JF-17/FC-1 Fighter Aircraft thread

[Mohsin77]

I am surprised that you think the IRST21 is some kind of marketing pitch.

I should've clarified:

The IRST21 development was to target the J-20.

The claim that the IRST21 was developed to deal with J-20s is what seems like a marketing pitch. I'm sure its a top tier IR imaging solution, and mounting it on a drop tank is genius. But IRSTs can't make Gen 4 competitive against Gen 5 by themselves, as I'm sure you already know. This myth was recently fueled by Russian and Indian sources. Russians claimed their Su-35s could target Raptors in Syria, while Indians claimed their MKIs can target J-20s over Tibet, using IRSTs... it's just propaganda.

Getting back to the topic, I still hope the Block III gets a podded IRST, as it does increase the tactical options and also speeds things up with IFF ROEs. Having 1 Thunder equipped with IRST in a group of 4 should be good enough for our use case, I would think. Integrating it on the airframe would actually be counter productive

 

[plawolf]

If the PAF is going with the podded IRST solution, than I seriously hope they added two extra hardpoints under the intakes instead of just the one rumoured.

That way for AA, they can carry an IRST and jammer; for AG, they can carry a targeting pod and ground mapping radar/Jammer.

I know they could easily send two planes and split the load out between them, but personally I think it would be better to pair blk3s with blk1s/2s if you were to pair them up, so all would benefit from the superior sensors and avionics of the BLK3 while bringing many more missiles to the fight.

That would also add redundancy to your force structure if you are going with larger formations, like a 4 ship with 2 blk3s and 2 earlier blks, such that if one of the blks was lost or needed to RTB, you still retain full capabilities whereas a split load would mean you will loose either your IRST or jammer in such a scenario.

That, or they develop a twin rack so you can carry a IRST and jamming/targeting pod on the same hardpoint. Although I’m not sure if that would also add to the wiring requirements for the hardpoint or if they could get away with some sort of splitter in the dual rack?

 

[Brumby]

I should've clarified:

The claim that the IRST21 was developed to deal with J-20s is what seems like a marketing pitch. I'm sure its a top tier IR imaging solution, and mounting it on a drop tank is genius. But IRSTs can't make Gen 4 competitive against Gen 5 by themselves, as I'm sure you already know. This myth was recently fueled by Russian and Indian sources. Russians claimed their Su-35s could target Raptors in Syria, while Indians claimed their MKIs can target J-20s over Tibet, using IRSTs... it's just propaganda.

IMO it is hardly comparable to equate the IRST21 capabilities to OLS-35 and OLS-30. They are at least 4 generations apart in technology.

IR detection is a lot more complex conversation than RF detection because the variables are much more. I think the general population has no clue to the science behind it. My impression is that when IRST is being discussed, the general view is that all IRST are similar. That is far from the truth.

For instance do you know what IR band is the proposed IRST pod for the JF-17? What material is used on the detector - HdCdTe, InSb, InGaAs, QWIP et al? What megapixel arrays are planned? Each of these properties have performance, cooling, power and cost considerations beside the atmospheric effect on IR detection.

As an example, the following is a Thales thermal imager with specific properties and range performance indicator depending on FOV selection mode.

Getting back to the topic, I still hope the Block III gets a podded IRST, as it does increase the tactical options and also speeds things up with IFF ROEs. Having 1 Thunder equipped with IRST in a group of 4 should be good enough for our use case, I would think. Integrating it on the airframe would actually be counter productive

As I said in an earlier post, I questioned the usefulness of IRST capability given the nature of PAF's threats.

Frankly I cannot think of an operational scenario that IRST will be meaningful for the JF-17. Maybe you can convince me.

 

[Mohsin77]

IMO it is hardly comparable to equate the IRST21 capabilities to OLS-35 and OLS-30. They are at least 4 generations apart in technology.

Fair enough, so maybe you can convince me how the IRST21 can be used by 4th gen aircraft to gain an edge over 5th gen aircraft, because I can't really see how that would work tactically.

The USAF is the domain expert in this arena, since they've been testing 5th gen longer than anyone. I'm sure they've tested Eagles equipped with Legion Pods (which includes the IRST21 sensor) against Raptors at Red Flag. But from everything that I've heard on open sources, the Raptors still dominate, unless they are placed at a severe disadvantage (and even then they do a lot of damage before dying.)

You'd first need to detect 5th gen from far enough to position yourself, and then get close enough to target them. And if they also have their own 4th gen 'missle trucks' you have to deal with those as well. Basically, IRST21s wont help by themselves against 5th Gen. You would need many other advantages on top of it.

Frankly I cannot think of an operational scenario that IRST will be meaningful for the JF-17. Maybe you can convince me.

Well, the traditional scenario for IRST is simply to verify radar contacts, which speeds up the decision cycle, especially in a heavy ECM environment, though not nearly as much as AESAs, which are much more useful here. But still, that is worth a few pods in every squadron.

The flashiest option which people love discussing, is actually the least likely to ever be used in combat, I think. The classic example is sneaking in your IRST equipped 4th gen aircraft, somehow magically, past all enemy radars, and launching Fox Twos... Yes, it is now possible to hunt only with passive sensors, and it does add to your tactical options, but success is unlikely, because 4th gen airframes will still get detected even with their radars off... You would first need to defeat all enemy AWACS for this to even be an option, IMO.... and even here, LPI AESAs are more useful.

 

[plawolf]

The issue with IRST is that in a legacy aircraft, you will have a much shorter detection range compared to a same or later gen opponent using his radar.

That means your opponent sees you first and either shoots you at long range, or manoeuvres so that by the time you are within IRST range of him, he is coming at you from a vector outside of your IRST field of view to take a much higher KP shot at shorter range.

Legacy aircraft generally have their IRST placed on top of the nose, because the designers recognise this issue, so the tactic would be for the fighter to flow low to try to use ground clutter to reduce enemy radar detection range against you. Flying low also means enemy aircraft would have the cold sky as a backdrop, increasing the effectiveness of your IRST.

5th gens generally have their IRST placed under their nose, because their stealth means they don’t need to fly low to avoid being outranged by enemy IRST. 5th gens with IRSTs were also introduced after ASEA radars, which makes ground clutter a much smaller issue.

Another benefit of placing the IRST under the aircraft is that it could allow augmented reality by syncing the IRST to pilot HMD movement and/or auto track enemy aircraft when outside of LOS of the cockpit feeding live imagery and/or directional guides to the pilot’s HMD. That would be one hell of a force multiplier capacity in a dogfight.

Depending on the IRST pod design and positioning, this might also be a capacity that could potentially be added to the BLK3, or maybe a future BLK4 JF17.

 

[Brumby]

Fair enough, so maybe you can convince me how the IRST21 can be used by 4th gen aircraft to gain an edge over 5th gen aircraft, because I can't really see how that would work tactically.

When we discuss 5th gen aircraft, I am speaking in the context of both signature and IR suppression. Both the F-22 and the F-35 incorporated features pertaining to IR management. I cannot say that is evidently true for the J-20 especially with the engine which is a primary IR signature source.

With the advent of the J-20 and its VLO shaping, detecting its presence becomes more challenging from the RF standpoint and so IR detection becomes an opportunity to increase the detection distance not available through the RF means. As I had previously said, the PAF doesn’t have such a requirement against the IAF due to its lack of a VLO platform.

The solution with the IRST21 (officially designated as AN/ASQ-34) is not just about the IRST itself but requires a collection of technological capabilities for it to be tactically feasible as a solution.

I am making the effort to explain it to both address your question and also to highlight the issue of IRST application is not simply podding the devise onto a platform as you may end up like the OLS-29 i.e. you can tick the box but not getting much else.

The USAF is the domain expert in this arena, since they've been testing 5th gen longer than anyone. I'm sure they've tested Eagles equipped with Legion Pods (which includes the IRST21 sensor) against Raptors at Red Flag. But from everything that I've heard on open sources, the Raptors still dominate, unless they are placed at a severe disadvantage (and even then they do a lot of damage before dying.)

You are mixing up a whole bunch of things which may not be necessarily true. Firstly, F-15Cs equipped with Legion pods probably have been tested with F-22s because the Legion pod is the means by which 5th to 4th communication is enabled as the F-22 and F-15 are meant to operate cooperatively. There is no public record of the F-15C installed with the Legion pod going up against F-22 and certainly even if it did, no outcome has ever been publicly disclosed. Your point about the F-22 demolishing the F-15C was based on more long dated encounters where clearly there were no Legion pods on the F-15C. We don’t even know whether that encounter included the F-15C having the AN/APG-63(V)3 AESA radar. The AN/ALR-94 onboard the F-22 can detect typical RF emission in excess of 450 km away. The question is at what range if it was LPD waveform.

Technologies don’t stand still – they always evolve. For example, we can speculate on what would be the outcome of a F-15EX installed with EPAWSS and Legion pod would fair against the F-22. I think the odds would narrow but the F-22 would still have the advantage due to relative RCS as ECM favors a lower RCS profile. I would speculate that EPAWSS has similar capabilities as the AN/ALR-94. In such an encounter both would not emit but how do you conduct OCA or DCA without emitting? Tactics would need to adapt depending on the threat.

You'd first need to detect 5th gen from far enough to position yourself, and then get close enough to target them. And if they also have their own 4th gen 'missle trucks' you have to deal with those as well. Basically, IRST21s wont help by themselves against 5th Gen. You would need many other advantages on top of it.

In tactics, the general philosophy is to build your engagement approach around your center of gravity and go after your opponent’s center of gravity i.e. the central note that can enhance overall force package and their delivery of intended effects. In the case of J-20 and its supporting “missile trucks” e.g. J-11s, the priority objective against such a force package would be to take out the J-20 because in doing so its center of gravity will be disrupted and its intended effects undermined. The J-11s with its high RCS will be a lesser problem.

As I said earlier the aim is to close the engagement range between the F-18 and J-20. This is just radar science. An AN/APG-79 is conservatively rated to detect a 1m2 target at 180 km. Translated say for the purpose of discussion, the J-20’s RCS is between 0.01m2 to 0.001m2, the detection range would be between 57 to 32 km. In contrast, the J-11 could probably be detected up to 320 km. The J-20 acting as a central sensor node could enhance the overall situation awareness of its force package through datalinks. The AN/ASG-34 under the right conditions is expected to double the detection range of the J-20 through its IR sensors as opposed to its radar, i.e. greater than 100 km. This is the outer range around where I expect future effective missile exchanges to predominate given ECM intervention.



The ability of the AN/ASG-34 to passively target at such a range is based on drawing together a set of capabilities including DTP--N, TTNT, MSI, CTP in addition to the IRST. Besides being highly dependent on atmospheric conditions, all IRST come with two major inherent weakness that need addressing. It does not automatically have ranging data which is a requirement for targeting and IRST are highly inefficient in scan mode i.e. search.

So how do those set of capabilities deal with those issues? IRST became popular in recent 20 years because of two developments; technological improvements in sensor optics and computational enhancements through IC. IRST are well known for producing high false alarm rate but continuous improvements in signal filtering has improved the situation. The processing brain of the Growler which does the signal processing of its EW is ported over to the Block III upgrade of the Super Hornet. The Distributed Targeting Processor-Networked (DTP-N) boost a 17 times improvement in processing speed against the existing Block II version.

Block I of the IRST21 program has already achieved the milestone in detection range. What is lacking to complete passive targeting is the ranging information which is the Block II development. There are two ways of achieving this. First is to conduct dynamic ranging via S maneuver or triangulation via a 2-ship formation. It should be noted that passive triangulation is very complex against a fast maneuvering target unlike against a static one. The program is currently bogged down with developing the complex ranging algorithm. Nevertheless a 2-ship triangulation is dependent on the exchange of real time data between a 2-ship formation and the Tactical Targeting Network Technology (TTNT) which is also ported over from the Growler will provide the necessary wide bandwidth throughput for near real time data exchanges as its latency is 6 times less than Link 16.

The third capability in this jigsaw is MSI originally known as Multi Sensor Integration. The program itself started in 2012 and recently renamed as Multi Sourced Integration. It is the format in which the different sensor tracks are fused and presented. Currently the program includes the correlation of data tracks from all off-board data from Link 16; RF tracks from AN/APG-79; IR tracks from AN/ASG-34; IFF signals; and ESM signals from AN/ALQ-214. The presentation is in single screen format with display symbology. This is a marked improvement in situational awareness from historical multi display of individual sensor tracks requiring manual collation. This presentation is useful to narrow the search box through track cueing given the natural inefficiency of IRST scans. The TTNT in conjunction will help to coordinate and reduce the search area workload by way of distribution between a 4-ship formation as the lowest tactical unit of deployment.

Finally, we get to the Common Tactical Picture (CTP) which builds a 3D picture of the tactical environment based on the track feed coming off the MSI.


Say in a hypothetical force on force engagement between Super Hornet Block 3 supported by Growlers vs J-20s mixed with J-11s. What would be the respective tactical deployment scenario? I think for the J-20 the question is whether it would exercise emission control or use its radar. The Growler being a SEAD asset by design would have superior ESM capabilities in terms of sensitivity and angular accuracy even though the AN/ALQ-214 itself is very capable. Any emission by the J-20 is likely picked up and that data track passed on via TTNT to the F-18 to cue the IRST for passive scanning. If the J-20 exercise emission control then its role of being sensor node is undermined. It should also be noted that the AN/ALQ-99 jamming pod of the Growler can jam from a distance of 400 km.

It is a different proposition if it was against the IAF as it doesn’t possess any of those capabilities that I described.

 

[Brumby]

Well, the traditional scenario for IRST is simply to verify radar contacts, which speeds up the decision cycle, especially in a heavy ECM environment, though not nearly as much as AESAs, which are much more useful here. But still, that is worth a few pods in every squadron.

The flashiest option which people love discussing, is actually the least likely to ever be used in combat, I think. The classic example is sneaking in your IRST equipped 4th gen aircraft, somehow magically, past all enemy radars, and launching Fox Twos... Yes, it is now possible to hunt only with passive sensors, and it does add to your tactical options, but success is unlikely, because 4th gen airframes will still get detected even with their radars off... You would first need to defeat all enemy AWACS for this to even be an option, IMO.... and even here, LPI AESAs are more useful.

As I mentioned before the requirement for IRST with the PAF and in particular with the JF-17 is just not there in terms of capability gap. Any IRST plan would be a solution looking for a problem.

We can easily demonstrate it by applying a couple of hypothetical scenarios. The first is a force on force between JF-17 Block 3 vs SU-30 MKIs. The JF-17 with AESA radar rated at 120 km against a 1m2 will detect the SU-30MKI at around 210 km. In contrast the Bars radar I estimate has similar detection range but assuming the JF-17 has a lower RCS at say 3 m2 would mean detection at 158 km. This gives the JF-17 a 50 km detection advantage. An IRST would not possibly improve this equation.

Take another scenario of Rafale vs JF-17 Block 3. The RBE2 has a detection range of 120 kms against a 1m2 target similar to the JF-17. The Rafale due to its lower RCS of say 1 vs 3 m2 will have a detection advantage of 158 vs 120 km. An IRST will not change this equation as the Rafale also has IRST. This outcome is inevitable as you are comparing a $120 million platform against a $30 plus million.

 

[Deino]

Guys... can we come back to the topic aka the JF-17??

 

[Mohsin77]

Guys... can we come back to the topic aka the JF-17??

I'll ask for some leeway here because I'm trying to understand the usecase for IRST for the JF-17, which means we have to discuss other 4th gen aircraft that use it already. And this also applies to the Block IIIs AESA, and how that would be employed. So it's all relevant to the JF-17.

 

[Mohsin77]

As I mentioned before the requirement for IRST with the PAF and in particular with the JF-17 is just not there in terms of capability gap. Any IRST plan would be a solution looking for a problem.

We can easily demonstrate it by applying a couple of hypothetical scenarios. The first is a force on force between JF-17 Block 3 vs SU-30 MKIs. The JF-17 with AESA radar rated at 120 km against a 1m2 will detect the SU-30MKI at around 210 km. In contrast the Bars radar I estimate has similar detection range but assuming the JF-17 has a lower RCS at say 3 m2 would mean detection at 158 km. This gives the JF-17 a 50 km detection advantage. An IRST would not possibly improve this equation.

Take another scenario of Rafale vs JF-17 Block 3. The RBE2 has a detection range of 120 kms against a 1m2 target similar to the JF-17. The Rafale due to its lower RCS of say 1 vs 3 m2 will have a detection advantage of 158 vs 120 km. An IRST will not change this equation as the Rafale also has IRST. This outcome is inevitable as you are comparing a $120 million platform against a $30 plus million.

I see your concern now (in bold), and it is valid. If you give a new tool to someone, the tendency is to find a way to use it, even in tasks where it doesn't belong. So I'll concede my point, even a podded IRST isn't really needed for the PAF at this point. It may end up over-complicating their training for no added benefit.

Quick word about the Rafale's RCS versus the JF-17... If it's really a 1m^2 vs 3m^2 difference, I'll be surprised. Nevertheless, the Rafales are the IAF's 'tier one' platform now, and that needs to handled with due concern by the PAF. It's not a trivial threat, by any means, even if there's only 30+ of them.

When we discuss 5th gen aircraft, I am speaking in the context of both signature and IR suppression. Both the F-22 and the F-35 incorporated features pertaining to IR management. I cannot say that is evidently true for the J-20 especially with the engine which is a primary IR signature source...................................

Wow, a lot of good intel as always Brumby. I wish there was more data on open sources for me to research some key aspects in play here. There's just not enough empirical data... For example, detection ranges against LPD/LPI emission sources are a complete unknown and are critical for this discussion. You're right that we have no idea what the results of any Raptor vs (Eagles+AESA+IRST) DACT training encounters may have been recently. They Navy just got its first 5th gen asset inducted into Top Gun, and I'm sure its Rhinos+IRST will be playing around with it now, but we won't really know anything until maybe 30 years from now, when 6th gen is already flying.... There's a lot of hypotheticals and unknowns here (AESA + Datalink + IRST + ECM + new BVRAAMs)... most of which have not been tested in combat.

I will say though, regarding your last point about Growlers going up against 5th gen aircraft, I'm skeptical of the efficacy of this solution. SEAD jammers are extremely sensitive to alignment, because they don't have the power output to blast a wide area. So I doubt Growlers would be useful against a fast moving aircraft in a fluid situation, let alone a 5th gen threats buzzing around the AO.