Russian Su-57 Aircraft Thread (PAK-FA and IAF FGFA)

Discussion in 'World Armed Forces' started by A Bar Brother, Dec 23, 2014.

  1. Gloire_bb
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    Gloire_bb Junior Member
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  2. Tirdent
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    Tirdent Junior Member
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    Not so sure about that - there is a surprising amount of information on the systems architecture available if you know where to look (including a patent). In fact the article linked by TerraN_EmpirE provides a surprisingly frank and concise summary which indicates the philosophy may incorporate features to enable easier upgrades (like the Gripen NG segregated critical/non-critical architecture that has generated a lot of interest). This is one of the problems with the F-22 strongly centralized philosophy that has slowed the pace of its upgrades (while it is receiving some, the cost and effort is very high) because any software or hardware change automatically impacts critical functions.

    Also the type and number of CPUs (late-model Elbrus-series RISC processors) have been published. While this chip is pretty obsolete by Western consumer electronics standards, but as gelgoog noted, so are the electronics used in the F-22 and F-35 due to stringent military certification requirements. I'm not an electronics expert, but the Elbrus seems particularly well-suited to real-time applications like this.

    As I've described on this forum before, the USSR was an early adopter of intra-flight data-linking, having it in service at a larger scale on the MiG-31 and Su-27 than the US as recently as the late-1990s and early-2000s (when the low-cost MIDS terminal enabled near-universal retrofit of Link-16). The Russians are no strangers to the concept of networking and the Su-57 is known to adopt a new, bespoke system.

    Also, Western aircraft (with the exception of Typhoon - PIRATE is a superlative capability!) are not very well equipped with IRSTs, unlike Russian fighters, so the problem is not symmetrical and supercruise continues to offer benefits for the Su-57. No IRST at all on the F-22, the F-35 EODAS is a MWIR system for better A/G performance rather than long range detection of aerodynamic airframe heating and Rafale's OSF-IT was by all accounts not a success (AFAIK later batches retain only the TV camera for target ID).
     
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  3. Brumby
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    The real hard work in avionics and sensor development are the deliverables in the form of capability output. Not in the architecture vision. As I said, showing some equipment that potentially are part of the preassembled package doesn't equate to a functional system ready to execute missions. The difference very often is 15 years or more of developmental timeline. in other words show me the tangible evidence that progress is being made and not claims of progress.

    The Russian IRST systems were non-imaging type and several generations behind western standards even with OLS-35. What can you tell me about OLS-57? .
     
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  4. Tirdent
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    Uncooled IIR sensors have dramatically improved in performance recently, but for a long-range detection system like an IRST (as opposed to a missile seeker or MAWS sensor) cooled systems are still the way to go. Higher cost, complexity and weight, so uncooled sensors are popular for the applications I mentioned previously, but PIRATE is definitely cooled for good LWIR performance (it has an additional MWIR channel for imaging modes, IIRC).

    EOTS (I meant to say EOTS rather than EODAS in my earlier post too!) is a scanning system. Staring arrays are not very useful in a long range sensor but ideal for continuous wide angle surveillance (MAWS/EODAS). DDM-NG is likewise a scanning sensor though - this enables near-spherical coverage with only two sensors rather than 6 on installations like the F-22, F-35, J-20 and Su-35 (a cost and space constraint).

    Yes. When was that graphic created and which Su-35 does it refer to? Although the second question is pretty much rhetorical admittedly, because the current Su-35S (as opposed to the 1990s Su-27M with canards which never entered service) is known to use a fiber-optic avionics bus. Do you honestly believe that would be this low in bandwidth?
     
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  5. Brumby
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    It is not for me to believe or not but it is being quoted that the SU-35 is using a mil-std 1553b data bus. If you have sources that are reporting a different data bus adoption I am happy to be updated.
     
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  6. Tirdent
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    Tirdent Junior Member
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    Since I'd have to be an insider to have that information and would be under NDA not to publish it if I was, that's clearly impossible. We don't even have that confirmation for Western avionics architectures either, for the exact same reasons, so what's the point? We can chose to believe or disbelieve, but that's about it.

    That's because they came decades before today's Western IRSTs. OLS-35 is pretty much an evolution of those systems with an A/G imaging channel added, so yes it's no match for PIRATE but this is not necessarily an indication of the capabilities of a clean-sheet design. No specifics have been released about the Su-57's 101KS-V.

    http://www.knaapo.ru/media/rus/about/production/military/su-35/su-35_buklet_rus.pdf

    Page 6: Волоконно-оптические и цифровые мультиплексные линии связи = Fiber optic digital multiplexed data buses
     
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  7. gelgoog
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    gelgoog Senior Member
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    The F-22 software was programmed in Ada and reused a lot of prior code. The F-35 software avionics were totally rewritten in C++. So no, it might use similar concepts in some ways, but it is all new. In fact this decision is probably the main reason for the delays with the F-35.

    The F-22 does not have an IRST because back then the West was simply behind on that particular technology. In particular the USA. Originally the US considered such systems too expensive and unreliable. That perspective only changed when NATO had access to the MiG-29 in West German service. The only people who worked on similar systems in the West back then were the South Africans and the Israelis. Those countries had more combat exposure to Soviet fighters so they realized the problem with not having IRST and helmet mounted sights earlier. Similar reason why it originally did not have the AIM-9X.

    With regards to the Su-35 I have enough data on it to know that it has nothing to do with prior Flanker series avionics. On seeing that diagram I question which Su-35 they are talking about. Also, like I said, the Eurofighter has less advanced avionics than the F-22. The databus is also worse like your diagram shows. So thank you for proving my point that the Eurofighter has really ancient avionics in it.

    My talk about comparing chips does make a point. Ever heard of Moore's law? The Russians have better processors available to them than either the i960MX processors used in the F-22 or the PowerPC processors initially used in the F-35. AFAIK Russian military-industrial projects in aviation and space use some Elbrus derivative of the SPARC architecture. Probably the MCST-R1000. That is a quad-core 64-bit CPU with vector instructions fabbed at 90nm. Which is outdated but less so than the PowerPC processors used in the F-35. Let alone the i960MX.
     
  8. Gloire_bb
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    Gloire_bb Junior Member
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    That's wrong. US had better IRSTs on F-14 series.
    But f-18 series dropped them(partially making up with a2g pods), and USAF never really felt the need(iirc, IRST was one of longer-surviving NAVAIR requirements from the NATF days).
    TBH, i was surprised when they decided to adapt it to their 4th gen birds.
    Change of the prospective may have actually affected Europeans, but not the US.
     
  9. Tirdent
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    Tirdent Junior Member
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    Yes, relative to other IRSTs at the time AN/AAS-42 was extremely impressive as well, so much so that most current US products (TigerEye, Legion, IRST21) still draw heavily on it. All in all it only ever equipped a small fraction of the total US fighter fleet due to high cost (same story with its modern day off-shoots) and as it was LWIR only and generally based on older technology its imaging capabilities are markedly inferior to PIRATE. That's why it was often teamed with the older TCS TV-system for target ID on the F-14.
     
    #2829 Tirdent, Mar 9, 2019
    Last edited: Mar 9, 2019
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  10. Brumby
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