Can the F-35 match the PAK-FA

The F-35 compared with other modern jets.
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haavarla

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Unread post07 Jan 2013, 16:23

More power will give 18% advantage in range??
How on earth did you calculate this?
Do you know how which areal the PF Array will have, do you know how many transmitters it will have and do you know how much power it will have?

Pls do share.

I do not put up any figures cause its doomed to be wrong, but on this forum there are litterly 5 top engineers working for Sukhoi whom can shedd some light on everything regarding PF. Amazing!!

The AN/APG-63(V)2 and (V)3 is not exactly cutting edge radar development, but merly an upgrade in which they use back end from another radar.
One question, how big is the AN/APG-63(V)2 array?
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Unread post07 Jan 2013, 18:43

haavarla wrote:
The AN/APG-63(V)2 and (V)3 is not exactly cutting edge radar development, but merly an upgrade in which they use back end from another radar.
One question, how big is the AN/APG-63(V)2 array?


The (v)2 isn't the latest technology, but please list one adversary flying with a more capable radar. The (v)3 is even more capable, and the -82 more capable still.
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thegroundeffect

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Unread post07 Jan 2013, 20:31

neurotech wrote:Lets just skip over the semantics of Su-35 is operational status. The point is that the F-22/APG-77 & F/A-18/APG-79 combo has been operational for a long longer than the maybe less than 12 months the Su-35 has been in operational evaluation. Russia doesn't have a mature AESA design.

Since I'm trying to be fair and balanced, I'm going to release a little "secret" piece of information here. The semiconductor GaAS MMICs used in AESA radar are available as "dual use" technology as they are used in Mobile telecom and microwave relay stations. In some cases, they are even made in China. What the Chinese/Russian are working on is the R&D on how to combine 100s or 1000s of these things in an array, and keep it cool and reliable, including RF stability. They also probably don't have the same level of signal processors and the code to drive them.


Neurotech, how does this Russian/Chinease aproch differ from the western AESA radars?

Not trying to sollicitate for secrets, i'm just curious about why they would chose this design if there are other options, like you are implaying.
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neurotech

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Unread post07 Jan 2013, 21:12

thegroundeffect wrote:
neurotech wrote:Lets just skip over the semantics of Su-35 is operational status. The point is that the F-22/APG-77 & F/A-18/APG-79 combo has been operational for a long longer than the maybe less than 12 months the Su-35 has been in operational evaluation. Russia doesn't have a mature AESA design.

Since I'm trying to be fair and balanced, I'm going to release a little "secret" piece of information here. The semiconductor GaAS MMICs used in AESA radar are available as "dual use" technology as they are used in Mobile telecom and microwave relay stations. In some cases, they are even made in China. What the Chinese/Russian are working on is the R&D on how to combine 100s or 1000s of these things in an array, and keep it cool and reliable, including RF stability. They also probably don't have the same level of signal processors and the code to drive them.


Neurotech, how does this Russian/Chinease aproch differ from the western AESA radars?

Not trying to sollicitate for secrets, i'm just curious about why they would chose this design if there are other options, like you are implaying.

The signal processing system in a AESA isn't much different than a PESA radar. Where the big change occurs is the how the radar is driven. AESA uses multiple smaller transmitters instead of one big power amp driving the array.

As for specifics on the Russian/Chinese approach.. I'm not sure there are major differences in "approach". I don't know much about the Russian radars except that they seem to be larger and heavier than the US ones, for the range/performance. The Russians/Chinese try and minimize technical risk, whereas the top US radars such as the APG-81 are more integrated to mission systems than previous versions. Older radars, like the APG-79 are practically a drop-in replacement for the APG-73 without major changes to avionics architecture.
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thegroundeffect

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Unread post07 Jan 2013, 21:38

neurotech wrote:
thegroundeffect wrote:
neurotech wrote:Lets just skip over the semantics of Su-35 is operational status. The point is that the F-22/APG-77 & F/A-18/APG-79 combo has been operational for a long longer than the maybe less than 12 months the Su-35 has been in operational evaluation. Russia doesn't have a mature AESA design.

Since I'm trying to be fair and balanced, I'm going to release a little "secret" piece of information here. The semiconductor GaAS MMICs used in AESA radar are available as "dual use" technology as they are used in Mobile telecom and microwave relay stations. In some cases, they are even made in China. What the Chinese/Russian are working on is the R&D on how to combine 100s or 1000s of these things in an array, and keep it cool and reliable, including RF stability. They also probably don't have the same level of signal processors and the code to drive them.


Neurotech, how does this Russian/Chinease aproch differ from the western AESA radars?

Not trying to sollicitate for secrets, i'm just curious about why they would chose this design if there are other options, like you are implaying.

The signal processing system in a AESA isn't much different than a PESA radar. Where the big change occurs is the how the radar is driven. AESA uses multiple smaller transmitters instead of one big power amp driving the array.

As for specifics on the Russian/Chinese approach.. I'm not sure there are major differences in "approach". I don't know much about the Russian radars except that they seem to be larger and heavier than the US ones, for the range/performance. The Russians/Chinese try and minimize technical risk, whereas the top US radars such as the APG-81 are more integrated to mission systems than previous versions. Older radars, like the APG-79 are practically a drop-in replacement for the APG-73 without major changes to avionics architecture.


Oke, so if I understand correctly, the Russians/Chinese are basicaly trying to do the same as the US. The difference is that they haven't reached the same level op technology yet.

Thanks for your quick aswer!


Cheers.
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neurotech

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Unread post07 Jan 2013, 21:50

thegroundeffect wrote:
neurotech wrote:As for specifics on the Russian/Chinese approach.. I'm not sure there are major differences in "approach". I don't know much about the Russian radars except that they seem to be larger and heavier than the US ones, for the range/performance. The Russians/Chinese try and minimize technical risk, whereas the top US radars such as the APG-81 are more integrated to mission systems than previous versions. Older radars, like the APG-79 are practically a drop-in replacement for the APG-73 without major changes to avionics architecture.


Oke, so if I understand correctly, the Russians/Chinese are basicaly trying to do the same as the US. The difference is that they haven't reached the same level op technology yet.

Pretty much, that is the impression I'm under. What I was suggesting about the MMIC details was that there isn't some huge technical brickwall to the Russians/Chinese developing AESA radar, but it takes time and R&D expenditure.
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Unread post07 Jan 2013, 23:31

haavarla wrote:More power will give 18% advantage in range??
How on earth did you calculate this?
Do you know how which areal the PF Array will have, do you know how many transmitters it will have and do you know how much power it will have?



It's really not possible to make a fixed estimate like this as signal loss is a function of many inputs in addition to distance and power. But I think the basic point is that doubling power will not mean doubled range, and my wild guess is that 18mi may be a best case scenario that somebody did with assumption of common values on the rest of the eqautions.

The formula(s) to guess signal loss are usually expressed in dBm which is an exponential measure and signal loss is combination of signal propagating in the shape of a sphere (1/distance^2) and the effects of attenuation by things like scattering of signal through a medium (air, water vapor, etc.) and wavelength effects on an antenna. In the case of radar the distance variable in the formula must be multiplied by 2 for the return trip and formula for reflection off the object given different wavelengths.

Given these multiple signal loss factors, I can easily see where doubling power only nets a gains of 10% or less of additional distance, however this no doubt will vary widely from factors like humidity, antenna/return angles, etc.
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Unread post07 Jan 2013, 23:33

alloycowboy wrote:
haavarla wrote:Plain wrong!
The F-35 is fat, short and bumpy due to one reason alone.
Its the hand it was dealt when the designers got the Requirements from both USAF, USN and USM. It had to be able to fit on the ramp in CV.

So for some reason lost to me, they decided that the F-35A for USAF was to share all the traits, shape and size(more or less) that the B and C version.
I think the idea was that this would save huge buckets of funding.. go figure ;)



Generally when you design an airplane the first thing you do is spec the engine. Second thing you need to decide is how far you need it to go and at what speed as this determines your fuel load. The third thing you need to decide is what weapons it is going to carry. So Engine size and weight+
fuel weight+weapons weight will pretty much determine the size and weight of the aircraft and it will determine how much wing area you need. Once you have the wing area figured out you can size the horizontal stablizers and vertical stabalizer. In the old days they would just stretch out the nose of the aircraft to get more fuel and range but now with advanced CFD they use a high volume low drag airframe design. (F-86 to F-16 to F-35)


High volume and low drag, subsonically, right?
I hope any of you can elaborate on this low drag topic.
I can see similar proportion on high volume design of A-6 intruder. But for supersonic focused aircraft designs, like F-22, I still see stretching out longitudinally, rather than stretching cross-section.
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Unread post08 Jan 2013, 02:10

haavarla wrote:More power will give 18% advantage in range??
How on earth did you calculate this?
Do you know how which areal the PF Array will have, do you know how many transmitters it will have and do you know how much power it will have?


rough % advantage = ((power of stronger radar / power of weaker radar) ^ (1/4)-1)*100

I'm sure you've been made aware of the fact that a radar requires 16 times more power just to double it's range from power alone. This comes about because the 4th root of all radar parameters and target RCS are used in the max range equation (power, transmit gain, receive gain, MDS...etc).
The square root of wavelength is used (much of the reason why it impacts a lot on detection range)

So, if you have a radar with all other parameters being equal, but it has double the power, the actual advantage is less than the 4th root of 2. The reason it is less is due to increased losses arising from greater base range, higher internal temperature, atmospheric conditions...and a whole lot more.

All this is why attention to detail with stealth is a better path to follow than advancements in radar. Its damn difficult doubling your radar power, but relatively much more easy to halve your RCS to gain an advantage over a threat. Eg. The PAK FA may have double the radar power and larger aperture than an F-35, but if the F-35 has 1/10th the frontal RCS (and some public comments suggest it may actually be more like 1/200th in x-band), it will still have the detection range advantage.

The US has done the right thing in their no compromise approach to frontal aspect stealth (and much less compromised approach to side stealth than the PAK FA) with a moderately sized/powered aperture (aperture size and angle affects RCS too).

You really have to appreciate the way US designers are exploiting radar equations to get maximum advantage for money.

- They tackled RCS first because RCS reduction provides very good effectiveness for money/time to mature technologies.
- With GaN on Diamond coming soon they simultaneously improve power + minimum discernible signal all at once (as opposed to just boosting power alone)

What's next? I say high gain L-band mounted on very large, stealthy airframes.
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Unread post08 Jan 2013, 06:04

neurotech wrote:
haavarla wrote:Only that the first thing the designers had to do was to calculate and add on all the necessary Carrier operation feats. As we all know is that this add a fair share of Cons in the way different performance spell out on. see F-14 and SH among other..
So when you first set about designing the jet the first thing is these CV operation constraints. The physical size and shape of the F-35 very much goes to show my point.
From there you can try and do your best shot, but still in the limitation of those requirements you have been given.

Compare the YF-17 for the USAF, with the F/A-18A for the Navy. The F/A-18 not that much different overall.

The shape of the F-35 is dictated by the large single engine, and the need for good subsonic/transonic performance, as opposed to jets like the F-104 which has supersonic optimized intakes. Remember the F-16 "big mouth" upgrade for the Block 30. The original intake wasn't optimized for higher thrust engines. The F-35 intake design gives the engines superb thrust from subsonic to transonic to supersonic.


In regards to transonic performance, I remember F-35 is described as: "acceleration from Mach 0.8 to Mach 1.2 at 30,000 ft. in 61 sec", not an impressive number, comparing to F-16 / F-18 acceleration from 0.8 to 1.2 with 2 IR 2 AMRAAM.
Although F-35 is also described as aerodynamical performance comparable to F-16 / F-18 clean, thus supposed to be better than F-16 / F-18 with load.
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Unread post08 Jan 2013, 06:29

'megasun': here is the reference for your remembered claim? "..In regards to transonic performance, I remember F-35 is described as: "acceleration from Mach 0.8 to Mach 1.2 at 30,000 ft. in 61 sec",...".

F-35 Air Combat Skills Analyzed Aviation Week's DTI | Andy Nativi | March 06, 2009 This article first appeared in Aviation Week & Space Technology

http://www.military.com/features/0,15240,186349,00.html

Which article ends with this disclaimer: "...It is not clear how critical such perceived shortcomings truly are. Some pilots argue that in a dogfight, the air-to-air missile has more to do with the engagement's outcome than does the aircraft."
_______________

A forum discussion here c.July 2010: BF-02 Supersonic

http://www.f-16.net/f-16_forum_viewtopi ... rt-60.html
Last edited by spazsinbad on 08 Jan 2013, 06:35, edited 2 times in total.
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haavarla

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Unread post08 Jan 2013, 06:31

wrightwing wrote:
haavarla wrote:
The AN/APG-63(V)2 and (V)3 is not exactly cutting edge radar development, but merly an upgrade in which they use back end from another radar.
One question, how big is the AN/APG-63(V)2 array?


The (v)2 isn't the latest technology, but please list one adversary flying with a more capable radar. The (v)3 is even more capable, and the -82 more capable still.


Compaired to the (V)2?
The obvious first then, Zalson-M, Second most likely an upgraded BARS being fittet on Su-30SM. And the Irbis-E radar.

Its pretty certain the AESA on the PF will out perform the (V)2 radar.
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Unread post08 Jan 2013, 09:02

haavarla wrote:Its pretty certain the AESA on the PF will out perform the (V)2 radar.

How do you figure that? And be "pretty certain" about it? We don't have performance data on the Irbis-E radar to objectively compare the performance to that of a the APG-63(V)2. One of the key requirements of a 4.5th Gen fighter radar is to resist jamming. Another factor is how well it filters background clutter and noise. A 4.5th Gen fighter radar shouldn't be measuring range at 1m2 RCS, as the the real question would be what its range at 0.1m2 RCS, any ideas? Considering the F-35 EODAS can detect a fighter at over 40 miles, I doubt the Irbis-E can detect a F-35 at that range.

More importantly, its kind of a moot point as the USAF is getting APG-82s into the F-15s before the PAK-FA or even Su-35(Irbis-E) is available for operational combat deployment - if you consider state "operational testing" as operational.
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Unread post08 Jan 2013, 10:46

megasun wrote:
neurotech wrote:
haavarla wrote:Only that the first thing the designers had to do was to calculate and add on all the necessary Carrier operation feats. As we all know is that this add a fair share of Cons in the way different performance spell out on. see F-14 and SH among other..
So when you first set about designing the jet the first thing is these CV operation constraints. The physical size and shape of the F-35 very much goes to show my point.
From there you can try and do your best shot, but still in the limitation of those requirements you have been given.

Compare the YF-17 for the USAF, with the F/A-18A for the Navy. The F/A-18 not that much different overall.

The shape of the F-35 is dictated by the large single engine, and the need for good subsonic/transonic performance, as opposed to jets like the F-104 which has supersonic optimized intakes. Remember the F-16 "big mouth" upgrade for the Block 30. The original intake wasn't optimized for higher thrust engines. The F-35 intake design gives the engines superb thrust from subsonic to transonic to supersonic.


In regards to transonic performance, I remember F-35 is described as: "acceleration from Mach 0.8 to Mach 1.2 at 30,000 ft. in 61 sec", not an impressive number, comparing to F-16 / F-18 acceleration from 0.8 to 1.2 with 2 IR 2 AMRAAM.
Although F-35 is also described as aerodynamical performance comparable to F-16 / F-18 clean, thus supposed to be better than F-16 / F-18 with load.


I can't speak one way or another about this, but I do know with its massive thrust and high fuel fraction that is a turning engagement the -35 WILL not spiral down down the telephone pole of bleeding away energy and altitude to the same extent as a legacy fighter. This certainly is much more important than winning a drag race. After all, I do know not a single aircraft flying today can accellerate from M.8 to any speed at all which will put it out of range of ANY AAM when trying to end a turning engagement and bug out to safety - PF included. Better than accellerating by a whole whopping .4M is having LO to NOT be rageted by an AAM. And remember the -35 will numerical sueriority of at least 5x which means the PF will be overhwhelmed by a salvo of -35s with a large salvo of AAMs. I'm certainly not losing any sleep because a single -35 might or would lose a drag race to a single PF.
(and how fast is a -35 from M.8 to M1.2? Is it 5s slower? 7s slower? In other words irrelevent in a real combat situation)
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Unread post08 Jan 2013, 14:38

neurotech wrote:
haavarla wrote:Its pretty certain the AESA on the PF will out perform the (V)2 radar.

How do you figure that? And be "pretty certain" about it? We don't have performance data on the Irbis-E radar to objectively compare the performance to that of a the APG-63(V)2. One of the key requirements of a 4.5th Gen fighter radar is to resist jamming. Another factor is how well it filters background clutter and noise. A 4.5th Gen fighter radar shouldn't be measuring range at 1m2 RCS, as the the real question would be what its range at 0.1m2 RCS, any ideas? Considering the F-35 EODAS can detect a fighter at over 40 miles, I doubt the Irbis-E can detect a F-35 at that range.

More importantly, its kind of a moot point as the USAF is getting APG-82s into the F-15s before the PAK-FA or even Su-35(Irbis-E) is available for operational combat deployment - if you consider state "operational testing" as operational.


My guess is as good as yours, About Radars performance. But AESA is not immune against Jammers and noise enviroment.

About the APG-82s. That would be the F-15E.

Lets not get ahead of our self now..

"The APG-82 is currently in the System Development and Demonstration phase, though low-rate production has begun. Flight tests began in 2010, and Boeing expects to achieve Initial Operational Capability during FY 2014."

http://raytheon.mediaroom.com/index.php?s=43&item=2170

"Raytheon is scheduled to begin delivery of the LRIP-2 radar systems in February 2014. Final delivery of the initial LRIP lot of six APG-82(V)1 radars is scheduled to be completed by that date"

Pls stop these wild claims about ANG-82 being operational before the Irbis-E.
Pls do some research before posting.

"Irbis-E development started in 2004 and the first radar prototype entered flight tests on board an Su-30M2 aircraft acting as a test bed in early 2007. The resulting radar system provides air-to-air, air-to-sea and air-to-ground (ground mapping, Doppler beam sharpening and Synthetic Aperture Radar modes) modes with improved performance in intense clutter environments compared to its predecessor, the Bars system. In addition, Irbis has been designed to detect low and super-low observable/stealth airborne threats"

The Irbis-E is operational, the APG-82 is not.
Last edited by haavarla on 08 Jan 2013, 19:52, edited 3 times in total.
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