The Indo Russian PAK-FA Project

negi · Post by **negi** » 23 Dec 2009 02:03

Kanson while I hate to speculate but given the nature of the topic and available info I would bet my money on the two engined design

1. The sheer size of the AESA radar displayed by the NIIP as posted here by Jai indicates the AC radome has to be pretty big.

2. Given the numerous reports on MTOW along with the internal weapons carriage and the dimensions of the PAK-FA (including the one in popular mechanics and translated by Igor) ; there is no mention of an engine in class of F135 on NPO saturn's website ; it is hence obvious we are looking towards a 117S or AL-41 powered twin engine configuration. A single engined PAK-FA powered by a 117s to me wont be able to SC with the kind of MTOW being peddled on the web.

I doubt if the RU aviation Industry has the means to run a parallel programme for a smaller single engined 5th generation fighter even with Indian monetary input.

Gaur · Post by **Gaur** » 23 Dec 2009 06:28

negi wrote: ...it is hence obvious we are looking towards a 117S or AL-41 powered twin engine configuration. ...

Only the initial prototypes are to be powered by Al-41. As opposed to much of the news relating to pak-fa, this is not speculation. The final engine for pak-fa is in development and is much more advanced with much greater thrust. However, at present, it is going though some problems which are hoped to be rectified soon.
This is mentioned in a Russian interview given by Saturn Director some time back. I will try to find the interview and post it here. But I guess, considering the amount of interest pak-fa generates, most here would have read it already.

sumshyam · Post by **sumshyam** » 23 Dec 2009 21:06

I don't understand it...one time they say....it is delayed...another time they talk of testing it....!

Russia to commence flight tests of FGFA

"In the end of December-beginning of January, we are not making any New Year presents, but flight tests will start shortly," Deputy Prime Minister Sergei Ivanov said.

another link

NRao · Post by **NRao** » 23 Dec 2009 21:46

sumshyam wrote:I don't understand it...one time they say....it is delayed...another time they talk of testing it....!

Russia to commence flight tests of FGFA

"In the end of December-beginning of January, we are not making any New Year presents, but flight tests will start shortly," Deputy Prime Minister Sergei Ivanov said.
another link

testing is dependent on factors that are fluid. Since the factors change, so does the date on which the testing can occur.

Let them take their time. What is the hurry?

sumshyam · Post by **sumshyam** » 23 Dec 2009 22:08

NRao wrote:What is the hurry?

AS a mechanical engineering student and as an enthusiast ...I wanna see the model....even if in pictures...!

Avi J · Post by **Avi J** » 24 Dec 2009 17:42

here is a transation of the original article in russian dated 24/12 /2009
confirmed by interfax

http://lenta.ru/news/2009/12/24/pakfa/

Russia a promising fifth-generation fighter - a promising frontline aviation aircraft complex (PAK FA) - the first jogging at the airfield of Komsomolsk-on-Amur Aircraft Production Association (KnAAPO). It is reported by Interfax, citing a source in the aviation industry. When it was held rollout of the aircraft and began his test was not specified.
After the rollout pilot started the engines and the plane started moving on the runway. During jogging PAK FA several times carried inhibition. Results produced two jogging. During the test was observed only employees KnAAPO. As expected the end of 2009 PAK FA will do some jogging, and in January 2010 made its first flight.
Officially, Russia's specifications prospective fighters were not reported. Presumably, PAK FA will be able to reach speeds of up to 2,1 thousand kilometers per hour. Range aircraft will be 5.5 thousand kilometers. Armament plane can be represented by 30-millimeter cannon. PAK FA will have 16 points of suspension, including eight located inside the fuselage.

Cain Marko · Post by **Cain Marko** » 24 Dec 2009 17:49

invi wrote:here is a transation of the original article in russian dated 24/12 /2009
confirmed by interfax

http://lenta.ru/news/2009/12/24/pakfa/

Russia a promising fifth-generation fighter - a promising frontline aviation aircraft complex (PAK FA) - the first jogging at the airfield of Komsomolsk-on-Amur Aircraft Production Association (KnAAPO). It is reported by Interfax, citing a source in the aviation industry. When it was held rollout of the aircraft and began his test was not specified.
After the rollout pilot started the engines and the plane started moving on the runway. During jogging PAK FA several times carried inhibition. Results produced two jogging. During the test was observed only employees KnAAPO. As expected the end of 2009 PAK FA will do some jogging, and in January 2010 made its first flight.
Officially, Russia's specifications prospective fighters were not reported. Presumably, PAK FA will be able to reach speeds of up to 2,1 thousand kilometers per hour. Range aircraft will be 5.5 thousand kilometers. Armament plane can be represented by 30-millimeter cannon. PAK FA will have 16 points of suspension, including eight located inside the fuselage.

Sweet. Jogging with inhibition - must have crazy knockers! Kudos!

CM

Avi J · Post by **Avi J** » 24 Dec 2009 18:01

ПАК ФА несколько раз осуществлял торможение.

thats the original phrase sir and the translated version sounded funny but the meaning was to imply that braking in between the taxi was carried out

Cain Marko · Post by **Cain Marko** » 24 Dec 2009 22:34

Yes, I understand, thx. Notch one up for google's translation - its almost always hilarious. BTW, welcome to BR. Nice to have another russian speaking member.

Also, any decent images based on the rollout? Can't wait really.

CM.

Avi J · Post by **Avi J** » 24 Dec 2009 23:59

x posting from EYE WITNESS sukhoi corp
sukhoi.ru
username of member GROOMI
translated from russian to english

i do not guarantee the exact nature of this and how far this is true just came across trying to share on BR

Writing. So true. They brought it to the taxiway, the preparation of 30 minutes, then brought the engines, the plane left the starting line (itself of course), the snake, turn on 360, again a small snake, stop, podgazoval, jogging and checking the brakes, turning on the 360 in the opposite direction, turning on the 180 and went back to the taxiway, after which he was taken away altogether. In general, everything was working and simply. Everything worked without a failure and it was at 5.

NRao · Post by **NRao** » 25 Dec 2009 01:56

Thanks invi.

Another few such taxi trials and I would think it should take to the air in a week or so.

SaiK · Post by **SaiK** » 25 Dec 2009 08:00

from royfc:-

PAK FA Makes First Taxi Run at KnAAPO Airfield

The Russian fifth generation future fighter, the future tactical aircraft aviation complex (PAK FA) , has made its first taxi runs at the KnAAPO ((Komsomol'sk-on-Amur Aviation Production Association)) airfield, Lenta.RU reports.

However, it is not being specified when in particular the airplane's roll out took place and when its tests began. After the roll-out, the airman started the engines and the airplane began moving along the runway. During the taxi run, the PAK FA was braked several times. Two taxi runs were made in all.

Only KnAAPO employees observed the test. As is expected, the PAK FA will make several more taxi runs before the end of 2009, and make first flight in January 2010.

Earlier Russia's vice premier, Sergey Ivanov, announced that the tests of the Russian fifth generation fighter will begin at the end of 2009 - start of 2010. The deputy defense minister, Vladimir Popovkin, announced in mid-September 2009, that the PAK FA, also known as the T-50 and "Article 701," will begin to reach the Russian air force inventory from 2015.

Source: 24.12.09, Avia.RU

http://www.docstoc.com/docs/document-pr ... d=12934262

Nihat · Post by **Nihat** » 25 Dec 2009 18:28

PAK FA will have 16 points of suspension, including eight located inside the fuselage.

16 hard points when stealth is not quite so important , that is quite something.

PAKFA could almost take on an entire squadron of older fighters and return to tell the story

Sagar G · Post by **Sagar G** » 25 Dec 2009 18:53

16 hard points when stealth is not quite so important , that is quite something.

PAK FA is a fifth generation stealth oriented plane or did I miss something

Nihat · Post by **Nihat** » 25 Dec 2009 19:09

8 hard points will be a part of the internal weapons bay and remaining 8 would be outside.

Sagar G · Post by **Sagar G** » 25 Dec 2009 19:57

I thought u missed the including part.

SaiK · Post by **SaiK** » 25 Dec 2009 20:26

in addition to the ^^inclusion^^ clause, pylons and weapon systems can be made stealthy too.

Sagar G · Post by **Sagar G** » 25 Dec 2009 20:33

pylons and weapon systems can be made stealthy too.

Are these operational in any AF's around the world or still under experimentation

SaiK · Post by **SaiK** » 25 Dec 2009 21:24

Sometime back on JASSM, there was a report on it being increased to 80% reliable from 60% failure rate. They(LM) are improving it quite a lot.

NRao · Post by **NRao** » 26 Dec 2009 22:06

No XMas sighting of Santa in PAK-FA? I was expecting a few more taxi runs, a nose-wheel-up perhaps, ......................... and a foto or two for new years.

I mean this is serious stuff, can party l8r on.

Gagan · Post by **Gagan** » 26 Dec 2009 22:58

No sightings of the Pak-FA, but I give you the Airbase and the Hanger where the beast lives.

This factory also builds a huge number of Su-27 derivatives, one can see several Su-30s with canards there (Possible MKIs)
This is also the city where the Nerpa nee INS Chakra was built at the neighbouring submarine factory. This Sub factory is where the Kilos go for refubishing.

Rahul M · Post by **Rahul M** » 26 Dec 2009 22:59

supposedly a model of PAK-FA, courtesy quadroFX @ oracle forums.

Gagan · Post by **Gagan** » 26 Dec 2009 23:11

We can see some Sukhoi 27 derivatives, including a canard Su-30 at left lower corner.
But can anyone identify the numerous other aircraft standing there? Are these UAV's of some kind? These are not the T-50.

NRao · Post by **NRao** » 27 Dec 2009 00:13

That model, I would think, is close to the ultimate.

However, I would like to see them exhausts take a different shape - somewhere down the line. I mean if it is going to take on the look of a YF, then might as well go the entire length. But that is a different story/thread.

For the funding they have had, it seems like a good product. RUian Scicom, though, IMVVHO, is far better and can actually produce a dynamite solution ............................ given the right environment.

negi · Post by **negi** » 27 Dec 2009 00:38

^ For 3D TVC the nozzles will have to be symmetrical about the center hence the circular cross section unlike the F-22 which has TVC only along the pitch axis.

KrishG · Post by **KrishG** » 27 Dec 2009 00:41

Rahul M wrote:supposedly a model of PAK-FA, courtesy quadroFX @ oracle forums.

That does resembles the Su-34 Fullback to an extent. But, willn't a Su-27-like intake ducts compromise the frontal RCS due to thermal visibility in the line of sight ??

Rahul M · Post by **Rahul M** » 27 Dec 2009 00:44

first, we don't know if this is the one. secondly, we can't see enough of the intakes (in fact we can't see them at all and can only guess their location or shape using our past experience with aircrafts) to pronounce them as su-27 like. it can well be that the engines themselves are in s-shaped ducts. simply put, hold yer horses !

negi · Post by **negi** » 27 Dec 2009 00:54

From what I can make from the pic (assuming this is closest to the final AC , as I remember seeing the pics of the same in KP forums, popular mechanics and even on Igor's Blog) ; the intakes are definitely not like the flanker family in this case the inlet manifold has a beveled opening with respect to both vertical and horizontal axis unlike the fulcrum/flanker whihc have intakes beveled only with respect to the vertical axis.

NRao · Post by **NRao** » 27 Dec 2009 01:07

^^^

I think I can see the intake and it does not seem to be the diamond shape the PAK-FA supposedly is supposed to have.

Negi,

Can that problem of vectoring not be solved with flat nozzles?

Gagan · Post by **Gagan** » 27 Dec 2009 03:29

The intakes seem to be somewhat like this:

One problem with 3D TVC is that it can't be hidden inside a protruding part like on the F-22. That'll obstruct some exhaust flow otherwise.
Secondly it has to be circular in shape.

The hot exhaust can be mixed with colder air to try and minimize the heat signature like on the F-22.

Cain Marko · Post by **Cain Marko** » 27 Dec 2009 08:29

NRao wrote:^^^

I think I can see the intake and it does not seem to be the diamond shape the PAK-FA supposedly is supposed to have.

The problem can be gotten over without diamond shape intakes too - the 1.44 didn't have them, nor does the S-37, nor the Tiffy, nor the Rafale.

Negi,

Can that problem of vectoring not be solved with flat nozzles?

FWIW,

The russkis always found the circular shape more useful. To quote Chepkin:

The AL-31FP boasts an axial exit nozzle. That is to say the nozzle is circular. It is known that your overseas counterparts used to try to solve the thrust vector control problem via the use of a flat nozzle that should be easier to swivel. What do you think of that?

In the late 1980s, we were engaged in the development of the flat nozzle too and conducted a thorough research. The Ufa-based Motor Scientific Production Enterprise under the guidance of Chief Designer Alexei A. Ryzhov manufactured an experimental flat nozzle that underwent a series of tests. The conclusions were as follows. Presently, the flat nozzle has two inherent snags which, in principle, have not been dealt with yet. Firstly, the turbine is round but the nozzle is flat with a distance between them being small. The distance cannot be increased because this would lead to an increase in the overall length of the aircraft, a loss of thrust, etc. While transforming the circular gas stream into the flat one, the nozzle, developed by Mr. Ryzhov, was losing 14-17% of thrust. Unfor-tunately, the gas stream cannot be "bent" as we would like it to. It has its own laws too. So far, no one has managed to transform the circular gas stream into the flat one without losing thrust. The very same snag was hit by the Americans in developing their F-117 featuring a non-afterburning engine. Such engines lose approximately 15% of thrust too. However, the F-117 is a specialised Stealth aircraft with the main requirement of ensuring "invisibility". It does not need a real good thrust/weight ratio. That is why the Americans put up deliberately with an unavoidable loss of thrust but benefited from reduced signatures.

Secondly, the other primary problem is weight. The circular TVC nozzle produces only tensile stress while the flat one exerts bending stress as well. Those stresses require special measures to be taken to ensure the nozzle strength in order to avoid deformation of the nozzle. Those measures mean additional weight. The flat nozzle made of metal is heavier than the circular one by approximately half a tonne. Mind you, the whole AL-31FP fitted with its circular swivel nozzle weighs a little bit more than 1500 kg only. So, the use of a flat nozzle implies an extra tonne at the rear of a plane (two-engine are meant here, which make up the most of modern fighters). The problem can be circumvented through the use of the "carbon-carbon" materials which have low specific weight and can stand high temperature. But they burn in the end anyway, since they are based on the very same coal. Nobody has solved the problem of preventing carbon-carbon units from burning during their operation as part of an aircraft engine. Currently, such materials covered by a thick layer of fire-resistant ceramics are used only in manufacturing the control surfaces of rocket engines. The latter are actually disposable since their operation never exceeds 40-50 seconds while an aircraft engine service life amounts to 1,000 hours or more.

From Vayu Sena.

CM

sumshyam · Post by **sumshyam** » 27 Dec 2009 08:48

Gagan wrote: The hot exhaust can be mixed with colder air to try and minimize the heat signature like on the F-22.

Gurus...Please explain....how this is can be done...I mean in terms of mechanism...!

Gaur · Post by **Gaur** » 27 Dec 2009 09:34

Cain Marko wrote:
NRao wrote:^^^

I think I can see the intake and it does not seem to be the diamond shape the PAK-FA supposedly is supposed to have.
The problem can be gotten over without diamond shape intakes too - the 1.44 didn't have them, nor does the S-37, nor the Tiffy, nor the Rafale.

The aircrafts you mention (S-37, Rafale etc), they have certain stealth features, but are not stealth aircrafts. So the problem in those aircrafts is not exactly "solved". However, although diamond shape inlets would most probably be featured in pak-fa, "diamond" in itself is not a magic shape that guarantees stealth.

Basically, there are two main methods to achieve stealth. One is faceting, which is used in F-117 (which basically scatters radar beams in all directions). More efficient method is to shape the airframe such that nearly every straight line in air frame is aligned in in direction of few selected spikes (which basically most of the reflected beams in a particular direction away from targeting radar). This is used in B-2, F-22, F-35. To successfully design an aircraft using this method, the inlets have to be aligned with the major surfaces of aircraft. So, "diamond" is not a magical shape that automatically ensures stealth. It is just that in these aircrafts (F-18, F-22, F-35), in order to align the inlet lips with major surfaces, the shape required is diamond. Note that this technique is also used in Rafale, but the inlet lips are not in diamond shape. In fact, if diamond shaped inlets would have been used in Rafale, it would have damaged its stealth characteristics.
This pic shows what I am talking about:

So, pak-fa may/may not require diamond shape inlets. Most probably it would. But if it uses some radical design change, then "diamond" is not some magic shape that would give it stealth.

Gagan · Post by **Gagan** » 27 Dec 2009 09:56

The US has tried to reduce the IR signature of its aircraft.

On the F-22 raptor there are small nozzels on the side protruding brackets which supposedly give out cooler air, which mixes with the exhaust of the engine. One can see such ducts on the rear of the Raptor in a close in picture.

The Commanche attack helicoptor had another innovative solution. The exhaust from the turbine engines was released all along the tail spine of the chopper so that the hot exhaust intermixed with the downwash from the main rotor and the IR signature was reduced.

Something like this: The Red is the hot exhaust. The blue is the cooler air.

Cain Marko · Post by **Cain Marko** » 27 Dec 2009 12:37

Gaur wrote: The aircrafts you mention (S-37, Rafale etc), they have certain stealth features, but are not stealth aircrafts. So the problem in those aircrafts is not exactly "solved".

Yes, I know; however, the above examples were to show that the diamond shape is not the only shape to maintain low rcs, but obviously fits well with the Raptor. The problem is not solved because of unstealthy inlet shapes but due to other more obvious reasons. The Shornet too has such inlets, does not make it a "stealth a/c". AFAIK, right angled faces are not to be offered, and this is what diamond shaped intakes do. The Tiffy has a smiley faced inlet shape.

As far as the Pakfa is concerned, we really don't know what is being offered - for all you know rafalesque inlets might be more suitable.

However, although diamond shape inlets would most probably be featured in pak-fa, "diamond" in itself is not a magic shape that guarantees stealth.

Precisely.

CM.

Austin · Post by **Austin** » 27 Dec 2009 13:50

The PAK-FA is the second most exciting project from Russian stable that I have been anticipating for years , I dont care if they have diamond wing or delta as each have their own pluses and minus as long as they get wide band RF stealth with that design , instead of RF band specific stealth.

I hope they do not compromise on basic superior flying qualities of the aircraft over some dream stealth , I am expecting some good T/W ratio ( ~ 1.5 )

Lets see what comes out in reality and if they indeed manage to hide the design with so many CGI floating around and to see if some one was really close with those CGI , Paraly reputation could be at stake as well here , he may turn out to be an overnight hero or might take a beating

Rahul M · Post by **Rahul M** » 27 Dec 2009 14:25

which is the first most exciting project ? borei ?

negi · Post by **negi** » 27 Dec 2009 14:27

Austin · Post by **Austin** » 27 Dec 2009 16:14

Rahul M wrote:which is the first most exciting project ? borei ?

Yeah their submarine program Borei and Yasen , its just more cool than PAK-FA or PAK-DA

sumshyam · Post by **sumshyam** » 27 Dec 2009 16:29

Austin wrote: PAK-DA

Can we not negotiate with them for participation in PAK-DA...I think we also need a stretegic bomber..Just asking out of query...!