J-10 Thread IV

[sequ]

So it does the Irbis-E thing. In the end though it is not as a big of an advantage as people originally thought because it still lacks the EW resistance of proper AESA. J-11B with jammer pods can give it a hard time.

I wonder how feasible it is to convert the -B into the -C

 

[siegecrossbow]

I wonder how feasible it is to convert the -B into the -C

Even A could get AESA upgrade so I’d imagine it would be easier for B since the airframe is a lot more similar. Will it be as good as a fresh out of factory J-10C though? Probably not. There is a lot more to a plane’s avionics than just radar.

 

[Viperzero]

Not sure about the Hybrid AESA PESA thing. Hornetfinn at F-16.net (works on commercial AESA systems as a job) criticized the very concept of a Hybrid PESA.

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That's also totally misleading as every single PESA radar has receiver amplifier (low noise amplifier LNA) in tranceiver (or receiver). It's also impossible to put that LNA to antenna array itself as there the LNA would fry instantly when the radar is transmitting due to enormous power levels involved. In every fighter radar size PESA radar the LNA is outside and well away the antenna array and well isolated with duplexer and limiter switch. Radar receive signal in PESA goes first through phase shifters (there is some loss), then it goes through duplexer (there is loss), then through waveguide (there is some loss), then through receiver protection (some loss there too) and then to Low Noise Amplifier where the signal is amplified for the receiver itself. After that there are no meaningful losses in the system.

In AESA the signal goes to LNA much more directly and there is lot lower losses. First the receive signal goes through duplexer (with some loss) and then through receiver/LNA protection (with some loss). Then it goes directly to LNA where the signal is amplified. After that there are no meaningful losses in the system. Phase shifting is usually done after LNA which means one major loss item is avoided. Also there is LNA in each TRM which means there are 800-2000 LNAs in the system. In PESA there is only one LNA in the receiver (or tranceiver). LNA noise figure may be the same in both AESA and PESA, but in PESA there are more lossy items in the signal path. Modern PESA has about 3 dB higher losses than modern AESA in receive path and pretty much the same in transmit path due to same reasons. So AESA is more sensitive

Basically it's impossible to have hybrid of PESA and AESA. They work in very different ways and combining two different methods of operation is not possible. Only common thing is electronic beam steering and using phase shifting elements. Otherwise PESA is much more like MSA radar than AESA. I think it was Carlo Kopp who brought this idea that Bars and Irbis radars are somehow close to AESA in operation in the receive path with equal noise/loss levels and sidelobe performance. That's not possible at all like explained above. Losses are definitively higher in PESA and sidelobe performance can't be similar as there is only one receiving element vs. 800-2000receiving elements in AESAs. This way the errors decorrelate in multiple receiving elements and directivity, gain and sidelobe performance are all better.

The question has always interested me. I wish I knew the source of that image of the radar compared to the J-16 and J-20 radar.

as a for and against
AESA
Slanted back for LPI (never seen a PESA do this, but APG-80 and APG-79 do it)
Resembles J-10C radar
Contemporary with T/R module research
Air frame redesign seems unneeded for PESA (several Russian PESA were offered for J-10A in the 90s) J-10A probably has sufficient cooling for PESA.
Kinda strange to have a PESA only for an interm radar rather then just wait for AESA only a few years later. Seems more likely to have earlier AESA technology to gain experience (US did the same and mostly skipped PESA like China).

PESA
Prominent backend that resembles Type 1473 TWT
L-15 PESA does vaguely resemble J-10b radar Chinese articles seem to more often say it’s a pesa then AESA
Supposedly at the J-10B debut at golden helmets the J-11B dominated it. It’s not crazy for a mechanical scan radar to have better range when size is very different (J/APG-1 and APG-80 have less detection range then APG-70/63(v)1/PSP, APG-79 about the same) but supposedly the J-11B ECM gave the J-10B radar a lot of trouble. That’s way more likely with PESA, unless the J-10B software was in a very Immature state.

anyway it’s just a fun little question about the most mysterious member of the J-10 family.

 

[_killuminati_]

Not sure why those radar were so heavy, not all early AESA were heavy but it seems to have been a common issue.

Switching from liquid- to air-cooled?

 

[siegecrossbow]

Not sure about the Hybrid AESA PESA thing. Hornetfinn at F-16.net (works on commercial AESA systems as a job) criticized the very concept of a Hybrid PESA.

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The question has always interested me. I wish I knew the source of that image of the radar compared to the J-16 and J-20 radar.

as a for and against
AESA
Slanted back for LPI (never seen a PESA do this, but APG-80 and APG-79 do it)
Resembles J-10C radar
Contemporary with T/R module research
Air frame redesign seems unneeded for PESA (several Russian PESA were offered for J-10A in the 90s) J-10A probably has sufficient cooling for PESA.
Kinda strange to have a PESA only for an interm radar rather then just wait for AESA only a few years later. Seems more likely to have earlier AESA technology to gain experience (US did the same and mostly skipped PESA like China).

PESA
Prominent backend that resembles Type 1473 TWT
L-15 PESA does vaguely resemble J-10b radar Chinese articles seem to more often say it’s a pesa then AESA
Supposedly at the J-10B debut at golden helmets the J-11B dominated it. It’s not crazy for a mechanical scan radar to have better range when size is very different (J/APG-1 and APG-80 have less detection range then APG-70/63(v)1/PSP, APG-79 about the same) but supposedly the J-11B ECM gave the J-10B radar a lot of trouble. That’s way more likely with PESA, unless the J-10B software was in a very Immature state.

anyway it’s just a fun little question about the most mysterious member of the J-10 family.

Fun fact: J-11B EW could give Su-35 a lot of trouble too. There is a reason by J-10B didn’t go into mass production.

 

[Viperzero]

Switching from liquid- to air-cooled?

@Stealthflanker gave me an explanation

Probably because of the TRM construction which, might be conservative and use of cooling plate which are relatively thick. Also the TRM numbers. TRM alone is relatively light maybe 10 Grams but the mounting cooling plate might add some 50. 1500 TRM like one in APG-63V2 thus can weighs some 90 Kg.

And the AESA antenna can have additional structure to mount those TRM's and form the "skeleton" of the antenna Plus additional Plumbing for cooling and cabling for electrical power and data, also there might be some waveguide radar's main feed network (yeah current AESA does not have master oscillator and receiver in each TRM), things can easily pass 100-150 Kg.

That's kinda like 10-100 times heavier than conventional slotted array like APG-63V1 or APG-66.

There might even be relationship between weight of the cooling plate and maybe the TRM itself with power. Higher duty cycle TRM could be heavier than one which only need to emit, say 1-2 Watt.

Liquid cooling probably contributes to weight gain for the aircraft propped, I think this is a big reason for the weight difference between an F-16 block 50 and 60. However even though a lot of AESA are heavier than their MSA counterparts it’s not always the case. J/APG-1 is an early liquid cooled AESA and it’s lighter then APG-68, it’s listed weight is the same as APG-66!

Fun fact: J-11B EW could give Su-35 a lot of trouble too. There is a reason by J-10B didn’t go into mass production.

Not surprised at all, everyone slept on the J-11B when the Su-35 was catching the headlines, but it was probably always the best Flanker till the J-16 happened.

 

[aahyan]

https://twitter.com/i/web/status/1749689421161730540

 

[siegecrossbow]

https://twitter.com/i/web/status/1749689421161730540

Details?

 

[Deino]

https://twitter.com/i/web/status/1749689421161730540

Please don't get me wrong, but this again is much like these typical PDF "brahoo-posts" and some are already posting such posts:



As such, any official source or confirmation other than "brother I told you"!?

 

[Gloire_bb]

Slanted back for LPI (never seen a PESA do this, but APG-80 and APG-79 do it)

(1)Bombers: B1&B2.
(2)it isn't for LPI, it's for redirecting radar return at expense of changed coverage
(3)PESA can LPI.

Fun fact: J-11B EW could give Su-35 a lot of trouble too.

Doesn't sound especially plausible without proof far more reliable than usual posts.
Not per se (nothing implausible, though trouble is normal and expected result of work of a contemporary EW), but this is just not a field anyone related will be talking about, unless he is like really desert-level thirsty for tea.

Not surprised at all, everyone slept on the J-11B when the Su-35 was catching the headlines, but it was probably always the best Flanker till the J-16 happened.

This is a bold claim, esp. since J-11B is understood well enough.