Sukhoi PAK FA

[Armand2REP]

ORLY???
So why GaN TRMs have 65 to 85 percent of energy effectiveness while GaAs ones have 25% at maximum?
Energy effectiveness (and much less power consumption for a watt of transmitted energy) is the main GaN advantage.
The other advantages are much less requirements to cooling system (as a result of less power consumption and of course much higher temperature tolerance) and much better radiation resistance in high altitude and space.

Indeed, the difference is higher power density and wider bandgap. That doesn't mean it runs cooler. The more power you run through it the hotter it gets, far hotter than a GaAs would ever run. The requirements for the cooling system are far greater as the temperatures are far higher in accordance with the power curve.

 

[Steven Rogers]

Yes, but the main reason was engine and premature status.
Old GaAs based Zhuk-AE was rejected not for cooling reason but for its weight and power consumption.

And yes, Zhuk radars are not connected to T-50 tech level in any mean cause its's been developped by Phasotron company, that uses completely different technology chains and TRM vendors thsn NIIP that has designed Zaslon, Bars, Irbis and Belka radars.

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Indeed Su57 phase 2 is what India was promised and if it is what was promised then indeed it has the best AESA radar.

 

[Steven Rogers]

Indeed, the difference is higher power density and wider bandgap. That doesn't mean it runs cooler. The more power you run through it the hotter it gets, far hotter than a GaAs would ever run. The requirements for the cooling system are far greater as the temperatures are far higher in accordance with the power curve.

Does any one knows what thermal conductivity is....... Post a message not less than 30 words.

 

[Armand2REP]

Does any one knows what thermal conductivity is....... Post a message not less than 30 words.

You are talking about the substrate which is what the GaN is cast on, not the GaN itself.

 

[Steven Rogers]

You are talking about the substrate which is what the GaN is cast on, not the GaN itself.

I talking about GaN itself, not the with the substrate

 

[gadeshi]

Indeed, the difference is higher power density and wider bandgap. That doesn't mean it runs cooler. The more power you run through it the hotter it gets, far hotter than a GaAs would ever run. The requirements for the cooling system are far greater as the temperatures are far higher in accordance with the power curve.

Wrong.
1 - GaN cirquits have less parasite impedance than GaAs and this defines less power consumption and higher efficiency as well as much less TDP.
2 - As a consequence of 1, power efficiency works in both directions: you can get more power transfer in the current cooling system capacity, dramatically encrease power transfer at the price of cooling system capacity growth or get cool-less TRMs like flat LTCC ones in Zhuk-AM radar or L-402 Gimalayi ESM/ECM suite "smart skin" embedded modules or R-77M (Item 180) active/passive seeker.

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[Armand2REP]

I talking about GaN itself, not the with the substrate

It is the substrates that transfer the heat. Without that the heat will just stay on the module making the thermal conductivity of the GaN irrelevant. What is special about GaN is that it can withstand higher heat but you still have to cool it more than a GaAs when you will be pumping several times more power through it.

 

[Steven Rogers]

It is the substrates that transfer the heat. Without that the heat will just stay on the module making the thermal conductivity of the GaN irrelevant. What is special about GaN is that it can withstand higher heat but you still have to cool it more than a GaAs when you will be pumping several times more power through it.

Simply asking the definition of thermal conductivity...

 

[Steven Rogers]

GaN has 3ce the thermal conductivity than the GaA, at same poweroutput GaN is thrice less heat radiator than the GaA, even if it matches the heat of GaA it jumps thrice the performance than that of GaA.... That means it is thrice more efficient than the GaA with available cooling meant of GaA max performance . Now comes next gen radars, they are made with GaN, that means cooling system derived for GaN to extract more performance from it....... Even at present cooling systems GaN is performing 3rce more performance pack than the GaA.

 

[Steven Rogers]

It is the substrates that transfer the heat. Without that the heat will just stay on the module making the thermal conductivity of the GaN irrelevant. What is special about GaN is that it can withstand higher heat but you still have to cool it more than a GaAs when you will be pumping several times more power through it.

Every GaN module anywhere in the world has a substrate Al in that for heat exchange, and prevent Ga from melting. You have to cool it, but compared to GaA cooling will be equivalent with thrice the performance, in the case of radars as a 20kW airborne radar with GaN will require many times less cooling than a 20kW airborne radar with GaA. Also the GaN will be performing at high challenging atmosphere such as deserts with higher poweroutput when GaA generally melts even with the cooling at such place. Ex-Many cases with Su30mki radars... ...

 

[Armand2REP]

Every GaN module anywhere in the world has a substrate Al in that for heat exchange, and prevent Ga from melting. You have to cool it, but compared to GaA cooling will be equivalent with thrice the performance, in the case of radars as a 20kW airborne radar with GaN will require many times less cooling than a 20kW airborne radar with GaA. Also the GaN will be performing at high challenging atmosphere such as deserts with higher poweroutput when GaA generally melts even with the cooling at such place. Ex-Many cases with Su30mki radars... ...

What are you talking about? Most GaN substrate is on SiC. The problem is the expense is anywhere from €2000-5000 per wafer due to the high price of GaN epitaxy. AlGaN is just the top layer used as a buffer, it is not a substrate. This is what the three major types of GaN wafer stacks look like...

 

[Steven Rogers]

What are you talking about? Most GaN substrate is on SiC. The problem is the expense is anywhere from €2000-5000 per wafer due to the high price of GaN epitaxy. AlGaN is just the top layer used as a buffer, it is not a substrate. This is what the three major types of GaN wafer stacks look like...

Yeah you are right, a sapphire substrate is used while AlGaN is used as a barrier and GaN is used as a buffer

 

[gadeshi]

A KS-111 digital network communication system little info from expo:

 

[gadeshi]

More T-50-11 (1-11) for your pleasure:

 

[gadeshi]

Possible Su-57K (Su-53) front/rear view retracted sizes:

 

[pankaj nema]

EXCLUSIVE: IAF flags concerns about Fifth Generation Fighter deal. Can India cancel it?

http://www.timesnownews.com/india/a...mme-fgfa-india-russia-indian-air-force/108413

 

[shuvo@y2k10]

Better to go alone in FGFA since HAL has a airframe designed keeping IAF ASQR in mind based on PAK-FA. Invest more in AMCA project. No point in investing 7 billion dollars on PAK-FA when 2-3 indegeneous fifth gen fighter projects can be financed with it in light (Tejas Mk3 ALCA), medium (AMCA) and heavy (AHCA) as well as Ghatak UCAV.

 

[gadeshi]

=========================================

 

[WolfPack86]

EXCLUSIVE: IAF FLAGS CONCERNS ABOUT FIFTH GENERATION FIGHTER DEAL. CAN INDIA CANCEL IT?
New Delhi: The Narendra Modi government now has a problem on its hands. The Indo-Russian Fifth Generation Fighter Programme (FGFA) was planned about a decade ago and several billion dollars have been spent by both the countries for its design and development.

As far as the Indian Air Force is concerned, the FGFA was part of its future. But with the IAF giving the government its doubts about the project in writing, the Modi government will have problems on its hands. Will it accept the IAF's point and close the programme it has heavily invested in for years? This becomes tricky as the Russians are still India's closest military ally and a decision to not go ahead with it could strain ties. There will also, most certainly, be pressure from the Russians. Going ahead with it would also make the Air Force unhappy.

Along with a report by Air Marshal S Varthaman (retired), the Air Force has sent a note to the Defence Ministry. The note is written by Assistant Chief of Air Staff (Plans) Air Vice Marshal BV Krishna. But while the Varthaman report appears to support the project, the Krishna papers raise doubts. Naturally, the government will have to go by what the Air Force wants and at this point, the IAF does not seem very keen.

Arun Jaitley, the then defence minister, has already sat through a presentation on the subject. At a recent press conference, IAF chief Air Chief Marshal BS Dhanoa refused to speak about the subject, saying it was classified. But several points about the Air Force's dissatisfaction with the plane have emerged.

1. The radar cross-section surface area, according to the Russians, will be less than 0.5-metre square. The IAF isn't quite sure that will be the case. In any case, there is a belief it should be 0.2-metre square, comparable with the F-35, the American fighter plane. The higher the cross-section, the more visible the plane to radars, making it easier to track it down and fire missiles at it. A higher cross section makes it more vulnerable.

2. The IAF seems to have doubts about the performance of the engine. An engine is easier to maintain if it follows the "modular concept". There appears to be no certainty if that will be so.

3. There is also the issue of maintenance. The Russian aircraft are usually cheaper but they cost more when it comes to maintenance. The FGFA, however, has been an expensive plane to develop and it is still far from ready. Initially, it was felt the plane would be ready by 2017 and then, 2019. That seems unlikely now.

The note has come in the wake of the Varthaman report which has given the fifth generation fighter the go-ahead. The Air Force apart, the DRDO, the ADA and the HAL were part of the study.
Now, high-level sources said a political decision has to be taken.
India and Russia were close military-strategic allies and this programme was part of the future as far as the two countries were concerned. Russia has supplied India with a nuclear-powered submarine, a point its officials often make. But with the Air Force not very happy with the FGFA, it will be up to the government to do decide whether the deal goes through or not. The decision will also have to be taken at the highest level. There are some concerns about what happens if the deal falls through. Would the Russians play hardball on the S-400 air defence system deal? That is something India wants.
http://www.indiandefensenews.in/2017/10/exclusive-iaf-flags-concerns-about.html

 

[WolfPack86]

This is a crap article already ministry panel had given a go ahead for the deal. FGFA deal will be signed very soon.
http://www.hindustantimes.com/india...s-top-panel/story-mPrhroM6ftEOSFldOtunnJ.html