J-20 5th Gen Fighter Thread VIII

[Gloire_bb]

Why is EOTS a step back? It allow for Search and track without opening the radar

All IRST do, that's their job. But for the current system - it does so in the best band specifically for BVR a2a, and does so with a larger mirror(pretty straightforward here: larger mirror - more light gathered - much better).

Mid-IR produces sharper picture (good for a2g and adverse conditions identification...but not too far) and detects hotter sources very well(reheat plumes/halo, etc).
Far infrared is more boring picture-wise, but it much better sees friction-heated edges&surfaces (subsonic flight, frontal hemisphere) from extended ranges. It is also far less susceptible to atmospheric scatter(sees further, better sees through adverse atmospheric conditions).

Mid-infrared systems make sense for WVR (4th gen Chinese, all Soviet/Russian, French "balls") - but since EOTS' FoW is almost exactly opposite to the pilot's, it most clearly isn't made for that. It can help, sure - but they would've placed it above the radar dome if it had been a goal.

 

[sr338]

All IRST do, that's their job. But for the current system - it does so in the best band specifically for BVR a2a, and does so with a larger mirror(pretty straightforward here: larger mirror - more light gathered - much better).

Mid-IR produces sharper picture (good for a2g and adverse conditions identification...but not too far) and detects hotter sources very well(reheat plumes/halo, etc).
Far infrared is more boring picture-wise, but it much better sees friction-heated edges&surfaces (subsonic flight, frontal hemisphere) from extended ranges. It is also far less susceptible to atmospheric scatter(sees further, better sees through adverse atmospheric conditions).

Mid-infrared systems make sense for WVR (4th gen Chinese, all Soviet/Russian, French "balls") - but since EOTS' FoW is almost exactly opposite to the pilot's, it most clearly isn't made for that. It can help, sure - but they would've placed it above the radar dome if it had been a goal.

I don't fully understand. Are you saying EOTS has less range than IRST?

 

[Gloire_bb]

I don't fully understand. Are you saying EOTS has less range than IRST?

Comparing two terms like this (IRST and EOTS) is wrong. IRST and EOTS are types of devices, closely interlocking ones at that.
But on a pair of J-20 and F-35 EOTS - if our understanding of that J-20 sensor is is true, yes.

Against meaningful air targets - yes, it will give detections much further and more reliably.

 

[Blitzo]

I have a question regarding the J-20's EOTS. Why is it only forward pointing while the F-35's EOTS is 360deg?
If you see the pics, the rear half of the J-20s EOTS is obscured.

The J-20 is more aerial combat oriented than a generalist like the F-35 so the current approach is sufficient for the time being. China is working on a full blown solution similar to what is used on the F-35, however. There was a paper on this in 2022. Wouldn’t be surprised if we see a fully transparent EOTS on production level WS-15 J-20.

Comparing two terms like this (IRST and EOTS) is wrong. IRST and EOTS are types of devices, closely interlocking ones at that.
But on a pair of J-20 and F-35 EOTS - if our understanding of that J-20 sensor is is true, yes.

Against meaningful air targets - yes, it will give detections much further and more reliably.

I don't think we currently have any understanding of what specific bands the J-20's EO IRST operates at. The only thing we know is that the rear hemisphere is opaque so it likely isn't intended to track targets in the rear hemisphere.

I also do not think calling a sensor as "EOTS" is useful because ultimately it doesn't tell us much about what such a hypothetical sensor setup for J-20 would mean.
I.e.: does it mean having an EO IRST with rear hemisphere coverage as well as more downwards/air to ground coverage
Or does it mean having the above while also having a laser spot tracker that is useful for A2G roles?
Or doe it mean the above two while also having a laser designator which is essential for A2G roles?
Does it mean having a ROVER-esque function to transmit the sensor feed onto ground force tablets and consoles to enable better coordination of CAS missions?

So on and so forth.

 

[Gloire_bb]

I don't think we currently have any understanding of what specific bands the J-20's EO IRST operates at. The only thing we know is that the rear hemisphere is opaque so it likely isn't intended to track targets in the rear hemisphere.

i was careful to mention before that it's "current state of understanding" - it's the only meaningful combination within given format. Perhaps still not clear enough.

Otherwise, either position(below) or cover don't make sense - at a current level of knowledge.

 

[Blitzo]

i was careful to mention before that it's "current state of understanding" - it's the only meaningful combination within given format. Perhaps still not clear enough.

Otherwise, either position(below) or cover don't make sense - at a current level of knowledge.

Yes, I saw that's what you wrote. I'm disagreeing that our "current state of understanding" is what you described.

I think our current sate of understanding of J-20's sensor is that it is some type of EO IRST, which likely is not intended to cover the rearmost hemisphere, and likely intended for the A2A role primarily.

But beyond that, based on our current state of understanding I don't think we can make any comment as to how well J-20's EO IRST performs against aerial targets comparatively either to F-35's EOTS, or to a hypothetical more multirole replacement sensor for J-20's current EO IRST. It is that part which you wrote which I disagree with.

 

[Gloire_bb]

Makes sense.

However, given clear connection b/n J-20 requirements and ATF as it was in ~late 1990s (as inspiration), and that the latter had a very much similar solution(externally) - IMHO it's a reasonable continuation of thought train. It gives us enough to change where we look for analogy - from F-35 EOTS/Sniper lineage to AN/AAS-42, IRST21(Legion), etc.

And, in turn, it is no less fair than many basic assumptions on Chinese AESA radars we make, on a similarly flimsy basis.

 

[_killuminati_]

Depends on the scale of the system - pilot preparation is highly scalable. WW2 and Cold War air forces mustered tens of thousands of fighter pilots.

Flying in the airforce was a lot easier back then when avionics were menial. All you really needed was to understand the physics of flying, dropping a bomb, tactics & maneuver training. Now however, you must know in detail about the avionics, electrical systems, physics of the missiles, how to operate the radar, aerial refuelling, etc, in addition to everything from WWII era.

 

[minime]

Flying in the airforce was a lot easier back then when avionics were menial. All you really needed was to understand the physics of flying, dropping a bomb, tactics & maneuver training. Now however, you must know in detail about the avionics, electrical systems, physics of the missiles, how to operate the radar, aerial refuelling, etc, in addition to everything from WWII era.

That's why AI is the next pinnacle.

 

[_killuminati_]

That's why AI is the next pinnacle.

That is true, the computer will do most of the work. But I'm sure the pilots are required to know what's happening behind the computer, fail safe procedures. Just as an accountant must know how to do everything manually even though most of the work is done by software.