4 ms·

It's obvious to me that China doesn't care that much about the AN-225 design as for the design of the D-18 turbofan. They still can't design or manufacture a he

by ovi256 10y ago

It's obvious to me that China doesn't care that much about the AN-225 design as for the design of the D-18 turbofan. They still can't design or manufacture a heavy turbofan domestically. This has seriously hampered their heavy airlift project (the Y-20, who first flew using Soviet-designed low-bypass 12-ton thrust D-30 fans, which killed its range). The domestic WS-20 turbofan design that was supposed to power the production Y-20 airlifter is still under wraps, which usually means the prototype is not doing well. Getting access to a 20-ton thrust high-bypass turbofan design is a huge step for them.

wallace_f 10y ago
Why is it difficult enough that not even a nation state as large and powerful as china has obstacles to develop a heavy turbofan? With respect to other tech they've developed I don't know what is technologically difficult here -- I'm asking genuinely as a layman, it's not a rhetorical statement of disagreement.
- crawshaw 10y ago
  Fluid dynamics and combustion chambers. It's rocket science, a long, expensive trial-and-error development process. And unlike other sciences, most of the results are never published so each entity has to recreate the foundations themselves. It takes money, time, and dedicated careers.
  - vasili111 10y ago
    Why not to just buy one aircraft and reverse engineer its engines? What is the problem with just copying exact copy of existing engine?
    - clintonb 10y ago
      In this case U.S. government restrictions probably restrict China from buying U.S.-manufactured planes. I doubt Antonov wants to sell its only An-225.
      - qaq 10y ago
        Antonov is selling the unfinished frame of second AN-225 and rights and documentation as far as I remember.
      - coredog64 10y ago
        The Chinese buy plenty of U.S. manufactured planes. In fact, in order to convince China to buy large aircraft like the 777, Boeing was more than happy to sign offset agreements[0] that sent a significant portion of manufacturing of smaller aircraft to Chinese subcontractors. Lest you think I would only throw stones at my former employer, Airbus has been doing that and more. They are actually doing final assembly in China. [0] https://en.wikipedia.org/wiki/Offset_agreement https://en.wikipedia.org/wiki/Offset_agreement
    - avar 10y ago
      This thing is not exactly something you can just order online at http://www.antonov.com http://www.antonov.com Obviously if China wants to buy one the fact that they want to reverse engineer its technology is going to be patently obvious. Even if China could get a hold of an AN-225 reverse engineering one is a huge task, and at best you only know exactly what this hardware did, not what they avoided, or good ideas they didn't pursue purely due to resource constraints etc. So what happens instead is that a state like China approaches the Ukraine for a manufacturing agreement like the one described in the article. China hands over a lot of money which covers not just the planes but also the tech, and job are created in the Ukraine as a result.
    - dogma1138 10y ago
      Because a lot of the "knowledge" comes from the engineering process much of it is trial and error and often it's not documented in the theoretical books ;) This is why it's easy to lose the ability to produce something e.g. the big rockets that NASA used to make. China can make a copy of the engine but it would not gain sufficient insight into why they chosen to design it exactly as it did so making adjustments would not be very easy or possible at all without putting almost as much R&D effort into it as making a whole new engine from scratch and debugging things would also be near impossible. There is a reason why there are only a few engine manufacturers in the world, it's very hard work, and as far as big engines go then only RR and GE are really in the game.
      - DashRattlesnake 10y ago
        > This is why it's easy to lose the ability to produce something e.g. the big rockets that NASA used to make. IIRC, to avoid this when they shut down F-22 production, they crated a huge number of DVDs documenting every step of the manufacturing process, so that knowledge wouldn't be totally lost.
    - rayiner 10y ago
      Modern turbofans only stand up to their extreme operating conditions because of the use of exotic alloys and elaborate cooling techniques. Just because you know what shape a turbine blade should be doesn't mean you can copy the exotic alloy and manufacture it in a way that results in the correct crystal structure.
      - semi-extrinsic 10y ago
        Not only exotic alloys, but single crystal blades. That's right, the blade is machined out of a single atomistically perfect crystal with no defects what so ever. The main point is that this reduces thermal creep, meaning you can have tighter tolerances and more power/efficiency.
        rayiner 10y ago
        Also, because combustion temperatures can exceed the melting point of the alloy, HPT blades often have a complex set of internal hollows and holes at the surface for cooling air. Air can be passed through to create a boundary layer on the surface that prevents the surface from heating up past the melting point of the alloy.
        dmoy 10y ago
        Holy crap that is nuts. Towards the middle/end in here: https://www.theengineer.co.uk/issues/june-2015-online/jewel-in-the-crown-rolls-royces-single-crystal-turbine-blade-casting-foundry/ https://www.theengineer.co.uk/issues/june-2015-online/jewel-... Also cool to hear them talking about automating as much stuff as possible to remove human error. Incidentally that's also how we go about software release processes where I work.
        Osmium 10y ago
        > single atomistically perfect crystal with no defects what so ever Nit-pick, but single crystals can (and do) still have defects. Your point about single crystal turbine blades being awesome I agree with completely though :)
    - hourislate 10y ago
      I'm not an expert in the field of reverse engineering but I have read in the past that it can be extremely difficult and end up costing more in time, effort, money than designing from scratch. China has the luxury of being able to play catch up by purchasing technology. Why spend the next 20 years trying to develop it when you can pay Ukraine who already has the expertise/product and probably gave the Chinese a deal. It's just smart business. China apparently did something similar with BMW. They bought a BMW factory in Brazil (I think) for a couple of billion and disassembled it piece by piece and moved it to China. It saved them years of figuring out the how to of high tech auto engine manufacturing. Link to Story: http://tech.mit.edu/V126/N4/4long4.html http://tech.mit.edu/V126/N4/4long4.html
- icegreentea 10y ago
  Should probably begin by saying that there's no fundemental reason why China could not eventually develop their own modern turbofans without outside assistance. But obviously now is better for China. Designing and building modern turbofan engines is incredibly dependent on your mastery of materials science and fabrication. These are areas of science and engineering that are notoriously "art like" or even "black magic like". The accrued knowledge that sits in Rolls-Royce or GE or Pratt-Witney don't really exist in textbooks, and they aren't taught in classes either. This knowledge and know how was generated over 60 years of trial and error, and are jealously guarded, not just by the manufacturers, but also by their governments. Things to consider: modern turbine blades are already pushing the absolute edge of lightweight-temperature resistant materials. And then modern designs will run these blades at temperatures that are nominally above the material failure point, because we've come up with ways to cool the structures. Oh, and the temperature resistant alloys in use? Secret. Empirically determined, and likely unique.
  - rmelly 10y ago
    Pretty much this. Incredibly hard to design from scratch; cheaper to buy an existing design and start from there.
  - fma 10y ago
    This being China...what are the chances they can buy existing designs and reverse engineer them and improve then so they don't start from scratch. They've done it before...
    - icegreentea 10y ago
      Well, they've almost certainly been trying that. And as the OP said, it hasn't been paying off in a big way. If they've been doing it (I'm guessing they have), then they've probably benefitted, just not enough for the big win. Once you get into materials and fabrication, having a finished example to examine is rarely going to lead to a big win. If the secret sauce is in the fabrication (HOW do you make a single crystal blade? HOW do you inflate corrugated titanium? HOW do get this type of grain structure with this nickel-iron-manganese mix? HOW do you get a laser weld in this impossible again?), then a single example isn't -THAT- useful. Reversing engineering a modern turbofan(remember, the basic principles of turbofans are well known) is more akin to reverse engineering Intel's fab process by peaking at a finished i7 (with AFM and electron microscopes) than reverse engineering say... a sensor fusion module once you get the assembly code. Which is why the technology transfer associated with the engine deal is a big deal. It should (I mean, its possible that the terms are all fucked up) give the Chinese an oppourtunity to learn all of these hows and whys (albeit for a slightly dated design, but still a relatively modern one).
- k_lander 10y ago
  Also, how Ukraine, out of all countries?
  - DashRattlesnake 10y ago
    > Also, how Ukraine, out of all countries? I think the Soviet Union physically based a good chunk of its military industry in Ukraine, which the country then inherited when it became independent. So when we talk about Ukraine in this context, we're talking about a former superpower.
  - PeterisP 10y ago
    Ukraine has traditionally been the location of most Soviet block aerospace engineering and manufacturing, and much of it is still being manufactured there. For example, several current models of Russian helicopters and military ships rely on engines made only in Ukraine, and the recent conflict and disruption of the military industrial complex (which used to and still is rather connected between Ukraine and Russia) has caused delays in producing these craft since you can't really replicate it easily, it takes a lot of time, skill and effort. Also, lots of military rocket manufacture (from shoulder-operated to very large SAM) was and is located in Ukraine. Together with their rather large nuclear industry (currently civilian, but they used to manufacture warheads as well, plus the missile and guidance systems) they probably could be a first-rate nuclear power with MIRV ICBMs if there was a political will to make it so again.
- rayiner 10y ago
  Developing a modern turbofan engine requires deep expertise in numerous domains: fluid dynamics, metallurgy, etc. The basic principle is easy: increase temperature and pressure to increase efficiency. But just because you know that doesn't mean you know how to manufacture a single-crystal nickel alloy turbine blade that can actually work at those temperatures and pressures.
ting_bu_dung 10y ago
it seems China is starting to militarize under its one dictator Xi, what with the island building in south china sea, desire to build aircraft engines, voicing economic/military threats to other countries when it cannot buy critical infrastructures in those countries (UK, Australia) and continued trade support for north korea (with its bigger nuclear bomb capability). It must be preparing for some sort of external conflicts, what with the internal economy crashing, wto membership ending this year, capital outflows, manufacturing moving out.
- dang 10y ago
  You've been using HN exclusively for political controversy. That's not a legit use of this site, so please don't use it that way. HN exists for the gratification of intellectual curiosity, not political battles, and the two are mostly incompatible.

by ovi256 10y ago

wallace_f 10y ago

Why is it difficult enough that not even a nation state as large and powerful as china has obstacles to develop a heavy turbofan? With respect to other tech they've developed I don't know what is technologically difficult here -- I'm asking genuinely as a layman, it's not a rhetorical statement of disagreement.

crawshaw 10y ago
Fluid dynamics and combustion chambers. It's rocket science, a long, expensive trial-and-error development process. And unlike other sciences, most of the results are never published so each entity has to recreate the foundations themselves. It takes money, time, and dedicated careers.
- vasili111 10y ago
  Why not to just buy one aircraft and reverse engineer its engines? What is the problem with just copying exact copy of existing engine?
  - clintonb 10y ago
    In this case U.S. government restrictions probably restrict China from buying U.S.-manufactured planes. I doubt Antonov wants to sell its only An-225.
    - qaq 10y ago
      Antonov is selling the unfinished frame of second AN-225 and rights and documentation as far as I remember.
    - coredog64 10y ago
      The Chinese buy plenty of U.S. manufactured planes. In fact, in order to convince China to buy large aircraft like the 777, Boeing was more than happy to sign offset agreements[0] that sent a significant portion of manufacturing of smaller aircraft to Chinese subcontractors. Lest you think I would only throw stones at my former employer, Airbus has been doing that and more. They are actually doing final assembly in China. [0] https://en.wikipedia.org/wiki/Offset_agreement https://en.wikipedia.org/wiki/Offset_agreement
  - avar 10y ago
    This thing is not exactly something you can just order online at http://www.antonov.com http://www.antonov.com Obviously if China wants to buy one the fact that they want to reverse engineer its technology is going to be patently obvious. Even if China could get a hold of an AN-225 reverse engineering one is a huge task, and at best you only know exactly what this hardware did, not what they avoided, or good ideas they didn't pursue purely due to resource constraints etc. So what happens instead is that a state like China approaches the Ukraine for a manufacturing agreement like the one described in the article. China hands over a lot of money which covers not just the planes but also the tech, and job are created in the Ukraine as a result.
  - dogma1138 10y ago
    Because a lot of the "knowledge" comes from the engineering process much of it is trial and error and often it's not documented in the theoretical books ;) This is why it's easy to lose the ability to produce something e.g. the big rockets that NASA used to make. China can make a copy of the engine but it would not gain sufficient insight into why they chosen to design it exactly as it did so making adjustments would not be very easy or possible at all without putting almost as much R&D effort into it as making a whole new engine from scratch and debugging things would also be near impossible. There is a reason why there are only a few engine manufacturers in the world, it's very hard work, and as far as big engines go then only RR and GE are really in the game.
    - DashRattlesnake 10y ago
      > This is why it's easy to lose the ability to produce something e.g. the big rockets that NASA used to make. IIRC, to avoid this when they shut down F-22 production, they crated a huge number of DVDs documenting every step of the manufacturing process, so that knowledge wouldn't be totally lost.
  - rayiner 10y ago
    Modern turbofans only stand up to their extreme operating conditions because of the use of exotic alloys and elaborate cooling techniques. Just because you know what shape a turbine blade should be doesn't mean you can copy the exotic alloy and manufacture it in a way that results in the correct crystal structure.
    - semi-extrinsic 10y ago
      Not only exotic alloys, but single crystal blades. That's right, the blade is machined out of a single atomistically perfect crystal with no defects what so ever. The main point is that this reduces thermal creep, meaning you can have tighter tolerances and more power/efficiency.
      - rayiner 10y ago
        Also, because combustion temperatures can exceed the melting point of the alloy, HPT blades often have a complex set of internal hollows and holes at the surface for cooling air. Air can be passed through to create a boundary layer on the surface that prevents the surface from heating up past the melting point of the alloy.
      - dmoy 10y ago
        Holy crap that is nuts. Towards the middle/end in here: https://www.theengineer.co.uk/issues/june-2015-online/jewel-in-the-crown-rolls-royces-single-crystal-turbine-blade-casting-foundry/ https://www.theengineer.co.uk/issues/june-2015-online/jewel-... Also cool to hear them talking about automating as much stuff as possible to remove human error. Incidentally that's also how we go about software release processes where I work.
      - Osmium 10y ago
        > single atomistically perfect crystal with no defects what so ever Nit-pick, but single crystals can (and do) still have defects. Your point about single crystal turbine blades being awesome I agree with completely though :)
  - hourislate 10y ago
    I'm not an expert in the field of reverse engineering but I have read in the past that it can be extremely difficult and end up costing more in time, effort, money than designing from scratch. China has the luxury of being able to play catch up by purchasing technology. Why spend the next 20 years trying to develop it when you can pay Ukraine who already has the expertise/product and probably gave the Chinese a deal. It's just smart business. China apparently did something similar with BMW. They bought a BMW factory in Brazil (I think) for a couple of billion and disassembled it piece by piece and moved it to China. It saved them years of figuring out the how to of high tech auto engine manufacturing. Link to Story: http://tech.mit.edu/V126/N4/4long4.html http://tech.mit.edu/V126/N4/4long4.html
icegreentea 10y ago
Should probably begin by saying that there's no fundemental reason why China could not eventually develop their own modern turbofans without outside assistance. But obviously now is better for China. Designing and building modern turbofan engines is incredibly dependent on your mastery of materials science and fabrication. These are areas of science and engineering that are notoriously "art like" or even "black magic like". The accrued knowledge that sits in Rolls-Royce or GE or Pratt-Witney don't really exist in textbooks, and they aren't taught in classes either. This knowledge and know how was generated over 60 years of trial and error, and are jealously guarded, not just by the manufacturers, but also by their governments. Things to consider: modern turbine blades are already pushing the absolute edge of lightweight-temperature resistant materials. And then modern designs will run these blades at temperatures that are nominally above the material failure point, because we've come up with ways to cool the structures. Oh, and the temperature resistant alloys in use? Secret. Empirically determined, and likely unique.
- rmelly 10y ago
  Pretty much this. Incredibly hard to design from scratch; cheaper to buy an existing design and start from there.
- fma 10y ago
  This being China...what are the chances they can buy existing designs and reverse engineer them and improve then so they don't start from scratch. They've done it before...
  - icegreentea 10y ago
    Well, they've almost certainly been trying that. And as the OP said, it hasn't been paying off in a big way. If they've been doing it (I'm guessing they have), then they've probably benefitted, just not enough for the big win. Once you get into materials and fabrication, having a finished example to examine is rarely going to lead to a big win. If the secret sauce is in the fabrication (HOW do you make a single crystal blade? HOW do you inflate corrugated titanium? HOW do get this type of grain structure with this nickel-iron-manganese mix? HOW do you get a laser weld in this impossible again?), then a single example isn't -THAT- useful. Reversing engineering a modern turbofan(remember, the basic principles of turbofans are well known) is more akin to reverse engineering Intel's fab process by peaking at a finished i7 (with AFM and electron microscopes) than reverse engineering say... a sensor fusion module once you get the assembly code. Which is why the technology transfer associated with the engine deal is a big deal. It should (I mean, its possible that the terms are all fucked up) give the Chinese an oppourtunity to learn all of these hows and whys (albeit for a slightly dated design, but still a relatively modern one).
k_lander 10y ago
Also, how Ukraine, out of all countries?
- DashRattlesnake 10y ago
  > Also, how Ukraine, out of all countries? I think the Soviet Union physically based a good chunk of its military industry in Ukraine, which the country then inherited when it became independent. So when we talk about Ukraine in this context, we're talking about a former superpower.
- PeterisP 10y ago
  Ukraine has traditionally been the location of most Soviet block aerospace engineering and manufacturing, and much of it is still being manufactured there. For example, several current models of Russian helicopters and military ships rely on engines made only in Ukraine, and the recent conflict and disruption of the military industrial complex (which used to and still is rather connected between Ukraine and Russia) has caused delays in producing these craft since you can't really replicate it easily, it takes a lot of time, skill and effort. Also, lots of military rocket manufacture (from shoulder-operated to very large SAM) was and is located in Ukraine. Together with their rather large nuclear industry (currently civilian, but they used to manufacture warheads as well, plus the missile and guidance systems) they probably could be a first-rate nuclear power with MIRV ICBMs if there was a political will to make it so again.
rayiner 10y ago
Developing a modern turbofan engine requires deep expertise in numerous domains: fluid dynamics, metallurgy, etc. The basic principle is easy: increase temperature and pressure to increase efficiency. But just because you know that doesn't mean you know how to manufacture a single-crystal nickel alloy turbine blade that can actually work at those temperatures and pressures.

ting_bu_dung 10y ago

it seems China is starting to militarize under its one dictator Xi, what with the island building in south china sea, desire to build aircraft engines, voicing economic/military threats to other countries when it cannot buy critical infrastructures in those countries (UK, Australia) and continued trade support for north korea (with its bigger nuclear bomb capability). It must be preparing for some sort of external conflicts, what with the internal economy crashing, wto membership ending this year, capital outflows, manufacturing moving out.

dang 10y ago
You've been using HN exclusively for political controversy. That's not a legit use of this site, so please don't use it that way. HN exists for the gratification of intellectual curiosity, not political battles, and the two are mostly incompatible.