China Flanker Thread II

[Blitzo]

Wait. Don't the radars of F-15E and F-35 also have a 400-500km range? How do you judge the range of a radar? I know there are different measurements for different targets.

Actually I should have written it differently; Irbis E is just a much more powerful radar compared to older radars of previous generations whether it is Chinese, Russian, or Western.
I don't know what the range for F-35's APG-81 and F-15E's APG-70 are, but the F-22's APG-77 has a range of ~200 km against a 1m^2 target whereas Irbis E has a 400km range against a 3m^2 target which evens out more or less right.

The Chinese radars listed in the attachment that you commented on were all much older radar designs than the likes of advanced phased arrays like APG-77 or even Irbis E, so the discrepancy in range is to be expected.

So to answer your original question, it is the case that older radars tend to be less powerful than radars of new generations, and the radars listed in the diagram are all of an older design than equivalents like what is seen on Su-35S or F-22, F-35.

 

[thunderchief]

I don't know what the range for F-35's APG-81 and F-15E's APG-70 are, but the F-22's APG-77 has a range of ~200 km against a 1m^2 target whereas Irbis E has a 400km range against a 3m^2 target which evens out more or less right.

200 km against 1 sqm is something like 265 km against 3 sqm . Official range (on Tikhomirov website) of Irbis-E is 350-400 km for 3 sqm target on meeting course . Therefore, according to official data it is somewhat better then APG-77, which is not surprising since it is larger and somewhat younger (newer technology) .

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[SinoSoldier]

When people say Su-35 has a radar range of 400km, does that mean Chinese air-borne radars are simply not powerful enough?

The radars on the J-16 (and soon J-15) are believed to be similar performance-wise. Comparing a modern system to older generation radars doesn't prove much of a point.

 

[Akkarin]

200 km against 1 sqm is something like 265 km against 3 sqm . Official range (on Tikhomirov website) of Irbis-E is 350-400 km for 3 sqm

Can you please expand on that and explain/source it ?

Because I know nothing of radar, but If I naïvly assume that the rcs is a square and that both dimensions have the same resolutions, I get the following results:

1sqm@200km~1,031"

3sqm@264km~1,384"

3sqm@350km~1,021"

3sqm@400km~0,893"

So to me, what you claim doesnt seem realistic.

 

[b787]

The radars on the J-16 (and soon J-15) are believed to be similar performance-wise. Comparing a modern system to older generation radars doesn't prove much of a point.

that is unlikely, just by physics, electricity is transformed into electromagnetic waves, more voltage equals more power density, the Chinese aircraft need a lot of electricity to achieve 400km of range, or wires and materials that waste electricity very little and do not get fried with excess voltage, basically 117 engines will render old Al-31s and even WS-10s into less powerful electricity generators, having two 117s means 30 tonnes of thrust and a lot of electricity generation.

if J-16 wants that power will need like an E-3 additional electricity generators

 

[SpicySichuan]

The radars on the J-16 (and soon J-15) are believed to be similar performance-wise. Comparing a modern system to older generation radars doesn't prove much of a point.

View attachment 11745
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View attachment 11749

Ummm...where did you get these information. So that means for modern radar, you track an old Su-27 (RCS=15m2) when the latter is 500-600km away? So basically if the J-20 come into service in the early 2020s (assuming WS-15/10G problem is fixed), while the Taiwanese use less powerful AESAs for their F-16s, the J-20s and J-16s can function like mini AWACS before choosing which target to engage? And basically is this what the USAF can do with China and Russia today?

 

[b787]

The radars on the J-16 (and soon J-15) are believed to be similar performance-wise. Comparing a modern system to older generation radars doesn't prove much of a point.

The traditional airplane: electrical and pneumatic systems
On a traditional airplane, power is extracted from the engines in two ways to power other airplane systems:

• Generators driven by the engines create electricity.
• A pneumatic system “bleeds” air off the engines to power other systems (e.g., hydraulics).

Modern jet engines are very efficient, but removing that high-energy air robs them of some energy. A pneumatic system means that the engines produce less thrust, so they must be bigger, work harder and use more fuel. The system also means more weight, fuel burn and maintenance due to the heavy ducts and equipment needed to manage that hot air.

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Thus Irbis has two very powerful engines powering it, WS-10s or Al-31 will be less likely to be able to do it, thus is not likely J-16 will have a radar as capable as Irbis.

 

[The Philosopher]

Well these new aircraft and certainly the Su 35 super flanker will give China an edge over any country In the region on the u.s with the f22 would be hard to deal with

 

[thunderchief]

Can you please expand on that and explain/source it ?.

Basic concepts of RCS and radar range . Signal received by the radar is inversely proportional to the fourth power of range and directly proportional to the RCS of target :

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350-400km for 3sqm target is a number given by Tikhomirov for Irbis-E radar, as I said before .

 

[latenlazy]

that is unlikely, just by physics, electricity is transformed into electromagnetic waves, more voltage equals more power density, the Chinese aircraft need a lot of electricity to achieve 400km of range, or wires and materials that waste electricity very little and do not get fried with excess voltage, basically 117 engines will render old Al-31s and even WS-10s into less powerful electricity generators, having two 117s means 30 tonnes of thrust and a lot of electricity generation.

if J-16 wants that power will need like an E-3 additional electricity generators

You're forgetting things like software optimization, systems design and optimization, beam frequency and duration, the effects of shrinking element sizes on waste and efficiency, etc. Not saying that 400 km range is reasonable, but it's not far outside the realm of possibility, tentatively speaking, if some other factors, adjustments, and compromises are made.