Recently, Su 57’s picture has attracted everyone’s attention because it was taken very clearly, and even the details of aircraft manufacturing processes commonly used by the outside world can be seen clearly. Su 57’s invisibility is too bad; even the rivets are directly exposed.
Sukhoi Design Bureau used ordinary cross-tapping screws. Such small parts are not found on F22 and F35. The difference is that F22 and F35 will be coated with structural glue using baked-in mesh technology. The thick invisible coating makes the “skin” smooth. The Su 57 is now in production and does have stealth coating, it does not involve stealth testing. As a result, everyone sees that it is almost the same as the third-generation aircraft.
The F22’s stealth coating is very thick and dense. The ground crew has to use an X-ray machine to locate structural glue. The problem was solved, so the related design was modified regarding the F35.
Of course, the stealth performance of the Su-57 is relatively poor, it is not fake, and there is no need to wash it. As we can see from the first picture, it doesn’t even align the gaps of the front edge flaps in the production variant Su-57. To claim Su-57 as a fifth-generation aircraft, it’s unreasonable to have gaps between the internal bomb bays.
Regarding the manufacturing process of Russia’s fifth-generation aircraft, there is also a picture that has caused everyone’s misunderstanding. Someone once photographed a “purple eggplant” Su-57 with “blue ribs” on the wings. Some people thought it was walking directly on the surface of the wing. Line, don’t go to the heart. This is a temporary sensor, which often appears during test flights. China’s FC31 also has a similar picture, which has nothing to do with the manufacturing process.
For example, when someone photographed Su 57 parked on the ground, there was a gap between its two bomb bay doors. The outside world thought its structural strength was insufficient, and its parts were deformed when flying. As a result, the bomb bay door is not closed tightly. This is also the original design of the Su-57, a native method adopted by Russian aerospace engineers to solve the problem of internal and external pressure in the bomb bay. Of course, the result of this is to sacrifice stealth performance.
The fan blades’ problem can be seen from the inlet port has been criticized. The production version of the Su-57 also has an exposed grille, and weather corrosion is visible on the S-duct inlet. The inlet will also reflect radar waves and make the aircraft visible to ground-based air defense radar.
Its stealth performance is indeed relatively poor. Su-57 can be considered lower-tier aircraft compared to the South Korean KF-21. Russia can’t fix the stealth performance of the Su-57 because Russia lacks the technology and funds to invest in new technology.
Due to different manufacturing processes, the fifth-generation aircraft cannot be produced on the same line as the fourth-generation aircraft. Due to financial constraints, Russia cannot build a new production line for the Su-57. It can only be produced with Su-30 and Su-35, so the fuselage manufacturing process cannot be re-used.
Russia’s original plan was to “jointly develop” the Su-57 with India. This way, there were more orders and funds. It is a pity that India was not fooled this time and decisively withdrew from the Su-57 project. Without export potential, the fate of the Su-57 is the same as the T-14 Armata. Building next-gen military products are still a dream for Russia.
The ducts are likely to be inlets for air cooling. There is a sizeable structure beneath the moving portion of the fins. Some space will be needed for the hydraulic actuator which moves the fins, but there is a lot of space in there, so I would be surprised if there are not also some avionics boxes inside. Once inside the aircraft structure, the air can be ducted anywhere it needs to be, but the longer the distance and the more tortuous the path, the more awkward this gets.
The larger the equipment, the greater the cooling requirement, but air inlets limit the efforts to reduce radar cross-sections. If you compare it to the F-35, notice how few holes there are in the external structure. The F-35 has a complicated cooling system using the onboard fuel, to avoid external inlets and keep its radar cross section as low as practicable.
The Russian design is flawed or has poor workmanship. The Russians believed, that it was easier to create a non-stealth airframe with minimal military R&D- due to the lack of resources (after the USSR have broken down). Money was scarce enough to maintain some of the USSR’s leftover weapons.
The engine faces are exposed from a frontal aspect, and even if partially concealed this generates a much larger radar return than serpentine ducts like those employed on the F-22 where the turbine isn’t directly visible. The general quality control on the airframe construction isn’t great either, with panels and rivets not as refined as their American counterparts. However, this is to be expected with a much cheaper program.
Conforming to the historical trend, the Su-57 lags behind Western avionics technology. Russia highly touted the prototype N036 array (1,514 T/R modules) as being the first of its kind in Russia. Still, the reality is that it’s a first-generation AESA radar while the APG-77(v)1 (1,951 T/R modules) and APG-81 (1,672 T/R modules) employed on the forty-years-old F-22 Raptor, respectively, are significantly more capable 3rd generation AESA arrays.
Russia has so far produced six N036 arrays for bench tests and flights tests. None of N036 arrays have been fitted with production variants aircraft.
While the two N036L side arrays (404 T/R modules each) theoretically would provide a larger engagement envelope for radar-guided missiles, their low power hampers their usability and lack of fusion capability Sukhoi removed side arrays from the production variant of Su-57.
Those fantastical wing-mounted L-band arrays that Kremlin trolls love to yell nonsense about are for IFF and nothing more. They certainly don’t possess any kind of magical anti-stealth capability. Even a basic knowledge of physics would tell you it’s complete propaganda.
The Su-57 also remains operating on somewhat underperforming AL-41F1 engines that infamously experienced a compressor stall during a prototype demonstration at MAKS 2011. The more advanced izdeliye 30 engines aren’t expected to be fielded until around 2025.
That being said, the Su-57’s avionics suite is undoubtedly an upgrade over Russia’s existing platforms, but it simply can’t compete with the raw strength of the U.S. military-industrial complex. It doesn’t have the muscle to stand up to a Raptor, an F-35 or even Gripen E, nor does it have the numbers or operational experience backing it.
The most significant indicator to me was India’s withdrawal from its joint effort with Russia to develop the Su-57; they were reportedly dissatisfied with the lackluster stealth capability of the production aircraft, which makes complete sense.
Developing an aircraft with advanced low observability requires a strong defense industry to push through the costly setbacks that inevitably accompany such programs and produce sufficient numbers. Still, Russia is simply unable to keep up. The PAK FA program is all but a failure, and now Moscow is pursuing yet another ambitious Su-75 fighter that the same fate will likely plague.
The Su-57 resembles more of a fourth-generation fighter in comparison to its Western counterparts.
The PAK FA program has been plagued by issues significantly more detrimental than anything experienced by the U.S. ATF and JSF programs, especially considering that all the effort devoted by Russia into developing this fighter has resulted in a whopping total of three “production” aircraft currently flyable at the absolute maximum with Soviet-era Irbis-E PESA radar and AL-41F turbofan engines.
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