The T-50 (PAK-FA) Thread

[4c Hajduk Veljko]

I kind of doubt that Hajduk - if you look at the link I posted, you can read that the AL-31F-M1 engine is quite recent and approved for production only by 2007, while AFAIK that 2D nozzle experiment is far older.

You might be right. According to Yefim Gordon, Su-27 book,, The Su-27UB-LL-UV (PS), (PS stands for flat nozzle, 2D TVC) was converted to a TVC test bed in 1990. Although Yefim does not specify which engine was used for this test. Nevertheless, apparently, this nozzle, indeed, produced reduced IR heat signature, but had other problems. Eventually research on "flat", 2D exhaust was abandoned in favor of "rounded" 3D TVC.

[4c Hajduk Veljko]

There is an interview with Pogosyan where he clearly states that it was for IR signature reduction and that a significant reduction was observed.

Yefim Gordon's book, page 101, also talks about IR heat signature reduction with this type of test 2D TVC engine.

[Alfa]

You might be right. According to Yefim Gordon, Su-27 book,, The Su-27UB-LL-UV (PS), (PS stands for flat nozzle, 2D TVC) was converted to a TVC test bed in 1990. Although Yefim does not specify which engine was used for this test. Nevertheless, apparently, this nozzle, indeed, produced reduced IR heat signature, but had other problems. Eventually research on "flat", 2D exhaust was abandoned in favor of "rounded" 3D TVC.

 

Yes thats what I had in the far corners of memory - didn't recall the designation of the test bed though.

 

Thanks for digging out the info Hajduk.

[marcos]

Yeah, very likely!

 

However, here's the

(@1:50)

Wow that thing plopped out very fast.

[Flаnker]

[Sov13t]

Yeah, very likely!

 

However, here's the

(@1:50)

 

Not a real launch, nor a real aircraft. Animation.

 

Edit: Here is the original:

Edited December 19, 2012 by Sov13t

[marcos]

Not a real launch, nor a real aircraft. Animation.

 

Edit: Here is the original:

Special effects.

[Pilotasso]

 

Whats that window under the pit?

[EtherealN]

MWS receiver maybe? If I'm thinking about the same thing you are.

[sobek]

Seems a bit odd positioned fo a MWS sensor.

[EtherealN]

Could be a webcam. :D

[Pilotasso]

Theres also a lump under the nose, if we find another at the rear we could very well suspect IR MWS.

[Griffin]

Whats that window under the pit?

 

http://www.defence.pk/forums/indian-defence/118201-sukhoi-pak-fa-fgfa-updates-news-discussions-71.html#post3696649

 

http://vitalykuzmin.net/?q=node/387

 

 

 

Edited December 19, 2012 by Griffin

[Griffin]

Claimed to be the L-band radar in the leading edges.

 

[Vekkinho]

You might be right. According to Yefim Gordon, Su-27 book,, The Su-27UB-LL-UV (PS), (PS stands for flat nozzle, 2D TVC) was converted to a TVC test bed in 1990. Although Yefim does not specify which engine was used for this test. Nevertheless, apparently, this nozzle, indeed, produced reduced IR heat signature, but had other problems. Eventually research on "flat", 2D exhaust was abandoned in favor of "rounded" 3D TVC.

 

Don't know if Yefim knows that there was LL-UV KS (круглое сопло=rounded nozzle) development taking place at Saturn Buerau but at the same time but LL-UV PS (плоско сопло=flat exhaust) was tested by OKB Sukhoi?

 

Saturn's 2D TVC KS was first finished and fitted to (IIRC) Test pilot's #595 aircraft and it was first airborne. It kinda remided me of F-15 ACTIVE.

 

Sukhoi's PS flat nozzle development was supervised by Pogosyan himself. It was a F-15MTD look alike. I don't remember any reports of reduced heat signature with this boxy installation but it could probably act as a thrust reverser for STOL. Anyway it was too bulky and complex. It also deformed aircraft's weight center point and finally abandoned in favor of Saturn's KS.

[sobek]

Claimed to be the L-band radar in the leading edges.

 

Would that be a phased array?

[Vekkinho]

Whats that window under the pit?

 

It's a "rear view mirror", looks no better than ordinary camera feeding MFDs with real time picture of 3 and 9o'clock view.

Edited December 19, 2012 by Vekkinho

[Vekkinho]

Theres also a lump under the nose, if we find another at the rear we could very well suspect IR MWS.

 

Could also be some kind of optical or IR sensor or ground mapping device...

[4c Hajduk Veljko]

Would that be a phased array?

I don't know what band phased array radars work at, but L band means a specific frequency range. Stealth aircraft can be detected (and tracked?) with L band radar. I am not sure if L band is good enough for AA missile guidance/engagement.

[sobek]

I don't know what band phased array radars work at

 

You can do phased arrays with almost any wavelength, the tradoff being that angular resolution depends on the ratio between aperture size and wavelength or wave number, for that matter, ergo greater wavelength, greater aperture size for same resolution. The reason why i asked is that if that is indeed a phase-angle relationship based receiver array, it can only give azimuth and no elevation data (at least as far as i am up to date on phased array mechanics). If that is not only a receiver but a transmitter as well, i would very much like to know how elevation beam steering is supposed to work with that thing.

Edited December 19, 2012 by sobek

[Weta43]

Given the number of optical trackers covering the surface of the T-50, couldn't they be tracking the spatial position of a number of linked planes and using the combined individual planes' arrays to get a large distributed 3d array (as for the square kilometre array RT)? that wold increase the angular resolution, and might also (as the elements of the array can be displaced in the vertical and horizontal) give elevation information ?

[Vekkinho]

^^^^

That sounds too complicated...

[4c Hajduk Veljko]

^^^^

That sounds too complicated...

I agree. :smilewink:

[Pilotasso]

L band might be used to bypass stealth measures like soft contouring, but on the other hand it doesnt circuvent property of faceting i.e. reflecting the waves away from the source, not to mention in order to provide guidance for weapons they would have to have much bigger radomes to pick up such long wavelengths.

[Weta43]

That sounds too complicated...

For you ? or for a computer ?

It's not cutting edge technology to make such an array on the ground, the only tricky bit would be to know the position of each aircraft accurately while in the air, and then collect and process the data - but the Russians have a history of doing things that were too hard - who got the first PESA radar into the air ?

 

See also - "The APG-71.. is capable of a 460 mile (740 km) range, but the (F-14) antenna design limits this to only 230 miles (370 km). Use of datalinked data allows two or more F-14D's to operate the system at its maximum range."

 

not to mention in order to provide guidance for weapons they would have to have much bigger radomes to pick up such long wavelengths.

Not if they data link to get a dispersed array as a single virtual radome.