Su-57 Felon

[wrightwing]

From Su-57 displayed on the ground at MAKS 2019. (I recently learned about this photo.)
Can the Su-57 not close the weapons bay exactly, properly!?

That's not even Chinese level fit/finish, much less approaching F-22/35 tolerances.

The Fit and Finish of the Chinese Stealth Fighters "appears" to be quite good....


J-20

J20FFQ.jpg

J-31

J31FFQ.jpg

That wasn't my point.

[milosh]

At best, the Su-57 is an LO design, and not even necessarily an all aspect one at that. There isn't enough RAM/RAS, radar blockers, or nozzle designs, that can change that. Not even the Russians have made such a ridiculous claim.

Can you point me to any statement for people working on Su-57 about its RCS?

http://www.scielo.br/pdf/jatm/v8n1/1984 ... 1-0040.pdf

We have study wrote by four leading Chinese aeronautic experts about shape:

The mean RCS value in a range
of ± 30° of the forward direction is −5.625 dBsm when exposed
to 10-GHz radar wave. In general, it is the same or even exceeds
the stealth level of modern fighters in the world.

No RAM and RAS applied. Both work quite well especially with X-band for RCS reduction.

So it is clearly VLO design, other question would Russians really build it to match VLO requirement.

[Corsair1963]

[wrightwing]

At best, the Su-57 is an LO design, and not even necessarily an all aspect one at that. There isn't enough RAM/RAS, radar blockers, or nozzle designs, that can change that. Not even the Russians have made such a ridiculous claim.

Can you point me to any statement for people working on Su-57 about its RCS?

http://www.scielo.br/pdf/jatm/v8n1/1984 ... 1-0040.pdf

We have study wrote by four leading Chinese aeronautic experts about shape:

The mean RCS value in a range
of ± 30° of the forward direction is −5.625 dBsm when exposed
to 10-GHz radar wave. In general, it is the same or even exceeds
the stealth level of modern fighters in the world.

No RAM and RAS applied. Both work quite well especially with X-band for RCS reduction.

So it is clearly VLO design, other question would Russians really build it to match VLO requirement.

I can point to statements by Russians working on the jet, stating frontal RCS of ~.5m^2, and by Indian sources who've complained about disappointing stealth levels. I haven't seen a single source ever mention all aspect VLO signature reduction. You're pulling that out of your backside.

[boogieman]

It seems the first production standard Su57 has crashed in Russia. Pilot is ok.

https://amp.businessinsider.com/russias ... es-2019-12

EDIT: NVM I see this has it's own thread.

[Corsair1963]

At best, the Su-57 is an LO design, and not even necessarily an all aspect one at that. There isn't enough RAM/RAS, radar blockers, or nozzle designs, that can change that. Not even the Russians have made such a ridiculous claim.

Can you point me to any statement for people working on Su-57 about its RCS?

http://www.scielo.br/pdf/jatm/v8n1/1984 ... 1-0040.pdf

We have study wrote by four leading Chinese aeronautic experts about shape:

The mean RCS value in a range
of ± 30° of the forward direction is −5.625 dBsm when exposed
to 10-GHz radar wave. In general, it is the same or even exceeds
the stealth level of modern fighters in the world.

No RAM and RAS applied. Both work quite well especially with X-band for RCS reduction.

So it is clearly VLO design, other question would Russians really build it to match VLO requirement.

I can point to statements by Russians working on the jet, stating frontal RCS of ~.5m^2, and by Indian sources who've complained about disappointing stealth levels. I haven't seen a single source ever mention all aspect VLO signature reduction. You're pulling that out of your backside.

Clearly, from all reports India was very unimpressed with the level of Stealth on the Su-57. Which, would explain why they have completely lost interest in the type. Even after repeated attempts by Russia to get them to reconsider. Which, personally speaks volumes to me....

[milosh]

Clearly, from all reports India was very unimpressed with the level of Stealth on the Su-57. Which, would explain why they have completely lost interest in the type. Even after repeated attempts by Russia to get them to reconsider. Which, personally speaks volumes to me....

And then you hear Indians praising Rafale as stealth fighter which would detect first Chinese stealths and down them much earlier then they detect Rafale becuase it is armed with Meteor missiles and this isn't some fanboys said this is what IAF commander said when he was asked why India don't get stealth when China have them, he said Rafale is stealth, have much better sensors and missiles!

@weightwing

0.5m2 is mean value of PAK-FA RCS, I think in patent average RCS is 0.1 to 1m2 so mean value is 0.5m2. Lowest frontal RCS by pantent is 0.1m2 highest is 1m2.

Real number is probable lower then what is written in patent, becuase no one would publicly declare RCS value. F-22 which is operational for almost two decades still have classifed RCS value and SR-71 also.

[wrightwing]

@weightwing

0.5m2 is mean value of PAK-FA RCS, I think in patent average RCS is 0.1 to 1m2 so mean value is 0.5m2. Lowest frontal RCS by pantent is 0.1m2 highest is 1m2.

Real number is probable lower then what is written in patent, becuase no one would publicly declare RCS value. F-22 which is operational for almost two decades still have classifed RCS value and SR-71 also.

The F-22's (and F-35's) RCS are classified, but.... the vanilla open source figures that have been given are frontal RCS in the .0001m^2 range. To even be considered VLO, the Su-57 would need to be down to .001m^2.

[milosh]

The F-22's (and F-35's) RCS are classified, but.... the vanilla open source figures that have been given are frontal RCS in the .0001m^2 range. To even be considered VLO, the Su-57 would need to be down to .001m^2.

Maybe but I think 0.01m2 would be quite good achievement, it would be problematic for non IRST equipped fighters.

[wrightwing]

The F-22's (and F-35's) RCS are classified, but.... the vanilla open source figures that have been given are frontal RCS in the .0001m^2 range. To even be considered VLO, the Su-57 would need to be down to .001m^2.

Maybe but I think 0.01m2 would be quite good achievement, it would be problematic for non IRST equipped fighters.

.01m^2 is considered LO, but it would still be a challenge for fighters with large RCS values. I've never seen any Russian claims for .01m^2, though.

[talkitron]

Russia has sold 14 Su-57s to Algeria as well as 14 Su-34s and 14 Su-35s. It seems like Russian exports have been down lately and the overall defense spending has decreased, hitting tactical aviation as nuclear weapons are the priority. So a sale of 42 jets is a big win for Russia. The Algerian decision is described in a way that makes it seem unprofessional to me.

https://www.menadefense.net/non-classe- ... 34-bomber/

The decision was taken in the summer of 2019 after the visit of an Algerian delegation to the MAKS air show in Moscow. During this visit led by the Air Force Commander Major General Boumaiza, the Su-57 was examined from every angle, the former Algerian Mig-29 pilot was even one of the rare foreigners to try the stealth plane Russian on a simulator. It is he who would have decided on the future of acquisitions of the air force after five years of procrastination and loss of time. The rise of the Moroccan Air Force with the acquisition of 25 F-16 Vipers and the appearance of F-35s in the Italian fleet motivated Algeria’s rapid decision-making.

[madrat]

Seems like Algeria is all over the spectrum. After the 2008 rejection of MiG-29 they were working France hard for Rafale. So were the Rafale dreams put to bed?

[marsavian]

At best, the Su-57 is an LO design, and not even necessarily an all aspect one at that. There isn't enough RAM/RAS, radar blockers, or nozzle designs, that can change that. Not even the Russians have made such a ridiculous claim.

Can you point me to any statement for people working on Su-57 about its RCS?

http://www.scielo.br/pdf/jatm/v8n1/1984 ... 1-0040.pdf

We have study wrote by four leading Chinese aeronautic experts about shape:

The mean RCS value in a range
of ± 30° of the forward direction is −5.625 dBsm when exposed
to 10-GHz radar wave. In general, it is the same or even exceeds
the stealth level of modern fighters in the world.

No RAM and RAS applied. Both work quite well especially with X-band for RCS reduction.

So it is clearly VLO design, other question would Russians really build it to match VLO requirement.

In the real world though the Su-57 Mk 1 engine has an open engine face with no RCS reduction apart from RAM which the similar Su-35 engine has. This will keep the frontal RCS relatively high and more like Typhoon/Rafale/Super Hornet/Gripen than F-22/F-35. The Su-57 is also not stealthy from the sides. Su-57 is a pretty poor implementation of a stealth fighter considering they had the working example of F-22 to base it on.

[boogieman]

In the real world though the Su-57 Mk 1 engine has an open engine face with no RCS reduction apart from RAM which the similar Su-35 engine has. This will keep the frontal RCS relatively high and more like Typhoon/Rafale/Super Hornet/Gripen than F-22/F-35. The Su-57 is also not stealthy from the sides. Su-57 is a pretty poor implementation of a stealth fighter considering they had the working example of F-22 to base it on.

I was under the impression that the Su57's engines were displaced so that the compressor face is obscured from the front (a design feature found on the YF23) and that RCS reducing shrouds were to be used on production models. Not going to place TOO much weight on this source but it explains what I am talking about:



Assuming the above is true, the biggest issue I can see with Su57 frontal RCS is the IRST bulb up front. Strikes me as a really bizarre design choice if you're trying to build a VLO jet.

[milosh]

I was under the impression that the Su57's engines were displaced so that the compressor face is obscured from the front (a design feature found on the YF23) and that RCS reducing shrouds were to be used on production models. Not going to place TOO much weight on this source but it explains what I am talking about:

https://www.youtube.com/watch?v=EPdKc2Ca610

Assuming the above is true, the biggest issue I can see with Su57 frontal RCS is the IRST bulb up front. Strikes me as a really bizarre design choice if you're trying to build a VLO jet.

No it isn't like YF-23 it is common mistake because Su-57 main gear is lower so plane is tilted down when on ground and then it look like engines are above intake mouths.

Su-57 intake is like X-32 in therms of stealth design (not stealthy at all):
http://www.aviationexplorer.com/boeing_ ... g_x-32.jpg

So if F-32 is stealth I really don't see why Su-57 isn't if we just talk about intake.

Of course both would need to use radar blocker but here is where Su-57 have "advantage" F-32 because of STOVL couldn't use complex blocker while Sukhoi radar blocker look fraking complex:
https://findpatent.ru/patent/262/2623031.html

It look like combination of couple of radar blockers, first some ring blocker, then mesh and then something similar to S.Hornet radar blocker.

OLS backside is composite with thick RAM so when it isn't in function its impact of RCS is small. When it is in function it increase RCS but not as folks like to calculate, they use metalic sphere as analog

@marsavian

Of course they did analyse lot of different designs, here are F-22 & F-23 combo:
https://naukatehnika.com/files/journal/ ... 47-e-6.jpg

But they decide to go with complex radar blocker. S-duct would reduce capability to carry four big missiles/bombs or two big missiles/bombs and four R-XY (short missile which replace R-77).