F-35 vs Su-30/35

The F-35 compared with other modern jets.
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archeman

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Unread post02 Apr 2015, 01:59

bring_it_on wrote:
archeman wrote:
bring_it_on wrote:Thats Canadian estimate of worldwide classified RAM material development.


Posted that to demonstrate that the idea that there is some kind of generic 'Normal RAM Coating' is kind of overly simplistic assumption. Even though that is kind of an old paper and addresses only non-clasified RAM materials and assembly techniques and attenuation methods, the field is very deep indeed.


Of course it is deep, but it is not going to give you a reasonable estimate on what is achieved by a highly classified product developed by and for a user that has had experience with RAM that goes into decades.


Yes, exactly my point.
There is probably many different materials, thicknesses, layers, inductance and capacitance absorption grids, bonding methods and using varying application and repair techniques based on the RF risk and environment of a particular surface.
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Unread post02 Apr 2015, 07:36

sergei wrote:
hornetfinn wrote:
sergei wrote:" AN/APG-81 likely has quite a bit more as it has more and likely newer (higher efficiency and higher power) modules and probably has better cooling capacity. I see it possibly having closer to 10 kW average output power, which is huge amount of power for a fighter radar."

Apg-81 can track target with RCS = 1m2 from 150 km in LPI
:?


I'd really like to know the source for these figures. Could you provide a credible source?


It is necessary to ask eloise

eloise Fri Mar 27, 2015 4:42 pm

After a short search I find it probable:

http://www.youtube.com/watch?v=wIwAOupjMeM
1.31
and
http://www.youtube.com/watch?v=5lPZDc8mzsY
6.02

P/S read all post not only latest.


Thank you for those videos, nice find!

How am I supposed to know that you were referring to eloise's post? Anyway, those numbers seem like someone's estimate from 10-15 years ago. For example F-22 AN/APG-77 figures flying around come from estimates published in Aviation Week and Jane's in 1999 and 2000. That's 15-16 years ago and several years before F-22 even reached IOC. Of course then it AN/APG-77 was supposed to have only 1,500 T/R modules as in reality it has quite a bit higher count (about 2,000) and thus longer range. As those numbers have become the truth to many people, they just calculate what the AN/APG-81 range would be as it has smaller array. Of course there might have been some improvements over original AN/APG-77 during the last 15 years or so...

Btw, your first video does show AN/APG-81 test (starting at about 1:00) where the longest range tracks are well over 80 nautical miles away. Of course we do not know the RCS of the targets, what the test conditions are or how far the longest range targets actually are. Interesting detail is that the radar beams appear to be of different shapes, probably optimizing search and tracking functions in each beam.
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Unread post02 Apr 2015, 09:43

hornetfinn wrote:
sergei wrote:" AN/APG-81 likely has quite a bit more as it has more and likely newer (higher efficiency and higher power) modules and probably has better cooling capacity. I see it possibly having closer to 10 kW average output power, which is huge amount of power for a fighter radar."

Apg-81 can track target with RCS = 1m2 from 150 km in LPI
:?

I'd really like to know the source for these figures. Could you provide a credible source?


It is necessary to ask eloise

eloise Fri Mar 27, 2015 4:42 pm

After a short search I find it probable:

http://www.youtube.com/watch?v=wIwAOupjMeM
1.31
and
http://www.youtube.com/watch?v=5lPZDc8mzsY
6.02

P/S read all post not only latest.

---------------------------------------------------------
Thank you for those videos, nice find!

How am I supposed to know that you were referring to eloise's post? Anyway, those numbers seem like someone's estimate from 10-15 years ago. For example F-22 AN/APG-77 figures flying around come from estimates published in Aviation Week and Jane's in 1999 and 2000. That's 15-16 years ago and several years before F-22 even reached IOC. Of course then it AN/APG-77 was supposed to have only 1,500 T/R modules as in reality it has quite a bit higher count (about 2,000) and thus longer range. As those numbers have become the truth to many people, they just calculate what the AN/APG-81 range would be as it has smaller array. Of course there might have been some improvements over original AN/APG-77 during the last 15 years or so...

Btw, your first video does show AN/APG-81 test (starting at about 1:00) where the longest range tracks are well over 80 nautical miles away. Of course we do not know the RCS of the targets, what the test conditions are or how far the longest range targets actually are. Interesting detail is that the radar beams appear to be of different shapes, probably optimizing search and tracking functions in each beam.[/quote]
---------------------------------------------------------------------
"well over 80 nautical miles " 100nm to be more precise but " we do not know the RCS of the targets"
Instrumental range F35 avionic more than 500 km.
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Unread post02 Apr 2015, 13:01

sergei wrote:"well over 80 nautical miles " 100nm to be more precise but " we do not know the RCS of the targets"
Instrumental range F35 avionic more than 500 km.


Actually we do not know exactly how the display system works and how far away the targets really are when they are further away than that 80 nm range circle. It might be about that 100 nm or it might just show that the target is more distant than that 80 nm. Of course such videos likely will not show any really interesting things about performance, but even if it was 100 nm, then the tracking ranges are quite impressive (regardless of RCS) given that it's searching that whole field of view while tracking large number of targets. Narrowing that down to some small area would considerably increase range performance. Besides, this video does not try to present anything about performance envelope and I don't think we can draw that many conclusions about videos like it.
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Unread post04 Apr 2015, 12:27

Think I posted it on this forum once before, but there's a moment in that segment of video where the radar is simultaneously tracking 6 separate targets, then detects a new target beyond 80 nm at the same time.

Assuming the power is being distributed equally across all 7 beams, and taking into account the low gain due to the heavily thinned array, it implies that the maximum detection range for those particular targets is in the 200 nm+ range. Potentially gives the APG-81 similar range to the Irbis-E unjammed and far better range in jamming conditions.
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Unread post06 Apr 2015, 09:37

munny wrote:Think I posted it on this forum once before, but there's a moment in that segment of video where the radar is simultaneously tracking 6 separate targets, then detects a new target beyond 80 nm at the same time.

Assuming the power is being distributed equally across all 7 beams, and taking into account the low gain due to the heavily thinned array, it implies that the maximum detection range for those particular targets is in the 200 km+ range. Potentially gives the APG-81 similar range to the Irbis-E unjammed and far better range in jamming conditions.


Small correction for greater realism.

P/S " power is being distributed" I'm certainly not a great expert on the radio location but it is news to me.
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Unread post06 Apr 2015, 13:49

Nope, no mistake there.

Assuming the radar is using 1/7th of its power and aperture area to detect that new target at 80nm, we can approximate the maximum range to detect the target with a single beam using all TRMs by using the range equation. Basically the forth root of 7 times the power * 7 times the gain squared, or basically single beam range = 80nm * 7^3^.25

Comes to about 4 times greater range if it uses a single beam on all TRMs. So based on an 80nm (140ish km) detection of the targets with a 1/7th thinned array, it could theoretically have a maximum detection range for the targets tested of around 620km before factoring in atmospheric attenuation.

Shouldn't be a great surprise that the 81 can vastly outperform the irbis. Consider 1650+ modules running at a peak of 15w each with a higher gain and better duty cycle due to cooling. It's only a matter of time until GaN is used (30w and 60w modules seem to be the sweet spot for manufacturers right now). Their current products have an excellent frequency range to, 6-12GHz for amplifiers suitable for fighter radar. DoD may just skip straight to Diamond substrates though which have had massive advances in the past year and yield 3 times the power and double the life of GaN TRMs.

No mistakes about it, US semiconductor research and manufacturing is in a different league to what the Russians are doing right now. All major US transistor makers are using GAN exclusively right now and TEGaN (diamond wafers) has been developed and is about to boom. Russia are still prototyping GaN on SiC and have no means of mass manufacturing due to their reliance on European equipment and sanctions on dual purpose equipment.
Last edited by munny on 06 Apr 2015, 14:28, edited 2 times in total.
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Unread post06 Apr 2015, 14:15

Sounds like F-14D scan range only using four F-14D's lined abreast at 30 km increments. :)
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Unread post06 Apr 2015, 21:05

munny wrote:Nope, no mistake there.

Assuming the radar is using 1/7th of its power and aperture area

Why do you think the radar will operate in such a strange mode?
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Unread post06 Apr 2015, 23:07

sergei, this is not a "strange mode". This is what makes AESA different than PESA. Different groups of T/R modules are doing different things in different areas of the sky in different frequencies at the same time.
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Unread post06 Apr 2015, 23:23

That was a strange question.
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Unread post07 Apr 2015, 09:37

sprstdlyscottsmn wrote:sergei, this is not a "strange mode". This is what makes AESA different than PESA. Different groups of T/R modules are doing different things in different areas of the sky in different frequencies at the same time.


Exactly. PESA and MSA radars can create only one beam of relatively constant power and that one beam is all they can work with. AESA can theoretically create as many beams as they have T/R modules (very impractical in reality), but in practice they can usually create a handful of beams (like 3-8 for fighter radars). If only one (transmit) beam is used, then all the T/R modules work together to create that beam. Then all the available power goes to generating that one beam. End result is one very powerful beam which can be used to look very far. However using only one beam will result in reduced search area or increased scan time (takes a lot longer to scan the volume) depending on which is more important. Using all the power all the time is also not good for LPI and EW considerations.

Much of the radar tasks can be achieved with much less power than max power. For example tracking nearby large RCS target requires very little power. Looking up or down more than 10 degrees will also require very little power most of the time as targets will be rather close (less than 60 km away from normal operating altitudes). So AESA radar can scan some parts of the whole search area with very strong beams and some areas with weaker beams. Same with tracking different targets. A B-52 or Tu-95 30 km away will require very very weak beam to track. Stealthy target 100 km away will require a lot of power for constant tracking. Given that modern AESA radars have a large number of powerful T/R modules, they can generate several beams simultaneously and each beam can have as much average power as most MSA or PESA radars can generate in their only beam. Basically AESA will use only as much power as is required to achieve each task. Using multiple simultaneous beams they can scan far larger area of the sky than MSA or PESA radar could or they can do so to much longer distances or shorter scan times. For example Russian PESA radars from Zaslon-A to Irbis-E have scan areas of about 100 to 300 square degree area (like about 10x10 to 30x10 degree box) depending on modes according to Russian sources. AESA radars can scan far larger area of the sky (several thousand square degrees) and still have good range and target tracking performance.

People seem to think that Irbis-E is some ultimate radar that has as good performance as can be had. This is very far from truth (although Irbis-E seems to have very respectable performance) and similar or superior performance can definitely be had from smaller AESA radars. The performance will grow in the future and there doesn't seem to be end to this development.
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Unread post07 Apr 2015, 13:46

hornetfinn wrote:
sprstdlyscottsmn wrote:sergei, this is not a "strange mode". This is what makes AESA different than PESA. Different groups of T/R modules are doing different things in different areas of the sky in different frequencies at the same time.

Exactly. PESA and MSA radars can create only one beam of relatively constant power and that one beam is all they can work with. AESA can theoretically create as many beams as they have T/R modules (very impractical in reality), but in practice they can usually create a handful of beams (like 3-8 for fighter radars). If only one (transmit) beam is used, then all the T/R modules work together to create that beam. Then all the available power goes to generating that one beam. End result is one very powerful beam which can be used to look very far. However using only one beam will result in reduced search area or increased scan time (takes a lot longer to scan the volume) depending on which is more important. Using all the power all the time is also not good for LPI and EW considerations.

Much of the radar tasks can be achieved with much less power than max power. For example tracking nearby large RCS target requires very little power. Looking up or down more than 10 degrees will also require very little power most of the time as targets will be rather close (less than 60 km away from normal operating altitudes). So AESA radar can scan some parts of the whole search area with very strong beams and some areas with weaker beams. Same with tracking different targets. A B-52 or Tu-95 30 km away will require very very weak beam to track. Stealthy target 100 km away will require a lot of power for constant tracking. Given that modern AESA radars have a large number of powerful T/R modules, they can generate several beams simultaneously and each beam can have as much average power as most MSA or PESA radars can generate in their only beam. Basically AESA will use only as much power as is required to achieve each task. Using multiple simultaneous beams they can scan far larger area of the sky than MSA or PESA radar could or they can do so to much longer distances or shorter scan times. For example Russian PESA radars from Zaslon-A to Irbis-E have scan areas of about 100 to 300 square degree area (like about 10x10 to 30x10 degree box) depending on modes according to Russian sources. AESA radars can scan far larger area of the sky (several thousand square degrees) and still have good range and target tracking performance.

People seem to think that Irbis-E is some ultimate radar that has as good performance as can be had. This is very far from truth (although Irbis-E seems to have very respectable performance) and similar or superior performance can definitely be had from smaller AESA radars. The performance will grow in the future and there doesn't seem to be end to this development.

The problem is that before turn on the radar you do not know what is near, is it large RCS target like bomber? or it may be small fighter very far away? To track large RCS target do not need many power it is true, but to that would be confident in discovering new targets at maximum range you must use the maximum power.
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Unread post07 Apr 2015, 16:06

@hornetfinn,
can you talk to the reliability of AESA vs legacy radars? How robust are T/R modules and what kind of MTBFs can we expect with new GaN tech?
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Unread post07 Apr 2015, 17:51

sergei wrote:
hornetfinn wrote:
sprstdlyscottsmn wrote:sergei, this is not a "strange mode". This is what makes AESA different than PESA. Different groups of T/R modules are doing different things in different areas of the sky in different frequencies at the same time.

Exactly. PESA and MSA radars can create only one beam of relatively constant power and that one beam is all they can work with. AESA can theoretically create as many beams as they have T/R modules (very impractical in reality), but in practice they can usually create a handful of beams (like 3-8 for fighter radars). If only one (transmit) beam is used, then all the T/R modules work together to create that beam. Then all the available power goes to generating that one beam. End result is one very powerful beam which can be used to look very far. However using only one beam will result in reduced search area or increased scan time (takes a lot longer to scan the volume) depending on which is more important. Using all the power all the time is also not good for LPI and EW considerations.

Much of the radar tasks can be achieved with much less power than max power. For example tracking nearby large RCS target requires very little power. Looking up or down more than 10 degrees will also require very little power most of the time as targets will be rather close (less than 60 km away from normal operating altitudes). So AESA radar can scan some parts of the whole search area with very strong beams and some areas with weaker beams. Same with tracking different targets. A B-52 or Tu-95 30 km away will require very very weak beam to track. Stealthy target 100 km away will require a lot of power for constant tracking. Given that modern AESA radars have a large number of powerful T/R modules, they can generate several beams simultaneously and each beam can have as much average power as most MSA or PESA radars can generate in their only beam. Basically AESA will use only as much power as is required to achieve each task. Using multiple simultaneous beams they can scan far larger area of the sky than MSA or PESA radar could or they can do so to much longer distances or shorter scan times. For example Russian PESA radars from Zaslon-A to Irbis-E have scan areas of about 100 to 300 square degree area (like about 10x10 to 30x10 degree box) depending on modes according to Russian sources. AESA radars can scan far larger area of the sky (several thousand square degrees) and still have good range and target tracking performance.

People seem to think that Irbis-E is some ultimate radar that has as good performance as can be had. This is very far from truth (although Irbis-E seems to have very respectable performance) and similar or superior performance can definitely be had from smaller AESA radars. The performance will grow in the future and there doesn't seem to be end to this development.

The problem is that before turn on the radar you do not know what is near, is it large RCS target like bomber? or it may be small fighter very far away? To track large RCS target do not need many power it is true, but to that would be confident in discovering new targets at maximum range you must use the maximum power.



Sergei, if I can give you a complement. Its astounding how confidently you speak, with such little knowledge.
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