Sukhoi Su-57 flight testing, development & operations [2012-current]

[Ainen]

Another thing is, PAK-FA/Su-57 is meant to be a "complex", likely Russians use it as a starting platform for introducing 5th gen fighter technology. While Mach 3 intake isn't useful for Su-57, it's useful risk reduction for future applications and research on this done by TsAGI can likely be applied to something like PAK-DP interceptor, where for it's specific mission the lowest possible RCS isn't as important.

No one, ever, does things like this.

 

[overscan (PaulMM)]

Apologies for digging this up, it's just that I've always found the intake design & that of the radar blocker on The Su-57 to be rather strange, as it looks like they essentially tried to corkscrew their way out of the problem by opting for two weapons bays (that, of course, also created other issues) instead of a single one with S-Ducts by installing bizarre "partial S-Ducts" with a radar blocker & then people wonder as to why the speed of the aircraft is less than advertised, I guess, when the reason(s) should be obvious in that the blocker & inlet design combine to strangle the engine, lol, smh, not to mention the fact that "partial S-Ducts" are also pretty complex & expensive.

This is wild speculation on your part based on nothing but your own imagination, but I guess that's the name of the game now. Everyone's opinion is valid, facts and experts are overrated.

 

[RadicalDisconnect]

This is wild speculation on your part based on nothing but your own imagination, but I guess that's the name of the game now. Everyone's opinion is valid, facts and experts are overrated.

Yes, in terms of pure aero performance Su-57 intakes are perfectly fine and not the thing that limits top speed, that is more the materials and RAM coating. The issue is more the intake is unnecessary complex and optimize for speed beyond what Su-57 flies, and moving parts adds to maintenance. So in Su-75, Sukhoi went with a DSI type intake and in patent highlighted advantages. That said with Sukhoi and MiG consolidated under UAC, potentially Su-57 intake can find useful application in PAK-DP.

No one, ever, does things like this.

Considering Sukhoi and MiG are consolidated under UAC and MiG is developing PAK-DP, the experience and data from Su-57 intake can absolutely be useful here.

 

[Ainen]

Considering Sukhoi and MiG are consolidated under UAC and MiG is developing PAK-DP, the experience and data from Su-57 intake can absolutely be useful here.

So they'll screw up key national security project, meant for serial production, directly impacting its main specs, as a research stand for the future?
It isn't just laundering, that's called treason, onii chan. Cinema level one.

 

[flateric]

Sorry but should there be a debate again about which engine with new flat nozzle is in the left engine nacelle of the T-50-2LL? Marchukov said on June 2023 Samara's conference that 6th gen three-stream adaptive cycle engine was developed on the basis of the AL-41F-1. Started static tests on 2021. .

You are living in your pony world.

 

[Joint Soviet Fighter]

This is wild speculation on your part based on nothing but your own imagination, but I guess that's the name of the game now. Everyone's opinion is valid, facts and experts are overrated.

Uh...no - not even close, but please do continue, albeit hopefully without the established level of condescension.

 

[RadicalDisconnect]

Uh...no - not even close, but please do continue, albeit hopefully without the established level of condescension.

But your implication that the intake system of partial s-duct and radar blocker being limiting speed for Su-57 speed is wrong. In terms of aero performance the intake is completely fine, the blocker will have some loss but definitely not significant enough to be limiting speed, since variable ramps give excellent aero performance. The real speed limits come from materials especially PMC composites which Sukhoi themselves said in the past.

Also the intake system isn’t as good for RCS as a fixed intake which Sukhoi use for Su-75, but that has nothing to do with aero performance or speed limits.

So they'll screw up key national security project, meant for serial production, directly impacting its main specs, as a research stand for the future? It isn't just laundering, that's called treason, onii chan. Cinema level one.

Never said they intentionally tried to screw with things. The T-50/Su-57 complex variable intakes may have been deemed needed for original Mach 2.35 top speed, and it's not uncommon for desire to share technology, research, or components across different designs to increase commonality and reduce costs.

 

[Joint Soviet Fighter]

As far as top speed, intake radar blocker isn't the issue. Yes a blocker has some losses but they're not huge, and most important for high speed flight is intake pressure recovery, which with variable ramps the Su-57 intakes have no problems with that. So intakes are perfectly fine for Mach 2+, it's materials (especially composites) and RAM that is limiting factor, especially if reducing titanium and BMI usage because of cost. Compared to Su-27, the Su-57 use a lot less titanium and more composites. Sukhoi tried to use Al-Li alloy (VIAM 1461 alloy specifically) with better strength/weight ratio in place of B-95 alloy to reduce weight, but wasn't entirely successful.

Another thing is, PAK-FA/Su-57 is meant to be a "complex", likely Russians use it as a starting platform for introducing 5th gen fighter technology. While Mach 3 intake isn't useful for Su-57, it's useful risk reduction for future applications and research on this done by TsAGI can likely be applied to something like PAK-DP interceptor, where for it's specific mission the lowest possible RCS isn't as important.

Also not every innovation or technology is necessarily useful for future applications. For example F-35 style EHAs while being very precise and powerful may not be useful in future fighters because of how much electrical power they require and how much heat they generate.

That honestly makes The Su-57 sound like more of a flying laboratory than anything else, so...not great, Bob.

As for the intakes, I will defer to your expertise, it's just that, on the whole, would you consider the performance of the blocker & partial S-Ducts to be worth the cost, especially when you also factor in the complex assembly of the intakes? Personally, I don't.

 

[_Del_]

This conversation is all the wilder because to believe this one has to assume the Russians aren't smart enough to try to use their blocker like a stator and actually increase efficiency for the compressor.

 

[Joint Soviet Fighter]

But your implication that the intake system of partial s-duct and radar blocker being limiting speed for Su-57 speed is wrong. In terms of aero performance the intake is completely fine, the blocker will have some loss but definitely not significant enough to be limiting speed, since variable ramps give excellent aero performance. The real speed limits come from materials especially PMC composites which Sukhoi themselves said in the past.

Also the intake system isn’t as good for RCS as a fixed intake which Sukhoi use for Su-75, but that has nothing to do with aero performance or speed limits.

I stand corrected, then . Not exactly the best combination, though, is it, as you allude to in your last.

 

[Joint Soviet Fighter]

This conversation is all the wilder because to believe this one has to assume the Russians aren't smart enough to try to use their blocker like a stator and actually increase efficiency for the compressor.

I just don't think that they made the right decision in terms of rcs reduction measures *shrugs*.

 

[RadicalDisconnect]

This conversation is all the wilder because to believe this one has to assume the Russians aren't smart enough to try to use their blocker like a stator and actually increase efficiency for the compressor.

The blocker device is clearly separate from the IGV though, and we have a decent idea of the shape from both patents and pictures, which is a series of concentric rings that act as a radio wave trap and is canted and with length/diameter of about 1, and located at 0.7-1.2 times the duct diameter in front of IGV. So clearly do not have IGV or stator function which pre-spins the flow.

Many years ago I even asked here if an IGV can serve as radar blocker and the general consensus is no because of very different shaping requirements. Clearly a blocker will have some loss, but how it compares to full s-duct intake in performance is something you can’t know by just looking at it.

Su-57 design made the conscious decision to go with this intake design because of their desire for a large internal payload, achieved by using the space between the engines.

As for the intakes, I will defer to your expertise, it's just that, on the whole, would you consider the performance of the blocker & partial S-Ducts to be worth the cost, especially when you also factor in the complex assembly of the intakes? Personally, I don't.

You can’t look at the intake design in a vacuum. Overall up to Mach 2 the intake design is fine and competitive with S-duct, although more complex with moving parts and not as ideal for RCS. But with a straighter duct the Su-57 is able to have usable space between the engines for payload which was the intent of the design. Sukhoi specifically went this path to have large internal payload of 4 large 700kg cruise missiles, a lot more than F-22, F-35, or J-20 weapon bay arrangement.

So it’s a tradeoff and compromise of different desired characteristics in the end, like all aircraft designs.

 

[Joint Soviet Fighter]

You can’t look at the intake design in a vacuum. Overall up to Mach 2 the intake design is fine and competitive with S-duct, although more complex with moving parts and not as ideal for RCS. But with a straighter duct the Su-57 is able to have usable space between the engines for payload which was the intent of the design. Sukhoi specifically went this path to have large internal payload of 4 large 700kg cruise missiles, a lot more than F-22, F-35, or J-20 weapon bay arrangement.

So it’s a tradeoff and compromise of different desired characteristics in the end, like all aircraft designs.

It would seem that the only way to answer this, then, would be to somehow determine the effectiveness in terms of rcs reduction of a straight intake that makes use of a shock cone/pyramidal device & a radar blocker as opposed to the arrangement in The Su-57 &, of course, the traditional S-Duct alignment, as I agree with your point about the space between the engines, although that raises another question.

Obviously, as you said, all aircraft (& tank, etc.,) designs are compromises, so if the straight duct with a cone/whatever & a radar blocker somehow actually performs better than the current configuration & they were to then also smooth the underside, would it not to be possible to store, idk, another two bombs/missiles in the now single weapons bay? The payload won't be exactly the same, of course, but getting rid of the second weapons bay in order to reinforce the overall structure while also improving the rcs makes much more sense to me, but I'm an idiot, so...yeah. Everything really hinges on the comparison between the intake designs. I'm sure that the traditional S-Duct will still prevail over my "arrangement", but how substantial is that difference, as if it's manageable, much cheaper to build, & easier to maintain, then the choice should be obvious. I think.

Meh, Sukhoi didn't want to alter the design for India, iirc, so I can't imagine that they would suddenly radically alter it, now.

 

[RadicalDisconnect]

Obviously, as you said, all aircraft (& tank, etc.,) designs are compromises, so if the straight duct with a cone/whatever & a radar blocker somehow actually performs better than the current configuration & they were to then also smooth the underside, would it not to be possible to store, idk, another two bombs/missiles in the now single weapons bay? The payload won't be exactly the same, of course, but getting rid of the second weapons bay in order to reinforce the overall structure while also improving the rcs makes much more sense to me, but I'm an idiot, so...yeah. Everything really hinges on the comparison between the intake designs. I'm sure that the traditional S-Duct will still prevail over my "arrangement", but how substantial is that difference, as if it's manageable, much cheaper to build, & easier to maintain, then the choice should be obvious. I think.

I'm not seeing the point to this. Something that sounds "better" on paper needs to be fully analyzed and tested. If current design meets Russian MoD requirements then there's not much point in doing all this work, and then needing to retest everything. And even then, Sukhoi does not seem very willing to change much of vehicle design, like when asking for flat nozzle, they won't reshape the nacelle and instead make Saturn design the nozzle around it as drop in. Maybe not ideal for RCS but there are cost benefits to this.

And right now this is a lot of speculation and "what ifs" but at some point it's just spilt milk under the bridge.

 

[Squirrel]

The blocker device is clearly separate from the IGV though, and we have a decent idea of the shape from both patents and pictures, which is a series of concentric rings that act as a radio wave trap and is canted and with length/diameter of about 1, and located at 0.7-1.2 times the duct diameter in front of IGV. So clearly do not have IGV or stator function which pre-spins the flow.

Many years ago I even asked here if an IGV can serve as radar blocker and the general consensus is no because of very different shaping requirements. Clearly a blocker will have some loss, but how it compares to full s-duct intake in performance is something you can’t know by just looking at it.

Su-57 design made the conscious decision to go with this intake design because of their desire for a large internal payload, achieved by using the space between the engines.


You can’t look at the intake design in a vacuum. Overall up to Mach 2 the intake design is fine and competitive with S-duct, although more complex with moving parts and not as ideal for RCS. But with a straighter duct the Su-57 is able to have usable space between the engines for payload which was the intent of the design. Sukhoi specifically went this path to have large internal payload of 4 large 700kg cruise missiles, a lot more than F-22, F-35, or J-20 weapon bay arrangement.

So it’s a tradeoff and compromise of different desired characteristics in the end, like all aircraft designs.

If you mean at this pic ...

https://twitter.com/x/status/1335664131538640896

View: https://x.com/SlavaTheThird/status/1335664131538640896

Let's Talk About The Su-57 And The Radar Blockers Allegedly Sighted For The First Time Inside The Felon's Air Intake

The Su-57 Felon's radar blockers were allegedly exposed by a video part of a longer feature aired by Russian television for the centenary of the Chkalov

theaviationist.com

This was nothing but Photoshop.

''В декабре 2020 года в одном из Телеграм-каналов было показано изображение воздухозаборника опытного самолёта Су-57, полученное копированием экрана во время одной из передач Первого канала ТВ. При обработке снимка из этого видео средствами графического редактора Photoshop, становится отчётлива видна коаксиально-радиальная решётка, которая очень схожа с описанием в патенте RU 2623031.''

There is no evidence yet that serial Su-57's have that coaxial-radial grids /radar blockers.New, so called second-stage engine AL-51F has beveled IGV.

 

[paralay]

Did you hear the sound of the Su-57?

 

[flateric]

If you mean at this pic ...

https://twitter.com/x/status/1335664131538640896

View: https://x.com/SlavaTheThird/status/1335664131538640896

Let's Talk About The Su-57 And The Radar Blockers Allegedly Sighted For The First Time Inside The Felon's Air Intake

The Su-57 Felon's radar blockers were allegedly exposed by a video part of a longer feature aired by Russian television for the centenary of the Chkalov

theaviationist.com

This was nothing but Photoshop.

Sure!

 

[LMFS]

The issue is more the intake is unnecessary complex and optimize for speed beyond what Su-57 flies, and moving parts adds to maintenance. So in Su-75, Sukhoi went with a DSI type intake and in patent highlighted advantages.

LTS is a numbers plane, where Su-57 is an air superiority platform. The queen on the board, in words of Strelets when comparing both during the presentation of the "Chekmate". So, performance-wise those two don't necessarily need to be on the same level, specially in regards of speed, for instance, where basic TWR estimations and other design decision like the intake type you mention can already give a clear hint. On top of that, no one really knows the top speed of Su-57 or what level of damage to the coatings could be acceptable depending on the mission, if that was actually an issue. Nobody wastes the time, money and effort in designing those variable intakes if not for a clear and justified reason.

 

[Deino]

If you mean at this pic ...

https://twitter.com/x/status/1335664131538640896

View: https://x.com/SlavaTheThird/status/1335664131538640896

Let's Talk About The Su-57 And The Radar Blockers Allegedly Sighted For The First Time Inside The Felon's Air Intake

The Su-57 Felon's radar blockers were allegedly exposed by a video part of a longer feature aired by Russian television for the centenary of the Chkalov

theaviationist.com

This was nothing but Photoshop.

''В декабре 2020 года в одном из Телеграм-каналов было показано изображение воздухозаборника опытного самолёта Су-57, полученное копированием экрана во время одной из передач Первого канала ТВ. При обработке снимка из этого видео средствами графического редактора Photoshop, становится отчётлива видна коаксиально-радиальная решётка, которая очень схожа с описанием в патенте RU 2623031.''

There is no evidence yet that serial Su-57's have that coaxial-radial grids /radar blockers.New, so called second-stage engine AL-51F has beveled IGV.

Not sure what BS you are talking about! It was no photoshop! Just take the original image on your own and change the contrast/colour-settings and you will see exactly the same!

 

[AGS-1787]

If you use the twitter post you won’t see it since the image is low resolution, this is image is from the video screenshot. I changed the shadow settings and contrast; this is the result

 

[Joint Soviet Fighter]

I'm not seeing the point to this. Something that sounds "better" on paper needs to be fully analyzed and tested. If current design meets Russian MoD requirements then there's not much point in doing all this work, and then needing to retest everything. And even then, Sukhoi does not seem very willing to change much of vehicle design, like when asking for flat nozzle, they won't reshape the nacelle and instead make Saturn design the nozzle around it as drop in. Maybe not ideal for RCS but there are cost benefits to this.

And right now this is a lot of speculation and "what ifs" but at some point it's just spilt milk under the bridge.

I was just trying to improve the overall performance of the plane while also saving money & reducing assembly/manufacturing complexity, but as you said, it's a moot point, as Sukhoi isn't going to alter much of anything, so I'll shut up, now, lol, smh.

 

[Joint Soviet Fighter]

LTS is a numbers plane, where Su-57 is an air superiority platform. The queen on the board, in words of Strelets when comparing both during the presentation of the "Chekmate". So, performance-wise those two don't necessarily need to be on the same level, specially in regards of speed, for instance, where basic TWR estimations and other design decision like the intake type you mention can already give a clear hint. On top of that, no one really knows the top speed of Su-57 or what level of damage to the coatings could be acceptable depending on the mission, if that was actually an issue. Nobody wastes the time, money and effort in designing those variable intakes if not for a clear and justified reason.

While I actually like the design of The Su-75 aside from the irst bulb (keeping the v-tail would have been better, too, imo), The Checkmate isn't "a numbers plane" until it's actually built in significant quantity.

As for The Su-57, it has some really cool features, but its overall design makes for a rather disappointing rcs while also lacking the same kind of necessary defensive systems/sensors on The F-35 (DAS & EOTS), so I wouldn't exactly call it "an air superiority platform", at this point. Russia has the ability to make a much better plane, especially given that their optics industry has exploded, but idk about the overall priorities/requirements for their air force other than the current ones that seem to be seriously outdated.

As of right now, though, I would actually take The Felon over The F-22 in a dogfight (that will likely never happen outside of DCS), if that means anything.

 

[yeetmahboi]

I was just trying to improve the overall performance of the plane while also saving money & reducing assembly/manufacturing complexity, but as you said, it's a moot point, as Sukhoi isn't going to alter much of anything, so I'll shut up, now, lol, smh.

There are better places for speculating than this forum. I dare not take on the mantel of a moderator but I implore members to moderate their own output. Otherwise, there is a special sub-section for fanarts and speculation.

 

[Deino]

There are better places for speculating than this forum. I dare not take on the mantel of a moderator but I implore members to moderate their own output. Otherwise, there is a special sub-section for fanarts and speculation.

I would like to call it the "Kindergarten-Section" best!

 

[Squirrel]

Did you hear the sound of the Su-57?

First this, the sound of the Su-57 that we can sometimes hear has nothing to do with that 'radar blockers' if they really exist inside of the air intakes of the Su-57's.

View: https://www.youtube.com/watch?v=Zid1Nv-FfyQ

View: https://www.youtube.com/watch?v=1Fb9tvyPqEU&t=4s


That 'sound phenomena' is more related to the nozzles and engine compressor.You can find many videos with that specific sound where we can see much older fighters then Su-57 itself.

For others ,about that so called coaxial-radial grid or radar blocker. We have for now only one photo, very suspicious and questionable photo. One Russian source ( not some western) ,wrote that it was Photoshop.

Стелс-технологии Су-57 - приоритет передней полусфере » Авиация России

Видимость современного истребителя в радиолокационном поле характеризуется величиной эффективной поверхности рассеяния (ЭПР) - одной из характеристик, которая

aviation21.ru

Photoshop or not, that is not the main issue.The main issue ( problem) is, where is the real place for the real radar blocker inside of the air intakes. As we know from the Patent and some other sources ,that radar blockers must be inside of the air intakes,not inside of the engine necelles ( logical of course). Now if I may ,I will analize some details about that.
First we must know that coaxial-radial grid is not so narrow and has some width. As we can see ,it is part of the air intake and is positioned in front of the IGV ( on the Russian it is 'BHA'). This is very important :

''Решетка в канале может быть установлена таким образом, что расстояние по продольной оси воздушного канала от решетки до входного направляющего аппарата (ВНА) двигателя составляет от 0,7 до 1,2 диаметра d воздушного канала.''

Transl :

''The grid in the channel can be installed in such a way that the distance along the longitudinal axis of the air channel from the grid to the inlet guide vane (IVA) of the engine is from 0.7 to 1.2 times the diameter d of the air channel.''

ИЗ №2623031

www1.fips.ru

Sukhoi Su-57 in colours (PAK FA, Prospective Frontline Aviation System). Sukhoi Su-57 fighter camouflage and painting schemes. Prototypes and serial production, deliveries, units, numbers. S-70 Okhotnik unmanned aerial vehicle. Russian Air Force.

Now some questions :

1. Where can be the real place for that grid/radar blocker inside of this air intake?



2. As we can see on this photo,we have air intake and engine nacelle joined together but where is the real place for the radar blocker? We can only see the place /ring where IGV will be attached/positioned.



3. Again ,air intake and engine nacelle joined together. Where is the radar blocker ? ( photo from 2020).




4. Same detail,red arrow shows us the place where air intake made from Al Alloy is joint with the engine nacelle made from Ti Alloy.Where can be the real place for the real radar blocker there ? I can not see that place.



5.Again, the air intake and we cannot see any radar blocker inside of it.



One of the issues/problems when we talk about the radar blocker inside of the air intake is ,what about the air mass flow ?

Now ,if someone can find the real place for the real radar blocker inside of those air intakes, I would be glad to see that and to make together some good analysis.

 

[AGS-1787]

Well we could take a screenshot of the video used to get the photo. To me the photo looks real, the way the pixels look when changing contrasts looks unmolested. That could end the discussion. The Russians have a patent; why wouldn’t they apply it?

 

[AGS-1787]

There you go, I found a video where they talked about the aircraft, took a screenshot, and changed the shadows/highlights. It does have a blocker.

 

[AGS-1787]

Plus a canted engine and variable intake and a slight s curved intake so…

 

[Dr.Snufflebug]

Earlier pics of the intakes from the front with brightness blown up like this show the actual engine fan/compressor face, it looks quite different.

AFAIK the distinct screeching sound is notably absent in the first bunch of T-50s, it appeared at the same time as that interesting intake contraption was first spotted. So there's that.

And lastly, if I am not mistaken, there are actually patent drawings of a blocker that fully match the appearance of this contraption.

 

[AGS-1787]

Yep I took this straight from a video; the aircraft shown seems to be a serial aircraft. So there you have it.

 

[FlyGuy369]

This link shows a little bit about it, albeit I don't know the source's credibility.

Su-57 Radar scattering simulation

Introduction Su-57 is the first aircraft in Russian military service designed with stealth technology, it is intended to replace Su-27/30/35 family and server as the Russian answer to the American …

basicsaboutaerodynamicsandavionics.wordpress.com

 

[Squirrel]

Well we could take a screenshot of the video used to get the photo. To me the photo looks real, the way the pixels look when changing contrasts looks unmolested. That could end the discussion. The Russians have a patent; why wouldn’t they apply it?

On that photo is the prototype. Where is the radar blocker inside of the air intakes of the serial Su-57's ?

 

[Tomboy]

This link shows a little bit about it, albeit I don't know the source's credibility.

Su-57 Radar scattering simulation

Introduction Su-57 is the first aircraft in Russian military service designed with stealth technology, it is intended to replace Su-27/30/35 family and server as the Russian answer to the American …

basicsaboutaerodynamicsandavionics.wordpress.com

I'm pretty sure that is made in collab with @stealthflanker, who is a radar expert and does some very good sims here.

 

[flateric]

'I don't see classified radar blocker on cleared assembly video and photos, hence it's absent'
80 lvl logic

 

[flateric]

For others ,about that so called coaxial-radial grid or radar blocker. We have for now only one photo, very suspicious and questionable photo. One Russian source ( not some western) ,wrote that it was Photoshop.

This is not a "very suspicious photo" but screenshot from GLITz anniversary video. It's interesting that you give link to the original Twitter post that has both link to _original video_ and description of actions author made to inlet screenshot to rise lightning level using _Photoshop_, but even didn't care to use Twitter translate to understand that.
'Aah, Photoshop, familiar word. It's PSed then, period.'

 

[SlowHandClap]

As of right now, though, I would actually take The Felon over The F-22 in a dogfight (that will likely never happen outside of DCS), if that means anything.

Based on what circumstances? Because I feel like the Raptor trumps the Felon BVR & WVR purely from a weaponry perspective, and things don't get better for the felon when you factor in flight performance/dimensions.

 

[flateric]

Please don't start another "cool looking" vs. "not so cool looking" and sim battles round of useless posts comparing aircrafts and weapons which TO and specs will remain classified for a long.

 

[Joint Soviet Fighter]

I would like to call it the "Kindergarten-Section" best!

Thanks!

 

[Joint Soviet Fighter]

Based on what circumstances? Because I feel like the Raptor trumps the Felon BVR & WVR purely from a weaponry perspective, and things don't get better for the felon when you factor in flight performance/dimensions.

The lack of a helmet-mounted sight & irst on The Raptor are YUGE handicaps in a dogfight (I know, I know, it will never happen, blah, blah, blah).

 

[Joint Soviet Fighter]

On that photo is the prototype. Where is the radar blocker inside of the air intakes of the serial Su-57's?

The Su-57's radar blocker has been discussed on this forum for years.