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This is why AICC bought the An-225. They don't just get the planes, they get the tooling and training to build their own, including the engines. And at this po

This is why AICC bought the An-225. They don't just get the planes, they get the tooling and training to build their own, including the engines. And at this point, even a multiple-generations-old high-bypass turbofan is a big jump for China's domestic industry. They are not "easy" or "simple" to make and understand once you get down to the metallurgy and the fabrication techniques for stuff like the fan and compressor blades.

southern_cross 8y ago
Designs for the basic jet engine date back to at least the 1920s, and basic operating principles date back much, much further. Jet aircraft were actually flying by the 1940s, and those engines were built using the relatively primitive metallurgical and manufacturing techniques of the day. So, as I said, _mechanically_ jet engines are relatively simple devices. Materials, manufacturing, control systems, fuel efficiency, noise abatement and all that may be a very different story.
- ubernostrum 8y ago
  I didn't say otherwise. Jet engines have always been held back not by their mechanical complexity (they're mechanically pretty simple, as you point out), but by the difficulty of obtaining/fabricating materials that can withstand the temperatures and pressures of operation at the desired weight. Reciprocating engines were far more complex mechanically, but lasted as long as they did before being supplanted by jet (gas turbine) engines precisely because of how much easier it was to build and maintain them.
  - perilunar 8y ago
    Funny you should say that. I always thought that jet engines rapidly replaced piston engines because they were easier and cheaper to build. For example, the Wikipedia article on the BMW003 says: "The BMW 003 proved cheaper in materials than the company's own 801 radial, RM12,000 to RM40,000, and cheaper than the Junkers Jumo 213 inverted V12 piston engine at RM35,000, but slightly more costly than the competing Junkers Jumo 004's RM10000.[10] Moreover, the 004 needed only 375 hours to complete (including manufacture, assembly, and shipping), compared to 1,400 for the 801." https://en.wikipedia.org/wiki/BMW_003 https://en.wikipedia.org/wiki/BMW_003 i.e. the first two german production jet engines were a third of the cost and took less than a third of the man-hours to build compared to piston engines of the same era.
    - ubernostrum 8y ago
      Again, doesn't contradict anything I said. An iPhone is cheaper to build today than a typical computer of the 1960s. Does that mean it would have been cheap or easy to build a current-model iPhone in the 1960s? Because that's the argument you're making here, essentially. Once you have the necessary tech under your belt, yes, you get a bunch of benefits from switching. But until you have that tech, you're probably not going to say "oh well, won't build any planes for the next few decades, because the engines we'd use today are way more complex and less useful than the ones we'll have eventually". Jet engines are simpler than reciprocating engines. I'll happily write that on the blackboard 1000 times, if you'll write "But until you have the fundamental technology for it, you can't build any jet engines" 1000 times. Also, read your own link: Completed engines earned a reputation for unreliability; the time between major overhauls (not technically a TBO) was about 50 hours. Even those early engines, despite being cheaper, and quicker to assemble, still weren't up to the point of being usefully reliable. Jet engines are hard.
      - perilunar 8y ago
        > Again, doesn't contradict anything I said. Yes it does. You said: “Reciprocating engines were far more complex mechanically, but lasted as long as they did before being supplanted by jet (gas turbine) engines precisely because of how much easier it was to build and maintain them.” I pointed out that they were not easier to build. Jet engines were. > An iPhone is cheaper to build today than a typical computer of the 1960s. That’s just being disingenuous. The first production jet engines were cheaper to build than piston engines of the same era. > you're probably not going to say "oh well, won't build any planes for the next few decades, because the engines we'd use today are way more complex and less useful than the ones we'll have eventually" It wasn’t a few decades. The first production jet engines obsoleted piston engines in fighter aircraft almost immediately. And in airliners in the 50s, by which time they were already more reliable. > Jet engines are hard. Maybe, but we've been building them successfully for 70 years. To get back to the grandparent point, What ‘fundamental technology’ is China missing that makes them unable to build advanced jet engines? Are they really so far behind metallurgy that they can’t?
- KineticLensman 8y ago
  > Jet aircraft were actually flying by the 1940s, and those engines were built using the relatively primitive metallurgical and manufacturing techniques of the day Yes, and the Junkers Jumo 004 jet engine used in the ME 262 "only had a service life of some 10–25 hours" (!) after which time it had to be replaced [0]. Admittedly German industry lacked raw materials to do better metallurgy, but in the 1940s there was a long way to go in terms of designing jet engines [0] https://en.wikipedia.org/wiki/Junkers_Jumo_004 https://en.wikipedia.org/wiki/Junkers_Jumo_004
  - southern_cross 8y ago
    Jet engines today are also routinely torn down, inspected, and rebuilt if necessary - much more often than piston engines are, I gather. But that's because of the overall materials stress and the necessary safety factors involved, not because of any general mechanical complexity. I mean, I guess you can count having all of those individual blades as being "complex", but in reality these are just the parts that make up mechanically simple fans and compressors and such.
  - sunstone 8y ago
    True and jet engines didn't really become viable until the discovery/invention of the inconel alloy that could operate at very high temperatures.

southern_cross 8y ago

Designs for the basic jet engine date back to at least the 1920s, and basic operating principles date back much, much further. Jet aircraft were actually flying by the 1940s, and those engines were built using the relatively primitive metallurgical and manufacturing techniques of the day. So, as I said, _mechanically_ jet engines are relatively simple devices. Materials, manufacturing, control systems, fuel efficiency, noise abatement and all that may be a very different story.

ubernostrum 8y ago
I didn't say otherwise. Jet engines have always been held back not by their mechanical complexity (they're mechanically pretty simple, as you point out), but by the difficulty of obtaining/fabricating materials that can withstand the temperatures and pressures of operation at the desired weight. Reciprocating engines were far more complex mechanically, but lasted as long as they did before being supplanted by jet (gas turbine) engines precisely because of how much easier it was to build and maintain them.
- perilunar 8y ago
  Funny you should say that. I always thought that jet engines rapidly replaced piston engines because they were easier and cheaper to build. For example, the Wikipedia article on the BMW003 says: "The BMW 003 proved cheaper in materials than the company's own 801 radial, RM12,000 to RM40,000, and cheaper than the Junkers Jumo 213 inverted V12 piston engine at RM35,000, but slightly more costly than the competing Junkers Jumo 004's RM10000.[10] Moreover, the 004 needed only 375 hours to complete (including manufacture, assembly, and shipping), compared to 1,400 for the 801." https://en.wikipedia.org/wiki/BMW_003 https://en.wikipedia.org/wiki/BMW_003 i.e. the first two german production jet engines were a third of the cost and took less than a third of the man-hours to build compared to piston engines of the same era.
  - ubernostrum 8y ago
    Again, doesn't contradict anything I said. An iPhone is cheaper to build today than a typical computer of the 1960s. Does that mean it would have been cheap or easy to build a current-model iPhone in the 1960s? Because that's the argument you're making here, essentially. Once you have the necessary tech under your belt, yes, you get a bunch of benefits from switching. But until you have that tech, you're probably not going to say "oh well, won't build any planes for the next few decades, because the engines we'd use today are way more complex and less useful than the ones we'll have eventually". Jet engines are simpler than reciprocating engines. I'll happily write that on the blackboard 1000 times, if you'll write "But until you have the fundamental technology for it, you can't build any jet engines" 1000 times. Also, read your own link: Completed engines earned a reputation for unreliability; the time between major overhauls (not technically a TBO) was about 50 hours. Even those early engines, despite being cheaper, and quicker to assemble, still weren't up to the point of being usefully reliable. Jet engines are hard.
    - perilunar 8y ago
      > Again, doesn't contradict anything I said. Yes it does. You said: “Reciprocating engines were far more complex mechanically, but lasted as long as they did before being supplanted by jet (gas turbine) engines precisely because of how much easier it was to build and maintain them.” I pointed out that they were not easier to build. Jet engines were. > An iPhone is cheaper to build today than a typical computer of the 1960s. That’s just being disingenuous. The first production jet engines were cheaper to build than piston engines of the same era. > you're probably not going to say "oh well, won't build any planes for the next few decades, because the engines we'd use today are way more complex and less useful than the ones we'll have eventually" It wasn’t a few decades. The first production jet engines obsoleted piston engines in fighter aircraft almost immediately. And in airliners in the 50s, by which time they were already more reliable. > Jet engines are hard. Maybe, but we've been building them successfully for 70 years. To get back to the grandparent point, What ‘fundamental technology’ is China missing that makes them unable to build advanced jet engines? Are they really so far behind metallurgy that they can’t?
KineticLensman 8y ago
> Jet aircraft were actually flying by the 1940s, and those engines were built using the relatively primitive metallurgical and manufacturing techniques of the day Yes, and the Junkers Jumo 004 jet engine used in the ME 262 "only had a service life of some 10–25 hours" (!) after which time it had to be replaced [0]. Admittedly German industry lacked raw materials to do better metallurgy, but in the 1940s there was a long way to go in terms of designing jet engines [0] https://en.wikipedia.org/wiki/Junkers_Jumo_004 https://en.wikipedia.org/wiki/Junkers_Jumo_004
- southern_cross 8y ago
  Jet engines today are also routinely torn down, inspected, and rebuilt if necessary - much more often than piston engines are, I gather. But that's because of the overall materials stress and the necessary safety factors involved, not because of any general mechanical complexity. I mean, I guess you can count having all of those individual blades as being "complex", but in reality these are just the parts that make up mechanically simple fans and compressors and such.
- sunstone 8y ago
  True and jet engines didn't really become viable until the discovery/invention of the inconel alloy that could operate at very high temperatures.