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Sukhoi Su-57 / T-50 / PAK FA - flight testing and development Part II [2012-current]

AGS-1787

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Interesting, 08 is still flying around with the partial RAM application?

283132.jpg
Is the orange stripe around the windshield some kind of test equipment? why would they still be testing on this section of the airplane if it is already in serial? Are they still testing the all-moving tails?
 

tequilashooter

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But you see this?
I see. And i read it as PASSIVe and active. And again, KNIRTI is not a developer of radars for PAK FA, NIIP is.

i was wrong either way because Igor stated the functions of a fundamentally new radar for the pafka, not the existing EW system. You know the front, sides and behind view quote? I dont even care anymore it gets other users here worked on what the su-57 has or will not have. The Voltaire quote,"I disapprove of what you say,but I will defend your right to the death to say it." Doesnt apply here. I will drop the subject.
 

TomcatViP

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View: https://twitter.com/i/status/1390535336539852802


 

Cannonfodder43

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At what point does the Radar Blockers being the cause of the noise become common knowledge? It's been known they make that noise now for a while.

It's truly both amusing and infuriating how uninformed people truly are about the Felon.
 

stealthflanker

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At what point does the Radar Blockers being the cause of the noise become common knowledge? It's been known they make that noise now for a while.

It's truly both amusing and infuriating how uninformed people truly are about the Felon.

At least it got people to click hahahaha.
-------------------


Anyway, something for fun. So yeah I did a little bit of experiment. I made myself a model of an inlet. With a simple Radar blocker and a compressor face with its respective Guide vanes.

Inlet and blockers.png

The radar blocker is just loosely based on the one in Su-57 patent. treatments that i did was to the leading edge of the Blocker where it would have ogival shaped edge to reduce contribution of RCS from the edge. The RAM Is the one from the "Radar Cross Section 2nd Edition" the Magnetic RAM Sintered-Zinc-Nickel-Ferrite.
The inlet Body is not treated and left as PEC, so does the engine face. The solution being used is SBR+ Which allows cavity RCS to be computed

The frequency being used here is L-band (1 GHz) because it's fast and can still enter the duct. Polarization is horizontal, and 3 conditions were taken as follows and the result in 2D contour projection :

No Radar BlockerBoth radar blocker and engine face are made out of
PEC (Perfect Electric Conductor)
Blocker is treated with Radar absorber
No Blocker.png Inlet and blockers.png Inlet and blockers.png
NoBlocker.png Inlet-blocker both PEC.png With Blocker.png
Remarks :
Relatively strong and broad reflections from the blades and guide vanes.
Remarks :
Blocker and Inlet are basically compounding each other, produces strong reflections at the middle of the engine face.​
Remarks :
The radar blocker appears to be able to suppress the reflection of the blades behind it, "flare spots" appears to be reduced.

The above projection are views from the front of the engine. Basically from this :

Face1-With Blocker.png

Numerical wise this is the Median of the inlet's RCS :
Blocker3 coloumns.png

There is about 5-6 dB or 3-4 times of RCS reduction from above model. Doesnt sound like alot but still reduction. Plus i have no idea on how actually a radar blocker is designed. I wonder what kind of reduction a purposely designed and optimized radar blocker can have.

The subject of the design of radar blocker however appears to be rare in open literature so far. There are patents, but research papers are somewhat nonexistent. There are instead many on S-duct. Even the idea of ogival leading edge treatment for my simple radar blocker there came from paper dealing with S-duct (Attached):
 

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tequilashooter

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Sweet is that a test result from a anechoic chamber or another guestimate like the south Korean 5th gen thread?
 

stealthflanker

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Sweet is that a test result from a anechoic chamber or another guestimate like the south Korean 5th gen thread?
Obviously Guesstimate with ANSYS.

note that the inlet, blockers are just loosely based. Not gonna claim that would be the real signature. As i said above i have no idea how the blocker was actually designed.
 

tequilashooter

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Obviously Guesstimate with ANSYS.

note that the inlet, blockers are just loosely based. Not gonna claim that would be the real signature. As i said above i have no idea how the blocker was actually designed.

main-qimg-85d7e99aaa000ff779069c4f010c2dc9.jpg
main-qimg-17167430ee43c9cdc8bc609e57fdeea3.jpg
Got source from LMFS https://findpatent.ru/img_show/12839574.html

  • There were partial S-ducts demonstrated on the patent itself. Meaning the fan blades are not completely exposed but partially.
  • RAM is applied in the inlet.
  • Patent and image shows radar blockers to reflect radio waves away from radar source and covering fan blades
  • There is an anti-radar grading installed inside the air channel.
  • Fan blades are made of composite materials
  • Image of inlet vanes along with patent which are behind the blades are seen as being designed a particular way to lower RCS on bottom image.
If you saw this patent before or not I don't know, just wondering if the above statements were taken into account of the model you made of the inlet? (I no you cant take in account the absorption properties of their RAM)
 

dannydale

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Sounds a bit like a howling F-104. Also, distinctive sounds make any weapon more badass!
 

stealthflanker

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Obviously Guesstimate with ANSYS.

note that the inlet, blockers are just loosely based. Not gonna claim that would be the real signature. As i said above i have no idea how the blocker was actually designed.




If you saw this patent before or not I don't know, just wondering if the above statements were taken into account of the model you made of the inlet? (I no you cant take in account the absorption properties of their RAM)

Well you should be able to see what i took into account in my post.


The only thing demonstrated from my observation above are that the blocker works. But it also opens up many question like how to optimize the shape. basically things you dont get from just the patent images. Or like why it shaped the way it is.
 

Trident

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Anyway, something for fun. So yeah I did a little bit of experiment. I made myself a model of an inlet. With a simple Radar blocker and a compressor face with its respective Guide vanes.

Interesting! Some suggestions if I may:

1) Your inlet shape seems to be square with right angles in frontal projection, this is not accurate. The real inlet is a rhomboid which will probably affect the location of spikes.

2) Your blocker & engine face appear to be too close to the intake opening, which will probably impact things as well (especially in connection with #3).

3) It would be nice to see what coating the interior walls of the intake duct ahead of the blocker with RAM changes.
 

tequilashooter

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doesn't the Super Hornet also use a similar blocker? and if so does it make a similar sound to the 57?
Only problem with other aircrafts carrying blockers (besides the Su-57) I cant find patents for or what physical features they carry in shape if they compare to the su-57.
 

TMA1

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Saw this on another forum. It's from the parade that happened recently. It's obviously CG and it could just be added by the company mistakenly or even maybe some intentional disinformation. Still interesting it was even added. Horizontal louvres in the intake. What do you guys think?
 

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TomcatViP

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@TMA1 : Good screenshot.
I think you are right: they are probably trying to offer a quick answer to those trying to understand from where the witheling noise comes from (I can't see how such error would have been left unnoticed by Mil officials).
Honestly, it's a good explanation since those kind of louvres will certainly produce such witheling noise in the airstream.

But then, according to our knowledge so far, they are not part of the real Su-57.
 
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tequilashooter

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This information was deleted so I wonder if it holds any significance, enjoy. https://webcache.googleusercontent....s/2021/5/18/228542/+&cd=1&hl=en&ct=clnk&gl=us

On May 18, 2021, AEX.RU - A. Lulka Design Bureau - a subsidiary of"ODK-UMPO"is working on the formation of a scientific and technical backbone to create a sixth-generation engine for combat aviation. "This is a three-contour scheme, which the whole world is doing," Evgeny Marchukov, general designer of the Design Bureau, said at the ICAM-2020 conference. This is reported by the press service of the MAKSAir Show.

According to him, two options for implementing this scheme are being developed. The first stand tests of the demonstrator are due to take place in 2021. Using a three-contour scheme will allow to modernize the al-41F-1engine, improving its characteristics while maintaining dimensions.

In addition, as part of the creation of the NTH OCB, I.A. Lulki is engaged in such areas as a combustion chamber with wave detonation, a pulsating resonative detonation engine with a two-stage burning of kerosene-air mixture.
 

TMA1

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Fascinating. Is that izd 30? Looks like it has the same cold air bypass as it seems to show on the new tempest fighter. Perfect for cooling the exhaust, especially if aerosols are added!
 

haavarla

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We would need an overlay with 117S engine to see any difference in size.
That would be very helpfull, thx.
 

FighterJock

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Fascinating. Is that izd 30? Looks like it has the same cold air bypass as it seems to show on the new tempest fighter. Perfect for cooling the exhaust, especially if aerosols are added!

I hope that it is izd 30, at least I hope that it is.
 

stealthflanker

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Well Salyut and Saturn have kind of their own thing in the development of AL-31F family.

and this makes me curious if they are still working with China.
 

Trident

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This is a development of the AL-31F from the Salyut company. I couldn't think of a better picture

Ok, copy that - the 2D background drawing is a Salyut AL-31FM variant. But what's the 3D overlaid CAD image, with the apparent 3rd stream ducts?

That long fan spinner reminds me of a certain unidentified Russian engine photo...
 

LukaszK

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Well, I read somewhere that izd 20 has already variable bypass (like YF-120).
But it was heavy - for large plane, and using old technology.
So I assume also izd 30 will have such. There are such information :
https://www.aviaport.ru/digest/2020/03/20/631483.html

"Важной особенностью конструкции, обеспечивающей получение новых возможностей, является изменение степени двухконтурности."
"An important design feature that provides new opportunities is the change in the degree of bypass."
 

stealthflanker

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Well, I read somewhere that izd 20 has already variable bypass (like YF-120).
But it was heavy - for large plane, and using old technology.
So I assume also izd 30 will have such. There are such information :
https://www.aviaport.ru/digest/2020/03/20/631483.html

"Важной особенностью конструкции, обеспечивающей получение новых возможностей, является изменение степени двухконтурности."
"An important design feature that provides new opportunities is the change in the degree of bypass."
It can also means simple bypass ratio change. e.g from 0.7 to 0.8. As larger engine means larger diameter and that allows for increasing bypass ratio.
 
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