Sukhoi Su-57 flight testing and development

From the FB ( 25 April '26 ) :

''In the early morning, the Ukrainians launched another attack with drones of the aircraft type on a target located in the deepest rear, in the heart of Russia.
Or rather, they tried to launch an attack. They attacked, if I'm not mistaken.
Plus or minus 1800 km. 8-10 hours of flight.
There can be no talk of any corridors through the Baltic countries here. This once again confirms that they didn't need any corridors. They easily fly these 1800 kilometers over our territory. We'll read the Defense Ministry's reports on the downed drones later, and we'll be able to estimate how many of them were launched in this direction.''

https://t.me/bomber_fighter/25039
 
Yellowflash said:
Can someone be kind enough to explain why Su57 didnt go with a faceted IRST dome and instead used a semi-spherical one? what are the design trade off for both?
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Building on the basis of previous systems, most likely ease of manufacturing as well as many of the same processes and equipment are already in place. As for faceting, if the models, artwork and three-views are to be believed the LTS will have both, the already known IRST and EOTS similar to that of the F-35. T-75B, the proposed unmanned version would forego the spherical IRST entirely though, one has to assume that it's not considered worthwhile to keep it when the removal of the cockpit would already erase a major source of radar returns, so perhaps it was deemed worthwhile to consider going all in on signature reduction.

Furthermore, keep in mind that the Su-57 is the first low observable manned aircraft developed and constructed in Russia, thus it leans heavily on work, processes and in a more limited way also individual components lifted from previous endeavours (parts of the engines being the most famous example).
 

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EmoBirb said:
Building on the basis of previous systems, most likely ease of manufacturing(...)
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Flat mirror is easier than bulb (and in any case, su-57 has lots of flats).
Bulb is optimal for powerful laser though, and one way to explain it is that since DIRCM turrets are IRSTs, it's quite normal for IRST turret to also be a DIRCM.
Especially as it just happens to sit exactly in the dead sector of the other two.
EmoBirb said:
T-75B, the proposed unmanned version would forego the spherical IRST entirely though, one has to assume that it's not considered worthwhile to keep it when the removal of the cockpit would already erase a major source of radar returns, so perhaps it was deemed worthwhile to consider going all in on signature reduction.
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Russian IRSTs are very much WVR sensors working in tandem with HMS (which of course can do more).
Without cockpit, IRST loses significant part of it's value. Though hopefully manned aircraft will lose bulb as well: it looks out of place on 75. Expensive redundancy is the su-57 way.
 
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Ainen said:
Russian IRSTs are very much WVR sensors working in tandem with HMS (which of course can do more).
Without cockpit, IRST loses significant part of it's value.
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I don’t agree with this part. IRSTs enable you to track a target passively within mostly sub-100 km BVR ranges, head-on, without alerting your opponent that you’re locking onto them, pretty much right up until the missile seeker acquires the target. In the era of LO aircraft and 5th gen aerial warfare, their utilization has become massively important.

I mean, speaking of the value of equipping unmanned fighters with IRSTs, the Turks integrated an IRST with faceted housing onto the Kızılelma, for crying out loud (and have even tested expected scenarios where an IRST-equipped Kızılelma shares targeting data over tactical datalink with a sensor-less Kızılelma). Its value is clearly still there (in fact, this would be an understatement!).

screenshot-2025-12-31-182110-png.796974


View: https://youtu.be/DE1C39KA3wY?si=q-BWPMk-Jyq2dBdO
 
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snne said:
I don’t agree with this part. IRSTs enable you to track a target passively within mostly sub-100 km BVR ranges, head-on, without alerting your opponent that you’re locking onto them, pretty much right up until the missile seeker acquires the target. In the era of LO aircraft and 5th gen aerial warfare, their utilization has become massively important.
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IRSTs are different. Some are full sized mirrors with limited movement, going into LWIR(detecting heated surfaces over long range). Those are obviously ambush/bvr focused; but usually no laser for you, it's search/track. Plus, foggier image.

Others are much smaller mirrors with in-built laser rangefinder, capable of matching most of pilot head movement(60 deg). They are more of wvr tools, as while mwir captures really hot objects(tracking falcon 9) from afar, overall atmosphere absorbs mwir way better. Image it can generate is sharper, though.

Frenchmen combined best of both worlds(pure dual band IRST + pure visual TV+LRF, and gave them impressive downwards angle, plus mixed them with mica-ir feed), but at expense of huge optical "cassette" and moving radar forward almost as if it's a secondary sensor (never backfired).

Finally, there's EOTS - which in principle is the same(mwir, LRF in), but they tend to be far worse scanners due to entirely different design focus(which is picture quality for ground target observation and recognition), and their FoV is literal opposite of pilots' cockpit. Which doesn't mean it's useless(certainly useful), just a different focus.

Su-57 has all, 720, at the same time (though no internal EOTS) - i.e. it isn't really meant to be offensive aircraft, fighting more like a better 4th gen in this regard (throwing stand off strikes).

On a more affordable Su-75, since it has EODAS- and EOTS- like systems, IMHO, separate IRST isn't really worth it. Not worth the money (and it isn't cheap). Plus it most certainly looks like an offensive aircraft: signature penalty is undesirable.
On the other hand, it can take MRAAMs in fast bays and it has lower G-rating; was WVR that important for design? Drone hunting is better done through EOTS(lower hemisphere and image quality being big advantages), which is there.

Turkish case is unique in my opinion, as TAF really needs whatever a2a capability it can claim, asap, yesterday. Otherwise, it would be far too comprehensive of a suite for a relatively light subsonic drone.
 
Ainen said:
Russian IRSTs are very much WVR sensors working in tandem with HMS (which of course can do more).
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We must keep on mind that the old OLS-27 in the Su-27 'FFF' was rather for the BVR combat with max 100 km detection /tracking range and in conjunction with the medium/long range R-27T/ET.Same story goes with the newer longer range OLS-30 and OLS-35.Also there is IRST 8TK in the MiG-31BM which can work together with the N007AM in the Cooperation mode as the leading or trailing FCS 's channel (same case with the Su-27/30 FFF ) .This time there is no more IR guided R-40TD/TD-1. On the other side, old KOLS/Izd.13S in the MiG-29 was only for the WVR with the max 25km detection /tracking range.

When we talk about the Su-57 and its OLS-50M/101KS-V as I suppose very long range IRST , it is interesting that there is no IR guided AAM's in fact in the weaponry.
 
Ainen said:
IRSTs are different. Some are full sized mirrors with limited movement, going into LWIR(detecting heated surfaces over long range). Those are obviously ambush/bvr focused; but usually no laser for you, it's search/track. Plus, foggier image.

Others are much smaller mirrors with in-built laser rangefinder, capable of matching most of pilot head movement(60 deg). They are more of wvr tools, as while mwir captures really hot objects(tracking falcon 9) from afar, overall atmosphere absorbs mwir way better. Image it can generate is sharper, though.

Frenchmen combined best of both worlds(pure dual band IRST + pure visual TV+LRF, and gave them impressive downwards angle, plus mixed them with mica-ir feed), but at expense of huge optical "cassette" and moving radar forward almost as if it's a secondary sensor (never backfired).

Finally, there's EOTS - which in principle is the same(mwir, LRF in), but they tend to be far worse scanners due to entirely different design focus(which is picture quality for ground target observation and recognition), and their FoV is literal opposite of pilots' cockpit. Which doesn't mean it's useless(certainly useful), just a different focus.

Su-57 has all, 720, at the same time (though no internal EOTS) - i.e. it isn't really meant to be offensive aircraft, fighting more like a better 4th gen in this regard (throwing stand off strikes).

On a more affordable Su-75, since it has EODAS- and EOTS- like systems, IMHO, separate IRST isn't really worth it. Not worth the money (and it isn't cheap). Plus it most certainly looks like an offensive aircraft: signature penalty is undesirable.
On the other hand, it can take MRAAMs in fast bays and it has lower G-rating; was WVR that important for design? Drone hunting is better done through EOTS(lower hemisphere and image quality being big advantages), which is there.

Turkish case is unique in my opinion, as TAF really needs whatever a2a capability it can claim, asap, yesterday. Otherwise, it would be far too comprehensive of a suite for a relatively light subsonic drone.
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Yes, OSF is indeed more unique with the TV-sensor, but frankly, you’ll find the rest on newer systems worldwide. And when an IRST isn’t dual-band (LWIR+MWIR), it’s usually paired with an EOTS on the same aircraft, like with the Turkish designs. PIRATE, KARAT, OLS-35, etc., also have lasers for WVR combat.

Su-57 has all, 720, at the same time (though no internal EOTS) - i.e. it isn't really meant to be offensive aircraft, fighting more like a better 4th gen in this regard (throwing stand off strikes).
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Are we looking at the same aircraft? Everything about the Su-57 screams "offensive aircraft" to me, except for the fact that the 101KS-V is essentially a further evolution of the OLS family.

On a more affordable Su-75, since it has EODAS- and EOTS- like systems, IMHO, separate IRST isn't really worth it. Not worth the money (and it isn't cheap). Plus it most certainly looks like an offensive aircraft: signature penalty is undesirable.
On the other hand, it can take MRAAMs in fast bays and it has lower G-rating; was WVR that important for design? Drone hunting is better done through EOTS(lower hemisphere and image quality being big advantages), which is there.

Turkish case is unique in my opinion, as TAF really needs whatever a2a capability it can claim, asap, yesterday. Otherwise, it would be far too comprehensive of a suite for a relatively light subsonic drone.
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Although both the Su-57 and the Su-75 are clearly offensive aircraft, the -75 is meant to operate right where the action is due to its lower signature, while the Su-57 stays further back and commands everything it’s capable of. This means the -75 needs to ambush other LO aircraft without revealing its position, or else it’d be a death sentence for it or could not reliably get a mission kill.

And no, while the Turks are the first to integrate an IRST on an unmanned jet (the Chinese are tight-lipped), they’re not alone in recognizing its value. Both Europeans and Americans are either doing it or working towards it.
 
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snne said:
Yes, OSF is indeed more unique with the TV-sensor, but frankly, you’ll find the rest on newer systems worldwide. And when an IRST isn’t dual-band (LWIR+MWIR), it’s usually paired with an EOTS on the same aircraft, like with the Turkish designs. PIRATE, KARAT, OLS-35, etc., also have lasers for WVR combat.
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We can say "paired" when they share FoV; in case of Turkish aircraft, it just isn't the case(apart from narrow lense of shared sectors directly ahead) , though you can "pass" engagement from one sensor to another.
Still, this way one is a dedicated a2a sensor, one is primarily a2g/lookdown sensor. Su-75 was meant to be the same, but with EODAS/EOTS on - is it really absolutely needed?
P.s. Pirate doesn't have laser, that's the point(largest possible 8-12 mirror). I don't know about Karat, but overall it's consistent: MWIR+laser rangefinder, or LWIR alone.
snne said:
Are we looking at the same aircraft? Everything about the Su-57 screams "offensive aircraft" to me, except for the fact that the 101KS-V is essentially a further evolution of the OLS family.
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Offensive aircraft is meant to penetrate enemy airspace.
Su-57 doesn't, it's either a sensor node, or stand off PGM launcher.
It's telling that it's stand in a2g sensor is meant for permissive airspace only, and there's literally one integrated stand-in weapon (kab-250). Without little suns, su-57 can induce costs, but it won't be tearing apart IADS close and personal.
snne said:
Although both the Su-57 and the Su-75 are clearly offensive aircraft, the -75 is meant to operate right where the action is due to its lower signature, while the Su-57 stays further back and commands everything it’s capable of. This means the -75 needs to ambush other LO aircraft without revealing its position, or else it’d be a death sentence for it or could not reliably get a mission kill.
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You can still do it via cooperative engagement datalink, EODAS, EOTS, or LPI. Same as F-35...
Forest Green said:
So same evidence as R-37 shoot-downs then?
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Tbf, usually yes. Until someone will get to dig after the war, normal practice is either unmistakable debris/video or admission from engaged side.
In this case, our footage is a burned spot roughly corresponding to drone debris.
 
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@Ainen Let's keep it short, it seems we’re not quite reaching a resolution here :) I’ve noticed that most of our differences come down to how we define a subject, even though we’re often talking about the same scenarios in different ways.

source.gif
 

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Again, I still see zero "aircraft struck" especially if we are talking of burned composites. Even if it (they) was (were) damaged by fragments, not burned, it (they) could fly away from the base.
 
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Okay, top left inset is indeterminate since there is no before comparison, raising the question of why they included it.

EDIT: Okay, now I get it. The Su-34 in the middle (17/04) was moved to position in left inset, which presumably is an out of action spot. And the Su-57 in the left inset was also moved to the out of action spot in the top left. Or is it that the two Su-57s in the lower left inset were both moved to the top left?? Maybe, given the arrows.
 

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To end this false story. Only one Su-57 ( prototype or serial/operational ,nevermind) ,was damaged so far but little by the fragments of two exploded Ukr. drones as we can see on the photos. It is publicly known and it happened as we know on 8 June 2024 at Akhtubinsk air base. Not two as it was mentioned but one.

https://militarnyi.com/en/news/russ...the-art-su-57-fighter-jets-by-ukrainian-uavs/

On the other side ,war propaganda just like that from several days ago is sometimes a miracle especially during the hard time.Even today after 27 years ,there is some people in Serbia and Bosnia who really believe that YuAF light bombers like J-22 Orao and some trainers like G-4 Supergaleb really attacked airfields in Dubrave near Tuzla in Bosnia and Rinas near Tirana in Albania where some NATO assets were positioned during the NATO intervention on FRY. Of course, that never happened but story is story nevermind it is false or true.
 
What could even be the source of this image, is there a drone over the airbase? because that's not a sattelite image, in this case one would expect a video right? a still image suspiciously sharpened and cropped in that looks a lot like AI, again certified BS
 

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@Lepespi

Not only that but take a look to the space between those two white circles before and after the ''attack''.First we can see two Su-57's as marked between them and than there is wreckage from only one. What happened with another?

As I wrote ,story is story ....
 
Lepespi said:
What could even be the source of this image, is there a drone over the airbase? because that's not a sattelite image, in this case one would expect a video right? a still image suspiciously sharpened and cropped in that looks a lot like AI, again certified BS
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It's absent in official SBS video https://t.me/usf_army/1865
I don't understand why post endless retellings from 'OSINT sources' when you just can point to original
 
Yellowflash said:
Can someone be kind enough to explain why Su57 didnt go with a faceted IRST dome and instead used a semi-spherical one? what are the design trade off for both?
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Spherical is simpler, field of view great and they could reuse existing technology and solutions for it.
Faceted needs more effort and is only relevant when the rest of the airframe is sufficiently low RCS that the IRST sensor is a major contributor.
 
flateric said:
It's absent in official SBS video https://t.me/usf_army/1865
I don't understand why post endless retellings from 'OSINT sources' when you just can point to original
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Yes, a bajillion X "OSINT" accounts reposting stories with added bullshit. Lets try to stick to the real sources not the talking heads.
 
Squirrel said:
There is no bad weather conditions in the stratosphere ( 15-20+km).
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True, but also fighter doesn’t usually cruise that high against enemy with strong IADS, because plane are very sluggish up high. Additionally, you often need to dive down to dodge enemy AAM/SAM, so after the first shot, the follow through shot are often done at much lower altitude. It often something like: detect enemy => climb => shot the first shot => crank and dive down to dodge enemy return fire => climb again=> shot again.
 
Ronny said:
True, but also fighter doesn’t usually cruise that high against enemy with strong IADS, because plane are very sluggish up high. Additionally, you often need to dive down to dodge enemy AAM/SAM, so after the first shot, the follow through shot are often done at much lower altitude. It often something like: detect enemy => climb => shot the first shot => crank and dive down to dodge enemy return fire => climb again=> shot again.
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We can see that Su-35S ,Su-30SM/SM2 patrol/cruise at height 10-12km. What is the long range cruise/patrol height for the Su-57, we don't know. Keep in mind that MiG-31BM can patrol and cruise in the supersonic mode at 20+km. If you want to establish air superiority/air dominance, I think you must be 'higher' than the enemy.

If we talk about Su-57 in comparison with the FFF ( Flanker Family Fighters) in that domain, cruising,patrolling or maneuvering in higher stratosphere,that fighter has better possibilities, capabilities all in all.
 
isn’t that the f-22 profile? Fly at 13,000 m super cruising? I imagine the su-57 and mig-31 do that.
 
Squirrel said:
We can see that Su-35S ,Su-30SM/SM2 patrol/cruise at height 10-12km. What is the long range cruise/patrol height for the Su-57, we don't know. Keep in mind that MiG-31BM can patrol and cruise in the supersonic mode at 20+km. If you want to establish air superiority/air dominance, I think you must be 'higher' than the enemy.

If we talk about Su-57 in comparison with the FFF ( Flanker Family Fighters) in that domain, cruising, patrolling or maneuvering in higher stratosphere,that fighter has better possibilities, capabilities all in all.
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10-12 km is good altitude to cruise for most fighter jet since you have good enough height for your missile to fly far, yet still low enough so that you can have good chance of dodging enemy missile launching at you (by cranking and diving down).
Mig-31 can patrol at 20+ km, but its main role is to intercept bomber/cruiser missiles ie things that doesn't shot back, so it should fly as high as possible to maximizes the kinematic envelope of its missiles, enhancing engagement range.
However, this extremely high altitude profile also increases vulnerability, if a long range AAM (let say AIM-174, PL-17, R-37 or AIM-260) launched at you, they will have better chance of hitting the Mig-31 cruising at 20 km than the cranking Su-35 at 12 km
 
Ronny said:
10-12 km is good altitude to cruise for most fighter jet since you have good enough height for your missile to fly far, yet still low enough so that you can have good chance of dodging enemy missile launching at you (by cranking and diving down).
Mig-31 can patrol at 20+ km, but its main role is to intercept bomber/cruiser missiles ie things that doesn't shot back, so it should fly as high as possible to maximizes the kinematic envelope of its missiles, enhancing engagement range.
However, this extremely high altitude profile also increases vulnerability, if a long range AAM (let say AIM-174, PL-17, R-37 or AIM-260) launched at you, they will have better chance of hitting the Mig-31 cruising at 20 km than the cranking Su-35 at 12 km
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About MiG-31BM, there are two combat patrol/cruise modes: subsonic ,M 0.85 at about 10km for engaging e.g. low flying CM's ( it is impossible to do that from 20+km) and other valuable targets.Than supersonic ,M 2.35 at about 20km for engaging bigger, mostly non-maneuvering target from the max possible distances.As we could see,MiG-31BM with its long range R-37M is capable to engage even highly maneuvering targets.

About Su-57 ,is definitely capable to patrol/cruise ( in supercruise mode) at heights 10-20 km and with other FFF to cover that patrol zone.With AWACS assets and data-linked all together, it will be very hard for someone to engage e.g. MiG-31BM which will be the 'highest' ones.

Forest Green said:
So same evidence as R-37 shoot-downs then?
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In the case of the R-37M shot downs,we have in almost all cases the names of Ukr pilots being shot down,launch ranges data,UkrAF Command confirmation,type of VKS fighter which launched that long range AAM's etc...
 
His Majesty the King of Malaysia Sultan Ibrahim (the Sultan of Malaysia) has agreed to witness a demonstration of the fifth-generation multi-role fighter jet, the Sukhoi Su-57E, at Zhukovsky International Airport, Moscow today 8 May 2026 https://www.facebook.com/share/p/1GUJgWM8iS/
 

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^

Before him ,Commander of the RMAF had the chance to ''inspect'' the Su-57E.

''Royal Malaysian Air Force (RMAF) chief General Datuk Seri Muhamad Norazlan Aris got up close with Russia’s Sukhoi Su-57 fifth-generation fighter and other future air defence technologies at the Dubai Airshow 2025 in the United Arab Emirates (UAE).. — PIC FROM TENTERA UDARA DIRAJA MALAYSIA’S FB''
 

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Shaft3051 said:
I have heard from Engineers that it will be plug and play. So its designed with a modular architecture to house the AL-51F-1/Izdeliya 30 engine as soon as it is available, with the Al-41F-1 acting as a place holder till than, this is so that production and industry can mature around the available platform and hence the project isn't tied to engines which can be complex and tedious to develop and are usually subject to delays.
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The izdeliye 30 (AL-51F-1) was designed to be a drop-in replacement for the AL-41F-1 (izdeliye 117), and production Su-57s (the so-called second stage T-50 design with the reworked internal structure) were to be able to accommodate it. Note that the "second stage" T-50 is separate from the "Su-57M" project (Megalopolis) which would incorporate improved mission systems as well. "Second stage" needs clarification when discussing the Su-57 because depending on the context, it can refer to the airframe, or the engine, or an overall PAK FA modernization program.

More recently though, the izdeliye 177 has been pitched for re-engine of the domestic Su-57 as well, not just the export variant.
https://rostec.ru/media/news/energiya-poleta-80-let-okb-imeni-lyulki/

It's possible that this is viewed as more practical and economical than the izdeliye 30, especially given that the progress on this program has not exactly been quick or smooth. Even back in 2019-2020, Piotr Butowski in his book discussed the "Udlinitel" as a fallback in case the izdeliye 30 runs into problems. The 177 appears to incorporate an izdeliye 30-derived fan with the hot section ("gas generator") derived from the 117, and also likely a drop-in replacement. The rectangular nozzle appears to be engine-agnostic.
 

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