Russian Su-57 Aircraft Thread (PAK-FA and IAF FGFA)

[Stealthflanker]

This is very likely.Under the same technology, the number of TRM will affect the ability of AESA, H036-1-01 has only 1552 TRM.[AN/APG-81 has 1676 TRM] There is no inevitable relationship between capacity and age,such as J20/J35 still uses engines that lag behind US for two decades or more.This is similar to the problems encountered by Russia in the electronics industry

Yeah, but this require more insight. It is true that more TRM = more performance. but the differences doesnt seem to be many.

The following is a simple rules of thumb of comparing ranges of AESA by just module numbers.



Now we have APG-81 vs N036. Assuming same conditions and same power rating.. the advantages of 1676 TRM would be :

Rf=((1676/1552)^3)^(1/4)
Rf=1.1

Where Rf is Range factor.

So the advantage is 1.1. Thus if N036 can detect target at 100 km.. the APG-81 will detect the same target at 110 km. I'm kinda wonder tho if 10 km advantage would be significant. Especially assuming air combat where the participants will move rather fast. If one wish to gain advantage like say, twice the detection range or a factor of 2. It would require 3910 TRM.

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Considering that PLAAF has bought Su35 and Irbis-E, and that the two authors of the paper are senior engineers and researchers at CAC, I think this is very credible.

Yes. although i think some factors like Radar and especially RCS needs further explanation.

 

[panzerfeist1]

@Qian CDer

The Apg-81 was stated to see an aircraft from 200 miles away, I am assuming its an F-16 that the pilot billie flynn was using for reference.

@48:30

the only best source we have for the apg-81 performance is words coming from a pilot. Also there was already news that the Radar got upgraded to N036M just use yandex image translate.

 

[Anlsvrthng]

Yes, the paper thinks that Su75 will be similar to F35 at this point.

The empty weight vs engine thrust is approx the same for F-35 and Su-57 with the current engines.

With the new engine the Su-57 will be superior to the F-35 .

 

[Anlsvrthng]

Yeah, but this require more insight. It is true that more TRM = more performance. but the differences doesnt seem to be many.

The following is a simple rules of thumb of comparing ranges of AESA by just module numbers.

View attachment 81694

Now we have APG-81 vs N036. Assuming same conditions and same power rating.. the advantages of 1676 TRM would be :

Rf=((1676/1552)^3)^(1/4)
Rf=1.1

Where Rf is Range factor.

So the advantage is 1.1. Thus if N036 can detect target at 100 km.. the APG-81 will detect the same target at 110 km. I'm kinda wonder tho if 10 km advantage would be significant. Especially assuming air combat where the participants will move rather fast. If one wish to gain advantage like say, twice the detection range or a factor of 2. It would require 3910 TRM.

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Yes. although i think some factors like Radar and especially RCS needs further explanation.

Problem is the increase the TRM number decrease the wavelength, that in turn decrease the effect of the edge scattering ,and makes the edge RAM more effective.

And there are countless other parameters, like steerable radar on its own increase the detection range by 18% at 60 degree off boresight, if the radar aperture say 30% bigger then it means 6% bigger range.

 

[Stealthflanker]

Problem is the increase the TRM number decrease the wavelength, that in turn decrease the effect of the edge scattering ,and makes the edge RAM more effective.

What are you talking about ?

And there are countless other parameters, like steerable radar on its own increase the detection range by 18% at 60 degree off boresight, if the radar aperture say 30% bigger then it means 6% bigger range.

Parameter of what ? What are you comparing to ?

 

[Anlsvrthng]

What are you talking about ?



Parameter of what ? What are you comparing to ?

? 1. electromagnetic radiation.

2. And there are countless other parameters, like steerable radar on its own increase the detection range by 18% at 60 degree off boresight, if the radar aperture say 30% bigger then it means 6% bigger range.

It means, if there is two identical radar in every paramater APPART from one is bigger by 30% and steerable then the the later one will have 25 % bigger range 60 degree steered to the side.


It means that the F-35 radar needs to be 3 times more powerfull than the su-35 radar to provide the same performance in all angle.

It means that a bigger , steerable radar in a bigger, more powerfull airframe, with more fuel reserve for cooling could give same or bigger performance than a more complicated and advanced radar with smaller dimension in a smaller airframe.

 

[Stealthflanker]

? 1. electromagnetic radiation.

2. And there are countless other parameters, like steerable radar on its own increase the detection range by 18% at 60 degree off boresight, if the radar aperture say 30% bigger then it means 6% bigger range.

It means, if there is two identical radar in every paramater APPART from one is bigger by 30% and steerable then the the later one will have 25 % bigger range.

1.Do you know what you are talking about ?

First thing first. now relation between amount of TRM one can Cram into an antenna of phased array with wavelength. When you hit the Limit of the amount of you can put there. It simply said you need a bigger aperture. Not reduction of wavelength/increase in frequency.

Frequency selection on itself are not determined by how many TRM one should put in radar BUT other things like what the radar is supposed to do.

If the aperture are fixed and the module counts hits the limit of what can be put there, but range have to be increased. Designers then have the following options :
1.Reduce noise factor
2.Increase power rating of the module
3.Increase in beam dwell time
4.Increase in emitted pulsewidth
5.Increase in the amount of pulses being emitted (Increased PRF)


2. What steerable radar ? Both N036 and APG-81 are fixed array. NONE of them capable of physically move their aperture. And what are "countless parameters" you are talking here ?

Instead of using weird term as "countless parameters" Why not using Radar Range Equation to show your point ? Let's examine your numbers :

We have 2 apertures, then one is 30% bigger that is a factor of 1.3. So then we can simply use the 4th root as follows :

Rf=((1.3/1)^2)^(1/4)
Rf=1.14

So the 30% increase in aperture yield factor of 1.14 or 14% NOT 6%, not 18%, not 25% or 30%

How do you get your numbers ?

 

[Stealthflanker]

It means that the F-35 radar needs to be 3 times more powerfull than the su-35 radar to provide the same performance in all angle.

It means that a bigger , steerable radar in a bigger, more powerfull airframe, with more fuel reserve for cooling could give same or bigger performance than a more complicated and advanced radar with smaller dimension in a smaller airframe.

Su-57 and 75 which were talked here using N036. Which is a FIXED array. Irbis is N035.

 

[Anlsvrthng]

1.Do you know what you are talking about ?

First thing first. now relation between amount of TRM one can Cram into an antenna of phased array with wavelength. When you hit the Limit of the amount of you can put there. It simply said you need a bigger aperture. Not reduction of wavelength/increase in frequency.

Frequency selection on itself are not determined by how many TRM one should put in radar BUT other things like what the radar is supposed to do.

If the aperture are fixed and the module counts hits the limit of what can be put there, but range have to be increased. Designers then have the following options :
1.Reduce noise factor
2.Increase power rating of the module
3.Increase in beam dwell time
4.Increase in emitted pulsewidth
5.Increase in the amount of pulses being emitted (Increased PRF)

To make narrover beam you need to increase the transmitter count. That means the frequency going up, and the edge scattering/effect of RAM will be more significant.

2. What steerable radar ? Both N036 and APG-81 are fixed array. NONE of them capable of physically move their aperture. And what are "countless parameters" you are talking here ?

Instead of using weird term as "countless parameters" Why not using Radar Range Equation to show your point ? Let's examine your numbers :

We have 2 apertures, then one is 30% bigger that is a factor of 1.3. So then we can simply use the 4th root as follows :

Rf=((1.3/1)^2)^(1/4)
Rf=1.14

So the 30% increase in aperture yield factor of 1.14 or 14% NOT 6%, not 18%, not 25% or 30%

How do you get your numbers ?

30% increase in photon collectiong area, not in diameter.

Again, the point is simple, bigger / heavier means more powerfull, spending more RnD could compensate the disadvantage.

 

[Stealthflanker]

To make narrover beam you need to increase the transmitter count. That means the frequency going up, and the edge scattering/effect of RAM will be more significant.

Are you seriously know what you are talking about ? I am not even talking about Beamwidth here. My point is that there are MANY options other than increasing module counts if one desire increased range.

30% increase in photon collectiong area, not in diameter.

Are you talking about Radar or Infra red device ? Again, use radar range equation.

What i am using in my calculation is GAIN.. which is related to ANTENNA AREA or It's effective area. That is why you see "^2" or Square in my calculations.

If one antenna have 30% bigger AREA than the other the gain would be in factor of 1.69 or 69% But the range is then only a factor of 1.14 or 14%. That is the 4th Root law of Radar propagation.