The T-50 (PAK-FA) Thread

[aaron886]

It would probably increase radar cross-section (RCS) too.

 

You know, I was thinking just the opposite. I can't imagine that open area being a positive for RCS when evaluated from any angle but frontal. Am I barking up the wrong tree here?

[Namenlos Ein]

http://bastion-karpenko.narod.ru/photo_T-50_MAKS-2011.html

 

Zhukovsky, December 2012.

Edited December 18, 2012 by Namenlos Ein

[4c Hajduk Veljko]

Planes are made out of trade-offs. What's that 3D TVC trading off? Is it worth it?

Why bother with 2D TVC at all? Just use same ol` none TVC engines? It is less expansive and more reliable. Right?

 

Reminder: SAM = Stealth STOP!

[EtherealN]

It's less expensive, yeah.

 

But seriously, this is not a complicated question. I'll illustrate it for you:

 

No TVC: Simple.

2D TVC: somewhat complex, good performance gains.

3D TVC: extremely complex, slightly better perfomance gains.

 

Now, do you then throw tonnes of extra money for the small gains between 2D and 3D? Especially considering that said complexity might translate not only to greater production cost but also to greater maintenance cost and, extremely critically, to potentially severely reduced availability rates? (Meaning that to maintain a given mission readiness, you'll need a lot more aircraft?)

[Alfa]

Like Combatace said, the image you found is actually very old - I knew I had seen it before somewhere, but couldn't remember what exactly it was about.

 

On further investigation it turns out that it was an early 90'ies test concerning engine IR signature reduction meassures(3 additional images attached). Whether it also involved some experimenting with 2D TVC I don't know, but its definately not a current development concerning the PAK-FA :) .

 

The PAK-FA is scheduled to get new engines, but there is no indication that these will have a nozzle design like that of the F-22 - so far the only published info concerns weight reduction(as compared with the current engines) and expected power ratings of some 176 kn in AB per engine.

 

 

 

 

I don't think so - it seems a completely different approach to that used on the Su-37 (or currently on the PAK-FA) and much more of an investigation into the approach used on the F-22

Does this:

 

 

look like a precursor of this:

 

 

or an investigation of this approach ?

[marcos]

Are the PAK-FA's internal pylons spring loaded, because they appear to pop out when the bays open in the picture?

 

[4c Hajduk Veljko]

3D TVC: extremely complex ...

How do you know the level of complexity? Do you have detailed description of how it is implemented (prints, schematics, MTBF's date ...)? Let us not undermine Russian sense of simplicity when it comes to military equipment. Russians make simple things that work.

[ФрогФут]

Planes are made out of trade-offs. What's that 3D TVC trading off? Is it worth it?

Additional rudder channel stability and control on high AoA, for example.

[Pilotasso]

The Eurofighter has s 3D nozzle as option, no clients wanted it so far.

[EtherealN]

How do you know the level of complexity? Do you have detailed description of how it is implemented (prints, schematics, MTBF's date ...)? Let us not undermine Russian sense of simplicity when it comes to military equipment. Russians make simple things that work.

 

Okey, so everyone that does that stuff for a living are idiots that don't have your information? ;)

 

Seriously, the fact is that evidently people aren't using it to the extent that would otherwise seem prudent. It probably makes sense that they have some reason for this, no? So what we have done here is propose possible explanations for this conundrum.

 

But if you want to replace observed fact with fantasy, that's fine. :) What we know is that it's possible, but for some reason most don't want it. This does not preclude the fact that someone will, at some point, make a different judgement. You know, the same way some people want an automatic instead of shifter in spite of the automatic eating more gas and costing more in failures and maintenance with very very limited added utility.

[Griffin]

Are the PAK-FA's internal pylons spring loaded, because they appear to pop out when the bays open in the picture?

To me that looks photoshopped.

[combatace]

Are the PAK-FA's internal pylons spring loaded, because they appear to pop out when the bays open in the picture?

 

 

Its not the pic of real one. Its a 3d model.

[marcos]

To me that looks photoshopped.

2 photoshops on same plane?

 

 

 

 

 

 

 

Edited December 18, 2012 by marcos

[4c Hajduk Veljko]

Okey, so everyone that does that stuff for a living are idiots that don't have your information? ;)

I've never said anything like that. And it wasn't me who brought the issue of the TVC complexity in this discussion. I asked what was the base of the arguing the complexity of 3D nozzles?

 

It is more then obvious that 3D is more complex then 2D. But I don't know how reliable is 3D or how unreliable is 2D. So do we have any data that we can use for any real discussion? If not, we can only guess and speculate ...

 

We do know that Sukhoi implemented 2D TVC long time ago. Sukhoi 30MKI was the only airplane in the world, in service, with TVC engines until F-22 came along. India had more advanced engines (in service) then USA at the time ...

[Vekkinho]

The "2d tvc" shown here was primarily intended for IR signature reduction.

 

Like Combatace said, the image you found is actually very old - I knew I had seen it before somewhere, but couldn't remember what exactly it was about.

 

On further investigation it turns out that it was an early 90'ies test concerning engine IR signature reduction meassures(3 additional images attached). Whether it also involved some experimenting with 2D TVC I don't know, but its definately not a current development concerning the PAK-FA .

 

The aircraft in picture was a Lyulka AL-31F-M1 testbed, it's only purpose was 2D TVC testing. No significant IR sig reduction was recorded nor targeted.

 

Development and logic of 2D TVC started about the same time in both western and eastern parts of the world, hence the analogues and similarities.

 

F-22 engine development had more resources (read dollars) as usual so it's engines were prefected to a serial production standard while AL-31F-M1 system turned out "too bulky", complex and expensive and was ruled out in favor of later 2D "de Laval" nozzle of Lyulka AL-31P as seen on T-10M-11 or if you wish Su-37 "Terminator".

Edited December 18, 2012 by Vekkinho

[Vekkinho]

Guys, back in late '70s we had 14 prototypes of T-10 (Su-27) before T-10-15 which was the first aircraft with AL-31 engine that became serial engine of later Su-27. So have a little faith with PAK-FA...we just reached No4.

 

However, what do you expect to see on a PAK-FA? Stealthy jet pipes? Why? Business end of PAK-FA looks stealthy enough so far and that's what really matters.

[Pilotasso]

Someone said, cannot remember who or particular details, that the business end of the new SU-XX will depict a nozzle of rectangular section (like F-22), but tilted in an angle for V shape dual plane 2D TVC. That would look radical.

[Vekkinho]

Let's wait and see, I can hardly believe that KnAAPO knows the final result!

[Vekkinho]

Its not the pic of real one. Its a 3d model.

 

Yeah, very likely!

 

However, here's the

(@1:50)

[Alfa]

The aircraft in picture was a Lyulka AL-31F-M1 testbed, it's only purpose was 2D TVC testing. No significant IR sig reduction was recorded nor targeted.

 

Development and logic of 2D TVC started about the same time in both western and eastern parts of the world, hence the analogues and similarities.

 

F-22 engine development had more resources (read dollars) as usual so it's engines were prefected to a serial production standard while AL-31F-M1 system turned out "too bulky", complex and expensive and was ruled out in favor of later 2D "de Laval" nozzle of Lyulka AL-31P as seen on T-10M-11 or if you wish Su-37 "Terminator".

 

Interesting - do you have a source for this Vekkinho?(would like to read more about it).

 

I also thought it was an early 2D TVC experiment(looks more like that than thermal supression meassures) and at the corner of my mind I remember having read once that such a design was initially investigated, but abandonned in favour of the moving nozzle system.

 

However, a quick interweb search came up with the claim that it was all about IR signature reduction :hmm: .

 

Anyway, I think you got the engine designation wrong though - AL-31F-M1 is AFAIK simply an uprated(max thrust in AB raised from 12500 to 13500 kgf) version of the standard AL-31F: http://www.salut.ru/ViewTopic.php?Id=662

Edited December 18, 2012 by Alfa

[4c Hajduk Veljko]

Anyway, I think you got the engine designation wrong though - AL-31F-M1 is AFAIK simply an uprated(max thrust in AB raised from 12500 to 13500 kgf) version of the standard AL-31F: http://www.salut.ru/ViewTopic.php?Id=662

Well, it was AL-31F-M1 with 2D vectoring nozzle for testing purpose only.

[Alfa]

Guys, back in late '70s we had 14 prototypes of T-10 (Su-27) before T-10-15 which was the first aircraft with AL-31 engine that became serial engine of later Su-27. So have a little faith with PAK-FA...we just reached No4.

 

Yes but the T-10 as such was completely redesigned because it turned out that initial performance characteristics were inadequate - i.e. practically an entirely new airframe and not just a question of engines.

 

I doubt we will see something similar with the T-50 though - minor refinements and new engines yes, but I wouldn't expect radical design changes.

[Alfa]

Well, it was AL-31F-M1 with 2D vectoring nozzle for testing purpose only.

 

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.

[combatace]

Yeah, very likely!

 

However, here's the

(@1:50)

 

Wow! They started weapon systems testing too. Great!

[F-23A]

The aircraft in picture was a Lyulka AL-31F-M1 testbed, it's only purpose was 2D TVC testing. No significant IR sig reduction was recorded nor targeted.

 

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

 

Yeah, very likely!

 

However, here's the

(@1:50)

 

That's CGI.