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None of the engine manufacturers are interested. That's what killed the A380--Rolls Royce pulled out of a re-engine deal that would've brought A380 engines into

by wahern 4y ago

None of the engine manufacturers are interested. That's what killed the A380--Rolls Royce pulled out of a re-engine deal that would've brought A380 engines into the 21st century. "Green" concept showcases notwithstanding, all the engine manufactures seem to have decided to cut back on investment and coast for awhile. Something will need to change to spur competition in the engine space, and then we might see hungrier competitors. But the shelving of the A380 supply chain means there'll still be a steep hill to an A380 derivative.

MichaelZuo 4y ago
The latest and greatest engines are not that far from the theoretical thermodynamic efficiency limit. So future designs are running into the hard part of the asymptote. I doubt airlines are actually interested in committing tens of billions of capital, today, to get a dozen % improvement in fuel efficiency a decade from now. And why would a private investor take such a huge risk without guarantees of making it back several fold? So it doesn't happen.
- credit_guy 4y ago
  > The latest and greatest engines are not that far from the theoretical thermodynamic efficiency limit. So future designs are running into the hard part of the asymptote. No. Even if an engine got to the Carnot efficiency, you can still improve it. Massively. You can push a certain quantity of air with a velocity v or 4 times that quantity with half the velocity. The second option produces twice the thrust, for the same fuel consumption. That's the reason engines are getting larger and larger, and going for higher and higher bypass ratios. Separately, the maximum theoretical (Carnot) efficiency depends on how hot the engine runs. GE has introduced turbines made of silicon carbide, which can withstand absurdly high temperatures. Silicon carbide melts at more than 2800 Celsius, but they don't push it to such limits. But they push it to more than 1300 Celsius [1]. Military jet engines run much hotter though. Exact numbers are classified, but according to [2] the temperature inside F35's engine might reach 2000 Celsius (the actual number is obviously classified). Of course, military jet engines are many times more expensive than civilian ones, with higher maintenance costs, and lifespan about 2 orders of magnitude shorter. Still the fact that they can run this hot means improvements for the civilian jet engines are possible. And they will happen. [1] https://www.ornl.gov/news/ceramic-matrix-composites-take-flight-leap-jet-engine https://www.ornl.gov/news/ceramic-matrix-composites-take-fli... [2] https://www.researchgate.net/publication/285727346_Fahrenheit_3600 https://www.researchgate.net/publication/285727346_Fahrenhei...
- wahern 4y ago
  Sure, it's obviously a matter of diminishing returns and opportunity cost. But the re-engine for the A380 was basically a rote, low-risk, B-team exercise for Rolls Royce. All they had to do was tweak their existing generation stuff. The program was already well underway, and they still dropped it; they all but explicitly said the reason was, "meh, we lost interest". Something seems to have changed. Putting my cynical cap on, my hot take is this: Everybody now realizes that Emirates and Clark are exactly right. As was Airbus.[1] Demand will blow past supply (i.e. runways and gates). Ticket prices will sky rocket. But from the perspective of the plane and engine manufacturers this translates to, "if everybody sits on their hands and does nothing, we're going to enjoy a windfall of profits". Clearly, IMO, Boeing, all the engine manufacturers, and now (somewhat despite themselves) Airbus, are going to passively collude[2] to bring about this windfall. All they need to do is sit tight and wait things out. The threat of competition isn't significant enough to break the collusion; there are too few players, the barriers to entry--regulation, technical and logistical expertise, etc--too steep, and like with housing little prospect that political reforms will make it easier to build enough new runways and airports to change the capacity trajectory. Similar calculus applies to most of the established carriers. There's much more competition among them, but if the manufacturers are expected to continue to coast there's no angle to exploit in that regard and thus little incentive to agitate for disruption along this dimension, and so the carriers also get to look forward to windfall profits, notwithstanding that they'll be forking over much of it to the manufacturers. Clark just isn't cold-blooded enough to want to play that game; he's got too much of a fighting spirit. (Or perhaps more realistically it's also because if Emirates doesn't keep growing it won't be viable in this prospective future reality?) [1] Boeing wasn't wrong, either, but point-to-point only bought a couple of decades of supply expansion. [2] I think there's an economics term for this, but I don't remember it.
  - rippercushions 4y ago
    Boeing, Airbus, and Rolls-Royce are going to be in for a rude awakening if/when the Chinese aircraft industry ever gets their shit together, and/or if batteries ever become light/dense enough to support electric passenger flight. That said, watching the Comac C919 shitshow (14 years and still not in revenue service, and this is for a 737/A320 clone), I'm not holding my breath. The twin-aisle C929 is still a decade away at best, and it'll take a good long time until any Western airline trusts it; even Chinese turboprops (Xian MA-60/600/700) have so far only managed to find buyers in Africa and the poorer bits of Asia. https://en.wikipedia.org/wiki/Comac_C919 https://en.wikipedia.org/wiki/Comac_C919 https://en.wikipedia.org/wiki/CRAIC_CR929 https://en.wikipedia.org/wiki/CRAIC_CR929
- throwaway2037 4y ago
  not that far from the theoretical thermodynamic efficiency limit This is an interesting comment. It is not my field of expertise, but I am interested to learn more. Can you share more info or maybe a paper/blog? Thanks.
midoridensha 4y ago
Why do they need new engines? Would it be that hard to just use some new, existing engine (like whatever they put on the 787) and stick that on the A380? Or is it not feasible because 2 of them aren't enough for such a large plane, and 4 of them are just too much engine and don't yield enough fuel savings because they're being run at part-throttle? These planes might not make much sense for many routes, but for trans-Pacific routes and other very long-haul routes, a huge plane like this is great.
- wahern 4y ago
  The plane is too big for 2 engines. But the massive engines for 2-engined planes are too big and inefficient for use in a 4 engine configuration. For example, each engine on 2-engine plane must be powerful enough alone for takeoff, whereas in a 4-engine configuration safety regulations only require a minimum of 2 (or 3?) working engines. The former require a much larger performance envelope, even though that increased performance is only required for a brief moment if ever, which is a source of inefficiency. Similarly, maintenance requirements are stricter for the former as they require more frequent safety checks and because they're run harder during takeoff (to reduce the width of the performance profile) they break down more frequently. This is why a 4-engined plane like the A380 isn't necessarily less economical for having 4 engines instead of 2. Airbus and Emirates have always argued, and arguably Emirates has demonstrated, that all things considered the A380's 4 engine configuration is still cost competitive. However, long-term these factors cannot overcome the aged engine technology. When the A380 debuted, its engines were already half a generation behind the latest, greatest wide body engines, and now they're even further behind. Moreover, IIRC, even older 777 models have received engine upgrades so now the A380's engines are technologically behind aircraft that preceded it. Airbus and Emirates weren't asking Rolls Royce to deliver anything fancy; just a replacement engine sporting updated blade designs, increased bypass, and other ubiquitous advancements since the mid 1990s; but nothing bleeding edge, like new gearing technology. Rolls Royce agreed, but then decided to pull out because they were "scaling back" (IIRC), not because costs ballooned or any other aspect specific to the project changed.
  - throwaway2037 4y ago
sumedh 4y ago
> Something will need to change to spur competition in the engine space, Isn't SpaceX going to use Starship for international travel. That might motivate these engine makers.
- gambiting 4y ago
  That's an insane plan no matter how anyone looks at it.
  - sumedh 4y ago
    If you tell someone 100 years back that 100's of people will be flying in a metal cylinder with wings and engines(aka planes), they will think you are insane.

by wahern 4y ago

MichaelZuo 4y ago

The latest and greatest engines are not that far from the theoretical thermodynamic efficiency limit. So future designs are running into the hard part of the asymptote. I doubt airlines are actually interested in committing tens of billions of capital, today, to get a dozen % improvement in fuel efficiency a decade from now. And why would a private investor take such a huge risk without guarantees of making it back several fold? So it doesn't happen.

credit_guy 4y ago
> The latest and greatest engines are not that far from the theoretical thermodynamic efficiency limit. So future designs are running into the hard part of the asymptote. No. Even if an engine got to the Carnot efficiency, you can still improve it. Massively. You can push a certain quantity of air with a velocity v or 4 times that quantity with half the velocity. The second option produces twice the thrust, for the same fuel consumption. That's the reason engines are getting larger and larger, and going for higher and higher bypass ratios. Separately, the maximum theoretical (Carnot) efficiency depends on how hot the engine runs. GE has introduced turbines made of silicon carbide, which can withstand absurdly high temperatures. Silicon carbide melts at more than 2800 Celsius, but they don't push it to such limits. But they push it to more than 1300 Celsius [1]. Military jet engines run much hotter though. Exact numbers are classified, but according to [2] the temperature inside F35's engine might reach 2000 Celsius (the actual number is obviously classified). Of course, military jet engines are many times more expensive than civilian ones, with higher maintenance costs, and lifespan about 2 orders of magnitude shorter. Still the fact that they can run this hot means improvements for the civilian jet engines are possible. And they will happen. [1] https://www.ornl.gov/news/ceramic-matrix-composites-take-flight-leap-jet-engine https://www.ornl.gov/news/ceramic-matrix-composites-take-fli... [2] https://www.researchgate.net/publication/285727346_Fahrenheit_3600 https://www.researchgate.net/publication/285727346_Fahrenhei...
wahern 4y ago
Sure, it's obviously a matter of diminishing returns and opportunity cost. But the re-engine for the A380 was basically a rote, low-risk, B-team exercise for Rolls Royce. All they had to do was tweak their existing generation stuff. The program was already well underway, and they still dropped it; they all but explicitly said the reason was, "meh, we lost interest". Something seems to have changed. Putting my cynical cap on, my hot take is this: Everybody now realizes that Emirates and Clark are exactly right. As was Airbus.[1] Demand will blow past supply (i.e. runways and gates). Ticket prices will sky rocket. But from the perspective of the plane and engine manufacturers this translates to, "if everybody sits on their hands and does nothing, we're going to enjoy a windfall of profits". Clearly, IMO, Boeing, all the engine manufacturers, and now (somewhat despite themselves) Airbus, are going to passively collude[2] to bring about this windfall. All they need to do is sit tight and wait things out. The threat of competition isn't significant enough to break the collusion; there are too few players, the barriers to entry--regulation, technical and logistical expertise, etc--too steep, and like with housing little prospect that political reforms will make it easier to build enough new runways and airports to change the capacity trajectory. Similar calculus applies to most of the established carriers. There's much more competition among them, but if the manufacturers are expected to continue to coast there's no angle to exploit in that regard and thus little incentive to agitate for disruption along this dimension, and so the carriers also get to look forward to windfall profits, notwithstanding that they'll be forking over much of it to the manufacturers. Clark just isn't cold-blooded enough to want to play that game; he's got too much of a fighting spirit. (Or perhaps more realistically it's also because if Emirates doesn't keep growing it won't be viable in this prospective future reality?) [1] Boeing wasn't wrong, either, but point-to-point only bought a couple of decades of supply expansion. [2] I think there's an economics term for this, but I don't remember it.
- rippercushions 4y ago
  Boeing, Airbus, and Rolls-Royce are going to be in for a rude awakening if/when the Chinese aircraft industry ever gets their shit together, and/or if batteries ever become light/dense enough to support electric passenger flight. That said, watching the Comac C919 shitshow (14 years and still not in revenue service, and this is for a 737/A320 clone), I'm not holding my breath. The twin-aisle C929 is still a decade away at best, and it'll take a good long time until any Western airline trusts it; even Chinese turboprops (Xian MA-60/600/700) have so far only managed to find buyers in Africa and the poorer bits of Asia. https://en.wikipedia.org/wiki/Comac_C919 https://en.wikipedia.org/wiki/Comac_C919 https://en.wikipedia.org/wiki/CRAIC_CR929 https://en.wikipedia.org/wiki/CRAIC_CR929
throwaway2037 4y ago
not that far from the theoretical thermodynamic efficiency limit This is an interesting comment. It is not my field of expertise, but I am interested to learn more. Can you share more info or maybe a paper/blog? Thanks.

midoridensha 4y ago

Why do they need new engines? Would it be that hard to just use some new, existing engine (like whatever they put on the 787) and stick that on the A380? Or is it not feasible because 2 of them aren't enough for such a large plane, and 4 of them are just too much engine and don't yield enough fuel savings because they're being run at part-throttle? These planes might not make much sense for many routes, but for trans-Pacific routes and other very long-haul routes, a huge plane like this is great.

wahern 4y ago
The plane is too big for 2 engines. But the massive engines for 2-engined planes are too big and inefficient for use in a 4 engine configuration. For example, each engine on 2-engine plane must be powerful enough alone for takeoff, whereas in a 4-engine configuration safety regulations only require a minimum of 2 (or 3?) working engines. The former require a much larger performance envelope, even though that increased performance is only required for a brief moment if ever, which is a source of inefficiency. Similarly, maintenance requirements are stricter for the former as they require more frequent safety checks and because they're run harder during takeoff (to reduce the width of the performance profile) they break down more frequently. This is why a 4-engined plane like the A380 isn't necessarily less economical for having 4 engines instead of 2. Airbus and Emirates have always argued, and arguably Emirates has demonstrated, that all things considered the A380's 4 engine configuration is still cost competitive. However, long-term these factors cannot overcome the aged engine technology. When the A380 debuted, its engines were already half a generation behind the latest, greatest wide body engines, and now they're even further behind. Moreover, IIRC, even older 777 models have received engine upgrades so now the A380's engines are technologically behind aircraft that preceded it. Airbus and Emirates weren't asking Rolls Royce to deliver anything fancy; just a replacement engine sporting updated blade designs, increased bypass, and other ubiquitous advancements since the mid 1990s; but nothing bleeding edge, like new gearing technology. Rolls Royce agreed, but then decided to pull out because they were "scaling back" (IIRC), not because costs ballooned or any other aspect specific to the project changed.
- throwaway2037 4y ago

sumedh 4y ago

> Something will need to change to spur competition in the engine space, Isn't SpaceX going to use Starship for international travel. That might motivate these engine makers.

gambiting 4y ago
That's an insane plan no matter how anyone looks at it.
- sumedh 4y ago
  If you tell someone 100 years back that 100's of people will be flying in a metal cylinder with wings and engines(aka planes), they will think you are insane.