The T-50 (PAK-FA) Thread

[Boberro]

Let alone PAK-FA.. it is not serial production bird. Maybe now it really looks like not full stealth plane or 4++ or -5 :D, but better wait for opinions when PAK will achieve final improvements. ;] It should be fully stealth plane then.

[GGTharos]

Unfortunately in reality the joke was on no one. There was no struggle.

 

^^^^^^

There's an old Cold War joke on Star program where NASA engineers struggled for several years to create a ballpoint pen capable of writing in zero gravity conditions...Soviet engineers simply relied on graphite pencils and sharpener...

[EtherealN]

Well mirmidon, I don't know anyone that would actually disparage the russian designers in the sense of trying to tell them they don't know their job.

 

Almost every person I know would, however, readily agree that they have suffered from the collapse of the USSR, since they had to labor for almost two decades with pretty much no funding at all. Given the hurdles the people at Sukhoi, MiG, Vympel etcetera had to overcome I think what they have done and are doing is absolutely amazing - but that doesn't change the fact that for those two decades the yankees were busy expanding their share of the world's military spending from ~40% to ~60%... The american and western designers, with that amount of funding, would have to be extremely incompetent to not build an edge.

 

That's why the PAK-FA is so interesting. It's pretty much foregone that it won't be a Raptor-killer, that's just not likely. But trying to figure out just how much they've caught up... THAT is the exciting thing. :)

[4c Hajduk Veljko]

Unfortunately in reality the joke was on no one. There was no struggle.

Yes that was a struggle. Otherwise they would just use a pencil.

 

Reminder: SAM = Stealth STOP!

[mikoyan]

^^^^^^

There's an old Cold War joke on Star program where NASA engineers struggled for several years to create a ballpoint pen capable of writing in zero gravity conditions...Soviet engineers simply relied on graphite pencils and sharpener...

 

practicality vs lest optimize by building something ultra- efficient and suited for the task even if it is super expensive.

[GGTharos]

You may want to check out the real story before making silly claims :)

 

Yes that was a struggle. Otherwise they would just use a pencil.

 

Reminder: SAM = Stealth STOP!

[Esac_mirmidon]

Totally agree, Ethereal.

[zakobi]

NEW! :thumbup:

 

 

Is that a new coating? or is it just the light?

[Antartis]

Guys, do not you told me, what the radar blocked? And how it works? In various forums I read it, but I do not understand the function.

[FeoFUN]

One of the our russian members - SV, has made a good guess, that T-50 has the variable air intake, that cover the fan in flight, when the panels are lower.

 

Here's the pics:

 

Part of original photo of T-50, you can clearly see the slits between variable panels.

 

The same slits, but highlighted.

 

This how it looks while the panels are lowered.

 

Same position of panels from the front. (but i'm pretty sure that variable panels, if they are, must be lower than that)

[Antartis]

Leaders not impressed by new Russian fighter

 

 

 

By Bruce Rolfsen - Staff writer

Posted : Monday Mar 22, 2010 9:50:52 EDT

The flying debut of Russia’s answer to the F-22 Raptor isn’t wowing Air Force leaders.

Dubbed the T-50 or PAK-FA, the fifth-generation stealth fighter jet made its maiden flight Jan. 29 — 47 minutes over eastern Russia — and has flown at least twice since then. The twin-engine jet will replace the MiG-29 Fulcrum and Su-27 Flanker, both fourth-generation front-line fighters.

The first operational T-50s should be delivered in 2015, the same year the Air Force expects its first F-35 Lightning II. Also a fifth-generation fighter, the F-35 has a single supersonic engine and stealth capabilities.

“I didn’t see anything … that would cause me to rethink plans for the F-22 or F-35,” Air Force Secretary Michael Donley told reporters Feb. 18 at the Air Force Association’s winter conference, held in Orlando, Fla.

“Russia has a robust [aircraft industry],” Donley added. “This is not a surprise in that context.”

The PAK-FA resembles the F-22 — distinctive tilted rear tail fins and all — and has many of the same high-tech features, including digital avionics, a phased-array radar and communications equipment to link the fighter to command and control centers, according to the Russian news agency Tass.

The Air Force ordered the last of its 187 F-22s in 2009. Russia has not had a new fighter in nearly 20 years; the Indian air force is also sponsoring development of a version of the T-50.

“It looks like a plane we’ve seen before,” Gen. Roger Brady, the air boss for NATO and commander of U.S. Air Forces in Europe, said at the conference.

Gen. Gary North, commander of Pacific Air Forces, made clear his impression of the fighter: “I guess the greatest flattery is how much they copy you.”

Still, the four-stars wonder whether the T-50 will live up to its fifth-generation billing.

“I don’t know if it’s really a fifth-generation aircraft,” Brady said. “What I do know is that it’s very clear that they’re working on a fifth-generation technology.”

For Brady, Russia’s push on the development front signals that the U.S. cannot settle for the status quo.

“The key is, we must continue to do fifth-generation and sixth-generation research and put money against it because other people clearly are,” Brady said.

North added that the Pentagon must ensure fourth-generation jets such as the F-15, F-16 and F/A-18 are continually upgraded.

“If we’re not going to buy more, what we’ve got to have is the very best that our sons and daughters go out to fight with,” he said.

In tandem with the T-50 project, Russia is developing a long-range bomber.

“We won’t limit ourselves to just one new model,” Prime Minister Vladimir Putin said March 1. “We must start work on a prospective long-range aircraft, our new strategic bomber.”

 

source http://www.airforcetimes.com/news/2010/03/airforce_russian_fighter_032210w/

[Antartis]

One of the our russian members - SV, has made a good guess, that T-50 has the variable air intake, that cover the fan in flight, when the panels are lower.

 

Feofun and SV, thanks...:thumbup:

[Pilotasso]

One of the our russian members - SV, has made a good guess, that T-50 has the variable air intake, that cover the fan in flight, when the panels are lower.

 

Here's the pics:

 

Part of original photo of T-50, you can clearly see the slits between variable panels.

 

The same slits, but highlighted.

 

This how it looks while the panels are lowered.

 

Same position of panels from the front. (but i'm pretty sure that variable panels, if they are, must be lower than that)

 

Looks like a shock wave ramp to me rather than a blocker, and as you can see it doenst block the engine completely.

[Vekkinho]

What makes you think it's not a simple FOD guard, same as used on Su-27 and MiG-29?!!

[Pilotasso]

Because it didnt seem to be using it in the taxi and runway and there arent any auxiliary breather slits on top of the lerxes, besides the 2 devices are easely distiguishable from each other.

Edited March 22, 2010 by Pilotasso

[mikoyan]

It looks like it has a similar system to the su-27 a lower grill and a second on the sides, the t-50 may have a ramp like the su-27 to prevent fod damage.

This is the first prototype, it doesn't even has radar, so it is just a test airframe to see the aircraft aerodynamics and performance. they may even change the cockpit. the su-27 prototype had the same cockpit design and they change it on the final version. Also lest not forget that the raptor like the su-27 got redesigned too.

there are some pictures of the engines and the banes in front of the compressor blades are black...I dare to say that they may be covered with ram paint. The russians are not totally new to stealth paint coat, there was an article form the 90s- 2000s that said that they had a su-25 painted with a special paint to reduce radar signature, the funny thing is that this airplane was placed on display at the Monino Museum by mistake but it was retired shortly after some find abut the mistake.

[Stickers]

Pentagon hating on the T-50.

 

http://militarytimes.com/news/2010/03/airforce_russian_fighter_032210w/

[zakobi]

Pentagon hating on the T-50.

 

http://militarytimes.com/news/2010/03/airforce_russian_fighter_032210w/

 

Seems someone is more or less butthurt, at the same time wanting more money :D

[sobek]

there are some pictures of the engines and the banes in front of the compressor blades are black...I dare to say that they may be covered with ram paint. The russians are not totally new to stealth paint coat, there was an article form the 90s- 2000s that said that they had a su-25 painted with a special paint to reduce radar signature, the funny thing is that this airplane was placed on display at the Monino Museum by mistake but it was retired shortly after some find abut the mistake.

 

I am no aircraft engineer, so don't take this for something it is not, but IMHO it is not possible to paint parts of the compressor to reduce it's radar signature or the west would already do that with all of it's planes. The compressor blades and guidevanes are under too much stress for a paint to be able to adhere for a sensible interval or why else do engineers elsewhere go to great lenghts to hide the blades? Again, just my opinion, but i believe that this is whishful thinking.

[GGTharos]

No, they're pointing out that they had already figured on foreign powers coming up with stealth aircraft.

 

Seems someone is more or less butthurt, at the same time wanting more money :D

[edward1976]

http://forums.eagle.ru/showpost.php?p=857056&postcount=2200

[Wilde]

http://forums.eagle.ru/showpost.php?p=857056&postcount=2200

Woah now that is one interesting solution. It's certainly much more subtle than I would have imagined it.

[Nate--IRL--]

I wonder what the performance penalty is for such a solution?

 

Nate

[Antartis]

Google translate

 

Prime Minister Vladimir Putin during his recent working visit to India for talks with President of India Pratibha Patil and Prime Minister Manmohan Singh, on the basis of which signed a package of joint documents on mutual cooperation.

 

During the visit, and discussions on joint development of fifth generation fighter. This topic experts call a landmark for further military-technical cooperation between the two countries.

 

India - Russia: Teamwork

 

The development of a strategic partnership with India, the Russian leadership considers a priority. Continue active cooperation in the aviation field, including in working together to fifth-generation fighter.

"As you know, we are in Russia so far conducted this work independently, have advanced significantly in this direction already, as experts say," raised on the wing "fifth-generation machine, - said Putin. - We are confident that our joint work will bring significant and noticeable effect. "

To address specific issues of cooperation in the government delegation attended the CEO of the state corporation "Russian Technologies" Chemezov, general director of Rosoboronexport, Anatoly Isaikin and General Director of Aviation Holding Company "Sukhoi" Mikhail Pogosyan.

In October 2007, in Moscow as part of the seventh meeting of the Russian-Indian intergovernmental commission on military cooperation signed an intergovernmental agreement to jointly develop and manufacture next-generation fighter.

Last year, the Indian Air Force prepared and handed over to the Russian party technical requirements for both single and double version of the fifth generation fighter.

29 January of this year from the airfield Dzemgi Airport Komsomolsk-on-Amur aviation production association. YA Gagarin

(KnAAPO) under the production codes "product T-50" made its first flight promising aviation complex tactical aircraft (PAK FA). To date, this aviation complex holds several flights.

The Indian side is very closely monitoring the situation on the implementation of the Russian PAK FA program.

According to experts, the implementation of Russian-Indian project to create the fifth generation aviation complex will become India's original entrance ticket to the club leaders in the global aviation industry. Today, nobody doubts that the Indian side has an appropriate base, experts produce advanced aircraft, new technologies and materials. The next step - the creation and implementation of design capacity in the development of new aircraft systems.

 

On the thorny path of creation

 

In early March, Prime Minister Vladimir Putin visited the JSC Sukhoi Design Bureau. He got acquainted with the work and products of this company, including the PAK FA, and held another meeting on the development of military-industrial complex and the support of the Armed Forces with modern armaments and military equipment.

Journalists were able to read some parts of Experimental Design Bureau, to communicate with professionals and learn some features of a T-50.

In Moscow alone, in the design of the T-50 involved serious design strength - 1.200 people plus in Komsomolsk-on-Amur - more than 400 in Novosibirsk - more than 200, in Taganrog - 100.

Hall of the detailed design Sukhoi resembled the office respectable company. It is equipped with modern computers. It made electronic models, designs, drawings of aircraft, its systems and avionics.

Hall connected lines with KnAAPO on which real-time information is passed on developments made in the bureau on an aggregate, site. Previously, it takes rolls of paper and spend considerable time on the delivery of their brand. In the agreement took months, now it takes several days and sometimes hours. In fact, information about changes can be directly released to the CNC machines used in the manufacture of parts.

Chief Designer of Sukhoi Design Bureau, Director of T-50, Alexander Davydenko outlined the major milestones of the project and answered questions.

In 2000, Russian Air Force formulated the concept of PAK FA. Competition task had three Russian aircraft firm.

Alternatives on the aerodynamics, equipping aircraft Sukhoi was about five. Of these combined criteria aerodynamic perfection, stability, manageability, deployment load chosen the most promising scheme. In 2002 the Government announced the results and in 2003, after receipt of this terms of reference Sukhoi started designing.

The company has successfully passed two major phases, which carried protection project. The draft of protected in 2004, technical - in 2006. Chairman of the Commission in the first and second case, the current Air Force Commander Col. Gen. Alexander Zelin said. In the committee's work included 50 people with involvement of more than 150 experts. "We were battered with all my heart, and there are no exceptions no one did, - said Davidenko. - To date, we have a military escort, rigidly check the quality of development and ongoing operations. The next step - testing. They have just begun.

During the development of conceptual, technical projects in the proposed version were made refinement, improvement, modernization, change, and eventually received aerial system, implemented at the moment.

- To what extent "the product of T-50" can be considered as a plane of 5-th generation?

- One hundred percent! The airplane is all mine. On it there is no contingency system. The navigation system has its own, native communication system, information and control system, indicators, too. Another thing is that he is not the whole, as they say, in the amount of aerodynamic tests and is not intended for testing weapons. Weapon system will be practiced on other machines.

- What is the use of composite materials, and what advantages does it give?

- The weight of the weight of the empty aircraft composites 25 percent. As the surface area - 70.

The advantage obtained primarily by mass. In the production after being necessary processes there is a significant decrease in the number of parts. Compared to the Su-27 on T-50 airframe to four times less detail. Reduced labor costs and production time results in a price reduction machine.

- How will the cooperation with India to look like?

- Design is anticipated on the basis of the previous work, which refuse to have no reason. Participation in the project will be fifty-fifty. On this basis, we will develop international cooperation. She has not only traced, but moved into the region of practical implementations. Indian partners want the T-50 could apply supersonic anti-missile BrahMos. We are working on it.

- What is the complexity, why postpone the creation PAK FA?

- We have a deadline for its acceptance into service in 2015. Complexities not, there is shortage of time. Mined principally new structure consisting of a huge number of composite materials. They must learn, develop new technologies, including the processing of large parts. Solve all the questions on their docking with the frame, ensuring integrity. All this requires time-consuming, which, as they say, can not be pressing.

- Compared with their American counterparts at the Russian PAK FA is what will be the price?

- Competitive. On the criterion of "efficiency - the cost of" our plane would be much better. Of course, it will be more expensive than our other machines, but this is due to the use of advanced systems, applications to the aviation complex of fundamentally new technologies. His predecessors are upgrading, but he's a machine of new generation.

- Calculate the dueling situation with the F-22 and F-35, anyone who knocks on what distances?

- Of course, simulated. Not sure, of course, we know exactly everything characteristics of American F-22 and F-35. We believe that the information received may not be entirely accurate, so try to have a number of options for additional supply capacity.

Features aircraft 5-th generation are all familiar. We tried to have us, they were better. For more information on this subject can not think out loud, do not have the right.

 

And instead of the heart - a flaming engine

 

A separate topic asked questions on aircraft engines for new aircraft systems firm. Initially they said Alexander Davidenko.

- Engine on the PAK FA is the same as the Su-35?

- The gas-dynamic characteristics of these engines are similar, but very important point. The engine on the Su-35 came just with our project, and not vice versa. It was developed for the T-50, so much so quickly and successfully, that it applied to the Su-35, but with the old control system for the entire family of AL-31.

The engine on the T-50 as compared with its predecessor fundamentally better. It has the elements of the fifth generation. A new "turbine, through which improved delivery characteristics. They can not quite optimal, but nevertheless all the given requirements, we implement a reserve. Significantly increased the engine thrust. He has a fundamentally different system of governance. It is digital, and when creating an engine of the second phase is likely to pass on him one by one. We are now at the expense of the system from the engine pulled out all the resources of his office.

Terms of Reference provided for the establishment of an aircraft with an engine first stage. So all this talk about the engine supposedly not that wrong. We do what we are given.

- Tell me how things are going to work on the engine of the second phase. In implementing its programs need to combine forces dvigatelestroiteley or give someone a preference?

- Terms of Reference for the engine of the second phase has not yet been issued. Conducted competitive activities avanproektu engine and the development of its individual units.

In my personal opinion, require co-operation, joint efforts. It should be borne in mind that we are "Saturn" is already very far advanced in terms of creating an engine 5-th generation.

At first glance it seems that business for small - probably a technical task. However, the "main problems are in a different plane," explained the chief designer of the Sukhoi Design Bureau, director of the Su-35 Igor Demin, answering the question, why not make the engine of the second phase.

According to him, you'll first need to decide on the state level with a few basic techniques. Without them the creation of a new engine generation is impossible. There must be systemic solutions to the levels of training, the establishment of the research base, rhythmic funding in full. It's no secret that before the plane was created in 8 years, and the engine for it - for 10. Experience shows that these terms do not undergo significant changes in current conditions.

To meet the tight time frame required to obtain resources and finances. This under-funding in one year, at what stage or later, will not eliminate the backlog on the project increased funding.

Creating a federal program can help with two conditions, said Igor Demin. The first - the strict implementation of all the parameters and strict control over the work of all involved in the project, up to the lowest level of business cooperation.

Second, no less important requirement. Project Manager required extensive powers. Once he creates a breakthrough product, or, as they say, an innovative, then he needs more rights and access to the head of state, bypassing the interim governing structure.

In addition, it is necessary to take into account past experience. For example, associated with the creation engine AL-31. Then, to achieve the desired result has allowed the union of scientific and technological capabilities in several ways. In addition to the EDB and industry, to develop and commercialize new engine part

VIAM, CIAM, NIAT. Each of the institutions had the necessary funding, scientific-technical base, trained manpower and plans, an attention to detail. Some people create content, others have developed processes for mass production. A huge contribution was made VVIA them. Professor NE Zhukovsky.

It is one of the chairs of the Academy are conducting research related to the special coated blades of the engine. She was targeting, were experts. Incidentally, other department as efficiently work on other symbolic themes and projects.

The greatest interest for EDO in this case are officers, and going past in VVIA them. NE Zhukovsky secondary education. This category includes engineers, previously studied at the Academy, then served in the regiments in leadership positions and to have additional training courses as prospective professionals. They have rich experience in the operation of aircraft, organizational skills. Earlier, some of them after completing the course were in the departments of the academy and doing research work in close collaboration with research institutes, EDB on various topics of practical importance for the country's defense. Reviews of these magnificent military researchers. After military service, they were invited to the scientific and design organizations.

Today, during the organizational and staff changes in the army is very important not to forget about this scientific potential. It is necessary to preserve the existing experience, to implement it in a modern guise of the Armed Forces of Russia and to create a new generation of technology.

[Antartis]

Airplane with intelligence

 

Deputy Executive Director for cockpit fighter Viktor Polyakov told that the main difference between the cabin T-50 is to maximize the care of electromechanical devices. There are two large liquid crystal display. They allow you to display for the pilot integrated information from different sources.

- In Russia and abroad, experts point out that the volume of information received as a pilot at some phases of flight, is redundant. Is there a problem at the T-50 and how it is solved?

- Yes, such a problem in the multi-air complexes created in Russia, the USA and other countries, there is. Implementation of fighter and attack functions requires different training, and their union in one plane - the highest professionalism pilot. In the United States until recently, walked towards the creation of twin engines.

To date feature AVIACOMPLEX 5-th generation - single. The pilot will perform all the tasks as intended by the provision of comprehensive information. This was made possible through the use of a different architecture avionics systems. In the previous generation of aircraft used by the so-called federal system aviation system now - integrated. Previously, each system had its own individual controls, indicators. Now the management of systems derived by RUS (handle control of the aircraft) and throttle (engine power control), and display - on two monitors.

If necessary, you can control the various systems using sensors on the monitor, which displays information on piloting, navigation, use of weapons and systems. All information is called a pilot, as necessary, rather than looms in front of him constantly and not divert attention. Work is underway to develop advanced system which allows to write on the glass protective headset pilot.

At the T-50 provide intellectual support for the crew. Borth computerized. The existing information system allows us to solve all the problems in the complex. It simultaneously processes all the information, controls systems, gives the pilot the necessary visual and audible indication. He can make changes to the program and receive messages in a more convenient for him consistency.

In the event of any failure information is displayed automatically on the priorities laid down in the program. The system not only provides information and analysis on the basis of damage, failure, removal of the airfield, the location of the enemy and many other factors tells the pilot how to act in any given situation.

There are differences in the ways of performing other tasks. Previously flying the pilot received from the control system warning of a possible hit in a corkscrew or other critical situations, and now they would prevent such a situation.

Su-30MKI electrically control system calculates the critical situation and, despite the actions of the pilot, as it smooths out his mistakes in the flying, do not allow the regime in which the aircraft can, for example, fall into a tailspin. In addition, the "thirty" There are still the automatic control system, control signals, air signals. At the T-50 combines them into a comprehensive management system. Integration allows for a smaller number of systems easier and better perform the same function.

- The pilot has the ability to disable some of these functions on piloting, if he deems it for one reason or another it unnecessary in the performance of a combat mission?

- This is possible when performing tests to verify certain supercritical conditions, opportunities for the aircraft on its further development. In my opinion, for the combat pilot of such permit will not. The ability to execute well piloting the maximum, and the yield for them is fraught with the loss of the aircraft. If the combatant units will be some suggestions, we commissioned Air Force to consider, will conduct the test, go to completion.

 

Youth Factor

 

The first flights of the T-50 aircraft among fans caused excitement. Some of their representatives say that first of all be technically re-equip the Sukhoi, attract the young professionals, and for this to begin their training in various specialized institutions. Wishers with his advice late at least ten years.

Technical re-equipment is in full swing, and young professionals already involved in the creation of aviation complex of 5-th generation. You can verify this by visiting the Sukhoi Design Bureau.

In the design office of youth working on areas of design, calculations. Its activity is the company's management evaluates how effective.

Jobs for young specialists in the field of designing with computers. Each of them costs about 1,8 million rubles. Do calculators - 3 million rubles, he more powerful computers and more expensive software. Youth are more adapted to work on such systems.

As explained by the chief designer of the Sukhoi Design Bureau, director of the Su-35 Igor Demin, unfortunately, there are pluses than minuses. Create structures must feel his hands. Young professionals, knowing computer technology, fewer own tactile sensations. Before performing the job the chief designer, the youth worked with real materials and a large part of the experience received by the personal experience of learning how to work this or that element of the aircraft on the stand. No less important was communication with those who makes parts for aircraft. They are sometimes assumed "tips", after which the machine has undergone various changes. Young people today do not receive such an experience.

The way out of this impasse in the Sukhoi Design Bureau has already been tested. At first, the young professional experienced staff, and explains what, why, why, and how it works. Then a young specialist direct on KnAAPO for learning about how to design a site or other development is implemented in a metal composite. "Let him look, understand that not everything you see on a computer as easy to put into production", - said I. Demin. Such trips add experience and give a good impetus to the creative work. Yet the current specialists in a better situation with respect to the older generation. They have a more effective framework to implement their ideas.

As an example, the work crews digital complex calculation programs. It deals with a huge number of calculations before the start of design and during it. Checks on aircraft aerodynamic properties, aeroelasticity, strength, vibration, and many other parameters.

Of course, all its decisions leading designer, figuratively speaking, feels her fingertips. Helps long-term experience gained in the process of participation in various design programs. However, it is often necessary to test new ideas in mathematical values, and then no payments are not enough.

Used for this experimental model is built airplane or its parts and conducted a study of the proposed design changes. In modern times the volume of such work is done by computer simulation. It helps reduce design time and at times, and sometimes by an order to reduce the financial costs when searching for the optimal improvement of the aircraft or any of its elements. That is as soon as it was found, tested, proven method of calculation and informed design decisions on the placement of gas rod on the T-50.

It is equally important and responsible work in the department of management at the stand seminatural simulation for autonomous mining CRS-50 in conjunction with real drive product T-50.

Features of this digital system having a quadruple redundancy, in that the process of developing a class of lost mobile mechanical wiring. Control points are located in the cabin, and there are also calculators and drives a specific control surfaces.

The main purpose of the stand - check work together control units with hydraulic drives, as well as verification of algorithms for systems management and operations of the entire system. New technologies have given an order of magnitude greater opportunities for the study of systems.

The stand allows the testing of algorithms, operating systems, provides an opportunity to observe its parameters, simulate failures, outages as a result of combat damage to different blocks. It then examines the work of the system, and young professionals convinced that the denial does not lead to a catastrophic situation. If such a threat is detected, it is subject to elimination, refinement software, and further verification.

"We are sure that all units, units interact with each other as required, and implement those laws, which are incorporated in the logic of the software, - stressed the head of the management system and added: - Without a thorough check on the stand of the fifth generation aircraft had no right to to fly.

In conclusion, reported that the Director General of Sukhoi "Mikhail Pogosyan said the possible signing in the near future supplementary agreement, the qualifying format for India's involvement in the project for Indo-Russian fifth-generation aircraft.

source http://www.redstar.ru/2010/03/24_03/2_03.html