My PAK-FA analysis

[saurabh]

There are huge differences between nozzles of F-22 and F-35. F-22 has four movable elements and F-35 has fifteen. F-22 has 2D TVC and F-35 has 3D. Triangular shape like F-22 can be opted by other engines as well but Russians have rejected it after testing.

I am sure that's not what I am looking for.
Thanks anyways.

 

[saurabh]

Can F-22, and for that matter any AC, detect other ACs on their data transmission and not radar?
Like suppose a stealth AC with its radar turned off, is out there, completely depending on AWACS. (A possible scenario for F22).
Its not possible to detect it with radar, no active detection nor passive. But since its in contact with AWACS, it will have to transmit some data. Can it be tracked? Or do AWACS act as a radio broadcasting station, and linked planes as simple receivers?

 

[Dron.ru]

Huge amount of information about PAK-FA/FGFA with foto: paralay.com/pakfasu.html

 

[sancho]

It would still remain to be seen. At what range even with AESA turned on. A T-50 would get a lock on an F-22. And though the F-22 may enter the battle space in passive mode. at some point it will turn it's radar on to get more exact tracking data. it will then transmit that targeting information to every aircraft and naval ship in the battle space. It is in effect a mini AWACS.

Just becuase the AESA on the T-50 has a long range does not equate to detecting an F-22 at that range. F-15 pilots report in red flag exercises that they have a hard time getting a radar lock with the F-22 directly in front of them.

You get me wrong, I am not talking about Pak Fa vs F22, I am talking about a different focus in the development and intenton to use the 5. gen fighters!

Let me change the example a bit, if US fighters enters Chinese airspace, they most likely will do it in passive mode and the full advantage of stealth right?
If Russias Pak Fa would enter Chinese airspace it seems like, it would prefer the active mode with it's radars turned on, because the situational awareness with those several radar arrays, combined the stealth capabilities (even if they don't look comparable to F22 at the moment),would still give a clear edge.

That's why I asked, if this could be the aim of Russian designers, putting the focus on situational awareness with high performance radar and IRST possibly, instead focus on best stealth capabilities like the US 5. gen fighters.

 

[Thomas]

@sancho

I understand what you are saying about situational awareness. Russia seems to rely more on sensors then stealth. Most likely becuase of the added expense and time delay in developing a aircraft more like the F-22. against 4th generation aircraft that will give it a decided advantage I'm sure.

To tell you the truth I doubt that the T-50 or F-22 will ever see combat against each other. Unless of course Russia or India decide to sell it to rogue states.

 

[Dron.ru]

"Given the phased implementation of the program FGFA, we can gradually reach the ratio of 50 to 50 (Russia and India)", - told reporters CEO Sukhoi Mikhail Pogosyan

 

[Thomas]

You get me wrong, I am not talking about Pak Fa vs F22, I am talking about a different focus in the development and intenton to use the 5. gen fighters!

Let me change the example a bit, if US fighters enters Chinese airspace, they most likely will do it in passive mode and the full advantage of stealth right?
If Russias Pak Fa would enter Chinese airspace it seems like, it would prefer the active mode with it's radars turned on, because the situational awareness with those several radar arrays, combined the stealth capabilities (even if they don't look comparable to F22 at the moment),would still give a clear edge.

That's why I asked, if this could be the aim of Russian designers, putting the focus on situational awareness with high performance radar and IRST possibly, instead focus on best stealth capabilities like the US 5. gen fighters.

Russia's tactics with the T-50 would most likely be no different then anyone else flying a stealth aircraft. Try not to be seen so you can strike first. If it starts pinging away at the start with it's AESA it will give away it's presence.

 

[1000VA]

Analysis From ausairpower.net released

Assessing the Sukhoi PAK-FA

 

[sancho]

To tell you the truth I doubt that the T-50 or F-22 will ever see combat against each other. Unless of course Russia or India decide to sell it to rogue states.

The see it the same way, only if PAF could get F35 as a replacement for their F16s, there would be a chance of fighting FGFA, otherwise it's more than doubtful.

Russia's tactics with the T-50 would most likely be no different then anyone else flying a stealth aircraft. Try not to be seen so you can strike first. If it starts pinging away at the start with it's AESA it will give away it's presence.

Will it? On the one hand it has radar detection probably in an aera of more than 200° with very long range, so even if an enemy fighter might get "some" signals of it though IRST, it won't be able to detect it correctly and its radar will useless against the stealth design in long range too. The Pak Fa insted, should be able to detect first and can engage first, or avoid the threat.
The same that US fighters will be able to do the same, with their radars on, but will be limited to frontal radar detection mainly and only passive detection in 360°. So when it comes to active detection, the Pak Fa could be better right?

Of course we can only speculate now, because too less is really known about the AESA radar, the L-Band arrays, or OLS 50. But this could be a reason why Russia went with this, lets say unusual 5. gen design, because till now 5. gen fighter meant, a small fighter, with the max of stealth capabilities, geared to be not detected. Pak Fa instead is a very big fighter, with maybe not that big focus on stealth, but more on the see first, shoot first idea of actuall western fighters.

 

[sancho]

"Given the phased implementation of the program FGFA, we can gradually reach the ratio of 50 to 50 (Russia and India)", - told reporters CEO Sukhoi Mikhail Pogosyan

Can you provide a source please!

 

[gambit]

Just a thought I had by reading this, aren't the Russians the same opinion like you?

Everyone does.

The US fighters focus mainly on not beeing detected by radar with increased stealth capabilities, but the Pak Fa (at least as far we have seen now), with a minimum of 5 AESA radar arrays in addition to IRST and only some stealth capabilites, seems to focus mainly on radar and detecting first right?

Just becuase the AESA on the T-50 has a long range does not equate to detecting an F-22 at that range. F-15 pilots report in red flag exercises that they have a hard time getting a radar lock with the F-22 directly in front of them.

At the risk of being redundant, I am going to rehash my previous explanation on how does a radar detect and finally recognize an object, be it a pencil or an aircraft or the Eiffel Tower.

Everything on a body is a 'scattering point'...

Radar imaging and multiple scatter-point localization

...reconstruct the spatial function of reflectivity of a target from the returned radar signals. Radar imaging is investigated from the point of view of multiple scatter-point localization.

The highlighted is significant and directly related to the illustration above. Basically...The receiver portion of the radar system process, or 'reconstruct', all the scattering points that reflected the transmitted signal, plot those points in a virtual 3D graph, assess if those points are in a cluster, or 'localization', and display the entire cluster as a 'dot' on the scope. The key phrase here is -- 'multiple scatter-point localization'. This effect MUST be constant over time as radar detection is at its core a stochastical process, fancy word for statistics and probability...

CiteSeerX — Nonlinear Stochastic Filtering Technique for Radar/Lidar Inversion

...joint estimation of backscatter and extinction coefficients from range/time noisy data under a nonlinear stochastic filtering setup. This problem is representativeofmany remote sensing applications such as weather radar and elastic-backscatter lidar. A Bayesian perspective is adopted. Thus, in addition to the observation mechanism, relating in a probabilistic sense the observed data with the parameters to be estimated, a prior probability density function has to be specified.

Note the highlighted. Everything points towards the fact that unless there is effective detection over time, even if the aircraft is violently maneuvering, ALL scattering points MUST remain localized in a format that the receiver can recognize as an 'aircraft'. Return to the illustration above. It is up to us, Americans or Russians or Chinese or Indians or Pakistanis or Marvin the Martian, to instruct the receiver, via algorithms, that if there is a cluster of scattering points in such-and-such manner over X timespan -- display it as a target. So clearly the problem here is how to resolve the variability of those scattering points as not only is the target in motion but so is the transmitter itself, like two boxers circling each other and as they do so, each will constantly see different angles of his opponent from different perspectives. Some scattering points will be lost from that virtual 3D graph and new ones will appear but the question is -- Are they as localized as the ones that disappeared? Inferior hardware can break target lock as perhaps the electronic engineering could not compensate for newly appeared scattering points that do not have the same power level as the ones that disappeared. Same for inferior algorithms. The combination of both inferior capabilities will result in an overall inferior system.

The reason why the human pilot can visually lock himself on to the F-22 but not his radar is because each TYPE of receiver processes the target thru different target characteristics, particularly in the EM region. The human pilot is one type of receiver. The radar system is another type. The infrared sensor is another type. Each has advantages and disadvantages. All are looking at the SAME TARGET. The human eye and the IR sensor are passive and does not have the ranging capability of the radar transmission, but the radar sensor is highly dependent upon those scattering points BEFORE it can determine, at those great distances, that there is a VALID target. The human sees constant valid targets, such as my G/F's shapely gluteus maximus for me. For the IR sensor, every body/object may emit different levels of heat but the greater the distance between sensor and target, the less details available and eventually all that remain is a single point of heat source, giving the IR sensor the distance advantage over the human eye. This is also why sensor suites that contains multiple sensor types are necessary but the negative here is cost as flight remains highly mass influenced. Given a mass limitation, the question is how to balance the sensor suite and the explosive warhead. More sophisticated missile avionics will require less explosive charge and perhaps some day we could have air-air missiles as purely kinetic kill type. The AIM-120 has a seven inch diameter and its solid fuel is very much an explosive. Straight into a jet engine exhaust or a body-wing root juncture and there would be no need for a separate explosive charge warhead.

High Off-Boresight (HOB) sensor system is essentially a combination of the human pilot sensor assisted by IR sensor. The 'off boresight' here is RADAR boresight, aircraft's and missile's radar boresights. The IR sensor, with its superior range over the human eyes, give the pilot general target direction. The pilot then focus his attention on that sector and launch his missile.

F16 Radar - Avitop.com

A boresight ACM mode is used for multiple aircraft engagement situations. The boresight uses a pencil beam positioned at 0-deg azimuth and minus 3-deg elevation to "spotlight" a target for acquisition.

Any fighter radar system is capable of having and entering the 'boresight' mode, this reduces the odds of distractions.

Boeing: History -- Products - Boeing Joint Helmet Mounted Cueing System

...airborne targets located at high off-boresight lines-of-sight relative to the shooter, providing a weapon with a short-range intercept envelope significantly larger than any air-to-air weapon in use today.

The HOBS system (the combination of JHMCS and AIM-9X) results in a weapon that can attack and destroy nearly any airborne enemy seen by the pilot. Additionally, this weapon can be employed without maneuvering the aircraft, minimizing the time spent in the threat environment.

Now it is up to the missile's own sensor suite to effect target detection and tracking, in other words, uses its own 'boresight' mode.

Nutation - Wikipedia, the free encyclopedia

Nutation (from Latin: nūtāre, to nod) is a slight irregular motion (etymologically a "nodding") in the axis of rotation of a largely axially symmetric object, such as a gyroscope, planet, or bullet in flight. A pure nutation is a movement of the rotation axis such that the first Euler angle (precession) is constant.

JSTOR: An Error Occurred Setting Your User Cookie

...remote sensing capabilities of entomological radar provide a solution to this seemingly intractable problem. We describe a novel, nutating-beam, vertical-looking radar with autonomous data analysis software.

What the antenna does in the 'boresight' mode is to 'nutate' or move in a circular movement. As the transmission impact the target, scattering points are activated, be they from an insect swarm or an aircraft. As a man, I would not be satisfied at looking at a Playboy Playmate of the Year just from the frontal view, no matter how beautiful she is. I would rather see her from as many perspectives as possible. Strip joint lap dances, anyone? Same for a radar seeking to create a target profile, hence the 'nutation' movement and that 'autonomous software'. But this is possible only as long as the target remain inside this 'nutation' or 'boresight' area.

So if the larger aircraft radar has a problem locking on to the F-22 even when it is within pilot's visual detection range and INSIDE the radar's 'boresight' area, what are the odds of the smaller missile radar having superior odds? The F-15's radar failed to effect target lock, not because it could not detect the F-22, but because the F-22's scattering points are insufficiently localized and the F-15's radar algorithms could not compensate because they were, to put it bluntly -- inferior. The F-15's radar could not create a valid target profile. What about chaff/flares discharged by the violently maneuvering F-22? How are the capabilities of the aggressor radar to compensate for the chaff distractors? It is not that difficult to imagine the F-15 pilots' frustrations when they can see the F-22 in front of them but their radars -- aircrafts' and missiles' -- could not.

There are those here perfectly content with their 'gut feelings' that the PAK-FA will be the F-22's equal and have disdain for sources and explanations that contradict those 'gut feelings'. What I presented are publicly available information. I hope interested readers will use appropriate keywords to find out more their own benefits.

If a F-22 is in passive mode. it is designed to detect anything with an electronic emission ( AN/ALR-94 one of the most closely guarded secrets on the F-22). Which means if an AESA radar is pinging away it will be detected.

The AN/ALR-94 has a range of 402km+

Exactly, but with the limitations that Gambit pointed out! My point was, that Russia seems not to count only on the stealth and passive detection capabilities and seem to focus on radar detection first, with passive detection and stealth capabilities in addition only.
So the most important point on Pak Fa might not be stealth, but possibly it's situational awareness.

Without AWACS support, would the F22 enter Russian airspace with radar turned on, or focus on beeing not detected with radar turned of and passive detection only?

It would still remain to be seen. At what range even with AESA turned on. A T-50 would get a lock on an F-22. And though the F-22 may enter the battle space in passive mode. at some point it will turn it's radar on to get more exact tracking data. it will then transmit that targeting information to every aircraft and naval ship in the battle space. making that T-50 or any aircraft or SAM site a big target. It is in effect a mini AWACS.

There is a Cold War tactic that NATO pilots often used, in training and against 'the commies', to avoid radar detection and I will use the F-111 as I am familiar with it and the fact that it was a strategic nuclear bomber. What the WSO will do is use inertial navigation to guide the aircraft to the radar protected airspace. Radar often assisted INS, but not at this time. Upon approach said protected airspace, the WSO will use his RWR to create a border of this radar boundary by having the pilot fly in a way that just touches the limit of the enemy radar coverage. At this furthest point, most radar returns will be classified as suspicious at best and often discarded as 'clutter' returns. Remember that distance affect power level, in transmit and echo, this is 'atmospheric attenuation' or loss. But as far as the RWR is concerned, it found a transmision at this maximum distance.

Aircrew coordination and system proficiency are crucial in finding any radar coverage gaps, and there always are gaps, then enter enemy airspace through those gaps. Of course, said gaps could be traps. That is the chance everyone must accept in war. Now imagine the F-22 and F-35 does this automatically with GPS instead of radar assist. Both aircrafts are fully capable of ingress/egress hostile airspace in passive mode. Any airborne or ground volume search radar will be mapped and avoided. Data links and sharing information will allow the entire force to have even more comprehensive radar intelligence as the force traverse enemy airspace. Gaps that are traps works best against 'non-stealth' aircrafts like the F-111 but not against extremely low radar observable aircrafts like the F-22 and F-35. What good is a trap if you cannot detect what is passing through the trap?

 

[Dron.ru]

Can you provide a source please!

Source (Russian news): infuture.ru/news.php?news_id=168

"С учетом поэтапного выполнения программы постепенно можно выйти на соотношение 50 на 50, - заявил журналистам генеральный директор АХК "Сухой" Михаил Погосян

Ratio of 75 to 25 is only the initial steps needed to reduce the time. Originally discussed the participation of 50 to 50, but the Indian side agreed to accept 25% of Russian technologies to accelerate the work. These 25% will be replaced by the Indian technology is already at the stage of mass production. These arrangements were originally made and is now gradually being implemented.

 

[amalakas]

Well ..some of us really love data ... don't they..?

Anyway . what plots won't tell you is that any radar system never has a guaranteed performance under all conditions, modes etc.

The detection range, tracking range, lock range. scan range, false echoes, look down modes, cluttering etc. is something that requires to actually get to use the radar and not read the manual and design plots...

There is the known case with some french radars not having such good performance on look down modes especially over pelagic environments.. NO ONE knew this.. it was actuall usage of the system that showed this..

We simply do not know how good the T50 radar will be..
What we do know is that 3rd and 4th ish generation aircraft cannot detect with their current systems when the F22 radar is tracking them..

Russians hope the same I guess.

Now when it comes to the T50 coming up against the F22, then again.. we simply don't know who's sensors will pick up a target first.. and if it does.. how will the weapons get a lock on ..

I argued with gambit that the russians have the upper hand on weapons because they can launch a volley of different guided missiles, the US currently only fields the aim 120 variants..

Perhaps the T50 is stealthy enough to not allow the AIM120 to get a terminal phase lock.. who knows...

and that also means that as Gambit pointed out, the IRST sensor as operated now, cannot give you range or vector, BUT.. an IR guided long range missile doesn't need all that info, as it only needs to be launched to the target and it will try to acquire on its own.. even if the missile misses during terminal phase will surely be picked up by the targets sensors causing the plane to start evasive actions further exposing itself to the plane that tracks it for further missile shots and now perhaps even from ER guided missiles...

 

[gambit]

Well ..some of us really love data ... don't they..?

In $God we trust. Everyone else please bring your data. By the way, $God is a variable so substitute one's own version. For the atheist, it would be undefined and there would be nothing higher to place one's faith other than data.

Anyway . what plots won't tell you is that any radar system never has a guaranteed performance under all conditions, modes etc.

True...But some systems are manufactured to tighter tolerances than others hence would come closer to ideal performance specs.

We simply do not know how good the T50 radar will be..

Then it is funny that so many here places so much hope on it, to the point where they dared to call it a 'game changer'.

Now when it comes to the T50 coming up against the F22, then again.. we simply don't know who's sensors will pick up a target first.. and if it does.. how will the weapons get a lock on ..

The body with the higher overall RCS at 100-200km distance will be detected first. Right now...All indicators seems to place the T-50 at a disadvantage.

I argued with gambit that the russians have the upper hand on weapons because they can launch a volley of different guided missiles, the US currently only fields the aim 120 variants..

Actually...Coming from a personal perspective in experience in weapons development and testing that involve a lot of data having a variety of air-air weapons is not a good thing. It usually indicate problems with sensor integration and overall aircraft technological development. Missiles are aircraft. The ideal goal is to have a single air-air missile effective at all flight regimes. Cuts down on deployment cost, from weapons storage to being on aircraft. We are working on that and given the US technological lead over the Russians...Better place your chips on our green tables instead of the Russians'.

Perhaps the T50 is stealthy enough to not allow the AIM120 to get a terminal phase lock.. who knows...

We do...Here is how it could turn out...

The above example is applicable to airborne platforms as well. What happens is that with data linking, BOTH aircraft and missile would be sharing target information but FROM DIFFERENT PERSPECTIVES. The aircraft with its radar and the missile with its own radar. Remember my explanation on how scattering points localization is composited into a target profile. In any fight, it is better to gang up on the enemy despite cries of 'No fair'. If we include the wingman's radar, we now have three different profiles for the same target. So even if the missile's radar is smaller and have inferior target resolutions than its parent, there will be ample correlation data among all three profiles to guide the missile to its target.

Dead meat for the Raptor, baby. And the Lightning II will strike it down as if Zeus himself deliver the bolt.

and that also means that as Gambit pointed out, the IRST sensor as operated now, cannot give you range or vector, BUT.. an IR guided long range missile doesn't need all that info, as it only needs to be launched to the target and it will try to acquire on its own.. even if the missile misses during terminal phase will surely be picked up by the targets sensors causing the plane to start evasive actions further exposing itself to the plane that tracks it for further missile shots and now perhaps even from ER guided missiles...

True...But as pointed out...If the larger F-15's radar have a difficult time with radar lock on the F-22 even when the F-15 pilot can see the F-22 with his own eyes, the smaller missile radar will have even lower odds. In radar detection, it is a combination of antenna aperature (dimensions), freq and power. There is no balance per se, only the understanding that if you adjust the characteristics of one element, you will affect detection capabilities in the other direction. The worst thing for a missile to have is a large beam and small antennas have large beams.

RADAR BEAM CHARACTERISTICS

Beamwidth varies directly with wavelength and inversely with antenna size. Radar systems that produce relatively small beam widths generally provide greater target resolution.

You compensate for that by using high freqs, such as the ghz X-band, but the downside to that is the F-22's body shaping is targeted at the X-band.

Despite my cheerleading for these 'stealth' aircrafts, I share the opinions of many pilots who have flown the F-16 and F-22 that in pure flying, as in aerodynamics exploitation, the F-16 is still supreme. There are two fighters that will catch the chicks' eyes: F-5 and F-16. I was fortunate enough to snag a backseat F-16D functional check flight (FCF) many years ago and it was orgasmic. Pulled continuous 9gs and I did not 'blow chunks'. We air refueled then got down to 100ft over the Gulf of Mexico. If there were any radar tracking us at that time, we went 'stealth' at that low altitude. Make working on these sexy aircrafts worthwhile.

 

[amalakas]

Hey Gambit

I was not lucky enough to hitch a ride in an F16, so I envy you there, I did catch one in an M2000 though..

In any case I wanted to comment on the missile situation.

The fact that the F15 radar couldn't get a lock on a stealth plane within visual range is irrelevant to russian planes.. their IRST sensor would get a lock on within visual range even if the russian radar was off, similar I think PIRATE would on the EF2000.

I don't subscribe to the AIM120 arguments.. I don't think multiple guidance versions are a limitation of design. I think its doctrine and modus opperandi..

Also I don't disagree that when a pair of F22 are pinging enemy aircraft and launch a volley of 120s the targeting data updates to the missiles will be more accurate and far more leathal, but still , the AIM needs to get terminal phase lock.. at least the revisions I worked with need to.. And still we don't know how stealthy the T50 is. In any case, in a proper long term engagement against a proper airforce fielding stealthy (if not stealth) aircraft I would be a bit uneasy simply using the AIM120 because the ideal environment cannot be taken for granted every time..