JF-17B Updates, News & Discussion

[krash]

Radomes ....

why overhaul JF-17 radomes are in this colour ....

I like them. Primarily, because they look better. Secondarily, because the USAF, during DACT exercises in the earlier years of the F-16, found out that the darker colored radomes made you a fair bit easier to spot.

Aoa sir, I have failed to convey, sir if there are 50 JF 17 using air cooled AESA radar with package from east and 50 JF using liquid cooled AESA radar with package from west can be used as a pair and will able to deliver two kind of integrated weapons for just an example I.e SD 10 as well AMRAAM, then what is obstacle ? Two different Radar with two different package integrated???

The problem would be the logistics of it all. 1) The more you produce/procure of an item the less costly it becomes due to economies of scale. So by dividing the quantities between two different 'radar + package' you'd be increasing the costs of both options. Costs which could be saved and then spent on buying more of the same or of another item. 2) It would take twice as much effort, time, money, and expertise to integrate, validate, and then maintain two separate systems at the same time. 3) If the radars are not a 1 for 1 match, there would have to be two different sub assemblies for manufacturing the airframes. Two different regimens for the training of pilots, engineers, and support staff. Two different sets of operational procedures. Etc. etc. If the radars + packages are a 1 for 1 match then the whole issue is moot.

To minimize all of the above, you opt for commonality as much as you can. In an ideal world an Air Force would have a single type of aircraft that can do anything and everything at peak performance.

 

[TsAr]

Does this air-cooled and liquid-cooled dichotomy have something to do with the rate of heat transfer through conduction convection? I am just guessing here (not my field) that liquid-cooled systems are able to take away more heat per unit time than air-cooled systems. Is that so?

not talking specifically about radars but yes liquid cooling dissipate more heat as compared to air-cooled systems.

 

[ARMalik]

You should refrain from speculating on highly specialized and technical topics because it is a non-scientific approach. And since you are not a researcher who actively creates new AESA radars, where did you get that 80% number from?

The word 'air cooled' is not very well defined in itself. For example, Leonardo calls its 'osprey' range of radars as air cooled, but they are used as surveillance radars. As far as I know, there is currently no concept of an 'air cooled' radar for fighter jets. I can think of only one explanation for the Chinese claims of air cooled radar for JF-17: a SIC substrate layer for efficient thermal dissipation.

Given the same total input power, i.e., the power that is used to generate radar waves + the power that is needed for cooling, and the same semi-conductor material for the TRMs, an air cooled AESA radar will perform better in terms of power conversion than a liquid cooled AESA radar IF boundary layer defects between the substrate and semi-conducting layer do not play a role. There is a fundamental underlying assumption here: the air cooled AESA uses materials having more efficient thermal conductivity, which is the case for SiC substrate. This superiority of air cooled AESA will be true up till the point where the substrate layer can no longer efficiently dissipate heat. If you go beyond this limit, the air cooled radar cannot keep up, and you enter the realm of liquid cooled AESA radars.

But in the previous paragraph, I used the word 'total input power'. The entire paragraph is written from the perspective of total input power. It is easy to overlook the assumption that both the air-cooled and liquid cooled version have exactly the same semi-conductor material in the TRMs. The total output power per TRM is determined by the bandgap of the semi-conductor, and so you won't see any difference in terms of output power. Which makes your 80% number completely ridiculous and shows you have no understanding of the topic on which you are opinionating.

A final subtlety is that in paragrpah 3 I am talking about going beyond the thermal capability of the substrate, and in paragraph 4 I am saying that the bandgap determines total output power. The TRMs are based on transistors working as power amplifiers and the manufacturing process limits the amount of power amplification you can get. So, if you keep improving your manufacturing, in theory you could go beyond the ability of the substrate. Another way is to increase the total input power, which again is limited by the manufacturing process. This is currently an area of active research and nothing can be said with surety, until the Chinese publish their research.

Seriously dude, get your head out of your arse. You are a freak show. There is a reason why all air cooled equipment has limitation. Become an engineer first or at least improve you skills and then come and talk to me. Here is hint for you - start of with learning basic CHT . See ya.

 

[CriticalThought]

Does this air-cooled and liquid-cooled dichotomy have something to do with the rate of heat transfer through conduction convection? I am just guessing here (not my field) that liquid-cooled systems are able to take away more heat per unit time than air-cooled systems. Is that so?

It is not a dichotomy. There is no AESA radar out there that is cooled solely by air. Even the APG-83 has an inbuilt liquid heat exchanger for immediate removal of heat from the TRMs, and then this heat is further dissipated through air cooling. And all of the current technology has been created for GaAs based TRMs.

Based on the published research from Chinese scientists, I am making the assumption that the Block 3 radar is based on the newer GaN technology that uses SiC as the substrate layer. The SiC layer acts as the heat sink, thus removing the need for liquid cooling of the TRMs, and removing the need for bringing coolant into the radome. The bulk of the radar will be situated in the area under the cockpit and behind the nose cone. Luckily, there is already provisioning for cooling the cockpit!!! Now take a look at where the liquid cooling system of F-18 is situated:

LCDR Nate "Hyber" Marler Advanced Weapons Lab, VX-31 China Lake, Ca | PDF | Military Technology | Electronics

Includes cooling demand and probably cooling capacity for F/A-18E Radar.

www.scribd.com

And finally consider the fact that the base of Block-3 tail has an additional inlet for airflow. These are all the pieces of the puzzle that I currently have. People on this forum are not up to date with latest advancements in AESA technology and are getting confused based on what they know about existing GaAs based AESA radars.

 

[CriticalThought]

f16 AESA update radar doesnt has liquid cooling

The Block 60s for UAE have liquid cooling:

FLIGHT TEST: Lockheed Martin F-16E/F Block 60 - Bridging the gap

www.flightglobal.com

I have found two different versions for APG-83. This source seems to imply purely air cooled solution:

https://www.matec-conferences.org/articles/matecconf/pdf/2019/53/matecconf_easn2019_04001.pdf

2.3 Case study for the F-16: upgrading the MSA radar with an AESA radar Currently, the latest MSA radar on the F-16 is the Northrop Grumman AN/APG-68(V)9. According to open sources, the radar range against a standard target of 1 m² RCS is assumed to be approximately 38 nautical miles (n.m.). The required input power is 5.6 kVA, as was stated in relevant brochures, as well as other sources [12]. The aircraft provides cooling to the radar by air flow, which has been reported to be relatively marginal with respect to the requirements of this radar [12]. The cooling capacity of the aircraft for the radar is expected to be less than 5.6 kW. For the sake of discussion, one can assume 5.5 kW. Following the APG-77 (F-22), the APG-80 (F-16E/F Block 60), as well as the APG-81 (F-35), Northrop Grumman developed the Scalable Agile Beam Radar or SABR in the mid2000s, as a possible upgrade option for the existing F-16 fleet, designed to be installed without making any major modifications to the aircraft. Later, it was designated as AN/APG-83. According to the manufacturer, it integrates within the F-16’s current structural, power and cooling constraints without Group A aircraft modification. It can be assumed that the APG-83 has the same number of TRMs as the APG-80, i.e., 1020 TRMs. Considering GaAs TRMs of 10W each, the peak power is of the 10 kW class. Liquid cooling is used inside the radar, in order to remove the waste heat from the antenna array and the other radar parts, transferring the heat to the aircraft’s air cooling system. Apart from the antenna array, the radar comprises other LRUs (Line Replaceable Units), such as the Receiver Exciter Processor (REP) and the radar rack assembly, including the elements of the internal cooling system. Assuming that these two LRUs produce roughly 1 kW and 0.5 kW of heat, respectively, the upper limit on the antenna array waste heat is approximately 4 kW, in order not to exceed 5.5 kW in total. Considering the available GaAs TRM technology available at the time the SABR was being developed, it can be assumed that the PAE is in the order of 35% and the overall T/R module efficiency is estimated at 20%. Therefore, the average transmitted power can be up to 1 kW, in order not to exceed 4 kW of waste heat, and the duty cycle cannot exceed 10%. This limitation has dire consequences on the detection range, since the average transmitted power is a crucial factor. In this way, the F-16E/F Block 60 was designed taking into account the cooling requirements of the APG-80, providing liquid cooling to the radar and allowing for better performance. Actually, most aircraft featuring an AESA radar provide liquid cooling.

Whereas:

AESA Radar and Technology Developments | AIN

The technology features prominently in fighter competitions.

www.ainonline.com

Developed more than a decade ago, the APG-83 was originally known as the Scalable Agile Beam Radar (SABR) and was intended as part of the upgrade package for older F-16 models. Singapore, South Korea, and the Republic of China are the first three nations that are slated to have this radar set installed to replace different models of the older, mechanically steered NG AN/APG-68 radar set.

Specialists at other radar design houses question how effective the APG-83 can be since the set depends on using the airflow that cools the other avionics in the F-16 and then using an internal liquid-cooling module and heat exchanger that is on-board the radar set itself.

“This has the advantage of not having to plumb a liquid-cooling system into the aircraft, as Lockheed Martin did with the F-16E/F Block 60 for the UAE,” said a U.S. airborne radar firm’s representative. “But the question is whether or not that cooling solution allows you to run the radar’s T/R modules at their maximum capacity because of the heat that they generate. Plus there are other questions about whether the modules could be software limited in order to be in compliance with U.S. government policy” on the export of sensitive technology.

 

[GriffinsRule]

Now I can't remember if they were originally lighter or darker... Mandela effect... I could've sworn JF-17A had a darker radome.

Originally darker. I prefer the lighter color myself as well. Still not sure why they kept the lighting bolt on the sides though.

 

[The Eagle]

Aoa sir, I have failed to convey, sir if there are 50 JF 17 using air cooled AESA radar with package from east and 50 JF using liquid cooled AESA radar with package from west can be used as a pair and will able to deliver two kind of integrated weapons for just an example I.e SD 10 as well AMRAAM, then what is obstacle ? Two different Radar with two different package integrated???

My dear, there are no obstacles for the current fleet as we are using both the Eastern & Western tech i.e. F-16s, Mirages & JF-17 Thunders. However, Westerners have their own approach to sell something like an AESA Radar for PAF which is more of a concern in regard to have some political influence as compare to a simple weapon sale. This is the only obstacle as we fear that Western tech especially from US, will come with lot of strings attached especially the AESA. Hadn't been the issue of terms & conditions like that; we would have seen PAF placing an official order but unfortunately, there are lot of issues including CSF which was denied by US and Pakistan wants them to pay for us from the fund. Economical constrains plus those alleged strings. However, this time, the case may be different so let's see.

Radomes as you know are made from non metallic material and they cover the radar of an aircraft....lighter shade reportedly have less interruption in the radar signal.

We discussed back then when ceremony was held for handing over the overhauled birds. Radom colour was different after overhaul and as the chatter goes, even we could speculate some different internal setup for these birds being done during overhaul process but who knows.

 

[ziaulislam]

The Block 60s for UAE have liquid cooling:

FLIGHT TEST: Lockheed Martin F-16E/F Block 60 - Bridging the gap

www.flightglobal.com

I have found two different versions for APG-83. This source seems to imply purely air cooled solution:

https://www.matec-conferences.org/articles/matecconf/pdf/2019/53/matecconf_easn2019_04001.pdf

Whereas:

AESA Radar and Technology Developments | AIN

The technology features prominently in fighter competitions.

www.ainonline.com

Block 60 is 20 years old tech
New version of f16 AESA GaN are air cooled

 

[CriticalThought]

Block 60 is 20 years old tech
New version of f16 AESA GaN are air cooled

If you only cared to read the links I posted, you will realize that this 'new version' of F-16 is a rip off based on mid 2000s era technology. Go read those links.

 

[air marshal]

 

[Irfan Baloch]

After a better Engine gets loaded in Block III I would imagine the Jet would have ability to carry more Payload
in form of Multiple Missiles on Wings

Block III would give us option to Explore the ability to add missiles , or other weapons of choice

do you want this plane to resemble a typical overloaded Urban local transport?
do you want it to be able to take off at all or fall off the sky on a slight maneuvering?

 

[AZADPAKISTAN2009]

With Improved Jet Engine in Block III , the Engine will have no issue with Taking off with a larger load
BVR missiles would enable a good Long Range Engagement

For Dog Fight there won't be much lost in term of Agility and Flying capability

Twin Racks with BVR would be a Nice Addition post Block III

 

[MastanKhan]

the greatest mistake that the PAF has made is that they didn't take advice from you.

Hi,

They did not follow their own guidelines.

As much as Paf advertises of Pilots in total control of missions and flight parameters---it failed when the sh-it hit the fan.

 

[GumNaam]

Hi,

They did not follow their own guidelines.

As much as Paf advertises of Pilots in total control of missions and flight parameters---it failed when the sh-it hit the fan.

well enlighten me...what should have the PAF done in your expert opinion?

 

[MastanKhan]

It is not a dichotomy. There is no AESA radar out there that is cooled solely by air. Even the APG-83 has an inbuilt liquid heat exchanger for immediate removal of heat from the TRMs, and then this heat is further dissipated through air cooling. And all of the current technology has been created for GaAs based TRMs.

Based on the published research from Chinese scientists, I am making the assumption that the Block 3 radar is based on the newer GaN technology that uses SiC as the substrate layer. The SiC layer acts as the heat sink, thus removing the need for liquid cooling of the TRMs, and removing the need for bringing coolant into the radome. The bulk of the radar will be situated in the area under the cockpit and behind the nose cone. Luckily, there is already provisioning for cooling the cockpit!!! Now take a look at where the liquid cooling system of F-18 is situated:

LCDR Nate "Hyber" Marler Advanced Weapons Lab, VX-31 China Lake, Ca | PDF | Military Technology | Electronics

Includes cooling demand and probably cooling capacity for F/A-18E Radar.

www.scribd.com

And finally consider the fact that the base of Block-3 tail has an additional inlet for airflow. These are all the pieces of the puzzle that I currently have. People on this forum are not up to date with latest advancements in AESA technology and are getting confused based on what they know about existing GaAs based AESA radars.

Hi,

Let s for example look at engines---water cooled engines---they are also cooled by air---. There is a heat dissipation system---the radiator---that is in front of the incoming air.

The liquid cooled systems are basically less expensive

well enlighten me...what should have the PAF done in your expert opinion?

Hi,

What the israelis do all the time---.