Boeing's Sonic Cruiser revised to Mach 1.8 ?
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Never saying no to anything but I can't see it flying mach1+ over populated land, I would have guessed that it is pretty impossible to get rid of the Sonic boom.
Where maybe they are looking is at developing the technology to enable it to fly at M1.8 as economically as at M0.98. This is Concordes current main failing as it is very unefficient at low speed.
But with new aerodynamic technology and modern engines who knows what could be done in a few years time
Where maybe they are looking is at developing the technology to enable it to fly at M1.8 as economically as at M0.98. This is Concordes current main failing as it is very unefficient at low speed.
But with new aerodynamic technology and modern engines who knows what could be done in a few years time
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You can't change the laws of physics. Energy is proportional to velocity squared. Thus, to go to 1.8M, it will be a lot more expensive. Airframers might be able to build a 1.8M aircraft significantly more efficient than Concorde. However, it does not change the fact that the supersonic aircraft will be a lot more expensive to operate than any contemporary subsonic jets. 0.98M seems to be a good compromise. That is, the increase in speed has the potential to allow airlines to significantly increase productivity. Hence, it will more than make up for the additional fuel costs. This means airlines can offer slightly faster services at about the same cost. If a passenger can pay the same price and fly 15% faster, I think most will choose a faster flight. Without an increase in productivity, a 0.98M aircraft will not be economically viable. Boeing's business case, I believe, is strongly hinged on the pontential to drastically increase the productivity of each aircraft. That's why airlines are interested in the proposal. Airlines may want higher speed, but when they see all the numbers, almost everyone will come to the same conclusion that a 1.8M aircraft would not be cost attractive. Not a single all-premium service has proven to be successful, and I doubt a 1.8M aircraft would reverse this trend.
[ 09 December 2001: Message edited by: casual observer ]
[ 09 December 2001: Message edited by: casual observer ]
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Rather curious that this supersonic sonic cruiser has only been mentioned in the Telegraph. Not a word about this very major change in the sonic cruiser's flight regime in the Seattle Post-Intelligencer or in the US press that I can see. Anyone find any other report of this in the press?
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I heard some time ago that, just with the technology advances made from Concorde, it would be possible to make an aircraft with half the weight but the same payload. Or the same weight and twice the payload.
The argument about the amount of energy is fallacious and wrong. Just because something has four times the kinetic energy (from travelling twice the speed) doesn't mean it uses four times as much fuel. In fact, the wing design of airliners is part of what stops them going faster - not the amount of energy input required.
Fact is that airliners run using about the same fuel per pax per km as cars - well, at least, the same order of magnitude. Work it out. There's a very interesting part of the Boeing website on the environmental impact of airliners.
Arthur C. Clarke wrote an interesting book called "Profiles of the Future", in which he comments on the two failures of futurologists - failure of the nerve, and failure of imagination. Believe it or not, at one stage people thought that anybody travelling more than 15 mph in a train would suffocate. The fact that people already travelled faster than that on horseback seemed to escape their notice.
At risk of losing one of my favourite tricks, guess how heavy a Concorde is at max AUW?
Now guess again.
The max certified is about the same as that of a B767-300.
The argument about the amount of energy is fallacious and wrong. Just because something has four times the kinetic energy (from travelling twice the speed) doesn't mean it uses four times as much fuel. In fact, the wing design of airliners is part of what stops them going faster - not the amount of energy input required.
Fact is that airliners run using about the same fuel per pax per km as cars - well, at least, the same order of magnitude. Work it out. There's a very interesting part of the Boeing website on the environmental impact of airliners.
Arthur C. Clarke wrote an interesting book called "Profiles of the Future", in which he comments on the two failures of futurologists - failure of the nerve, and failure of imagination. Believe it or not, at one stage people thought that anybody travelling more than 15 mph in a train would suffocate. The fact that people already travelled faster than that on horseback seemed to escape their notice.
At risk of losing one of my favourite tricks, guess how heavy a Concorde is at max AUW?
Now guess again.
The max certified is about the same as that of a B767-300.
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When you compare air travel will automobile travel, you are not comparing apples with apples. There are two flaws in your comparison:
1. What kind of friction force you have to overcome on roads and in the air? Are they of the similar magnitude? I think not.
2. You are comparing mass transport with personal transport. Do you think fuel consumption per passenger per unit distance of a bus is similar to that of a car? I think not.
[ 10 December 2001: Message edited by: casual observer ]
1. What kind of friction force you have to overcome on roads and in the air? Are they of the similar magnitude? I think not.
2. You are comparing mass transport with personal transport. Do you think fuel consumption per passenger per unit distance of a bus is similar to that of a car? I think not.
[ 10 December 2001: Message edited by: casual observer ]
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Boeing (or anyone else for that matter) will not build va successor to Concorde while Concorde is still flying, I suspect. It's all to do with economics.
The most profitable routes for a supersonic airliners, given that nobody wants then flying over land supersonically, are (1) Europe - East Coast States and (2) West Coast States to Japan, with the former being much more profitable than the latter.
The Europe - East Coast route is a money spinner for BA. They have that route sown up, much better than Air France does.
Any aircraft manufacturer would need to spend billions to develop and build a rival to Concorde. Those costs would be passed on to the customers (the airlines) who eventually bought such a machine. The airlines, in turn, would need to pass on those initial purchase costs to their passengers in the form of expensive tickets.
While Concorde is still flying, BA would be able to undercut any fare that any other airline flying a new supersonic aircraft would have to charge, as the BA's Concordes are already bought and paid for and have a much lower cost than any successor would have.
Therefore, whilst Concorde is still flying LHR-JFK and making the profit it does, no new supersonic aircraft will be built, I suspect, due to simple economics.
And as Concorde is planned to fly for another 7 - 10 years, I think we will have to wait a long time for another supersonic passenger aircraft to come into airline service.
Just my view, you understand.
The most profitable routes for a supersonic airliners, given that nobody wants then flying over land supersonically, are (1) Europe - East Coast States and (2) West Coast States to Japan, with the former being much more profitable than the latter.
The Europe - East Coast route is a money spinner for BA. They have that route sown up, much better than Air France does.
Any aircraft manufacturer would need to spend billions to develop and build a rival to Concorde. Those costs would be passed on to the customers (the airlines) who eventually bought such a machine. The airlines, in turn, would need to pass on those initial purchase costs to their passengers in the form of expensive tickets.
While Concorde is still flying, BA would be able to undercut any fare that any other airline flying a new supersonic aircraft would have to charge, as the BA's Concordes are already bought and paid for and have a much lower cost than any successor would have.
Therefore, whilst Concorde is still flying LHR-JFK and making the profit it does, no new supersonic aircraft will be built, I suspect, due to simple economics.
And as Concorde is planned to fly for another 7 - 10 years, I think we will have to wait a long time for another supersonic passenger aircraft to come into airline service.
Just my view, you understand.
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Casual observer,
Indeed you can't change the law of physics. As you could have seen in my rather generic graph the Drag coefficient increases to about a threefold between Mach .84 and M .98 together with an increase of TAS of about 15% this increases the Drag by a factor 4.
Now if you increase your speed again to M 1.8 your Cd decreases by a factor of three. It actually drops back to around the value it was at M .84. Now that the TAS increases by 80% you have a Drag increase of only about 10%.
On top of that you can do interesting tricks with the intake of a supersonic aircraft to improve fuel efficiency that you can't do while flying subsonic.
That is a law of the complex world of physics of transonic and supersonic flight. This made me wonder from the very beginning why Mr Boeing boldly went were no man has gone before .... so far.
Sq
Indeed you can't change the law of physics. As you could have seen in my rather generic graph the Drag coefficient increases to about a threefold between Mach .84 and M .98 together with an increase of TAS of about 15% this increases the Drag by a factor 4.
Now if you increase your speed again to M 1.8 your Cd decreases by a factor of three. It actually drops back to around the value it was at M .84. Now that the TAS increases by 80% you have a Drag increase of only about 10%.
On top of that you can do interesting tricks with the intake of a supersonic aircraft to improve fuel efficiency that you can't do while flying subsonic.
That is a law of the complex world of physics of transonic and supersonic flight. This made me wonder from the very beginning why Mr Boeing boldly went were no man has gone before .... so far.
Sq
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Captain Squelch:
If I am not mistaken, the graph you had previously doesn't include everything. If it does, why do you think the Concorde at 2.2M would burn so much fuel than the B707 at over .85M which was designed before the Concorde and had more drag than the Concorde, as your graph clearly depicted? Your graph certainly does not explain this fact, right? I certainly don't think the British and French engineers took a step backward then. Neither do I think the laws of physics have changed since then. Right?
[ 10 December 2001: Message edited by: casual observer ]
If I am not mistaken, the graph you had previously doesn't include everything. If it does, why do you think the Concorde at 2.2M would burn so much fuel than the B707 at over .85M which was designed before the Concorde and had more drag than the Concorde, as your graph clearly depicted? Your graph certainly does not explain this fact, right? I certainly don't think the British and French engineers took a step backward then. Neither do I think the laws of physics have changed since then. Right?
[ 10 December 2001: Message edited by: casual observer ]
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We have the usual dumb post from 411A - denegrating the technology of an aeroplane that is no older than the L1011 which he seems to love so much.
On more intelligent matters, when you look at the drag curve 0.98M never made sense - so why did the Boeing guys not see that before? Surely someone there must have done an Aerospace engineering degree? Whether the aeroplane will ever be cost effective enough to buy and operate is another matter - only Boeing will be able to decide that. However, I do feel that it will be good for the industry to have a successor to Concorde - even if it does come from the wrong side of the Atlantic. Thelead time will be such that Concorde will be on the way out as the (Super) Sonic Cruiser comes in.
Modern computer modelling will help to reduce the effect of booms - but I still doubt that it will be allow to drop booms over land. US government subsidies (sorry - NASA Research!) will ensure that whatever engine is required will be available, too.
However, will there be enough trade to see it sell? There will have to be more than just the North Atlantic and unless it can do West Coast USA to Japan non-stop it will lose it's advantage over convential craft.
Interesting times ahead for Boeing - I hope for their sake they have it right this time (unlike 747X and 757-300).
On more intelligent matters, when you look at the drag curve 0.98M never made sense - so why did the Boeing guys not see that before? Surely someone there must have done an Aerospace engineering degree? Whether the aeroplane will ever be cost effective enough to buy and operate is another matter - only Boeing will be able to decide that. However, I do feel that it will be good for the industry to have a successor to Concorde - even if it does come from the wrong side of the Atlantic. Thelead time will be such that Concorde will be on the way out as the (Super) Sonic Cruiser comes in.
Modern computer modelling will help to reduce the effect of booms - but I still doubt that it will be allow to drop booms over land. US government subsidies (sorry - NASA Research!) will ensure that whatever engine is required will be available, too.
However, will there be enough trade to see it sell? There will have to be more than just the North Atlantic and unless it can do West Coast USA to Japan non-stop it will lose it's advantage over convential craft.
Interesting times ahead for Boeing - I hope for their sake they have it right this time (unlike 747X and 757-300).
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There's been a lot of general misinformation on this (and other) supersonic threads. It is interesting to look at current research into eliminating sonic booms, with the intent of over land supersonic travel.
A sonic boom is a pressure wave, much like sound, and it is measured in the same way, as a change in pressure. Like sound, it is attenuated by distance, which in short hand means the further away you are, the quieter it is. No surprises so far.
There are two ways to increase the distance between the aircraft and the observer. The obvious way is to fly higher; the less obvious way is to fly faster. The shock wave has an angle which depends upon the speed; at higher speeds the shock wave angles further back, it extends much further before it hits the ground, hence a quieter shock wave.
Another way is to reduce the intensity of the source shock wave. Clever computers, aircraft profile and even microwaves to heat the air (hotter air = higher local speed of sound = less energy in the shock) have all been looked at.
Technology today probably allows a small aircraft to fly supersonically over land without anyone noticing. The SR-71 replacement (Aurora) almost certainly is a flying embodiment of this technology. Whether it is applicable to Concorde Mark II is harder to say. The speed required to angle the shock wave enough may be excessive - anything greater than M2.2 needs higher temperature metals than aluminium (this is the reason for this design point in Concorde and many military aircraft), which means further expense.
Maybe we have to wait until materials technology allows speeds of M3 to M5 at altiutudes of ~100k. This profile, even today, means no shock wave will reach the ground.
Engine technology - another major hurdle. I'll leave this for someone else.
[ 10 December 2001: Message edited by: Chris ]
A sonic boom is a pressure wave, much like sound, and it is measured in the same way, as a change in pressure. Like sound, it is attenuated by distance, which in short hand means the further away you are, the quieter it is. No surprises so far.
There are two ways to increase the distance between the aircraft and the observer. The obvious way is to fly higher; the less obvious way is to fly faster. The shock wave has an angle which depends upon the speed; at higher speeds the shock wave angles further back, it extends much further before it hits the ground, hence a quieter shock wave.
Another way is to reduce the intensity of the source shock wave. Clever computers, aircraft profile and even microwaves to heat the air (hotter air = higher local speed of sound = less energy in the shock) have all been looked at.
Technology today probably allows a small aircraft to fly supersonically over land without anyone noticing. The SR-71 replacement (Aurora) almost certainly is a flying embodiment of this technology. Whether it is applicable to Concorde Mark II is harder to say. The speed required to angle the shock wave enough may be excessive - anything greater than M2.2 needs higher temperature metals than aluminium (this is the reason for this design point in Concorde and many military aircraft), which means further expense.
Maybe we have to wait until materials technology allows speeds of M3 to M5 at altiutudes of ~100k. This profile, even today, means no shock wave will reach the ground.
Engine technology - another major hurdle. I'll leave this for someone else.
[ 10 December 2001: Message edited by: Chris ]
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There are various reasons why supersonic transport is not widespread. Environmental impact is one. Lack of demand is the other. However, if the demand were there, it could be done these days. Concorde runs at an operating profit, remember - in other words, it covers its costs. And this is old technology - we could do at least twice as well as that, these days - in other words, halve the cost of supersonic travel. You'd need to add a lump to the fare to cover development costs - and it's the size of that lump spread over a small market that has prevented development up to now. The argument about kinetic energy is nonsense, however. Of course, you need to convert potential energy (fuel) into kinetic energy to accelerate the aircraft. But that's what engines are for. If you can get things into space (escape velocity 12 km/s [?]), then Mach 1.8 is hardly a huge mountain, relatively.
And yes, on a longish flight, in a nearly full aircraft, the specific fuel burn (kg fuel per pax per km) is not far removed from that of a car. Aircraft do go faster (more drag) - but they are in thinner air, and experience less resistance from air than cars do from roads. Also they travel in a straightish line, and cars generally don't. And their engines are **substantially** more efficient than car petrol engines.
And yes, on a longish flight, in a nearly full aircraft, the specific fuel burn (kg fuel per pax per km) is not far removed from that of a car. Aircraft do go faster (more drag) - but they are in thinner air, and experience less resistance from air than cars do from roads. Also they travel in a straightish line, and cars generally don't. And their engines are **substantially** more efficient than car petrol engines.
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Exile from Groggs:
It is exactly my point that you have less resistant in the air than on road surfaces, that's why we can make air travel affordable.
However, we are talking about different aircraft flying at different speeds. Even though they will be flying at different altitudes (thus, different air resistance) and different speeds (thus, different drag), the differences are not big enough to make flying at 1.8M cost about the same as flying at .85M. We sure have the technology to fly faster. There are plenty of experimental and military aircraft that have achieved speeds much higher than Concorde's 2.2M. However, we don't have the technology to make it affordable. Airlines cannot (profitably) create demand at will. Until we have the technology to make supersonic travel affordable to the general public, not just some elite groups, no supersonic jets will be mass produced.
Airlines can ask Boeing to study a 1.8M aircraft. Nevertheless, when the numbers come out, all sensible airlines will see it will not be an economically viable aircraft, at least not in the near future.
It is exactly my point that you have less resistant in the air than on road surfaces, that's why we can make air travel affordable.
However, we are talking about different aircraft flying at different speeds. Even though they will be flying at different altitudes (thus, different air resistance) and different speeds (thus, different drag), the differences are not big enough to make flying at 1.8M cost about the same as flying at .85M. We sure have the technology to fly faster. There are plenty of experimental and military aircraft that have achieved speeds much higher than Concorde's 2.2M. However, we don't have the technology to make it affordable. Airlines cannot (profitably) create demand at will. Until we have the technology to make supersonic travel affordable to the general public, not just some elite groups, no supersonic jets will be mass produced.
Airlines can ask Boeing to study a 1.8M aircraft. Nevertheless, when the numbers come out, all sensible airlines will see it will not be an economically viable aircraft, at least not in the near future.
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It's the general consensus that if you want to go faster, you need to go higher.
If you go higher, there's no air, so you can't use jets. Also as there is no air, there's no sonic boom (can anyone hear the Shuttle?).
The key is the engine technology. You need a Scramjet engine - one that can operate as a jet and then progressively turn into a rocket as you change the flight regime.
Ironically, Rolls Royce designed such an engine for the HOTOL - the RB 545? - 'Swallow' I think it was called. However, canning it 'in the interests of national security' was _such_ a good idea.....
If you go higher, there's no air, so you can't use jets. Also as there is no air, there's no sonic boom (can anyone hear the Shuttle?).
The key is the engine technology. You need a Scramjet engine - one that can operate as a jet and then progressively turn into a rocket as you change the flight regime.
Ironically, Rolls Royce designed such an engine for the HOTOL - the RB 545? - 'Swallow' I think it was called. However, canning it 'in the interests of national security' was _such_ a good idea.....
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Could you operate a SST with a fuel burn about 20-25% higher than a sub-sonic? Could you shift 150 or so airframes to cover development costs? (Or alternatively, tap into an appropriately targeted NASA program, as US mfrs tend to).
Is there a market? Suppose you designed one hull, with several fuel and fitting options. One could carry 240 economy pax for 3-4 hours, at a premium of (say) 30% - Say W. Europe - E.USA. Bear in mind that there is already a market for an upgraded economy product, with more legroom. What about halving journey time? No need to travel W-E overnight!
Then another option would carry 120 premium pax up to 7-8 hours - say US-Japan or China, UK-SA, Germany-Sao Paolo. A third would sew up the first class long-haul market by carrying 30 or so first class pax around the world direct in 10-12 hours - no refuelling stops; no ATC delays or tangling with weather; arrive feeling fresh (if jet-lagged!).
OK, slightly fanciful - particularly the last one. Also lots of pilots needed, due to radiation counts. But you have to think "marketing". Someone can make you want these things!
Is there a market? Suppose you designed one hull, with several fuel and fitting options. One could carry 240 economy pax for 3-4 hours, at a premium of (say) 30% - Say W. Europe - E.USA. Bear in mind that there is already a market for an upgraded economy product, with more legroom. What about halving journey time? No need to travel W-E overnight!
Then another option would carry 120 premium pax up to 7-8 hours - say US-Japan or China, UK-SA, Germany-Sao Paolo. A third would sew up the first class long-haul market by carrying 30 or so first class pax around the world direct in 10-12 hours - no refuelling stops; no ATC delays or tangling with weather; arrive feeling fresh (if jet-lagged!).
OK, slightly fanciful - particularly the last one. Also lots of pilots needed, due to radiation counts. But you have to think "marketing". Someone can make you want these things!
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The fact remains taht there is not the demand for a large fleet of supersonic a/c. Although everybody wants to get to the destination more quickly, most people are not willing to pay. Although some Concorde pax will claim that it makes them more effective, Concorde is basically marketed for its unique capabilities, being the only a/c in which ordinary pax can go supersonic. There has never been enough demand to utilise all Concordes on the trans-atlantic route (trans-pacific not possible and no other route found to be profitable), many were used for charter services. There were reports several years ago of a US business jet manufacturer (Gulfsteam??) teaming up with a Russian design bureau (Tupolev??) to produce a supersonic BJ, but nothing appears to have happened with this project
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Could you operate a SST with a fuel burn about 20-25% higher than a sub-sonic?
Could you shift 150 or so airframes to cover development costs?
(Or alternatively, tap into an appropriately targeted NASA program, as US mfrs tend to).
Is there a market? Suppose you designed one hull, with several fuel and fitting options. One could carry 240 economy pax for 3-4 hours, at a premium of (say) 30% - Say W. Europe - E.USA. Bear in mind that there is already a market for an upgraded economy product, with more legroom. What about halving journey time? No need to travel W-E overnight!
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Until Boeing releases what altitude and engine type they plan to use, it seems that we dont know enough to determine if their SST aircraft makes sense or not. . Again I ask, is there any country that allows the Concorde to fly over a populated area. I wonder especially about England.................
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Polzin - yes Concorde may fly over populated areas, but only subsonic. That is why it is actually allowed to get airborne and land again! However, they head off over the southwest of England to reach the Altlantic without having to dealy supersonic flight due to crossing Ireland. These routes also keep them clear of the other North Atlantic tracks so that you don't drop a boom on someone's 747!
Incidentally, as a military transport pilot I have flown underneath Concorde on these southern routes and you can feel and hear the double boom as it passes 30,000' above you.
Mycroft - the Gulfstream tie-up was with Sukhoi who are currently producing some great airframes but there is no sign of the proposed SSBJ yet.
Incidentally, as a military transport pilot I have flown underneath Concorde on these southern routes and you can feel and hear the double boom as it passes 30,000' above you.
Mycroft - the Gulfstream tie-up was with Sukhoi who are currently producing some great airframes but there is no sign of the proposed SSBJ yet.