PAK FA, T-50: News #1

Thanks GarryB

They might get the first batch of T-50s in 2015, but I rather suspect operational units wont get them till 2017-2018 because the flight and operations manuals need to be drawn up. Tactics worked out and perfected, etc etc.

Mindstorm wrote:

1) A continually operating pan-frequency field around the whole aircraft except its radar dome ("around" which the plasma "screen" would be generated).
2) A purposely designed frequency-selective screen in front of the radar dish and perfectly collimated ,both in exit and access, with the pseudo-random frequency hopping sequence of the active radar.

Some information on the principles of operation of this second device was presented by Prof. A.Lagarkov in an article i already posted in another thread .

http://vivovoco.rsl.ru/VV/JOURNAL/VRAN/03_10/STELLS.HTM

While the above explanation can be brought into practice it is also essential to state that there is a 3 LEVEL stealth entropy concept that states that the convolution of the nature of the environment and the properties of the blue force object define the amount of distance that can be traveled without being understood as a true threat by the red force.Analytically the environment can be dense and abstract like a jungle or a forest area, can be built like a city or can be open like the sky. Moreover the properties of the blue object are its outer form and geometry and its original colourings.The 3 LEVELS are




This classification helps to examine the blue force object relevant adaptations. The classication of the environment is based on the criteria of radar clutter and optical viewing ability. Both are factors that affect the viewing performance of the respective electromagnetic and optical sensor.

Fifth-generation fighter will soon begin test for Super Maneuverability

MOSCOW, August 16 - RIA Novosti. Fifth-generation fighter PAK FA (T-50) will soon begin testing maneuverability, said on Thursday honored test pilot and Hero of Russia, Sergei Bogdan.

Currently involved in testing three prototypes fifth-generation fighter. This year, to connect the fourth plane.

"The plane of the fifth generation in the near future, the program proceeds to test for super maneuverability. And those figures who now plays Su-35, T-50 aircraft in the near future will also be ready to perform," - said in an interview Bogdan "Russia 24".

He noted that unlike the Su-35 (which is a plane 4 + + generation), the fifth generation fighter aircraft greater wing area, larger volume of fuel, the engine with higher thrust.

According to Bogdan, agility T-50 is just more, despite the great demands of his "signature." "There are all conditions that the aircraft will be significantly better than the Su-35", - said Bohdan.

Comparing the T-50 aircraft with an American fifth-generation fighter F-22 "Raptor", he said that our T-50 came later, so all the shortcomings that were identified from the Americans, were taken into account when creating a Russian aircraft.

"Our Su-30MKI in 1997 on the handling characteristics showed no worse than the" Raptor ". Have passed since 15 years. By the fact that" Raptor "shows now, we can judge that by handling it does not beat that plane , "- said Bogdan.

He stressed that the tactical maneuvers with the aircraft Malaysia and India show that Russian planes prevail in a "skirmish."

"I think our strike aircraft developed in the right direction", - said Bohdan.

Sujoy wrote:

Mindstorm wrote:

1) A continually operating pan-frequency field around the whole aircraft except its radar dome ("around" which the plasma "screen" would be generated).
2) A purposely designed frequency-selective screen in front of the radar dish and perfectly collimated ,both in exit and access, with the pseudo-random frequency hopping sequence of the active radar.

Some information on the principles of operation of this second device was presented by Prof. A.Lagarkov in an article i already posted in another thread .

http://vivovoco.rsl.ru/VV/JOURNAL/VRAN/03_10/STELLS.HTM

While the above explanation can be brought into practice it is also essential to state that there is a 3 LEVEL stealth entropy concept that states that the convolution of the nature of the environment and the properties of the blue force object define the amount of distance that can be traveled without being understood as a true threat by the red force.Analytically the environment can be dense and abstract like a jungle or a forest area, can be built like a city or can be open like the sky. Moreover the properties of the blue object are its outer form and geometry and its original colourings.The 3 LEVELS are




This classification helps to examine the blue force object relevant adaptations. The classication of the environment is based on the criteria of radar clutter and optical viewing ability. Both are factors that affect the viewing performance of the respective electromagnetic and optical sensor.

Sujoy ,no offence , but what would be that ?

From what i can understand of this....very very rough prospect...it represent,at best, a kind of very simple exposition of the elementary principles at the basis of background-figure factors of distiction or blurring ; it could interest...at best.... someone wanting to choose ,at a very amateurish level, the patterns of veicles or uniform's camouflage for a particular environment .
Now, always with the due respect :


What ,for the sake of all star of universe, is its point with the subject was in discussion ?


If it exist is well beyond mine level of understanding.

I think you are confusing factors for ground based vehicles and material for aircraft.

Since the early 1970s look down radar has dealt with low flying aircraft moving against ground clutter, from forests and cities to deserts and over the sea. Very simply the solution is to analyse the radar returns.


When you listen to a sound wave is a good example... the siren on a vehicle that is approaching sounds higher pitched than it does if it is sitting next to you stationary. That is because the motion of the source of the sound is compressing the wave so it increases the pitch of the sound as it approaches. There is a similar effect when it has passed and is moving away... the pitch is reduced as the waves are stretched.

When radar waves hit a target if the radar is stationary and the target is stationary then the radar returns look very much like the radar signals that were emitted. If the radar or the target are moving then there is a shift in frequency in the signal called the Dopplar effect or Dopplar Shift. The point is that from an aircraft looking down the entire earth is a reflector but the ground and the stationary things on the ground can be identified because their dopplar shift is the same. The display on the radar console displays what it is set to display... it can display everything, in which case the whole screen would be lit up with the ground. When looking up however it would show all moving (aircraft) and stationary (airships, helos etc etc) things in the field of view of the radar.

Seeing everything when looking down is useless so they filter the information and ignore the stuff that is not interesting that is called noise. Unless you want cars on motorways to appear on your radar screen you set a speed of 150km/h or so and get the radar to filter out everything that is going slower than that speed. This leaves all the low flying aircraft, including stealth aircraft if the radar can detect and track targets that small.

If it is powerful enough to do that then identifying the insect sized targets flying at 600km/h as being stealth targets should be fairly straight forward.

The key is that these stealth targets will be moving so there is no problems tracking them over flat open spaces or dense jungles.

Mindstorm wrote:
Sujoy ,no offence , but what would be that ?

From what i can understand of this....very very rough prospect...it represent,at best, a kind of very simple exposition of the elementary principles at the basis of background-figure factors of distiction or blurring ; it could interest...at best.... someone wanting to choose ,at a very amateurish level, the patterns of veicles or uniform's camouflage for a particular environment .
Now, always with the due respect :

What ,for the sake of all star of universe, is its point with the subject was in discussion ?

If it exist is well beyond mine level of understanding.

Mindstorm & GarryB ,

Apologies if I have not been able to explain things properly . I am just sharing here some of the research that can be done ( similar research is being done in parts of Europe & Asia,so this is not my brainchild per se ) to design a stealth aircraft. I have always argued that STEALTH as advertised by the US is simply not stealth as US stealth aircrafts are optimized for just 1 max 2 radar bands.

The premise here is why can't we make a truly all-aspect invisible to radar stealth fighter. Since only a very small signal is back scattered form an airborne target.If we see the stealth aircraft from a different perspective it will lead to technological innovations which lead to an edge in operations.


Definition 1. Hidden Object of a Stealth Aircraft.

The elements of an aircraft that the blue force stealth aircraft designer wishes to hide from the respective red force sensors.

hidden stealth

f=electromagnetic + electro optical+active emmissions + optical +acoustic

Definition 2. Cover Object of a Stealth Aircraft.

The shape and geometry of the aircrafts structure as is modified by the incorporation of the hidden object.

airframe coating and structure + engine exhaust + radome + camoglage pattern + mufflers


Definition 3. Stego-Object of a Stealth Aircraft.

The convolution of the hidden object with the cover object.


Definition 4. Stealth Aircraft Capacity.

f(capacity) = f(avionics, electronics, ordnance, fuel)

signature management
controlled backscattering
avionics have emi and active emissions LPI radar has radome cockpit
fuel and ordnance have weight and spacial considerations
oxygen, cockpit,

Definition 5. Stealth Aircraft Security.

f(security) = f(rcs, ecm, IRemissions)

A radar system transmits energy towards a direction and then receives the amount of energy that is backscattered. This returned energy is called PRX, and is given by Equation




But the output of the radar receiver includes this signal plus ambient ther-man noise and receiver noise. Therefore we use a figure of merit called the signal to noise ratio (SNR) in order to define the receiver's sensitivity. In other words the ability of the receiver to output the backscattered signal correctly.A detection is defi ned by probability theory and exists when the incoming signal exceeds the detection threshold. A threshold is set that is a function of P`d and P`fa.

There is a relationship between SNR, P`d and P`fa.

P`fa can be reduced by advanced signal processign techniques. This means that R’ max can be increased





The heat emissions from the engines is present all the time.

receiver sensitivity
rcs is airframe, radomes, cockpit





Definition 6. Stealth Aircraft Robustness.

f(robustness) = f(environment, eccm, LPI, communications)

emissions management
stealth waveforms
where environment : the masking of the environment adaptation : that
effort to adapt the aircraft to the current environment conditions selfactivity :
generally all active emissions of the aircraft, electromagnetic and electrooptical.
small bird rcs equals to stealth aircraft rcs

the distance example verisimility issues
the speed of a flock of birds is not equal to the speed of a red force fighter jet as it approaches the blue force radar
flight tactics
Environment is atmospheric attenuation, clutter, terrain masking, electronic order of battle, classification usable sensitivity
C cover object H hidden object
R redundant part of the cover object or empty part of the aircraft
S stego-object

C + H - R = S





H = R






I hope I have been able to explain things better than I did in my last post. As always will look forward to the valuable insights that you guys provide.

Sorry, I am feeling a bit dumb today, you posted a chart describing stealth entropy, which is obviously a goal, but largely not totally applicable.

My understanding of entropy is a movement towards balance or neutrality, which I don't really think applies to stealth aircraft.

The engine bits will be hot and when flying at high altitude those parts of the aircraft not heated by friction with the air will be cold.

Entropy would suggest that the hot parts will loose heat faster than the cold parts and the cold parts will absorb the nearby heat and warm up and the object will become a more uniform temperature... but as long as the engines produce thrust and burn fuel and the ambient temperature above 10,000m is below minus 60 degrees C I really can't see that happening.

Ideally the perfect stealth design is a tiny sphere with a RCS that is uniform, but in practise that is a bad shape for a stealth aircraft as it is both unobtainable and also not very practical.

The real goal can be described using Helicopter canopies.

Think of an IR sensor directed at the canopy of a helicopter.

If it is daytime and the sun is behind the detector then with a smooth bubble canopy the IR sensor should easily detect the reflection off the bubble canopy of the sun from a very wide range of angles. It is not like the entire canopy is reflecting and magnified image of the sun, but for the helicopter it means it can be detected in IR from a very wide range of angles very readily.

Now look at a modern attack helos canopy... particularly the Mi-28N.

Relatively small flat panes.

From a very specific angle each pane will reflect a full sun view that is slightly brighter than the curved pane would generate because it is flat and not convex. Concave glass panels would create an enlarged sun that has its size and brightness magnified.

The point is that using IR as a guidance method is very useful against the curved bubble canopy because the coninuous signal can be locked on to and tracked. The flat panels mean occasionally you might get a flash of sunlight to let you know there is something there, but nothing continuous to track or target.

The purpose of stealth design is to redirect incoming signals in a different direction from that which they arrived at. There is also some absorption involved to reduce the signal strength as well.

The point is that so far no matter what the materials or the design, in practical terms you still have to make these things and as they age and perhaps the structure warps slightly all that effort and expense is wasted because the more stealthy you get the higher the tolerance level... if you are a 0.000001m RCS target and someone forgets to tighten a screw properly and it sticks up a few mms above the surface your actual RCS might become 0.1m.

Equally different radar frequencies have different properties... short wave are nice because very short waves show the shape of the target... a MMW radar can determine whether a vehicle is tracked or has a turret or not. Very long wave radar is uneffected by shape and will simply detect a presence or otherwise.

Modern US stealth is directed at high frequency radar because high frequency radar is widely used because of its accuracy in range so it is used for search radars and tracking radars and terminal guidance radars on missiles.

Higher frequencies can be fooled by thin coats of special materials, lower frequencies require thicker coats and shape has less effect.

Anyway the information about stealth entropy appears to me to be more related to vehicles using systems like Nakidka that help them blend in to their backgrounds, and would be less applicable to aircraft because of the speed they move at... and indeed the job they need to do, which likely involves using radar to avoid hitting the ground and detecting targets on land and sea and in the air.

BTW the last image you posted of the plane from the movie Firefox has an incorrect abbreviation translation.

LERX is more correctly Leading Edge (wing) Root eXtension, which is the extension of the wing at the wing root up the side of the aircraft. Sometimes called a blended wing it improves airflow and body lift, while generating an energetic vortex at high angles of attack which are usually used by the vertical tail fin to improve stability and control when pulling high AOA turns.

India and Russia going to sign biggest-ever defence deal worth $ 35 billion

NEW DELHI: India's quest for a futuristic stealth fifth-generation fighter, which will see the country spend around $35 billion over the next 20 years in its biggest-ever defence project, has zoomed into the decisive phase now.

India and Russia are getting all set to ink the full and final design or R&D phase contract for the 5th Gen fighter by this year-end or early-2013, say sources. It will again underline India's firm rejection of the US offer of its Joint Strike Fighter (JSF) or the F-35 'Lightning-II'.

IAF wants to induct over 200 stealth fighters from 2022 onwards, a senior team of Hindustan Aeronautics (HAL) engineers and IAF experts is going to Russia within a fortnight to ensure that the "full documentation and other work" of the earlier preliminary design contract (PDC) has been completed.

During his visit to Moscow last week, IAF chief Air Chief Marshal N A K Browne reviewed the performance of the 5th Gen fighter, called Sukhoi T-50.

While the Indian fighter will primarily be based on the T-50, it will be tweaked to IAF requirements.

India had inked the $295 million PDC with Russia in December, 2010. The R&D contract on the anvil is pegged at $11 billion, with India and Russia chipping in with $5.5 billion each.

"The three Russian T-50 prototypes have flown around 180 sorties till now. HAL's Ozar facility at Nashik will get three prototypes in 2014, 2017 and 2019...they will be flown by IAF test pilots," said a source.

"Russia has already given the draft R&D contract to us. It will include the cost of designing, infrastructure build-up at Ozar, prototype development and flight testing. So, India will have scientists and test pilots based both in Russia and Ozar during the R&D phase up to 2019. HAL will subsequently begin manufacturing the fighters," he added.

Interestingly, after first specifying the requirement for at least 166 single-seat and 48 twin-seat of these 5th Gen fighters, India is veering around to the view that it will go in for only single-cockpit jets now.

"Both F-35 and T-50 are single-seaters. A second cockpit will compromise the stealth capabilities by at least 15% apart from adding to the weight and reducing fuel capacity. Moreover, R&D costs could go up by another $2 billion for the twin-seater," he said.

IAF is confident the swing-role fighter will meet its future operational needs.

As a critical interim measure and confronted with a declining number of fighter squadrons, IAF also wants the almost $20 billion MMRCA (medium multi-role combat aircraft) project to acquire 126 French Rafale fighters to be sealed within this fiscal.

With 5th generation avionics the need for a second pair of eyes and hands in the aircraft should be greatly reduced.

Perhaps an enlarged strike model with side by side twin seats might be possible in 2020 or later that could be used as a Su-34 like strike model could be considered if there was enough demand.

Of course another model they could develop would be a CTOL carrier based version for Russian carriers, and perhaps as a replacement for the Mig-29Ks of the Indian Navy, though I would like to see a Tegas IV based on Indian capabilities after all this cooperation with Russia...

2 billion to develop a two-seater model, dear lord.

Very very interesting if India receives a test airframe as early as 2014.

TR1 wrote:2 billion to develop a two-seater model, dear lord.

Very very interesting if India receives a test airframe as early as 2014.

From the discussions that I had with people in the Indian Air force India will not get an FGFA test airframe before 2016. In the interim India will probably get the airframe of the T 50 . What suprises me most is that the number of officers in the IAF is declining & so are the number of pilots . How on earth can India go in for two seater aircrafts.

GarryB wrote:Sorry, I am feeling a bit dumb today, you posted a chart describing stealth entropy, which is obviously a goal, but largely not totally applicable.

My understanding of entropy is a movement towards balance or neutrality, which I don't really think applies to stealth aircraft.

Thanks GarryB .

Is it therefore fair to compare the stealth in fighter aircrafts to digital stenography because in digital steganography the information hiding process identifies the redundant bits of the cover image, which is usually of JPG type. These can be modied without destroying the cover object's integrity. The hidden message is placed in these slots.

Stealth and Steganography are related in the sense that both try to hide the presence of something, in the former case a military system, in the latter case usually a message or information.

Stealth attempts to conceal or hide the signature of the object/aircraft/vehicle from various types of sensors using shaping, materials, and coatings to absorb or deflect the signal used for detection away from the source.

If you can imagine being in a totally dark room and you have a very special torch that acts like a laser. A normal torch has a bulb but behind the bulb is usually a mirrored surface that focuses the light from the rear of the bulb forward in a narrow beam. The result is that there is a narrow focused beam from the lense behind the bulb but the direct light from the bulb shining out gives a reduced power light (because it is not focused and is spread over a wider angle) This special torch I am making up has a dark black cover over the bulb facing forward so only the narrow beam exits the torch front lense. (On a radar that beam is what you use to scan and track targets, the wide field emissions are called sidelobes and are useless for detection and tracking and is what Anti radiation missiles home in on to kill your radar).

Anyway... we are in a large totally dark room... if you point it at a person 50m awway then the light travels 100m and you should be able to detect and identify them. If that person picks up a full body length mirror however and holds it up so that it reflects the light directly back at you then they are easier to see because the mirror will reflect light back to you much better than the person or their clothing would.

If however the target turns the mirror 45 degrees to one side then you wont know there is something there.

A Jpeg image contains colour, brightness and hue information of each pixel group in an image. A bitmap (.BMP) contains information for each individual pixel which leads to large image files... a Jpeg uses maths to reduce the file size without loosing too much quality in the information.
The order that the information is stored is not set, so by varying the order of the information of a photo image you can hide short messages.

I have read that Al Quada have used another method of sending messages... they used POP email clients, so for instance fred in country x would open Outlook and set up a local account. Say "doUSHarm@terrorism.x" and then proceeds to write a draft letter. He would have preagreed on the account name and password with his contact in country y. His contact in country y would then open Outlook and set up his own pop account in that program using the address above with the correct password. He can then look in the drafts folder for the message... that has never been sent and he can write out his own reply and then save that as a draft. To cover this use of the system both users would send highly encrypted files that said "Hello... how is the weather?" and that sort of thing to distract anyone intercepting their messages. Using unusual words they might think it is code so after they encrypted it they will spend lots of time and energy trying to decode something that is meaningless chit chat.

So essentially as far as A2A armament goes

PAK-FA can carry 3x2=6 R-77 in internal bay and 2 SRAAM in side bay.

or

PAK-FA can carry 2 RVVBD and 2 R-77 plus 2 SRAAM missile in internal plys side bay


I think the 6 R-77 and 2 SRAAM is the same payload that F-22 carries

Eh, it is too early to say what it is defiantly.
We have not even see the definitive weapons for the PAK-FA, and internal arrangement can change considerably.

What is so far relatively certain is the central bays were designed around 4 Kh-58UKShK and R-37 sized weapons.

Side bays are very intriguing as well, a solution not seen on any "boxy body' stealth fighters so far.

I think if they develop new AAM thats not in the same class of R-77 then they have good chance to squeeze in 4 AAM.

But right now there are no new AAM being planned what ever is new development like R-77M takes the R-77 class forward.

The R-77 is a long slim missile with fairly narrow strakes and folding rear grid fins... it is ideal for internal carriage... that is what it was originally designed for in fact.

Will it be possible to retain the 3d thrust vectoring capability when the outlets of of the T-50 get a flattened stealth shape?

Hard to say for sure.

If it comes down to a choice I would think they will want to retain the extreme manouver capability over extreme stealth... the F-35 doesn't have a flat engine nozzle either.

KomissarBojanchev wrote:Will it be possible to retain the 3d thrust vectoring capability when the outlets of of the T-50 get a flattened stealth shape?

VLO shaped 3D TVC nozzle similar to a 2D TVC nozzle has not been designed till date. Neither the F 22 or the F 35 has such a feature. One way to achieve it would be the use of thick RAM treatments which would obviously result in some weight penalty .

It is important to note hear that the T 50 is being designed as a "Hunter Killer" which would detect other stealth or non stealth aircrafts at stand off distances & defeat them in a WVR combat.Had deep penetration capability been sought from the T 50 , then 3D TVC flat nozzles would have become important.

KomissarBojanchev wrote:Will it be possible to retain the 3d thrust vectoring capability when the outlets of of the T-50 get a flattened stealth shape?

According to Kopp ,it's hard to get 3D TVc with rectangular nozzle ,

Producing a 3D TVC nozzle design which has similar VLO shaping performance as the F-22A 2D TVC nozzle design is not a trivial task - there is no obvious simple solution to this problem. If the Russians have solved it, it would be a major advance in VLO nozzle design

http://www.ausairpower.net/APA-2010-01.html

3D TVC is doable. The X-36 tested a fluidic TVC nozzle which vectored thrust in the horizontal plane for yaw control. If you make the upper and lower exhaust panels moveable like on the F-22, you'd have a degree of 3D control. The disadvantage is that you can't shield the nozzles from the side for IR signature control, but you'd basically have a rectangular 3D TVC nozzle.

Otherwise, if you really don't care much about IR signature or rear hemisphere LO, you can use the paddle arrangement like the X-31 to get 3D TVC.

removed by me
Pak-Da reply in Pak-fa thread.

Indian Air Force Chief Outlines Fighter Jet Plans

An Indian negotiating team is heading for Russia to finalize details of the country’s participation in development of the Sukhoi T-50, also known by the Russian acronym PAK FA and by India as the Fifth Generation Fighter Aircraft (FGFA). India is providing half of the expected $11 billion cost to develop the aircraft, and earlier signed a preliminary design contract worth $295 million. The Indian development contract is expected to take six months to conclude, AIN has learned.

In an exclusive interview, Indian air force chief of staff Norman Anil Kumar Browne told AIN, “The contract incorporates our specifications, which are very demanding.” Browne drew a distinction between the FGFA version and the original PAK FA, three prototypes of which are already flying. “We still do not know what [our] final version will be like until we finish. What I can say is that it will be very different from the Russian version, including weapons, avionics and sensors.”

The PAK FA development program needs to complete 5,000 sorties, Browne said. “So we have work to do. The fourth prototype will fly soon,” he predicted. Government defense contractor Hindustan Aeronautics (HAL) will be participating in design and development. Following signature of the contract, HAL officials and Indian Air Force (IAF) test pilots will be based in Russia for seven years during the R&D phase.

“[The IAF] will get three prototypes for testing–the first in 2014/15, the second in 2017 and in 2019 the final one, which will be the version we order,” said Browne. Russian air force commander Gen. Victor Bondarev said recently that his service would receive production aircraft in 2015.

The IAF had “preliminary thoughts” about acquiring the Lockheed Martin F-35 in 2004/2005, but signed the MoU with Russia for the FGFA in 2007. “I am confident the F-35 will be a good machine. But now we have a concrete plan. We have crossed the time [line] and cannot commit to more than one project,” said Browne when asked whether India could still consider the F-35.

India initially planned to have 166 single-seat and 48 two-seat FGFAs, but recently it decided to take all 214 as single-seaters. AIN understands that the decision was driven by the fidelity of modern simulation, as well as the additional cost of building two-seaters.