersonic passenger travel came to an end in 2003. The crash three years earlier of a French Concorde had not helped, but the main reasons were wider. One was the aircraft's Rolls-Royce/Snecma Olympus engines, afterburners and all, which gobbled up too much fuel for its flights to be paying propositions. The second was the boom-causing shock wave it generated when travelling supersonically. That meant the overland sections of its route had to be flown below Mach 1. For the Olympus, an engine optimised for travel far beyond the sound barrier, this was commercial death.
That, however, was then. And this is now. Materials are lighter and stronger. Aerodynamics and the physics of sonic booms are better understood. There is also a more realistic appreciation of the market. As a result, several groups of aircraft engineers are dipping their toes back into the supersonic pool. Some see potential for planes with about half Concorde's 100-seat capacity. Others plan to start even smaller, with business jets that carry around a dozen passengers. The chances of such aircraft getting airborne have recently increased substantially.
Supersonic passenger travel came to an end in 2003. The crash three years earlier of a French Concorde had not helped, but the main reasons were wider. One was the aircraft's Rolls-Royce/Snecma Olympus engines, afterburners and all, which gobbled up too much fuel for its flights to be paying propositions. The second was the boom-causing shock wave it generated when travelling supersonically. That meant the overland sections of its route had to be flown below Mach 1. For the Olympus, an engine optimised for travel far beyond the sound barrier, this was commercial death.
That, however, was then. And this is now. Materials are lighter and stronger. Aerodynamics and the physics of sonic booms are better understood. There is also a more realistic appreciation of the market. As a result, several groups of aircraft engineers are dipping their toes back into the supersonic pool. Some see potential for planes with about half Concorde's 100-seat capacity. Others plan to start even smaller, with business jets that carry around a dozen passengers. The chances of such aircraft getting airborne have recently increased substantially.
F-22 has engines that provide so much efficient thrust, it can cruise at supersonic speeds without using the afterburner.
So you just need to scale up the F-22 to carry 100 people!
I love progress. A plane that can go past the speed of sound and only half the number of seats of Concord? Sounds like a great plan.
30 minutes to any city on earth sounds pretty good, and I am pretty sure SpaceX will be getting at least one such commercial flight out in the next five years or so... they also can carry 100 people at a time, and passengers get a free sub-space visual to boot.
Even supersonic would look pokey next to that.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
tower this is ghostrider requesting a flyby
>> I am pretty sure [thing promised by company will happen] in the next five years No wonder companies continue advertise here: Slashdot remains a target-rich environment filled with consumers who are easily persuaded by flimsy promises. Why don't we go ahead an speculate on which flying cars we'll have in five years while we're at it?
I dunno, every time people say that Musk can't do something, he says "hold my bong" ...
Slashdot remains a target-rich environment filled with consumers who are easily persuaded by flimsy promises
What is flimsy about such a prediction? The BFR is flying just next year. It's not hard to see them putting up at least one commercial flight within the next five as a test of viability, after all it has a huge attraction for flights like NYC to Australia which otherwise take a very long time. Tickets would sell like hotcakes.
Why don't we go ahead an speculate on which flying cars we'll have in five years while we're at it?
That's actually about five to ten years out, made possible by self driving car tech. it was never going to happen when humans were the ones flying the car, which is why we've never really see that come about even tough every now and then you read about flying car designs. Just like self driving cars, the first applications will be taxis more than personal transport, though that too will come.
What never ceases to amaze me about Slashdot is that people used to technology, can be such negative luddites despite years and years of being shown technology can make amazing advances quickly when conditions are right.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
It really isn't that far of stretch...
Imagine Just Read the Instructions being manufactured and deployed en masse. You have landing zones essentially anywhere there is water - Lake Erie for Buffalo, Back Bay for Boston (ha! jk, I mean near Logan), Upper Bay for NYC, Biscayne Bay for Miami, etc etc all over the world.
That's anywhere, with sea access, in the world in 30 minutes.
Flight, from launch to landing, is already 100% automated / controlled from ground.
Drag is really bad from just about Mach 0.8 to about 1.8 or so. That doesn't have anything to do with the engines or anything else you can control. It's a constant known as cD that isn't largely independent of aircraft design.
Meaning you need to cruise at about Mach 2 to have reasonable efficiency in terms of drag.
Supersonic flight isn't just "subsonic flight, but faster". The design of a high speed aircraft is all about how the air flows around the aircraft and through the engines. At Mach 1, which is kinda like "the maximum speed of air", that totally changes. Things work completely differently.
So you have to design your engine for Mach 2, your airframe, etc. All of these will be designed very differently than they would be for subsonic flight. Especially if you intend to fly over land, you're going to need to fly subsonic a significant portion of the time (plus you need to take off and land, and you're not landing at supersonic speeds).
So you have a problem. You need a plane designed to work very well at Mach 2, and it has to be designed to work well subsonic. These are two very different designs. It's hard to have the same plane do well with both. It's kinda like designing an ocean-going ship that's also a bicycle.
TFS does list a handful of the issues with commercial supersonic flight, and I do think that there may be room for those smaller planes. However, supersonic flights have increased competition...
1.) "The cost of three hours". NY to Heathrow is a 7-8 hour flight using standard jets. NY to Heathrow at mach 1.4 is 3-4 hours. If the cost of a ticket is triple, then those three hours have to be worth thousands of dollars *and* there has to be a reason why "fly the day before and book a hotel" isn't practical.
2.) First Class. For the cost of a supersonic flight where every seat is basically a coach seat, passengers can get posh seats that go completely horizontal and get good food and entertainment. A better flight experience can make the 3 hour difference far more tolerable. Concorde didn't have that, and the cost of a first class seat on a supersonic flight would be so exorbitant that it could only be afforded by people who probably have their own private jet anyway.
3.) Telecommuting. Some things still need to be done in person, but Zoom and WebEx have made it possible to have multi-continent, real-time teleconferences. A meeting that would cost a company tens of thousands of dollars to arrange to get everyone in the same room in such a tight timetable that a three hour difference is worth the cost *might* happen once or twice a year, but dozens of teleconferences in between make those cases exceptional at best.
4.) Fuel costs. It takes a LOT more fuel to run a plane at supersonic speeds. Even a small change in fuel costs will drastically impact per-passenger profitability for a flight that's as fuel hungry as supersonic. Yes, planes are lighter now, and yes, this is less of a deal on the smaller planes, but it's still a big deal to airlines, and the tightrope walk between "keeping it profitable" and "keeping the costs low enough to justify using this service over the other options" may very well mean that even a modest bump in fuel costs turns a 1% profit into a 1% deficit.
Commercial supersonic flight is very, very difficult to do profitably.
How many people old enough to afford it can stand the 9Gs necessary
3Gs, not 9.
With good chairs that doesn't seem like much of a stretch.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
30 years ago, the main appeal of Concorde (other than the snob value) was the fact that a senior business person was only out of contact with the office for a few hours. Fast forward to nearly-2019 and by the time a new supersonic passenger jet is in the air that advantage will mostly have gone away - With broadband connectivity over the Atlantic, a businessperson will no longer be out of touch from HQ. They can sit in their first class seat, work, make and take calls, send and receive emails, have a couple of glasses of wine and sleep in a lie-flat bed for the same price (or less) than a sardine-seat in a supersonic airliner. I suspect more and more that's where the market will go.
It depends on the price. If it's 1.5 or 2x the cost of a standard economy class ticket, yes it will do very well. If the price is 10 or 20X the cost of a first class seat on a standard airline, no,
Shortest flight from NYC to Sydney I could find was 20 hours. 20 hours vs 30 minutes... You care to revise that prediction at all?
"There is more worth loving than we have strength to love." - Brian Jay Stanley
London-NY subsonic: 7.5 hours
London-NY supersonic: 3.5 hours
Waiting at the check-in desk, checking in, waiting in line at the airport for the security theater, walking the airport's corridors, waiting at the gate, boarding, taxiing, landing, disembarking, walking some more, waiting at the baggage claim, etc: 3 hours if you're lucky. That's assuming flying supersonic isn't reserved for rich fucks who get to fast-track the whole process of course...
Conclusion: if you want people to travel faster, it would make more economic sense to reduce the time it takes *before* and *after* the flying proper.
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
So in trying to reduce CO2 emissions, that will be the major reason supersonic commercial air travel doesn't "take off".
If that were true they would not still be holding climate change conferences where 500 people fly in on 500 private jets.
Those are the same people that would be using the supersonic transport if it were available....
The only question you have to ask when considering if CO2 emissions will be a factor in something not being done is; would it inconvenience the ruling class?
"There is more worth loving than we have strength to love." - Brian Jay Stanley
Supersonic over the Pacific would still be a game changer. My last 17 hour flight to Singapore was way, way too long. Even in business it's just not fun.
If you could have this (Concorde) for 8 hours supersonic -
https://media3.ausbt.com.au/15...
Or this (Singapore Airlines) for 17 hours subsonic (for the same price) -
https://samchui.com/wp-content...
Which would you choose?
The whole problem with supersonic flight is that it's not efficient. The sonic boom and the aircraft heating up is a sign that you're pushing really hard against the fluid that is the atmosphere. If they can somehow magically eliminate the sonic boom and all the external heating from all that drag then you stand a chance to become more efficient. You need a whole lot more than epic engines to make this work. It's like slapping a truck engine into a small car and claiming that suddenly you can race in Formula 1.
Snob value ... like Apple crap ... is sufficient to justify anything.
Not really - If it was, the Concorde would still be flying.
There aren't enough snobs to make a service like Concorde profitable.
It doesn't really vary much at all with velocity per se (partly because the definition of Cd includes a division by V2 term).
Its pretty much constant from 1 kmh through the entire subsonic regime to over 1,000 kmh. Just below Mach 2 the Cd is right back to its subsonic value and remains constant at hypersonic velocities. It's onlyduring that transition from about Mach 1 to Mach 2 that the suddenly very different behavior of air flows makes it wonky for that particular range.
You are correct that V2 is a very important term, of course.
However, the V2 is divided by V to get the drag per distance, which is what matters for passenger flights. You're trying to get from point A to point B, not trying to fly for one hour. Therefore the V squared term ends up as just V.
This divisiin by V has some very interesting and counterintuitive implications for gliders.
I don't see why everybody else needs to give up their sleep just so the super rich can be somewhere a few hours early. For society as a whole, that is actually a really bad trade off.