J-10 Thread III (Closed to posting)

[tphuang]

Tphuang, can you make a judgement with this picture?

What do you think about all the talk over on the Chinese sites about the radar actually being PESA, what's your take on their credibility?

I don't know anything about this radar to actually comment on it.

It can't be circular because the way the J-10's nosecone is built precludes a circular radar.

But if you look at the AESAs, most of them have protruding elements, whereas in the case of the PESAs the planar array is flat, and if there's a feature in the array, it's a receding element.

Besides, the radar that most resembles the J-10B radar in surface features is the Irbis, not any of the AESAs.

If it can't be circular due to J-10B's nose cone, then that could be the evidence that J-10B is designed just for AESA. There is nothing wrong with that.

seriously, you can see protruding elements from this far out? Are you seeing protuding elements out of Zhuk-AE? Actually, can you tell any difference between Zhuk-AE and Zhuk-MSF? I can't.

As far as translucent material goes, we've seen a PESA that sufficiently resembles the radar we saw on the J-10B.

That IS the array in itself.

As far as the J-10B being the cheap fighter in the line-up, it's the high-low mix used by many other air forces. The J-7s and J-8s are legacy fighters, the J-10B provides most of the air combat capability, but when you need air superiority you take the J-11s and the Su-30MKKs for their superior BVR capability. If it beats the J-11s and the Su-30MKKs, sure, the F-16 beats the F-15 in dogfights as well, but from range the Su-30MKKs are more likely to pick off quite a few of the J-10s with BVR missiles before they even get into close range.

That's nonsense. J-11 gives plaaf additional long range strike missions, but there is no proof that it is better in A2A missions than J-10. In fact, it has always been the other way around until J-11B came around. And we have not seen evidence either way whether J-10 or J-11B is better in A2A missions. I would suspect that depends on the mission, the tactics and the supporting aircraft.

That's true, we're expecting around .5m^2 RCS on the J-10B, right? The J-11Bs are currently at 3m^2 RCS, and the Chinese are sufficiently dissatisfied with it that they want to upgrade and improve it. The radar on the flankers should have about 30% more range than the J-10B radars, independent of technology, based on size only, and a reduction of 10 times RCS results in a reduction of detection range by 50%.

Besides, loading on external weapons increases RCS significantly, so the RCS advantage will be more there if the fighters decide to jettison weapons and flee.

Still, one of the key advantages of the J-10 is its relative cost; the J-10B should cost around 40 million USD, the J-10A should cost around 27 million USD. There's no reason to install 10 million USD radars when that makes up a quarter of the plane's cost.

You have no idea the cost of the radar, or J-10, or J-10B or J-11B. And as mentioned above, J-10B and J-11B can both be better for different missions under different scenario. There is no reason J-10B can't be equipped with AESA to start off. But if they feel PESA is more mature right now, they should go with PESA. But as I said, I don't believe we can say conclusively one way or the other. Most of your arguments are very weak. And I think it's for the better that we all just drop this topic until there is more evidence.

 

[gambit]

If it can't be circular due to J-10B's nose cone, then that could be the evidence that J-10B is designed just for AESA.

There is NOTHING that says antenna shape is dependent upon array type.

 

[tanlixiang28776]

There is NOTHING that says antenna shape is dependent upon array type.

No. But we are basing it on known configurations of aircraft radars and the pattern they present.

 

[gambit]

No. But we are basing it on known configurations of aircraft radars and the pattern they present.

That still does not make your assumptions correct.

 

[tphuang]

There is NOTHING that says antenna shape is dependent upon array type.

Please try to read my comment again.

Inst is trying to say that the radar is not-circular because the nose is not circular. My rebuttal is that the nose was designed with the radar in mind. It was the original shape of the nose that gave us hint on what kind of radar will be under it. So if CAC deems that J-10B is designed to fit AESA radar and that the most optimal shape of the AESA radar is not circular, then it woul design the nose to not be circular.

Get it?

 

[gambit]

Please try to read my comment again.

Inst is trying to say that the radar is not-circular because the nose is not circular.

It is a wrong assumption.

My rebuttal is that the nose was designed with the radar in mind.

It is a wrong assumption.

It was the original shape of the nose that gave us hint on what kind of radar will be under it.

No...There is no such 'hint'. Antenna real estate, shape, and dimensions are independent of aerodynamic necessities evident by radome shape. By 'independent' it does not mean the antenna is not constrained by radome volume but that antenna real estate, shape, and dimensions are usually dictated from mission statements, in other words, if the main mission is volume search over other considerations, for example, then the antenna will shaped to produce a fan beam, regardless if the system is PESA or AESA.

So if CAC deems that J-10B is designed to fit AESA radar and that the most optimal shape of the AESA radar is not circular, then it woul design the nose to not be circular.

Get it?

See above.

 

[Quickie]

By 'independent' it does not mean the antenna is not constrained by radome volume but that antenna real estate, shape, and dimensions are usually dictated from mission statements, in other words, if the main mission is volume search over other considerations, for example, then the antenna will shaped to produce a fan beam, regardless if the system is PESA or AESA.
See above.

You gave an answer that goes against your own argument. The shape of the radar beamform of a PESA radar is pretty much determined by the arrangement of the radar elements, which in turn has to be a round shape if you intend to have the cone-shape radar beamform necessary for the usual missile fire control of a jetfighter radar. Not so for an AESA radar since the beamforms are independent of the shape of the radar elements.

 

[gambit]

You gave an answer that goes against your own argument. The shape of the radar beamform of a PESA radar is pretty much determined by the arrangement of the radar elements, which in turn has to be a round shape if you intend to have the cone-shape radar beamform necessary for the usual missile fire control of a jetfighter radar. Not so for an AESA radar since the beamforms are independent of the shape of the radar elements.

Nonsense...Even though we are talking about ESA radars, transmitter/receiver (T/R) array still has to obey the laws of physics because in an ESA system, beamforming and beamsteering works through exploitation of the principles of wave superposition. A round PESA array will produce a conical beam but so will a 'non-round' AESA main array if the correct amount of T/R elements are used in a subarray. The capability is called 'subarray partitioning' and 'subarray choreography'.

In the above example, if the software is sophisticated enough, see how many subarrays can you find in (b) and (c). The other two (a) and (d) are obvious enough. Fan beams are broad in the direction perpendicular to array's length. In both, there are subarrays that has conical beams and fan beams.

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A vertical fan beam is suitable for two-dimensional (2D) search radar making estimates of just the range and bearing of a target; such radars use, then, oblong reflector shapes (Fig. 6). A horizontally oriented fan beam might be used in a height-finding radar; its antenna, pointed to the azimuth of a designated target, nods vertically, scanning the narrow beam over the target to estimate its elevation angle.

It does not matter if the system is phased array or classical concave dish or planar, the laws of physics applies to China as well as everyone else. Beamforming is still dependent upon array shaping and in an AESA system, that array can be either a subarray or the main. If the latter, then the beam shape will be dictated by the array's shape, but if the array is a subarray, then the beam's shape will be dictated by the subarray's shape regardless of the main array's shape. That is the advantage of an AESA system that everyone desire.

 

[Quickie]

Nonsense...Even though we are talking about ESA radars, transmitter/receiver (T/R) array still has to obey the laws of physics because in an ESA system, beamforming and beamsteering works through exploitation of the principles of wave superposition. A round PESA array will produce a conical beam but so will a 'non-round' AESA main array if the correct amount of T/R elements are used in a subarray. The capability is called 'subarray partitioning' and 'subarray choreography'.

In the above example, if the software is sophisticated enough, see how many subarrays can you find in (b) and (c). The other two (a) and (d) are obvious enough. Fan beams are broad in the direction perpendicular to array's length. In both, there are subarrays that has conical beams and fan beams.

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It does not matter if the system is phased array or classical concave dish or planar, the laws of physics applies to China as well as everyone else. Beamforming is still dependent upon array shaping and in an AESA system, that array can be either a subarray or the main. If the latter, then the beam shape will be dictated by the array's shape, but if the array is a subarray, then the beam's shape will be dictated by the subarray's shape regardless of the main array's shape. That is the advantage of an AESA system that everyone desire.

Huh? Can you specify which part of my reply is arguing against which of the points in your post here?

 

[gambit]

Huh? Can you specify which part of my reply is arguing against which of the points in your post here?

When you said I contradicted myself.