PLA AEW&C, SIGINT, EW and MPA thread

[enroger]

Once a frequency has been input into the equation, even if unknown, the ratio remains linear. 1 m2 at 480 km ratio claim thus remains linear even at far lower RCS, as the frequency doesn't change.

Of course we don't know what wavelengths new AEW planes use but it's certainly plausible they've moved to longer wavelengths. Both for counter stealth (primarily) and for lower power usage (secondary). A slight indication of that might be the fact KJ700 uses a single rotating array, instead of 3 fixed arrays of the KJ500. In so, said single array can take up almost the full diameter of the rotodome and is thus more suitable for a somewhat longer wavelength, while still keeping array resolution manageable.

I meant claimed rcs figure for fighter, a stealth fighter claimed to have 0.001m2 rcs probably is specified to x-band, that figure could vary orders of magnitude depending on wavelength.

Yeah the new single rotating array going for longer wavelength makes sense, hopefully that is the case.

Also I feel the claimed figure is a bit strange, I remember many years ago KJ-2000 was claimed have detection range of 400km against fighter size target (back then it could mean rcs of 3 to 10m2). With such huge improvement in radar technology over the years I expect the stats to improve a lot more than that. Maybe it is another case of China deliberately understating things for all we know

 

[latenlazy]

I meant claimed rcs figure for fighter, a stealth fighter claimed to have 0.001m2 rcs probably is specified to x-band, that figure could vary orders of magnitude depending on wavelength.

Yeah the new single rotating array going for longer wavelength makes sense, hopefully that is the case.

Also I feel the claimed figure is a bit strange, I remember many years ago KJ-2000 was claimed have detection range of 400km against fighter size target (back then it could mean rcs of 3 to 10m2). With such huge improvement in radar technology over the years I expect the stats to improve a lot more than that. Maybe it is another case of China deliberately understating things for all we know

It’s not all about range. Resolution and signal quality also matters, especially for sustained tracking and even the ability to get a long range lock.

 

[enroger]

It’s not all about range. Resolution and signal quality also matters, especially for sustained tracking and even the ability to get a long range lock.

True, but detection remains the number one priority, without it there is no talking of resolution or tracking.

Here's a scifi thought, what if dual-band radar on the same array? Long wavelength for detection, short wavelength for high resolution tracking. It is probably not that scifi for China now

 

[Gloire_bb]

Here's a scifi thought, what if dual-band radar on the same array? Long wavelength for detection, short wavelength for high resolution tracking. It is probably not that scifi for China now

Why not separate though?

 

[enroger]

Why not separate though?

No definitive reason except it would be neat if the dual-band radar can be integrated into the same array in the dish. If they were separated I suppose there would need to be one array on the dish, another array on the main body of the aircraft

 

[Stealthflanker]

Here's a scifi thought, what if dual-band radar on the same array?

Space might make this concept kinda hard to realize tho. There might also be compromise in scanning angle as you know. You have to "share space" between two bands. The longer band will have larger antenna element, smaller one of course will be smaller, this bring spacing issue for the shorter band as the size of the longer band's element might not necessarily allow the smaller band to have proper Half wavelength spacing for achieving the same amount of FOV as the longer band.

Such will result with reduction of scan angle (e.g from 120 to smaller say 100 or even 90 degrees). The higher band radar cannot cover the same volume as the longer band.

The other concern would be weight as obviously the TRM for L-band and the higher band will be different design. The other will be possible interference between the elements, and to provide isolation between the L and higher band. This could be solved perhaps by having GaN switch which can take relatively large "power leak" and to design higher band element with opposite polarization compared to the lower band (e.g Vertical for L-band, Horizontal for higher say, S-band) but there will still be spacing issue.

 

[ACuriousPLAFan]

The C919 only has a MTOW of ~80k tons and this is unideal for some special mission aircraft. For reference, E-3, RC-135, and KC-46A are all in the 150k tons MTOW class.

The C929 is likely in the ~200-250k tons class, so clearly the 120-150k range won't be fulfilled anytime soon. We're looking at 3 digits of combined airframes here (tanker, ISR, transport, maybe AEW&C, and perhaps even MPA and EW), so even without being used as an airliner, the demand is visible. The plane could have some civilian applications nonetheless, such as being used for transport and cargo.

Keep in mind that the upcoming Y-30 will also play a key role in being a platform for many special mission aircraft.

That's where the rumor of a 200k ton mtow twin jet comes in, transport aircraft is suboptimal for AEWC and other special mission aircraft that require a large complement on extended duty.

Just some slight corrections - I believe you guys meant 80 tons, 150 tons, 200 tons and 250 tons respectively.

This is because 80k tons would be as heavy as Fujian CV. And 200k tons would be as heavy as certain cruise ships and container ships.

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Speaking of which - An aircraft platform with an MTOW of ~120 tons would be roughly in the category of the Boeing 757, whereas an MTOW of ~150 tons would be somewhat larger.

I would suppose a 21st-century 757-sized platform for next-generation special mission aircrafts would be a sweet spot.

In the meantime, a 200-ton platform is rather too big for many of the military applications, and is close enough to the category of the Boeing 787 and Airbus A330neo. Might as well just go bigger with a military counterpart to the COMAC C929.

As for the Y-30 - If the aforementioned platform does exist, then the Y-30 would most certainly be relegated to its primary role as a tactical airlifter, bar certain special mission roles (e.g. special operations) that would be unviable for the aforementioned platform to conduct.

 

[sunnymaxi]

Just some slight corrections - I believe you guys meant 80 tons, 150 tons, 200 tons and 250 tons respectively.

yes.

C919 MTOW is 78.5 tons
C929 MTOW is 247 tons

and regarding 200 tons platform.. it will be too large, almost the Y-20 category class machine.. the rumors are about 140-150 tons twin Engine powered platform. less costly as compared to Y-20.

 

[00CuriousObserver]

Just some slight corrections - I believe you guys meant 80 tons, 150 tons, 200 tons and 250 tons respectively.

Because 80k tons would be as heavy as Fujian CV. And 200k tons would be as heavy as certain cruise ships and container ships.

---

Speaking of which - An aircraft platform with an MTOW of ~120 tons would be roughly in the category of the Boeing 757, whereas an MTOW of ~150 tons would be somewhat larger.

I would suppose a 21st-century 757-sized platform for next-generation special mission aircrafts would be a sweet spot.

As for the Y-30 - If the aforementioned platform does exist, then the Y-30 would most certainly be relegated to its primary role as a tactical airlifter, bar certain special mission roles (e.g. special operations) that would be unviable for the aforementioned platform to conduct.

In the meantime - A 200-ton platform is rather too big, and is close enough to the category of the Boeing 787 and Airbus A330neo. Might as well go bigger with a military counterpart to the C929.

Darn, too much Fujian watching lately.

I should have been more careful about uncertainty in my comment on the Y-30. My reasoning that the C919 is unlikely to have military applications anytime soon for obvious reasons. Depending on the weight class of the Y-30 compared to the hypothetical platform (say, 80 tons vs 140 tons), then the Y-30 could potentially satisfy certain special mission roles, such as MPA, even if the larger platform exists

Considering the extensive variants development of the Y-8 and Y-9, personally I would be surprised if the Y-30 didn't have special mission variants. Being a propeller transport may also bring its own benefits.