PAK-FA / T-50: Russian 5th Generation Fighter

[Feanor]

From what we have garnered the engines currently in use seem to be a prototype of the engines to be used on the production variants. And the internal weapons bay, which will be located between the two engines, has not yet been installed.

 

[Scorpion82]

BTW the current issue of the German aviation magazine features an article about the PAK FA which states the engine designations AL-41F1 and AL-41F1S. It is stated that the AL-41F1 turbofans powering the prototype generate a reheat thrust of 147 kN.

It furthermore states that there will be 6 prototypes:
T-50KNS = not flyable prototype to be used for taxi and ground trials
T-50-0 = Static airframe for structural load testing
T-50-1/2/4 = Flying prototypes
T-50-3 = Static airframe for fatigue testing

It is said that T-50-2 is scheduled to conduct its first flight at the end of 2010.

 

[Aussie Digger]

Rumors PAK-FA uses prototype 117 (not 117S) engines for its first flight. Most likely these 117 engines will be installed on first serial PAK-FA as true 5-gen egines will not be ready by 2015.
Even 117 engines said to provide enough thrust for superuise, although not in optimal manner.

More thrust needed for supercruise without afterburner, this will actually reduce fuel consumtion.

Thrust isn't all that important for speed.

As an example, F100 engine equipped F-16's are barely able to make M2.0.

J79 engine equipped F-16's for Taiwan hit M2.05 at times and could have gone faster but the airframe wasn't cleared for it. Yet the F100 far exceeded the thrust output of the J79:

F100 - 22,000lbs of thrust (maximum in reheat).

J79 - 17,500lbs of thrust (maximum in reheat).

Why is this relevant? F100 makes much greater thrust than the J79 as shown, but the J79 is optimised for top end speed and maintains it's thrust better as the mach number rises because it had a much higher exhaust velocity.

High exhaust velocity is the best way to ensure a supercruise capability, but it usually infers other issues with the engine. The J79 for instance is a turbojet whereas the F100 is a turbofan.

The F100 is a far more economical and reliable engine for the majority of flight regimes than the J79. Acceleration and engine economy (both in fuel consumption and reliability and support cost) is also mostly far more useful for a fighter than outright performance.

Furthermore engines such as the F119 which ARE optimised for supercruising (ie: non-reheat) supersonic cruise performance generally provide pretty sucky subsonic performance and fuel consumption (SFC) and this has a great effect on aircraft designed for deep penetration strike missions.

So when some well-known but not well regarded commentators start boasting about PAK-FA being such a high performer AND boast such a long range, in an aircraft package no bigger than existing Flanker models, well one has to take these claims with a very large grain of salt.

Unless Russia has made engine technology leaps that dwarf what anyone else in the world has ever been able to achieve, then these claims are simply bogus.

Supercruising does not use the fuel that reheat function does on supersonic "dash" fighters I agree, but it DOES impose range penalties on an aircraft, which is why the F-22 being such a relatively large fighter has such a relatively poor combat range and why the F-35 WILL be superior in range to the F-22. Supercruising doesn't burn fuel like reheat, but it DOES burn far more than economical subsonic cruising...

It also explains why supercruising Concorde jets existed in the 70's but subsonic jetliners STILL dominate the market today and the Concorde is gone. The cost of a true supercruising capability in fuel and development is NOT trivial...

I find it equally implausible that any OTHER aircraft will achieve differently in the near future either...

 

[Toptob]

First of all, Aussie Digger thanks for your wonderfull post on engines. I learned something from that.

Second: Feanor said "And the internal weapons bay, which will be located between the two engines, has not yet been installed.] "

Now is that going to reduce the lift the body produces? As I understand it the space between the engines gives the aircraft more lift, am I correct if I understand that the weapons bay is going to fit in between the engines and that it will give less lift?

 

[Aussie Digger]

First of all, Aussie Digger thanks for your wonderfull post on engines. I learned something from that.

Second: Feanor said "And the internal weapons bay, which will be located between the two engines, has not yet been installed.] "

Now is that going to reduce the lift the body produces? As I understand it the space between the engines gives the aircraft more lift, am I correct if I understand that the weapons bay is going to fit in between the engines and that it will give less lift?

The broad underside of the PAK-FA will give it a large amount of body lift, just as the F-22 and F-35 share this design feature as well.

As an example:

F-35

http://www.jsf.mil/images/gallery/sdd/f35_test/b/sdd_f35testb_028.jpg

F-22

http://cdn-www.airliners.net/aviation-photos/photos/9/4/0/1065049.jpg

PAK-FA

http://www.ausairpower.net/Sukhoi-T-50-PAK-FA-First-Flight-8S.jpg

Common theme? All feature large relatively flat (less so in PAK-FA) fuselages that provide significant body lift. The weapons bay won't effect this significantly I shouldn't think.

 

[ghost]

From what we have garnered the engines currently in use seem to be a prototype of the engines to be used on the production variants. And the internal weapons bay, which will be located between the two engines, has not yet been installed.

I really like it. What else do you think hasn't been installed yet? The report in Russian media says that all the avionics and weapon controls would be added lately. Is it a common practice? Technically what we see then it's a flying fuselage with another type of engine, isn't?

 

[Haavarla]

Interesting wing design here.
High lift and high speed are two capabilities that comes to mind.

But are there any obvious trade-off from this wing design?

 

[plasmahawk]

Thrust isn't all that important for speed.

117 Engines

The Vesti Article and Video does say 117 Engines and also that these engines are redesigned to allow take off from 200M. The engine regulation/regulatory system is described by the specialist as a innovation, however, there is no further detail so its hard to guess what he is talking about. Also if you watch the video there are some shots of the R73E missle which is billed as the new hot weapon of this aircraft, although, the r73 has been around for quite some time.

the google translation is here: Google Translate

the original page with video is here: (let it buffer ) Âåñòè.Ru: Ò-50 âñòàåò íà êðûëî

Plas

 

[Feanor]

Fascinating article. It claims 5 radar antennaes in different positions around the airframe. The R-73 is allegedly the first missile being tested with the avionics for it.

 

[Aussie Digger]

Fascinating article. It claims 5 radar antennaes in different positions around the airframe. The R-73 is allegedly the first missile being tested with the avionics for it.

Radar warning receivers are going to have a field day...

:jump2

 

[Feanor]

Not if these are AESA arrays in LPI mode. Then again, the entire claim could be bogus or journalistic misinterpretation. However this wouldn't be out of line with earlier claims, about additional L-band AESA arrays in the front of the wings, and a possibly rear-ward radar.

 

[SpudmanWP]

The Russians have barely demonstrated AESA let alone LPI modes.

 

[Feanor]

The Russians have barely demonstrated AESA let alone LPI modes.

Allegedly two AESA radars are in testing right now. The Zhuk-AE for the MiG-35 and a new unnamed AESA array from Tikhomirov for the PAK-FA. What we get remains to be seen. I do share your skepticism.

 

[Scorpion82]

Allegedly two AESA radars are in testing right now. The Zhuk-AE for the MiG-35 and a new unnamed AESA array from Tikhomirov for the PAK-FA. What we get remains to be seen. I do share your skepticism.

The NIIP design for the PAK FA is designated Sh121 and also known as N050.

 

[Feanor]

Thanks for the correction. Anything else known about it? Other then that it's over 1500 modules, and currently undergoing ground testing.

 

[PhysicsMan]

Thanks for the correction. Anything else known about it? Other then that it's over 1500 modules, and currently undergoing ground testing.

Here's a schematic view of the supposed radar systems (floating around the net). #1 and #2 are x-band, and #3's are the L-band wing-mounted ones.

 

[owais.usmani]

Here's a schematic view of the supposed radar systems (floating around the net). #1 and #2 are x-band, and #3's are the L-band wing-mounted ones.

Here is another schematic of the proposed radar and weapons systems:

 

[nevidimka]

Some fan Art and Screen grabs.

 

[localhost127]

high-res shot from above...looks like she's been painted.

http://img442.imageshack.us/img442/9140/1266695508957397.jpg

 

[Feanor]

Where's that shot from? It looks a lot like an earlier shot from the first flight. Could it just be a shop?

Also there have been 3 flights to date, and two more prototypes are ready to fly.