PAK-FA and FGFA: News & Discussion - June 2014

[deejay]

^^^"EFT's is not be stealthy but to extend the range either for ferry or for tactical advantage"
Of course, but when one is touting, the PAK/FA as a 'stealthy a/c' with an effective/superior combat range, it hardly helps that you've got these beacons pinpointing you because they are extending your range.

If you want the tactical advantage of more fuel, you can get the 4G a/c like the F-16s/Rafales with a panoply of non conformal EFTs at a much lower price.

What is the point of showing a purportedly 5G a/c with EFTs? Ability to leave Florida in a hurry?

Sir, are you opposing because you must?

[JayS]

^^^"EFT's is not be stealthy but to extend the range either for ferry or for tactical advantage"
Of course, but when one is touting, the PAK/FA as a 'stealthy a/c' with an effective/superior combat range, it hardly helps that you've got these beacons pinpointing you because they are extending your range.

If you want the tactical advantage of more fuel, you can get the 4G a/c like the F-16s/Rafales with a panoply of non conformal EFTs at a much lower price.

What is the point of showing a purportedly 5G a/c with EFTs? Ability to leave Florida in a hurry?

It should be obvious enough that any 5G fighter won't be going around with ETF or any kind of external load when it wants to hide, e.g. on SEAD/DEAD mission on Day 1 of war in a heavily defended enemy airspace.

Apart from very obvious use in Wars, ETFs can be useful in peacetime too. They increase range and time of each flight without costly IFR when its not absolutely necessary to have one. Aircrafts fly much more in peacetime than in wars. ETFs can be an easy and cheap option to save some of the precious airframe time and reduce unnecessary IFR.

[Gaur]

^^
True. Russia is a big country. For instance, distance from Komsomolsk (where Su-57 is manufactured) is manufactured to Akhtubinsk (where it is tested) is roughly 8,500 Kms. I am sure the drop tanks would be a boon here.

[sarang]

so, they ARE supersonic and they also have huge capacity,

Their signature must also be huge,

What I find odd is; they are on a stealthy aircraft...

OR

may be they are for test aircraft only and not for actual military use....

[Indranil]

Sirjee,

This much should be obvious: Low signature is not the requirement of every mission.

[Karan M]

^^^"EFT's is not be stealthy but to extend the range either for ferry or for tactical advantage"
Of course, but when one is touting, the PAK/FA as a 'stealthy a/c' with an effective/superior combat range, it hardly helps that you've got these beacons pinpointing you because they are extending your range.

If you want the tactical advantage of more fuel, you can get the 4G a/c like the F-16s/Rafales with a panoply of non conformal EFTs at a much lower price.

What is the point of showing a purportedly 5G a/c with EFTs? Ability to leave Florida in a hurry?

Sir, are you opposing because you must?

Exactly..
https://upload.wikimedia.org/wikipedia/ ... _tanks.jpg
F-35 linky

[SaiK]

[brar_w]

^^^"EFT's is not be stealthy but to extend the range either for ferry or for tactical advantage"
Of course, but when one is touting, the PAK/FA as a 'stealthy a/c' with an effective/superior combat range, it hardly helps that you've got these beacons pinpointing you because they are extending your range.

If you want the tactical advantage of more fuel, you can get the 4G a/c like the F-16s/Rafales with a panoply of non conformal EFTs at a much lower price.

What is the point of showing a purportedly 5G a/c with EFTs? Ability to leave Florida in a hurry?

It should be obvious enough that any 5G fighter won't be going around with ETF or any kind of external load when it wants to hide, e.g. on SEAD/DEAD mission on Day 1 of war in a heavily defended enemy airspace.

Apart from very obvious use in Wars, ETFs can be useful in peacetime too. They increase range and time of each flight without costly IFR when its not absolutely necessary to have one. Aircrafts fly much more in peacetime than in wars. ETFs can be an easy and cheap option to save some of the precious airframe time and reduce unnecessary IFR.

Yup. No one wants an F117 anymore. All demand the maximum flexibility for their buck which means multiple possible configurations ranging from all internal fuel and weapons for strike against highly defended targets, or for offensive counter air, to the ability to morph into something more effective when the enhanced survivability is not required. On the F-22 they even went as far as demanding jettison-able pylons. Modern 4+ generation aircraft currently such as the Rafale, and Typhoon (and likely the Block 3 Super Hornet) nearly cost as much as 5th generation aircraft, and the cost curves are likely headed in the opposite direction for each.

No operator looking into the future would want to buy one 5th generation aircraft for the ability to function in environments where enhanced survivability is required and another advanced 4 gen aircraft when the environment is less threatening. At some point, most advanced 4th generation production will shut down and transition to 5th generation and drones. This will likely happen in the west around the middle of next decade (barring one or two programs perhaps) and will likely happen in Russia in the late 2020s or early 2030s with the production of the PAKFA eventually replacing the Flanker family out into the future, and a new "Space Age Fighter" coming online, along with one more 5th generation aircraft for the ME market.

[sarang]

Sirjee,

This much should be obvious: Low signature is not the requirement of every mission.

Agreed.

[Cosmo_R]

Sir, are you opposing because you must?

Exactly..
https://upload.wikimedia.org/wikipedia/ ... _tanks.jpg
F-35 linky

Gentlemen, you miss the point. When the JSF was discussed in its own thread, many on BRF scoffed at the bomb load in stealth configuration. Short legs, small payload. When it was pointed out that you could hang a lot of stuff from the wings including EFTs, it was derided as negating the basis of a stealth platform.

When I now see the PAK/FA claiming EFTs as a virtue, I find it inconsistent.

So, no I don't suffer from oppositional defiance disorder. I do however suffer from the need to be consistent. It helps keep the discussions on an even keel.

[JayS]

Exactly..
https://upload.wikimedia.org/wikipedia/ ... _tanks.jpg
F-35 linky

Gentlemen, you miss the point. When the JSF was discussed in its own thread, many on BRF scoffed at the bomb load in stealth configuration. Short legs, small payload. When it was pointed out that you could hang a lot of stuff from the wings including EFTs, it was derided as negating the basis of a stealth platform.

When I now see the PAK/FA claiming EFTs as a virtue, I find it inconsistent.

So, no I don't suffer from oppositional defiance disorder. I do however suffer from the need to be consistent. It helps keep the discussions on an even keel.

But no one making ETF as any kind of virtue for PAKFA here. Someone just posted pics, thats it. You are trying to make it as some kind of negative point. I dont know who said what about which fighter and when, but its hilarious to use that to say what you say about PAKFA. If you think that was stupid to say about JSF, what you are doing is no smarter. Do you see the irony...?

[Cosmo_R]

^^^Don't see any irony. Look up the JSF Turkey or Talisman thread and you will get a handle on the past discussions. I reserve the right to make a comment on a picture when it portrays carrying EFTs as some sort of great milestone. I'm not sure why you take it so personally and infuse it with a schoolmasterish disapproval. There's always the 'ignore button'

Let's get on with maintaining a balanced discussion.

[Austin]

Interview with United Engine Corporation Chief on New features of 117 Engine currently on PAK-FA compared to 117S Engine on Su-35 and AL-31F on Su-30

http://vpk-news.ru/articles/8228

1 ) there will be new ceramic materials can withstand very high temperatures.
2 ) High-pressure turbine can operate without cooling blades, bearings - no lubrication.
3 ) Inlet temperature exceeds the temperature of the combustion theater kerosene at 2300 degrees.
4 ) The engine is a new low-pressure compressor.
5 ) Substantially upgraded high-pressure compressor.
6 ) The new combustion chamber.
7 ) The new turbine.
8 ) Almost all new units 80 % new parts compared to 117S
9 ) Weight Reduction of 150 kg link
10 ) Fundamentally new system of automatic control system (ACS) - fully digital, with full responsibility. For the first time it will be built at the Russian element basis. Architecture of the system, the control algorithm and its Russian counterparts

[Austin]

[JayS]

Interview with United Engine Corporation Chief on New features of 117 Engine currently on PAK-FA compared to 117S Engine on Su-35 and AL-31F on Su-30

http://vpk-news.ru/articles/8228

1 ) there will be new ceramic materials can withstand very high temperatures.
2 ) High-pressure turbine can operate without cooling blades, bearings - no lubrication.
3 ) Inlet temperature exceeds the temperature of the combustion theater kerosene at 2300 degrees.
4 ) The engine is a new low-pressure compressor.
5 ) Substantially upgraded high-pressure compressor.
6 ) The new combustion chamber.
7 ) The new turbine.
8 ) Almost all new units 80 % new parts compared to 117S
9 ) Weight Reduction of 150 kg link
10 ) Fundamentally new system of automatic control system (ACS) - fully digital, with full responsibility. For the first time it will be built at the Russian element basis. Architecture of the system, the control algorithm and its Russian counterparts

Interesting. Google Translation output is not very good. But the bolded part is very interesting. I totally don't understand what he really wats to say in point 3. Google translates it as:

The temperature at the TVD inlet will exceed the combustion temperature of kerosene by 2300 degrees

If it is Turbine inlet temperature in degree centigrade, which is what it looks like in all probability, and coupled with un-cooled HPT blades, this can mean only one thing - CMC blades in HPT. That would be a huge breakthrough. Significantly better than the state-of-the-art anywhere in the world.

But I am confused. Isn't these new features for Izdeliye-30 vis-à-vis 117s (=AL41)...? Which is yet to be test flown..?

[Austin]

But I am confused. Isn't these new features for Izdeliye-30 vis-à-vis 117s (=AL41)...? Which is yet to be test flown..?

That interview I posted was of 2011 when 117 Engine of PAK-FA was going through state test and he is comparing it with 117S of Su-35.

Id 30 engine is classified program till date and no information is known other then the number of stages and rough figures thrust I posted Piotr Article on that previous page.

Here is Yandex Translation of interview https://translate.yandex.com/translate

Q – How to cut?

– The use of new materials, achieved developments in the other sectors, technical knowledge. There is good reason to what we can do not only competitive aircraft engine for the PAK FA, but also aircraft engines next generation.

Now all gas turbine engines is implemented so-called Brayton cycle: supply of heat at constant pressure. Of the possibility of such engine is approaching its limit, he is actually exhausted, as exhausted at the time a piston engine. Of course, you can increase the efficiency by two to three percent, but in General it does not solve the problem. The problem is that the specific thrust increased by 50-60 percent.

In pure science discoveries are made, which are able to drastically affect the development of technology. But the development of technical systems goes in steps, incrementally. Here is the engine for the PAK FA though will surpass all the parameters of the already established engines, however, will be made using existing scientific and technical base.

Of course, there will be new ceramic materials that can withstand very high temperatures. High pressure turbine can operate without cooling blades, bearings – no grease.The temperature at the inlet of the HPT will exceed the combustion temperature of kerosene at 2300 degrees. This will limit opportunities for improving the parameters of modern aircraft engine. The present appearance of the engine will remain fifteen to twenty years. A lot depends on how quickly you begin to improve material properties.

Q Is a more distant prospect. Let's still talk about our time. What is the current engine for the PAK FA?

Now for the PAK FA made the engine, with the symbol of the "product 117". He is at the stage of the preliminary test – bench and flight that are successful. Some elements borrowed from the practices to build the engine "117S" for the su-35, in particular design methods and calculations, processing technology of complex structural elements.

Engine "117C" – is not an easy modernization of AL-31F, as sometimes you can read in the press. Pull on his two tons higher than AL-31F. Get these two tons in the same dimensions is not easy. The engine is a new low-pressure compressor. Substantially upgraded high-pressure compressor. The new combustion chamber. New turbine. Almost all components are new. The engine is 80 percent new parts.

And the "product 117" for the PAK FA first phase (T-50) pull more than the "117S" (Su-35 ).

Moreover, it is essentially a new automatic control system (ACS) is a fully digital, with full responsibility. For the first time, it will be built on the Russian element base. The architecture of the system, the control algorithm it is also Russian. We want element base was Russian, although we have a list of permissions to use foreign bases. Such in the domestic engine was not. To address this problem, the Ministry of industry and trade of the Russian Federation allocates funds.Conducted research work titled "ACS promising products." Got a good team of designers ACS, there is a Foundation and we do not doubt the success.

[JayS]

But I am confused. Isn't these new features for Izdeliye-30 vis-à-vis 117s (=AL41)...? Which is yet to be test flown..?

That interview I posted was of 2011 when 117 Engine of PAK-FA was going through state test and he is comparing it with 117S of Su-35.

Id 30 engine is classified program till date and no information is known other then the number of stages and rough figures thrust I posted Piotr Article on that previous page.

Here is Yandex Translation of interview https://translate.yandex.com/translate

Alright. I didn't notice date. I have doubt on the claim "HPT without cooled blades and 2300deg TIT". Because their dry to wet thrust ratio and wet T:W does not match expectations if we assume this claim is true. For comparison F135 hits TIT of 2000deg C, highest number I have seen ever, and I can easily trust this number to be true.

[Austin]

The T:W Ratio of 117 is known and its 15T , No reason do doubt those figures as its from hourse mouth and F135 engine is not a bench mark for them to follow as PAK-FA and F-35 dont have the same ASR from their respective airforces. simple eg would be PAK-FA is designed to supercruise while F-35 is not by design

Not to mentioned Id 30 would have much less number of stages and higher thrust than 117 ......Metallurgy is key Russian Strength

[JayS]

The T:W Ratio of 117 is known and its 15T , No reason do doubt those figures as its from hourse mouth and F135 engine is not a bench mark for them to follow as PAK-FA and F-35 dont have the same ASR from their respective airforces.

Not to mentioned Id 30 would have much less number of stages and higher thrust than 117 ......Metallurgy is key Russian Strength

You mean Trust is 15T, not T:W. Wiki says T:W of 10.5 for 117. For I-30 I have seen claim of 11.5.

Well, F135 is not a benchmark but Physics doesn't change for Russians. The only remotely possible way of having uncooled blades in HPT is to have CMC blades. Even then I have so far, in my limited knowledge, not seen anyone claiming uncooled blades for HPT. For LPT, yes possible. The interview was from 2011 and its 2017 now. The research in CMC is still primitive and to my knowledge no one has put them in HPT. I recently saw a papar from a Japanese group in latest ASME Turbo Conference a couple of months ago, where they did some lab testing on CMC HPT "nozzle" vanes. They did test CMC without TBC and cooling holes (due to lack of coupon tests data with TBC) but then the temperature was limited to merely 1200deg C and runs of few minutes at a time. When you want to make rotor blades structural strength comes into picture as well in addition to only thermal resistance demonstrated here.

If someone told me I-30 will uncooled blades in HPT, I would still see it with doubt let alone 117 having it. If Russians have found out some exotic material to withstand 2300deg C, then I don't know. But I need to see a stronger evidence to take it as truth. To achieve the figures that Russians claim for 117 or for I-30, one does not need uncooled blades in HPT or 2300C TIT.

[Austin]

If someone told me I-30 will uncooled blades in HPT, I would still see it with doubt let alone 117 having it. If Russians have found out some exotic material to withstand 2300deg C, then I don't know. But I need to see a stronger evidence to take it as truth. To achieve the figures that Russians claim for 117 or for I-30, one does not need uncooled blades in HPT or 2300C TIT.

What strong evidence does one need , The 117 engine outclass the F-22 engine in T:W ratio and every other western engine lets say barring the F-135 but the F-135 is not designed to supercruise while the 117 has it , The only western engine I know of T:W ratio of 10:1 is the EJ200 . The only evidence one would get is from such interviews ...... the other is to search for Patents but if we dont understand crylic then search them is like needle in hay stack.

If you read the full interview he even mentioned that 117S engine of Su-35 was not an easy task to achieve 2 T more thrust keeping the weight and dimension same , the AL-31 F is what our MKI uses

[brar_w]

There is no definitive information on the actual amount of thrust, or the weight of the F119 so a direct comparison is moot. Information released points to a general description as "35,000 lb thrust class" and on occasions, >35,000 lb. thrust etc. Same with configurations. There are/were variants of the F119 that have demonstrated >38,000 lb of thrust so I think until there are confirmed data for both thrust and weight it is not possible to compare.

[Austin]

UASF and P&W puts the thrust at 35,000 lb and Rand has put its weigh at 3,900 lb

http://www.af.mil/About-Us/Fact-Sheets/ ... -22-raptor
http://www.pw.utc.com/F119_Engine
http://www.rand.org/pubs/monograph_repo ... MR1596.pdf

[brar_w]

The link you have provided clearly states exactly what I have said in my previous post i.e. " 35,000 lb Class". On the weight issue, they do not elaborate what this includes in terms of the LO requirements, variables that may not be present in other systems rendering direct comparisons difficult. Notice that there are hardware features on the F119 that help it meet this requirement, and then you have differently shaped TV nozzles which have an integration cost as well.

As I mentioned, definitive information on max. thrust is not available on the 119. In the past the USAF and P&W have used terms like 35,000 thrust class, >35,000 lb of thrust, and on occasions even 35,000 - 40,000 lb thrust class to describe this engine. Folks have reported each of these including Guy Norris who has done a great job on capturing engine development over the years for various publications he has worked for.

[Austin]

Well yes there are ceremic tiles even on the inside of nozzle of 117 Engine to reduce its temp/IR signature

[brar_w]

Well yes there are ceremic tiles even on the inside of nozzle of 117 Engine to reduce its temp/IR signature

I'm not referring to just the use of ceramics.

Specifically, to the F119, here are excerpts from what Bill Sweetman reported on the F119 back when he was with IDR -

Although the thrust of the F119 is officially quoted as `in the 155kN class', information obtained by IDR suggests that the actual thrust may be more than 170kN with full augmentor, implying an intermediate (non‐ augmented) rating of 113kN. This is compatible with statements that at supersonic speed, on dry thrust, the F119 generates twice as much power as the F100‐PW‐200. The F119 has not been shown in public, but General Electric has exhibited the rival F120 in partly disassembled form, mounted alongside an F110 ‐ the difference in the size of the core blading was considerable. These are huge engines, capable of delivering 180kN without afterburning when fitted with a larger fan for the Boeing JSF design.

[Austin]

Quite possible , Even the 117 engine of PAK-FA has not been shown in public , no one will show all their cards if the engines are exotic.

[brar_w]

We had earlier (on another thread iirc) discussed some of the other (besides the use of ceramics on the unique nozzles on the F22) features the F-119 and -135 use to aid in LO, clearly a requirement on these propulsion systems that was stringent enough to demand hardware additions which naturally come with a performance penalty just like those nozzles.

[JayS]

If someone told me I-30 will uncooled blades in HPT, I would still see it with doubt let alone 117 having it. If Russians have found out some exotic material to withstand 2300deg C, then I don't know. But I need to see a stronger evidence to take it as truth. To achieve the figures that Russians claim for 117 or for I-30, one does not need uncooled blades in HPT or 2300C TIT.

What strong evidence does one need , The 117 engine outclass the F-22 engine in T:W ratio and every other western engine lets say barring the F-135 but the F-135 is not designed to supercruise while the 117 has it , The only western engine I know of T:W ratio of 10:1 is the EJ200 . The only evidence one would get is from such interviews ...... the other is to search for Patents but if we dont understand crylic then search them is like needle in hay stack.

If you read the full interview he even mentioned that 117S engine of Su-35 was not an easy task to achieve 2 T more thrust keeping the weight and dimension same , the AL-31 F is what our MKI uses

Austin, increase of 2.5T thrust in AL31FP is not a big deal, per se. Lets not see it in isolation. Al31 is yesteryear's engine by any standard - full 3 generations behind engines like EJ200, F414-EE or F119 (2 for technology in terms of T:W and 1 for terrible life). Russians found it hard means nothing in terms of Physics of the problem. Others have solved it already. By that standard Kaveri must be the best engine in the world, because we Indians cannot make it however hard we try to make it, no..??

BTW F414-EE is also T:W 10 class.

See, 300 deg jump over F135 is no small thing. With that and uncooled blades (significant reduction in chargeable air), if they are still at T:W = 10.5 then they must have fckued up real bad on other components. Logically speaking its far more probable that Russians achieved the increased T:W over Al31 from application of advanced 3D Aerodynamics and better manufacturing processes like blisks and AM which are low hanging fruits, than CMC. It could be possible they made some magic TBC to eliminate cooling for conventional SCBs, but TBC has significant negative effect on structural life. Here they claim double life for this engine over that of AL31. I don't care how good or bad Russians are in metallurgy, arguments for this particular issue should stand on their own merits.

I don't say it impossible, I can think of two ways to get there - CMC or some magic TBC. I would be thrilled if the Russians actually have the breakthrough of uncooled HPT blades and 2300C TIT. Because it a big achievement technologically speaking. And IAF will probably get those engines for Su-30 upgrade and Initial batch of PAKFA (or a even better I-30), if we ever decide to buy it. But I need to see it to believe it, through some research paper or technical article giving little more specific details of what they are doing, or at least corroboration from multiple sources. I know it may not be possible to find verification easily, but I will remain sceptical until I see something.

Austin, you mentioned significant reduction in stages. Al31F or 117s have too many stages. So reduction is not surprizing. 3 LPC, 5-6 HPC, 1 HPT and 1LPT is what one should expect reasonably for any 5th gen engine (not fighter generation but engine's genration).

A question to brar_w. OT here, may can be taken to Engine thread. Whats the weight of F119..? The weight quoted on wiki ~1800kg, is that including the TVC in it..?? Looks higher to me than expected. PS: I saw you already talked about this one in one of the posts above.

[Austin]

AL-31FP would be like 1 gen behind EJ in terms of TW ~ 8:1 but EJ still doesn't have a 2.5 TVC that is on any production ready aircraft flying for decades

If you are looking at pure T:W then even the snecma m88-2 lags behind EJ

[brar_w]

Thrust vectoring does not have anything to do with the engine performance but more to do with requirements that drive the airframe prime to seek for that solution. Notice that having access to one of the first 3D TV systems in the world, Lockheed sought a 2D system from P&W and GE even though the ATF did not specify TVC as a requirement (and actually force Lockheed to make the control services larger in case TV was eliminated on insistence from the customer). Northrop sought neither even though they had access to the same systems Lockheed had.

[Austin]

Doesn't matter if experiments go by then there are many things out there production ready flying for decades in operational airforce integrated with FBW is something else

[brar_w]

So how does that affect the quality of their engine? TV is an independent variable that aircraft designers can choose to incorporate or not and seek solutions from propulsion suppliers to that end. It does not make one engine superior or technologically more advanced than the other.

[Austin]

It does if the other does not have it , remember mki spanked the eurofighter in India dhanush and low speed handling capability is as much of engine as its TVC

[brar_w]

No it does not. Notice what jay was referring to - the EJ-200, F414 etc etc etc. He was not talking about the Typhoon, Super Hornet, Gripen, LCA etc. The engines did not dogfight each other, the aircraft did. He was specifically referring to the engine technology.

[NRao]

I think the Russians claim Izdeliye-30 to be a clean-sheet effort. If true, we should expect a few new tech breakthroughs. And, the Russians are more than capable in this area. Time is all they need.

[Austin]

No it does not. Notice what jay was referring to - the EJ-200, F414 etc etc etc. He was not talking about the Typhoon, Super Hornet, Gripen, LCA etc. The engines did not dogfight each other, the aircraft did. He was specifically referring to the engine technology.

You cant seperate Engine Technology needed for TVC because a lot of low speed flights and high angle of attack afforded by TVC where your air intake is sucked of air/oxygen but engine still has to to be robust enough to keep working without flaming out , If they try to do MKI like low speed charactesistics and extereme manouverability with TVC chances are the engine will just flame out.

TVC is not something you can randomly fit into any engine without understanding how engine will work in all the regiems of flight and high AOA or NO AOA , this is something an aircraft engine does it but TVC just extends the benchmark to another level

[brar_w]

deleted

[Austin]

T-50-11 Gray Ghost Cammo

[Sumeet]

Its beautiful

[Gaur]

Cross Post from Single Engine Thread

http://economictimes.indiatimes.com/news/defence/iaf-to-start-process-to-acquire-single-engine-jets-this-month/articleshow/60958830.cms

Asked about the fifth-generation fighter aircraft project (FGFA) with Russia, Dhanoa said a high-level committee has submitted its report to defence ministry which will take a call on it.

"The case is with the ministry of defence. The preliminary design phase has been completed. The Varthaman committee has submitted its report which is classified and we have also given our response," Dhanoa said.