If you’re not following the Su-57 because you rightfully believed that Russia was not going to procure these aircraft in sizable numbers, that the program was in limbo, or that this aircraft’s potential didn’t add up to much, now is a good time to take a second look. I think a fair bit of commentary and writing has been overly dismissive of this program based on earlier prototypes shown, and does not account for the different design philosophy and missions in mind that Russian MoD had behind the Su-57 when compared to U.S. approach to 5th generation aircraft. It’s also worth noting changes taking place to the design as it begins to mature.

I rarely write about aerospace and will walk into this subject cautiously.

BLUF: The Su-57 is a high maneuverability air superiority fighter, with a substantially reduced radar cross section compared to 4th generation Russian fighters, designed to work as part of Russian air defense to counter stealth aircraft near or within Russian airspace. This fighter is meant to team with Russia’s sizable 4th gen air force, and VHF/UHF ground based acquisition radars, to establish local qualitative advantages and help close corridors in Russian air defenses. The Su-57 is an affordable, producible option to bolster Russia’s air defense network. It will pose a major challenge for any 4th gen aircraft, and concern to stealth optimized 5th gen aviation. Yes it is a stealth 5th generation aircraft, but it is not a F-22 or F-35 clone, and the design philosophy is not based around mission requirements similar to U.S 5th generation aircraft. This fighter is tailored to Russian needs, though it has features intended to make it attractive to an export market.

On May 15th Vladimir Putin announced that Russia would sign a contract for 76 Su-57 fighters, this will buy three regiments of 24 aircraft, plus a flight of 4 possibly destined for Lipetsk combat training center. The actual contract is likely to be signed at MAKS-2019 show late August. According to Kommerstant the contract is valued at 170 billion RUB (this figure is too low), which will fully load the production line at Komsomolsk-on-Amur plant, though at a rather low profit margin of 3-5%. This plant is already busy with Su-35 orders. Alongside the Su-57 announcement, Putin also declared that a contract will be signed in 2020 for 100 Mi-28NM helicopters and 114 Ka-52M helicopters (Ka-52M variant to be created by 2022). The Su-57 buy appears to be scheduled for 2019-2028, though keeping in mind that the state armament program for 2018-2027 is revised every five years, so in 2022 there are likely to be course corrections.

Putin remarked that Russia has bought more than a thousand fixed and rotary wing aircraft 2011-2018. This is true, about 468 fixed wing tactical aviation and somewhere around 600 helicopters (I’ve not found exact figures for helicopters). The original state armament program (2011-2020) hoped to buy 52 serially produced aircraft. After 2015 the timeline began slipping to the right, and the expected order size drastically reduced. The expected order dropped to 15 aircraft by 2028, with earlier explanations from Deputy Defense Minister Yuri Borisov that can be summed up as ‘Russia’s 4th gen aircraft are perfectly fine for our requirements so we don’t need Su-57 right now.’ This suddenly changed last week to ‘we’ve not built anything like this platform in 40 years and are going to invest in 5th gen. Such a reversal is not uncommon in Russian defense practice. Russia’s purchase of 76 aircraft is considered an initial installment, Russian air force requirements were considered to be 200-250 Su-57s. Considering the aerospace sector’s performance 2011-2018, they could readily build in the 2020s once serial production is established.

Background

Su-57 is the official designation of the aircraft developed under the PAK-FA program (Перспективный авиационный комплекс фронтовой авиации), so far producing 11 prototypes, marked T-50-1 through 11. The USSR conducted research into low observable aircraft in response to the U.S. Advanced Tactical Aircraft program, yielding technology demonstrators such as the Mig-1.44 and the S-37. In 2002 Russia and India agreed to jointly develop a derivative of the PAK-FA aircraft as part of the Fifth Generation Fighter Aircraft Program (FGFA) for India. The deal was signed in 2010, with an initial investment of $295 million to jointly develop the design between Sukhoi and India’s HAL. The overall program was valued at $6 billion, with 35% allocated to Indian enterprises. In 2012 work stalled due to disagreements over financing and technology transfer. Moscow sought $5 billion from India to continue working on the program, valued at $10 billion. An arrangement was supposedly worked out in 2016 envisioned both sides investing $3.7-4 billion into the program over 6-7 years.

Mig 1.44 demonstrator

India sought more than 50 modifications to the aircraft, ranging from engines to stealth characteristics, meanwhile HAL’s role in the program declined to 13%. Delhi kept changing its mind about how many, and what type of FGFA aircraft they intended to procure, originally seeking 214 fighters with 48-66 of them modified two-seat versions. Subsequently Indian requirements changed to 144 single-seat fighters, and were further reduced to 127. In early 2018 India walked away from the program citing shortcomings in stealth and avionics. Some Russian analysts interpreted this decision as the result of the technical and financial disagreements, along with Indian disappointment that they were not going to develop the Indian 5th gen aircraft they wanted on the basis of the Russian PAK-FA. Other sources suggest that Moscow wanted India to fund at least half of the R&D, but Delhi had already spent an estimated $8 billion on 36 Dassault Rafales (in a deal mired in controversy), and essentially had no money in the procurement budget to seriously invest in FGFA.

Instead India was to receive an export version of the T-50, and in this scenario they backed out, leaving the development risk to Russia, with the option to come back and buy the Su-57 if Sukhoi proves successful. Why India believed they could co-develop a 5th generation aircraft program with Russia, gain experience and tech transfer, for a fraction of what similar such programs typically cost, remains a mystery. Similarly, some Western analysts and commentators began writing off the PAK-FA when India backed out, as though the $4 billion that Russia never actually received from Delhi was going to make or break Russia’s 5th generation program (a country that spends 1.5 trillion RUB on R&D and procurement per year). Many of these predictions of Russian next gen weapons programs entering ‘death spirals’ are simply wrong.

Reasons for the delays found in defense news articles typically reference something about a lack of money, sanctions, or other analytical spaghetti thrown at the wall. There is no evidence that the PAK-FA program suffers from these problems. A simpler reason is that developing a 5th generation aircraft is not all that easy especially if you’re integrating a host of new capabilities, from an AESA radar, to a low observable air frame (or at least an attempt at one), a new engine, flight control system, etc. Suffice it to say Sukhoi encountered challenges – here are a few visuals to illustrate:

Aircraft cost

It is difficult to talk unit cost because the aircraft is being bought in two phases, one with the AL-41F-1 engines and another with the Izdeliye 30 engine, which is currently undergoing testing. Since key components for the real Su-57 are not yet completed, it is challenging to estimate the actual price per unit. Currently it is estimated as a $2.5 billion USD program which works out at ~$35 million per aircraft. That seems deflated and cheaper than the Su-35, i.e. it just can’t be true. Ilya Kramnik at Izvestiya expects the overall cost of the program to be 400-500 billion RUB, as opposed to 170 bil RUB, which would make the recently announced price tag reflective of just the initial batch of serially produced aircraft. Plus United Aircraft Corporation is going to haggle over the relative price of all the aircraft it is building for the MoD such that the ultimate price per aircraft is going to only be tangentially related to the actual production cost. Most of the estimates on price seem to cluster at $45-54 million USD, or about half the cost of a F-35, not that everything should be measured in prices relative to U.S. acquisition programs.

As I have argued in earlier articles, based on purchasing power parity (PPP), as opposed to pointless conversions into average USD currency values (the kind offered to us by SIPRI), Russia spends roughly $150-$180 billion in overall military expenditure. Of this about 75% is the national defense order, with roughly 50% of that budget allocated to procurement and R&D (maybe an effective $50-$60 billion). This aircraft will have a USD based export price tag at some point, but the cost to the Russian defense budget needs to also be understood in terms of effective spending value, calculated based on PPP. This is a domestically produced aircraft, which thanks to Western sanctions, is going to be made with probably almost entirely Russian components, especially after India withdrew (not that HAL was going to do much anyway). At 2.3-2.5 billion RUB per aircraft the program works out right now to an effective $80-100 million of spending per unit produced.

Aircraft design and purpose

I think the Su-57 is a misunderstood aircraft in terms of design philosophy, purpose, and program viability. The Su-57 is a compromise between reducing the radar cross section and building a highly maneuverable air superiority fighter, with great performance at high speeds, and at different altitudes. It has innovative features which should qualify it for the 5th gen moniker, some of which I will cover later in this piece (engine, flight control, sensors, materials, etc.) That said, the Su-57 does not represent an aircraft solely dedicated to stealth and beyond visual range combat on the basis of first look/first kill.

The Su-57 is not necessarily intended to compete on stealth with U.S. F-22/F-35, though depending on the aspect, it may be quite comparable. It is not meant for penetrating integrated air defenses, conducting deep strike missions, or conducting offensive counter air within enemy air defenses. To compare its design for such roles is to engage in mirror imaging. The Su-57 appears intended to engage enemy stealth aircraft within its own air defenses, guided to target by ground-based low frequency radars, leveraging its own low observation properties to get closer to the adversary, and a mix of on-board sensors that can help with detecting low observable aircraft once within close range (IRST). I suspect it is intended to plug gaps or corridors in Russian air defense that may exist for very low observable aircraft.

The Su-57 has a SH121 multi-functional system consisting of N036 Byelka radars, which feature five active electronically scanned array radar antennas. Three in the X-band, one primary nose mounted, two smaller radars in the cheek position, plus two L-band matrices in the wing edges. Those can be used for IFF and electronic warfare, probably not powerful enough for any real stealth search/detection capability. Between the five AESA antennas, and the dedicated ECM suite in the tail, the Su-57 should be a capable electronic warfare platform, and leverage EW strengths to compensate for any shortcomings in stealth. The fighter could be used to establish local areas of air superiority against 4th gen aircraft, and get close enough to a stealth optimized aircraft to become a problem, especially with passive forms of detection like IRST. The Su-57 can carry the latest generation of Russian standoff strike weapons, and may have a role in intercepting high value air assets as well, such as AWACS. It has already been shown firing a Kh-59MK2 air-to-surface standoff guided missile.

There was no discernible Russian desire to build an advanced sensor fusion platform that could integrate with a other ISR infrastructure, or for the aircraft to serve as an ISR platform for the rest of the force. They were not seeking a stealth optimized strike and recon platform for penetrating strikes. On the whole, there is considerable doubt in Russian circles on the viability of stealth in general, and a strong belief that aircraft must retain high performance flight characteristics – including so it can survive in a post-stealth world. Russia deployed low observable cruise missiles well before the Su-57, and in general, there is stronger interest in making long range guided weapons low-observable rather than planes. There is some suggestion this plane will team with Okhotnik-B or prospective drone platforms, but that may be aspirational at this stage. The potential Su-57 pairing with Okhotnik-B is unclear, but the Russian drone is remarkably large, and may offer an additional sensor suite for queuing.

From a stealth perspective, there are problems with the airframe design as is, but these were conscious choices by the designers. It has features of a high altitude interceptor, maneuverable dogfighter, and effort was made towards reducing the RCS via shaping compared to previous Russian 4th gen fighter designs. The patent filed acknowledges that the core requirements were a contradiction (that never happens in acquisition programs!), therefore the aircraft is inherently a compromise. The fighter features maneuverability at high angles of attack, great aerodynamic performance at supersonic speeds, and good aerodynamic performance at subsonic speeds, supercruise in the final engine, an internal bay capable of large payloads, and a substantially reduced radar cross section probably in the .1-.3m² range just based on shaping. When factoring in radar absorbing material, radar blockers, etc. it could be quite lower than .1m² and grant the aircraft very low observability.

Patent text for those interested:

“Изобретение относится к многорежимным самолетам, эксплуатируемым на сверх- и дозвуковых скоростях полета, в широком диапазоне высот полета. Преимущественная область применения изобретения – многорежимные сверхманевренные самолеты с крейсерским полетом на сверхзвуковой скорости и малым уровнем заметности в радиолокационном диапазоне.

Создание самолета, способного выполнять задачи в широком диапазоне высот и скоростей полета, обладающего возможностями сверхманевренности и, при этом, имеющим малую заметность в радиолокационном диапазоне длин волн, является сложной технической задачей.

К аэродинамической компоновке такого самолета предъявляются требования максимизации аэродинамического качества (увеличению подъемной силы и уменьшению силы лобового сопротивления) на до- и сверхзвуковых скоростях полета, обеспечению управляемости на сверхмалых скоростях полета. К внешней форме планера предъявляются требования по снижению радиолокационной заметности. Все перечисленные требования являются противоречивыми, а создание самолета, отвечающего подобным требованиям, представляет собой определенный компромисс.”

To read the patent you can click this link, it’s either totally safe or I’ve already infected my computer.

Here is the stealth patent and the patent for the air intake, including radar blocker.

To stealth or not to stealth?

Disclaimer: Here we start to enter swampy waters. I’m not an engineer and can only discuss this topic in layman’s terms. I’m happy to be yelled at by actual engineers or people from the aerospace industry.

The Su-57 features a substantially reduced radar cross section compared to a typical Russian 4th generation aircraft, but this is a somewhat abstract way to discuss the subject. When we think about having low observation qualities or a small radar cross section (RCS) we are thinking about detection and engagement ranges from a particular type of radar, at a select band, and aspect. An aircraft could have a small RCS in m² when looking at it head on, but become rather visible from the rear aspect, sides, or when looking at it from below via ground based radar. It could have a tiny RCS to a X-band fire control radar, but be clearly visible to a VHF radar employing a wavelength of 1 meter or longer. A more technical paper, for example this one, explains the subject reasonably well:

“if a typical air-defence radar could detect a target with an RCS of 1 m² (small fighter) at 200 nautical miles (NM), it would detect a target of 5 m² RCS (large fighter) theoretically at 299 NM (however, the upper limit of most ground radars is set to 255 NM). A reduced RCS fighter of 0,1 m² RCS would be detected at 112 NM and a stealth fighter of 0,001 m² RCS would be detected at 36 NM. The same logic applies to any kind of radar. However, concerning fighter aircraft radars, as well as air-to-air missile seeker radars, the respective ranges are considerably shorter compared to the ones of a ground radar. In theory, the RCS of some simple objects, such as a perfect sphere, can be well defined. In practice, most targets are rather complex objects and their RCS usually fluctuates considerably, as they move with respect to a radar.”

Some commentators see the Su-57s design as a the wrong approach, unable to replicate a F-22 or F-35. As a consequence the design choice is incorrectly attributed to Russian inability to design a stealth aircraft, or some innate deficiency in the aerospace sector, for the simple reason that it’s inconceivable Russians might understand all the same things about modern air combat, and pursue a different design philosophy. This is mirror imaging. The Su-57 is not the result of a failure to execute. There are significant gaps in industrial capacity between the U.S. and Russian aerospace sector, materials, precision molds, additive processing, electron beam welding, yielding tight tolerances etc., but this is not the primary input into the Su-57 design.

The U.S. has placed most of its 5th gen eggs into the basket of stealth optimized platforms meant for beyond visual range combat, air defense penetration, and offensive counter air (if I’m wrong please yell at me). A substantial amount of money has been invested in this philosophy. The Chinese have to a large extent copied these designs, because that’s what they do. Russians think differently about stealth and the role of tactical air power in general. It is there to be one element of an integrated air defense network, and to support the ground force at the tactical-operational level, not to conduct aerospace blitzkrieg. Despite having access to plenty of information on stealth, a technology that’s at least 40 years in exploitation at this point, they developed different requirements for the aircraft.

Russia’s aerospace sector knows how to make good airframes, though not with the same tolerances, close fits, or materials. The Su-57 airframe has aspects that were clear structural choices not to invest heavily in stealth optimization at the cost of other requirements, the T-50 patent filing showed a planned RCS of .1-1m² based on shaping, though it does not include composites, radar absorbing, and radar blocking materials. So the target performance is a bit of a question mark. The biggest sources of radar reflection appear to be conscious choices.

There are oft cited statements in 2010 by the chief engineer, Alexander Davidenko, that the RCS was .3-.4 square meters, which is far higher than the potential .001-.01 m2 on a F-22. Unfortunately this is not exactly what he said. Davidenko said in 2010 that the F-22 has a .3-.4 m² RCS and that they are working with similar requirements for radar visibility. The actual RCS is undoubtedly a state secret, and Davidenko may have the wrong RCS for the F-22. He is also most likely giving out an average RCS as opposed to the RCS from a particular aspect. The point being is that he never said what the T-50 RCS actually is, from what aspect, in what frequency, or whether it was an average assessment.

Some see these comments as being in reference to shaping only, not the net RCS reduction after radar absorbing materials are factored into the equation. Those statements are also quite dated at this point, not reflective of improvements to successive air frames, though it’s reasonable to assume that the average Su-57 RCS would be somewhere in the .1-.3 range – but much lower from the frontal aspect.

Comparing Su-57 RCS to F-22 RCS is not especially helpful for two reasons. First, neither number is actually known, and the internet is awash with derived RCS figures that are relatively baseless. Second, there is no such thing as a general RCS value. The RCS is a conversion from the measure in decibels (dBsm), which varies depending on radar frequency, power, aspect of the aircraft being seen by the radar, and other factors.

It is doubtful that the Russian defense industry could build something optimized to the level of F-22 or F-35 from all aspects, because of the dedicated industrial processes required. It would entail considerable developmental risk, investment, and little payoff given the requirements. Yet the Su-57 does appear to be a very low observable design, particularly from the front aspect. The unit cost would also prove prohibitive for Russia to procure it in meaningful numbers. An optimized stealth aircraft that could not be built, or prove financially ruinous, would have been a brilliant yet somewhat pointless design. The airframe has good potential, and successive prototypes show attention to further RCS and IR signature reduction, though shortcomings are going to remain.

Judging the design based on the first series T-50 prototypes, without further investments in optimization, or the actual Izdeliye 30 engine, is probably a bit premature. Borisov made clear they would be revising the design, and a detailed look at the prototypes shows changes. After the first five prototypes, there were visible changes in the next three, according to Piotr Butowski. Three of the latest airframes (T-50-7,8,9) have an internally reinforced fuselage, panels that close the fuselage have been replaced with composite materials, the rear boom housing an EW suite has been lengthened, there are changes to the underside of the tail section, wingspan has increase from 14 to 14.1 meters – and the fuselage lengthened from 19.7 to 20.1 meters according to Butowski. The prototype T-50-9 was the first to feature a full electronic suite, which will be installed on the serial production model, as opposed to earlier examples that demonstrated partial kit.

One forum had a good example of differences in this image:

There is a 2.5 year gap between #5 and #6, with the latter series showing modifications. The prototypes currently produced are meant to test different components of the aircraft – they are not the same, and as such looking at an image of any specific model and taking it for an example of the serially produced variant could prove a mistake.

Design considerations

The inlets – these are a clearly a compromise in favor of performance over stealth, as Bill Sweetman wrote, “They are serpentine but the curvature is insufficient to obscure the entire engine face (as on the F-22, F-35 and Eurofighter Typhoon), so they also feature a radial blocker similar in principal to that used on the Boeing F/A-18E/F Super Hornet. Unlike the F-22 inlets, however, they feature a variable throat section and spill doors on the inboard, outboard and lower surfaces of the ducts. The result is a complex multiple-shock pattern at supersonic speed, which the Russians consider essential for efficient operation at Mach 2. The inlets also feature clamshell-like mesh screens and diverter slots to keep foreign objects out of the engine, as used on the Su-27 family.” The radar blocker could be a strong solution if it bounces radar waves multiple times inside the inlet prior to any return, then the blocker may prove quite effective, though its unclear the impact on performance. Currently the inlet design forms one of the main reflective surfaces looking head on at the aircraft.

The engine – the original AL-41F-1 (Izdeliye 117) is underpowered for the airframe, it is an interim power plant derived from the engine currently on the Su-35 and used on the prototypes, while Izdeliye 30 is developed. The AL-41F is a modernized variant of the AL-31, supposedly with 15% more power. Some batches of Su-57s will have to be bought with this engine, and perhaps retrofitted later. Izdeliye 30 is not expected to be completed until 2025, but will offer supercruise, delivering supersonic speeds without having to use the afterburner. It is not only more powerful, with 3D thrust vectoring, but also supposedly more efficient (17-18% according to Butowski). Top speed is set as Mach 2, supercruise at Mach 1.3. Izdeliye 30 has begun testing on one of the prototypes as of December 5, 2017 where it was seen launching from M.M. Gromov flight test center. That engine’s appearance seems to have a reduced cross section from the rear aspect in mind, when compared to the standard AL-41F-1.

Izdeliye 30 being tested on the left

The oft touted feature is 3D thrust vectoring, compared to 2D on the F-22, or no thrust vectoring on the F-35. This is useful at high altitude, for maneuverability within visual range, and certain scenarios, but is not an especially useful feature for beyond visual range combat. The Su-57 will be able to out fly most aircraft, if it can get near them and not be shot out of the sky at long range by a superior 5th generation platform – the latter scenario remains in question.

Radar – The aircraft features the N036 Byelka radar system with five AESA arrays, 3 X-band and 2 L-band. These have good potential to be used for electronic warfare, and IFF, along with the dedicated L402 ECM suite in the tail. The L402 Himalays ECM uses its own arrays and those of the N036. The N036 is a first generation AESA, and it will be the first AESA mounted on a Russian fighter. The wing leading edge extensions house two L-band matrices covering a combined 270 degrees. It’s doubtful that the L-band matrices have the power to search for a stealth aircraft in any meaningful way. They can determine range and bearing of a target, not height. Their resolution is insufficient to provide guidance to weapons. Turning them on will reveal the position of the aircraft using them well before they are likely to detect anything. L-band is typically reserved for large ground based radars because of the antenna size required to make effective use of this wavelength. Beyond IFF, and EW, it’s unclear what the L-band matrices are for – perhaps utility can be improved via networking between multiple aircraft. Could be part of a kitchen sink approach to countering stealth, reminiscent of the USSR sticking lots of non-acoustic detection sensors onto its submarines to compensate for capability gaps in acoustic detection.

IRST and DIRCM – The front mounted IRST turret is 101KS Atoll, a useful passive IR sensor, though having the ball turret in the front compromises stealth looking head on. It rolls back to reveal a surface covered with radar absorbing material, but that sphere is a no-no for stealth optimization. The 101KS might make the difference in the aircraft’s ability to search and target stealth aircraft, particularly in an environment contested by heavy use of jamming. Again, here the wavelength matters, as individual IRST may offer passive detection at relatively closer ranges, whereas there is investment in the U.S. in long wave IR detection as a counter-stealth technology. Overall the IRST system makes more sense than L-band for stealth hunting, but they would need to do something about the turret shape. The system does much better searching when queued, which the aircraft could attain via datalink from air defense radars.

Targeting pod

Other electronic features of note include the 101KS-O directional infrared countermeasure (DIRCM) turrets, IR sensors to help improve pilot awareness, and recent testing with the 101KS-N externally mounted targeting pod. These features don’t appear well integrated into the airframe, and in their current configuration further compromise stealth characteristics. They may form part of an integrated missile approach warning system. Targeting pods represent useful features for multirole functionality, but better geared towards the aircraft’s competitiveness on the export market.

T-50-9 with DIRCM mounted (system can be seen behind cockpit)

Airframe design – early prototypes suffered stress fractures in the airframe, which required internal reinforcement. This was one of the issues that led to delays in the PAK-FA program. The overall design appears cramped, with uneven surfaces along the underside, round shapes, exposed grills in the first series of T-50s, etc. Some of these deficiencies have been addressed between T-50-5 and T-50-6 (this seems to be where the 2.5 year gap may have gone). T-50-9 is the first exemplar of both RCS improvements and the full onboard electronic kit. Izdeliye 30 should help further reduce the rear aspect RCS together with the IR signature, plus latest prototypes show cowlings and other modifications to the engine housing.

Early T-50-4 variant

The aircraft features a refueling probe, and has a rugged undercarriage with large wheels for those lovely Russian runways. The internal weapons bay appears to carry 4-6 medium range missiles, or 4 standoff guided weapons, plus two R-73 short range missiles in side compartments (I’ve not seen these open to offer proof). Given the bay size, the aircraft should be able to deliver standoff tactical nuclear weapons, i.e. it’s a good candidate for the dual capable aviation role.

Conclusion

I would not discount the Su-57. It is not a 5th generation stealth aircraft design gone bad due to failure to execute. The program has legs, and it’s going to amount to something. Even though the U.S. is quite dominant as an aerospace power, it’s important to remember we exercise analytical humility in looking at why other countries may choose a different design, based on the context of how they see air defense and their requirements. The fighter will allow Russia to attain qualitative air superiority over a 4th generation air force, and work with its own integrated air defense to counter penetrating stealth aircraft. It is a reflection of the Russian philosophical approach to the tactical aviation component of its Aerospace Forces (VKS), intended to support the strategic air defense mission first, and engage in standoff strike as part of offensive aerospace operations.

The Su-57 also reflects Russian skepticism on the money and effort that should be invested into stealth optimization and reduced RCS, representing what one could call the ‘good enough’ solution to the overall air superiority problem. Maybe that’s a mistake, and they should have just cloned the F-22 to the best extent possible, but the F-22 and F-35 work in part because they belong to a large infrastructure of logistics, stacks of ISR, datalinks, support platforms, and all the pieces that make the U.S. succeed as an expeditionary aerospace power. Russia is primarily a land force, where the other services provide support at tactical-operational levels to a strategic land campaign in the theater of military operations. An F-22 clone seems somewhat overkill for that mission, and a F-35 clone makes no sense at all for an air force that has no need to operate within integrated enemy air defenses.

The fighter will also offer Russia’s aerospace sector experience in producing a 5th generation aircraft with the attendant materials/composite requirements. In this regard it reflects limitations of Russia’s military industrial complex, but even if they could replicate the same industrial processes, the unit price could prove prohibitive given all the other competing modernization priorities. Moscow can purchase several regiments of these aircraft at a fraction of the price of Western analogues, and with multirole features the fighter could prove attractive on the export market. Current program cost and production requirements are within the industry’s ability to deliver, assuming they can get the engine work completed 2020-2025. Sticking to timelines is not something industry does well. However, I would not be surprised if India came back to buy it after shifting all the risk and development cost to Russia. The airframe is likely to evolve over time into something less observable – the overall direction is better optimization for stealth.

Comments/criticisms welcome as always. Dealing with aircraft requires a tremendous amount of technical knowledge and is at best a layman’s area for me, so maybe the less I touch on it the better.

Update: had some good feedback on how to interpret patent, and a few other design items. Overall update is that patent numbers should be interpreted as providing average RCS based on shaping only, prior to RAM application, and other features (radar blockers/IRST coating) suggest that the front is VLO optimized. So I’ve gone back to edit a bit – overall conclusion remains the same, but I’m more convinced about the aircraft stealth characteristics than how I looked at the design initially, though I was much more positive on Su-57 than many of the posts out there to begin with.

Here is a closing shot of Putin walking away as billions in RUB of Russian taxpayer money finds a new home.